Sample records for short revisit time

  1. The Late-time Afterglow of the Extremely Energetic Short Burst GRB 090510 Revisited

    NASA Technical Reports Server (NTRS)

    Guelbenzu, A. Nicuesa; Klose, S.; Kruehler, T.; Greiner, J.; Rossi, A.; Kann, D. A.; Olivares, F.; Rau, A.; Afonso, P. M. J.; Elliott, J.; Filgas, R.; Yoldas, A. Kuepcue; McBreen, S.; Nardini, M.; Schady, P.; Schmidl, S.; Sudilovsky, V.; Updike, A. C.; Yoldas, A.

    2012-01-01

    Context. The Swift discovery of the short burst GRB 090510 has raised considerable attention mainly because of two reasons: first, it had a bright optical afterglow, and second it is among the most energetic events detected so far within the entire GRB population (long plus short). The afterglow of GRB 090510 was observed with Swift/UVOT and Swift/XRT and evidence of a jet break around 1.5 ks after the burst has been reported in the literature, implying that after this break the optical and X-ray light curve should fade with the same decay slope. Aims. As noted by several authors, the post-break decay slope seen in the UVOT data is much shallower than the steep decay in the X-ray band, pointing to a (theoretically hard to understand) excess of optical flux at late times. We assess here the validity of this peculiar behavior. Methods. We reduced and analyzed new afterglow light-curve data obtained with the multichannel imager GROND. These additional g'r'i'z' data were then combined with the UVOT and XRT data to study the behavior of the afterglow at late times more stringently. Results. Based on the densely sampled data set obtained with GROND, we find that the optical afterglow of GRB 090510 did indeed enter a steep decay phase starting around 22 ks after the burst. During this time the GROND optical light curve is achromatic, and its slope is identical to the slope of the X-ray data. In combination with the UVOT data this implies that a second break must have occurred in the optical light curve around 22 ks post burst, which, however, has no obvious counterpart in the X-ray band, contradicting the interpretation that this could be another jet break. Conclusions. The GROND data provide the missing piece of evidence that the optical afterglow of GRB 090510 did follow a post-jet break evolution at late times. The break seen in the optical light curve around 22 ks in combination with its missing counterpart in the X-ray band could be due to the passage of the injection frequency across the optical bands, as already theoretically proposed in the literature. This is possibly the first time that this passage has been clearly seen in an optical afterglow. In addition, our results imply that there is no more evidence for an excess of flux in the optical bands at late times.

  2. Revisiting timing in process algebra

    Microsoft Academic Search

    C. A. Middelburg

    2002-01-01

    We shortly review the framework of process algebras with timing presented by Baeten and Middelburg [Handbook of Process Algebra, Elsevier, 2001, Chapter 10]. In order to cover processes that are capable of performing certain actions at all points in some time interval, we add integration to the process algebra with continuous relative timing from this framework. This extension happens to

  3. Revisiting timing in process algebra

    Microsoft Academic Search

    C. A. Middelburg

    2003-01-01

    We shortly review the framework of process algebras with timing presented by Baeten and Middelburg [Handbook of Process Algebra, Elsevier, 2001, Chapter 10]. In order to cover processes that are capable of performing certain actions at all points in some time interval, we add integration to the process algebra with continuous relative timing from this framework. This extension happens to

  4. Short Communication: Earth is (mostly) flat, but mountains dominate global denudation: apportionment of the continental mass flux over millennial time scales, revisited

    NASA Astrophysics Data System (ADS)

    Willenbring, J. K.; Codilean, A. T.; Ferrier, K. L.; McElroy, B.; Kirchner, J. W.

    2014-01-01

    Carbon dioxide consumption by silicate mineral weathering and the subsequent precipitation of carbonate sediments sequesters CO2 over geologic timescales. The rate of this carbon sequestration is coupled to rates of continental erosion, which exposes fresh minerals to weathering. Steep mountain landscapes represent a small fraction of continental surfaces but contribute disproportionately to global erosion rates. However, the relative contributions of Earth's much vaster, but more slowly eroding, plains and hills remain the subject of debate. Recently, Willenbring et al. (2013) analyzed a compilation of denudation rates and topographic gradients and concluded that low-gradient regions dominate global denudation fluxes and silicate weathering rates. Here, we show that Willenbring et al. (2003) topographic and statistical analyses were subject to methodological errors that affected their conclusions. We correct these errors, and reanalyze their denudation rate and topographic data. In contrast to the results of Willenbring et al. (2013), we find that the denudation flux from the steepest 10% of continental topography nearly equals the flux from the other 90% of the continental surface combined. This new analysis implies global denudation fluxes of ∼23 Gt yr-1, roughly five times the value reported in Willenbring et al. (2013) and closer to previous estimates found elsewhere in the literature. Although low-gradient landscapes make up a small proportion of the global fluxes, they remain important because of the human reliance, and impact, on these vast areas.

  5. Short Signatures from Diffie-Hellman, Revisited: Sublinear Public Key, CMA Security, and Tighter Reduction

    E-print Network

    Short Signatures from Diffie-Hellman, Revisited: Sublinear Public Key, CMA Security, and Tighter UnForgeability against Chosen Message Attack (EUF-CMA) with nearly optimal reduction. However's approach could prove only a rather weak security, called the bounded CMA security, and B¨ohl et al

  6. Concurrent Zero-Knowledge With Timing, Revisited Oded Goldreich

    E-print Network

    Goldreich, Oded

    Concurrent Zero-Knowledge With Timing, Revisited Oded Goldreich Department of Computer Science-going messages). We show that the constant-round zero-knowledge proof for NP of Goldreich and Kahan (Jour under the above timing model. We stress that our main result refers to zero-knowledge of interactive

  7. Concurrent Zero-Knowledge With Timing, Revisited Oded Goldreich

    E-print Network

    Goldreich, Oded

    Concurrent Zero-Knowledge With Timing, Revisited Oded Goldreich Department of Computer Science-coming messages and delay out-going messages). We show that the constant-round zero-knowledge proof for NP zero-knowledge of interactive proofs, whereas the results of Dwork et. al. are either for zero

  8. Concurrent Zero-Knowledge With Timing, Revisited Oded Goldreich

    E-print Network

    Goldreich, Oded

    Concurrent Zero-Knowledge With Timing, Revisited Oded Goldreich Department of Computer Science-coming messages and delay out-going messages). We show that the constant-round zero-knowledge proof for NP to zero-knowledge of interactive proofs, whereas the results of Dwork et. al. are either for zero

  9. Special Relativity and Time Travel Revisited

    E-print Network

    Akhila Raman

    2001-01-25

    In this paper, Lorentz Transformation(LT) is derived by an alternate method, using photon clocks, placed at the locations of the concerned events, which are initially synchronised using a light signal(Einstein synchrony). Then, it is shown that the second term in the time dilation equation of the LT, is the term responsible for time travel and further it is shown that this term arises merely due to non-simultaneous initial clock synchronisation and that this term does not correspond to any actual time elapsed while timing events, thus ruling out the possibility of time travel, from the framework of special relativity. It is also shown that only the first term in the time dilation equation of LT represents the true time dilation. In other words, it is argued that the time dilation equation of the LT, corresponds to the actual reading of the clock which is not necessarily the actual time elapsed while timing an event, the difference being attributed to the clock synchronisation mechanism.

  10. Nonlinear time-series analysis revisited

    E-print Network

    Elizabeth Bradley; Holger Kantz

    2015-03-25

    In 1980 and 1981, two pioneering papers laid the foundation for what became known as nonlinear time-series analysis: the analysis of observed data---typically univariate---via dynamical systems theory. Based on the concept of state-space reconstruction, this set of methods allows us to compute characteristic quantities such as Lyapunov exponents and fractal dimensions, to predict the future course of the time series, and even to reconstruct the equations of motion in some cases. In practice, however, there are a number of issues that restrict the power of this approach: whether the signal accurately and thoroughly samples the dynamics, for instance, and whether it contains noise. Moreover, the numerical algorithms that we use to instantiate these ideas are not perfect; they involve approximations, scale parameters, and finite-precision arithmetic, among other things. Even so, nonlinear time-series analysis has been used to great advantage on thousands of real and synthetic data sets from a wide variety of systems ranging from roulette wheels to lasers to the human heart. Even in cases where the data do not meet the mathematical or algorithmic requirements to assure full topological conjugacy, the results of nonlinear time-series analysis can be helpful in understanding, characterizing, and predicting dynamical systems.

  11. Time Variability of Titan's Ionosphere Revisited

    NASA Astrophysics Data System (ADS)

    Hsu, Jen-Kai; Ip, Wing-Huen; Perryman, Rebecca; Waite, Hunter

    2015-04-01

    Since the Saturn Orbital Insertion in 2004, the Ion Neutral Mass Spectrometer (INMS) experiment aboard the Cassini-Huygens spacecraft has acquired an extensive data set. The decadal coverage of the measurements during numerous close encounters with Titan allows the study of spatial and temporal variations of Titan's nitrogen-rich atmosphere above 1000-km altitude. Titan's ionosphere is quite different to that of Earth's ionosphere. Due to Titan's thick (hundreds of kilometers) and dense atmosphere, the measurable ion density of Titan's nightside ionosphere extends well beyond the terminator. The diurnal variation of the ion density profiles and compositional changes are the result of photoionization and magnetospheric electron ionization (important at the night side). The different time evolutions of the light and heavy species from day to night could be indicative of the effects of flow dynamics and ion-molecule chemistry. From the observations, we can determine the ion content in Titan's night-side and the asymmetry between the dawn and dusk ion density profiles. We have also found in the long term data base the signature of the equatorial expansion of Titan's atmosphere during solar maximum. In addition the global distributions of the major compound N2 and minor species like CH4 and H2 all exhibit significant changes over a solar cycle as the closest approach points of Cassini moved from the northern hemisphere to the southern hemisphere. In this work, we will first compare the diurnal variations between different ion species and simulate the ion densities to study the possible contributing factors. Then we will compare the results of our analysis to those reported by other groups to construct a comprehensive model of Titan's neutral atmosphere and ionosphere under different solar conditions.

  12. Short-term retention of relational memory in amnesia revisited: accurate performance depends on hippocampal integrity

    PubMed Central

    Yee, Lydia T. S.; Hannula, Deborah E.; Tranel, Daniel; Cohen, Neal J.

    2014-01-01

    Traditionally, it has been proposed that the hippocampus and adjacent medial temporal lobe cortical structures are selectively critical for long-term declarative memory, which entails memory for inter-item and item-context relationships. Whether the hippocampus might also contribute to short-term retention of relational memory representations has remained controversial. In two experiments, we revisit this question by testing memory for relationships among items embedded in scenes using a standard working memory trial structure in which a sample stimulus is followed by a brief delay and the corresponding test stimulus. In each experimental block, eight trials using different exemplars of the same scene were presented. The exemplars contained the same items but with different spatial relationships among them. By repeating the pictures across trials, any potential contributions of item or scene memory to performance were minimized, and relational memory could be assessed more directly than has been done previously. When test displays were presented, participants indicated whether any of the item-location relationships had changed. Then, regardless of their responses (and whether any item did change its location), participants indicated on a forced-choice test, which item might have moved, guessing if necessary. Amnesic patients were impaired on the change detection test, and were frequently unable to specify the change after having reported correctly that a change had taken place. Comparison participants, by contrast, frequently identified the change even when they failed to report the mismatch, an outcome that speaks to the sensitivity of the change specification measure. These results confirm past reports of hippocampal contributions to short-term retention of relational memory representations, and suggest that the role of the hippocampus in memory has more to do with relational memory requirements than the length of a retention interval. PMID:24478681

  13. Universal short-time quantum critical dynamics in imaginary time

    NASA Astrophysics Data System (ADS)

    Yin, Shuai; Mai, Peizhi; Zhong, Fan

    2014-04-01

    We propose a scaling theory for the universal imaginary-time quantum critical dynamics for both short and long times. We discover that there exists a universal critical initial slip related to a small initial order parameter M0. In this stage, the order parameter M increases with the imaginary time ? as M ?M0?? with a universal initial-slip exponent ?. For the one-dimensional transverse-field Ising model, we estimate ? to be 0.373, which is markedly distinct from its classical counterpart. Apart from the local order parameter, we also show that the entanglement entropy exhibits universal behavior in the short-time region. As the critical exponents in the early stage and in equilibrium are identical, we apply the short-time dynamics method to determine quantum critical properties. The method is generally applicable in both the Landau-Ginzburg-Wilson paradigm and topological phase transitions.

  14. LINEAR TIME SPLIT DECOMPOSITION REVISITED PIERRE CHARBIT, FABIEN DE MONTGOLFIER, AND MATHIEU RAFFINOT

    E-print Network

    Paris-Sud XI, Université de

    LINEAR TIME SPLIT DECOMPOSITION REVISITED PIERRE CHARBIT, FABIEN DE MONTGOLFIER, AND MATHIEU RAFFINOT Abstract. Given a family F of subsets of a ground set V , its orthogonal is defined to be the fam of designing a simple linear time algorithm for undirected graph split (also known as 1-join) decomposition

  15. Short rise time intense electron beam generator

    DOEpatents

    Olson, C.L.

    1984-03-16

    A generator for producing an intense relativisitc electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.

  16. Why are very short times so long and very long times so short in elastic waves?

    E-print Network

    Parravicini, Guido

    2010-01-01

    In the study of elastic waves, physicists commonly understand that when the given period is very short, waves are isentropic because heat conduction does not set in, while if the given period is very long waves are isothermal because there is enough time for thermalization to be thoroughly accomplished. On the other hand, the mathematical inspection of the complete thermoelastic wave equation shows that if the period is very short, much shorter than a characteristic time of the material, the wave is isothermal, while if it is very long, much longer than the characteristic time, the wave is isentropic, a fact that is supported by experiments. The authors show that there is no contradiction between the physicists' understanding and the mathematical treatment of the elastic wave equation: for thermal effects very long periods are so short and very short periods are so long.

  17. DIVERGENCE TIMES AND THE EVOLUTION OF EPIPHYTISM IN FILMY FERNS (HYMENOPHYLLACEAE) REVISITED

    E-print Network

    Schuettpelz, Eric

    DIVERGENCE TIMES AND THE EVOLUTION OF EPIPHYTISM IN FILMY FERNS (HYMENOPHYLLACEAE) REVISITED Sabine and Science, 4-1-1 Amakubo, Tsukuba 305-0005, Japan Although the phylogeny of the filmy fern family to examine the diversification of filmy ferns and the evolution of their ecology within a temporal context

  18. Short echo time in vivo prostate 1H-MRSI

    Microsoft Academic Search

    Niranjan Venugopal; B. McCurdy; S. Al Mehairi; A. Alamri; G. S. Sandhu; S. Sivalingam; D. Drachenberg; L. Ryner

    Visualization of short echo time metabolites in prostate magnetic resonance spectroscopic imaging is difficult due to lipid contamination and pulse timing constraints. In this work we present a modified pulse sequence to permit short echo time (TE=40ms) acquisitions with reduced lipid contamination for the detection of short TE metabolites. The modified pulse sequence employs the conformal voxel MRS (CV-MRS) technique,

  19. Why are very short times so long and very long times so short in elastic waves?

    E-print Network

    Guido Parravicini; Serena Rigamonti

    2010-09-23

    In a first study of thermoelastic waves, such as on the textbook of Landau and Lifshitz, one might at first glance understand that when the given period is very short, waves are isentropic because heat conduction does not set in, while if the given period is very long waves are isothermal because there is enough time for thermalization to be thoroughly accomplished. When one pursues the study of these waves further, by the mathematical inspection of the complete thermoelastic wave equation he finds that if the period is very short, much shorter than a characteristic time of the material, the wave is isothermal, while if it is very long, much longer than the characteristic time, the wave is isentropic. One also learns that this fact is supported by experiments: at low frequencies the elastic waves are isentropic, while they are isothermal when the frequencies are so high that can be attained in few cases. The authors show that there is no contradiction between the first glance understanding and the mathematical treatment of the elastic wave equation: for thermal effects very long periods are so short and very short periods are so long.

  20. Revisiting Coincidence Rate between Gravitational Wave Detection and Short Gamma-Ray Burst for the Advanced and Third Generation

    NASA Astrophysics Data System (ADS)

    Regimbau, T.; Siellez, K.; Meacher, D.; Gendre, B.; Bor, M.

    2015-01-01

    We use realistic Monte Carlo simulations including both gravitational-wave (GW) and short gamma-ray burst (sGRB) selection effects to revisit the coincident rate of binary systems composed of two neutron stars or a neutron star and a black hole. We show that the fraction of GW triggers that can be observed in coincidence with sGRBs is proportional to the beaming factor at z = 0, but increases with the distance until it reaches 100% at the GW detector horizon distance. When this is taken into account the rate is improved by a factor of three compared to the simple beaming factor correction. We provide an estimate of the performance future GRB detectors should achieve in order to fully exploit the potentiality of the planned third-generation GW antenna Einstein Telescope, and we propose a simple method to constrain the beaming angle of sGRBs.

  1. Revisiting coincidence rate between Gravitational Wave detection and short Gamma-Ray Burst for the Advanced and third generation

    E-print Network

    Regimbau, T; Meacher, D; Gendre, B; er, M Bo\\"

    2014-01-01

    We use realistic Monte-Carlo simulations including both gravitational-wave and short gamma-ray burst selection effects to revisit the coincident rate of binary systems composed of two neutron stars or a neutron star and a black hole. We show that the fraction of GW triggers that can be observed in coincidence with sGRBs is proportional to the beaming factor at $z=0$, but increases with the distance, until it reaches 100 \\% at the GW detector horizon distance. When this is taken into account the rate is improved by a factor of $~3$ compared to the simple beaming factor correction. We provide an estimate of the performance future GRB detectors should achieve in order to fully exploit the potentiality of the planned third generation GW antenna Einstein Telescope, and we propose a simple method to constrain the beaming angle of sGRBs.

  2. Short-time Fourier analysis of sampled speech

    Microsoft Academic Search

    M. Portnoff

    1981-01-01

    The theoretical basis for the representation of a speech signal by its short-time Fourier transform is developed. A time-frequency representation for linear time-varying systems is applied to the speech-production model to formulate a quasi-stationary representation for the speech waveform. Short-time Fourier analysis of the resulting representation yields the relationship between the short-time Fourier transform of the speech and the speech-production

  3. Continuous-time linear programming problems revisited: A perturbation approach

    Microsoft Academic Search

    Hsien-Chung Wu

    2011-01-01

    The class of continuous-time linear programming problems under the assumption that the constraints are satisfied almost everywhere in the time interval [0,?T]?is taken into account in this article. Under this assumption, its corresponding discretized problems cannot be formulated by equally dividing the time interval [0,?T]?as subintervals of [0,?T]?. In this article, we also introduce the perturbed continuous-time linear programming problems

  4. A Short Time Beltrami Kernel for Smoothing Images and Manifolds

    E-print Network

    Kimmel, Ron

    A Short Time Beltrami Kernel for Smoothing Images and Manifolds Alon Spira, Ron Kimmel, Senior Member, IEEE, and Nir Sochen Abstract We introduce a short time kernel for the Beltrami image enhancing of the Beltrami flow and shows that the bilateral filter is a Euclidean approximation of it. On a practical level

  5. ``Sometimes'' and ``Not Never'' Revisited: On Branching Versus Linear Time

    Microsoft Academic Search

    E. Allen Emerson; Joseph Y. Halpern

    1983-01-01

    Temporal logic ([PR57], [PR67]) provides a formalism fordescribing the occurrence of events in time which is suitable forreasoning about concurrent programs (cf. [PN77]). In definingtemporal logic, there are two possible views regarding theunderlying nature of time. One is that time is linear: at eachmoment there is only one possible future. The other is that timehas a branching, tree-like nature: at

  6. Distant healing revisited: time for a new epistemology.

    PubMed

    Koopman, Barbara G; Blasband, Richard A

    2002-01-01

    As distant healing becomes a valid object of scientific scrutiny, state-of-the-art statistical techniques point to outcomes clearly outside the realm of chance. Accordingly, a variety of experimental designs have come into play that highlight the many challenges and hazards of trying to objectify conscious intention. Our survey pinpoints some landmark studies geared toward relatively modest, short-term healing through the application of multiple modalities. In view of the transient and modest results of the distant healing reported, we suggest that the full range of its potential and its longitudinal effects have yet to be uncovered. To this end, we believe that broader, nonlinear thought processes would better serve us in fathoming the mysterious leap from mind to living matter. PMID:11795608

  7. The Demise of Short-Term Memory Revisited: Empirical and Computational Investigations of Recency Effects

    Microsoft Academic Search

    Eddy J. Davelaar; Yonatan Goshen-Gottstein; Amir Ashkenazi; Henk J. Haarmann; Marius Usher

    2005-01-01

    In the single-store model of memory, the enhanced recall for the last items in a free-recall task (i.e., the recency effect) is understood to reflect a general property of memory rather than a separate short-term store. This interpretation is supported by the finding of a long-term recency effect under conditions that eliminate the contribution from the short-term store. In this

  8. Escape or switching at short times

    NASA Astrophysics Data System (ADS)

    Grinstein, G.; Koch, R. H.

    2005-10-01

    In the standard Arrhenius picture [S. Arrhenius, Z. Phys. Chem., Stoechiom. Verwandtschaftsl. 4, 226 (1889); L. Nel, Ann. Geophys. (C.N.R.S.) 5, 99 (1949)] of thermal switching or escape from a metastable to a stable state, the escape probability per unit time Ps(t) decreases monotonically with time t as Ps(t)e-t/?D , where the decay time ?D=?0eU/kBT , with U the energy barrier, kBT the thermal energy, and ?0 the time between escape attempts. Here, we extend the Arrhenius picture to shorter times by deriving general conditions under which Ps(t) is peaked rather than monotonic, and showing that in the simplest scenario the peak time ?P diverges with ?D as ln(?D) .

  9. Short time-series microarray analysis: methods and challenges.

    PubMed

    Wang, Xuewei; Wu, Ming; Li, Zheng; Chan, Christina

    2008-01-01

    The detection and analysis of steady-state gene expression has become routine. Time-series microarrays are of growing interest to systems biologists for deciphering the dynamic nature and complex regulation of biosystems. Most temporal microarray data only contain a limited number of time points, giving rise to short-time-series data, which imposes challenges for traditional methods of extracting meaningful information. To obtain useful information from the wealth of short-time series data requires addressing the problems that arise due to limited sampling. Current efforts have shown promise in improving the analysis of short time-series microarray data, although challenges remain. This commentary addresses recent advances in methods for short-time series analysis including simplification-based approaches and the integration of multi-source information. Nevertheless, further studies and development of computational methods are needed to provide practical solutions to fully exploit the potential of this data. PMID:18605994

  10. Analysis of fMRI Time-Series Revisited - Again

    Microsoft Academic Search

    K. J. Worsley; K. J. Friston

    1997-01-01

    Friston et al. (1995) presented a method for detecting activations in fMRI time-series based on the general linear model and a heuristic analysis of the efiective degrees of free- dom. In this communication we present corrected results that replace those of the previous paper and solve the same problem without recourse to heuristic arguments. Speciflcally we introduce a proper and

  11. Analysis of fMRI Time-Series Revisited

    Microsoft Academic Search

    K. J. Friston; A. P. Holmes; J. B. Poline; P. J. Grasby; S. C. R. Williams; R. S. J. Frackowiak; R. Turner

    1995-01-01

    This paper presents a general approach to the analysis of functional MRI time-series from one or more subjects. The approach is predicated on an extension of the general linear model that allows for correlations between error terms due to physiological noise or correlations that ensue after temporal smoothing. This extension uses the effective degrees of freedom associated with the error

  12. Freely floating structures trapping time-harmonic water waves (revisited)

    E-print Network

    Nikolay Kuznetsov; Oleg Motygin

    2014-10-22

    We study the coupled small-amplitude motion of the mechanical system consisting of infinitely deep water and a structure immersed in it. The former is bounded above by a free surface, whereas the latter is formed by an arbitrary finite number of surface-piercing bodies floating freely. The mathematical model of time-harmonic motion is a spectral problem in which the frequency of oscillations serves as the spectral parameter. It is proved that there exist axisymmetric structures consisting of $N \\geq 2$ bodies; every structure has the following properties: (i) a time-harmonic wave mode is trapped by it; (ii) some of its bodies (may be none) are motionless, whereas the rest of the bodies (may be none) are heaving at the same frequency as water. The construction of these structures is based on a generalization of the semi-inverse procedure applied earlier for obtaining trapping bodies that are motionless although float freely.

  13. The multi-configurational time-dependent Hartree approach revisited.

    PubMed

    Manthe, Uwe

    2015-06-28

    The multi-configurational time-dependent Hartree (MCTDH) approach facilitates accurate high-dimensional quantum dynamics simulations. In the approach, the wavefunction is expanded in a direct product of self-adapting time-dependent single-particle functions (SPFs). The equations of motion for the expansion coefficients and the SPFs are obtained via the Dirac-Frenkel variational principle. While this derivation yields well-defined differential equations for the motion of occupied SPFs, singularities in the working equations resulting from unoccupied SPFs have to be removed by a regularization procedure. Here, an alternative derivation of the MCTDH equations of motion is presented. It employs an analysis of the time-dependence of the single-particle density matrices up to second order. While the analysis of the first order terms yields the known equations of motion for the occupied SPFs, the analysis of the second order terms provides new equations which allow one to identify optimal choices for the unoccupied SPFs. The effect of the optimal choice of the unoccupied SPFs on the structure of the MCTDH equations of motion and their regularization is discussed. Generalized equations applicable in the multi-layer MCTDH framework are presented. Finally, the effects resulting from the initial choice of the unoccupied SPFs are illustrated by a simple numerical example. PMID:26133412

  14. Short-time Dynamic Behaviour of Critical XY Systems

    E-print Network

    H. J. Luo; M. Schulz; L. Schuelke; S. Trimper; B. Zheng

    1998-12-08

    Using Monte Carlo methods, the short-time dynamic scaling behaviour of two-dimensional critical XY systems is investigated. Our results for the XY model show that there exists universal scaling behaviour already in the short-time regime, but the values of the dynamic exponent $z$ differ for different initial conditions. For the fully frustrated XY model, power law scaling behaviour is also observed in the short-time regime. However, a violation of the standard scaling relation between the exponents is detected.

  15. Revisiting the Central Dogma One Molecule at a Time

    PubMed Central

    Bustamante, Carlos; Cheng, Wei; Meija, Yara

    2011-01-01

    The faithful relay and timely expression of genetic information depend on specialized molecular machines, many of which function as nucleic acid translocases. The emergence over the last decade of single-molecule fluorescence detection and manipulation techniques with nm and resolution, and their application to the study of nucleic acid translocases are painting an increasingly sharp picture of the inner workings of these machines, the dynamics and coordination of their moving parts, their thermodynamic efficiency, and the nature of their transient intermediates. Here we present an overview of the main results arrived at by the application of single-molecule methods to the study of the main machines of the central dogma. PMID:21335233

  16. Controlled short residence time coal liquefaction process

    DOEpatents

    Anderson, Raymond P. (Overland Park, KS); Schmalzer, David K. (Englewood, CO); Wright, Charles H. (Overland Park, KS)

    1982-05-04

    Normally solid dissolved coal product and a distillate liquid product are produced by continuously passing a feed slurry comprising raw feed coal and a recycle solvent oil and/or slurry together with hydrogen to a preheating-reaction zone (26, alone, or 26 together with 42), the hydrogen pressure in the preheating-reaction zone being at least 1500 psig (105 kg/cm.sup.2), reacting the slurry in the preheating-reaction zone (26, or 26 with 42) at a temperature in the range of between about 455.degree. and about 500.degree. C. to dissolve the coal to form normally liquid coal and normally solid dissolved coal. A total slurry residence time is maintained in the reaction zone ranging from a finite value from about 0 to about 0.2 hour, and reaction effluent is continuously and directly contacted with a quenching fluid (40, 68) to substantially immediately reduce the temperature of the reaction effluent to below 425.degree. C. to substantially inhibit polymerization so that the yield of insoluble organic matter comprises less than 9 weight percent of said feed coal on a moisture-free basis. The reaction is performed under conditions of temperature, hydrogen pressure and residence time such that the quantity of distillate liquid boiling within the range C.sub.5 -455.degree. C. is an amount at least equal to that obtainable by performing the process under the same conditions except for a longer total slurry residence time, e.g., 0.3 hour. Solvent boiling range liquid is separated from the reaction effluent and recycled as process solvent.

  17. Nuclear Winter Revisited: can it Make a Difference This Time?

    NASA Astrophysics Data System (ADS)

    Schneider, S.

    2006-12-01

    Some 23 years ago, in the middle of a Cold War and the threat of a strategic nuclear weapons exchange between NATO and the Warsaw Pact nations, atmospheric scientists pointed out that the well-anticipated side effects of a large-scale nuclear war ozone depletion, radioactive contamination and some climatic effects had massively underestimated the more likely implications: massive fires, severe dimming and cooling beneath circulating smoke clouds, disruption to agriculture in non-combatant nations, severe loss of imports of food to already-food-deficient regions and major alterations to atmospheric circulation. While the specific consequences were dependent on both scenarios of weapons use and injections and removals of smoke and dust and other chemicals into the atmosphere, it was clear that this would be despite passionately argued uncertainties a large major additional effect. As further investigations of smoke removal, patchy transport, etc., were pursued, the basic concerns remained, but the magnitude calculated with one-dimensional models diminished creating an unfortunate media debate over nuclear winter vs. nuclear autumn. Of course, one can't grow summer crops in any autumn natural or nuclear but that concern often got lost in the contentious political debate. Of course, it was pointed out that anyone who required knowing the additional environmental consequences of a major nuclear exchange to be finally deterred was already so far from the reality of the direct effects of the blasts that they might never see the concerns. But for non-combatants, it was a major awakening of their inability to escape severe consequences of the troubles of others, even if they were bystanders in the east-west conflicts. Two decades later, things have radically changed: the prospect of a massive strategic nuclear exchange is greatly diminished good news but the possibility of limited regional exchanges or terrorist incidents is widely believed to have greatly increased bad news. Therefore, the re- examination in this AGU session of the entire subject of environmental and social after-effects of any nuclear weapons use is, unfortunately, once again timely. Hopefully it will convince anyone not already convinced based on conventional damages from nuclear weapons use of the urgent need to abate proliferation and monitor and control access to and potential capabilities of those who might contemplate using such weapons for some Strangelove-like strategic or ideological objective. The extent to which a scientific re-examination of the broader horrendous implications of any scale of use of nuclear weapons will deter those contemplating their use is questionable. However, it seems likely such research would increase the resolve of the large number of countries and institutions already pressing to prevent nuclear weapons use.

  18. Market volatility modeling for short time window

    NASA Astrophysics Data System (ADS)

    de Mattos Neto, Paulo S. G.; Silva, David A.; Ferreira, Tiago A. E.; Cavalcanti, George D. C.

    2011-10-01

    The gain or loss of an investment can be defined by the movement of the market. This movement can be estimated by the difference between the magnitudes of two stock prices in distinct periods and this difference can be used to calculate the volatility of the markets. The volatility characterizes the sensitivity of a market change in the world economy. Traditionally, the probability density function (pdf) of the movement of the markets is analyzed by using power laws. The contributions of this work is two-fold: (i) an analysis of the volatility dynamic of the world market indexes is performed by using a two-year window time data. In this case, the experiments show that the pdf of the volatility is better fitted by exponential function than power laws, in all range of pdf; (ii) after that, we investigate a relationship between the volatility of the markets and the coefficient of the exponential function based on the Maxwell-Boltzmann ideal gas theory. The results show an inverse relationship between the volatility and the coefficient of the exponential function. This information can be used, for example, to predict the future behavior of the markets or to cluster the markets in order to analyze economic patterns.

  19. The scaling of premarital sexual permissiveness revisited: test results of Reiss's new short form version.

    PubMed

    Schwartz, I M; Reiss, I L

    1995-01-01

    A new four-item version of the widely used Reiss Premarital Sexual Permissiveness (PSP) Scale is described and analyzed. The purpose of our research was to see if this much quicker to answer format will equal the high scaling attributes of the earlier and longer versions. Samples of students from the United States (N = 217) and Sweden (N = 186) were administered the short form. The analysis and data are presented and compared with the results of the original, longer versions of the scale. Results indicated that the four-item version met all Guttman scale requirements. Comparisons among scales indicated that criteria measurement scores were higher for the four-item version than they were for Reiss's earlier versions. The ways in which the new scale may be used are discussed, including the possible use of only one or two items from this new format as a quick and accurate attitudinal assessment of premarital sexual permissiveness. PMID:7643425

  20. A Security Analysis of the Precise Time Protocol (Short Paper)

    E-print Network

    existing protocols such as the Network Time Protocol (NTP) [7] and the Global Positioning System (GPS-microsecond level for small self-administered networks [4,5]. NTP also requires the underlying network to be IPA Security Analysis of the Precise Time Protocol (Short Paper) Jeanette Tsang and Konstantin

  1. Sco X-1 revisited with Kepler, MAXI and HERMES: outflows, time-lags and echoes unveiled

    E-print Network

    Scaringi, S; Hynes, R I; Koerding, E; Ponti, G; Knigge, C; Britt, C T; van Winckel, H

    2015-01-01

    Sco X-1 has been the subject of many multi-wavelength studies in the past, being the brightest persistent extra-solar X-ray source ever observed. Here we revisit Sco X-1 with simultaneous short cadence Kepler optical photometry and MAXI X-ray photometry over a 78 day period, as well as optical spectroscopy obtained with HERMES. We find Sco X-1 to be highly variable in all our datasets. The optical fluxes are clearly bimodal, implying the system can be found in two distinct optical states. These states are generally associated with the known flaring/normal branch X-ray states, although the flux distributions associated with these states overlap. Furthermore, we find that the optical power spectrum of Sco X-1 differs substantially between optical luminosity states. Additionally we find rms-flux relations in both optical states, but only find a linear relation during periods of low optical luminosity. The full optical/X-ray discrete correlation function displays a broad ~12.5 hour optical lag. However during the...

  2. Signal reconstruction from short-time Fourier transform magnitude

    Microsoft Academic Search

    S. Nawab; THOMAS F. QUATIERI; JAE S. LIM

    1983-01-01

    In this paper, a signal is shown to be uniquely represented by the magnitude of its short-time Fourier transform (STFT) under mild restrictions on the signal and the analysis window of the STFT. Furthermore, various algorithms are developed which reconstruct signal from appropriate samples of the STFT magnitude. Several of the algorithms can also be used to obtain signal estimates

  3. Comparison of high power short time flywheel storage systems

    Microsoft Academic Search

    H. Darrelmann

    1999-01-01

    Uninterruptible power supply (UPS) systems are supported mainly by batteries to cover short network breakdowns. The advantages of batteries in this application are their high degree of modularisation, low charging regime losses and not least their wide spread availability. Disadvantages are their weight, high maintenance costs and their high price if storage times of less than one minute are desired

  4. Ecient Beltrami Flow using a Short Time Kernel

    E-print Network

    Kimmel, Ron

    Ecient Beltrami Flow using a Short Time Kernel A. Spira 1 , R. Kimmel 1 , and N. Sochen 2 1 for the Beltrami image enhancing ow. The ow is implemented by `convolving' the image with a space dependent kernel. The expression for the kernel shows, yet again, the connection between the Beltrami ow

  5. Rules extraction in short memory time series using genetic algorithms

    NASA Astrophysics Data System (ADS)

    Fong, L. Y.; Szeto, K. Y.

    2001-04-01

    Data mining is performed using genetic algorithm on artificially generated time series data with short memory. The extraction of rules from a training set and the subsequent testing of these rules provide a basis for the predictions on the test set. The artificial time series are generated using the inverse whitening transformation, and the correlation function has an exponential form with given time constant indicative of short memory. A vector quantization technique is employed to classify the daily rate of return of this artificial time series into four categories. A simple genetic algorithm based on a fixed format of rules is introduced to do the forecasting. Comparing to the benchmark tests with random walk and random guess, genetic algorithms yield substantially better prediction rates, between 50% to 60%. This is an improvement compared with the 47% for random walk prediction and 25% for random guessing method.

  6. Modelling the short-time response of ISFET sensors

    Microsoft Academic Search

    P. Woias; L. Meixner; D. Amandi; M. Schnberger

    1995-01-01

    In this publication, a model for the short-time response of ISFET sensors is presented. In contrast to the static site-binding theory, this approach takes into account the kinetics of the electrochemical reactions occurring on the gate-insulator surface. As a result, a system of coupled non-linear differential equations is formulated, which is able to describe the pH-step response of an ISFET

  7. Statistics of short time variations of indoor radio propagation

    Microsoft Academic Search

    Rajamani Ganesh; Kaveh Pahlavan

    1991-01-01

    In an indoor environment, channel variations which occur most frequently are due to the movement of personnel near the transmitting or receiving antennas and\\/or local movements of the terminals around a given location. Such short-time variations in the indoor radio channel are studied and determined by performing propagation experiments in line-of-sight and non-line-of-sight environments at 910 MHz. The database is

  8. Short-time dynamics of charge-stabilized colloidal suspensions

    Microsoft Academic Search

    Gerhard Ngele; Barbara Steininger; Ulrike Genz; Rudolf Klein

    1994-01-01

    We have calculated the combined effects of the electrostatic and hydrodynamic interactions on the short-time dynamics of charge-stabilized colloidal suspensions, which can be investigated experimentally from the first cumulant of the dynamic scattering function. The first cumulant is obtained using two methods, a pairwise-additivity approximation for the many-body hydrodynamic interaction combined with a far-field expansion of the mobility tensors, and

  9. Short-time scale behavior modeling within long-time scale fuel cycle evaluations

    SciTech Connect

    Johnson, M.; Tsvetkov, P. [Dept. of Nuclear Engineering, Texas A and M Univ., 3133 TAMU, College Station, TX 77843 (United States); Lucas, S. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415 (United States)

    2012-07-01

    Typically, short-time and long-time scales in nuclear energy system behavior are accounted for with entirely separate models. However, long-term changes in system characteristics do affect short-term transients through material variations. This paper presents an approach to consistently account for short-time scales within a nuclear system lifespan. The reported findings and developments are of significant importance for small modular reactors and other nuclear energy systems operating in autonomous modes. It is necessary to simulate the short time-scale kinetic behavior of the reactor as well as the long time-scale dynamics that occur with fuel burnup. The former is modeled using the point kinetics equations, while the latter is modeled by the Bateman equations. (authors)

  10. Orphan drugs for rare diseases: is it time to revisit their special market access status?

    PubMed

    Simoens, Steven; Cassiman, David; Dooms, Marc; Picavet, Eline

    2012-07-30

    Orphan drugs are intended for diseases with a very low prevalence, and many countries have implemented legislation to support market access of orphan drugs. We argue that it is time to revisit the special market access status of orphan drugs. Indeed, evidence suggests that there is no societal preference for treating rare diseases. Although society appears to assign a greater value to severity of disease, this criterion is equally relevant to many common diseases. Furthermore, the criterion of equity in access to treatment, which underpins orphan drug legislation, puts more value on health improvement in rare diseases than in common diseases and implies that population health is not maximized. Finally, incentives for the development, pricing and reimbursement of orphan drugs have created market failures, including monopolistic prices and the artificial creation of rare diseases. We argue that, instead of awarding special market access status to orphan drugs, there is scope to optimize research and development (R&D) of orphan drugs and to control prices of orphan drugs by means of, for example, patent auctions, advance purchase commitments, pay-as-you-go schemes and dose-modification studies. Governments should consider carefully the right incentive strategy for R&D of orphan drugs in rare diseases. PMID:22747423

  11. Short-time dynamics of permeable particles in concentrated suspensions.

    PubMed

    Abade, Gustavo C; Cichocki, Bogdan; Ekiel-Jezewska, Maria L; Ngele, Gerhard; Wajnryb, Eligiusz

    2010-01-01

    We study short-time diffusion properties of colloidal suspensions of neutral permeable particles. An individual particle is modeled as a solvent-permeable sphere of interaction radius a and uniform permeability k, with the fluid flow inside the particle described by the Debye-Bueche-Brinkman equation, and outside by the Stokes equation. Using a precise multipole method and the corresponding numerical code HYDROMULTIPOLE that account for higher-order hydrodynamic multipole moments, numerical results are presented for the hydrodynamic function, H(q), the short-time self-diffusion coefficient, D(s), the sedimentation coefficient K, the collective diffusion coefficient, D(c), and the principal peak value H(q(m)), associated with the short-time cage diffusion coefficient, as functions of porosity and volume fraction. Our results cover the full fluid phase regime. Generic features of the permeable sphere model are discussed. An approximate method by Pusey to determine D(s) is shown to agree well with our accurate results. It is found that for a given volume fraction, the wavenumber dependence of a reduced hydrodynamic function can be estimated by a single master curve, independent of the particle permeability, given by the hard-sphere model. The reduced form is obtained by an appropriate shift and rescaling of H(q), parametrized by the self-diffusion and sedimentation coefficients. To improve precision, another reduced hydrodynamic function, h(m)(q), is also constructed, now with the self-diffusion coefficient and the peak value, H(q(m)), of the hydrodynamic function as the parameters. For wavenumbers qa>2, this function is permeability independent to an excellent accuracy. The hydrodynamic function of permeable particles is thus well represented in its q-dependence by a permeability-independent master curve, and three coefficients, D(s), K, and H(q(m)), that do depend on the permeability. The master curve and its coefficients are evaluated as functions of concentration and permeability. PMID:20078168

  12. Desensitization to media violence over a short period of time.

    PubMed

    Fanti, Kostas A; Vanman, Eric; Henrich, Christopher C; Avraamides, Marios N

    2009-01-01

    This study investigated the desensitization to violence over a short period of time. Participants watched nine violent movie scenes and nine comedy scenes, and reported whether they enjoyed the violent or comedy scenes and whether they felt sympathetic toward the victim of violence. Using latent growth modeling, analyses were carried out to investigate how participants responded to the different scenes across time. The findings of this study suggested that repeated exposure to media violence reduces the psychological impact of media violence in the short term, therefore desensitizing viewers to media violence. As a result, viewers tended to feel less sympathetic toward the victims of violence and actually enjoy more the violence portrayed in the media. Additionally, desensitization to media violence was better represented by a curvilinear pattern, whereas desensitization to comedy scenes was better represented by a linear pattern. Finally, trait aggression was not related to the pattern of change over time, although significant effects were found for initial reports of enjoyment and sympathy. PMID:19172659

  13. Short time die attach characterisation of semiconductor devices

    E-print Network

    P. Szabo; M. Rencz

    2008-01-07

    Thermal qualification of the die attach of semiconductor devices is a very important element in the device characterization as the temperature of the chip is strongly affected by the quality of the die attach. Voids or delaminations in this layer may cause higher temperature elevation and thus damage or shorter lifetime. Thermal test of each device in the manufacturing process would be the best solution for eliminating the devices with wrong die attach layer. In this paper we will present the short time thermal transient measurement method and the structure function evaluation through simulations and measurements for die attach characterization. We will also present a method for eliminating the very time consuming calibration process. Using the proposed methods even the in-line testing of LEDs can be accomplished.

  14. Short- and Long- Time Transport Structures in a Three Dimensional Time Dependent Flow

    E-print Network

    Rodolphe Chabreyrie; Stefan G. Llewellyn Smith

    2014-05-08

    Lagrangian transport structures for three-dimensional and time-dependent fluid flows are of great interest in numerous applications, particularly for geophysical or oceanic flows. In such flows, chaotic transport and mixing can play important environmental and ecological roles, for examples in pollution spills or plankton migration. In such flows, where simulations or observations are typically available only over a short time, understanding the difference between short-time and long-time transport structures is critical. In this paper, we use a set of classical (i.e. Poincar\\'e section, Lyapunov exponent) and alternative (i.e. finite time Lyapunov exponent, Lagrangian coherent structures) tools from dynamical systems theory that analyze chaotic transport both qualitatively and quantitatively. With this set of tools we are able to reveal, identify and highlight differences between short- and long-time transport structures inside a flow composed of a primary horizontal contra-rotating vortex chain, small lateral oscillations and a weak Ekman pumping. The difference is mainly the existence of regular or extremely slowly developing chaotic regions that are only present at short time.

  15. Short- and Long- Time Transport Structures in a Three Dimensional Time Dependent Flow

    NASA Astrophysics Data System (ADS)

    Chabreyrie, Rodolphe; Llewellyn Smith, Stefan

    2012-11-01

    Lagrangian transport structures for three-dimensional and time-dependent fluid flows are of great interest in numerous applications, particularly for geophysical or oceanic flows. In such flows, chaotic transport and mixing can play important environmental and ecological roles, for examples in pollution spills or plankton migration. In such flows, where simulations or observations are typically available only over a short time, understanding the difference between short-time and long-time transport structures is critical. In this talk, we use a set of classical (i.e. Poincar section, Lyapunov exponent) and alternative (i.e. finite time Lyapunov exponent, Lagrangian coherent structures) tools from dynamical systems theory that analyze chaotic transport both qualitatively and quantitatively. With this set of tools we are able to reveal, identify and highlight differences between short- and long-time transport structures inside a flow composed of a primary horizontal contra-rotating vortex chain, small lateral oscillations and a weak Ekman pumping. The difference is mainly the existence of regular or extremely slowly developing chaotic regions that are only present at short time. This research was funded by the ONR MURI Dynamical Systems Theory and Lagrangian Data Assimilation in 3D+1 Geophysical Fluid Dynamics.

  16. Entry velocities at Mars and Earth for short transit times

    NASA Astrophysics Data System (ADS)

    Finke, Reinald G.

    1993-07-01

    Propulsion systems composed of a Shuttle External Tank, appropriately modified for the purpose, with a rocket engine that is either an SSME or a NERVA could inject a gross personnel payload of 100,000 lb on a trans-Mars trajectory from Space Station Freedom with aerobraking at Mars with transit times of less that 70 days. Such transit times reflect a significant reduction from the 200-plus days generally considered. The 100,000-lb payload would include the mass of a hypothetical aerobrake for aerocapture at Mars. The entry velocities at Mars compatible with such transit times are greater that 21 km/sec, to be compared with previously stated constraints of 8.5 to 9.5 km/sec for nominal Mars entry velocity. Limits of current aerobrake technology are not well enough defined to determine the feasibility of an aerobrake to handle Mars-entry velocities for short-transit-time trajectories. Return from Mars to Earth on a mirror image of 70-days outbound trajectory (consistent with a stay time of about 12 days) would require a Mars-departure velocity increment more than twice as great as that at Earth departure and would require a correspondingly more capable propulsion system. The return propulsion system would preferably be pre-deployed at Mars by one or more separate minimum-energy, 0.5 to 1.1 Mlb gross payload cargo flights with the same outbound propulsion systems as the personnel flight, before commitment of the personnel flight. Aerobraking entry velocity at Earth after such a transit time would be about 16 km/sec, to be compared with constraints set at 12.5 to 16 km/sec.

  17. An Incremental Algorithm for Signal Reconstruction from Short-Time Fourier Transform Magnitude

    E-print Network

    Poggio, Tomaso

    An Incremental Algorithm for Signal Reconstruction from Short-Time Fourier Transform Magnitude Jake@mit.edu Abstract We present an algorithm for reconstructing a time-domain signal from the magnitude of a short-domain signal from only the magnitude of the short-time Fourier transform (STFT) is a common prob- lem in speech

  18. Ultra short-time dynamics of radiation damage in fcc metals Marc Hayoun1

    E-print Network

    Boyer, Edmond

    1 / 15 Ultra short-time dynamics of radiation damage in fcc metals Marc Hayoun1 , Gerrit Coddens in copper in order to investigate the non-equilibrium ultra-short time damage and to evaluate in the X-ray intensities at ultra-short times is an important alteration of the lattice vibrations

  19. Deterministic Polynomial-Time Algorithms for Designing Short DNA Words

    E-print Network

    Kao, Ming-Yang; Sun, He; Zhang, Yong

    2012-01-01

    Designing short DNA words is a problem of constructing a set (i.e., code) of n DNA strings (i.e., words) with the minimum length such that the Hamming distance between each pair of words is at least k and the n words satisfy a set of additional constraints. This problem has applications in, e.g., DNA self-assembly and DNA arrays. Previous works include those that extended results from coding theory to obtain bounds on code and word sizes for biologically motivated constraints and those that applied heuristic local searches, genetic algorithms, and randomized algorithms. In particular, Kao, Sanghi, and Schweller (2009) developed polynomial-time randomized algorithms to construct n DNA words of length within a multiplicative constant of the smallest possible word length (e.g., 9 max{log n, k}) that satisfy various sets of constraints with high probability. In this paper, we give deterministic polynomial-time algorithms to construct DNA words based on derandomization techniques. Our algorithms can construct n DN...

  20. Short-time vibrational dynamics of metaphosphate glasses

    NASA Astrophysics Data System (ADS)

    Kalampounias, Angelos G.

    2012-02-01

    In this paper we present the picosecond vibrational dynamics of a series of binary metaphosphate glasses, namely Na2O-P2O5, MO-P2O5 (M=Ba, Sr, Ca, Mg) and Al2O3-3P2O5 by means of Raman spectroscopy. We studied the vibrational dephasing and vibrational frequency modulation by calculating time correlation functions of vibrational relaxation by fits in the frequency domain. The fitting method used enables one to model the real line profiles intermediate between Lorentzian and Gaussian by an analytical function, which has an analytical counterpart in the time domain. The symmetric stretching modes ?s(PO2-) and ?s(P-O-P) of the PO2- entity of P2O2- units and of P-O-P bridges in metaphosphate arrangements have been investigated by Raman spectroscopy and we used them as probes of the dynamics of these glasses. The vibrational time correlation functions of both modes studied are rather adequately interpreted within the assumption of exponential modulation function in the context of Kubo-Rothschield theory and indicate that the system experiences an intermediate dynamical regime that gets only slower with an increase in the ionic radius of the cation-modifier. We found that the vibrational correlation functions of all glasses studied comply with the Rothschild approach assuming that the environmental modulation is described by a stretched exponential decay. The evolution of the dispersion parameter ? with increasing ionic radius of the cation indicates the deviation from the model simple liquid indicating the reduction of the coherence decay in the perturbation potential as a result of local short lived aggregates. The results are discussed in the framework of the current phenomenological status of the field.

  1. Variations in solar Lyman alpha irradiance on short time scales

    NASA Technical Reports Server (NTRS)

    Pap, J. M.

    1992-01-01

    Variations in solar UV irradiance at Lyman alpha are studied on short time scales (from days to months) after removing the long-term changes over the solar cycle. The SME/Lyman alpha irradiance is estimated from various solar indices using linear regression analysis. In order to study the nonlinear effects, Lyman alpha irradiance is modeled with a 5th-degree polynomial as well. It is shown that the full-disk equivalent width of the He line at 1083 nm, which is used as a proxy for the plages and active network, can best reproduce the changes observed in Lyman alpha. Approximately 72 percent of the solar-activity-related changes in Lyman alpha irradiance arise from plages and the network. The network contribution is estimated by the correlation analysis to be about 19 percent. It is shown that significant variability remains in Lyman alpha irradiance, with periods around 300, 27, and 13.5d, which is not explained by the solar activity indices. It is shown that the nonlinear effects cannot account for a significant part of the unexplained variation in Lyman alpha irradiance. Therefore, additional events (e.g., large-scale motions and/or a systematic difference in the area and intensity of the plages and network observed in the lines of Ca-K, He 1083, and Lyman alpha) may explain the discrepancies found between the observed and estimated irradiance values.

  2. Short time-scale periodicity in OJ 287

    NASA Astrophysics Data System (ADS)

    Pihajoki, P.; Valtonen, M.; Ciprini, S.

    2013-10-01

    We have studied short-term variations of the blazar OJ 287, suspected to host a supermassive black hole binary. In this study, we use a two-season optical R-band data set from 2004 to 2006 which consists of 3991 data points from the OJ 287 observation campaign. It has sections of dense time coverage, and is largely independent from previously published data. We find that these data confirm the existence of a 50 d periodic component, presumably related to the half-period of the innermost stable circular orbit (ISCO) of the primary black hole. In addition, we find several pseudo-periodic components in the 1-7 d range, most prominently at 3.5 d, which are likely Lorentz contracted jet re-emission of the 50 d component. The typical 50-d cycle exhibits a slow rise of brightness and a rapid dimming before the start of the new cycle. We explain this as being due to a spiral wave in the accretion disc which feeds the central black hole in this manner.

  3. Short Boys Three Times More Likely to Get Growth Hormone

    MedlinePLUS

    ... so growth failure merits equal consideration for both boys and girls," study leader Dr. Adda Grimberg, a pediatric endocrinologist ... in treatment may have doubly undesirable effects -- short girls who have an ... boys may receive overzealous, unnecessary treatment with an expensive ...

  4. Time-resolved diffraction profiles and structural dynamics of Ni film under short laser pulse irradiation

    E-print Network

    Zhigilei, Leonid V.

    transformations induced in a thin Ni film by short pulse laser irradiation is investigated in molecular dynamicsTime-resolved diffraction profiles and structural dynamics of Ni film under short laser pulse. Introduction Short (pico- and femtosecond) pulse laser irradiation has the ability to bring material

  5. Epileptic seizure classification of EEG time-series using rational discrete short-time fourier transform.

    PubMed

    Samiee, Kaveh; Kovcs, Petr; Gabbouj, Moncef

    2015-02-01

    A system for epileptic seizure detection in electroencephalography (EEG) is described in this paper. One of the challenges is to distinguish rhythmic discharges from nonstationary patterns occurring during seizures. The proposed approach is based on an adaptive and localized time-frequency representation of EEG signals by means of rational functions. The corresponding rational discrete short-time Fourier transform (DSTFT) is a novel feature extraction technique for epileptic EEG data. A multilayer perceptron classifier is fed by the coefficients of the rational DSTFT in order to separate seizure epochs from seizure-free epochs. The effectiveness of the proposed method is compared with several state-of-art feature extraction algorithms used in offline epileptic seizure detection. The results of the comparative evaluations show that the proposed method outperforms competing techniques in terms of classification accuracy. In addition, it provides a compact representation of EEG time-series. PMID:25265603

  6. SHORT COMMUNICATION: Time measurement device with four femtosecond stability

    NASA Astrophysics Data System (ADS)

    Panek, Petr; Prochazka, Ivan; Kodet, Jan

    2010-10-01

    We present the experimental results of extremely precise timing in the sense of time-of-arrival measurements in a local time scale. The timing device designed and constructed in our laboratory is based on a new concept using a surface acoustic wave filter as a time interpolator. Construction of the device is briefly described. The experiments described were focused on evaluating the timing precision and stability. Low-jitter test pulses with a repetition frequency of 763 Hz were generated synchronously to the local time base and their times of arrival were measured. The resulting precision of a single measurement was typically 900 fs RMS, and a timing stability TDEV of 4 fs was achieved for time intervals in the range from 300 s to 2 h. To our knowledge this is the best value reported to date for the stability of a timing device. The experimental results are discussed and possible improvements are proposed.

  7. Single channel speech enhancement using MMSE estimation of short-time modulation magnitude spectrum

    E-print Network

    Single channel speech enhancement using MMSE estimation of short-time modulation magnitude spectrum magnitude estimation in the modulation domain. For this purpose, the traditional analysis- modification for additive noise distortion by applying the MMSE short-time spectral magnitude estimation algorithm

  8. Characterizing bioterrorist attacks from a short time series of diagnosed patient data -A Bayesian approach

    E-print Network

    Ray, Jaideep

    Characterizing bioterrorist attacks from a short time series of diagnosed patient data - A Bayesian on a short time-series of diagnosed patients exhibiting symptoms. To be of relevance to response planning, we not always be captured on environmental sensors. Examples in- clude small releases that may not travel far

  9. An Optimal Mitigation Strategy Against the Asteroid Impact Threat with Short Warning Time

    NASA Technical Reports Server (NTRS)

    Wie, Bong; Barbee, Brent; Pitz, Alan; Kaplinger, Brian; Hawkins, Matt; Winkler, Tim; Premaratne, Pavithra; Vardaxis, George; Lyzhoft, Joshua; Zimmerman, Ben

    2015-01-01

    To develop an innovative yet practically implementable mitigation technique for the most probable impact threat of an asteroid or comet with short warning time (i.e., when we don't have sufficient warning times for a deflection mission).

  10. Maximum entropy spectral analysis of climatic time series revisited: Assessing the statistical significance of estimated spectral peaks

    Microsoft Academic Search

    Eulogio Pardo-Igzquiza; Francisco J. Rodrguez-Tovar

    2006-01-01

    One of the most often used methods in the spectral analysis of climatic time series is the parametric method of maximum entropy based on an autoregressive model. The method of maximum entropy is particularly appealing because of its high resolution and its good performance with short time series. Its main drawback is that the statistical significance of the spectral peaks

  11. Deducing acidification rates based on short-term time series.

    PubMed

    Lui, Hon-Kit; Arthur Chen, Chen-Tung

    2015-01-01

    We show that, statistically, the simple linear regression (SLR)-determined rate of temporal change in seawater pH (?pH), the so-called acidification rate, can be expressed as a linear combination of a constant (the estimated rate of temporal change in pH) and SLR-determined rates of temporal changes in other variables (deviation largely due to various sampling distributions), despite complications due to different observation durations and temporal sampling distributions. Observations show that five time series data sets worldwide, with observation times from 9 to 23 years, have yielded ?pH values that vary from 1.61??10(-3) to -2.5??10(-3)?pH unit yr(-1). After correcting for the deviation, these data now all yield an acidification rate similar to what is expected under the air-sea CO2 equilibrium (-1.6??10(-3)?~?-1.8??10(-3)?pH unit yr(-1)). Although long-term time series stations may have evenly distributed datasets, shorter time series may suffer large errors which are correctable by this method. PMID:26143749

  12. Short Time-Scale Emission Line Variations in Mira B

    NASA Astrophysics Data System (ADS)

    Chamber, H. L., II; Moffett, T. J.; Barnes, T. G., III

    1997-05-01

    Spectra of Mira were taken at McDonald Observatory near Mira A minimum in December 1975 using an image tube spectrograph. Series of spectra on a two to three minute time-scale show significant line strength variations in the emission lines associated with Mira B.

  13. A Kalman filtering approach to short-time Fourier analysis

    Microsoft Academic Search

    R. R. Bitmead; Ah Tsoi; P. Parker

    1986-01-01

    The problem of estimating time-varying harmonic components of a signal measured in noise is considered. The approach used is via state estimation. Two methods are proposed, one involving pole-placement of a state observer, the other using quadratic optimization techniques. The result is the development of a new class of filters, akin to recursive frequency-sampling filters, for inclusion in a parallel

  14. Revisiting Bluetooth Security (Short Paper)

    Microsoft Academic Search

    Manik Lal Das; Ravi Mukkamala

    2008-01-01

    Bluetooth technology is gaining increasing interest in the research community because of the convenience of exchanging information\\u000a between wireless devices. As the communication medium is wireless, security is an important concern in this emerging technology.\\u000a This paper discusses the basic security of Bluetooth technology, some of its shortcomings and presents two new proposals for\\u000a securing Bluetooth technology. One of the

  15. A short time step response factor model for vertical ground loop heat exchangers

    SciTech Connect

    Yavuzturk, C.; Spitler, J.D.

    1999-07-01

    The short-term behavior of ground-coupled heat pump systems is important for design of ground loop heat exchangers, energy analysis of ground source heat pump systems, and design of hybrid ground source systems. This paper describes the development of short time-step temperature response factors for vertical ground loop heat exchangers as used in ground-coupled heat pump systems. The short time-step response factors allow for a direct evaluation of system energy consumption and electrical demand in hourly or shorter time intervals. The development of the temperature response factors is based on an analytically validated, transient two-dimensional implicit finite volume model designed for the simulation of heat transfer over a vertical U-tube ground heat exchanger. The short time-step response factors are implemented as part of a component model for TRNSYS and an example application is provided based on an actual building.

  16. Short residence time coal liquefaction process including catalytic hydrogenation

    DOEpatents

    Anderson, R.P.; Schmalzer, D.K.; Wright, C.H.

    1982-05-18

    Normally solid dissolved coal product and a distillate liquid product are produced by continuously passing a feed slurry comprising raw feed coal and a recycle solvent oil and/or slurry together with hydrogen to a preheating-reaction zone, the hydrogen pressure in the preheating-reaction zone being at least 1,500 psig (105 kg/cm[sup 2]), reacting the slurry in the preheating-reaction zone at a temperature in the range of between about 455 and about 500 C to dissolve the coal to form normally liquid coal and normally solid dissolved coal. A total slurry residence time is maintained in the reaction zone ranging from a finite value from about 0 to about 0.2 hour, and reaction effluent is continuously and directly contacted with a quenching fluid to substantially immediately reduce the temperature of the reaction effluent to below 425 C to substantially inhibit polymerization so that the yield of insoluble organic matter comprises less than 9 weight percent of said feed coal on a moisture-free basis. The reaction is performed under conditions of temperature, hydrogen pressure and residence time such that the quantity of distillate liquid boiling within the range C[sub 5]-454 C is an amount at least equal to that obtainable by performing the process under the same condition except for a longer total slurry residence time, e.g., 0.3 hour. Solvent boiling range liquid is separated from the reaction effluent and recycled as process solvent. The amount of solvent boiling range liquid is sufficient to provide at least 80 weight percent of that required to maintain the process in overall solvent balance. 6 figs.

  17. Short residence time coal liquefaction process including catalytic hydrogenation

    DOEpatents

    Anderson, Raymond P. (Overland Park, KS); Schmalzer, David K. (Englewood, CO); Wright, Charles H. (Overland Park, KS)

    1982-05-18

    Normally solid dissolved coal product and a distillate liquid product are produced by continuously passing a feed slurry comprising raw feed coal and a recycle solvent oil and/or slurry together with hydrogen to a preheating-reaction zone (26, alone, or 26 together with 42), the hydrogen pressure in the preheating-reaction zone being at least 1500 psig (105 kg/cm.sup.2), reacting the slurry in the preheating-reaction zone (26, or 26 with 42) at a temperature in the range of between about 455.degree. and about 500.degree. C. to dissolve the coal to form normally liquid coal and normally solid dissolved coal. A total slurry residence time is maintained in the reaction zone ranging from a finite value from about 0 to about 0.2 hour, and reaction effluent is continuously and directly contacted with a quenching fluid (40, 68) to substantially immediately reduce the temperature of the reaction effluent to below 425.degree. C. to substantially inhibit polymerization so that the yield of insoluble organic matter comprises less than 9 weight percent of said feed coal on a moisture-free basis. The reaction is performed under conditions of temperature, hydrogen pressure and residence time such that the quantity of distillate liquid boiling within the range C.sub.5 -454.degree. C. is an amount at least equal to that obtainable by performing the process under the same condition except for a longer total slurry residence time, e.g., 0.3 hour. Solvent boiling range liquid is separated from the reaction effluent (83) and recycled as process solvent (16). The amount of solvent boiling range liquid is sufficient to provide at least 80 weight percent of that required to maintain the process in overall solvent balance.

  18. A weighted overlap-add method of short-time Fourier analysis\\/Synthesis

    Microsoft Academic Search

    R. E. CROCHIERE

    1980-01-01

    In this correspondence we present a new structure and a simplified interpretation of short-time Fourier synthesis using synthesis windows. We show that this approach can be interpreted as a modification of the overlap-add method where we inverse the Fourier transform and window by the synthesis window prior to overlap-adding. This simplified interpretation results in a more efficient structure for short-time

  19. Simulations of mass-transport processes on short observation time scales in nonideal dissipative systems

    Microsoft Academic Search

    O. S. Vaulina; O. F. Petrov; V. E. Fortov

    2005-01-01

    We present the results of our numerical simulations of mass-transport processes on short observation time scales for extended\\u000a quasi-two-dimensional and three-dimensional nonideal dissipative systems of macroparticles interacting through a screened\\u000a Coulomb potential. The simulations were performed for the parameters corresponding to the experimental conditions in laboratory\\u000a dusty plasmas. The evolution of the rms macroparticle displacement on short observation time scales

  20. Short-time forecasting of the system magnetosheath -magnetosphere

    NASA Astrophysics Data System (ADS)

    Dobreva, Polya; Iliev, Hristo; Grigorov, Krum; Koitchev, Detelin; Keremidarska, Valentina; Kartalev, Monio

    We report on the efforts to optimize the performance of a new magnetosphere-magnetosheath model in order to achieve at least 30 minutes forecasting advance of the near-Earth space. The utilized model, developed at the Institute of Mechanics, Bulgarian Academy of Sciences, consists of two models, describing self-consistently the magnetosheath-magnetosphere system. The 3D magnetosheath modul receives the flow distribution at the magnetosheath region (in gasdynamic approach). The magnetosphere model is a modification of the Tsyganenko magnetic field model with numerically calculated shielding field and boundary. The locations and shapes of the bow shock and magnetopause are also described as a part of the solution. The 3D form of the magnetopause (generally non-axially-symmetric), including the cusp indentation, influences essentially the flow. Input data for the whole model are density, temperature, flow velocity and interplanetary magnetic field (IMF). A complementary part of the system is a set of algorithms and programs, making use of the available in Internet near real time solar wind monitoring in L1 (currently performed by ACE). In order to modernize and extend the existing simulation software, several performance optimization techniques were applied to the FORTRAN source code. Also parts of the code are being incrementally parallelized using OpenMP directives. The simulations run on several multicore x86-64 machines under 64-bit Linux OS. The traveling time of the solar wind from L1 to the Earth is enough for running the magnetosheath-magnetosphere problem. Numerical experiments, performed on different configuration of the computer platform are discussed.

  1. Nonmonotonic short-time decay of the Loschmidt echo in quasi-one-dimensional systems.

    PubMed

    Goussev, Arseni

    2011-05-01

    We study the short-time stability of quantum dynamics in quasi-one-dimensional systems with respect to small localized perturbations of the potential. To this end, we analytically and numerically address the decay of the Loschmidt echo (LE) during times that are short compared to the Ehrenfest time. We find that the LE is generally a nonmonotonic function of time and exhibits strongly pronounced minima and maxima at the instants when the corresponding classical particle traverses the perturbation region. We also show that, under general conditions, the envelope decay of the LE is well approximated by a Gaussian, and we derive explicit analytical formulas for the corresponding decay time. Finally, we demonstrate that the observed nonmonotonic nature of the LE decay is only pertinent to one-dimensional (and, more generally, quasi-one-dimensional) systems, and that the short-time decay of the LE can be monotonic in a higher number of dimensions. PMID:21728633

  2. Healthy Work Revisited: Do Changes in Time Strain Predict Well-Being?

    PubMed Central

    Moen, Phyllis; Kelly, Erin L.; Lam, Jack

    2013-01-01

    Building on Karasek and Theorell (R. Karasek & T. Theorell, 1990, Healthy work: Stress, productivity, and the reconstruction of working life, New York, NY: Basic Books), we theorized and tested the relationship between time strain (work-time demands and control) and seven self-reported health outcomes. We drew on survey data from 550 employees fielded before and 6 months after the implementation of an organizational intervention, the Results Only Work Environment (ROWE) in a white-collar organization. Cross-sectional (Wave 1) models showed psychological time demands and time control measures were related to health outcomes in expected directions. The ROWE intervention did not predict changes in psychological time demands by Wave 2, but did predict increased time control (a sense of time adequacy and schedule control). Statistical models revealed increases in psychological time demands and time adequacy predicted changes in positive (energy, mastery, psychological well-being, self-assessed health) and negative (emotional exhaustion, somatic symptoms, psychological distress) outcomes in expected directions, net of job and home demands and covariates. This study demonstrates the value of including time strain in investigations of the health effects of job conditions. Results encourage longitudinal models of change in psychological time demands as well as time control, along with the development and testing of interventions aimed at reducing time strain in different populations of workers. PMID:23506547

  3. Scheduling to Minimize Average Completion Time Revisited: Deterministic On-line Algorithms

    E-print Network

    Megow, Nicole

    2004-02-06

    We consider the scheduling problem of minimizing the average weighted completion time on identical parallel machines when jobs are arriving over time. For both the preemptive and the nonpreemptive setting, we show that ...

  4. Revisiting the Development of Time Sharing Using a Dual Motor Task Performance

    ERIC Educational Resources Information Center

    Getchell, Nancy; Pabreja, Priya

    2006-01-01

    In this article, the authors discuss and examine how to develop time sharing using a dual motor task and its effects. They state that when one is required to perform two tasks at the same time (time sharing), an individual may experience difficulty in expressing one or both of the tasks. This phenomenon, known as interference, has been studied

  5. Method to modify random matrix theory using short-time behavior in chaotic systems.

    PubMed

    Smith, A Matthew; Kaplan, Lev

    2009-09-01

    We discuss a modification to random matrix theory (RMT) eigenstate statistics that systematically takes into account the nonuniversal short-time behavior of chaotic systems. The method avoids diagonalization of the Hamiltonian, instead requiring only knowledge of short-time dynamics for a chaotic system or ensemble of similar systems. Standard RMT and semiclassical predictions are recovered in the limits of zero Ehrenfest time and infinite Heisenberg time, respectively. As examples, we discuss wave-function autocorrelations and cross correlations and show how the approach leads to a significant improvement in the accuracy for simple chaotic systems where comparison can be made with brute-force diagonalization. PMID:19905169

  6. Revisiting the Time Trade-Off Hypothesis: Work, Organized Activities, and Academics During College.

    PubMed

    Greene, Kaylin M; Maggs, Jennifer L

    2015-08-01

    How adolescents spend their time has long-term implications for their educational, health, and labor market outcomes, yet surprisingly little research has explored the time use of students across days and semesters. The current study used longitudinal daily diary data from a sample of college students attending a large public university in the Northeastern US (n=726, M age=18.4) that was followed for 14days within each of seven semesters (for up to 98 diary days per student). The study had two primary aims. The first aim was to explore demographic correlates of employment time, organized activity time, and academic time. The second aim was to provide a rigorous test of the time trade-off hypothesis, which suggests that students will spend less time on academics when they spend more time on employment and extracurricular activities. The results demonstrated that time use varied by gender, parental education, and race/ethnicity. Furthermore, the results from multi-level models provided some support for the time trade-off hypothesis, although associations varied by the activity type and whether the day was a weekend. More time spent on employment was linked to less time spent on academics across days and semesters whereas organized activities were associated with less time on academics at the daily level only. The negative associations between employment and academics were most pronounced on weekdays. These results suggest that students may balance certain activities across days, whereas other activities may be in competition over longer time frames (i.e., semesters). PMID:25381597

  7. Integrating Random Matrix Theory Predictions with Short-Time Dynamical Effects in Chaotic Systems

    E-print Network

    A. Matthew Smith; Lev Kaplan

    2010-06-29

    We discuss a modification to Random Matrix Theory eigenstate statistics, that systematically takes into account the non-universal short-time behavior of chaotic systems. The method avoids diagonalization of the Hamiltonian, instead requiring only a knowledge of short-time dynamics for a chaotic system or ensemble of similar systems. Standard Random Matrix Theory and semiclassical predictions are recovered in the limits of zero Ehrenfest time and infinite Heisenberg time, respectively. As examples, we discuss wave function autocorrelations and cross-correlations, and show that significant improvement in accuracy is obtained for simple chaotic systems where comparison can be made with brute-force diagonalization. The accuracy of the method persists even when the short-time dynamics of the system or ensemble is known only in a classical approximation. Further improvement in the rate of convergence is obtained when the method is combined with the correlation function bootstrapping approach introduced previously.

  8. Nutrient timing revisited: is there a post-exercise anabolic window?

    PubMed Central

    2013-01-01

    Nutrient timing is a popular nutritional strategy that involves the consumption of combinations of nutrients--primarily protein and carbohydrate--in and around an exercise session. Some have claimed that this approach can produce dramatic improvements in body composition. It has even been postulated that the timing of nutritional consumption may be more important than the absolute daily intake of nutrients. The post-exercise period is widely considered the most critical part of nutrient timing. Theoretically, consuming the proper ratio of nutrients during this time not only initiates the rebuilding of damaged muscle tissue and restoration of energy reserves, but it does so in a supercompensated fashion that enhances both body composition and exercise performance. Several researchers have made reference to an anabolic window of opportunity whereby a limited time exists after training to optimize training-related muscular adaptations. However, the importance - and even the existence - of a post-exercise window can vary according to a number of factors. Not only is nutrient timing research open to question in terms of applicability, but recent evidence has directly challenged the classical view of the relevance of post-exercise nutritional intake with respect to anabolism. Therefore, the purpose of this paper will be twofold: 1) to review the existing literature on the effects of nutrient timing with respect to post-exercise muscular adaptations, and; 2) to draw relevant conclusions that allow practical, evidence-based nutritional recommendations to be made for maximizing the anabolic response to exercise. PMID:23360586

  9. The Aharonov-Bohm Effect Revisited by an Acoustic Time-Reversal Mirror

    Microsoft Academic Search

    Philippe Roux; Julien de Rosny; Mickael Tanter; Mathias Fink

    1997-01-01

    We take advantage of the violation of time-reversal invariance for acoustic waves to achieve a new way of characterizing a vorticity field with a double time-reversal mirror (TRM). In particular, we show experimentally that the double TRM works as a vorticity amplifier. In the case of a vorticity filament, the sound-vorticity interaction is interpreted as the acoustical analog of the

  10. Short Term Chaotic Time Series Prediction using Symmetric LS-SVM Regression

    E-print Network

    Short Term Chaotic Time Series Prediction using Symmetric LS-SVM Regression Marcelo Espinoza, Johan predictions for chaotic time series are generated using Least-Squares Support Vector Ma- chines (LS-SVM) regression. We show that LS-SVM with symmetry constraints can produce accurate pre- dictions. Not only

  11. Short time Fourier analysis of the electromyogram - Fast movements and constant contraction

    NASA Technical Reports Server (NTRS)

    Hannaford, Blake; Lehman, Steven

    1986-01-01

    Short-time Fourier analysis was applied to surface electromyograms (EMG) recorded during rapid movements, and during isometric contractions at constant forces. A portion of the data to be transformed by multiplying the signal by a Hamming window was selected, and then the discrete Fourier transform was computed. Shifting the window along the data record, a new spectrum was computed each 10 ms. The transformed data were displayed in spectograms or 'voiceprints'. This short-time technique made it possible to see time-dependencies in the EMG that are normally averaged in the Fourier analysis of these signals. Spectra of EMGs during isometric contractions at constant force vary in the short (10-20 ms) term. Short-time spectra from EMGs recorded during rapid movements were much less variable. The windowing technique picked out the typical 'three-burst pattern' in EMG's from both wrist and head movements. Spectra during the bursts were more consistent than those during isometric contractions. Furthermore, there was a consistent shift in spectral statistics in the course of the three bursts. Both the center frequency and the variance of the spectral energy distribution grew from the first burst to the second burst in the same muscle. The analogy between EMGs and speech signals is extended to argue for future applicability of short-time spectral analysis of EMG.

  12. Direct Visualization of Short Transverse Relaxation Time Component (ViSTa)

    PubMed Central

    Oh, Se-Hong; Bilello, Michel; Schindler, Matthew; Markowitz, Clyde E.; Detre, John A.; Lee, Jongho

    2013-01-01

    White matter of the brain has been demonstrated to have multiple relaxation components. Among them, the short transverse relaxation time component (T2 < 40 ms; T2* < 25 ms at 3T) has been suggested to originate from myelin water whereas long transverse relaxation time components have been associated with axonal and/or interstitial water. In myelin water imaging, T2 or T2* signal decay is measured to estimate myelin water fraction based on T2 or T2* differences among the water components. This method has been demonstrated to be sensitive to demyelination in the brain but suffers from low SNR and image artifacts originating from ill-conditioned multi-exponential fitting. In this study, a novel approach that selectively acquires short transverse relaxation time signal is proposed. The method utilizes a double inversion RF pair to suppress a range of long T1 signal. This suppression leaves short T2* signal, which has been suggested to have short T1, as the primary source of the image. The experimental results confirms that after suppression of long T1 signals, the image is dominated by short T2* in the range of myelin water, allowing us to directly visualize the short transverse relaxation time component in the brain. Compared to conventional myelin water imaging, this new method of direct visualization of short relaxation time component (ViSTa) provides high quality images. When applied to multiple sclerosis patients, chronic lesions show significantly reduced signal intensity in ViSTa images suggesting sensitivity to demyelination. PMID:23796545

  13. Cluster tools with chamber revisiting-modeling and analysis using timed Petri nets

    Microsoft Academic Search

    Wlodek M. Zuberek

    2004-01-01

    Timed Petri nets are formal models of discrete concurrent systems. Since the durations of all activities are included in the model descriptions, many performance characteristics can be derived from such models. In the case of cluster tools, net models represent the flow of wafers through the chambers of the tool as well as consecutive actions performed by the robotic transporter.

  14. Lakatos Revisited.

    ERIC Educational Resources Information Center

    Court, Deborah

    1999-01-01

    Revisits and reviews Imre Lakatos' ideas on "Falsification and the Methodology of Scientific Research Programmes." Suggests that Lakatos' framework offers an insightful way of looking at the relationship between theory and research that is relevant not only for evaluating research programs in theoretical physics, but in the social sciences as

  15. Analysis of fMRI Time-Series RevisitedAgain

    Microsoft Academic Search

    K. J. Worsley; K. J. Friston

    1995-01-01

    Friston et al. (1995, NeuroImage 2:45-53) presented a method for detecting activations in fMR1 time-series based on the general linear model and a heuristic analysis of the effective degrees of freedom. In this communication we present corrected results that replace those of the previous paper and solve the same problem without recourse to heuristic arguments. Specifically we introduce a proper

  16. Performance analysis of FlexRay-based systems using real-time calculus, revisited

    Microsoft Academic Search

    Devesh B. Chokshi; Purandar Bhaduri

    2010-01-01

    The FlexRay protocol (4) is likely to be the de facto standard for automotive communication systems. Hence, there is a need to provide hard performance guarantees on properties like worst case response times of messages, their buer re- quirements, end-to-end latency (for example, from sensor to actuator), etc., for FlexRay based systems. The paper (11) provides an analysis for finding

  17. Hate networks revisited: time and user interface dependence study of user emotions in political forum

    E-print Network

    Sobkowicz, Pawel

    2011-01-01

    The paper presents analysis of time evolution within am Internet political forum, characterized by large political differences and high levels of emotions. The study compares samples of discussions gathered at three periods separated by important events. We focus on statistical aspects related to emotional content of communication and changes brought by technologies that increase or decrease the direct one-to-one discussions. We discuss implications of user interface aspects on promoting communication across a political divide.

  18. Timescale modification of speech based on short-time Fourier analysis

    Microsoft Academic Search

    M. Portnoff

    1981-01-01

    This paper develops the theoretical basis for time-scale modification of speech based on short-time Fourier analysis. The goal is the development of a high-quality system for changing the apparent rate of articulation of recorded speech, while at the same time preserving such qualities as naturalness, intelligibility, and speaker-dependent features. The results of the theoretical study were used as the framework

  19. On the short-term predictability of exchange rates: A BVAR time-varying parameters approach

    Microsoft Academic Search

    Nicholas Sarantis

    2006-01-01

    In this paper we propose a Bayesian vector autoregressive model with time-varying parameters (BVAR-TVP) to examine the short-term predictability of exchange rates. An important contribution of the paper is the application of the BVAR-TVP model, for the first time, to daily data using information from financial markets. Another contribution is the production of forecasts in real time at the very

  20. Revisiting the Stark Broadening by fluctuating electric fields using the Continuous Time Random Walk Theory

    NASA Astrophysics Data System (ADS)

    Capes, H.; Christova, M.; Boland, D.; Catoire, F.; Godbert-Mouret, L.; Koubiti, M.; Mekkaoui, A.; Rosato, J.; Marandet, Y.; Stamm, R.

    2010-10-01

    Stark broadening of atomic lines in plasmas is calculated by modelling the plasma stochastic electric field using the CTRW approach [1,2]. This allows retaining non Markovian terms in the Schrdinger equation averaged over the electric field fluctuations. As an application we consider a special case of a non separable CTRW process, the so called Kangaroo process [3]. An analytic expression for the line profile is presented for arbitrary waiting time distribution functions. A preliminary application to the hydrogen Lyman ? line is discussed.

  1. Revisiting the measurement of the spin relaxation time in graphene-based spintronic devices

    NASA Astrophysics Data System (ADS)

    Idzuchi, Hiroshi; Fert, Albert; Otani, Yoshichika

    2015-03-01

    Spin transport in graphene has strongly drawn attention because of the expected long spin relaxation time ?sf, but, ?sf derived from experiments is rarely above 1 ns, shorter than theoretically expected and also largely dispersed. Here we reanalyze Hanle curves in graphene-based lateral spin valves with various contacts by using the recently established model of Hanle effect taking into account the spin absorption by contacts. We found the reanalysis of Hanle curves of four samples from transparent contacts to tunnel contacts, reported in ref.3, gives longer and much less dispersed ?sf ranging around 500 ps compared to the original values ranging from 84 ps to 495 ps. Extending our analysis to typical recent experiments with long spin diffusion length, ? ~ 10 ?m, we find the spin absorption is even more pronounced because the contact resistance R needed to suppress the spin absorption scales with the spin resistance ~ ? . Thus R in the range of 100 kOhm is generally not large enough to suppress the spin absorption, and taking into account the contacts is more important to characterize the real ?sf in graphene with ? in this range.

  2. Revisiting discharge increments: variability in space and time of water delivery to the stream

    NASA Astrophysics Data System (ADS)

    Szeftel, P.; Moore, R. D.; Weiler, M.

    2009-12-01

    The spatial and temporal variability of water delivery mechanisms to the stream network was examined in the Cotton Creek Experimental Watershed (CCEW), a 17 km2 snow-dominated watershed located in south-eastern British Columbia, Canada. Our objectives were 1) to determine the first order controls on water delivery mechanisms from the scale of the slope to that of the whole watershed and 2) to highlight the shift in nature of these controls as the flow regime evolves from freshet to low flow. Following a scale connecting approach, we conceptualized the watershed as an aggregation of incremental contributing areas (ICAs), each representing the incremental addition of drainage area along a stream reach. Cotton Creeks stream network was divided into 23 reaches, with ICAs ranging from 0.05 to 2.7km2 in size. Stream discharge was measured at both ends of each reach in order to compute flow increments, the net water budget over the length of the reach. Streamflow gauging campaigns were repeated from freshet to baseflow periods for years 2005-2008. Preliminary investigations showed that lateral contributions from ICA were highly variable both in space and time. Through a Principal Component Analysis, this variability was related to the annual forcing (snowmelt) and the individual recession characteristics of ICAs. During the wet state of the catchment, ICA contributions were moderately explained with contributing area. Topographic controls, especially contour curvature controlled ICA contributions during intermediate wetness states. Controls on water delivery during low flows were difficult to identify, probably due to a great uncertainty characterizing discharge measurements and resulting discharge increments. This approach permits the observation of emergent behaviors between the ICA and watershed scales. It also offers a temporally dynamic definition of first order controls on water delivery to the stream network, which can help refine hydrological models.

  3. How Do Young Children's Spatio-Symbolic Skills Change over Short Time scales?

    ERIC Educational Resources Information Center

    Tsubota, Yoko; Chen, Zhe

    2012-01-01

    Three experiments were designed to examine how experience affects young children's spatio-symbolic skills over short time scales. Spatio-symbolic reasoning refers to the ability to interpret and use spatial relations, such as those encountered on a map, to solve symbolic tasks. We designed three tasks in which the featural and spatial

  4. Speech enhancement using a minimum-mean square error short-time spectral amplitude estimator

    Microsoft Academic Search

    Y. Ephraim; D. Malah

    1984-01-01

    This paper focuses on the class of speech enhancement systems which capitalize on the major importance of the short-time spectral amplitude (STSA) of the speech signal in its perception. A system which utilizes a minimum mean-square error (MMSE) STSA estimator is proposed and then compared with other widely used systems which are based on Wiener filtering and the \\

  5. Iterative reconstruction of speech from short-time Fourier transform phase and magnitude spectra

    E-print Network

    Iterative reconstruction of speech from short-time Fourier transform phase and magnitude spectra dimensional, signal reconstruction (specifically speech signals) from the magnitude spectrum and the phase magnitude spectrum, and (iii) a signal can be reconstructed to within a scale factor from its magnitude

  6. A new method for summation of short time CAFs based on RLCS motion

    Microsoft Academic Search

    Seyed Nima Sadrieh; Reza Saadat; Arash Mohammadi

    2008-01-01

    Cross ambiguity function is a common method for joint estimation of TDOA\\/FDOA. CAF performance degrades in wideband situation. The maximum likelihood estimator in wideband model contains data resampling. Because of intensive computational burden data resampling isnpsilat viewed as a practical method. Calculation of short time CAFs and summation of them is suggested as a practical alternative method. Different summation methods

  7. PHYSICAL REVIEW E 84, 031932 (2011) Short-time evolution in the adaptive immune system

    E-print Network

    Dinner, Aaron

    2011-01-01

    PHYSICAL REVIEW E 84, 031932 (2011) Short-time evolution in the adaptive immune system Nicholas as a whole is considered to have failed. This situation is seen in the adaptive immune system. During and it can then be amplified after reduction of the mutation factor (as in the immune system

  8. New methods for regulating flowering time in short-day strawberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Higher percentages of transplants of short-day cultivars 'Chandler', 'Carmine', 'Strawberry Festival', and 'Sweet Charlie' from runner tips plugged in early July rather than the standard time (early August) bloomed in the fall. Nearly 100% of the transplants produced in early July flowered in the f...

  9. Conversion of hydrocarbon fuels to syngas in a short contact time catalytic reactor

    Microsoft Academic Search

    L. Bobrova; N. Vernikovskaya; V. Sadykov

    2009-01-01

    Some results of the theoretical and experimental research on the oxidative production of syngas from hydrocarbon fuels in catalytic reactors which operate at high temperatures and short contact times are presented. Pilot scale tests of the partial oxidation of methane, isooctane and gasoline have been carried out in nearly adiabatic conditions on structured catalysts developed at the Boreskov Institute of

  10. Short communication Real-time estimation of lead-acid battery parameters: A dynamic

    E-print Network

    Ray, Asok

    packs are increasingly being used in vehicles, renewable energy applications, power backup systems) to efficiently allocate power and energy within battery packs and between other prime movers such as internalShort communication Real-time estimation of lead-acid battery parameters: A dynamic data

  11. Speech enhancement using a minimum mean-square error short-time spectral modulation magnitude estimator

    E-print Network

    . Keywords: Modulation domain; Analysis-modification-synthesis (AMS); Speech enhancement; MMSE short-time in the modu- lation domain. For this purpose, the traditional analysis-modification-synthesis framework with speech presence uncertainty) with that enhanced using different acoustic domain MMSE magnitude estimator

  12. Reconstruction of a wind turbine's endured load spectrum using a short-time load measurement

    E-print Network

    Berlin,Technische Universitt

    Reconstruction of a wind turbine's endured load spectrum using a short-time load measurement-related individually renewed calculation as methods. However, the endured loads of an individual WT can only be realistically estimated based on direct load measurements. Therefore, the method described here proposes

  13. Text and Language Independent Speaker Identification By Using Short-Time Low Quality Signals

    E-print Network

    Virrankoski, Reino

    identification applications that exploit voice signals recorded by using wireless networks of small, lowText and Language Independent Speaker Identification By Using Short-Time Low Quality Signals and language independent speaker identification algorithm based on a cepstral speech parameterization method

  14. Optimal filtering of dynamics in short-time features for music organization

    Microsoft Academic Search

    Jernimo Arenas-garca; Jan Larsen; Lars Kai Hansen; Anders Meng

    2006-01-01

    There is an increasing interest in customizable methods for organizing music collections. Relevant music characteriza- tion can be obtained from short-time features, but it is not obvious how to combine them to get useful information. In this work, a novel method, denoted as the Positive Con- strained Orthonormalized Partial Least Squares (POPLS), is proposed. Working on the periodograms of MFCCs

  15. Analysis of array errors and a short-time processor in airborne phased array radars

    Microsoft Academic Search

    Qing-Guang Liu; Ying-Ning Peng

    1996-01-01

    Array errors are inherent in a realistic phased array radar system. The influence of array errors on the clutter degrees of freedom and the clutter subspace in an airborne phased array radar is analyzed. Based on the presented theoretic results, a method of short-time processing followed by coherent integration is proposed for clutter suppression in airborne phased array radars. It

  16. The short- and long-time diffusivities of many spheres in the presence of depletants

    NASA Astrophysics Data System (ADS)

    Karzar-Jeddi, Mehdi; Tuinier, Remco; Taniguchi, Takashi; Fan, Tai-Hsi

    2014-03-01

    In a colloid-polymer mixture, polymer depletion plays a key role in phase behaviors and transport properties of colloids. We investigate the stochastic motion of many colloidal spheres in dilute polymer solutions and resolve the short-time and long-time self-diffusivities of the spheres under the depletion effect. The pair additive mobility tensor is computed by the boundary integral method, which accounts for the solvent or depletion layer, and a uniform bulk polymer solution elsewhere. The stochastic Brownian displacement is coupled to the mobility analysis through the fluctuation-dissipation theorem. By tracking the particle trajectories, we found a significant increase of the short-time self-diffusivity due to caged depletion effects. Additional to the slip-like behavior that enhances the diffusivity, the long-time behavior is further complicated by the entropic force that tends to coagulate the spheres.

  17. High-voltage and short-rise-time pulse-transformer with amorphous cores

    Microsoft Academic Search

    N. Kobayashi; N. Aoki; H. Horie; Y. Baba; Y. Sano; H. Kimura; C. Konagal

    1997-01-01

    A short rise time pulsed power transformer using cobalt-based amorphous alloy cores, which operates at high voltage (~100 kV) and high repetition rate (~4000 pps), has been developed for application as a pulsed power modulator for copper vapor lasers. An output voltage of more than 80 kV, a rise time of 65 ns and a transformation efficiency of 83% were

  18. Representation and Identification of Nonlinear Systems in the Short-Time Fourier Transform Domain

    Microsoft Academic Search

    Yekutiel Avargel; Israel Cohen

    In this chapter, we introduce a novel approach for improved nonlinear system identification in the short-time Fourier transform\\u000a (STFT) domain. We first derive explicit representations of discrete-time Volterra filters in the STFT domain. Based on these\\u000a representations, approximate nonlinear STFT models, which consist of parallel combinations of linear and nonlinear components,\\u000a are developed. The linear components are represented by crossband

  19. High temperature short time air puffed ready-to-eat (RTE) potato snacks: Process parameter optimization

    Microsoft Academic Search

    A. Nath; P. K. Chattopadhyay; G. C. Majumdar

    2007-01-01

    Ready-to-eat (RTE) potato snacks were developed with high temperature short time (HTST) air puffing process based on centre composite RSM design. The effects of process parameters viz. puffing temperature (175275C), puffing time (1575s), initial moisture content (3040%) and air velocity (2.44.8m\\/s) on quality attributes such as expansion ratio, hardness, ascorbic acid loss and overall acceptability of the products were investigated.

  20. Efficient Iterative Time-Domain Beam Propagation Methods for Ultra Short Pulse Propagation: Analysis and Assessment

    Microsoft Academic Search

    Husain M. Masoudi; Mohammad S. Akond

    2011-01-01

    The time-domain beam propagation method (TD-BPM) has been implemented and analyzed using several iterative numerical techniques to model the propagation of ultra short pulses in optical structures. The methods depend on one-way non-paraxial time domain propagation that use Pade approximant formulation. Several numerical tests showed that the iterative TD-BPM techniques are very stable and converge using few iterations. From accuracy

  1. Short-time fourier transform based analysis to characterization of series arc fault

    Microsoft Academic Search

    Cheng Hong; Chen Xiaojuan; Xiao Wei; Wang Cong

    2009-01-01

    Considering the non-periodic and non-stationary signatures of series arc fault current signals, a time-frequency analyzing method for series arc faults detection is presented based on short-time Fourier transform. The algorithm of STFT using the Hanning window function is described in detail, in which the length of the window function and the sliding step parameters are discussed to obtain 20 ms

  2. Time-lapse Camera System for Monitoring Short and Long-term Sedimentary Processes

    Microsoft Academic Search

    Nicholas I Scappaticci; Brian E Bodenbender

    2011-01-01

    Time-lapse photography has seen limited use as a method for observing sedimentary processes. A problem with past techniques is the use of expensive components, limiting availability for most applications. The purpose of this project is to develop a low-cost, modular time-lapse system for both short- and long-term deployment in the field to photographically monitor various sedimentary processes, such as erosion

  3. Vigintiphobia revisited.

    PubMed

    Watchko, Jon F

    2005-06-01

    In this review the historical tenets and evidence-based clinical research in support of a bilirubin exchange threshold of >20 mg/dL for the healthy term neonate are revisited. In addition, a hypothesis is ventured that recent cases of kernicterus are related in part to changes in population factors coupled with genetic predispositions that have unmasked an unappreciated potential for marked neonatal hyperbilirubinemia. PMID:15930239

  4. Revisiting Lasswell

    Microsoft Academic Search

    James Farr; Jacob S. Hacker; Nicole Kazee

    2008-01-01

    This article continues the line of argument and historical interpretation we offered in The Policy Scientist of Democracy:\\u000a The Discipline of Harold D. Lasswell by way of a response to Ronald Brunners The Policy Scientist of Democracy Revisited.\\u000a Problems regarding Lasswells capacious vision of the policy scientist and vagaries surrounding democracy, do not diminish\\u000a the importance of the questions Lasswell

  5. Adaptive Filters Revisited :Adaptive Filters Revisited : RFI Mitigation in PulsarRFI Mitigation in Pulsar

    E-print Network

    Ellingson, Steven W.

    Adaptive Filters Revisited :Adaptive Filters Revisited : RFI Mitigation in PulsarRFI Mitigation the IF compatible with the downstream processing. We know the location of the RFI a good reference copy is available. The RFI is strong. Can be implemented in real-time (on-line) hardware. The post

  6. Hierarchical structure of the energy landscape of proteins revisited by time series analysis. II. Investigation of explicit solvent effects

    NASA Astrophysics Data System (ADS)

    Alakent, Burak; Camurdan, Mehmet C.; Doruker, Pemra

    2005-10-01

    Time series analysis tools are employed on the principal modes obtained from the C? trajectories from two independent molecular-dynamics simulations of ?-amylase inhibitor (tendamistat). Fluctuations inside an energy minimum (intraminimum motions), transitions between minima (interminimum motions), and relaxations in different hierarchical energy levels are investigated and compared with those encountered in vacuum by using different sampling window sizes and intervals. The low-frequency low-indexed mode relationship, established in vacuum, is also encountered in water, which shows the reliability of the important dynamics information offered by principal components analysis in water. It has been shown that examining a short data collection period (100ps) may result in a high population of overdamped modes, while some of the low-frequency oscillations (<10cm-1) can be captured in water by using a longer data collection period (1200ps). Simultaneous analysis of short and long sampling window sizes gives the following picture of the effect of water on protein dynamics. Water makes the protein lose its memory: future conformations are less dependent on previous conformations due to the lowering of energy barriers in hierarchical levels of the energy landscape. In short-time dynamics (<10ps), damping factors extracted from time series model parameters are lowered. For tendamistat, the friction coefficient in the Langevin equation is found to be around 40-60cm-1 for the low-indexed modes, compatible with literature. The fact that water has increased the friction and that on the other hand has lubrication effect at first sight contradicts. However, this comes about because water enhances the transitions between minima and forces the protein to reduce its already inherent inability to maintain oscillations observed in vacuum. Some of the frequencies lower than 10cm-1 are found to be overdamped, while those higher than 20cm-1 are slightly increased. As for the long-time dynamics in water, it is found that random-walk motion is maintained for approximately 200ps (about five times of that in vacuum) in the low-indexed modes, showing the lowering of energy barriers between the higher-level minima.

  7. Long-time signatures of short-time dynamics in decaying quantum-chaotic systems

    E-print Network

    T. Gorin; D. F. Martinez; H. Schomerus

    2006-06-27

    We analyze the decay of classically chaotic quantum systems in the presence of fast ballistic escape routes on the Ehrenfest time scale. For a continuous excitation process, the form factor of the decay cross section deviates from the universal random-matrix result on the Heisenberg time scale, i.e. for times much larger than the time for ballistic escape. We derive an exact analytical description and compare our results with numerical simulations for a dynamical model.

  8. Short-duration low-gravity experiments - Time scales, challenges and results

    NASA Technical Reports Server (NTRS)

    Rosenberger, F.

    1993-01-01

    Short-duration low-gravity experiments can be conducted either in drop tubes and drop towers, or on sounding rockets and aircraft on ballistic trajectories. While these facilities offer more frequent flight opportunities and higher cost effectiveness than orbiting spacecraft, their relatively short low-gravity times are often perceived as limiting their utility to only a narrow range of applications and research areas. In this review it is shown, based on scaling laws for diffusive transport of momentum, species and heat, radiative heat transfer and capillarity-driven motion, that with proper consideration of the characteristic length scales, a host of phenomena can be meaningfully investigated during a few seconds. This usefulness of short-duration low-gravity facilities is illustrated with numerous results of recent studies of solidification, combustion, transport in multiphase systems, statics and dynamics of liquid surfaces, magnetic Benard convection, fluid management, transport properties and the graviperception in cells.

  9. A minimal model for short-time diffusion in periodic potentials

    E-print Network

    Clive Emary; Robert Gernert; Sabine H. L. Klapp

    2012-09-07

    We investigate the dynamics of a single, overdamped colloidal particle, which is driven by a constant force through a one-dimensional periodic potential. We focus on systems with large barrier heights where the lowest-order cumulants of the density field, that is, average position and the mean-squared displacement, show nontrivial (non-diffusive) short-time behavior characterized by the appearance of plateaus. We demonstrate that this "cage-like" dynamics can be well described by a discretized master equation model involving two states (related to two positions) within each potential valley. Non-trivial predictions of our approach include analytic expressions for the plateau heights and an estimate of the "de-caging time" obtained from the study of deviations from Gaussian behaviour. The simplicity of our approach means that it offers a minimal model to describe the short-time behavior of systems with hindered dynamics.

  10. Noise of short-time integrators for readout of uncooled infrared bolometer arrays

    NASA Astrophysics Data System (ADS)

    Wrfel, D.; Weiler, D.; Hosticka, B. J.; Vogt, H.

    2010-10-01

    As state-of-the-art readout circuits short-time integrators in Far Infrared (FIR) uncooled bolometer arrays are commonly used. This paper compares the transfer functions of an ideal continuous-time integrator with that of a real integrator with focus an OTA parameters and noise analysis. Beside the noise sources at the non-inverting input of the OTA special care has to be taken to account for capacitances at the inverting input. The Noise Equivalent Temperature Difference (NETD) as the key parameter for bolometer applications for a real short-time integrator will be derived. As the result it will be shown, that the NETD is 1/f-noise limited.

  11. 25 CFR 26.30 - Does the Job Training Program provide part-time training or short-term training?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Does the Job Training Program provide part-time training or short-term training? Yes, part-time and short-term training are allowable...depending upon availability of resources. Part-time means no less than six credit units per...

  12. SLIM--An Early Work Revisited

    SciTech Connect

    Chao, Alex; /SLAC

    2008-07-25

    An early, but at the time illuminating, piece of work on how to deal with a general, linearly coupled accelerator lattice is revisited. This work is based on the SLIM formalism developed in 1979-1981.

  13. Reframing in dentistry: revisited.

    PubMed

    Nuvvula, Sivakumar; Kamatham, Rekalakshmi; Challa, Ramasubbareddy; Asokan, Sharath

    2013-01-01

    The successful practice of dentistry involves a good combination of technical skills and soft skills. Soft skills or communication skills are not taught extensively in dental schools and it can be challenging to learn and at times in treating dental patients. Guiding the child's behavior in the dental operatory is one of the preliminary steps to be taken by the pediatric dentist and one who can successfully modify the behavior can definitely pave the way for a life time comprehensive oral care. This article is an attempt to revisit a simple behavior guidance technique, reframing and explain the possible psychological perspectives behind it for better use in the clinical practice. PMID:24021326

  14. Short Lag Times for Invasive Tropical Plants: Evidence from Experimental Plantings in Hawai'i

    PubMed Central

    Daehler, Curtis C.

    2009-01-01

    Background The lag time of an invasion is the delay between arrival of an introduced species and its successful spread in a new area. To date, most estimates of lag times for plants have been indirect or anecdotal, and these estimates suggest that plant invasions are often characterized by lag times of 50 years or more. No general estimates are available of lag times for tropical plant invasions. Historical plantings and documentation were used to directly estimate lag times for tropical plant invasions in Hawai'i. Methodology/Principal Findings Historical planting records for the Lyon Arboretum dating back to 1920 were examined to identify plants that have since become invasive pests in the Hawaiian Islands. Annual reports describing escape from plantings were then used to determine the lag times between initial plantings and earliest recorded spread of the successful invaders. Among 23 species that eventually became invasive pests, the average lag time between introduction and first evidence of spread was 14 years for woody plants and 5 years for herbaceous plants. Conclusions/Significance These direct estimates of lag times are as much as an order of magnitude shorter than previous, indirect estimates, which were mainly based on temperate plants. Tropical invaders may have much shorter lag times than temperate species. A lack of direct and deliberate observations may have also inflated many previous lag time estimates. Although there have been documented cases of long lag times due to delayed arrival of a mutualist or environmental changes over time, this study suggests that most successful invasions are likely to begin shortly after arrival of the plant in a suitable habitat, at least in tropical environments. Short lag times suggest that controlled field trials may be a practical element of risk assessment for plant introductions. PMID:19223966

  15. Characterization of polydopamine thin films deposited at short times by autoxidation of dopamine.

    PubMed

    Zangmeister, Rebecca A; Morris, Todd A; Tarlov, Michael J

    2013-07-01

    Current interest in melanin films derived from the autoxidation of dopamine stems from their use as a universal adhesion layer. Here we report chemical and physical characterization of polydopamine films deposited on gold surfaces from stirred basic solutions at times ranging from 2 to 60 min, with a focus on times ?10 min. Data from Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and electrochemical methods suggest the presence of starting (dopamine) and intermediate (C=N-containing tautomers of quinone and indole) species in the polydopamine films at all deposition times. A uniform overlayer analysis of the XPS data indicates that film thickness increased linearly at short deposition times of ?10 min. At deposition times ?10 min, the films appeared largely continuous with surface roughness ? ? 2 nm, as determined by atomic force microscopy (AFM). Pinhole-free films, as determined by anionic redox probe measurements, required deposition times of 60 min or greater. PMID:23750451

  16. Semiclassical tunneling splittings from short time dynamics: Herman-Kluk-propagation and harmonic inversion

    NASA Astrophysics Data System (ADS)

    Giese, Kai; Khn, Oliver

    2004-03-01

    We investigate a recently proposed method [J. Chem. Phys. 108, 9206 (1998)] to obtain tunneling splittings from short time cross-correlation matrices that were propagated according to the semiclassical propagator of Herman and Kluk. The energy levels were extracted by harmonic inversion of the cross-correlation matrix using the filter diagonalization technique. The aim of this study is twofold: First, the short time behavior of the Herman-Kluk-propagator and the meaning of using cross-correlation matrices rather than autocorrelation functions is addressed. Numerical examples are given for one- and two-dimensional model potentials. Second, the performance of the method is investigated for a system with considerable anharmonicity and coupling. Here the proton transfer in 3,7-dichlorotropolone is considered using an ab initio reaction surface Hamiltonian approach. For this example also the extension to more dimensions is critically discussed.

  17. Short contact time direct coal liquefaction using a novel batch reactor. Quarterly report, 1996

    SciTech Connect

    Klein, M.T.; Calkins, W.H.; Huang, H.

    1996-05-01

    The objective of this research is to optimize the design and operation of the bench scale batch reactor (SCTBR) for coal liquefaction at short contact times (0.01 to 10 minutes or longer). Additional objectives are to study the kinetics of direct coal liquefaction particularly at short reaction times, and to investigate the role of the organic oxygen components of coal and their reaction pathways during liquefaction. Many of those objectives have already been achieved and others are still in progress. This quarterly report covers further progress toward those objectives. Much of the previous quarterly report was concerned mainly in the retrograde reactions occurring during the liquefaction process. This report is largely devoted to the kinetics and mechanisms of the liquefaction process itself and the influence of the liquefaction solvents.

  18. Linear System Identification in the Short-Time Fourier Transform Domain

    Microsoft Academic Search

    Yekutiel Avargel; Israel Cohen

    Identification of linear systems in the short-time Fourier transform (STFT) domain has been studied extensively, and many\\u000a efficient algorithms have been proposed for that purpose. In this chapter, we introduce three models for linear system identification\\u000a in the STFT domain, and investigate the influence of model order on the estimation accuracy. The first model, which forms\\u000a a perfect STFT representation

  19. Comparison of short-term rainfall prediction models for real-time flood forecasting

    Microsoft Academic Search

    E. Toth; A. Brath; A. Montanari

    2000-01-01

    This study compares the accuracy of the short-term rainfall forecasts obtained with time-series analysis techniques, using past rainfall depths as the only input information. The techniques proposed here are linear stochastic auto-regressive moving-average (ARMA) models, artificial neural networks (ANN) and the non-parametric nearest-neighbours method. The rainfall forecasts obtained using the considered methods are then routed through a lumped, conceptual, rainfallrunoff

  20. Short-time Enhancement of the Decay of Coherent Excitations in Bose-Einstein Condensates

    SciTech Connect

    Bar-Gill, Nir; Rowen, Eitan E.; Kurizki, Gershon; Davidson, Nir [Weizmann Institute of Science, Rehovot 76100 (Israel)

    2009-03-20

    We study, both experimentally and theoretically, short-time modifications of the decay of excitations in a Bose-Einstein Condensate (BEC) embedded in an optical lattice. Strong enhancement of the decay is observed compared to the Golden Rule results. This enhancement of decay increases with the lattice depth. It indicates that the description of decay modifications of few-body quantum systems also holds for decay of many-body excitations of a BEC.

  1. Short-time transport properties in dense suspensions: from neutral to charge-stabilized colloidal spheres.

    PubMed

    Banchio, Adolfo J; Ngele, Gerhard

    2008-03-14

    We present a detailed study of short-time dynamic properties in concentrated suspensions of charge-stabilized and of neutral colloidal spheres. The particles in many of these systems are subject to significant many-body hydrodynamic interactions. A recently developed accelerated Stokesian dynamics (ASD) simulation method is used to calculate hydrodynamic functions, wave-number-dependent collective diffusion coefficients, self-diffusion and sedimentation coefficients, and high-frequency limiting viscosities. The dynamic properties are discussed in dependence on the particle concentration and salt content. Our ASD simulation results are compared with existing theoretical predictions, notably those of the renormalized density fluctuation expansion method of Beenakker and Mazur [Physica A 126, 349 (1984)], and earlier simulation data on hard spheres. The range of applicability and the accuracy of various theoretical expressions for short-time properties are explored through comparison with the simulation data. We analyze, in particular, the validity of generalized Stokes-Einstein relations relating short-time diffusion properties to the high-frequency limiting viscosity, and we point to the distinctly different behavior of de-ionized charge-stabilized systems in comparison to hard spheres. PMID:18345924

  2. Dragon curves revisited S. Tabachnikov

    E-print Network

    Tabachnikov, Sergei

    Dragon curves revisited S. Tabachnikov It has happened several times in recent history mathematical object of comparable beauty, the Dragon curves, whose theory was created by Chandler Davis with previously unpublished addendum).1 Mathematical Intelligencer wrote about Dragon curves more than 30 years

  3. On the Relative Importance of the Short-Time Magnitude and Phase Spectra Towards Speaker Dependent Information

    E-print Network

    On the Relative Importance of the Short-Time Magnitude and Phase Spectra Towards Speaker Dependent investigate the relative contribution of the short-time magnitude and phase spectra towards speaker dependent a human speaker verification experiment that uses phase-only and magnitude-only stimuli. The stimuli

  4. 1628 IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 16, NO. 6, JUNE 2007 A Short-Time Beltrami Kernel for

    E-print Network

    Kimmel, Ron

    1628 IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 16, NO. 6, JUNE 2007 A Short- Time Beltrami Kernel--We introduce a short-time kernel for the Beltrami image enhancing flow. The flow is implemented by "convolving of the kernel gives a better geometrical understanding of the Beltrami flow and shows that the bilateral filter

  5. Short-time universal scaling in an isolated quantum system after a quench

    NASA Astrophysics Data System (ADS)

    Chiocchetta, Alessio; Tavora, Marco; Gambassi, Andrea; Mitra, Aditi

    2015-06-01

    Renormalization-group methods provide a viable approach for investigating the emergent collective behavior of classical and quantum statistical systems in both equilibrium and nonequilibrium conditions. Within this approach we investigate here the dynamics of an isolated quantum system represented by a scalar ?4 theory after a global quench of the potential close to a dynamical critical point. We demonstrate that, within a prethermal regime, the time dependence of the relevant correlations is characterized by a short-time universal exponent, which we calculate at the lowest order in a dimensional expansion.

  6. Fingerprint enhancement revisited and the effects of blood enhancement chemicals on subsequent profiler Plus fluorescent short tandem repeat DNA analysis of fresh and aged bloody fingerprints.

    PubMed

    Frgeau, C J; Germain, O; Fourney, R M

    2000-03-01

    This study was aimed at determining the effect of seven blood enhancement reagents on the subsequent Profiler Plus fluorescent STR DNA analysis of fresh or aged bloody fingerprints deposited on various porous and nonporous surfaces. Amido Black, Crowle's Double Stain. 1,8-diazafluoren-9-one (DFO), Hungarian Red, leucomalachite green, luminol and ninhydrin were tested on linoleum, glass, metal, wood (pine, painted white), clothing (85% polyester/15% cotton, 65% polyester/35% cotton, and blue denim) and paper (Scott 2-ply and Xerox-grade). Preliminary experiments were designed to determine the optimal blood dilutions to use to ensure a DNA typing result following chemical enhancement. A 1:200 blood dilution deposited on linoleum and enhanced with Crowle's Double Stain generated enough DNA for one to two rounds of Profiler Plus PCR amplification. A comparative study of the DNA yields before and after treatment indicated that the quantity of DNA recovered from bloody fingerprints following enhancement was reduced by a factor of 2 to 12. Such a reduction in the DNA yields could potentially compromise DNA typing analysis in the case of small stains. The blood enhancement chemicals selected were also evaluated for their capability to reveal bloodmarks on the various porous and nonporous surfaces chosen in this study. Luminol. Amido Black and Crowle's Double Stain showed the highest sensitivity of all seven chemicals tested and revealed highly diluted (1:200) bloody fingerprints. Both luminol and Amido Black produced excellent results on both porous and nonporous surfaces, but Crowle's Double Stain failed to produce any results on porous substrates. Hungarian Red, DFO, leucomalachite green and ninhydrin showed lower sensitivities. Enhancement of bloodmarks using any of the chemicals selected, and short-term exposure to these same chemicals (i.e., less than 54 days), had no adverse effects on the PCR amplification of the nine STR systems surveyed (D3S 1358, HumvWA, HumFGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820) or of the gender determination marker Amelogenin. The intensity of the fluorescent signals was very similar and the allele size measurements remained constant and identical to those of untreated bloody fingerprints. No additional background fluorescence was noted. Continuous exposure (for 54 days) to two of the seven enhancement chemicals selected (i.e., Crowle's Double Stain and Hungarian Red) slightly reduced the amplification efficiency of the longer STR loci in profiles of fresh and 7 to 14-day-old bloodprints. This suggests that long-term exposure to these chemicals possibly affects the integrity of the DNA molecules. This study indicates that significant evidence can be obtained from fresh or aged bloody fingerprints applied to a variety of absorbent and nonabsorbent surfaces which are exposed to different enhancement chemicals for short or long periods of time. It also reaffirms that PCR STR DNA typing procedures are robust and provide excellent results when used in concert with fluorescence-based detection assays after fingerprint identification has taken place. PMID:10782955

  7. Multi-physics investigation on the failure mechanism and short-time scale wave motion in flip-chip configuration

    E-print Network

    Oh, Yoonchan

    2005-11-01

    thermal stresses and improving solder joint fatigue performance in thermal cycling tests of long-time scale, underfill material viscoelasticity was found to be insignificant in attenuating short-time scale wave propagation. On the other hand...

  8. Time-domain front-end for short time windowing UWB WLAN transform-domain receiver

    Microsoft Academic Search

    Mohamed ZEBDI; Daniel MASSICOTTE; C. J. B. Fayomi

    2009-01-01

    This paper addresses the selectivity problem, for the ultra-wide band (UWB), transform-domain receiver loss of orthogonality. A novel selective time-domain direct-sequence front-end for transform-domain ultra-wideband (UWB) wireless local area network (WLAN) receiver is proposed. The architecture comprises a multi-block, linear, dynamic feedback low-noise amplifier (LNA), quadrature mixer, and baseband filter. The dynamic feedback with inductive output load reduces the LNA

  9. Flow characteristics of a pilot-scale high temperature, short time pasteurizer.

    PubMed

    Tomasula, P M; Kozempel, M F

    2004-09-01

    In this study, we present a method for determining the fastest moving particle (FMP) and residence time distribution (RTD) in a pilot-scale high temperature, short time (HTST) pasteurizer to ensure that laboratory or pilot-scale HTST apparatus meets the Pasteurized Milk Ordinance standards for pasteurization of milk and can be used for obtaining thermal inactivation data. The overall dimensions of the plate in the pasteurizer were 75 x 115 mm, with a thickness of 0.5 mm and effective diameter of 3.0 mm. The pasteurizer was equipped with nominal 21.5- and 52.2-s hold tubes, and flow capacity was variable from 0 to 20 L/h. Tracer studies were used to determine FMP times and RTD data to establish flow characteristics. Using brine milk as tracer, the FMP time for the short holding section was 18.6 s and for the long holding section was 36 s at 72 degrees C, compared with the nominal times of 21.5 and 52.2 s, respectively. The RTD study indicates that the short hold section was 45% back mixed and 55% plug flow for whole milk at 72 degrees C. The long hold section was 91% plug and 9% back mixed for whole milk at 72 degrees C. This study demonstrates that continuous laboratory and pilot-scale pasteurizers may be used to study inactivation of microorganisms only if the flow conditions in the holding tube are established for comparison with commercial HTST systems. PMID:15375033

  10. Use of extremely short Frster resonance energy transfer probes in real-time polymerase chain reaction

    PubMed Central

    Kutyavin, Igor V.

    2013-01-01

    Described in the article is a new approach for the sequence-specific detection of nucleic acids in real-time polymerase chain reaction (PCR) using fluorescently labeled oligonucleotide probes. The method is based on the production of PCR amplicons, which fold into dumbbell-like secondary structures carrying a specially designed probe-luring sequence at their 5? ends. Hybridization of this sequence to a complementary anchoring tail introduced at the 3? end of a fluorescent probe enables the probe to bind to its target during PCR, and the subsequent probe cleavage results in the florescence signal. As it has been shown in the study, this amplicon-endorsed and guided formation of the probe-target duplex allows the use of extremely short oligonucleotide probes, up to tetranucleotides in length. In particular, the short length of the fluorescent probes makes possible the development of a universal probe inventory that is relatively small in size but represents all possible sequence variations. The unparalleled cost-effectiveness of the inventory approach is discussed. Despite the short length of the probes, this new method, named Angler real-time PCR, remains highly sequence specific, and the results of the study indicate that it can be effectively used for quantitative PCR and the detection of polymorphic variations. PMID:24013564

  11. Nonlinear response of vessel walls due to short-time thermomechanical loading

    SciTech Connect

    Pfeiffer, P.A.; Kulak, R.F.

    1994-06-01

    Maintaining structural integrity of the reactor pressure vessel (RPV) during a postulated core melt accident is an important safety consideration in the design of the vessel. This study addresses the failure predictions of the vessel due to thermal and pressure loadings fro the molten core debris depositing on the lower head of the vessel. Different loading combinations were considered based on the dead load, yield stress assumptions, material response and internal pressurization. The analyses considered only short term failure (quasi static) modes, long term failure modes were not considered. Short term failure modes include plastic instabilities of the structure and failure due to exceeding the failure strain. Long term failure odes would be caused by creep rupture that leads to plastic instability of the structure. Due to the sort time durations analyzed, creep was not considered in the analyses presented.

  12. [Study of new XeCl laser with short duration time and preionzation at high pressure].

    PubMed

    Ren, Ren; Chen, Chang-Le; Xu, Jin; Zhu, Shi-Hua; Jing, Ke-Xin; Ren, Da-Nan; Wang, Yong-Cang; Yuan, Xiao; Song, Zhou-Mo

    2005-05-01

    New short duration time XeCI excimer laser has been generated at high pressure within a large volume in order to apply it to he interaction between laser and material, and material plasma study. The laser spectrum exhibits two laser lines at 307.98 and 308.19 nm, which is realized in the proportion of HCl:Xe: He = 0.1% :1% : 98.9% through UV preionization. Theoretic analysis indicated that the maximum intensity loop is B to X grade. Not only UV preionization, glow discharge and the calculation of dynamic equation, but also the laser spectrum and pulse duration time measurement were carried out. It is shown that the duration time decreases and pulse energy rises with the increase in the pressure and discharge voltage. The minimum duration time exceeds 13 ns, the pulse energy is 450 mJ, and the beam divergence angle is 3 mrad. PMID:16128052

  13. A Short-Term Outcome Evaluation of the "I'm Special" Drug Abuse Prevention Program: A Revisit Using SCAT Inventory.

    ERIC Educational Resources Information Center

    Kim, Sehwan; And Others

    1990-01-01

    Examines short-term outcome of "I'm Special" drug abuse prevention/education program to establish a link with what has been observed longitudinally. Administered Self-Concept Attitudinal (SCAT) Inventory to 270 third grade students before and after program. Determined program was able to generate positive changes along six SCAT attitudinal

  14. Modeling circadian and sleep-homeostatic effects on short-term interval timing.

    PubMed

    Spti, Jakub; Aritake, Sayaka; Meyer, Andrea H; Kitamura, Shingo; Hida, Akiko; Higuchi, Shigekazu; Moriguchi, Yoshiya; Mishima, Kazuo

    2015-01-01

    Short-term interval timing i.e., perception and action relating to durations in the seconds range, has been suggested to display time-of-day as well as wake dependent fluctuations due to circadian and sleep-homeostatic changes to the rate at which an underlying pacemaker emits pulses; pertinent human data being relatively sparse and lacking in consistency however, the phenomenon remains elusive and its mechanism poorly understood. To better characterize the putative circadian and sleep-homeostatic effects on interval timing and to assess the ability of a pacemaker-based mechanism to account for the data, we measured timing performance in eighteen young healthy male subjects across two epochs of sustained wakefulness of 38.67 h each, conducted prior to (under entrained conditions) and following (under free-running conditions) a 28 h sleep-wake schedule, using the methods of duration estimation and duration production on target intervals of 10 and 40 s. Our findings of opposing oscillatory time courses across both epochs of sustained wakefulness that combine with increasing and, respectively, decreasing, saturating exponential change for the tasks of estimation and production are consistent with the hypothesis that a pacemaker emitting pulses at a rate controlled by the circadian oscillator and increasing with time awake determines human short-term interval timing; the duration-specificity of this pattern is interpreted as reflecting challenges to maintaining stable attention to the task that progressively increase with stimulus magnitude and thereby moderate the effects of pacemaker-rate changes on overt behavior. PMID:25741253

  15. Short early filling deceleration time on day 1after acute myocardial infarction is associated with short and long term left ventricular remodelling

    PubMed Central

    Otasevic, P; Neskovic, A; Popovic, Z; Vlahovic, A; Bojic, D; Bojic, M; Popovic, A

    2001-01-01

    OBJECTIVETo assess the relations between early filling deceleration time, left ventricular remodelling, and cardiac mortality in an unselected group of postinfarction patients.?DESIGN AND PATIENTSProspective evaluation of 131consecutive patients with first acute myocardial infarction. Echocardiography was performed on day 1,day 2,day 3,day 7,at three and six weeks, and at three, six, and 12months after infarction. According to deceleration time on day 1,patients were divided into groups with short (< 150ms) and normal deceleration time (?150 ms).?SETTINGTertiary care centre.?RESULTSPatients with a short deceleration time had higher end systolic and end diastolic volume indices and a higher wall motion score index, but a lower ejection fraction, in the year after infarction. These patients also showed a significant increase in end diastolic (p<0.001) and end systolic volume indices (p =0.007) during the follow up period, while ejection fraction and wall motion score index remained unchanged. In the group with normal deceleration time, end diastolic volume index increased (p<0.001) but end systolic volume index did not change; in addition, the ejection fraction increased (p=0.002) and the wall motion score index decreased (p<0.001). One year and five year survival analysis showed greater cardiac mortality in patients with a short deceleration time (p=0.04 and p=0.02, respectively). In a Cox model, which included initial ejection fraction, infarct location, and infarct size, deceleration time on day 1was the only significant predictor of five year mortality.?CONCLUSIONSA short deceleration time on day 1after acute myocardial infarction can identify patients who are likely to undergo left ventricular remodelling in the following year. These patients have a higher one year and five year cardiac mortality.???Keywords: deceleration time; left ventricular remodelling; acute myocardial infarction PMID:11303004

  16. Fast detection of nonlinearity and nonstationarity in short and noisy time series

    E-print Network

    M. De Domenico; V. Latora

    2010-07-07

    We introduce a statistical method to detect nonlinearity and nonstationarity in time series, that works even for short sequences and in presence of noise. The method has a discrimination power similar to that of the most advanced estimators on the market, yet it depends only on one parameter, is easier to implement and faster. Applications to real data sets reject the null hypothesis of an underlying stationary linear stochastic process with a higher confidence interval than the best known nonlinear discriminators up to date.

  17. Short time effect of Delta oscillation under microcurrent transcutaneous electrical nerve stimulation at ST36.

    PubMed

    Li, Shunan; Li, Donghui; Li, Huiyan; Wang, Jiang

    2014-01-01

    This paper was to study the short time effect of Delta brain oscillation under microcurrent transcutaneous electrical nerve stimulation (MTENS) at ST36 (Zusanli). The 64-channal electroencephalograph (EEG) signals from 12 healthy volunteers were recorded including baseline stage, during stimulation and after stimulation. Autoregressive (AR) Burg method was used to estimate the power spectrum. Then power variation rate (PVR) was calculated to quantify the effects compared with the baseline in Delta band. The results showed that MTENS at ST36 on right side led to increased Delta band power in left frontal. PMID:25571012

  18. Time of flight emission spectroscopy of laser produced nickel plasma: Short-pulse and ultrafast excitations

    SciTech Connect

    Smijesh, N.; Chandrasekharan, K. [Laser and Nonlinear Optics Laboratory, Department of Physics, National Institute of Technology Calicut, Calicut 673601 (India); Joshi, Jagdish C.; Philip, Reji, E-mail: reji@rri.res.in [Ultrafast and Nonlinear Optics Lab, Light and Matter Physics Group, Raman Research Institute, Bangalore 560080 (India)

    2014-07-07

    We report the experimental investigation and comparison of the temporal features of short-pulse (7 ns) and ultrafast (100 fs) laser produced plasmas generated from a solid nickel target, expanding into a nitrogen background. When the ambient pressure is varied in a large range of 10??Torr to 10Torr, the plume intensity is found to increase rapidly as the pressure crosses 1 Torr. Time of flight (TOF) spectroscopy of emission from neutral nickel (Ni I) at 361.9 nm (3d?(D) 4p ? 3d?(D) 4s transition) reveals two peaks (fast and slow species) in short-pulse excitation and a single peak in ultrafast excitation. The fast and slow peaks represent recombined neutrals and un-ionized neutrals, respectively. TOF emission from singly ionized nickel (Ni II) studied using the 428.5 nm (3p?3d?(P) 4s? 3p?3d? 4s) transition shows only a single peak for either excitation. Velocities of the neutral and ionic species are determined from TOF measurements carried out at different positions (i.e., at distances of 2 mm and 4 mm, respectively, from the target surface) on the plume axis. Measured velocities indicate acceleration of neutrals and ions, which is caused by the Coulomb pull of the electrons enveloping the plume front in the case of ultrafast excitation. Both Coulomb pull and laser-plasma interaction contribute to the acceleration in the case of short-pulse excitation. These investigations provide new information on the pressure dependent temporal behavior of nickel plasmas produced by short-pulse and ultrafast laser pulses, which have potential uses in applications such as pulsed laser deposition and laser-induced nanoparticle generation.

  19. Alterations of Visual Reaction Time and Short Term Memory in Military Radar Personnel

    PubMed Central

    MORTAZAVI, Seyed Mohammad Javad; TAEB, Shahram; DEHGHAN, Naser

    2013-01-01

    Background Radar transmitters emit high-power radiofrequency radiation by creation of a high-voltage and high-frequency alternating electrical current. Methods: Health effects of occupational exposure to military radar were investigated. Visual reaction time was recorded with a simple blind computer-assisted-visual reaction time test. To assess the short-term memory, modified Wechsler Memory Scale test was performed. Results: The mean +/- SD reaction time in radar works (N=100) and the control group (N=57) were 238.58 +/? 23.47 milliseconds and 291.86 +/? 28.26 milliseconds (P<0.0001), respectively. The scores of forward digit span in radar works and the control group were 3.56 +/? 0.77 and 4.29 +/? 1.06 (P<0.0001), while the scores of backward digit span in radar works and the control group were 2.70 +/? 0.69 and 3.62 +/? 0.95 (P<0.0001). The scores of word recognition in radar works and the control group were 3.37 +/? 1.13 and 5.86 +/? 1.11 (P<0.0001). Finally, the scores of paired words in radar works and the control group were 13.56 +/? 1.78 and 15.21 +/? 2.20 (P<0.0001). It can be concluded that occupational exposures to radar radiations decreases reaction time, which may lead to a better response to different hazards. Conclusion: To the best of our knowledge, this is the first study to show that occupational exposure to radar microwave radiation leads to decreased reaction time and the lower performance of short-term memory. Altogether, these results indicate that occupational exposure to radar microwave radiations may be linked to some non-detrimental and detrimental health effects. PMID:23785684

  20. Short-term earthquake risk assessment considering time-dependent b-values

    NASA Astrophysics Data System (ADS)

    Gulia, Laura; Tormann, Thessa; Wiemer, Stefan

    2015-04-01

    Observations from laboratory experiments measuring acoustic emissions during loading cycles in pressurized rock samples have repeatedly suggested that small events in the precursory phase of an impending large event change in their relative size distribution. In particular, they highlight a systematic b-value decrease during the stress increase period before the main event. A number of large natural events, but not all of them, have been shown to have a precursory decrease in the b-value at very different time scales, from months to a few days before the subsequent mainshock. At present short term-forecast models such as STEP and ETAS consider the generic probability that an event can trigger subsequent seismicity in the near field; the rate increasing during the foreshock sequences can offer a probability gain for a significant earthquake to happen. While the probability gain of a stationary Poissonian background is substantial, selected case studies have shown through cost-benefit analysis that the absolute probability remains too low to warrant actions. This was shown for example by van Stiphout et al. (2010, GRL), for the 2009 a Mw 6.3 earthquake that hit the city of L'Aquila (Central Italy) after three months of foreshock activity. We here analyze the probability gain of a novel generation of short term forecast models which considers both the change in the seismicity rates and the temporal changes in the b-value. Changes in earthquake probability are then translated also into time-dependent hazard and risk. Preliminary results suggest that the precursory b-value decrease in the L'Aquila case results in an additional probability increase of a M6.3 event of about a factor of 30-50, which then surpasses the cost-benefit threshold for short-term evacuation in selected cases.

  1. Acceleration of proliferative response of mouse fibroblasts by short-time pretreatment with polyphenols.

    PubMed

    Tsuruya, Makoto; Niwano, Yoshimi; Nakamura, Keisuke; Kanno, Taro; Nakashima, Takuji; Egusa, Hiroshi; Sasaki, Keiichi

    2014-11-01

    Under the hypothesis that photo-irradiated proanthocyanidin could accelerate wound healing through reactive oxygen species (ROS) formation, we examined the effect of proanthocyanidin on 3T3-L1 mouse fibroblasts with or without photo-irradiation. As a result, irrespective of presence or absence of photo-irradiation, only 1 min exposure of the cells to proanthocyanidin resulted in accelerated proliferation of the cells in a concentration-dependent manner. Similarly to proanthocyanidin, 1 min pretreatment with catechin, caffeic acid, and chlorogenic acid accelerated the proliferative response, but gallic acid, epicatechin gallate, epigallocatechin, and epigallocatechin gallate failed. If incorporated active ingredient such as proanthocyanidin for such a short time as 1 min accelerates the proliferation response, a bioassay was conducted by utilizing antioxidant potential of proanthocyanidin. That is, intracellular oxidation of 2',7'-dichlorodihydrofluorescin induced by H2O2 was significantly inhibited when the cells were pretreated with proanthocyanidin for 1 min, suggesting that incorporated proanthocyanidin into the cells exerted antioxidant effect. This was also supported by a liquid chromatography/mass spectrometry analysis in which incorporation of proanthocyanidin components such as catechin monomers and dimers into the cells within 1 min was confirmed. These results suggest that active polyphenolic compounds such as proanthocyanidin, catechin, caffeic acid, and chlorogenic acid incorporated into the cells in such a short time as 1 min could accelerate the proliferative response of the cells. PMID:25173673

  2. Orientation relaxation in glassy polymers. II. Dipole-size spectroscopy and short-time kinetics

    NASA Astrophysics Data System (ADS)

    Patashinski, Alexander Z.; Ratner, Mark A.

    1995-12-01

    The orientational diffusion of a rodlike particle embedded in a glassy polymeric matrix is considered; the underlying kinetics is that of local rearrangements. A defining parameter of the theory is the length of the particle. The timing of steps of the random walk in orientation space is determined by rearrangements. We discuss the physical properties of the glass state in connection with the rearrangement kinetics. The orientational diffusion is influenced by the local disorder; this influence is different for dipoles of different length. For a short dipole, the resulting diffusion is of generalized Debye type. Nonexponential relaxation of physical quantities may then be caused by the distribution of rearrangement barriers. For longer dipoles and if the orientation is uniquely determined by the configuration of the embedding cluster, the motion is a random walk on a given random map on a sphere. An ensemble of random mappings is considered. For even longer dipoles, hierarchical (multiscale) relaxation is expected. We discuss the relation of the theory to the short time depoling kinetics in a system of dipoles having different length, such as are found in relaxation of electrically poled polymer materials.

  3. Short-time transport properties of bidisperse suspensions and porous media: A Stokesian dynamics study

    NASA Astrophysics Data System (ADS)

    Wang, Mu; Brady, John F.

    2015-03-01

    We present a comprehensive computational study of the short-time transport properties of bidisperse hard-sphere colloidal suspensions and the corresponding porous media. Our study covers bidisperse particle size ratios up to 4 and total volume fractions up to and beyond the monodisperse hard-sphere close packing limit. The many-body hydrodynamic interactions are computed using conventional Stokesian Dynamics (SD) via a Monte-Carlo approach. We address suspension properties including the short-time translational and rotational self-diffusivities, the instantaneous sedimentation velocity, the wavenumber-dependent partial hydrodynamic functions, and the high-frequency shear and bulk viscosities and porous media properties including the permeability and the translational and rotational hindered diffusivities. We carefully compare the SD computations with existing theoretical and numerical results. For suspensions, we also explore the range of validity of various approximation schemes, notably the pairwise additive approximations with the Percus-Yevick structural input. We critically assess the strengths and weaknesses of the SD algorithm for various transport properties. For very dense systems, we discuss in detail the interplay between the hydrodynamic interactions and the structures due to the presence of a second species of a different size.

  4. Non-monotonous short-time decay of the Loschmidt echo in quasi-one-dimensional systems

    E-print Network

    Arseni Goussev

    2011-05-16

    We study the short-time stability of quantum dynamics in quasi-one-dimensional systems with respect to small localized perturbations of the potential. To this end, we address, analytically and numerically, the decay of the Loschmidt echo (LE) during times short compared to the Ehrenfest time. We find that the LE is generally a non-monotonous function of time and exhibits strongly pronounced minima and maxima at the instants of time when the corresponding classical particle traverses the perturbation region. We also show that, under general conditions, the envelope decay of the LE is well approximated by a Gaussian, and we derive explicit analytical formulas for the corresponding decay time. Finally, we demonstrate that the observed non-monotonicity of the LE decay is only pertinent to one-dimensional (and, more generally, quasi-one-dimensional systems), and that the short-time decay of the LE can be monotonous in higher number of dimensions.

  5. Non-monotonous short-time decay of the Loschmidt echo in quasi-one-dimensional systems

    E-print Network

    Goussev, Arseni

    2011-01-01

    We study the short-time stability of quantum dynamics in quasi-one-dimensional systems with respect to small localized perturbations of the potential. To this end, we address, analytically and numerically, the decay of the Loschmidt echo (LE) during times short compared to the Ehrenfest time. We find that the LE is generally a non-monotonous function of time and exhibits strongly pronounced minima and maxima at the instants of time when the corresponding classical particle traverses the perturbation region. We also show that, under general conditions, the envelope decay of the LE is well approximated by a Gaussian, and we derive explicit analytical formulas for the corresponding decay time. Finally, we demonstrate that the observed non-monotonicity of the LE decay is only pertinent to one-dimensional (and, more generally, quasi-one-dimensional systems), and that the short-time decay of the LE can be monotonous in higher number of dimensions.

  6. Effects of Diffusion Time on Short-Range Hyperpolarized 3He Diffusivity Measurements in Emphysema

    SciTech Connect

    Gierada, David S.; Woods, Jason C.; Bierhals, Andrew J.; Bartel, Seth T.; Ritter, Jon H.; Choong, Cliff K.; Das, Nitin A.; Hong, Cheng; Pilgram, Thomas K.; Chang, Yulin V.; Jacob, Rick E.; Hogg, James C.; Battafarano, Richard J.; Cooper, Joel D.; Meyers, Bryan F.; Patterson, G Alexander; Yablonskiy, Dmitriy A.; Conradi, Mark S.

    2009-09-28

    Purpose: To characterize the effect of diffusion time on short-range hyperpolarized 3He MR diffusion measurements across a wide range of emphysema severity. Materials and Methods: 3He diffusion MR imaging was performed on 19 lungs or lobes resected from 18 subjects with varying degrees of emphysema using 3 diffusion times (1.6 msec, 5 msec, and 10 msec) at constant b value. Emphysema severity was quantified as the mean apparent diffusion coefficient (ADC) and as the percentage of pixels with ADC higher than multiple thresholds from 0.30-0.55 cm2/sec (ADC index). Quantitative histology (mean linear intercept) was obtained in 10 of the lung specimens from 10 of the subjects. Results: The mean ADCs with diffusion times of 1.6, 5.0, and 10.0 msec were 0.46, 0.40, and 0.37 cm2/sec, respectively (P <0.0001, ANOVA). There was no relationship between the ADC magnitude and the effect of diffusion time on ADC values. Mean linear intercept correlated with ADC (r=0.91-0.94, P<0.001) and ADC index (r=0.78-0.92, P<0.01) at all diffusion times.

  7. Night-time evaporation from a short-rotation willow stand

    NASA Astrophysics Data System (ADS)

    Iritz, Zinaida; Lindroth, Anders

    1994-05-01

    The aim of the present study was to quantify and analyse the evaporation during night-time in a willow ( Salix viminalis L.) short-rotation stand. Evaporation measurements were made throughout the 24 h period on 76 days during the 1988 growing season using the energy-balance/Bowen-ratio method. Canopy conductance was estimated using a rearranged form of the Penman combination equation. The mean hourly evaporation rate during daytime was 0.18 mm h -1 and the corresponding value during night-time was 0.013 mm h -1, about 7% of the daytime rate. The mean cumulative night-time evaporation was 0.12 mm per night or 4.3% of the mean daytime evaporation. The highest night-time evaporation occurred in September and October with 0.21 mm and 0.36 mm per night, respectively, some 30-35% of the daytime evaporation during these periods. Total night-time evaporation for the growing season was estimated as 21 mm. Night-time evaporation was controlled mainly by vapour pressure deficit and ventilation whereas net radiation had only a minor influence. The night-time canopy resistance was estimated for a shorter period when the canopy was completely closed (leaf area index around 5) and the soil evaporation could be assumed negligible. The canopy resistance ranged between 10 and 220 s m -1 depending on vapour pressure deficit. The dependence on vapour pressure deficit during night-time was similar to the dependence during daytime but with a much larger sensitivity during the dark period.

  8. EXPLORING THE POTENTIAL OF SHORT-TIME FOURIER TRANSFORMS FOR ANALYZING SKIN CONDUCTANCE AND PUPILLOMETRY IN REAL-TIME APPLICATIONS

    SciTech Connect

    Roger Lew; Brian P. Dyre; Steffen Werner; Jeffrey C. Joe; Brian Wotring; Tuan Tran

    2008-09-01

    The development of real-time predictors of mental workload is critical for the practical application of augmented cognition to human-machine systems. This paper explores a novel method based on a short-time Fourier transform (STFT) for analyzing galvanic skin conductance (SC) and pupillometry time-series data to extract estimates of mental workload with temporal bandwidth high-enough to be useful for augmented cognition applications. We tested the method in the context of a process control task based on the DURESS simulation developed by Vincente and Pawlak (1994; ported to Java by Cosentino,& Ross, 1999). SC, pupil dilation, blink rate, and visual scanning patterns were measured for four participants actively engaged in controlling the simulation. Fault events were introduced that required participants to diagnose errors and make control adjustments to keep the simulator operating within a target range. We were interested in whether the STFT of these measures would produce visible effects of the increase in mental workload and stress associated with these events. Graphical exploratory data analysis of the STFT showed visible increases in the power spectrum across a range of frequencies directly following fault events. We believe this approach shows potential as a relatively unobtrusive, low-cost, high bandwidth measure of mental workload that could be particularly useful for the application of augmented cognition to human-machine systems.

  9. Structure and short-time dynamics in concentrated suspensions of charged colloids.

    PubMed

    Westermeier, Fabian; Fischer, Birgit; Roseker, Wojciech; Grbel, Gerhard; gele, Gerhard; Heinen, Marco

    2012-09-21

    We report a comprehensive joint experimental-theoretical study of the equilibrium pair-structure and short-time diffusion in aqueous suspensions of highly charged poly-acrylate (PA) spheres in the colloidal fluid phase. Low-polydispersity PA sphere systems with two different hard-core radii, R(0) = 542 and 1117 A?, are explored over a wide range of concentrations and salinities using static and dynamic light scattering (DLS), small angle x-ray scattering, and x-ray photon correlation spectroscopy (XPCS). The measured static and dynamic scattering functions are analyzed using state-of-the-art theoretical methods. For all samples, the measured static structure factor, S(Q), is in good agreement with results by an analytical integral equation method for particles interacting by a repulsive screened Coulomb plus hard-core pair potential. In our DLS and XPCS measurements, we have determined the short-time diffusion function D(Q) = D(0)?H(Q)?S(Q), comprising the free diffusion coefficient D(0) and the hydrodynamic function H(Q). The latter is calculated analytically using a self-part corrected version of the ??-scheme by Beenakker and Mazur which accounts approximately for many-body hydrodynamic interactions (HIs). Except for low-salinity systems at the highest investigated volume fraction ? ? 0.32, the theoretical predictions for H(Q) are in excellent agreement with the experimental data. In particular, the increase in the collective diffusion coefficient D(c) = D(Q ? 0), and the decrease of the self-diffusion coefficient, D(s) = D(Q ? ?), with increasing ? is well described. In accord with the theoretical prediction, the peak value, H(Q(m)), of H(Q) relates to the nearest neighbor cage size ?2??Q(m), for which concentration scaling relations are discussed. The peak values H(Q(m)) are globally bound from below by the corresponding neutral hard-spheres peak values, and from above by the limiting peak values for low-salinity charge-stabilized systems. HIs usually slow short-time diffusion on colloidal length scales, except for the cage diffusion coefficient, D(cge) = D(Q(m)), in dilute low-salinity systems where a speed up of the system dynamics and corresponding peak values of H(Q(m)) > 1 are observed experimentally and theoretically. PMID:22998268

  10. Structure and short-time dynamics in concentrated suspensions of charged colloids

    NASA Astrophysics Data System (ADS)

    Westermeier, Fabian; Fischer, Birgit; Roseker, Wojciech; Grbel, Gerhard; Ngele, Gerhard; Heinen, Marco

    2012-09-01

    We report a comprehensive joint experimental-theoretical study of the equilibrium pair-structure and short-time diffusion in aqueous suspensions of highly charged poly-acrylate (PA) spheres in the colloidal fluid phase. Low-polydispersity PA sphere systems with two different hard-core radii, R0 = 542 and 1117 , are explored over a wide range of concentrations and salinities using static and dynamic light scattering (DLS), small angle x-ray scattering, and x-ray photon correlation spectroscopy (XPCS). The measured static and dynamic scattering functions are analyzed using state-of-the-art theoretical methods. For all samples, the measured static structure factor, S(Q), is in good agreement with results by an analytical integral equation method for particles interacting by a repulsive screened Coulomb plus hard-core pair potential. In our DLS and XPCS measurements, we have determined the short-time diffusion function D(Q) = D0 H(Q)/S(Q), comprising the free diffusion coefficient D0 and the hydrodynamic function H(Q). The latter is calculated analytically using a self-part corrected version of the ??-scheme by Beenakker and Mazur which accounts approximately for many-body hydrodynamic interactions (HIs). Except for low-salinity systems at the highest investigated volume fraction ? ? 0.32, the theoretical predictions for H(Q) are in excellent agreement with the experimental data. In particular, the increase in the collective diffusion coefficient Dc = D(Q ? 0), and the decrease of the self-diffusion coefficient, Ds = D(Q ? ?), with increasing ? is well described. In accord with the theoretical prediction, the peak value, H(Qm), of H(Q) relates to the nearest neighbor cage size 2?/Qm, for which concentration scaling relations are discussed. The peak values H(Qm) are globally bound from below by the corresponding neutral hard-spheres peak values, and from above by the limiting peak values for low-salinity charge-stabilized systems. HIs usually slow short-time diffusion on colloidal length scales, except for the cage diffusion coefficient, Dcge = D(Qm), in dilute low-salinity systems where a speed up of the system dynamics and corresponding peak values of H(Qm) > 1 are observed experimentally and theoretically.

  11. Influence of Ramadan Fasting on Anaerobic Performance and Recovery Following Short time High Intensity Exercise.

    PubMed

    Karli, Umid; Guvenc, Alpay; Aslan, Alper; Hazir, Tahir; Acikada, Caner

    2007-01-01

    The aim of this study was to investigate the effects of Ramadan fasting on anaerobic power and capacity and the removal rate of lactate after short time high intensity exercise in power athletes. Ten male elite power athletes (2 wrestlers, 7 sprinters and 1 thrower, aged 20-24 yr, mean age 22.30 1.25 yr) participated in this study. The subjects were tested three times [3 days before the beginning of Ramadan (Pre-RF), the last 3 days of Ramadan (End-RF) and the last 3 days of the 4(th) week after the end of Ramadan (After-RF)]. Anaerobic power and capacity were measured by using the Wingate Anaerobic Test (WAnT) at Pre-RF, End-RF and After- RF. Capillary blood samples for lactate analyses and heart rate recordings were taken at rest, immediately after WAnT and throughout the recovery period. Repeated measures of ANOVA indicated that there were no significant changes in body weight, body mass index, fat free mass, percentage of body fat, daily sleeping time and daily caloric intake associated with Ramadan fasting. No significant changes were found in total body water either, but urinary density measured at End-RF was significantly higher than After-RF. Similarity among peak HR and peak LA values at Pre-RF, End- RF and After-RF demonstrated that cardiovascular and metabolic stress caused by WAnT was not affected by Ramadan fasting. In addition, no influence of Ramadan fasting on anaerobic power and capacity and removal rate of LA from blood following high intensity exercise was observed. The results of this study revealed that if strength-power training is performed regularly and daily food intake, body fluid balance and daily sleeping time are maintained as before Ramadan, Ramadan fasting will not have adverse effects on body composition, anaerobic power and capacity, and LA metabolism during and after high intensity exercise in power athletes. Key pointsNo significant changes were assessed on body composition, daily sleeping time and caloric intake, and body fluid balance in regularly trained power athletes during Ramadan fasting.Ramadan fasting has no adverse effect on power outputs of short time high intensity exercise.No influence of Ramadan fasting on LA metabolism during high intensity exercise and passive recovery in regularly trained power athletes. PMID:24149483

  12. Super-resolution spectral estimation in short-time non-contact vital sign measurement.

    PubMed

    Sun, Li; Li, Yusheng; Hong, Hong; Xi, Feng; Cai, Weidong; Zhu, Xiaohua

    2015-04-01

    Non-contact techniques for measuring vital signs attract great interest due to the benefits shown in medical monitoring, military application, etc. However, the presence of respiration harmonics caused by nonlinear phase modulation will result in performance degradation. Suffering from smearing and leakage problems, conventional discrete Fourier transform (DFT) based methods cannot distinguish the heartbeat component from closely located respiration harmonics in frequency domain, especially in short-time processing. In this paper, the theory of sparse reconstruction is merged with an extended harmonic model of vital signals, aiming at achieving a super-resolution spectral estimation of vital signals by additionally exploiting the inherent sparse prior information. Both simulated and experimental results show that the proposed algorithm has superior performance to DFT-based methods and the recently applied multiple signal classification algorithm, and the required processing window length has been shortened to 5.12 s. PMID:25933881

  13. Statistics of Particle Trajectories at Short Time Intervals Reveal fN-Scale Colloidal Forces

    E-print Network

    Sunil K. Sainis; Vincent Germain; Eric R. Dufresne

    2007-04-09

    We describe and implement a technique for extracting forces from the relaxation of an overdamped thermal system with normal modes. At sufficiently short time intervals, the evolution of a normal mode is well described by a one-dimensional Smoluchowski equation with constant drift velocity, v, and diffusion coefficient, D. By virtue of fluctuation-dissipation, these transport coefficients are simply related to conservative forces, F, acting on the normal mode: F = k_BT v/D. This relationship implicitly accounts for hydrodynamic interactions, requires no mechanical calibration, makes no assumptions about the form of conservative forces, and requires no prior knowledge of material properties. We apply this method to measure the electrostatic interactions of polymer microspheres suspended in nonpolar microemulsions.

  14. Instantaneous Heart Rate detection using short-time autocorrelation for wearable healthcare systems.

    PubMed

    Nakano, Masanao; Konishi, Toshihiro; Izumi, Shintaro; Kawaguchi, Hiroshi; Yoshimoto, Masahiko

    2012-01-01

    This report describes a robust method of Instantaneous Heart Rate (IHR) detection from noisy electrocardiogram (ECG) signals. Generally, the IHR is calculated from the interval of R-waves. Then, the R-waves are extracted from the ECG using a threshold. However, in wearable biosignal monitoring systems, various noises (e.g. muscle artifacts from myoelectric signals, electrode motion artifacts) increase incidences of misdetection and false detection because the power consumption and electrode distance of the wearable sensor are limited to reduce its size and weight. To prevent incorrect detection, we use a short-time autocorrelation technique. The proposed method uses similarity of the waveform of the QRS complex. Therefore, it has no threshold calculation Process and it is robust for noisy environment. Simulation results show that the proposed method improves the success rate of IHR detection by up to 37%. PMID:23367467

  15. The time of onset of abnormal calcification in spondylometaepiphyseal dysplasia, short limb-abnormal calcification type

    Microsoft Academic Search

    Beyhan Tysz; Nurperi Gazio?lu; Sava? ngr; Dolly Yafet Aji; Seval Trkmen

    2009-01-01

    A 1-month-old boy with shortness of extremities on prenatal US was referred to our department with a provisional diagnosis\\u000a of achondroplasia. His height was normal but he had short extremities and platyspondyly, premature carpal epiphyses on both\\u000a hands, and short tubular bones with irregular metaphyses on radiographs. Re-evaluation of the patient at the age of 1year\\u000a revealed very short height

  16. Proton spectroscopy of human brain with very short echo time using high gradient amplitudes.

    PubMed

    Seeger, U; Klose, U; Seitz, D; Ngele, T; Lutz, O; Grodd, W

    1998-01-01

    In localized proton magnetic resonance spectroscopy very short echo times (TE) are achieved to diminish signal loss due to T2 relaxation and to avoid phase distortions due to J-coupling. A sequence for single volume spectroscopy in human brain is described with a TE as low as 5 ms. Examinations were performed on a 1.5 T whole-body imager with actively shielded gradients. A self-designed stimulated echo acquisition mode (STEAM) sequence with very high amplitude spoiling gradients of 24 mT/m was used to take advantage of the whole potential of the gradient system. Optimization of TE was carried out by controlling spectral quality and localization in both phantom and volunteer measurements. Proton spectra of human brain were acquired in 21 healthy volunteers. Spectra of occipital white matter, parieto-occipital grey/white matter, and cerebellum revealed none or only small eddy current distortions at a TE of 5 ms. The volume of interest was 8-12 ml, repetition time was 1.5 s, and mixing time was 5 ms. Peak ratios of major metabolites referring to creatine were estimated and the relative standard deviations were calculated to determine interindividual reproducibility. The relative standard deviation of myo-inositol ranged from 6% to 11% within these brain regions whereas for glutamine and glutamate 7% to 16% were found. PMID:9436947

  17. Role of Mode-mode Coupling in Short-time Excited State Decay

    NASA Astrophysics Data System (ADS)

    Mensik, Miroslav; Nespurek, Stanislav

    2005-05-01

    Master equation of a relevant electronic and vibrational system is derived for a special diabatic basis corresponding to vertical processes. It is shown that bath modes contribute dynamically to the inter-state coupling only at short times. For long times the bath-induced inter-state coupling is static and increases with the contribution of bath modes to the Stokes shift and to the Herzberg-Teller correction of the excited state. Simultaneously, the time evolution of excited state population is studied numerically for the system consisting of two electronic levels interacting with two vibrational modes, coupled to a heat bath. A mutual coupling of the vibrational modes in the excited state is taken into account (Duschinsky effect). Excited state population relaxes faster if interacting vibrational mode dissipates its energy via vibrational mode of a smaller eigenfrequency. Fast component of excited state depopulation cannot be achieved via coherent mode-mode coupling, if the second mode is not directly coupled to the electronic inter-state transition.

  18. Grief revisited.

    PubMed

    Ng, B Y

    2005-06-01

    The article serves to examine the cultural influences on attitudes towards the deceased and bereaved, as well as on the practice of mourning, and to revisit normal and pathological variants of grief. Grief is a subjective state of psychological and physiological reaction to the loss of a loved one. Reaction to the loss is experienced internally in a uniform manner across cultures. However, mourning, the voluntary social expression of the loss, varies from culture to culture. Rituals provide a standardised mode of behaviour, which helps to relieve the sense of uncertainty or loss. There were reports of ghost sightings involving foreign tourists in the 6 worst-hit southern provinces in Thailand following the tsunami tragedy. This phenomenon of "mass hallucinations" is understandable from the cultural perspective. New models of grief have been developed to account for the individuality and diversity of grief and to encompass the social, behavioural and spiritual dimensions of loss as well as those of the psychological and physical. Clinically, the duration of grief reactions varies widely, depending on the nature of the loss and the connection to the deceased. In the case of the tsunami tragedy, with relatives missing, homes swept away and familiar neighbourhoods turned into wastelands, many victims are likely to have complicated grief. Traumatic grief, which includes a prominent component of separation distress characterised by yearning and searching and frequent "bittersweet" recollections of the deceased, has been associated with long-term dysfunction. Grief work utilising the traumatic grief treatment protocol appears to be a promising intervention. PMID:16021224

  19. Short Gamma-Ray Bursts in the "Time-reversal" Scenario

    NASA Astrophysics Data System (ADS)

    Ciolfi, Riccardo; Siegel, Daniel M.

    2015-01-01

    Short gamma-ray bursts (SGRBs) are among the most luminous explosions in the universe and their origin still remains uncertain. Observational evidence favors the association with binary neutron star or neutron star-black hole (NS-BH) binary mergers. Leading models relate SGRBs to a relativistic jet launched by the BH-torus system resulting from the merger. However, recent observations have revealed a large fraction of SGRB events accompanied by X-ray afterglows with durations ~102-105 s, suggesting continuous energy injection from a long-lived central engine, which is incompatible with the short (lsim 1 s) accretion timescale of a BH-torus system. The formation of a supramassive NS, resisting the collapse on much longer spin-down timescales, can explain these afterglow durations, but leaves serious doubts on whether a relativistic jet can be launched at the merger. Here we present a novel scenario accommodating both aspects, where the SGRB is produced after the collapse of a supramassive NS. Early differential rotation and subsequent spin-down emission generate an optically thick environment around the NS consisting of a photon-pair nebula and an outer shell of baryon-loaded ejecta. While the jet easily drills through this environment, spin-down radiation diffuses outward on much longer timescales and accumulates a delay that allows the SGRB to be observed before (part of) the long-lasting X-ray signal. By analyzing diffusion timescales for a wide range of physical parameters, we find delays that can generally reach ~105 s, compatible with observations. The success of this fundamental test makes this "time-reversal" scenario an attractive alternative to current SGRB models.

  20. Short gamma-ray bursts in the "time-reversal" scenario

    E-print Network

    Riccardo Ciolfi; Daniel M. Siegel

    2015-01-27

    Short gamma-ray bursts (SGRBs) are among the most luminous explosions in the Universe and their origin still remains uncertain. Observational evidence favors the association with binary neutron star or neutron star-black hole (NS-BH) binary mergers. Leading models relate SGRBs to a relativistic jet launched by the BH-torus system resulting from the merger. However, recent observations have revealed a large fraction of SGRB events accompanied by X-ray afterglows with durations $\\sim10^2\\!-\\!10^5~\\mathrm{s}$, suggesting continuous energy injection from a long-lived central engine, which is incompatible with the short ($\\lesssim1~\\mathrm{s}$) accretion timescale of a BH-torus system. The formation of a supramassive NS, resisting the collapse on much longer spin-down timescales, can explain these afterglow durations, but leaves serious doubts on whether a relativistic jet can be launched at merger. Here we present a novel scenario accommodating both aspects, where the SGRB is produced after the collapse of a supramassive NS. Early differential rotation and subsequent spin-down emission generate an optically thick environment around the NS consisting of a photon-pair nebula and an outer shell of baryon-loaded ejecta. While the jet easily drills through this environment, spin-down radiation diffuses outwards on much longer timescales and accumulates a delay that allows the SGRB to be observed before (part of) the long-lasting X-ray signal. By analyzing diffusion timescales for a wide range of physical parameters, we find delays that can generally reach $\\sim10^5~\\mathrm{s}$, compatible with observations. The success of this fundamental test makes this "time-reversal" scenario an attractive alternative to current SGRB models.

  1. Estimating the number of components of a multicomponent nonstationary signal using the short-term time-frequency Rnyi entropy

    NASA Astrophysics Data System (ADS)

    Sucic, Victor; Saulig, Nicoletta; Boashash, Boualem

    2011-12-01

    The time-frequency Rnyi entropy provides a measure of complexity of a nonstationary multicomponent signal in the time-frequency plane. When the complexity of a signal corresponds to the number of its components, then this information is measured as the Rnyi entropy of the time-frequency distribution (TFD) of the signal. This article presents a solution to the problem of detecting the number of components that are present in short-time interval of the signal TFD, using the short-term Rnyi entropy. The method is automatic and it does not require a prior information about the signal. The algorithm is applied on both synthetic and real data, using a quadratic separable kernel TFD. The results confirm that the short-term Rnyi entropy can be an effective tool for estimating the local number of components present in the signal. The key aspect of selecting a suitable TFD is also discussed.

  2. An Electronic Circuit System for Time-Reversal of Ultra-Wideband Short Impulses Based on Frequency-Domain Approach

    Microsoft Academic Search

    Huiqing Zhai; Shaoshu Sha; Varun K. Shenoy; Sungyong Jung; Mingyu Lu; Kyoungwon Min; Sungchul Lee; Dong S. Ha

    2010-01-01

    In this paper, a compact and low-cost electronic circuit system is designed for time-reversal of ultra-wideband short impulses (with nanosecond and sub-nanosecond temporal durations). A frequency-domain approach is adopted to avoid high sampling rate in time. Specifically, the proposed system obtains the discrete spectra of input impulses first; then realizes time-reversal in frequency domain; and finally synthesizes the time-reversed impulses

  3. Evaluation of fused silica for DUV laser application by short-time diagnostics

    NASA Astrophysics Data System (ADS)

    Triebel, Wolfgang; Bark-Zollmann, Sylvia; Muehlig, Christian; Voitsch, Andreas; Coriand, Frank; Alkemper, Jochen

    2000-10-01

    Excimer laser pulses ((lambda) equals 193 nm, (lambda) equals 248 nm) induce transient and permanent defects in highly UV transparent optical glass for microlithography. Usually laser damage of fused silica is evaluated by time consuming and expensive marathon tests characterized by about 109 pulses at repetition rates of 400-1000 Hz and fluences of 0.5-10 mJ/cm2. Alternatively, short time tests using high laser energy densities have been developed to quickly evaluate influences of changes in the production technology. The following evaluation methods are used: Laser induced absorption at 193 nm measured by laser induced deflection (LID), Laser induced fluorescence at 650 nm (LIF) excited by 193 nm or 248 nm laser irradiation, H2 content measurement by means of a pulsed Raman spectroscopy at 248 nm laser excitation. Both, the LIF signal and the H2 concentration are measured locally resolved in a non-destructive way. The applied energy densities of the above methods vary from 1 mJ/cm2 to 600 mJ/cm2. The front face technique for investigating large diameter samples, e.g. mask blanks (6 inches and 9 inches), have been established.

  4. Temperature measurement by IR camera of heated device to high temperature during a short time

    NASA Astrophysics Data System (ADS)

    Sonneck-Museux, Nathanalle; Verg, Philippe; Judic, Jean-Pierre; Edard, Pierrick

    2015-04-01

    A device allowing heating a liquid to high temperatures during a very short time has been conceived in our laboratory. The goal of this survey is to find the suitable experimental configurations, so that tested material affected by the temperatures coved between 200 and 750C. This study is achieved to the Solar Furnace of the DGA in Odeillo. The cavity containing the liquid is a thermocouple sleeve (capillary) in Inconel 600. Its extremity is closed tightly by a removable steel plug permitting the tightness after replenishment. An electromagnet associated to a generator of delay permit to make fall the whole after the solar irradiation in liquid nitrogen in order to stop the reaction of "deterioration" of the tested product. According to capillary dimensions and to heating time, the temperature measurement using a pyrometer is not possible. A second possibility is using thermocouple, but it is not easy to join this captor on Inconel 600. Using by infrared camera allows observing the presence or the absence of inflammation during the solar irradiation and the sleeve fall too. The measures of temperatures by thermocouple show a lot of variability. The measures comparison with those by infrared camera shows a phenomenon of "heat well". Several score of tests to the solar furnace have been achieved in different experimental configurations. Nine experimental configurations have been validated, for variable flux of 100 to 500W/cm. The observation by infrared camera permitted to validate the conceived system and to verify the homogeneity of the sleeve heated.

  5. Investigation of astrophysical phenomena in short time scales with "Pi of the Sky" apparatus

    E-print Network

    Marcin Sokolowski

    2008-10-07

    In this thesis the data analysis designed by author for the "Pi of the Sky" experiment is presented. The data analysis consists of data reduction and specific algorithms for identification of short time scale astrophysical processes. The algorithms have been tested and their efficiency has been determined and described. The "Pi of the Sky" prototype is collecting data since June 2004 and algorithms could be intensively studied and improved during over 700 nights. A few events of confirmed astrophysical origin and above 100 events in 10s time scale of unknown nature have been discovered. During the data collection period 3 Gamma Ray Bursts (out of 231) occurred in the field of view of the telescope, but no optical counterpart has been found. The upper limits for brightness of the optical counterpart have been determined. The continuous monitoring of the sky and own trigger for optical flashes allowed to determine limits on the number of GRBs without corresponding gamma-ray detection. This allowed determining limits on the ratio of emission collimation in optical and gamma bands, which is R >= 4.4. The perspectives of the full "Pi of the Sky" system has been studied and number of positive detections has been estimated on the level of ~ 2.5 events per year.

  6. Short-time diffusion in concentrated bidisperse hard-sphere suspensions

    NASA Astrophysics Data System (ADS)

    Wang, Mu; Heinen, Marco; Brady, John F.

    2015-02-01

    Diffusion in bidisperse Brownian hard-sphere suspensions is studied by Stokesian Dynamics (SD) computer simulations and a semi-analytical theoretical scheme for colloidal short-time dynamics, based on Beenakker and Mazur's method [Physica A 120, 388-410 (1983); 126, 349-370 (1984)]. Two species of hard spheres are suspended in an overdamped viscous solvent that mediates the salient hydrodynamic interactions among all particles. In a comprehensive parameter scan that covers various packing fractions and suspension compositions, we employ numerically accurate SD simulations to compute the initial diffusive relaxation of density modulations at the Brownian time scale, quantified by the partial hydrodynamic functions. A revised version of Beenakker and Mazur's ??-scheme for monodisperse suspensions is found to exhibit surprisingly good accuracy, when simple rescaling laws are invoked in its application to mixtures. The so-modified ?? scheme predicts hydrodynamic functions in very good agreement with our SD simulation results, for all densities from the very dilute limit up to packing fractions as high as 40%.

  7. EUROGRAPHICS 2006 / D. W. Fellner and C. Hansen Short Papers Clothing the Masses: Real-Time Clothed Crowds With

    E-print Network

    O'Sullivan, Carol

    EUROGRAPHICS 2006 / D. W. Fellner and C. Hansen Short Papers Clothing the Masses: Real-Time Clothed of realistically clothed characters presents a difficult challenge in com- puter graphics, which is further methods have been used to animate the clothes of individuals in real-time crowds, which does not create

  8. Distributed Stochastic Power Control for Time-Varying Long-Term and Short-Term Fading Wireless Networks

    Microsoft Academic Search

    Mohammed M. Olama; Seddik M. Djouadi; Charalambos D. Charalambous; Samir Sahyoun

    2007-01-01

    In this paper, new time-varying wireless channel models that capture both the space and time variations of long- term and short-term fading wireless networks are developed. The proposed models are based on stochastic differential equations. These models are more realistic than the static ones usually encountered in the literature. Moreover, optimal power control algorithms based on the new models are

  9. Suborbital Intercept and Fragmentation of an Asteroid with Very Short Warning Time Scenario

    NASA Technical Reports Server (NTRS)

    Hupp, Ryan; DeWald, Spencer; Wie, Bong; Barbee, Brent W.

    2015-01-01

    Small near-Earth objects (NEOs) is approx. 50-150 m in size are far more numerous (hundreds of thousands to millions yet to be discovered) than larger NEOs. Small NEOs, which are mostly asteroids rather than comets, are very faint in the night sky due to their small sizes, and are, therefore, difficult to discover far in advance of Earth impact. Furthermore, even small NEOs are capable of creating explosions with energies on the order of tens or hundreds of megatons (Mt). We are, therefore, motivated to prepare to respond effectively to short warning time, small NEO impact scenarios. In this paper we explore the lower bound on actionable warning time by investigating the performance of notional upgraded Intercontinental Ballistic Missiles (ICBMs) to carry Nuclear Explosive Device (NED) payloads to intercept and disrupt a hypothetical incoming NEO at high altitudes (generally at least 2500 km above Earth). We conduct this investigation by developing optimal NEO intercept trajectories for a range of cases and comparing their performances. Our results show that suborbital NEO intercepts using Minuteman III or SM-3 IIA launch vehicles could achieve NEO intercept a few minutes prior to when the NEO would strike Earth. We also find that more powerful versions of the launch vehicles (e.g., total deltaV is approx. 9.5-11 km/s) could intercept incoming NEOs several hours prior to when the NEO would strike Earth, if launched at least several days prior to the time of intercept. Finally, we discuss a number of limiting factors and practicalities that affect whether the notional systems we describe could become feasible.

  10. The Fully Polynomial-Time Approximation Scheme for Feasibility Analysis in Static-Priority Systems with Arbitrary Relative Deadlines Revisited

    E-print Network

    Paris-Sud XI, Universit de

    for computing worst-case response times for this task model. Fisher and Baruah proposed in 2005 an approxi- mate for computing worst-case re- sponse times for this task model. Fisher and Baruah pro- posed in 2005

  11. A Real-Time MODIS Vegetation Composite for Land Surface Models and Short-Term Forecasting

    NASA Technical Reports Server (NTRS)

    Case, Jonathan L.; LaFontaine, Frank J.; Kumar, Sujay V.; Jedlovec, Gary J.

    2011-01-01

    The NASA Short-term Prediction Research and Transition (SPoRT) Center is producing real-time, 1- km resolution Normalized Difference Vegetation Index (NDVI) gridded composites over a Continental U.S. domain. These composites are updated daily based on swath data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the polar orbiting NASA Aqua and Terra satellites, with a product time lag of about one day. A simple time-weighting algorithm is applied to the NDVI swath data that queries the previous 20 days of data to ensure a continuous grid of data populated at all pixels. The daily composites exhibited good continuity both spatially and temporally during June and July 2010. The composites also nicely depicted high greenness anomalies that resulted from significant rainfall over southwestern Texas, Mexico, and New Mexico during July due to early-season tropical cyclone activity. The SPoRT Center is in the process of computing greenness vegetation fraction (GVF) composites from the MODIS NDVI data at the same spatial and temporal resolution for use in the NASA Land Information System (LIS). The new daily GVF dataset would replace the monthly climatological GVF database (based on Advanced Very High Resolution Radiometer [AVHRR] observations from 1992-93) currently available to the Noah land surface model (LSM) in both LIS and the public version of the Weather Research and Forecasting (WRF) model. The much higher spatial resolution (1 km versus 0.15 degree) and daily updates based on real-time satellite observations have the capability to greatly improve the simulation of the surface energy budget in the Noah LSM within LIS and WRF. Once code is developed in LIS to incorporate the daily updated GVFs, the SPoRT Center will conduct simulation sensitivity experiments to quantify the impacts and improvements realized by the MODIS real-time GVF data. This presentation will describe the methodology used to develop the 1-km MODIS NDVI composites and show sample output from summer 2010, compare the MODIS GVF data to the AVHRR monthly climatology, and illustrate the sensitivity of the Noah LSM within LIS and/or the coupled LIS/WRF system to the new MODIS GVF dataset.

  12. Application of MOSFET detectors for dosimetry in small animal radiography using short exposure times.

    PubMed

    De Lin, Ming; Toncheva, Greta; Nguyen, Giao; Kim, Sangroh; Anderson-Evans, Colin; Johnson, G Allan; Yoshizumi, Terry T

    2008-08-01

    Digital subtraction angiography (DSA) X-ray imaging for small animals can be used for functional phenotyping given its ability to capture rapid physiological changes at high spatial and temporal resolution. The higher temporal and spatial requirements for small-animal imaging drive the need for short, high-flux X-ray pulses. However, high doses of ionizing radiation can affect the physiology. The purpose of this study was to verify and apply metal oxide semiconductor field effect transistor (MOSFET) technology to dosimetry for small-animal diagnostic imaging. A tungsten anode X-ray source was used to expose a tissue-equivalent mouse phantom. Dose measurements were made on the phantom surface and interior. The MOSFETs were verified with thermoluminescence dosimeters (TLDs). Bland-Altman analysis showed that the MOSFET results agreed with the TLD results (bias, 0.0625). Using typical small animal DSA scan parameters, the dose ranged from 0.7 to 2.2 cGy. Application of the MOSFETs in the small animal environment provided two main benefits: (1) the availability of results in near real-time instead of the hours needed for TLD processes and (2) the ability to support multiple exposures with different X-ray techniques (various of kVp, mA and ms) using the same MOSFET. This MOSFET technology has proven to be a fast, reliable small animal dosimetry method for DSA imaging and is a good system for dose monitoring for serial and gene expression studies. PMID:18666818

  13. Application of MOSFET Detectors for Dosimetry in Small Animal Radiography Using Short Exposure Times

    PubMed Central

    De Lin, Ming; Toncheva, Greta; Nguyen, Giao; Kim, Sangroh; Anderson-Evans, Colin; Johnson, G. Allan; Yoshizumi, Terry T.

    2008-01-01

    Digital subtraction angiography (DSA) X-ray imaging for small animals can be used for functional phenotyping given its ability to capture rapid physiological changes at high spatial and temporal resolution. The higher temporal and spatial requirements for small-animal imaging drive the need for short, high-flux X-ray pulses. However, high doses of ionizing radiation can affect the physiology. The purpose of this study was to verify and apply metal oxide semiconductor field effect transistor (MOSFET) technology to dosimetry for small-animal diagnostic imaging. A tungsten anode X-ray source was used to expose a tissue-equivalent mouse phantom. Dose measurements were made on the phantom surface and interior. The MOSFETs were verified with thermoluminescence dosimeters (TLDs). Bland-Altman analysis showed that the MOSFET results agreed with the TLD results (bias, 0.0625). Using typical small animal DSA scan parameters, the dose ranged from 0.7 to 2.2 cGy. Application of the MOSFETs in the small animal environment provided two main benefits: (1) the availability of results in near real-time instead of the hours needed for TLD processes and (2) the ability to support multiple exposures with different X-ray techniques (various of kVp, mA and ms) using the same MOSFET. This MOSFET technology has proven to be a fast, reliable small animal dosimetry method for DSA imaging and is a good system for dose monitoring for serial and gene expression studies. PMID:18666818

  14. Short-time rheology and diffusion in suspensions of Yukawa-type colloidal particles

    NASA Astrophysics Data System (ADS)

    Heinen, Marco; Banchio, Adolfo J.; Ngele, Gerhard

    2011-10-01

    A comprehensive study is presented on the short-time dynamics in suspensions of charged colloidal spheres. The explored parameter space covers the major part of the fluid-state regime, with colloid concentrations extending up to the freezing transition. The particles are assumed to interact directly by a hard-core plus screened Coulomb potential, and indirectly by solvent-mediated hydrodynamic interactions. By comparison with accurate accelerated Stokesian Dynamics (ASD) simulations of the hydrodynamic function H(q), and the high-frequency viscosity ??, we investigate the accuracy of two fast and easy-to-implement analytical schemes. The first scheme, referred to as the pairwise additive (PA) scheme, uses exact two-body hydrodynamic mobility tensors. It is in good agreement with the ASD simulations of H(q) and ??, for smaller volume fractions up to about 10% and 20%, respectively. The second scheme is a hybrid method combining the virtues of the ?? scheme by Beenakker and Mazur with those of the PA scheme. It leads to predictions in good agreement with the simulation data, for all considered concentrations, combining thus precision with computational efficiency. The hybrid method is used to test the accuracy of a generalized Stokes-Einstein (GSE) relation proposed by Kholodenko and Douglas, showing its severe violation in low salinity systems. For hard spheres, however, this GSE relation applies decently well.

  15. SHORT CONTACT TIME DIRECT COAL LIQUEFACTION USING A NOVEL BATCH REACTOR

    SciTech Connect

    Michael T. Klein; William H. Calkins

    1997-10-29

    The overall goal of this research is to develop an understanding of the Direct Coal Liquefaction process at the molecular level. Many approaches have been used to study this process including kinetic studies, study of the liquefaction products, study of the effect of reaction variables, such as temperature, solvent type and composition, the changing nature and composition of the coal during liquefaction, and the distribution in the liquefaction products of the hydrogen consumed. While all these studies have contributed to our growing knowledge of the liquefaction process, an adequate understanding of direct liquefaction still eludes us. This is due to many reasons including: the complexity and variable nature of coal itself and the many different chemical reactions which are occurring simultaneously during direct coal liquefaction. We believe that a study of the liquefaction process at the very early stages will avoid the complexities of secondary reactions associated with free radical high temperature processes that are clearly involved in direct coal liquefaction. This prompted us to devise a reactor system which avoids long heat up and cool-down times associated with previous kinetic studies, and allows kinetic measurements even at as short as the first few seconds of the liquefaction reaction.

  16. Zipf's Law in Short-Time Timbral Codings of Speech, Music, and Environmental Sound Signals

    PubMed Central

    Haro, Martn; Serr, Joan; Herrera, Perfecto; Corral, lvaro

    2012-01-01

    Timbre is a key perceptual feature that allows discrimination between different sounds. Timbral sensations are highly dependent on the temporal evolution of the power spectrum of an audio signal. In order to quantitatively characterize such sensations, the shape of the power spectrum has to be encoded in a way that preserves certain physical and perceptual properties. Therefore, it is common practice to encode short-time power spectra using psychoacoustical frequency scales. In this paper, we study and characterize the statistical properties of such encodings, here called timbral code-words. In particular, we report on rank-frequency distributions of timbral code-words extracted from 740 hours of audio coming from disparate sources such as speech, music, and environmental sounds. Analogously to text corpora, we find a heavy-tailed Zipfian distribution with exponent close to one. Importantly, this distribution is found independently of different encoding decisions and regardless of the audio source. Further analysis on the intrinsic characteristics of most and least frequent code-words reveals that the most frequent code-words tend to have a more homogeneous structure. We also find that speech and music databases have specific, distinctive code-words while, in the case of the environmental sounds, this database-specific code-words are not present. Finally, we find that a Yule-Simon process with memory provides a reasonable quantitative approximation for our data, suggesting the existence of a common simple generative mechanism for all considered sound sources. PMID:22479497

  17. Comparison of a short-time speech-based intelligibility metric to the speech transmission index and intelligibility data.

    PubMed

    Payton, Karen L; Shrestha, Mona

    2013-11-01

    Several algorithms have been shown to generate a metric corresponding to the Speech Transmission Index (STI) using speech as a probe stimulus [e.g., Goldsworthy and Greenberg, J. Acoust. Soc. Am. 116, 3679-3689 (2004)]. The time-domain approaches work well on long speech segments and have the added potential to be used for short-time analysis. This study investigates the performance of the Envelope Regression (ER) time-domain STI method as a function of window length, in acoustically degraded environments with multiple talkers and speaking styles. The ER method is compared with a short-time Theoretical STI, derived from octave-band signal-to-noise ratios and reverberation times. For windows as short as 0.3?s, the ER method tracks short-time Theoretical STI changes in stationary speech-shaped noise, fluctuating restaurant babble and stationary noise plus reverberation. The metric is also compared to intelligibility scores on conversational speech and speech articulated clearly but at normal speaking rates (Clear/Norm) in stationary noise. Correlation between the metric and intelligibility scores is high and, consistent with the subject scores, the metrics are higher for Clear/Norm speech than for conversational speech and higher for the first word in a sentence than for the last word. PMID:24180791

  18. New General Continuous-Time State?Task Network Formulation for Short-Term Scheduling of Multipurpose Batch Plants

    Microsoft Academic Search

    Christos T. Maravelias; Ignacio E. Grossmann

    2003-01-01

    A new continuous time MILP model for the short-term scheduling of multipurpose batch plants is presented. The proposed model relies on the State Task Network (STN) and addresses the general problem of batch scheduling, accounting for resource (utility) constraints, variable batch sizes and processing times, various storage policies (UIS\\/FIS\\/NIS\\/ZW), batch mixing\\/splitting, and sequence- dependent changeover times. The key features of

  19. Short echo time proton spectroscopy of the brain in healthy volunteers using an insert gradient head coil

    Microsoft Academic Search

    Peter Gideon; Else Rubk Danielsen; Monika Schneider; Ole Henriksen

    1995-01-01

    An insert gradient head coil with built-in X, Y, and Z gradients was used for localized proton spectroscopy in the brain of healthy volunteers, using short echo time stimulated echo acquisition mode (STEAM) sequences. Volume of interest size was 3.4 ml, repetition time was 6.0 s, and echo times were 10 and 20 ms, respectively. Good quality proton spectra with

  20. Effects of lateral velocity heterogeneity under the Nevada Test Site on short-period P wave amplitudes and travel times

    Microsoft Academic Search

    Christopher S. Lynnes; Thorne Lay

    1990-01-01

    Short-period teleseismicP waves from the Nevada Test Site (NTS) show systematic variations in amplitudes and travel times, with low amplitudes corresponding to fast travel times, suggesting elastic focussing-defocussing effects. Also, the azimuthal amplitude and travel time patterns for events at the Pahute Mesa subsite are systematically different from those at the Yucca Flat subsite, indicating the presence of a near-source

  1. Short contact time direct coal liquefaction using a novel batch reactor. Quarterly report, May 15, 1995--September 15, 1995

    SciTech Connect

    Klein, M.T.; Calkins, W.H.; Huang, He

    1995-10-05

    The objective of this research is to optimize the design and operation of the bench scale batch reactor for coal liquefaction at short contact times (0.01 to 10 minutes or longer). Additional objectives are to study the kinetics of direct coal liquefaction, particularly at short reaction times, and to investigate the role of the organic oxygen components of coal and their reaction pathways during liquefaction. This quarterly report covers the status of progress toward these objectives. 3 refs., 14 figs., 2 tabs.

  2. Response Time Measurements in Short-Wave Infrared HgCdTe e-APDs

    NASA Astrophysics Data System (ADS)

    Rothman, Johan; Foubert, Kevin; Lasfargues, Gilles; Largeron, Christophe

    2014-08-01

    The impulse response time has been measured as a function of reverse bias, gain, and temperature in backside-illuminated short-wave infrared HgCdTe avalanche photodiodes (APDs) with variable junction geometry. The APD geometry was altered using HgCdTe substrates of variable thickness and by variation of device fabrication parameters. This approach allowed study of the drift-diffusion dynamics of the electrons before entering the junction and the electron and hole dynamics during the junction transition in APDs with different carrier collection distances and junction widths. The response time was typically limited by a double exponential decay, which is attributed to contributions from the impedance mismatch between the interconnection circuit and the 50-? radiofrequency probe, and a delayed diffusion response from carriers generated far from the junction. These contributions limited the maximum bandwidth of the diodes to about 600 MHz, independently of gain and temperature. The hot carrier velocities are estimated by fitting the measured response with numerical calculations, taking into account contributions from a direct drift-multiplication response and a delayed diffusion response. This analysis shows that the hot carrier dynamics is close to independent of temperature and that the electron drift velocity saturates at the gain onset to a value of 1 107 cm/s, decreasing upon a further increase of the electric field E to a value of about 3 106 cm/s at E = 100 kV/cm. The hole velocity shows a slow variation from 3 106 cm/s at low electric fields to 1.5 106 cm/s at high electric fields.

  3. The rate, luminosity function and time delay of non-Collapsar short GRBs

    NASA Astrophysics Data System (ADS)

    Wanderman, David; Piran, Tsvi

    2015-04-01

    We estimate the rate and the luminosity function of short (hard) Gamma-Ray Bursts (sGRBs) that are non-Collapsars, using the peak fluxes and redshifts of BATSE, Swift and Fermi GRBs. Following Bromberg et al., we select a sub-sample of Swift bursts which are most likely non-Collapsars. We find that these sGRBs are delayed relative to the global star formation rate (SFR) with a typical delay time of a 3-4 Gyr (depending on the SFR model). However, if two or three sGRB at high redshifts have been missed because of selection effects, a distribution of delay times of ? 1/t would be also compatible. The current event rate of these non-Collapsar sGRBs with Liso > 5 1049 erg s-1 is 4.1_{-1.9}^{+2.3} Gpc^{-3} yr^{-1}. The rate was significantly larger around z 1 and it declines since that time. The luminosity function we find is a broken power law with a break at 2.0_{-0.4}^{+1.4} 10^{52} erg s^{-1} and power-law indices 0.95_{-0.1 2}^{+0.12} and 2.0_{-0.8}^{+1.0}. When considering the whole Swift sGRB sample we find that it is composed of two populations: one group (?60-80 per cent of Swift sGRBs) with the above rate and time delay and a second group (?20-40 per cent of Swift sGRBs) of potential `impostors' that follow the SFR with no delay. These two populations are in very good agreement with the division of sGRBs to non-Collapsars and Collapsars suggested recently by Bromberg et al. If non-Collapsar sGRBs arise from neutron star merger this rate suggest a detection rate of 3-100 yr-1 by a future gravitational wave detectors (e.g. Advanced Ligo/Virgo with detection horizon on 300 Mpc), and a co-detection with Fermi (Swift ) rate of 0.1-1 yr-1 (0.02-0.14 yr-1). We estimate that about 4 10^5 (f_b^{-1}/30) mergers took place in the Milky Way. If 0.025M? were ejected in each event this would have been sufficient to produce all the heavy r-process material in the Galaxy.

  4. Time and frequency domain responses of the mechanomyogram and electromyogram during isometric ramp contractions: A comparison of the short-time Fourier and continuous wavelet transforms

    Microsoft Academic Search

    Eric D. Ryan; Joel T. Cramer; Alison D. Egan; Michael J. Hartman; Trent J. Herda

    2008-01-01

    The purposes of this study were to examine the mechanomyographic (MMG) and electromyographic (EMG) time and frequency domain responses of the vastus lateralis (VL) and rectus femoris (RF) muscles during isometric ramp contractions and compare the timefrequency of the MMG and EMG signals generated by the short-time Fourier transform (STFT) and continuous wavelet transform (CWT). Nineteen healthy subjects (meanSD age=244

  5. A coordinated approach for real-time short term hydro scheduling

    SciTech Connect

    Tufegdzic, N. [Hydro Electric Commission, Hobart (Australia)] [Hydro Electric Commission, Hobart (Australia); Frowd, R.J. [Landis and Gyr Energy Management, San Jose, CA (United States)] [Landis and Gyr Energy Management, San Jose, CA (United States); Stadlin, W.O. [Macro Corp., Horsham, PA (United States)] [Macro Corp., Horsham, PA (United States)

    1996-11-01

    The paper describes a coordinated approach to short-term hydro scheduling and dispatch that has been developed as a part of the Tasmanian Hydro Electric Commission`s (HEC) new Energy Management System (EMS), which is being delivered by Landis and Gyr Energy Management. Tasmania`s hydro generation system consists of 40 reservoirs in six river catchments. The daily water release for each plant is scheduled using the HEC`s mid-term operation policy. The Hydro Scheduling and Commitment (HSC) function schedules the hydro units on a half hourly basis so that the allocated water release maximizes the energy production. This maximization of energy production is achieved by maximizing the head and this ensures that operation is always as close as possible to maximum efficiency. Mixed Integer Linear Programming is used with a detailed model of the interconnected hydro system to determine the half-hourly operation schedule. The Hydro Economic Dispatch (HED) function is used to implement the schedules produced by HSC in the real-time operation. The HED also uses a detailed model of the hydro system with a Linear Programming algorithm to ensure that each unit operates as close as possible to its head-dependent theoretical maximum efficiency point while meeting the desired storage levels specified by the HSC solution. HSC and HED have been tested against a number of operational scenarios and when it is fully integrated within the new EMS it is expected to yield annual stored energy savings up to 0.5% through more efficient hydro-electric system operation. It is expected to also provide additional savings by fostering improvements to the mid-term operating plan.

  6. 1: Know your story. What is the main information you want to tell? In the short time someone stands in

    E-print Network

    New Hampshire, University of

    1: Know your story. What is the main information you want to tell? In the short time someone stands allowed by conference) Contact Information: address, email, phone, website (url) Title, 3 authors & 2 and the poster should include only what supports that story. Knowing the story you want to tell helps you edit

  7. THERMAL INACTIVATION OF FOOT-AND-MOUTH DISEASE VIRUS IN MILK USING HIGH-TEMPERATURE SHORT TIME PASTEURIZATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous studies of laboratory simulation of high temperature short time pasteurization (HTST) to eliminate foot-and-mouth disease virus (FMDV) in milk have shown that the virus is not completely inactivated at the legal pasteurization minimum (71.7 deg C/15 sec) but is inactivated in flow apparatus...

  8. Relationship between Measures of Working Memory Capacity and the Time Course of Short-Term Memory Retrieval and Interference Resolution

    ERIC Educational Resources Information Center

    Oztekin, Ilke; McElree, Brian

    2010-01-01

    The response-signal speed-accuracy trade-off (SAT) procedure was used to investigate the relationship between measures of working memory capacity and the time course of short-term item recognition. High- and low-span participants studied sequentially presented 6-item lists, immediately followed by a recognition probe. Analyses of composite list

  9. Extremely short external cavity lasers: Direct semiconductor laser readout modeling by using finite difference time domain calculations

    Microsoft Academic Search

    Janne K. Aikio; Kari J. Kataja; Dennis G. Howe

    2001-01-01

    In this paper we describe how finite difference time domain (FDTD) calculations can be used in the modeling of extremely short external cavity (ESEC) lasers. We concentrate on the applications of ESEC lasers in modern optical data storage systems: we study the operation of direct semiconductor laser read\\/write heads that utilize either a conventional edge emitting laser or very small

  10. Extremely short external-cavity lasers: direct semiconductor laser readout modeling by using finite difference time domain calculations

    Microsoft Academic Search

    Janne K. Aikio; Kari J. Kataja; Dennis G. Howe

    2001-01-01

    In this paper we describe how finite difference time domain (FDTD) calculations can be used in the modeling of extremely short external cavity (ESEC) lasers. We concentrate on the applications of ESEC lasers in modern optical data storage systems: we study the operation of direct semiconductor laser read\\/write heads that utilize either a conventional edge emitting laser or very small

  11. Short-time asymptotics of a rigorous path integral for N = 1 supersymmetric quantum mechanics on a Riemannian manifold

    SciTech Connect

    Fine, Dana S., E-mail: dfine@umassd.edu [Mathematics Department, University of Massachusetts Dartmouth, North Dartmouth, Massachusetts 02747 (United States); Sawin, Stephen, E-mail: ssawin@fairfield.edu [Mathematics Department, Fairfield University, Fairfield, Connecticut 06824 (United States)

    2014-06-15

    Following Feynman's prescription for constructing a path integral representation of the propagator of a quantum theory, a short-time approximation to the propagator for imaginary-time, N = 1 supersymmetric quantum mechanics on a compact, even-dimensional Riemannian manifold is constructed. The path integral is interpreted as the limit of products, determined by a partition of a finite time interval, of this approximate propagator. The limit under refinements of the partition is shown to converge uniformly to the heat kernel for the Laplace-de Rham operator on forms. A version of the steepest descent approximation to the path integral is obtained, and shown to give the expected short-time behavior of the supertrace of the heat kernel.

  12. A new continuous-time state task network formulation for short term scheduling of multipurpose batch plants

    Microsoft Academic Search

    Christos T. Maravelias; Ignacio E. Grossmann

    2003-01-01

    A new continuous-time MILP model for the short-term scheduling of multipurpose batch plants is presented. The proposed model relies on the idea of the State Task Network (STN) and addresses the general problem of batch scheduling, accounting for resources other than equipment (utilities), variable batch sizes and processing times, various storage policies (UIS\\/FIS\\/NIS\\/ZW) and batch splitting\\/mixing. Compared to other general

  13. Personality Over Time: Methodological Approaches to the Study of Short-Term and Long-Term Development and Change

    Microsoft Academic Search

    Jeremy C. Biesanz; Stephen G. West; Oi-Man Kwok

    2003-01-01

    Although theories of personality emphasize the integra- tive, enduring, and dynamic nature of personality, the current modal research design in personality ignores the dimension of time. We consider a variety of recent methods of longitudinal data analysis to examine both short-term and long-term development and change in personality, including mean-level analyses both across and within individuals across time, variance structures

  14. Revisiting the question: Does high-latitude solar activity lead low-latitude solar activity in time phase?

    SciTech Connect

    Kong, D. F.; Qu, Z. N. [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Guo, Q. L., E-mail: kdf@ynao.ac.cn [College of Mathematics Physics and Information Engineering, Jiaxing University, Jiaxing 314001 (China)

    2014-05-01

    Cross-correlation analysis and wavelet transform methods are used to investigate whether high-latitude solar activity leads low-latitude solar activity in time phase or not, using the data of the Carte Synoptique solar filaments archive from 1919 March to 1989 December. From the cross-correlation analysis, high-latitude solar filaments have a time lead of 12 Carrington solar rotations with respect to low-latitude ones. Both the cross-wavelet transform and wavelet coherence indicate that high-latitude solar filaments lead low-latitude ones in time phase. Furthermore, low-latitude solar activity is better correlated with high-latitude solar activity of the previous cycle than with that of the following cycle, which is statistically significant. Thus, the present study confirms that high-latitude solar activity in the polar regions is indeed better correlated with the low-latitude solar activity of the following cycle than with that of the previous cycle, namely, leading in time phase.

  15. Power to detect trend in short-term time series of bird abundance

    USGS Publications Warehouse

    Thogmartin, W.E.; Gray, B.R.; Gallagher, M.; Young, N.; Rohweder, J.J.; Knutson, M.G.

    2007-01-01

    Avian point counts for population monitoring are often collected over a short timespan (e.g., 3-5 years). We examined whether power was adequate (power ???0.80) in short-duration studies to warrant the calculation of trend estimates. We modeled power to detect trends in abundance indices of eight bird species occurring across three floodplain habitats (wet prairie, early successional forest, and mature forest) as a function of trend magnitude, sample size, and species-specific sampling and among-year variance components. Point counts (5 min) were collected from 365 locations distributed among 10 study sites along the lower Missouri River; counts were collected over the period 2002 to 2004. For all study species, power appeared adequate to detect trends in studies of short duration (three years) at a single site when exponential declines were relatively large in magnitude (more than -5% year-1) and the sample of point counts per year was ???30. Efforts to monitor avian trends with point counts in small managed lands (i.e., refuges and parks) should recognize this sample size restriction by including point counts from offsite locations as a means of obtaining sufficient numbers of samples per strata. Trends of less than -5% year-1 are not likely to be consistently detected for most species over the short term, but short-term monitoring may still be useful as the basis for comparisons with future surveys. ?? The Cooper Ornithological Society 2007.

  16. Parallel Data Mining Revisited. Better, Not Faster

    E-print Network

    Berthold, Michael R.

    into two main themes: "big data" type analyses, where the goal is still the efficient mining of insightsParallel Data Mining Revisited. Better, Not Faster Zaenal Akbar, Violeta N. Ivanova, and Michael R is to tune data mining algorithms to produce better results in the same time rather than producing similar

  17. Revisiting the Regenerative Possibilities of Ortiz

    ERIC Educational Resources Information Center

    Duques, Matthew

    2004-01-01

    The author of this article revisits Simon Ortiz's poem, "From Sand Creek," in which the latter can in so few words convey both the horrific tragedy of conquest and colonization, while at the same time find a space for possibility, a means for recovery that is never about forgetting but always occurs as a kind of recuperative remembering. Ortiz

  18. Optical design of the short pulse x-ray imaging and microscopy time-angle correlated diffraction beamline at the Advanced Photon Source

    E-print Network

    Evans, Paul G.

    Optical design of the short pulse x-ray imaging and microscopy time-angle correlated diffraction://rsi.aip.org/about/rights_and_permissions #12;REVIEW OF SCIENTIFIC INSTRUMENTS 84, 053103 (2013) Optical design of the short pulse x-ray imaging April 2013; published online 10 May 2013) The short pulse x-ray imaging and microscopy beamline is one

  19. 42 CFR 488.30 - Revisit user fee for revisit surveys.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... false Revisit user fee for revisit surveys. 488.30 Section 488.30 Public...CONTINUED) STANDARDS AND CERTIFICATION SURVEY, CERTIFICATION, AND ENFORCEMENT PROCEDURES...488.30 Revisit user fee for revisit surveys. (a) Definitions. As used...

  20. 42 CFR 488.30 - Revisit user fee for revisit surveys.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... false Revisit user fee for revisit surveys. 488.30 Section 488.30 Public...CONTINUED) STANDARDS AND CERTIFICATION SURVEY, CERTIFICATION, AND ENFORCEMENT PROCEDURES...488.30 Revisit user fee for revisit surveys. (a) Definitions. As used...

  1. 42 CFR 488.30 - Revisit user fee for revisit surveys.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... false Revisit user fee for revisit surveys. 488.30 Section 488.30 Public...CONTINUED) STANDARDS AND CERTIFICATION SURVEY, CERTIFICATION, AND ENFORCEMENT PROCEDURES...488.30 Revisit user fee for revisit surveys. (a) Definitions. As used...

  2. Cultural techniques for altering the flowering time and double-cropping short-day varieties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    July-plugged transplants of short-day cv. Strawberry Festival (Fragaria x ananassa), flowered in October and November even though they were grown under long photoperiods and warm temperatures (greater than 21 degrees C) in July and August. These unexpected results were attributed to a high plant de...

  3. Short Time Rated And Protected High Voltage Ac Testing Of Generator Stators Using Parallel Resonant Circuits

    Microsoft Academic Search

    Wade Enright; Pat Bodger

    Power station generators require short duration HV ac testing of their insulation as part of their acceptance before being put into service. Depending on the value of the capacitance of the insulation, the rating of the test power supply can be large. One method of reducing this supply requirement is to compensate the capacitance with inductance. The paper describes a

  4. Cognitive Abilities Explaining Age-Related Changes in Time Perception of Short and Long Durations

    ERIC Educational Resources Information Center

    Zelanti, Pierre S.; Droit-Volet, Sylvie

    2011-01-01

    The current study investigated how the development of cognitive abilities explains the age-related changes in temporal judgment over short and long duration ranges from 0.5 to 30 s. Children (5- and 9-year-olds) as well as adults were given a temporal bisection task with four different duration ranges: a duration range shorter than 1 s, two

  5. On the validity of the Boltzmann equation for short range potentials

    E-print Network

    Mario Pulvirenti; Chiara Saffirio; Sergio Simonella

    2014-01-04

    We consider a classical system of point particles interacting by means of a short range potential. We prove that, in the low--density (Boltzmann--Grad) limit, the system behaves, for short times, as predicted by the associated Boltzmann equation. This is a revisitation and an extension of the thesis of King (unpublished), appeared after the well known result of Lanford for hard spheres, and of a recent paper by Gallagher et al (arXiv: 1208.5753v1). Our analysis applies to any stable and smooth potential. In the case of repulsive potentials (with no attractive parts), we estimate explicitly the rate of convergence.

  6. On the validity of the Boltzmann equation for short range potentials

    NASA Astrophysics Data System (ADS)

    Pulvirenti, M.; Saffirio, C.; Simonella, S.

    2014-02-01

    We consider a classical system of point particles interacting by means of a short range potential. We prove that, in the low-density (Boltzmann-Grad) limit, the system behaves, for short times, as predicted by the associated Boltzmann equation. This is a revisitation and an extension of the thesis of King [9] (that appeared after the well-known result of Lanford [10] for hard spheres) and of a recent paper by Gallagher et al. [5]. Our analysis applies to any stable and smooth potential. In the case of repulsive potentials (with no attractive parts), we estimate explicitly the rate of convergence.

  7. Revisiting the impact of part-time work on adolescent adjustment: distinguishing between selection and socialization using propensity score matching.

    PubMed

    Monahan, Kathryn C; Lee, Joanna M; Steinberg, Laurence

    2011-01-01

    The impact of part-time employment on adolescent functioning remains unclear because most studies fail to adequately control for differential selection into the workplace. The present study reanalyzes data from L. Steinberg, S. Fegley, and S. M. Dornbusch (1993) using multiple imputation, which minimizes bias in effect size estimation, and 2 types of propensity score matching, to account for selection effects. In this sample (N = 1,792; Grades 10-11, M = 16.26), youth who begin working more than 20 hr per week evince declines in school engagement and increases in substance use and delinquency compared with youth who remain unemployed. Conversely, working 20 hr or less a week has negligible effects, positive or negative, on academic, psychological, or behavioral outcomes. PMID:21291431

  8. CCD time-series photometry of the globular cluster NGC 5053: RR Lyrae, Blue Stragglers and SX Phoenicis stars revisited

    NASA Astrophysics Data System (ADS)

    Arellano Ferro, A.; Giridhar, Sunetra; Bramich, D. M.

    2010-02-01

    We report the results of CCD V, r and I time-series photometry of the globular cluster NGC 5053. New times of maximum light are given for the eight known RR Lyrae stars in the field of our images, and their periods are revised. Their V light curves were Fourier decomposed to estimate their physical parameters. A discussion on the accuracy of the Fourier-based iron abundances, temperatures, masses and radii is given. New periods are found for the five known SX Phe stars, and a critical discussion of their secular period changes is offered. The mean iron abundance for the RR Lyrae stars is found to be [Fe/H] ~ -1.97 +/- 0.16 and lower values are not supported by the present analysis. The absolute magnitude calibrations of the RR Lyrae stars yield an average true distance modulus of 16.12 +/- 0.04 or a distance of 16.7 +/- 0.3 kpc. Comparison of the observational colour magnitude diagram (CMD) with theoretical isochrones indicates an age of 12.5 +/- 2.0 Gyr for the cluster. A careful identification of all reported blue stragglers (BS) and their V, I magnitudes leads to the conclusion that BS12, BS22, BS23 and BS24 are not BS. On the other hand, three new BS are reported. Variability was found in seven BS, very likely of the SX Phe type in five of them, and in one red giant star. The new SX Phe stars follow established Period-Luminosity relationships and indicate a distance in agreement with the distance from the RR Lyrae stars. Based on observations collected at the Indian Astrophysical Observatory, Hanle, India. E-mail: armando@astroscu.unam.mx (AAF); giridhar@iiap.res.in (SG); dan.bramich@hotmail.co.uk (DMB)

  9. Modelling the water balance of a precise weighable lysimeter for short time scales

    NASA Astrophysics Data System (ADS)

    Fank, Johann; Klammler, Gernot; Rock, Gerhard

    2015-04-01

    Precise knowledge of the water fluxes between the atmosphere and the soil-plant system and the percolation to the groundwater system is of great importance for understanding and modeling water, solute and energy transfer in the atmosphere-plant-soil-groundwater system. Weighable lysimeters yield the most precise and realistic measures for the change of stored water volume (?S), Precipitation (P) which can be rain, irrigation, snow and dewfall and evapotranspiration (ET) as the sum of soil evaporation, evaporation of intercepted water and transpiration. They avoid systematic errors of standard gauges and class-A pans. Lysimeters with controlled suction at the lower boundary allow estimation of capillary rise (C) and leachate (L) on short time scales. Precise weighable large scale (surface >= 1 m2) monolithic lysimeters avoiding oasis effects allow to solve the water balance equation (P - ET - L + C ?S = 0) for a 3D-section of a natural atmosphere-plant-soil-system for a certain time period. Precision and accuracy of the lysimeter measurements depend not only on the precision of the weighing device but also on external conditions, which cannot be controlled or turned off. To separate the noise in measured data sets from signals the adaptive window and adaptive threshold (AWAT) filter (Peters et al., 2014) is used. The data set for the years 2010 and 2011 from the HYDRO-lysimeter (surface = 1 m2, depth = 1 m) in Wagna, Austria (Klammler and Fank, 2014) with a resolution of 0,01 mm for the lysimeter scale and of 0,001 mm for the leachate tank scale is used to evaluate the water balance. The mass of the lysimeter and the mass of the leachate tank is measured every two seconds. The measurements are stored as one minute arithmetic means. Based on calculations in a calibration period from January to May 2010 with different widths of moving window the wmax - Parameter for the AWAT filter was set to 41 minutes. A time series for the system mass ('upper boundary') of the lysimeter has been calculated by adding lysimeter mass and the leachate tank mass for every minute. Based on the resolution of the scales and an evaluation of noise in periods without precipitation and evaporation a dmin-value of 0.002 to filter the leachate tank measurements and a dmin-value of 0.012 was used to filter the lysimeter weight data and the upper boundary data. A mandatory requirement for the quantification of P or ET from lysimeter measurements is that in a reasonably small time interval, either P or ET is negligible. With this assumption, every increase in upper boundary data is interpreted as P. Every increase of seepage mass is interpreted as L, every decrease as C. ?S is evaluated from filtered lysimeter mass. ET is calculated using the water balance equation. The evaluation results are given as water balance components time series on a minute scale. P measured with the lysimeter for the two years 2010 and 2011 is 105 % of precipitation measured with a standard tipping bucket gauge 100 m beside the lysimeter. While P during the summer season (April to September) is very close to standard precipitation measurement, P during the winter season is more than 120 % of tipping bucket precipitation. Meissner et al. (2007) showed that P includes precipitation of dewfall and rime. A detailed evaluation of the HYDRO-Lysimeter in Wagna showed, that precipitation in the night and not recognized with the standard tipping bucket (interpreted as dew or rime) is about 1 % of P, the highest monthly sums (> 1 mm) are recognized from August to November. Klammler, G. and Fank, J.: Determining water and nitrogen balances for beneficial management practices using lysimeters at Wagna test site (Austria). Science of the Total Environment 499 (2014) 448-462. Meissner, R., Seeger, J., Rupp, H., Seyfarth, M., and Borg, H.: Measurement of dew, fog, and rime with a high-precision gravitation lysimeter, J. Plant Nutr. Soil Sci. 2007, 170, 335-344. Peters, A., Nehls, T., Schonsky, H., and Wessolek, G.: Separating precipitation and evapotranspiration from noise - a

  10. Real time dynamics of Si magic clusters mediating phase transformation: Si(111)-(1 1) to (7 7) reconstruction revisited

    NASA Astrophysics Data System (ADS)

    Ong, Wei Jie; Tok, Eng Soon

    2012-07-01

    Using Scanning Tunneling Microscope (STM), we show that the surface undergoes phase transformation from disordered "1 1" to (7 7) reconstruction which is mediated by the formation of Si magic clusters. Mono-disperse Si magic clusters of size ~ 13.5 0.5 can be formed by heating the Si(111) surface to 1200 C and quenching it to room temperature at cooling rates of at least 100 C/min. The structure consists of 3 tetra-clusters of size ~ 4.5 ? similar to the Si magic clusters that were formed from Si adatoms deposited by Si solid source on Si(111)-(7 7) [1]. Using real time STM scanning to probe the surface at ~ 400 C, we show that Si magic clusters pop up from the (1 1) surface and form spontaneously during the phase transformation. This is attributed to the difference in atomic density between "disordered 1 1" and (7 7) surface structures which lead to the release of excess Si atoms onto the surface as magic clusters.

  11. Circulation in Drake Passage revisited using new current time series and satellite altimetry: 1. The Yaghan Basin

    NASA Astrophysics Data System (ADS)

    Ferrari, Ramiro; Provost, Christine; Renault, Alice; SennChael, Nathalie; Barr, Nicolas; Park, Young-Hyang; Lee, Jae Hak

    2012-12-01

    The complex bathymetry of the Drake Passage and the meridional extent of the Shackleton Fracture Zone, in particular, force the Subantarctic Front (SAF) and the Polar Front (PF) to veer to the north, and the flow of the Antarctic Circumpolar Current concentrates in the Yaghan Basin. We have studied the circulation in the Yaghan Basin, using 3 years of velocity data (January 2006-March 2009) at five mooring sites and 18 years of satellite altimetry data. Mean velocities at our mooring sites show a dominant eastward component which decreases with depth, as expected, with a notable exception in the center of the Yaghan Basin, where mean velocities reveal a dominant westward component increasing with depth. The mooring data suggest the existence of a permanent, strong deep cyclonic circulation over the Yaghan seafloor depression in the northeastern part of the Yaghan Basin. The in situ data provide the first opportunity to compare altimetry-derived velocities with high temporal resolution near-surface current meter velocities in a large eddy kinetic energy environment at high latitudes. Globally, altimetry-derived velocities compare rather well with the in situ velocities at 500 m depth both in strength and direction. Correlations are high between the in situ velocities and the surface velocities derived from satellite altimetric data. Mean sea level estimates lead to reasonable mean surface velocities with, however, a slight underestimation of the mean velocity at the mean location of the SAF on the continental slope and a more important underestimation of the westward current in the center of the Yaghan Basin. A dominant mode of velocity variations (23% of the variance) is observed both in the in situ and satellite data, corresponding to a strong southward meander of the SAF upstream of the mooring line and a northward meander of the PF downstream of the latter. The 18 yearlong altimetry time series shows that the mode is robust and has a strong semiannual component.

  12. Relationship between short-time self-diffusion and high-frequency viscosity in charge-stabilized dispersions

    NASA Astrophysics Data System (ADS)

    Bergenholtz, J.; Horn, F. M.; Richtering, W.; Willenbacher, N.; Wagner, N. J.

    1998-10-01

    Experimental determination of both the short-time self-diffusion coefficient and the high-frequency viscosity are reported for model charge-stabilized dispersions. Despite the charged nature of the particles, we find that both quantities are insensitive to direct interparticle interactions. Quantitative agreement between the experimental data and micromechanical hard sphere theory is observed for a range of particle sizes and added salt content. However, while the reciprocal of the short-time self-diffusion coefficient shows a similar concentration dependence as the high-frequency viscosity, the two do not obey a generalized Stokes-Einstein relation. The violation is due to subtle differences in hydrodynamic interactions between the two particle motions, in agreement with theory and simulation.

  13. Short contact time direct coal liquefaction using a novel batch reactor. Quarterly progress report, January 1--May 15, 1995

    SciTech Connect

    Klein, M.T.; Calkins, W.H.

    1995-05-31

    The objective of this research is to optimize the design and operation of the bench scale batch reactor for coal liquefaction at short contact times (0.01 to 10 minutes or longer). Additional objectives are to study the kinetics of direct coal liquefaction particularly at short reaction times, and to investigate the role of the organic oxygen components of coal and their reaction pathways during liquefaction. Experimental progress is reported for uncatalyzed liquefactions, catalyzed liquefactions, liquefaction in the presence of solvents other than tetralin, and kinetics of gas formation during coal liquefaction. Analytical methods were developed for the determination of the boiling range of coal liquids by thermogravimetric analysis and the determination of phenolic hydroxyl in coal, coal liquids, and coal residues.

  14. Microstructural evolution in Al-Zn-Mg-Cu-Sc-Zr alloys during short-time homogenization

    NASA Astrophysics Data System (ADS)

    Liu, Tao; He, Chun-nian; Li, Gen; Meng, Xin; Shi, Chun-sheng; Zhao, Nai-qin

    2015-05-01

    Microstructural evolution in a new kind of aluminum (Al) alloy with the chemical composition of Al-8.82Zn-2.08Mg-0.80Cu-0.31Sc-0.3Zr was investigated. It is found that the secondary phase MgZn2 is completely dissolved into the matrix during a short homogenization treatment (470C, 1 h), while the primary phase Al3(Sc,Zr) remains stable. This is due to Sc and Zr additions into the Al alloy, high Zn/Mg mass ratio, and low Cu content. The experimental findings fit well with the results calculated by the homogenization diffusion kinetics equation. The alloy shows an excellent mechanical performance after the short homogenization process followed by hot-extrusion and T6 treatment. Consequently, a good combination of low energy consumption and favorable mechanical properties is obtained.

  15. Design and simulation of a speech analysis-synthesis system based on short-time Fourier analysis

    Microsoft Academic Search

    RONALD W. SCHAFER; LAWRENCE R. RABINER

    1973-01-01

    This paper discusses the theoretical basis for representation of a speech signal by its short-time Fourier transform. The results of the theoretical studies were used to design a speech analysis-synthesis system which was simulated on a general-purpose laboratory digital computer system. The simulation uses the fast Fourier transform in the analysis stage and specially designed finite duration impulse response filters

  16. Real-time forecasting of short-term irrigation canal demands using a robust multivariate Bayesian learning model

    Microsoft Academic Search

    Andres M. Ticlavilca; Mac McKee; Wynn R. Walker

    In the lower Sevier River basin in Utah, the travel times between reservoir releases and arrival at irrigation canal diversions\\u000a limit the reservoir operation in enabling delivery changes, which may not be compatible with the on demand schedule in the\\u000a basin. This research presents a robust machine learning approach to forecast the short-term diversion demands for three irrigation\\u000a canals. These

  17. Modal analysis of broadband acoustic receptions at 3515-km range in the North Pacific using short-time Fourier techniques

    Microsoft Academic Search

    Kathleen E. Wage; Arthur B. Baggeroer; James C. Preisig

    2003-01-01

    In 1995-1996 the Acoustic Thermometry of Ocean Climate (ATOC) experiment provided an opportunity to study long-range broadband transmissions over a series of months using mode-resolving vertical arrays. A 75-Hz source off the California coast transmitted broadband pulses to receiving arrays in the North Pacific, located at ranges of 3515 and 5171 km. This paper develops a short-time Fourier transform (STFT)

  18. Short-pulse Laser Induced Transient Structure Formation and Ablation Studied with Time-resolved Coherent XUV-scattering

    NASA Astrophysics Data System (ADS)

    Sokolowski-Tinten, Klaus; Barty, Anton; Boutet, Sebastien; Shymanovich, Uladzimir; Chapman, Henry; Bogan, Mike; Marchesini, Stefano; Hau-Riege, Stefan; Stojanovic, Nikola; Bonse, Jrn; Rosandi, Yudi; Urbassek, Herbert M.; Tobey, Ra'anan; Ehrke, Henri; Cavalleri, Andrea; Dsterer, Stefan; Redlin, Harald; Frank, Matthias; Bajt, Sasa; Schulz, Joachim; Seibert, Marvin; Hajdu, Janos; Treusch, Rolf; Bostedt, Christoph; Hoener, M.; Mller, T.

    2010-10-01

    The structural dynamics of short-pulse laser irradiated surfaces and nano-structures has been studied with nm spatial and ultrafast temporal resolution by means of single-shot coherent XUV-scattering techniques. The experiments allowed us to time-resolve the formation of laser-induced periodic surface structures, and to follow the expansion and disintegration of nano-objects during laser ablation.

  19. Simulation of the gallium nitride-based pulse mode X-ray detector for short-time applications

    Microsoft Academic Search

    Ali Taheri; Shahyar Saramad; Asghar Maleki; Saeed Setayeshi

    2012-01-01

    The purpose of this work is to simulate gallium nitride (GaN)-based X-ray pulse mode detector to study the capability of GaN for X-ray detection in short-time applications. The simulation was performed using Monte Carlo (MC) and finite-element methods. The history of charges created by X-photons inside the detector was obtained using the MC results, while the computation of electric field,

  20. Simulation of the gallium nitride-based pulse mode X-ray detector for short-time applications

    Microsoft Academic Search

    Ali Taheri; Shahyar Saramad; Asghar Maleki; Saeed Setayeshi

    2011-01-01

    The purpose of this work is to simulate gallium nitride (GaN)-based X-ray pulse mode detector to study the capability of GaN for X-ray detection in short-time applications. The simulation was performed using Monte Carlo (MC) and finite-element methods. The history of charges created by X-photons inside the detector was obtained using the MC results, while the computation of electric field,

  1. Design for velocity saturated, short-channel CMOS drivers with simultaneous switching noise and switching time considerations

    Microsoft Academic Search

    Yaochao Yang; John R. Brews

    1996-01-01

    Design guidelines for velocity-saturated, short-channel CMOS drivers are presented in this paper based on approximating the package inductance by an effective, lumped, power-supply bus parasitic inductance. A worst-case maximum simultaneous switching noise VGM and gate propagation delay time tD,1\\/2 are treated as performance constraints for which driver design tradeoffs between driver geometry, the maximum number of simultaneously switched drivers, and

  2. Large-Time Asymptotics of Solutions to the Kramers-Fokker-Planck Equation with a Short-Range Potential

    NASA Astrophysics Data System (ADS)

    Wang, Xue Ping

    2015-06-01

    In this work, we use a scattering method to study the Kramers-Fokker-Planck equation with a potential whose gradient tends to zero at the infinity. For short-range potentials in dimension three, we show that complex eigenvalues do not accumulate at low-energies and obtain the low-energy resolvent asymptotics. This, combined with high energy pseudospectral estimates valid in more general situations, gives the large-time asymptotics of solutions in weighted L 2 spaces.

  3. Analyzing short time series data from periodically fluctuating rodent populations by threshold models: A nearest block bootstrap approach

    Microsoft Academic Search

    Kung-Sik Chan; Howell Tong; Nils Chr Stenseth

    2009-01-01

    The study of the rodent fluctuations of the North was initiated in its modern form with Eltons pioneering work. Many scientific\\u000a studies have been designed to collect yearly rodent abundance data, but the resulting time series are generally subject to\\u000a at least two problems: being short and non-linear. We explore the use of the continuous threshold autoregressive (TAR) models\\u000a for

  4. Numerical study of the effect of normalised window size, sampling frequency, and noise level on short time Fourier transform analysis

    NASA Astrophysics Data System (ADS)

    Ota, T. A.

    2013-10-01

    Photonic Doppler velocimetry, also known as heterodyne velocimetry, is a widely used optical technique that requires the analysis of frequency modulated signals. This paper describes an investigation into the errors of short time Fourier transform analysis. The number of variables requiring investigation was reduced by means of an equivalence principle. Error predictions, as the number of cycles, samples per cycle, noise level, and window type were varied, are presented. The results were found to be in good agreement with analytical models.

  5. Short-Time Scale Dynamic Failure Modes in a Through-Silicon-Via (TSV) Flip-Chip Configuration

    E-print Network

    Huang, Chang-Chia

    2010-10-12

    /O interconnections operating at several giga-Hertz clock speed inevitably suffer serious heat dissipation which raises important reliability concerns. Due to the miniaturized component size and complex structures in 3-D flip-chip packages, the possibility... analysis on short- time scale effects due to the practical deficiency of technology to capture waveforms propagating in a IC package at the giga-hertz level. Hence, a finite element analysis (FEA) model is required to "virtually" study the topic...

  6. In vitro Short-Time Killing Activity of PovidoneIodine (Isodine Gargle) in the Presence of Oral Organic Matter

    Microsoft Academic Search

    Akiko Yoneyama; Masaki Shimizu; Makiko Tabata; Junko Yashiro; Toshihiko Takata; Muneo Hikida

    2006-01-01

    In order to estimate the clinical efficacy of a povidone-iodine oral antiseptic (PVP-I) on oral bacterial infectious diseases, we studied the effect of oral organic matter on the in vitro killing activity of PVP-I. In addition, we compared the in vitro short-time killing activity of PVP-I with those of other oral antiseptics using mouth-washing and gargling samples collected from healthy

  7. Short-residence-time hydropyrolysis of coal. Technical progress report, 1 April 1980-30 June 1980

    SciTech Connect

    Saville, D. A.; Russel, W. B.

    1980-01-01

    A fundamental study of the hydropyrolysis of small coal particles at high pressures and short residence times of both solid and gas is underway to elucidate the chemical and physical rate processes governing delineated conditions favorable toward high yields of gas and light aromatic liquids. Our aim is to develop an understanding of short-contract-time hydropyrolysis based on studies which carefully isolate events occurring within single particles from effects due to gas phase reactions or slow quenching of the solid. A novel laboratory reactor has been fabricated which will provide short residence times with rapid heating. Detailed chemical and physical analyses of both the parent coal and the product distribution will be obtained as a function of extent of reaction and the process conditions. This data will then be analyzed in terms of a model for the coupling between the heat and mass transfer and chemical reactions within an individual particle. During the past quarter the reactor system was readied for kinetic studies of weight loss with PSOC 102, Pittsburgh seam HVA bituminous.

  8. Countertransference revisited.

    PubMed

    Mills, Jon

    2004-08-01

    A female patient of mine recounts her week. I listen with interest, waiting for her to arrive at particular conclusions. She has suffered a great deal and still does, but prefers not to dwell on it. My interest turns into patience as she continues to talk but circumvents her discontent. She is adroit at avoidance, but easily offended when I point such things out. "I'd better wait" I think. I grow more aware that I must encourage her digressions. I feel frustrated. Getting further and further away, she skirts the issue with supple grace, then strays off into tangentiality. I forget her point and lose my focus, then get down on myself. The opportunity is soon gone. I glance at the clock as her monologue drones on into banality. I grow more uninterested and distant. There is a subtle irritation to her voice; a whiney indecisive ring begins to pervade my consciousness. I home in on her mouth with aversion, watching apprehensively as this disgusting hole flaps tirelessly but says nothing. It looks carnivorous, voracious. Now she is unattractive, something I have noticed before. I forget who my next patient is. I think about the meal I will prepare for my wife this evening, then glance at the time once more. Then I am struck: Why am I looking at the clock? So soon? The session has just begun. I catch myself. What is going on in me, between us? I am detached, but why? Is she too feeling unattuned, disconnected? I am failing my patient. What is her experience of me? I lamentingly confess that I do not feel I have been listening to her, and wonder what has gone wrong between us. I ask her if she has noticed. We talk about our feelings, our impact on one another, why we had lost our sense of connection, what it means to us. I instantly feel more involved, rejuvenated, and she continues, this time with me present. Her mouth is no longer odious, but sincere and articulate. She is attractive and tender; I suddenly feel empathy and warmth toward her. We are now very close. I am moved. Time flies, the session is soon over; we do not want it to end. PMID:15491945

  9. Myolysis Revisited

    PubMed Central

    2008-01-01

    Numerous procedures have been developed in recent decades that claim to provide significant improvement in myoma status without hysterectomy. However, what is the cost in time and money of these procedures? This is a review of the current literature regarding these recent procedures to determine which, if any, is the best treatment for myomas. We conducted a search of PubMed using the terms bipolar-, cryo-, radiofrequency, laparoscopic-, focused high-energy MRI-guided ultrasound, and MRI-guided laser myolysis to identify reports of the various procedures. Based on these published reports, we describe the various types of myolysis performed in multiple patients in outpatient facilities including patient outcomes, complications, cost, and efficiency of the procedures. PMID:19275864

  10. Vessel failure time for a low-pressure short-term station blackout in a BWR-4

    SciTech Connect

    Carbajo, J.J. (Martin Marietta Energy System, Oak Ridge, TN (United States))

    1993-01-01

    A low-pressure, short-term station blackout severe accident sequence has been analyzed using the MELCOR code, version 1.8.1, in a boiling water reactor (BWR)-4. This paper presents a sensitivity study evaluating the effect of several MELCOR input parameters on vessel failure time. Results using the MELCOR/CORBH package and the BWRSAR code are also presented and compared to the MELCOR results. These calculated vessel failure times are discussed, and a judgment is offered as to which is the most realistic.

  11. Trait-specific responses of Scots pine to irrigation on a short vs long time scale.

    PubMed

    Feichtinger, Linda M; Eilmann, Britta; Buchmann, Nina; Rigling, Andreas

    2015-02-01

    In xeric environments, an increase in drought is related to reduced forest productivity and to enhanced mortality. However, predictions of future forest development remain difficult as the mechanisms underlying the responses of mature trees to long-term variations in water availability are not well understood. Here, we aimed to compare the adjustments in radial growth and morphological needle and shoot traits of mature Scots pine (Pinus sylvestris L.) growing along open water channels with those of control trees growing under naturally dry conditions at three sites in Valais, an inner-Alpine dry valley of Switzerland. The trees growing along two channels had been irrigated since germination (>70 years), whereas those along another previously drained channel had been irrigated only from 2010 to 2012, when the channel was re-established, and could thus be used to quantify the short-term effects of re-irrigation. Linear mixed models revealed that needle and shoot lengths as well as early- and late-wood basal area increments (BAIs) were most responsive to short-term and long-term irrigation. However, the magnitude of the response to the short-term irrigation exceeded that of the long-term irrigation. An extreme drought during the first half of 2011 led to an immediate decrease in the needle length, needle width, and early- and late-wood BAIs of the control trees, whereas the shoot length and needle numbers of control trees reacted with a 1-year delay to the extreme drought, as the shoots were responding to water availability of previous year's summer. Such negative responses to dry climatic conditions were even found in irrigated trees at one of our sites, which might be linked to tree growth becoming more sensitive to drought with increasing tree height and leaf area. In order to improve predictions of future forest development, long-term studies are necessary that consider lagged responses and adjustment processes of trees to changes in water availability. PMID:25631531

  12. Short-residence-time hydropyrolysis. Technical progress report, 1 October-31 December 1980 and 1 January-31 March 1981

    SciTech Connect

    Saville, D.A.; Russel, W.B.

    1981-01-01

    A fundamental study of the hydropyrolysis of small coal particles at high pressures and short residence times of both solid and gas is underway to elucidate the chemical and physical rate processes governing the yield. While previous experiments have roughly delineated conditions favorable toward high yields of gas and light aromatic liquids, a more basic understanding is needed for rational evaluation of designs involving different reactor geometries, coals and processing conditions for the production of a variety of liquid products. Our aim is to develop an understanding of short-contract-time hydropyrolysis based on studies which carefully isolate events occurring within single particles from effects due to gas phase reactions or slow quenching of the solid. A novel laboratory reactor has been fabricated which provides short residence times with rapid heating. Detailed chemical and physical analyses of both the parent coal and the product distribution are obtained as a function of extent of reaction and the process conditions. This data will then be analyzed in terms of a model for the coupling between the heat and mass transfer and chemical reactions within an individual particle Roughly 225 runs were made with PSOC 102, Pittsburgh Seam HVA bituminous. We now have results at several different pressures (0.1 Torr-1500 psi), temperatures (to 900/sup 0/C), heating rates (to 10/sup 4/ /sup 0/c/s ) and particle sizes (50 ..mu..m, 85..mu..m, 125..mu..m)). All data were taken in helium and cover isothermal reaction times from 0 to 30s; a zero length reaction time is defined as heating to the prescribed temperature followed by an immediate quench.

  13. Panspermia revisited

    NASA Astrophysics Data System (ADS)

    Horneck, Gerda

    "Panspermia", coined by S. Arrhenius in 1903, suggests that microscopic forms of life, e.g., bacterial spores, can be dispersed in space by the radiation pressure from the Sun thereby seeding life from one planet to another or even beyond our Solar System. Being ignored for almost the rest of the century, the scenario of interplanetary transfer of life has received increased support from recent discoveries, such as the detection of Martian meteorites and the high resistance of microorganisms to outer space conditions. With the aid of space technology and adequate laboratory devices the following decisive step required for viable transfer from one planet to another have been tested: (i) the escape process, i.e. impact ejection into space; (ii) the journey through space over extended periods of time; and (iii) the landing process, i.e. non-destructive deposition of the biological material on another planet. In systematic shock recovery experiments within a pressure range observed in Martian meteorites (5-50 GPa) a vital launch window of 5-40 GPa has been determined for spores of Bacillus subtilis and the lichen Xanthoria elegans, whereas this window was restricted to 5-10 GPa for the endolithic cyanobaterium Chroococcidiopsis. Traveling through space implies exposure to high vacuum, an intense radiation regime of cosmic and solar origin and high temperature fluctuations. In several space experiments the biological efficiency of these different space parameters has been tested: extraterrestrial solar UV radiation has exerted the most deleterious effects to viruses, as well as to bacterial and fungal spores; however shielding against this intense insolation resulted in 70 % survival of B. subtilis spores after spending 6 years in outer space. Lichens survived 2 weeks in space, even without any shielding. The entry process of microorganisms has been recently tested in the STONE facility attached to the heat shield of a reentry capsule. The data support the scenario of "Lithopanspermia", which assumes that impact-expelled rocks serve as interplanetary transfer vehicles for microorganisms colonizing those rocks. Literature: Stffler D, Horneck G, Ott S, Hornemann, U, Cockell CS, Moeller R, Meyer C, de Vera J-P, o Fritz J, Artemieva NA,.Experimental evidence for the potential impact ejection of viable microorganisms from Mars and Mars-like planets (2007) Icarus, 186, 585-588. Sancho, L.G., de la Torre, R., Horneck, G., Ascaso, C., de los Rios, A., Pintado, A., Wierzchos, J. and Schuster, M. (2007) Lichens survive in space: Results from the 2005 LICHENS experiment. Astrobiology, 7, 443-454. Mileikowsky C, Cucinotta F, Wilson J W, Gladman B, Horneck G, Lindegren L, Melosh J, Rickman H, Valtonen M, Zheng J Q (2000) Natural transfer of viable microbes In space, Part 1: From Mars to Earth and Earth to Mars, Icarus, 145, 391-427. Nicholson WL, Munakata N, Horneck G, Melosh HJ, and Setlow P (2000) Resistance of Bacillus endospores to extreme terrestrial and extraterrestrial environments, Microb. Mol. Biol. Rev. 64, 548-572.

  14. Time-resolved plasma spectroscopy of thin foils heated by a relativistic-intensity short-pulse laser.

    PubMed

    Audebert, P; Shepherd, R; Fournier, K B; Peyrusse, O; Price, D; Lee, R W; Springer, P; Gauthier, J-C; Klein, L

    2002-12-01

    Time-resolved K-shell x-ray spectra are recorded from sub-100 nm aluminum foils irradiated by 150-fs laser pulses at relativistic intensities of Ilambda(2)=2 x 10(18) W microm(2)/cm(2). The thermal penetration depth is greater than the foil thickness in these targets so that uniform heating takes place at constant density before hydrodynamic motion occurs. The high-contrast, high-intensity laser pulse, broad spectral band, and short time resolution utilized in this experiment permit a simplified interpretation of the dynamical evolution of the radiating matter. The observed spectrum displays two distinct phases. At early time, < or =500 fs after detecting target emission, a broad quasicontinuous spectral feature with strong satellite emission from multiply excited levels is seen. At a later time, the He-like resonance line emission is dominant. The time-integrated data is in accord with previous studies with time resolution greater than 1 ps. The early time satellite emission is shown to be a signature of an initial large area, high density, low-temperature plasma created in the foil by fast electrons accelerated by the intense radiation field in the laser spot. We conclude that, because of this early time phenomenon and contrary to previous predictions, a short, high-intensity laser pulse incident on a thin foil does not create a uniform hot and dense plasma. The heating mechanism has been studied as a function of foil thickness, laser pulse length, and intensity. In addition, the spectra are found to be in broad agreement with a hydrodynamic expansion code postprocessed by a collisional-radiative model based on superconfiguration average rates and on the unresolved transition array formalism. PMID:12513417

  15. Determination of formation permeablility in a tight gas reservoir from short-time drawdown data

    E-print Network

    Kuo, Tsai-Bao

    1983-01-01

    . 84 85 14 Formation Permeabilities Calculated Skin Factors, Well V. B. with Different 86 LIST OF FIGURES Figure Page Flow Chart for Calculating Formation Permeability. . . . . . 8 Kc/Ka Ratio vs. Dimensionless Time for Constant Rate Drawdown... Test, Skin Factor = 0 . . . . . . . . . . . . . . . 13 Kc/Ka Ratio vs. Oimensionless Time for Constant Rate Drawdown Test, Skin Factor = 1 . . . . . . . . . . . . . . . 14 Kc/Ka Ratio vs. Oimensionless Time for Constant Rate Drawdown Test, Skin...

  16. Short-time-scale (year) variations of petroleum fluids from the U.S. Gulf Coast

    NASA Astrophysics Data System (ADS)

    Whelan, Jean K.; Eglinton, Lorraine; Kennicutt, Mahlon C.; Qian, Yaorong

    2001-10-01

    Evolving short-term (less than 5 yr) compositional changes in hydrocarbon charge from some Eugene Island Block 330 (EI-330) wells are demonstrated. Storage, analytical, and production artifacts are shown to be minimal. In some wells, compositions remain constant from 1985 to 1993, whereas in others in the same reservoir, significant changes are observed. In some cases, temporal variability is greater than spatial variability. Maximum temporal change is strongest for specific compounds: toluene and C 6 to C 9 normal alkanes, but is also observed to a lesser extent for higher-molecular-weight components (up to n-C 32). Principal coordinate analysis shows the highest degree of overall temporal compositional change over an 8-yr period in the shallowest wells where there is also evidence of biodegradation. Small temporal compositional changes are also observed in two deeper wells that are below the thermal window favorable for biodegradation. An exception is an unusual oil, where a very large increase in toluene, as well as smaller changes in a number of n-alkanes, was observed in 1993. The ? 13C compound-specific isotopic signature of toluene, in addition to several other C 7-C 8 compounds in this oil, yields convincing evidence that it is related to the same family as other EI-330 oils and unlikely to be due to a drilling or laboratory contaminant. Minor isotopic differences in other C 7 compounds (1.5) are consistent with extensive gas washing of this oil. The short-term compositional changes in EI-330 oils are attributed to gas washing, which causes overprinting of biodegraded oils with light n-alkanes in shallower GA and HB reservoirs where oils are currently being biodegraded in situ. Patterns of smaller changes in heavier compounds in both shallower and deeper wells are also consistent with this interpretation.

  17. Theorem on the Distribution of ShortTime Single Particle Displacements with Physical

    E-print Network

    and nanometer 1 #12; length scales[13--17] and to heterogeneous dynamics in supercooled liquids and glasses.[18) mixtures[17] is in progress. The main advantage of the Green's functions over hydrodynamics that a single particle of component # is at a position r at time t given that it was at a position r # at time

  18. EUROGRAPHICS 2002 / N.N. Short Presentations Real Time Animated Grass

    E-print Network

    Heidrich, Wolfgang

    time step, each vertex is moved in accordance with the local wind direction a distance de- termined surfaces for many years. Kajiya and Kay1 proposed using volumetric textures to ren- der furry surfaces complex phenomena such as grass or fur in real time. Lengyel4 produced a very convincing furry bunny using

  19. Comparison of Short-Term and Time-Independent Earthquake Forecast Models for Southern California

    Microsoft Academic Search

    Agnes Helmstetter; Yan Y. Kagan; David D. Jackson

    2006-01-01

    We have initially developed a time-independent forecast for southern California by smoothing the locations of magnitude 2 and larger earthquakes. We show that using small m 2 earthquakes gives a reasonably good prediction of m 5 earthquakes. Our forecast outperforms other time-independent models (Kagan and Jackson, 1994; Frankel et al., 1997), mostly because it has higher spatial resolution. We have

  20. FALSE DETERMINATIONS OF CHAOS IN SHORT NOISY TIME SERIES. (R828745)

    EPA Science Inventory

    A method (NEMG) proposed in 1992 for diagnosing chaos in noisy time series with 50 or fewer observations entails fitting the time series with an empirical function which predicts an observation in the series from previous observations, and then estimating the rate of divergenc...

  1. Short communication: Decrease in rumination time as an indicator of the onset of calving.

    PubMed

    Bchel, S; Sundrum, A

    2014-05-01

    The aim of this study was to investigate whether rumination time (RT) is affected by the onset of calving. The relationship between both feeding time and dry matter intake (DMI) to the onset of calving was also examined. In addition, the correlation between feeding behavior characteristics, described here as RT, feeding time, and DMI, was evaluated. Under test conditions, the feeding behavior of pregnant Holstein cows was recorded from the time when they were moved into calving pens (usually 7 to 5d prepartum) until the onset of calving. Feeding time and DMI were recorded by automatic feed bins; RT was measured continuously by a measuring halter based on electromyography (DairyCheck; BITSz Engineering GmbH, Zwickau, Germany), which constitutes a new approach regarding feeding behavior detection. Data analysis related to the final 72 h, before the onset of calving, which were divided into twelve 6-h blocks. The last 6h (one 6-h block) before calving were compared with the 72- to 7-h time frame (11 times 6-h blocks) before calving, which was defined as the reference period. For this time period, feeding behavior data for 17 cows was fully available, which was the precondition for data analysis. In the final 6h before imminent birth, RT was significantly reduced. During this time, it was found that the mean minimum RT was 69.9 28.5 min/6h compared with the mean RT of 95.5 30.8 min/6h in the reference period. The average decrease in RT was 27% (25.6 min/6h). In addition, feeding time and DMI were significantly reduced. The average decrease in feeding time was 57% (20.8 min/6h), and in DMI it was 56% (1.9 kg/6h). High correlation coefficients between feeding behavior characteristics were only found between feeding time and DMI. Values of feeding behavior among cows were characterized by high variability. Recording RT can serve as a useful tool for predicting the timing of birth for dairy cows, but further research is necessary. PMID:24612813

  2. Short-time OD matrix estimation for a complex junction using Fuzzy-Timed High-Level Petri Nets

    Microsoft Academic Search

    Krystyna Biletska; Marie-Helene Masson; Sophie Midenet

    2010-01-01

    The OD matrix at a signalised junction estimated for traffic light cycle represents a crucial information for trans- portation systems. A new dynamic two-steps method is proposed to estimate such an OD matrix. First, a vehicle conservation law is build in a dynamical way for each traffic light cycle using Fuz zy- Timed High-Level Petri Nets (FTHN). It is represented

  3. Critical-current density enhancement in HTSC ceramics under CO2 laser irradiation and short-time thermal annealing

    NASA Astrophysics Data System (ADS)

    Mikhailova, G. N.; Prokhorov, Alexander M.; Troitskii, A. V.; Mikhailov, B. P.; Grigorashev, D. I.; Kazin, P. E.; Lennikov, V. V.; Aksenova, T. D.

    1998-05-01

    We report the results of designed method of the recrystallization of Bi(2212,2223) and YBCO(123) HTSC ceramics, consisting of laser amorphization and short-time thermal annealing, which was used to enhance the structure and the transport properties of HTCS ceramics prepared by pressing. Cw CO2 laser ((lambda) equals 10.6 micrometers ) with the average power 100 W was used as a laser source. Short- duration melting of high-Tc superconducting ceramics by CO2 laser, in combination with a short heat treatment, produced a denser fine-grained structure (grain size 2 - 3 micrometers ). The resultant structure contributed to a considerable increase in the critical current of the superconductors: in 1 - 2 orders of magnitude depending on a type of the material at 77 K and 2 - 3 orders at 20 K. Our results demonstrate the feasibility of laser amorphization of HTSC ceramics in an almost single-phase state with its chemical composition close the composition of the initial unmelted compound and with an almost unchanged area of the fused zone. Heat treatment of this amorphized zone restored the chemical composition to its initial ratio and made it possible to form grains of different types.

  4. Time-resolved observation of fast domain-walls driven by vertical spin currents in short tracks

    SciTech Connect

    Sampaio, Joao; Lequeux, Steven; Chanthbouala, Andre; Cros, Vincent; Grollier, Julie [Unit Mixte de Physique CNRS/Thales and Universit Paris-Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France)] [Unit Mixte de Physique CNRS/Thales and Universit Paris-Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France); Metaxas, Peter J. [Unit Mixte de Physique CNRS/Thales and Universit Paris-Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France) [Unit Mixte de Physique CNRS/Thales and Universit Paris-Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France); School of Physics, M013, University of Western Australia, 35 Stirling Highway, Crawley WA 6009 (Australia); Matsumoto, Rie; Yakushiji, Kay; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji [National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)] [National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Nishimura, Kazumasa; Nagamine, Yoshinori; Maehara, Hiroki; Tsunekawa, Koji [Process Development Center, Canon ANELVA Corporation, Kurigi 2-5-1, Asao, Kawasaki, Kanagawa 215-8550 (Japan)] [Process Development Center, Canon ANELVA Corporation, Kurigi 2-5-1, Asao, Kawasaki, Kanagawa 215-8550 (Japan)

    2013-12-09

    We present time-resolved measurements of the displacement of magnetic domain-walls (DWs) driven by vertical spin-polarized currents in track-shaped magnetic tunnel junctions. In these structures, we observe very high DW velocities (600?m/s) at current densities below 10{sup 7}?A/cm{sup 2}. We show that the efficient spin-transfer torque combined with a short propagation distance allows avoiding the Walker breakdown process and achieving deterministic, reversible, and fast (?1?ns) DW-mediated switching of magnetic tunnel junction elements, which is of great interest for the implementation of fast DW-based spintronic devices.

  5. Spatial and Time Coincidence Detection of the Decay Chain of Short-Lived Radioactive Nuclei

    SciTech Connect

    Granja, Carlos; Jakubek, Jan; Platkevic, Michal; Pospisil, Stanislav [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, 128 00 Prague 2 (Czech Republic); Koester, Ulli [Institute Laue Langevin, 6 rue Jules Horowitz, F-38042 Grenoble Cedex 9 (France)

    2010-08-04

    The quantum counting position sensitive pixel detector Timepix with per-pixel energy and time resolution enables to detect radioactive ions and register the consecutive decay chain by simultaneous position-and time-correlation. This spatial and timing coincidence technique in the same sensor is demonstrated by the registration of the decay chain {sup 8}He{yields}{sup {beta} 8}Li and {sup 8}Li{yields}{sup {beta}-} {sup 8}Be{yields}{alpha}+{alpha} and by the measurement of the {beta} decay half-lives. Radioactive ions, selectively obtained from the Lohengrin fission fragment spectrometer installed at the High Flux Reactor of the ILL Grenoble, are delivered to the Timepix silicon sensor where decays of the implanted ions and daughter nuclei are registered and visualized. We measure decay lifetimes in the range {>=}{mu}s with precision limited just by counting statistics.

  6. 1374 IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, VOL. 49, NO. 11, NOVEMBER 2002 A Method for Determinism in Short Time Series, and its

    E-print Network

    for Determinism in Short Time Series, and its Application to Stationary EEG Jaeseung Jeong*, John C. Gore is based on the obser- vation that the trajectory of a time series generated from a differentiable vectors in the trajectory reconstructed from the time series is calculated as a function of time

  7. Calculation of point-to-point short time and rare trajectories with boundary value formulation

    E-print Network

    Elber, Ron

    equations of motions. While highly successful in many cases, significant limitations remain. One the overall rate of an ensemble of these trajectories (or the average time of reaction) can be very long even;6 partition function ( )( )( )exp ,Z E X Q dXdQ= - ). With the initia

  8. Diffusion of bistable oscillators driven by colored noise: Short-correlation-time approximation versus Hnggi's ansatz

    Microsoft Academic Search

    F. Marchesoni

    1987-01-01

    The problem of the activation rate in overdamped (Smoluchowski) bistable oscillators subject to colored noise with correlation time tau is discussed in detail. We show that a nontrivial prescription (the so-called Hnggi's ansatz) for truncating the tau expansion of the Fokker-Planck equation describing this class of processes can reproduce the results of both analog and digital simulations in the regime

  9. Short term effect of rainfall on suspected malaria episodes at Magaria, Niger: a time series study

    Microsoft Academic Search

    Jean-Franois Jusot; Oumarou Alto

    2011-01-01

    Epidemiological patterns of malaria are influenced by different kinds of climate. In Sahelian countries, the link between climatic factors and malaria is still insufficiently quantified. The aim of this work was to conduct a time-series study of rainfall to estimate the increased risk of malaria morbidity.Daily suspected malaria episodes among subjects of all ages were collected retrospectively in three health

  10. UHURU observations of short-time-scale variations of the Crab

    Microsoft Academic Search

    W. Forman; R. Giacconi; C. Jones; E. Schreier; H. Tananbaum

    1974-01-01

    We have analyzed Uhuru X-ray observations of the Crab and found statistically significant variability in the intensity on time scales of several tenths of a second. Our results imply either that the X-ray emission from the pulsar NP 0532 is highly variable or that we have observed a previously undetected compact source of X-rays.

  11. Uhuru observations of short-time-scale variations of the Crab. [X ray emission from pulsar

    NASA Technical Reports Server (NTRS)

    Forman, W.; Giacconi, R.; Jones, C.; Schreier, E.; Tananbaum, H.

    1974-01-01

    We have analyzed Uhuru X-ray observations of the Crab and found statistically significant variability in the intensity on time scales of several tenths of a second. Our results imply either that the X-ray emission from the pulsar NP 0532 is highly variable or that we have observed a previously undetected compact source of X-rays.

  12. First time nuclear material detection by one short-pulse-laser-driven neutron

    E-print Network

    Kurien, Susan

    counters; one detector containing a 2 kg sample of depleted uranium, and the other one empty for background comparison. A single shot interrogation of the depleted uranium sample, showed a clear signal from the delayed neutrons in the detector with uranium, compared with the background, and with the typical time

  13. Comparison Groups in Short Interrupted Time-Series: An Illustration Evaluating No Child Left Behind

    ERIC Educational Resources Information Center

    Wong, Manyee; Cook, Thomas D.; Steiner, Peter M.

    2009-01-01

    Interrupted time-series (ITS) are often used to assess the causal effect of a planned or even unplanned shock introduced into an on-going process. The pre-intervention slope is supposed to index the causal counterfactual, and deviations from it in mean, slope or variance are used to indicate an effect. However, a secure causal inference is only

  14. We have been around only a very short time. Amy Pollack

    E-print Network

    Pollack, Robert

    . Dinosaurs would appear in the middle of volume 30. They would for the most part be wiped out by an asteroid, because archeobacteria, the first forms of life, would appear in the seas in vol- ume 22. Bacteria would-celled forms of life like paramecia and diatoms would appear for the first time in volume 25. Living things

  15. A Short-Time Quantum Mechanical Expansion Approach to Vibrational Relaxation Eran Rabani*,

    E-print Network

    Rabani, Eran

    of the vibrational relaxation of a probe molecule in a condensed phase host has occupied a central place in physical-coupling theories of liquids, the "binary" portion of the memory function for a given time correlation function The "viscoelastic" theory of collective density fluctua- tions in liquids involves a continued fractional

  16. Short-lived excited triplet states studied by time-resolved EPR spectroscopy

    Microsoft Academic Search

    Noboru Hirota; Seigo Yamauchi

    2003-01-01

    In this review, we present an overview of the application of time-resolved electron paramagnetic resonance (TREPR) to the study of excited triplet states. After a brief discussion of background and experimental methods, triplet properties clarified by TREPR are reviewed to show how TREPR provides rich information about electronic and molecular structures and dynamic properties of the lowest excited triplet states.

  17. Short communication Assessing in near real time the impact of the April 2010 Eyjafjallajkull

    E-print Network

    Paris-Sud XI, Universit de

    data that was available in near real-time. We rely on a combination of atmospheric dispersion modelling of long range transport of trace species in the atmosphere (Stohl, 2001). The fact that the plume affected atmospheric long range transport case studies to date. In addition, this plume presented a clear microphysical

  18. SHORT COMMUNICATION Effects of time and rainfall on PCR success using DNA

    E-print Network

    was to determine the length of time a fecal pellet from a Sitka black-tailed deer (Odocoileus hemionus sitkensis of DNA from ungulate pellets. Keywords DNA degradation Feces Microsatellites Odocoileus hemionus with limited road access, such as Sitka black-tailed deer (Odo- coileus hemionus sitkensis) in the temperate

  19. Damped-amplitude & polynomial frequency model for short-time ambient vibrations of a building

    E-print Network

    Paris-Sud XI, Universit de

    -frequency model is transformed to the physical damping model, under which the estimated signal is decomposed in "The Eighth International Conference on Condition Monitoring and Machinery Failure Prevention based on power spectral density, instead, they are regarded as time-varying functions even in a few

  20. Google Scholar revisited

    Microsoft Academic Search

    Pter Jacs

    2008-01-01

    Purpose The purpose of this paper is to revisit Google Scholar. Design\\/methodology\\/approach This paper discusses the strengths and weaknesses of Google Scholar. Findings The Google Books project has given a massive and valuable boost to the already rich and diverse content of Google Scholar. The downside of the growth is that significant gaps remain for top ranking

  1. Italy Revisited: The Encyclopedia

    E-print Network

    Epstein, Steven A.

    2005-01-01

    , but so do many others who do not have their own entries. More justiable and useful are the entries on Al- Farabi, Averroes, Avicenna, and other medieval Muslim authors, ITALY REVISITED | 561 though none of these people have any actual connection to medi...

  2. Anodic Polarization Curves Revisited

    ERIC Educational Resources Information Center

    Liu, Yue; Drew, Michael G. B.; Liu, Ying; Liu, Lin

    2013-01-01

    An experiment published in this "Journal" has been revisited and it is found that the curve pattern of the anodic polarization curve for iron repeats itself successively when the potential scan is repeated. It is surprising that this observation has not been reported previously in the literature because it immediately brings into

  3. Copper (II) adsorption by the extracellular polymeric substance extracted from waste activated sludge after short-time aerobic digestion.

    PubMed

    Zhang, Zhiqiang; Zhou, Yun; Zhang, Jiao; Xia, Siqing

    2014-02-01

    The extracellular polymeric substance (EPS) extracted from waste activated sludge (WAS) after short-time aerobic digestion was investigated to be used as a novel biosorbent for Cu(2+) removal from water. The EPS consisted of protein (52.6 %, w/w), polysaccharide (30.7 %, w/w), and nucleic acid (16.7 %, w/w). Short-time aerobic digestion process of WAS for about 4 h promoted the productivity growth of the EPS for about 10 %. With a molecular weight of about 1.9 10(6) Da, the EPS showed a linear structure with long chains, and contained carboxyl, hydroxyl, and amino groups. The sorption kinetics was well fit for the pseudo-second-order model, and the maximum sorption capacity of the EPS (700.3 mg Cu(2+)/g EPS) was markedly greater than those of the reported biosorbents. Both Langmuir model and Freundlich model commendably described the sorption isotherm. The Gibbs free energy analysis of the adsorption showed that the sorption process was feasible and spontaneous. According to the complex results of multiple analytical techniques, including scanning electron microscopy, Fourier transform infrared spectroscopy, atomic force microscopy, etc., the adsorption process took place via both physical and chemical sorption, but the electrostatic interaction between sorption sites with the functional groups and Cu(2+) is the major mechanism. PMID:24026202

  4. Time-separated oscillatory fields for high-precision mass measurements on short-lived Al and Ca nuclides

    E-print Network

    S. George; G. Audi; B. Blank; K. Blaum; M. Breitenfeldt; U. Hager; F. Herfurth; A. Herlert; A. Kellerbauer; H. -J. Kluge; M. Kretzschmar; D. Lunney; R. Savreux; S. Schwarz; L. Schweikhard; C. Yazidjian

    2008-01-17

    High-precision Penning trap mass measurements on the stable nuclide 27Al as well as on the short-lived radionuclides 26Al and 38,39Ca have been performed by use of radiofrequency excitation with time-separated oscillatory fields, i.e. Ramsey's method, as recently introduced for the excitation of the ion motion in a Penning trap, was applied. A comparison with the conventional method of a single continuous excitation demonstrates its advantage of up to ten times shorter measurements. The new mass values of 26,27Al clarify conflicting data in this specific mass region. In addition, the resulting mass values of the superallowed beta-emitter 38Ca as well as of the groundstate of the beta-emitter 26Al m confirm previous measurements and corresponding theoretical corrections of the ft-values.

  5. Stability and bifurcation of the Tsodyks-Markram model about short-term synaptic plasticity with time delay

    NASA Astrophysics Data System (ADS)

    Wang, Qiubao

    2014-06-01

    Short-term synaptic plasticity in the Tsodyks-Markram model can lead to unpredictable and complicated network dynamics. In this paper, we present a new Tsodyks-Markram model with time delay as a parameter. The time delay plays a very important role for the dynamics of our model. We report on the existence of Hopf bifurcation in the model for fixed and varied release probability of available neurotransmitters. It is found that there are stability switches, and a supercritical or subcritical Hopf bifurcation occur when the delay passes through a sequence of critical values. We provide numerical results to illustrate our conclusion about stability and obtain the properties of Hopf bifurcation. Moreover, we find the large sensitivity to initial conditions in our model.

  6. Intermediate- to Deep-Water Circulation Changes on Short and Long Time Scales

    E-print Network

    Murphy, Daniel Patrick

    2012-07-16

    coupled to global climate change. If instead, changes in intermediate water circulation controlled seafloor oxygenation, the changes also would likely have impacted heat balance in the Pacific linking such changes to global climate. 1.3. The world... The following chapters lay out three studies focused on defining changes in oceanic circulation during times of global climate change. Each study focuses on a different geographic region (California margin, South Atlantic Ocean, eastern Indian Ocean...

  7. Production of olefins by oxidative dehydrogenation of propane and butane over monoliths at short contact times

    Microsoft Academic Search

    M. Huff; L. D. Schmidt

    1994-01-01

    The autothermal production of olefins from propane or n-butane by oxidative dehydrogenation and cracking in air or oxygen at atmospheric pressure over noble metal coated ceramic foam monoliths at contact times of 5 milliseconds has been studied. On Pt, synthesis gas (CO and H) dominates near its stoichiometry, while olefin production dominates at higher fuel-to-oxygen ratios. No carbon buildup is

  8. Statistics of Particle Trajectories at Short Time Intervals Reveal fN-Scale Colloidal Forces

    Microsoft Academic Search

    Sunil K. Sainis; Vincent Germain; Eric R. Dufresne

    2007-01-01

    We describe and implement a technique for extracting forces from the\\u000arelaxation of an overdamped thermal system with normal modes. At sufficiently\\u000ashort time intervals, the evolution of a normal mode is well described by a\\u000aone-dimensional Smoluchowski equation with constant drift velocity, v, and\\u000adiffusion coefficient, D. By virtue of fluctuation-dissipation, these transport\\u000acoefficients are simply related to conservative

  9. Short time ionic liquids pretreatment on lignocellulosic biomass to enhance enzymatic saccharification

    Microsoft Academic Search

    Uju; Yasuhiro Shoda; Aya Nakamoto; Masahiro Goto; Wataru Tokuhara; Yoshiyuki Noritake; Satoshi Katahira; Nobuhiro Ishida; Kazunori Nakashima; Chiaki Ogino; Noriho Kamiya

    The potential of 1-buthyl-3-methylpyridinium chloride, [Bmpy][Cl], as a pretreatment solvent for lignocellulosic biomasses, Bagasse and Eucalyptus, was investigated. The yields of regenerated biomasses ranged between 35% and 96%, and varied according to the pretreatment time, type of ionic liquid (IL) and biomass. The pretreatment of the biomass with [Bmpy][Cl] resulted in up to 8-fold increase in the cellulose conversion when

  10. READINESS OF THE GULF MONETARY UNION: REVISITED

    Microsoft Academic Search

    Rock-Antoine Mehanna; M. Kabir Hassan

    2008-01-01

    This paper revisits Mehannas (2004) assessment of the viability of the future project of the Gulf Monetary Union (a goal set for 2010) while examining member countries over three time periods: (1) 1990-1999; (2) 2000-2006; and (3) average period 1990-2006. It follows the theory of Optimum Currency Areas and borrows from the European Monetary Union (the Maastricht Agreements convergence criteria)

  11. Short communication: Pharmacokinetics of intramammary hetacillin in dairy cattle milked 3 times per day.

    PubMed

    Lindquist, Danielle A; Baynes, Ronald E; Smith, Geof W

    2015-03-01

    Mastitis remains a critical disease in the dairy industry and the use of intramammary antibiotics plays a critical role in mastitis treatment. Hetacillin is currently approved as an intramammary antibiotic that is used to treat mastitis in dairy cows. It is approved for once a day administration and can be used for a total of 3 d. An increasing number of dairy farms are milking 3 times per day (instead of the traditional 2 times per day) and very little pharmacokinetic data exists on the use of intramammary drugs in a 3system. The primary purpose of this study was to determine if once a day intramammary infusion of hetacillin is sufficient to maintain therapeutic drug concentrations in cattle milked 3 times per day. Eight Holstein cattle milked 3 times per day were used in this study. After collecting a baseline milk sample, each cow received intramammary infusions of hetacillin in the left front and right rear quarters once a day for 3 d. Milk samples from each of the treated quarters were collected at each milking and frozen until analysis. Milk samples were analyzed for ampicillin concentrations using an ultra-performance liquid chromatography method. All treated quarters had antibiotic concentrations well above the minimum inhibitory concentration (MIC) for gram-positive mastitis pathogens at 8 and 16 h postinfusion. Milk concentrations had fallen well below the MIC by the 24-h period (before the next infusion). All 8 cows in this study consistently had individual quarter milk ampicillin concentrations below the FDA tolerance of 0.01 ?g/mL (10 ppb) within 48 h of the last infusion. Based on this study, milk ampicillin concentrations exceed the minimum inhibitory concentration required to inhibit the growth of 90% of organisms (MIC90) for at least 65% of the dosing interval, which is sufficient for once-daily dosing with most cases of gram-positive mastitis. Therefore, intramammary hetacillin should be an effective treatment for the vast majority of gram-positive mastitis pathogens when used according to label (once per day) in cows milked 3 times per day. PMID:25547305

  12. Empirical models of the eddy heat flux and vertical shear on short time scales

    NASA Technical Reports Server (NTRS)

    Ghan, S. J.

    1984-01-01

    An intimate relation exists between the vertical shear and the horizontal eddy heat flux within the atmosphere. In the present investigation empirical means are employed to provide clues concerning the relationship between the shear and eddy heat flux. In particular, linear regression models are applied to individual and joint time series of the shear and eddy heat flux. These discrete models are used as a basis to infer continuous models. A description is provided of the observed relationship between the flux and the shear, taking into account means, standard deviations, and lag correction functions.

  13. Short term effect of rainfall on suspected malaria episodes at Magaria, Niger: a time series study.

    PubMed

    Jusot, Jean-Franois; Alto, Oumarou

    2011-11-01

    Epidemiological patterns of malaria are influenced by different kinds of climate. In Sahelian countries, the link between climatic factors and malaria is still insufficiently quantified. The aim of this work was to conduct a time-series study of rainfall to estimate the increased risk of malaria morbidity. Daily suspected malaria episodes among subjects of all ages were collected retrospectively in three health care facilities between 1 January 2000 and 31 December 2003 at Magaria, Niger. These daily numbers were analysed with time-series methods, using generalized additive models with a negative binomial family. The impact of rainfall 40 days before occurrence of suspected malaria episodes was studied using a distributed lag model. More than 13 000 suspected malaria episodes were registered corresponding to an annual cumulative incidence rate of 7.4%. The overall excess risk of suspected malaria episodes for an increase of 1mm of rainfall after 40 days of exposure was estimated at 7.2%. This study allowed to specify the excess risk of rainfall on the occurrence of suspected malaria episodes in an intermediate rainfall area located in the Sahelian region in Niger. It was a first step to a health impact assessment. PMID:21925691

  14. High Photoresponsivity and Short Photoresponse Times in Few-Layered WSe2 Transistors.

    PubMed

    Pradhan, Nihar R; Ludwig, Jonathan; Lu, Zhengguang; Rhodes, Daniel; Bishop, Michael M; Thirunavukkuarasu, Komalavalli; McGill, Stephen A; Smirnov, Dmitry; Balicas, Luis

    2015-06-10

    Here, we report the photoconducting response of field-effect transistors based on three atomic layers of chemical vapor transport grown WSe2 crystals mechanically exfoliated onto SiO2. We find that trilayered WSe2 field-effect transistors, built with the simplest possible architecture, can display high hole mobilities ranging from 350 cm(2)/(V s) at room temperature (saturating at a value of ?500 cm(2)/(V s) below 50 K) displaying a strong photocurrent response, which leads to exceptionally high photoresponsivities up to 7 A/W under white light illumination of the entire channel for power densities p < 10(2) W/m(2). Under a fixed wavelength of ? = 532 nm and a laser spot size smaller than the conducting channel area, we extract photoresponsitivities approaching 100 mA/W with concomitantly high external quantum efficiencies up to ?40% at room temperature. These values surpass values recently reported from more complex architectures, such as graphene and transition metal dichalcogenides based heterostructures. Also, trilayered WSe2 phototransistors display photoresponse times on the order of 10 ?s. Our results indicate that the addition of a few atomic layers considerably decreases the photoresponse times, probably by minimizing the interaction with the substrates, while maintaining a very high photoresponsivity. PMID:25988364

  15. Synthesis of large scorodite particles using short period time sonication to enhance agglomeration of precursor

    NASA Astrophysics Data System (ADS)

    Kitamura, Yuya; Okawa, Hirokazu; Sugawara, Katsuyasu

    2015-07-01

    The effect of various sonication frequencies (28 kHz, 200 kHz, and 1.7 MHz) on the size of synthesized scorodite particles was investigated. First, the growth of the precursor with oxidation was observed in a synthesis process using stirring. The precursor size changed with the elapsed time and was <1 m at 0 min, approximately 1 m at 10 min, and >3 m at 20 min. The scorodite particles were then synthesized following different procedures such that a different size of the precursor was irradiated by each ultrasound frequency for 10 min during the oxidation process with stirring for a total duration of 180 min. For each frequency, the size of the synthesized particles varied depending on the size of the precursor. Large scorodite particles can be synthesized (70 C) by irradiating for only 30 min at various frequencies after the size of the precursor particles reaches the optimal range.

  16. Broadband extreme-ultraviolet survey spectrometer for short-time-scale experiments.

    PubMed

    Chapman, B E; Hartog, D J; Fonck, R J

    1994-07-01

    A fast and inexpensive spectrometer system has been developed to record extreme-UV impurity spectra in a magnetic-fusion-research device. To simplify the vacuum system, light is passed out of the spectrometer's vacuum to the detector with a sodium-salicylate-coated, fiber-optic coupler. This coupler is positioned so that the focal field is nearly flat over its aperture. The system's detector is a microchannelplate- intensified, linear, self-scanning photodiode array. The 1024-pixel array covers a bandwidth greater than 80 nm and is read out once every millisecond. The readout, which is four times faster than the manufacturer's maximum rating, is fully synchronized to the experiment by a locally designed control circuit. PMID:20935775

  17. Extracting Short Rise-Time Velocity Profiles with Digital Down-Shift Analysis of Optically Up-Converted PDV Data

    SciTech Connect

    Abel Diaz, Nathan Riley, Cenobio Gallegos, Matthew Teel, Michael Berninger, Thomas W. Tunnell

    2010-09-08

    This work describes the digital down-shift (DDS) technique, a new method of extracting short rise-time velocity profiles in the analysis of optically up-converted PDV data. The DDS technique manipulates the PDV data by subtracting a constant velocity (i.e., the DDS velocity ?DDS) from the velocity profile. DDS exploits the simple fact that the optically up-converted data ride on top of a base velocity (?0, the apparent velocity at no motion) with a rapid rise to a high velocity (?f) of a few km/s or more. Consequently, the frequency content of the signal must describe a velocity profile that increases from ?0 to ?0 + ?f. The DDS technique produces velocity reversals in the processed data before shock breakout when ?0 < ?DDS < ?0 + ?f. The DDS analysis process strategically selects specific DDS velocities (velocity at which the user down shifts the data) that produce anomalous reversals (maxima and/or minima), which are predictable and easy to identify in the mid-range of the data. Additional analysis determines when these maxima and minima occur. By successive application of the DDS technique and iterative analysis, velocity profiles are extracted as time as a function of velocity rather than as a function of time as it would be in a conventional velocity profile. Presented results include a description of DDS, velocity profiles extracted from laser-driven shock data with rise times of 200 ps or less, and a comparison with other techniques.

  18. On Short-Time Estimation of Vocal Tract Length from Formant Frequencies

    PubMed Central

    Lammert, Adam C.; Narayanan, Shrikanth S.

    2015-01-01

    Vocal tract length is highly variable across speakers and determines many aspects of the acoustic speech signal, making it an essential parameter to consider for explaining behavioral variability. A method for accurate estimation of vocal tract length from formant frequencies would afford normalization of interspeaker variability and facilitate acoustic comparisons across speakers. A framework for considering estimation methods is developed from the basic principles of vocal tract acoustics, and an estimation method is proposed that follows naturally from this framework. The proposed method is evaluated using acoustic characteristics of simulated vocal tracts ranging from 14 to 19 cm in length, as well as real-time magnetic resonance imaging data with synchronous audio from five speakers whose vocal tracts range from 14.5 to 18.0 cm in length. Evaluations show improvements in accuracy over previously proposed methods, with 0.631 and 1.277 cm root mean square error on simulated and human speech data, respectively. Empirical results show that the effectiveness of the proposed method is based on emphasizing higher formant frequencies, which seem less affected by speech articulation. Theoretical predictions of formant sensitivity reinforce this empirical finding. Moreover, theoretical insights are explained regarding the reason for differences in formant sensitivity. PMID:26177102

  19. Drop impact on a solid surface: short time self-similarity

    E-print Network

    Philippi, Julien; Antkowiak, Arnaud

    2015-01-01

    The early stages of drop impact onto a solid surface are considered. Detailed numerical simulations and detailed asymptotic analysis of the process reveal a self-similar structure both for the velocity field and the pressure field. The latter is shown to exhibit a maximum not near the impact point, but rather at the contact line. The motion of the contact line is furthermore shown to exhibit a 'tank treading' motion. These observations are apprehended at the light of a variant of Wagner theory for liquid impact. This framework offers a simple analogy where the fluid motion within the impacting drop may be viewed as the flow induced by a flat rising expanding disk. The theoretical predictions are found to be in very close agreement both qualitatively and quantitatively with the numerical observations for about three decades in time. Interestingly the inviscid self-similar impact pressure and velocities are shown to depend solely on the self-similar variables $(r/\\sqrt{t},z/\\sqrt{t})$. The structure of the boun...

  20. Estimation of coupling between oscillators from short time series via phase dynamics modeling: limitations and application to EEG data.

    PubMed

    Smirnov, D A; Bodrov, M B; Velazquez, J L Perez; Wennberg, R A; Bezruchko, B P

    2005-06-01

    We demonstrate in numerical experiments that estimators of strength and directionality of coupling between oscillators based on modeling of their phase dynamics [D. A. Smirnov and B. P. Bezruchko, Phys. Rev. E 68, 046209 (2003)] are widely applicable. Namely, although the expressions for the estimators and their confidence bands are derived for linear uncoupled oscillators under the influence of independent sources of Gaussian white noise, they turn out to allow reliable characterization of coupling from relatively short time series for different properties of noise, significant phase nonlinearity of the oscillators, and nonvanishing coupling between them. We apply the estimators to analyze a two-channel human intracranial epileptic electroencephalogram (EEG) recording with the purpose of epileptic focus localization. PMID:16035902

  1. An Evaluation of Some Current Practices for Short-Time Elevated-Temperature Tensile Tests of Metals

    NASA Technical Reports Server (NTRS)

    Manning, Charles R., Jr.; Heimerl, George J.

    1960-01-01

    The effect of different testing practices on the short-time elevated-temperature tensile properties was determined for 2024-T3 aluminum-alloy, HM21A-T8 and HK31A-H24 magnesium-alloy, and 12 MoV stainless-steel sheet. Tests were made under single strain-rate and single head-speed conditions. A dual strain-rate test was also included. An evaluation of the effects of these practices is given for the tensile and yield strengths, the elongation in 2 inches, and the uniform elongation. The need for a uniform testing practice is demonstrated. Recommended practices suggested by different organizations are included.

  2. Static Network Code DGPS Positioning vs. Carrier Phase Single Baseline Solutions for Short Observation Time and Medium-Long Distances

    NASA Astrophysics Data System (ADS)

    Baku?a, M.

    GPS land surveys are usually based on the results of processing GPS carrier phase data. Code or pseudorange observations due to considerations of accuracy requirements and robustness are preferred in navigation and some GIS applications. Generally, the accuracy of that positioning is in the range of about 1-2meters or so, on average. But the main problem in code GPS positioning is to know how to estimate the real accuracy of DGPS positions. It is not such an easy process in code positioning when one reference station is used. In most commercial software, there are no values of accuracy but only positions are presented. DGPS positions without estimated errors cannot be used for surveying tasks and for most GIS applications due to the fact that every point has to have accuracy determined. However, when using static GPS positioning, it is well known that the accuracy is determined, both during baseline processing and next by the adjustment of a GPS network. These steps of validation with redundancy in classical static phase baseline solutions allow wide use of static or rapid static methods in the main land surveying tasks. Although these control steps are commonly used in many major surveying and engineering tasks, they are not always effective in terms of short-observation-time sessions. This paper presents a new network DGPS approach of positioning with the use of at least three reference stations. The approach concerns also valid accuracy estimation based on variance-covariance matrix in the least-squares calculations. The presented network DGPS approach has the ability of reliable accuracy estimation. Finally, network DGPS positioning is compared with static baselines solutions where five-min sessions were taken into consideration for two different rover stations. It was shown that in a short observation time of GPS positioning, code network DGPS results can give even centimetre accuracy and can be more reliable than static relative phase positioning where gross errors often happen.

  3. Quantifying cortical bone water in vivo by three-dimensional ultra-short echo-time MRI

    PubMed Central

    Rad, Hamidreza Saligheh; Lam, Shing Chun Benny; Magland, Jeremy F.; Ong, Henry; Li, Cheng; Song, Hee Kwon; Love, James; Wehrli, Felix W.

    2013-01-01

    Bone contains a significant fraction of water that is not detectable with ordinary Cartesian imaging sequences. The advent of ultra-short echo-time (UTE) methods has allowed the recovery of this submillisecond T2*water. In this work, we have developed a new three-dimensional hybrid-radial ultra-short echo-time (3D HRUTE) imaging technique based on slab selection by means of half-sinc pulses, variable-TE slice encoding and algorithms for quantification. The protocol consists of collecting two datasets differing in TR, from which T1 is extracted, which is needed for quantification. Unlike T2*, which has been found to vary within a narrow range and does not require individual correction, T1 is critically subject dependent (range, 100350 ms). No soft-tissue suppression was used to preserve the signal-to-noise ratio of the short-T2 bone water protons or to minimize the loss of relatively mobile water in large pores. Critical for quantification is correction for spatial variations in reception field and selection of the endosteal boundary for inclusion of pixels in the bone water calculation, because of the ruffled boundary stemming from trabecularization of the endosteal surface. The reproducibility, evaluated in 10 subjects covering the age range 3080 years, yielded an average coefficient of variation of 4.2% and an intraclass correlation coefficient of 0.95, suggesting that a treatment effect on the order of 5% could be detected in as few as 10 subjects. Lastly, experiments in specimens by means of graded deuterium exchange showed that approximately 90% of the detected signal arises from water protons, whose relaxation rates (1/T1 and 1/T2*) scale linearly with the isotopic volume fraction of light water after stepwise exchange with heavy water. The data thus show conclusively that the method quantifies water even though, in vivo, no distinction can be made between various fractions, such as collagen-bound vs pore-resident water. PMID:21274960

  4. Time-Resolved Spectroscopy of the 3 Brightest and Hardest Short Gamma-Ray Bursts Observed with the FGST Gamma-Ray Burst Monitor

    E-print Network

    Guiriec, Sylvain; Connaugthon, Valerie; Kara, Erin; Daigne, Frederic; Kouveliotou, Chryssa; van der Horst, Alexander J; Paciesas, William; Meegan, Charles A; Bhat, P N; Foley, Suzanne; Bissaldi, Elisabetta; Burgess, Michael; Chaplin, Vandiver; Diehl, Roland; Fishman, Gerald; Gibby, Melissa; Giles, Misty; Goldstein, Adam; Greiner, Jochen; Gruber, David; von Kienlin, Andreas; Kippen, Marc; McBreen, Sheila; Preece, Robert; Rau, Arne; Tierney, Dave; Wilson-Hodge, Colleen

    2010-01-01

    From July 2008 to October 2009, the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope (FGST) has detected 320 Gamma-Ray Bursts (GRBs). About 20% of these events are classified as short based on their T90 duration below 2 s. We present here for the first time time-resolved spectroscopy at timescales as short as 2 ms for the three brightest short GRBs observed with GBM. The time-integrated spectra of the events deviate from the Band function, indicating the existence of an additional spectral component, which can be fit by a power-law with index ~-1.5. The time-integrated Epeak values exceed 2 MeV for two of the bursts, and are well above the values observed in the brightest long GRBs. Their Epeak values and their low-energy power-law indices ({\\alpha}) confirm that short GRBs are harder than long ones. We find that short GRBs are very similar to long ones, but with light curves contracted in time and with harder spectra stretched towards higher energies. In our time-resolved spectrosco...

  5. Acetylcholine measured at short time intervals during transmission of nerve impulses in the electric organ of Torpedo

    PubMed Central

    Dunant, Y.; Jones, G. J.; Loctin, Franoise

    1982-01-01

    1. The amounts of total acetylcholine (ACh) and ATP, and of vesicle-bound ACh were measured at short time intervals in the electrogenic tissue of Torpedo marmorata. The aim of this study is to approach with biochemical analysis the speed of electrophysiological phenomena. 2. A stimulator coupled to a rapid freezer device was used to quench a number of tissue samples simultaneously, at different time intervals during transmission of a brief train of impulses at 100 Hz. 3. The level of total ACh decreased significantly with the first ten impulses. Then a rapid but transient increase in total ACh occurred, reaching a maximum value by the fifteenth to sixteenth impulse. 4. Vesicle-bound ACh did not exhibit any changes parallel to those of total ACh, and did not decrease beyond the control level during transmission of twenty impulses at 100 Hz. 5. The amount of ATP in the tissue varied in close relation to that of total ACh. No significant phase shift was observed between the transmitter and the nucleotide and the ACh/ATP molar ratio was not significantly different from 1. 6. The shortest time interval investigated in this work was 10 ms. The rate at which the pieces of tissue are quenched for biochemical measurements when plunged into a liquid at low temperature has been estimated. It has also been evaluated to what extent the freezing rate may distort measurements of the biochemical changes occurring in the tissue. 7. It is concluded that fast freezing appears to be a valuable approach for investigating the rapid biochemical changes underlying cholinergic transmission; a better time resolution might be reached at the price, however, of greatly reducing the size of the samples. The second conclusion is that transmission of a brief train of impulses is accompanied by significant changes in the amount of extravesicular ACh. PMID:6286941

  6. Short UV luminescence for forensic applications: design of a real-time observation system for detection of latent fingerprints and body fluids.

    PubMed

    Ben Yosef, N; Almog, J; Frank, A; Springer, E; Cantu, A A

    1998-03-01

    An assembly that allows a pseudo real-time (one second delay) observation of latent fingerprints by their short ultraviolet luminescence was designed. It is composed of a mercury-xenon lamp and a CCD camera, both water-cooled and computer-controlled. The system is used to study the behaviour of latent fingerprints and stains of body fluids such as blood, semen and saliva under short-UV illumination. PMID:9544537

  7. Abnormally Short Activated Partial Thromboplastin Times Are Related to Elevated Plasma Levels of TAT, F1+2, D-Dimer and FVIII:C

    Microsoft Academic Search

    Edwin ten Boekel; Piet Bartels

    2002-01-01

    Abnormally short activated partial thromboplastin times (APTTs) are associated with an increased risk of thrombotic disorders. We have examined the status of coagulation activity in subjects with short APTTs. In addition, the presence of the thrombotic risk factors G1691A-factor V, G20210A-prothrombin gene mutation and factor VIII coagulant activity (FVIII:C) was determined. Plasma levels of TAT, F1+2, D-dimer and FVIII:C were

  8. A Bayesian method for characterizing distributed micro-releases: II. inference under model uncertainty with short time-series data.

    SciTech Connect

    Marzouk, Youssef; Fast P. (Lawrence Livermore National Laboratory, Livermore, CA); Kraus, M. (Peterson AFB, CO); Ray, J. P.

    2006-01-01

    Terrorist attacks using an aerosolized pathogen preparation have gained credibility as a national security concern after the anthrax attacks of 2001. The ability to characterize such attacks, i.e., to estimate the number of people infected, the time of infection, and the average dose received, is important when planning a medical response. We address this question of characterization by formulating a Bayesian inverse problem predicated on a short time-series of diagnosed patients exhibiting symptoms. To be of relevance to response planning, we limit ourselves to 3-5 days of data. In tests performed with anthrax as the pathogen, we find that these data are usually sufficient, especially if the model of the outbreak used in the inverse problem is an accurate one. In some cases the scarcity of data may initially support outbreak characterizations at odds with the true one, but with sufficient data the correct inferences are recovered; in other words, the inverse problem posed and its solution methodology are consistent. We also explore the effect of model error-situations for which the model used in the inverse problem is only a partially accurate representation of the outbreak; here, the model predictions and the observations differ by more than a random noise. We find that while there is a consistent discrepancy between the inferred and the true characterizations, they are also close enough to be of relevance when planning a response.

  9. Mi-1-Mediated Nematode Resistance in Tomatoes is Broken by Short-Term Heat Stress but Recovers Over Time.

    PubMed

    Marques de Carvalho, Luciana; Benda, Nicole D; Vaughan, Martha M; Cabrera, Ana R; Hung, Kaddie; Cox, Thomas; Abdo, Zaid; Allen, L Hartwell; Teal, Peter E A

    2015-06-01

    Tomato (Solanum lycopersicum L.) is among the most valuable agricultural products, but Meloidogyne spp. (root-knot nematode) infestations result in serious crop losses. In tomato, resistance to root-knot nematodes is controlled by the gene Mi-1, but heat stress interferes with Mi-1-associated resistance. Inconsistent results in published field and greenhouse experiments led us to test the effect of short-term midday heat stress on tomato susceptibility to Meloidogyne incognita race 1. Under controlled day/night temperatures of 25C/21C, 'Amelia', which was verified as possessing the Mi-1 gene, was deemed resistant (4.1 0.4 galls/plant) and Rutgers, which does not possess the Mi-1 gene, was susceptible (132 9.9 galls/plant) to M. incognita infection. Exposure to a single 3 hr heat spike of 35C was sufficient to increase the susceptibility of 'Amelia' but did not affect Rutgers. Despite this change in resistance, Mi-1 gene expression was not affected by heat treatment, or nematode infection. The heat-induced breakdown of Mi-1 resistance in 'Amelia' did recover with time regardless of additional heat exposures and M. incognita infection. These findings would aid in the development of management strategies to protect the tomato crop at times of heightened M. incognita susceptibility. PMID:26170475

  10. Improvements in localized proton NMR spectroscopy of human brain. Water suppression, short echo times, and 1 ml resolution

    NASA Astrophysics Data System (ADS)

    Frahm, J.; Michaelis, T.; Merboldt, K. D.; Bruhn, H.; Gyngell, M. L.; Hnicke, W.

    Considerable technical improvements are reported for localized proton NMR spectroscopy using stimulated echoes. When compared to previous results, proton NMR spectra of the human brain are now obtainable (i) with in vivo water suppression factors of ?1000, (ii) with only minor T2 losses and negligible distortions due to J modulation at short echo times of 10-20 ms, and (iii) from volumes of interest as small as 1-8 ml within measuring times of 1-10 min. As a consequence, the detection of cerebral metabolites is greatly facilitated. This particularly applies to the assignment of those resonances (e.g., glutamate, taurine, inositols) that suffer from strong spin-spin coupling at the field strengths commonly in use for NMR in man. Studies of regional metabolite differences, tissue heterogeneity, and focal lesions in patients benefit from the increased spatial resolution and a concomitant reduction of partial volume effects. Localized proton NMR spectroscopy was performed on young healthy volunteers. Experiments were carried out on a 2.0 T whole-body MRI/MRS system using the standard headcoil for both imaging and spectroscopy.

  11. Mi-1-Mediated Nematode Resistance in Tomatoes is Broken by Short-Term Heat Stress but Recovers Over Time

    PubMed Central

    Marques de Carvalho, Luciana; Benda, Nicole D.; Vaughan, Martha M.; Cabrera, Ana R.; Hung, Kaddie; Cox, Thomas; Abdo, Zaid; Allen, L. Hartwell; Teal, Peter E. A.

    2015-01-01

    Tomato (Solanum lycopersicum L.) is among the most valuable agricultural products, but Meloidogyne spp. (root-knot nematode) infestations result in serious crop losses. In tomato, resistance to root-knot nematodes is controlled by the gene Mi-1, but heat stress interferes with Mi-1-associated resistance. Inconsistent results in published field and greenhouse experiments led us to test the effect of short-term midday heat stress on tomato susceptibility to Meloidogyne incognita race 1. Under controlled day/night temperatures of 25C/21C, Amelia, which was verified as possessing the Mi-1 gene, was deemed resistant (4.1 0.4 galls/plant) and Rutgers, which does not possess the Mi-1 gene, was susceptible (132 9.9 galls/plant) to M. incognita infection. Exposure to a single 3 hr heat spike of 35C was sufficient to increase the susceptibility of Amelia but did not affect Rutgers. Despite this change in resistance, Mi-1 gene expression was not affected by heat treatment, or nematode infection. The heat-induced breakdown of Mi-1 resistance in Amelia did recover with time regardless of additional heat exposures and M. incognita infection. These findings would aid in the development of management strategies to protect the tomato crop at times of heightened M. incognita susceptibility.

  12. Electrocardiogram Signal and Linear Time-Frequency Transforms

    NASA Astrophysics Data System (ADS)

    Krishna, B. T.

    2014-12-01

    The diagnostic analysis of non-stationary multi component signals such as electrocardiogram (ECG) involves the use of time-frequency transforms. So, the application of time-frequency transforms to an ECG signal is an important problem of research. In this paper, initially, linear transforms like short time Fourier transform, continuous wavelet transforms, s-transform etc. are revisited. Then the application of these transforms to normal and abnormal ECG signals is illustrated. It has been observed that s-transform provides better time and frequency resolution compared to other linear transforms. The fractional Fourier transform provides rotation to the spectrogram representation.

  13. 1558 PROCEEDINGS OF THE IEEE,VOL. 65, NO.11, NOVEMBER 1977 A Unified Approach to Short-Time Fourier Analysis

    E-print Network

    Allen, Jont

    , and to show the effects of modifying the short-time Fourier transform on the resulting signal. 11 the filter-bank armmation (FBS) method and the O V ~ - lap add (OM)method Each of these synthesist a u(possiMy signal dependent) to theshort-time Fowkr tnnsfcam is dao disc& Fi- d y it is shown that a f d

  14. Investigating the nonlinear dynamics of cellular motion in the inner ear using the short-time Fourier and continuous wavelet transforms

    Microsoft Academic Search

    Conor Heneghan; Shyam M. Khanna; Ake Flock; Mats Ulfendahl; Lou Brundin; Malvin C. Teich

    1994-01-01

    The short-time Fourier transform (STFT) and the continuous wavelet transform (CWT) are used to analyze the time course of cellular motion in the inner ear. The velocity responses of individual outer hair cells and Hensen's cells to sinusoidal and amplitude modulated (AM) acoustical signals applied at the ear canal display characteristics typical of nonlinear systems, including the generation of harmonic

  15. Figure 1.13. Einstein's locally special relativity principle: where-ever we drop a small enough spaceship, for a short enough time it will experience special relativity.

    E-print Network

    32 Figure 1.13. Einstein's locally special relativity principle: where-ever we drop a small enough spaceship, for a short enough time it will experience special relativity. 4.2 Space-time in general relativity Next we implement Einstein's locally special relativity principle (for- mulated in subsection 4

  16. High-Temperature Short-Time Sterilized Evaporated Milk. III. The Influence of the Lipid Phase on Heat and Storage Stability

    Microsoft Academic Search

    Abraham Leviton; Michael J. Pallansch

    1961-01-01

    SUMMARY Laboratory experiments in which high temperature-short time sterilization of con- centrated milk was carried out under static conditions showed that heat and storage stability were at times adversely affected by the presence of a lipid phase. Three types of milk were encountered. The predominant type (if forewarming was employed) con- sisted of milks in which the fat phase behaved

  17. Radiolytic Cryovolcanism Revisited

    NASA Astrophysics Data System (ADS)

    Cooper, J. F.; Cooper, P. D.; Sittler, E. C.; Wesenberg, R. P.

    2013-12-01

    Active geysers of water vapor and ice grains from the south pole of Enceladus are not yet definitively explained in terms of energy sources and processes. Other instances of hot (Io) and cold (Mars, Triton) volcanism beyond Earth are known if not fully understood. We revisit, in comparison to other models, the 'Old Faithful' theory of radiolytic gas-driven cryovolcanism first proposed by Cooper et al. [Plan. Sp. Sci. 2009]. In the energetic electron irradiation environment of Enceladus within Saturn's magnetosphere, a 10-percent duty cycle could be maintained for current geyser activity driven by gases from oxidation of ammonia to N2 and methane to CO2 in the thermal margins of a south polar sea. Much shorter duty cycles down to 0.01 percent would be required to account for thermal power output up to 16 GW, Steady accumulation of oxidant energy over four billion years could have powered all Enceladus emissions over the past four hundred thousand to four hundred million years. There could be separate energy sources driving mass flow and thermal emission over vastly different time scales. Since episodic tidal dissipation on 10 Myr time scales at 0.1 - 1 Gyr intervals [O'Neill and Nimmo, Nature 2010], and thus duty cycles 1 - 10 percent, could heat the polar sea to the current level, the radiolytic energy source could easily power and modulate the geyser mass flow on million-year time scales. Maximum thermal emission temperature 223 K [Abramov and Spencer, Icarus 2009] hints at thermal buffering in the basal and vent wall layers by a 1:1 H2O:H2O2 radiolytic eutectic, assuming deep ice crust saturation with H2O2 from long cumulative surface irradiation and downward ice convection. Due to density stratification the peroxide eutectic and salt water layers could separate, so that the denser peroxide layer (1.2 g/cc) descends to the polar sea while the lighter salt water (1.05 g/cc) rises along separate channels. Methane reservoirs could be found dissolved into the polar sea, or else trapped in hydrates [Kieffer et al., Science 2006] along flow paths and at the walls of the polar sea at surface depths below 20 km [Fortes, Icarus 2007]. Driver gas production for cryovolcanism could occur wherever these two layers come into contact under requisite temperature and pressure conditions, e.g. from 220 K and 10 bar at the 10-km basal layer of the overlying ice crust to 647 K and 220 bars at the liquid water limit, above the core-mantle boundary at 460 bars [Fortes, Icarus 2007]. We expect H2O2 oxidation to ignite at high temperatures but metallic minerals could catalyze reactions at lower temperatures nearer the basal layer. Pressure effects on oxidation rates are uncertain. Definitive modeling of Enceladus cryovolcanism likely involves synthesis of key processes from multiple models: Cold Faithful [Porco et al., Science 2006], Frigid Faithful [Keiffer et al., Science 2006], Frothy Faithful [Fortes, Icarus 2007], Old Faithful, and 'Perrier Ocean' recirculation [Matson et al., Icarus 2012].

  18. Thermal inactivation of foot-and-mouth disease virus in milk using high-temperature, short-time pasteurization.

    PubMed

    Tomasula, P M; Kozempel, M F; Konstance, R P; Gregg, D; Boettcher, S; Baxt, B; Rodriguez, L L

    2007-07-01

    Previous studies of laboratory simulation of high temperature, short time pasteurization (HTST) to eliminate foot-and-mouth disease virus (FMDV) in milk have shown that the virus is not completely inactivated at the legal pasteurization minimum (71.7 degrees C/15 s) but is inactivated in a flow apparatus at 148 degrees C with holding times of 2 to 3 s. It was the intent of this study to determine whether HTST pasteurization conducted in a continuous-flow pasteurizer that simulates commercial operation would enhance FMDV inactivation in milk. Cows were inoculated in the mammary gland with the field strain of FMDV (01/UK). Infected raw whole milk and 2% milk were then pasteurized using an Arm-field pilot-scale, continuous-flow HTST pasteurizer equipped with a plate-and-frame heat exchanger and a holding tube. The milk samples, containing FMDV at levels of up to 10(4) plaque-forming units/mL, were pasteurized at temperatures ranging from 72 to 95 degrees C at holding times of either 18.6 or 36 s. Pasteurization decreased virus infectivity by 4 log10 to undetectable levels in tissue culture. However, residual infectivity was still detectable for selected pasteurized milk samples, as shown by intramuscular and intradermal inoculation of milk into nave steers. Although HTST pasteurization did not completely inactivate viral infectivity in whole and 2% milk, possibly because a fraction of the virus was protected by the milk fat and the casein proteins, it greatly reduced the risk of natural transmission of FMDV by milk. PMID:17582103

  19. Mission Design and Analysis for Suborbital Intercept and Fragmentation of an Asteroid with Very Short Warning Time

    NASA Technical Reports Server (NTRS)

    Hupp, Ryan; DeWald, Spencer; Wie, Bong; Barbee, Brent W.

    2014-01-01

    Small near-Earth objects (NEOs) approximately 50-150 m in size are far more numerous (hundreds of thousands to millions yet to be discovered) than larger NEOs. Small NEOs, which are mostly asteroids rather than comets, are very faint in the night sky due to their small sizes, and are, therefore, difficult to discover far in advance of Earth impact. Furthermore, even small NEOs are capable of creating explosions with energies on the order of tens or hundreds of megatons (Mt). We are, therefore, motivated to prepare to respond effectively to short warning time, small NEO impact scenarios. In this paper we explore the lower bound on actionable warning time by investigating the performance of notional upgraded Intercontinental Ballistic Missiles (ICBMs) to carry Nuclear Explosive Device (NED) payloads to intercept and disrupt a hypothetical incoming NEO at high altitudes (generally at least 2500 km above Earth). We conduct this investigation by developing optimal NEO intercept trajectories for a range of cases and comparing their performances. Our results show that suborbital NEO intercepts using Minuteman III or SM-3 IIA launch vehicles could achieve NEO intercept a few minutes prior to when the NEO would strike Earth. We also find that more powerful versions of the launch vehicles (e.g., total delta V of approximately 9.5-11 km/s) could intercept incoming NEOs several hours prior to when the NEO would strike Earth, if launched at least several days prior to the time of intercept. Finally, we discuss a number of limiting factors and practicalities that affect whether the notional systems we describe could become feasible.

  20. Dose-dependency and time-course of electrophysiologic short-term effects of VIAGRA: a case study.

    PubMed

    Jgle, Herbert; Jgle, Christine; Srey, Ludwig; Sharpe, Lindsay T

    2005-01-01

    The dose-dependency and time-course of the short-term visual effects of sildenafil citrate (VIAGRA) were tested in two subjects. Blood pressure was measured and samples of blood taken at 30 min intervals before and after drug administration. In the first experiment, prolongations of the implicit times of the scotopic maximum a-wave, cone a- and b-wave, 33 Hz flicker, ON-response a- and b-wave and 3.3 Hz a- and b-wave electroretinogram (ERG) recordings and of the oscillatory potentials OP1, OP2, and OP3 were observed for both eyes of both subjects, following 100 or 200 mg dosings. Interestingly, no prolongation was found for OP4, to which the OFF-bipolar cell pathway significantly contributes. In the second experiment, in which visual function was repeatedly assessed following a 200 mg dose, similar prolongations were found in both eyes of one subject for the implicit times of the oscillatory potential OP2, the cone b-wave response and the 3.3 Hz a-wave. Moreover, the steady-state (A0) and immediate extinction (B0) blue target thresholds of transient tritanopia were raised relative to the pre-drug administration baseline effects. While the maximum lowering of both systolic and diastolic blood pressure approximately correlated with the peak plasma concentration of sildenafil (c. 30-60 min after administration), the peak magnitudes of most visual effects were found at c. 110 min, consistent with a second compartment kinetic. PMID:16328933

  1. Treatment of Fungal Bioaerosols by a High-Temperature, Short-Time Process in a Continuous-Flow System?

    PubMed Central

    Jung, Jae Hee; Lee, Jung Eun; Lee, Chang Ho; Kim, Sang Soo; Lee, Byung Uk

    2009-01-01

    Airborne fungi, termed fungal bioaerosols, have received attention due to the association with public health problems and the effects on living organisms in nature. There are growing concerns that fungal bioaerosols are relevant to the occurrence of allergies, opportunistic diseases in hospitals, and outbreaks of plant diseases. The search for ways of preventing and curing the harmful effects of fungal bioaerosols has created a high demand for the study and development of an efficient method of controlling bioaerosols. However, almost all modern microbiological studies and theories have focused on microorganisms in liquid and solid phases. We investigated the thermal heating effects on fungal bioaerosols in a continuous-flow environment. Although the thermal heating process has long been a traditional method of controlling microorganisms, the effect of a continuous high-temperature, short-time (HTST) process on airborne microorganisms has not been quantitatively investigated in terms of various aerosol properties. Our experimental results show that the geometric mean diameter of the tested fungal bioaerosols decreased when they were exposed to increases in the surrounding temperature. The HTST process produced a significant decline in the (1?3)-?-d-glucan concentration of fungal bioaerosols. More than 99% of the Aspergillus versicolor and Cladosporium cladosporioides bioaerosols lost their culturability in about 0.2 s when the surrounding temperature exceeded 350C and 400C, respectively. The instantaneous exposure to high temperature significantly changed the surface morphology of the fungal bioaerosols. PMID:19201954

  2. Short-term light adaptation of a cyanobacterium, Synechocystis sp. PCC 6803, probed by time-resolved fluorescence spectroscopy.

    PubMed

    Akimoto, Seiji; Yokono, Makio; Yokono, Erina; Aikawa, Shimpei; Kondo, Akihiko

    2014-08-01

    In photosynthetic organisms, the interactions among pigment-protein complexes change in response to light conditions. In the present study, we analyzed the transfer of excitation energy from the phycobilisome (PBS) and photosystem (PS) II to PSI in the cyanobacterium Synechocystis sp. PCC 6803. After 20min of dark adaptation, Synechocystis cells were illuminated for 5min with strong light with different spectral profiles, blue, green, two kinds of red, and white light. After illumination, the energy-transfer characteristics were evaluated using steady-state fluorescence and picosecond time-resolved fluorescence spectroscopy techniques. The fluorescence rise and decay curves were analyzed by global analysis to obtain fluorescence decay-associated spectra, followed by spectral component analysis. Under illumination with strong light, the contribution of the energy transfer from the PSII to PSI (spillover) became greater, and that of the energy transfer from the PBS to PSI decreased; the former change was larger than the latter. The energy transfer pathway to PSI was sensitive to red light. We discuss the short-term adaptation of energy-transfer processes in Synechocystis under strong-light conditions. PMID:24495908

  3. Assessing short- and long-time displacements in the Venice coastland by synthetic aperture radar interferometric point target analysis

    NASA Astrophysics Data System (ADS)

    Teatini, Pietro; Strozzi, Tazio; Tosi, Luigi; Wegmller, Urs; Werner, Charles; Carbognin, Laura

    2007-03-01

    The Venice Lagoon in Italy is a unique environment vulnerable to loss in surface elevation relative to the mean sea level. We present detailed synthetic aperture radar (SAR) interferometric analyses on persistent point targets for the historical center of Venice, the tourist area of Sottomarina, and the Zennare farmland close to the southern lagoon edge. The selected areas are characterized by different degrees of development and our analyses show the remarkable capability of SAR Interferometric Point Target Analysis (IPTA) to map land displacement rates in densely urbanized zones and to detect movement information on isolated structures with a mm/year accuracy. A detailed analysis of the time series from 1992 to 2000 provided by IPTA shows that the vertical component of the measured displacements are the superposition of a short timescale, generally seasonal, movement on the order of 1 cm that is likely related to the fluctuation of environmental variables (temperature, piezometric head in the aquifer system underlying the lagoon, sea/lagoon water level) and a long-term ground deformation associated with building construction, the geomorphology of the area, and the human development of natural resources. If Venice is confirmed to be generally stable, significant long-term subsidence on the order of 4 mm/year is detected at the Sottomarina coastland. The highest displacement rates, of up to 8-10 mm/year, are recorded in the farmland bounding the lagoon margin where the movements are found to be highly site-specific.

  4. Low-Frequency Spectra of Amino Acids and Short-Chain Peptides Studied by Terahertz Time-Domain Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ponseca, Carlito S.; Kambara, Ohki; Kawaguchi, Shintaro; Yamamoto, Kohji; Tominaga, Keisuke

    2010-07-01

    The low-frequency spectra of the amino acids l-alanine and glycine and their peptides were studied using terahertz (THz) time-domain spectroscopy (TDS) at room temperature. In a previous work (Yamamoto et al., Biophys. J. 89, L22-L24 (2005)), the low-frequency spectra of amino acids (glycine and l-alanine) and their polypeptides (polyglycine and poly- l-alanine) were studied by THz-TDS, and it was found that there is a clear difference in low-frequency dynamics between the amino acids and the polypeptides. In the present study, amino acids and short peptides were chosen in order to investigate the effect of polymerization on low-frequency spectra. We focus on two physical quantities to represent the spectral features: (1) the intensity of the reduced absorption cross section (RACS), which we define from the absorption coefficient and refractive index, and (2) the exponent in the power law behavior of the RACS. We found that the two physical quantities show different dependences on peptide chain length, suggesting that the two physical quantities reflect different dynamics and interactions. The change in RACS intensity may be due to intermolecular or intrachain motion. The validity of the assumption of constant IR activity in the investigated frequency region is critical to understanding the origin of the variation in the exponent with chain length.

  5. Short Repetition Time Multiband Echo-Planar Imaging with Simultaneous Pulse Recording Allows Dynamic Imaging of the Cardiac Pulsation Signal

    PubMed Central

    Tong, Yunjie; Hocke, Lia M.; Frederick, Blaise deB.

    2014-01-01

    Purpose Recently developed simultaneous multislice echoplanar imaging (EPI) sequences permit imaging of the whole brain at short repetition time (TR), allowing the cardiac fluctuations to be fully sampled in blood-oxygen-level dependent functional MRI (BOLD fMRI). A novel low computational analytical method was developed to dynamically map the passage of the pulsation signal through the brain and visualize the whole cerebral vasculature affected by the pulse signal. This algorithm is based on a simple combination of fast BOLD fMRI and the scanner's own built-in pulse oximeter. Methods Multiple, temporally shifted copies of the pulse oximeter data (with 0.08 s shifting step and coverage of a 1-s span) were downsampled and used as cardiac pulsation regressors in a general linear model based analyses (FSL) of the fMRI data. The resulting concatenated z-statistics maps show the voxels that are affected as the cardiac signal travels through the brain. Results Many voxels were highly correlated with the pulsation regressor or its temporally shifted version. The dynamic and static cardiac pulsation maps obtained from both the task and resting state scans, resembled cerebral vasculature. Conclusion The results demonstrated: (i) cardiac pulsation significantly affects most voxels in the brain; (ii) combining fast fMRI and this analytical method can reveal additional clinical information to functional studies. PMID:24272768

  6. Regulation of the timing of MNTB neurons by short-term and long-term modulation of potassium channels.

    PubMed

    Kaczmarek, Leonard K; Bhattacharjee, Arin; Desai, Rooma; Gan, Li; Song, Ping; von Hehn, Christian A A; Whim, Matthew D; Yang, Bo

    2005-08-01

    The firing patterns of neurons in central auditory pathways encode specific features of sound stimuli, such as frequency, intensity and localization in space. The generation of the appropriate pattern depends, to a major extent, on the properties of the voltage-dependent potassium channels in these neurons. The mammalian auditory pathways that compute the direction of a sound source are located in the brainstem and include the connection from bushy cells in the anteroventral cochlear nucleus (AVCN) to the principal neurons of the medial nucleus of the trapezoid body (MNTB). To preserve the fidelity of timing of action potentials that is required for sound localization, these neurons express several types of potassium channels, including the Kv3 and Kv1 families of voltage-dependent channels and the Slick and Slack sodium-dependent channels. These channels determine the pattern of action potentials and the amount of neurotransmitter released during repeated stimulation. The amplitude of currents carried by one of these channels, the Kv3.1b channel, is regulated in the short term by protein phosphorylation, and in the long term, by changes in gene expression, such that the intrinsic excitability of the neurons is constantly being regulated by the ambient auditory environment. PMID:16081004

  7. Short time-scale AGN X-ray variability with EXOSAT: black hole mass and normalized variability amplitude

    NASA Astrophysics Data System (ADS)

    McHardy, I. M.

    2013-03-01

    The old EXOSAT medium energy measurements of high-frequency (HF) active galactic nuclei (AGN) power spectral normalization are re-examined in the light of accurate black hole mass determinations which were not available when these data were first published by Green et al. It is found that the normalized variability amplitude (NVA), measured directly from the power spectrum, is proportional to M?, where ? -0.54 0.08. As NVA is the square root of the power, these observations show that the normalization of the HF power spectrum for this sample of AGN varies very close to inversely with black hole mass. Almost the same value of ? is obtained whether the quasar 3C 273 is included in the sample or not, suggesting that the same process that drives X-ray variability in Seyfert galaxies applies also to 3C 273. These observations support the work of Gierli?ski et al. who show that an almost exactly linear anticorrelation is required if the normalizations of the HF power spectra of AGN and X-ray binary systems are to scale similarly. These observations are also consistent with a number of studies showing that the short time-scale variance of AGN X-ray light curves varies approximately inversely with mass.

  8. In vitro short-time killing activity of povidone-iodine (Isodine Gargle) in the presence of oral organic matter.

    PubMed

    Yoneyama, Akiko; Shimizu, Masaki; Tabata, Makiko; Yashiro, Junko; Takata, Toshihiko; Hikida, Muneo

    2006-01-01

    In order to estimate the clinical efficacy of a povidone-iodine oral antiseptic (PVP-I) on oral bacterial infectious diseases, we studied the effect of oral organic matter on the in vitro killing activity of PVP-I. In addition, we compared the in vitro short-time killing activity of PVP-I with those of other oral antiseptics using mouth-washing and gargling samples collected from healthy volunteers. When any of the mouth-washing and gargling samples was used, the standard (0.23-0.47%) or lower concentrations of PVP-I killed methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, including multidrug-resistant strains, within 15-60 s in the presence of oral organic matter. 0.02% benzethonium chloride (BEC) and 0.002% chlorhexidine gluconate (CHG) did not show effects against MRSA and P. aeruginosa (including multidrug-resistant strains) in mouth-washing and gargling samples even after 60 s. The above-mentioned results show that the in vitro killing activity of the standard concentration of PVP-I was hardly affected by the oral organic matter and that a mouth-washing or gargling solution containing PVP-I has a stronger bactericidal activity than BEC and CHG. Although mouth-washing and gargling samples were obtained from healthy individuals in this study, PVP-I may be used for protection against infections in patients with various diseases, if proper concentrations and usage are encouraged. PMID:16490985

  9. Short contact time direct coal liquefaction using a novel batch reactor. Quarterly technical progress report, September 15, 1995--January 15, 1996

    SciTech Connect

    Klein, M.T.; Calkins, W.H.; Huang, He

    1996-01-26

    The objective of this research is to optimize the design and operation of the bench scale batch reactor (SCTBR) f or coal liquefaction at short contact times (0.01 to 10 minutes or longer). Additional objectives are to study the kinetics of direct coal liquefaction particularly at short reaction times, and to investigate the role of the organic oxygen components of coal and their reaction pathways during liquefaction. Many of those objectives have already been achieved and others are still in progress. This quarterly report covers further progress toward those objectives.

  10. In vitro trans-scleral iontophoresis of methylprednisolone hemisuccinate with short application time and high drug concentration.

    PubMed

    Pescina, S; Martini, D; Santi, P; Padula, C; Murtomki, L; Nicoli, S

    2013-07-15

    Trans-scleral iontophoresis, i.e. the application of small electric current to enhance drug transport across sclera is an option for non-invasive delivery of corticosteroids to the posterior segment of the eye. In this paper, in vitro trans-scleral iontophoresis of methylprednisolone hemisuccinate was investigated using concentrated drug solutions and short application times to mimic the iontophoretic conditions of in vivo studies. The drug at the donor concentration of 45 mg/ml was delivered through isolated porcine sclera under passive and iontophoretic conditions (cathodal, 2.4 mA) for 2-15 min. In a second set of experiments, the drug was delivered for 5 min at current intensities of 0.9-7.2 mA. After donor removal, drug release was followed up to 24 h. The exposure of concentrated solutions to sclera for 2-15 min under passive conditions caused a notable accumulation of drug up to 0.8 mg/cm, the release of which was successively followed for 24 h. In cathodal iontophoresis, the amount of accumulated drug increased proportionally to the charge between 0.3 and 1.44 Coulomb. When the charge was increased to 2.16 Coulomb by increasing the application time or current intensity, no further enhancement was recorded. This behaviour can be ascribed to substantial drug adsorption on the scleral tissue, as demonstrated through streaming potential studies, with the consequent increase of the electroosmotic flow that opposes drug transport. The set up suggested here could help in defining the optimal conditions for in vivo studies with animal models and reducing the number of in vivo experiments. PMID:23628405

  11. The relationship between economic development and business ownership revisited

    Microsoft Academic Search

    Martin Carree; Andr Van Stel; Roy Thurik; Sander Wennekers

    2007-01-01

    This paper revisits the two-equation model of Carree, van Stel, Thurik and Wennekers (2002) where deviations from the equilibrium rate of business ownership play a central role in determining both the growth of business ownership and that of economic development. Two extensions of the original set-up are addressed: using longer time series of averaged data of 23 OECD countries (up

  12. The angular momentum of baryons and dark matter halos revisited

    Microsoft Academic Search

    Taysun Kimm; Julien Devriendt; Adrianne Slyz; Christophe Pichon; Susan A. Kassin; Yohan Dubois

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive mesh refinement, we find that at the time of accretion, gas and dark matter do carry a similar amount of specific

  13. Revisiting Size-Based Scheduling with Estimated Job Sizes

    E-print Network

    Carra, Damiano

    Revisiting Size-Based Scheduling with Estimated Job Sizes Matteo Dell'Amico EURECOM, France Damiano--We study size-based schedulers, and focus on the impact of inaccurate job size information on response time errors on job size estimates, thus limiting the applicability of size-based schedulers. We show

  14. The sun compass revisited.

    PubMed

    Guilford, Tim; Taylor, Graham K

    2014-11-01

    Many animals, and birds in particular, are thought to use directional information from the sun in the form of a time-compensated sun compass, with predictably deviated orientation under clock shift being regarded as the litmus test of this. We suggest that this paradigm obscures a number of other ways in which solar-derived information could be important in animal orientation. We distinguish between the known use of the sun's azimuth to provide absolute geographical direction (compass mechanism) and its possible use to detect changes in heading (heading indicator mechanism). Just as in an aircraft, these two kinds of information may be provided by separate mechanisms and used for different functions, for example for navigation versus steering. We also argue that although a solar compass must be time-referenced to account for the sun's apparent diurnal movement, this need not entail full time compensation. This is because animals might also use time-dependent solar information in an associatively acquired, and hence time-limited, way. Furthermore, we show that a solar heading indicator, when used on a sufficiently short timescale, need not require time compensation at all. Finally, we suggest that solar-derived cues, such as shadows, could also be involved in navigation in ways that depend explicitly upon position, and are therefore not strictly compass-related. This could include giving directionality to landmarks, or acting as time-dependent landmarks involved in place recognition. We conclude that clock shift experiments alone are neither necessary nor sufficient to identify the occurrence of all conceivable uses of solar information in animal orientation, so that a predictable response to clock shift should not be regarded as an acid test of the use of solar information in navigation. PMID:25389374

  15. The sun compass revisited

    PubMed Central

    Guilford, Tim; Taylor, Graham K.

    2014-01-01

    Many animals, and birds in particular, are thought to use directional information from the sun in the form of a time-compensated sun compass, with predictably deviated orientation under clock shift being regarded as the litmus test of this. We suggest that this paradigm obscures a number of other ways in which solar-derived information could be important in animal orientation. We distinguish between the known use of the sun's azimuth to provide absolute geographical direction (compass mechanism) and its possible use to detect changes in heading (heading indicator mechanism). Just as in an aircraft, these two kinds of information may be provided by separate mechanisms and used for different functions, for example for navigation versus steering. We also argue that although a solar compass must be time-referenced to account for the sun's apparent diurnal movement, this need not entail full time compensation. This is because animals might also use time-dependent solar information in an associatively acquired, and hence time-limited, way. Furthermore, we show that a solar heading indicator, when used on a sufficiently short timescale, need not require time compensation at all. Finally, we suggest that solar-derived cues, such as shadows, could also be involved in navigation in ways that depend explicitly upon position, and are therefore not strictly compass-related. This could include giving directionality to landmarks, or acting as time-dependent landmarks involved in place recognition. We conclude that clock shift experiments alone are neither necessary nor sufficient to identify the occurrence of all conceivable uses of solar information in animal orientation, so that a predictable response to clock shift should not be regarded as an acid test of the use of solar information in navigation. PMID:25389374

  16. Preparatory Body State before Reacting to an Opponent: Short-Term Joint Torque Fluctuation in Real-Time Competitive Sports

    PubMed Central

    Fujii, Keisuke; Yamashita, Daichi; Kimura, Tetsuya; Isaka, Tadao; Kouzaki, Motoki

    2015-01-01

    In a competitive sport, the outcome of a game is determined by an athletes relationship with an unpredictable and uncontrolled opponent. We have previously analyzed the preparatory state of ground reaction forces (GRFs) dividing non-weighted and weighted states (i.e., vertical GRFs below and above 120% of body weight, respectively) in a competitive ballgame task and demonstrated that the non-weighted state prevented delay of the defensive step and promoted successful guarding. However, the associated kinetics of lower extremity joints during a competitive sports task remains unknown. The present study aims to investigate the kinetic characteristics of a real-time competitive sport before movement initiation. As a first kinetic study on a competitive sport, we initially compared the successful defensive kinetics with a relatively stable preparatory state and the choice-reaction sidestep as a control movement. Then, we investigated the kinetic cause of the outcome in a 1-on-1 dribble in terms of the preparatory states according to our previous study. The results demonstrated that in successful defensive motions in the non-weighted state guarding trial, the times required for the generation of hip abduction and three extension torques for the hip, knee, and ankle joints were significantly shortened compared with the choice-reaction sidestep, and hip abduction and hip extension torques were produced almost simultaneously. The sport-specific movement kinetics emerges only in a more-realistic interactive experimental setting. A comparison of the outcomes in the 1-on-1 dribble and preparatory GRF states showed that, in the non-weighted state, the defenders guarded successfully in 68.0% of the trials, and the defenders initiation time was earlier than that in the weighted state (39.1%). In terms of kinetics, the root mean squares of the derivative of hip abduction and three extension torques in the non-weighted state were smaller than those in the weighted state, irrespective of the outcome. These results indicate that the preparatory body state as explained by short-term joint torque fluctuations before the defensive step would help explain the performance in competitive sports, and will give insights into understanding human adaptive behavior in unpredicted and uncontrolled environments. PMID:26024485

  17. Short-time windowed covariance: A metric for identifying non-stationary, event-related covariant cortical sites

    PubMed Central

    Blakely, Timothy; Ojemann, Jeffrey G.; Rao, Rajesh P.N.

    2014-01-01

    Background Electrocorticography (ECoG) signals can provide high spatio-temporal resolution and high signal to noise ratio recordings of local neural activity from the surface of the brain. Previous studies have shown that broad-band, spatially focal, high-frequency increases in ECoG signals are highly correlated with movement and other cognitive tasks and can be volitionally modulated. However, significant additional information may be present in inter-electrode interactions, but adding additional higher order inter-electrode interactions can be impractical from a computational aspect, if not impossible. New method In this paper we present a new method of calculating high frequency interactions between electrodes called Short-Time Windowed Covariance (STWC) that builds on mathematical techniques currently used in neural signal analysis, along with an implementation that accelerates the algorithm by orders of magnitude by leveraging commodity, off-the-shelf graphics processing unit (GPU) hardware. Results Using the hardware-accelerated implementation of STWC, we identify many types of event-related inter-electrode interactions from human ECoG recordings on global and local scales that have not been identified by previous methods. Unique temporal patterns are observed for digit flexion in both low- (10 mm spacing) and high-resolution (3 mm spacing) electrode arrays. Comparison with existing methods Covariance is a commonly used metric for identifying correlated signals, but the standard covariance calculations do not allow for temporally varying covariance. In contrast STWC allows and identifies event-driven changes in covariance without identifying spurious noise correlations. Conclusions: STWC can be used to identify event-related neural interactions whose high computational load is well suited to GPU capabilities. PMID:24211499

  18. Using the Advanced Progressive Matrices (Set I) to Assess Fluid Ability in a Short Time Frame: An Item Response Theory-Based Analysis

    ERIC Educational Resources Information Center

    Chiesi, Francesca; Ciancaleoni, Matteo; Galli, Silvia; Primi, Caterina

    2012-01-01

    This article is aimed at evaluating the possibility that Set I of the Advanced Progressive Matrices (APM-Set I) can be employed to assess fluid ability in a short time frame. The APM-Set I was administered to a sample of 1,389 primary and secondary school students. Confirmatory factor analysis attested to the unidimensionality of the scale. Item

  19. Electroencephalographic recordings in dogs suffering from idiopathic and symptomatic epilepsy: Diagnostic value of interictal short time EEG protocols supplemented by two activation techniques

    Microsoft Academic Search

    Christina Brauer; Sabine B. R. Kstner; Karl Rohn; Henning C. Schenk; Julia Tnsmeyer; Andrea Tipold

    The diagnostic value of interictal short time electroencephalographic (EEG) recordings in epileptic dogs under general anaesthesia with propofol and the muscle relaxant rocuronium bromide was investigated. Two activation techniques, namely photic stimulation and hyperventilation, were evaluated for their potential to enhance the diagnostic validity of these recordings. Sixty-one dogs suffering from idiopathic epilepsy and 28 dogs suffering from symptomatic epilepsy

  20. Measurement of Mechanical Properties of Solid Fuels and Advanced Composite Materials Related to Short-Time High Acceleration Generated by Lorentz Rail Accelerators

    Microsoft Academic Search

    Daniel Lancelle; Ognjan Bozic; Jan Martinez Schramm; Stefan Linke

    2011-01-01

    The technology of electromagnetic driven Lorentz rail accelerators (LRAs) has been significantly improved in the last years. Due to the extreme acceleration in LRA systems, there are high demands regarding the mechanical stresses. It is assumed that materials can withstand stresses exceeding the nominal limits related to static conditions if they are applied for a short time. To assess the

  1. DEWEK Wind Energy Conference 2012 Category: 4. Simulation models BACKWARD EXTRAPOLATION OF SHORT-TIME MEASUREMENT DATA FOR A REMAINING SERVICE LIFE ESTIMATION OF WIND

    E-print Network

    Berlin,Technische Universitt

    DEWEK Wind Energy Conference 2012 Category: 4. Simulation models 1 BACKWARD EXTRAPOLATION OF SHORT-TIME MEASUREMENT DATA FOR A REMAINING SERVICE LIFE ESTIMATION OF WIND TURBINES Dipl.-Ing. Ren Kamieth, Prof. Dr, Germany, Tel.: +49-(0)30-314-23603, Fax: +49-(0)30-314-26131 Summary Wind turbines built in the last

  2. Thermal scene analysis via finite element model and finite difference time domain numerical solution of the electromagnetic wave propagation in the short wave and long wave infrared bandarch

    Microsoft Academic Search

    Alessandro Albertoni

    2009-01-01

    We utilize the Finite Element Model (FEM) and Finite Difference Time Domain (FDTD) numerical solution of the Electromagnetic wave propagation in the Short Wave Infrared (SWIR) and Long Wave Infrared (LWIR) bands in order to calculate the target radiance propagation and environment attenuation due to transmission, absorption and reflections in atmosphere and obstacles. We leave to traditional minimum resolvable temperature

  3. Investigating routes to chaos in the guinea-pig cochlea using the continuous wavelet transform and the short-time Fourier transform

    Microsoft Academic Search

    M. C. Teich; C. Heneghan; S. M. Khanna; . Flock; M. Ulfendahl; L. Brundin

    1995-01-01

    The continuous wavelet transform (CWT) and the short-time Fourier transform (STFT) were used to analyze the time course of\\u000a cellular motion in the guinea pig inner ear. The velocity responses of individual outer hair cells and Hensen's cells to amplitude\\u000a modulated (AM) acoustical signals applied to the ear canal displayed characteristics typical of nonlinear systems, such as\\u000a the generation of

  4. Keep it simple: on specific-to-general predictor selection for time series forecasting in the short, medium and long run

    Microsoft Academic Search

    Helmut Herwartz

    2011-01-01

    This paper describes the forecasting performance of general-to-specific and specific-to-general predictor selection within specifications fitting into the class of (approximate) linear autoregressions. Short, medium and long horizon forecasting exercises are distinguished. Regarding the latter, iterative prediction is compared with direct conditioning on available time series information. Ex ante forecasting results are provided for 495 real macro-economic and financial time series

  5. Means and method for characterizing high power, ultra short laser pulses in a real time, on line manner

    DOEpatents

    Veligdan, James T. (Manorville, NY)

    1994-01-01

    An ultra short (<10 ps), high power laser pulse is temporally characterized by a system that uses a physical measurement of a wavefront that has been altered in a known manner. The system includes a first reflection switch to remove a portion of a pulse from a beam of pulses, then includes a second reflection switch, operating in a mode that is opposite to the first reflection switch, to slice off a portion of that removed portion. The sliced portion is then directed to a measuring device for physical measurement. The two reflection switches are arranged with respect to each other and with respect to the beam of ultra short pulses such that physical measurement of the sliced portion is related to the temporal measurement of the ultra short pulse by a geometric or trigonometric relationship. The reflection switches are operated by a control pulse that is directed to impinge on each of the reflection switches at a 90.degree. angle of incidence.

  6. Pharmacy School Survey Standards Revisited

    PubMed Central

    Barnett, Mitchell J.; Lenth, Russell V.; Knapp, Katherine K.

    2013-01-01

    In a series of 3 papers on survey practices published from 2008 to 2009, the editors of the American Journal of Pharmaceutical Education presented guidelines for reporting survey research, and these criteria are reflected in the Author Instructions provided on the Journals Web site. This paper discusses the relevance of these criteria for publication of survey research regarding pharmacy colleges and schools. In addition, observations are offered about surveying of small "universes" like that comprised of US colleges and schools of pharmacy. The reason for revisiting this issue is the authors concern that, despite the best of intentions, overly constraining publication standards might discourage research on US colleges and schools of pharmacy at a time when the interest in the growth of colleges and schools, curricular content, clinical education, competence at graduation, and other areas is historically high. In the best traditions of academia, the authors share these observations with the community of pharmacy educators in the hope that the publication standards for survey research about US pharmacy schools will encourage investigators to collect and disseminate valuable information. PMID:23459404

  7. Short-time Flexure of The East Greenland Rifted Margin From Direct 40 Ar/39ar Datings of Basaltic Dykes

    NASA Astrophysics Data System (ADS)

    Lenoir, X.; Fraud, G.; Geoffroy, L.

    The SE Greenland volcanic margin is characterized by a intense coastal flexure during the continental breakup in the N Atlantic. This flexure is attested by field and geo- physical observations as dipping of coast-parallel dyke swarm and mafic intrusions, and seaward dipping reflectors sequences. These magmatic structures are contempo- raneous with flexuring. By dating dykes of different dippings, we may estimate the rate of crustal deformation along and across the margin. This study is part of a mul- tidisciplinary program (GDR-Marges) concerning the definition of a volcanic marge model. We present preliminary age data on pairs of dykes from the same locations, the first tilted crossed by the second vertical. We sampled twelve pairs of basaltic dykes in two sites on the E Greenland margin: at Cap Wandel (6620'N) and Cap Gustav Holm (6640'N). Angular difference between tilted- and vertical dykes range from 25 to 40 degree. On both localities, dykes are tholeiites with doleritic or mi- crolitic porphyric textures with plagioclase , calcic augite, Fe-Ti oxides, scarce olivine and variable amount of amphibole or biotite. On the basis of alteration criteria, we se- lected six fresh dyke pairs for datings. The main problem of direct dating of dykes in E Greenland margin, is the existence of variable amounts of excess argon, and all whole rock, plagioclase and amphibole show saddle shaped age spectra. Nevertheless, very detailed age spectra on unaltered minerals allow to estimate maximum ge differences (and therefore minimum flexuring rates). In Cap Wandel, two plagioclases from tilted and vertical dykes show saddle shaped age spectra, but similar ages of 49.9 +/- 0.9 Ma and 50.8 +/- 0.6 Ma, on mini plateau age, and minimum apparent age , respectively. In Cap Gustave, amphibole for the tilted dyke gives a maximum age (minimum on saddle shape) of 54.2 +/- 0.3 Ma, and biotite from the vertical dyke displays a plateau age of 51.0 +/- 0.15 Ma. These two ages represent a maximum age difference (of about 3.2 Ma) between tilted and vertical dykes. If all dykes were emplaced vertically, estima- tions of the flexure rate are in the range 12.5-30 /Ma, that imply a short-time flexure of E Greenland margin. As rocks have been sampled in the strong deformation zones (magmatic dilatation and flexure) with deformation velocity of about 10-14 s-1, we propose that volcanic margins distinguish from non-volcanic passive margins or rifts by a distinct crustal rheology with higher deformation velocity.

  8. Seasonal and short time gravity changes due to monsoonal rainfall in West Africa using a superconducting gravimeter

    NASA Astrophysics Data System (ADS)

    Hector, Basile; Hinderer, Jacques; Sguis, Luc; Boy, Jean-Paul; Calvo, Marta; Descloitres, Marc; Rosat, Sverine; Riccardi, Umberto

    2013-04-01

    A superconducting gravimeter (SG) has been installed since 2010 in Djougou, northern Benin, within the framework of the GHYRAF (Gravity and Hydrology in Africa) project. This site was first measured with a FG5 absolute gravimeter four times a year from 2008 to 2011. It was then decided to install a superconducting gravimeter in order to monitor in a continuous way the strong annual monsoon signal with both local and non-local hydrological contributions within the humid sudanian zone of West-Africa. The area is also part of the long-term observing system AMMA-Catch, and thus under intense hydro-meteorological monitoring (rain, soil moisture, water table level, evapotranspiration, etc). We present here the results of the first two years relative gravity monitoring with SG-060 from GWR Instruments. FG5 absolute gravity data are used for calibration and drift estimate of the SG. As everywhere on the GGP (Global Geodynamics project) stations, the signal includes solid earth tides, ocean loading, polar motion, atmospheric pressure effects, drift and water storage changes (WSC). The barometric corrections are more complicated than for mid-latitude stations; indeed pressure effects are of major concern in the equatorial band, because they are governed by S1 and S2 thermal pressure waves. These waves dominate both the local Newtonian effect (an increase in local pressure decreases the gravity) and the smaller non-local loading effect (an increase in regional pressure decreases the gravity mostly by a subsidence effect of the elastic earth) because of their coherency at the regional scale. We focus here on two predominant frequencies: first the seasonal cycle where we compare the seasonal gravity signal left in the residuals after correction for solid Earth and ocean tides, atmosphere, polar motion and long term drift to Water Storage Changes (WSC) computed from observations in soil moisture (using neutronic measurements) and water table variations. Second we investigate the gravity signature of short term rainfall events. This includes both the rapid increase in gravity following a precipitation, and the slower decrease afterwards, related to evapotranspiration rates and underground water redistribution. In particular we will show the so-called 'shelter effect' which reduces the apparent rain-gravity admittance (in terms of Gal per mm of rain). We will try to derive a general model for our site from the analysis of numerous rain events during the summer monsoon.

  9. Revisiting the schism.

    PubMed

    Litsios, Socrates

    2014-01-01

    The schism between medicine and public health has deep historical roots. The Rockefeller Foundation's Clinical Epidemiology program, initiated in the late 1970s, was seen by Kerr White, its director, as the means to heal the schism. This article revisits the role that the Foundation played in creating that schism before reviewing post-World War II efforts on the part of both the Foundation and the World Health Organization to incorporate the teaching of preventive medicine in medical education curricula. White labeled these efforts as failures, but a closer look at the history raises questions concerning what evidence he used to make this judgment and whether clinical epidemiology has not instead widened the gap between cure and prevention. PMID:25626230

  10. Automatized near-real-time short-term Probabilistic Volcanic Hazard Assessment of tephra dispersion before eruptions: BET_VHst for Vesuvius and Campi Flegrei during recent exercises

    NASA Astrophysics Data System (ADS)

    Selva, Jacopo; Costa, Antonio; Sandri, Laura; Rouwet, Dmtri; Tonini, Roberto; Macedonio, Giovanni; Marzocchi, Warner

    2015-04-01

    Probabilistic Volcanic Hazard Assessment (PVHA) represents the most complete scientific contribution for planning rational strategies aimed at mitigating the risk posed by volcanic activity at different time scales. The definition of the space-time window for PVHA is related to the kind of risk mitigation actions that are under consideration. Short temporal intervals (days to weeks) are important for short-term risk mitigation actions like the evacuation of a volcanic area. During volcanic unrest episodes or eruptions, it is of primary importance to produce short-term tephra fallout forecast, and frequently update it to account for the rapidly evolving situation. This information is obviously crucial for crisis management, since tephra may heavily affect building stability, public health, transportations and evacuation routes (airports, trains, road traffic) and lifelines (electric power supply). In this study, we propose a methodology named BET_VHst (Selva et al. 2014) for short-term PVHA of volcanic tephra dispersal based on automatic interpretation of measures from the monitoring system and physical models of tephra dispersal from all possible vent positions and eruptive sizes based on frequently updated meteorological forecasts. The large uncertainty at all the steps required for the analysis, both aleatory and epistemic, is treated by means of Bayesian inference and statistical mixing of long- and short-term analyses. The BET_VHst model is here presented through its implementation during two exercises organized for volcanoes in the Neapolitan area: MESIMEX for Mt. Vesuvius, and VUELCO for Campi Flegrei. References Selva J., Costa A., Sandri L., Macedonio G., Marzocchi W. (2014) Probabilistic short-term volcanic hazard in phases of unrest: a case study for tephra fallout, J. Geophys. Res., 119, doi: 10.1002/2014JB011252

  11. Short-Term and Long-Term Consequences of Achievement Goals: Predicting Interest and Performance Over Time

    Microsoft Academic Search

    Judith M. Harackiewicz; Kenneth E. Barron; John M. Tauer; Suzanne M. Carter; Andrew J. Elliot

    2000-01-01

    Why do some students excel in their college classes and develop interest in an academic discipline? The authors examined both the short-term and long-term consequences of students' achievement goals in an introductory psychology course. Mastery goals positively predicted subsequent interest in the course, but not course grades. Performance goals positively predicted grades, but not interest. Three semesters later, the authors

  12. Balancing the Need for Reliability and Time Efficiency: Short Forms of the Wechsler Adult Intelligence Scale-III

    ERIC Educational Resources Information Center

    Jeyakumar, Sharon L. E.; Warriner, Erin M.; Raval, Vaishali V.; Ahmad, Saadia A.

    2004-01-01

    Tables permitting the conversion of short-form composite scores to full-scale IQ estimates have been published for previous editions of the Wechsler Adult Intelligence Scale (WAIS). Equivalent tables are now needed for selected subtests of the WAIS-III. This article used Tellegen and Briggs's formulae to convert the sum of scaled scores for four

  13. 26 CFR 1.6074-2 - Time for filing declarations by corporations in case of a short taxable year.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Time for filing declarations by corporations...CONTINUED) INCOME TAXES (CONTINUED) Time for Filing Returns and Other Documents 1.6074-2 Time for filing declarations by...

  14. 26 CFR 1.6074-2 - Time for filing declarations by corporations in case of a short taxable year.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Time for filing declarations by corporations...CONTINUED) INCOME TAXES (CONTINUED) Time for Filing Returns and Other Documents 1.6074-2 Time for filing declarations by...

  15. 26 CFR 1.6074-2 - Time for filing declarations by corporations in case of a short taxable year.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Time for filing declarations by corporations...CONTINUED) INCOME TAXES (CONTINUED) Time for Filing Returns and Other Documents 1.6074-2 Time for filing declarations by...

  16. 26 CFR 1.6074-2 - Time for filing declarations by corporations in case of a short taxable year.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Time for filing declarations by corporations...CONTINUED) INCOME TAXES (CONTINUED) Time for Filing Returns and Other Documents 1.6074-2 Time for filing declarations by...

  17. 26 CFR 1.6074-2 - Time for filing declarations by corporations in case of a short taxable year.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Time for filing declarations by corporations...INCOME TAX (CONTINUED) INCOME TAXES Time for Filing Returns and Other Documents 1.6074-2 Time for filing declarations by...

  18. Reply to comment on "A simple model for the short-time evolution of near-surface current and temperature profiles"

    E-print Network

    Jenkins, A D; Jenkins, Alastair D.; Ward, Brian

    2005-01-01

    This is our response to a comment by Walter Eifler on our paper `A simple model for the short-time evolution of near-surface current and temperature profiles' (arXiv:physics/0503186, accepted for publication in Deep-Sea Research II). Although Eifler raises genuine issues regarding our model's validity and applicability, we are nevertheless of the opinion that it is of value for the short-term evolution of the upper-ocean profiles of current and temperature. The fact that the effective eddy viscosity tends to infinity for infinite time under a steady wind stress may not be surprising. It can be interpreted as a vertical shift of the eddy viscosity profile and an increase in the size of the dominant turbulent eddies under the assumed conditions of small stratification and infinite water depth.

  19. The bacterial nucleoid revisited.

    PubMed Central

    Robinow, C; Kellenberger, E

    1994-01-01

    This review compares the results of different methods of investigating the morphology of nucleoids of bacteria grown under conditions favoring short generation times. We consider the evidence from fixed and stained specimens, from phase-contrast and fluorescence microscopy of growing bacteria, and from electron microscopy of whole as well as thinly sectioned ones. It is concluded that the nucleoid of growing cells is in a dynamic state: part of the chromatin is "pulled out" of the bulk of the nucleoid in order to be transcribed. This activity is performed by excrescences which extend far into the cytoplasm so as to reach the maximum of available ribosomes. Different means of fixation provide markedly different views of the texture of the DNA-containing plasm of the bulk of the nucleoid. Conventional chemical fixatives stabilize the cytoplasm of bacteria but not their protein-low chromatin. Uranyl acetate does cross-link the latter well but only if the cytoplasm has first been fixed conventionally. In the interval between the two fixations, the DNA arranges itself in liquid-crystalline form, supposedly because of loss of supercoiling. In stark contrast, cryofixation preserves bacterial chromatin in a finely granular form, believed to reflect its native strongly negatively supercoiled state. In dinoflagellates the DNA of their permanently visible chromosomes (also low in histone-like protein) is natively present as a liquid crystal. The arrangement of chromatin in Epulocystis fishelsoni, one of the largest known prokaryotes, is briefly described. Images PMID:7521510

  20. Detection of short pure-tone stimuli in the noctuid ear: what are temporal integration and integration time all about?

    Microsoft Academic Search

    J. Tougaard

    1998-01-01

    Temporal integration in the A1 acoustic receptor cell of noctuid moths (Lepidoptera: Noctuidae) was studied. This was done\\u000a by recording from the auditory nerve of Spodoptera littoralis and Noctua pronuba while stimulating with short-duration tone pulses. Consistent with previous experiments of the same kind, a decrease in threshold\\u000a was observed with increasing stimulus duration. These threshold improvements, however, were larger

  1. EPISTATIC INTERACTIONS OF THREE LOCI REGULATE FLOWERING TIME UNDER SHORT AND LONG DAYLENGTHS IN A BACKCROSS POPULATION OF RICE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The short-day plant rice varies greatly in photoperiod sensitivity (PS) for flowering. The hybrid F1 from a cross between the day-neutral pure line EM93-1 and the weedy rice accession SS18-2 had stronger PS than SS18-2. Some BC1 (EM93-1/ F1) segregates were even more sensitive to photoperiod than th...

  2. Cretaceous eustasy revisited

    NASA Astrophysics Data System (ADS)

    Haq, Bilal U.

    2014-02-01

    Eustatic sea-level changes of the Cretaceous are reevaluated based on a synthesis of global stratigraphic data. A new terminology for local/regional or relative sea-level changes (eurybatic shifts) is proposed to distinguish them from global (eustatic) sea-level changes, with the observation that all measures of sea-level change in any given location are eurybatic, even when they include a strong global signal. Solid-earth factors that influence inherited regional topography and thus modify physical measures of amplitude of the sea-level rises and falls locally are reviewed. One of these factors, dynamic topography (surface expression of mass flow in the upper mantle on land- and seascapes), is considered most pertinent in altering local measures of amplitude of sea-level events on third-order time scales (0.5-3.0 Myr). Insights gained from these models have led to the reconciliation of variance between amplitude estimates of eurybatic shifts in any given region and global measures of eustatic changes. Global estimates of third-order events can only be guesstimated at best by averaging the eurybatic data from widely distributed time-synchronous events. Revised curves for both long-term and short-term sea-level variations are presented for the Cretaceous Period. The curve representing the long-term envelope shows that average sea levels throughout the Cretaceous remained higher than the present day mean sea level (75-250 m above PDMSL). Sea level reached a trough in mid Valanginian (~ 75 m above PDMSL), followed by two high points, the first in early Barremian (~ 160-170 m above PDMSL) and the second, the highest peak of the Cretaceous, in earliest Turonian (~ 240-250 m above PDMSL). The curve also displays two ~ 20 Myr-long periods of relatively high and stable sea levels (Aptian through early Albian and Coniacian through Campanian). The short-term curve identifies 58 third-order eustatic events in the Cretaceous, most have been documented in several basins, while a smaller number are included provisionally as eustatic, awaiting confirmation. The amplitude of sea-level falls varies from a minimum of ~ 20 m to a maximum of just over 100 m and the duration varies between 0.5 and 3 Myr. The causes for these relatively rapid, and at times large amplitude, sea-level falls in the Cretaceous remain unresolved, although based mainly on oxygen-isotopic data, the presence of transient ice cover on Antarctica as the driver remains in vogue as an explanation. This idea has, however, suffered a recent setback following the discovery of pristine foraminiferal tests in the Turonian of Tanzania whose oxygen-isotopic values show little variation, implying absence of glacioeustasy at least in the Turonian. The prevalence of 4th-order (~ 400 Kyr) cyclicity through most of the Cretaceous (and elsewhere in the Paleozoic, Jurassic and Cenozoic) implies that the periodicity on this time scale, presumably driven by long-term orbital eccentricity, may be a fundamental feature of depositional sequences throughout the Phanerozoic.

  3. Short term effects of temperature on risk of myocardial infarction in England and Wales: time series regression analysis of the Myocardial Ischaemia National Audit Project (MINAP) registry

    Microsoft Academic Search

    Krishnan Bhaskaran; Shakoor Hajat; Andy Haines; Emily Herrett; Paul Wilkinson; Liam Smeeth

    2010-01-01

    Objective To examine the short term relation between ambient temperature and risk of myocardial infarction.Design Daily time series regression analysis.Setting 15 conurbations in England and Wales.Participants 84 010 hospital admissions for myocardial infarction recorded in the Myocardial Ischaemia National Audit Project during 2003-6 (median 57 events a day).Main outcome measures Change in risk of myocardial infarction associated with a 1C

  4. EFFECTS OF THERMAL-MECHANICAL PROCESSING VARIABLES ON SHORT-TIME 3000 F TENSILE PROPERTIES OF TUNGSTEN + 0.6 PERCENT COLUMBIUM ALLOY

    Microsoft Academic Search

    V. DePierre; G. Saul

    1963-01-01

    The effects of thermal-mechanical processing variables on short-time ; 3000 deg F tensile properties of tungsten + 0.6 percent niobium alloy were ; determined by correlating both tensile properties and thermal-mechanical ; variables with microstructure and cold work condition of this alloy. From these ; correlations the spread in 3000 deg F tensile and yield strength values (22,000to ; 63,310

  5. Two short questionnaires on leisure-time physical activity compared with serum lipids, anthropometric measurements and aerobic power in a suburban population from Oslo, Norway

    Microsoft Academic Search

    Sidsel Graff-Iversen; Sigmund Alfred Anderssen; Ingar Morten Holme; Anne Karen Jenum; Truls Raastad

    2008-01-01

    The aim was to indirectly validate two short postal questionnaires measuring leisure-time physical activity (LPA) by comparing\\u000a the answers with serum lipids and anthropometric measurements. Methods All inhabitants aged 3167years in two suburban, multicultural areas of Oslo, Norway were invited to Romss in Motion,\\u000a a community intervention survey, in 2000. Of those, 2950 participants (48%) met and were re-invited in

  6. Means and method for characterizing high power, ultra short laser pulses in a real time, on line manner

    DOEpatents

    Veligdan, J.T.

    1994-03-08

    An ultra short (<10 ps), high power laser pulse is temporally characterized by a system that uses a physical measurement of a wavefront that has been altered in a known manner. The system includes a first reflection switch to remove a portion of a pulse from a beam of pulses, then includes a second reflection switch, operating in a mode that is opposite to the first reflection switch, to slice off a portion of that removed portion. The sliced portion is then directed to a measuring device for physical measurement. The two reflection switches are arranged with respect to each other and with respect to the beam of ultra short pulses such that physical measurement of the sliced portion is related to the temporal measurement of the ultra short pulse by a geometric or trigonometric relationship. The reflection switches are operated by a control pulse that is directed to impinge on each of the reflection switches at a 90[degree] angle of incidence. 8 figures.

  7. 42 CFR 488.30 - Revisit user fee for revisit surveys.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...billing for a fee already paid, or assessment of a fee...toward any future revisit surveys conducted, if the provider...revisit user fee amount paid to the provider or supplier...request reconsideration of the survey findings or...

  8. 42 CFR 488.30 - Revisit user fee for revisit surveys.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...billing for a fee already paid, or assessment of a fee...toward any future revisit surveys conducted, if the provider...revisit user fee amount paid to the provider or supplier...request reconsideration of the survey findings or...

  9. Re-visiting the nature and relationships between neurological signs and neurocognitive functions in first-episode schizophrenia: An invariance model across time.

    PubMed

    Chan, Raymond C K; Dai, Shan; Lui, Simon S Y; Ho, Karen K Y; Hung, Karen S Y; Wang, Ya; Geng, Fu-Lei; Li, Zhi; Cheung, Eric F C

    2015-01-01

    The present study examined different types of neurological signs in patients with first-episode schizophrenia and their relationships with neurocognitive functions. Both cross-sectional and longitudinal designs were adopted with the use of the abridged Cambridge Neurological Inventory which comprises items capturing motor coordination, sensory integration and disinhibition. A total of 157 patients with first-episode schizophrenia were assessed at baseline and 101 of them were re-assessed at six-month interval. A structural equation model (SEM) with invariance model across time was used for data analysis. The model fitted well with the data at baseline assessment, X^2(21)?=?21.78, p?=?0.413, NFI?=?0.95, NNFI?=?1.00, CFI?=?1.00, IFI?=?1.00, RMSEA?=?0.015. Subsequent SEM analysis with invariance model at six-month interval also demonstrated the same stable pattern across time and showed strong measurement invariance and structure invariance across time. Our findings suggest that neurological signs capture more or less the same construct captured by conventional neurocognitive tests in patients with schizophrenia. The measurement and structure of these relationships appear to be stable over time. PMID:26136150

  10. Automatized near-real-time short-term Probabilistic Volcanic Hazard Assessment of tephra dispersion before and during eruptions: BET_VHst for Mt. Etna

    NASA Astrophysics Data System (ADS)

    Selva, Jacopo; Scollo, Simona; Costa, Antonio; Brancato, Alfonso; Prestifilippo, Michele

    2015-04-01

    Tephra dispersal, even in small amounts, may heavily affect public health and critical infrastructures, such as airports, train and road networks, and electric power supply systems. Probabilistic Volcanic Hazard Assessment (PVHA) represents the most complete scientific contribution for planning rational strategies aimed at managing and mitigating the risk posed by activity during volcanic crises and during eruptions. Short-term PVHA (over time intervals in the order of hours to few days) must account for rapidly changing information coming from the monitoring system, as well as, updated wind forecast, and they must be accomplished in near-real-time. In addition, while during unrest the primary goal is to forecast potential eruptions, during eruptions it is also fundamental to correctly account for the real-time status of the eruption and of tephra dispersal, as well as its potential evolution in the short-term. Here, we present a preliminary application of BET_VHst model (Selva et al. 2014) for Mt. Etna. The model has its roots into present state deterministic procedure, and it deals with the large uncertainty that such procedures typically ignore, like uncertainty on the potential position of the vent and eruptive size, on the possible evolution of volcanological input during ongoing eruptions, as well as, on wind field. Uncertainty is treated by making use of Bayesian inference, alternative modeling procedures for tephra dispersal, and statistical mixing of long- and short-term analyses. References Selva J., Costa A., Sandri L., Macedonio G., Marzocchi W. (2014) Probabilistic short-term volcanic hazard in phases of unrest: a case study for tephra fallout, J. Geophys. Res., 119, doi: 10.1002/2014JB011252

  11. Searle's"Dualism Revisited"

    SciTech Connect

    P., Henry

    2008-11-20

    A recent article in which John Searle claims to refute dualism is examined from a scientific perspective. John Searle begins his recent article 'Dualism Revisited' by stating his belief that the philosophical problem of consciousness has a scientific solution. He then claims to refute dualism. It is therefore appropriate to examine his arguments against dualism from a scientific perspective. Scientific physical theories contain two kinds of descriptions: (1) Descriptions of our empirical findings, expressed in an every-day language that allows us communicate to each other our sensory experiences pertaining to what we have done and what we have learned; and (2) Descriptions of a theoretical model, expressed in a mathematical language that allows us to communicate to each other certain ideas that exist in our mathematical imaginations, and that are believed to represent, within our streams of consciousness, certain aspects of reality that we deem to exist independently of their being perceived by any human observer. These two parts of our scientific description correspond to the two aspects of our general contemporary dualistic understanding of the total reality in which we are imbedded, namely the empirical-mental aspect and the theoretical-physical aspect. The duality question is whether this general dualistic understanding of ourselves should be regarded as false in some important philosophical or scientific sense.

  12. THE WATER CYCLE REVISITED:THE WATER CYCLE REVISITED: LINKAGES WITH ELEMENTLINKAGES WITH ELEMENT

    E-print Network

    Slatton, Clint

    THE WATER CYCLE REVISITED:THE WATER CYCLE REVISITED: LINKAGES WITH ELEMENTLINKAGES WITH ELEMENT?s to revisit? #12;USGCRP Water Cycle Science Plan Hornberger et al. 2001 (3rd Science Question) How will variability and changes in the cycling of water though terrestrial and freshwater ecosystems be linked

  13. Preparing for STEREO - Revisit Helios!

    NASA Astrophysics Data System (ADS)

    Schwenn, R.

    2004-12-01

    Exactly 30 years ago, the first Helios solar probe was launched into an elliptical heliocentric orbit, with a perihelion of 0.3 AU. It had a set of then modern particle and field instruments on board, but no imagers. One year later, an almost identical probe was put into a very similar orbit, approaching the Sun even a bit closer. For most of their common lifetime of 4 years, the two probes were separated in longitude by no more than about 30 degrees. Further, due to their special orbits, they spent many months above the Sun's limb (as seen from Earth). In conjunction with the Earth-orbiting IMP 7&8 satellites and the Voyager 1&2, and the Pioneer 10&11 space probes, real multipoint studies covering large parts of the heliosphere could be performed successfully for the first time. The Helios mission resembled the upcoming STEREO mission in several respects and was indeed of good use for defining the STEREO science goals. For example, Helios could reveal details about the longitudinal and latitudinal solar wind stream structure, it allowed unique associations between limb CMEs and their radial propagation towards an in-situ observer, and the propagation of solar energetic particles could be studied. However, since then our understanding of the heliosphere has improved considerably, thanks to recent space missions (Ulysses, Yohkoh, SOHO, Wind, ACE) and to more and more refined theoretical models. In view of these new results, it appears worthwhile to revisit the huge Helios data sets since they certainly keep hiding some answers that future observations from STEREO might benefit from.

  14. Internet Governance revisited: Think decentralization!

    E-print Network

    Schweik, Charles M.

    Internet Governance revisited: Think decentralization! Brown-bag presentation given at the National Administration of the core technical resources of the Internet: ICANN: The mission... ,,preserving the public of the Internet" #12;unique identifiers basis for accurate routing of information (TCP/IP) IP-blocks managed

  15. Axion Quintessence Revisited Carl Gardner

    E-print Network

    Gardner, Carl

    Axion Quintessence Revisited Carl Gardner School of Mathematical & Statistical Sciences Arizona;Axion Quintessence Define /MP Focus on stable & unstable axion quintessence with DE,0 = 0.72 & -1 axion quintessence V() = A cos(), 0 i/ 0.23 produces a universe like

  16. Message Authentication, Revisited Yevgeniy Dodis

    E-print Network

    Message Authentication, Revisited Yevgeniy Dodis Eike Kiltz Krzysztof Pietrzak Daniel Wichs October 28, 2012 Abstract Traditionally, symmetric-key message authentication codes (MACs) are easily a state-of-the-art PRF instantiation under the corresponding assumption. For example, we obtain elegant

  17. Revisiting Money - Interest Rate Relationship

    Microsoft Academic Search

    Srivyal Vuyyuri; Ganesh S Mani; Chakrapani V Chaturvedula

    2003-01-01

    This paper tries to revisit the relationship between money supply and interest rates. Data for countries from 1981 to 1998 seem to support the positive relationship between the two variables as described by the Fisher equation. The empirical findings have been substantiated by a simple mathematical model. It incorporates the Fisher equation view as well as the liquidity effect and

  18. Revisiting constraint-directed search

    Microsoft Academic Search

    Magnus gren; Pierre Flener; Justin Pearson

    2009-01-01

    We revisit the exploration of constraint-directed neighbour- hoods, where a (small) set of constraints is picked before considering the neighbouring configurations where those constraints have a decreased (or preserved, or increased) penalty. Given the semantics of a constraint, such neighbourhoods can be represented via new attributes or primi- tives for the corresponding constraint object. We show how to define these

  19. Blockcipher-Based Hashing Revisited

    Microsoft Academic Search

    Martijn Stam

    2009-01-01

    We revisit the rate-1 blockcipher based hash functions as first studied by Preneel, Govaerts and Vandewalle (Crypto'93) and later extensively analysed by Black, Rogaway and Shrimpton (Crypto'02). We analyse a further generalization where any pre- and postprocessing is considered. This leads to a clearer under- standing of the current classification of rate-1 blockcipher based schemes as introduced by Preneel et

  20. On the relationship between time-series studies, dynamic population studies, and estimating loss of life due to short-term exposure to environmental risks.

    PubMed Central

    Burnett, Richard T; Dewanji, Anup; Dominici, Francesca; Goldberg, Mark S; Cohen, Aaron; Krewski, Daniel

    2003-01-01

    There is a growing concern that short-term exposure to combustion-related air pollution is associated with increased risk of death. This finding is based largely on time-series studies that estimate associations between daily variations in ambient air pollution concentrations and in the number of nonaccidental deaths within a community. Because these results are not based on cohort or dynamic population designs, where individuals are followed in time, it has been suggested that estimates of effect from these time-series studies cannot be used to determine the amount of life lost because of short-term exposures. We show that results from time-series studies are equivalent to estimates obtained from a dynamic population when each individual's survival experience can be summarized as the daily number of deaths. This occurs when the following conditions are satisfied: a) the environmental covariates vary in time and not between individuals; b) on any given day, the probability of death is small; c) on any given day and after adjusting for known risk factors for mortality such age, sex, smoking habits, and environmental exposures, each subject of the at-risk population has the same probability of death; d) environmental covariates have a common effect on mortality of all members of at-risk population; and e) the averages of individual risk factors, such as smoking habits, over the at-risk population vary smoothly with time. Under these conditions, the association between temporal variation in the environmental covariates and the survival experience of members of the dynamic population can be estimated by regressing the daily number of deaths on the daily value of the environmental covariates, as is done in time-series mortality studies. Issues in extrapolating risk estimates based on time-series studies in one population to estimate the amount of life lost in another population are also discussed. PMID:12842769

  1. Distant future of the Sun and Earth revisited

    E-print Network

    Klaus-Peter Schroder; Robert C. Smith

    2008-01-25

    We revisit the distant future of the Sun and the solar system, based on stellar models computed with a thoroughly tested evolution code. For the solar giant stages, mass-loss by the cool (but not dust-driven) wind is considered in detail. Using the new and well-calibrated mass-loss formula of Schroder & Cuntz (2005, 2007), we find that the mass lost by the Sun as an RGB giant (0.332 M_Sun, 7.59 Gy from now) potentially gives planet Earth a significant orbital expansion, inversely proportional to the remaining solar mass. According to these solar evolution models, the closest encounter of planet Earth with the solar cool giant photosphere will occur during the tip-RGB phase. During this critical episode, for each time-step of the evolution model, we consider the loss of orbital angular momentum suffered by planet Earth from tidal interaction with the giant Sun, as well as dynamical drag in the lower chromosphere. We find that planet Earth will not be able to escape engulfment, despite the positive effect of solar mass-loss. In order to survive the solar tip-RGB phase, any hypothetical planet would require a present-day minimum orbital radius of about 1.15 AU. Furthermore, our solar evolution models with detailed mass-loss description predict that the resulting tip-AGB giant will not reach its tip-RGB size. The main reason is the more significant amount of mass lost already in the RGB phase of the Sun. Hence, the tip-AGB luminosity will come short of driving a final, dust-driven superwind, and there will be no regular solar planetary nebula (PN). But a last thermal pulse may produce a circumstellar (CS) shell similar to, but rather smaller than, that of the peculiar PN IC 2149 with an estimated total CS shell mass of just a few hundredths of a solar mass.

  2. The intercomparison of ozone measured from the SME and Nimbus-7 satellites on short and long time scales

    NASA Technical Reports Server (NTRS)

    Chandra, S.; Mcpeters, R. D.; Srivastava, D. N.

    1986-01-01

    The spatial and temporal characteristics of ozone density measured from the SBUV (Solar Backscatter Ultraviolet) spectrometer on Nimbus-7 and the UV and the UV and the IR spectrometers on SME (Solar Mesosphere Explorer) are compared in the altitude region near 50 km where the three data sets overlap. Their temporal characteristics, when averaged over the same longitude range, are remarkably similar with respect to seasonal variations and short term fluctuations induced by transient planetary waves. The long term trends in the three data sets, however, differ significantly with each other. Over the three year period after 1982 ozone mixing ratio at 1 mb decreased by about 10 percent based on SEUV measurements but increased by 12 and 30 percent respectively based on SME-IR and SME-UV measurements. None of these estimates are consistent with the predicted decrease of about 2 percent based on solar UV flux and temperature changes during this period.

  3. Search for short time-scale periodicity in the X-ray flux of 4U1700-37

    NASA Technical Reports Server (NTRS)

    Branduardi, G.; Dupree, A. K.; Sanford, P. W.; Pollard, G. S. G.

    1979-01-01

    The existence of a short-term periodicity in the X-ray light curve of the binary system 4U1700-37 was investigated by recent Copernicus observations. 4U1700-37 was observed for two complete binary cycles in July, 1978, with a sampling interval of 86.5 sec which allowed for the detection of periodicities down to 3 min. No evidence of the periodicity which had been previously reported in the ranges 20 to 30 min or 90 to 100 min was found, nor was there any in other ranges down to 3 min, even when X-ray noise caused by intense flares on 4U1700-37 was taken into account. Possible explanations for the recent absence of periodicity are proposed.

  4. The P600-as-P3 hypothesis revisited: single-trial analyses reveal that the late EEG positivity following linguistically deviant material is reaction time aligned.

    PubMed

    Sassenhagen, Jona; Schlesewsky, Matthias; Bornkessel-Schlesewsky, Ina

    2014-10-01

    The P600, a late positive ERP component following linguistically deviant stimuli, is commonly seen as indexing structural, high-level processes, e.g. of linguistic (re)analysis. It has also been identified with the P3 (P600-as-P3 hypothesis), which is thought to reflect a systemic neuromodulator release facilitating behavioural shifts and is usually response time aligned. We investigated single-trial alignment of the P600 to response, a critical prediction of the P600-as-P3 hypothesis. Participants heard sentences containing morphosyntactic and semantic violations and responded via a button press. The elicited P600 was perfectly response aligned, while an N400 following semantic deviations was stimulus aligned. This is, to our knowledge, the first single-trial analysis of language processing data using within-sentence behavioural responses as temporal covariates. Results support the P600-as-P3 perspective and thus constitute a step towards a neurophysiological grounding of language-related ERPs. PMID:25151545

  5. Daily timed melatonin feedings mimic effects of short days on testis regression and cortisol in circulation in Siberian hamsters

    Microsoft Academic Search

    Sara M. Hiebert; Stephen A. Green; Steven M. Yellon

    2006-01-01

    This study tested the efficacy of timed oral administration of melatonin as an alternative both to invasive methods (daily injections, timed infusions) and to untimed oral administration in Siberian hamsters (Phodopus sungorus), an important model for the study of photoperiodism. Hamsters readily consumed a small piece of melatonin-treated apple immediately when presented and circulating melatonin was rapidly elevated with a

  6. Expression of Flowering-Time Genes in Soybean E1 Near-isogenic Lines Under Short and Long Day Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Control of soybean flowering time is important for geographic adaptation, and maximizing yield. Plant breeders have identified a series of genes (E genes) that condition time to flowering, however, the molecular basis in the control of flowering by these E genes, in conjunction with canonical flowe...

  7. 25 CFR 26.30 - Does the Job Training Program provide part-time training or short-term training?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Does the Job Training Program provide part-time training...DEPARTMENT OF THE INTERIOR HUMAN SERVICES JOB PLACEMENT AND TRAINING PROGRAM Training Services 26.30 Does the Job Training Program provide part-time...

  8. 25 CFR 26.30 - Does the Job Training Program provide part-time training or short-term training?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2011-04-01 true Does the Job Training Program provide part-time training...DEPARTMENT OF THE INTERIOR HUMAN SERVICES JOB PLACEMENT AND TRAINING PROGRAM Training Services 26.30 Does the Job Training Program provide part-time...

  9. 25 CFR 26.30 - Does the Job Training Program provide part-time training or short-term training?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Does the Job Training Program provide part-time training...DEPARTMENT OF THE INTERIOR HUMAN SERVICES JOB PLACEMENT AND TRAINING PROGRAM Training Services 26.30 Does the Job Training Program provide part-time...

  10. 25 CFR 26.30 - Does the Job Training Program provide part-time training or short-term training?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Does the Job Training Program provide part-time training...DEPARTMENT OF THE INTERIOR HUMAN SERVICES JOB PLACEMENT AND TRAINING PROGRAM Training Services 26.30 Does the Job Training Program provide part-time...

  11. Oxidative phosphorylation revisited.

    PubMed

    Nath, Sunil; Villadsen, John

    2015-03-01

    The fundamentals of oxidative phosphorylation and photophosphorylation are revisited. New experimental data on the involvement of succinate and malate anions respectively in oxidative phosphorylation and photophosphorylation are presented. These new data offer a novel molecular mechanistic explanation for the energy coupling and ATP synthesis carried out in mitochondria and chloroplast thylakoids. The mechanism does not suffer from the flaws in Mitchell's chemiosmotic theory that have been pointed out in many studies since its first appearance 50 years ago, when it was hailed as a ground-breaking mechanistic explanation of what is perhaps the most important process in cellular energetics. The new findings fit very well with the predictions of Nath's torsional mechanism of energy transduction and ATP synthesis. It is argued that this mechanism, based on at least 15 years of experimental and theoretical work by Sunil Nath, constitutes a fundamentally different theory of the energy conversion process that eliminates all the inconsistencies in Mitchell's chemiosmotic theory pointed out by other authors. It is concluded that the energy-transducing complexes in oxidative phosphorylation and photosynthesis are proton-dicarboxylic acid anion cotransporters and not simply electrogenic proton translocators. These results necessitate revision of previous theories of biological energy transduction, coupling, and ATP synthesis. The novel molecular mechanism is extended to cover ATP synthesis in prokaryotes, in particular to alkaliphilic and haloalkaliphilic bacteria, essentially making it a complete theory addressing mechanistic, kinetic, and thermodynamic details. Finally, based on the new interpretation of oxidative phosphorylation, quantitative values for the P/O ratio, the amount of ATP generated per redox package of the reduced substrates, are calculated and compared with experimental values for fermentation on different substrates. It is our hope that the presentation of oxidative phosphorylation and photophosphorylation from a wholly new perspective will rekindle scientific discussion of a key process in bioenergetics and catalyze new avenues of research in a truly interdisciplinary field. PMID:25384602

  12. Heliocentric Distance of Coronal Mass Ejections at the Time of Energetic Particle Release: Revisiting the Ground Level Enhancement Events of Solar Cycle 23

    NASA Technical Reports Server (NTRS)

    Gopalswamy, Natchimuthuk

    2011-01-01

    Using the kinematics of coronal mass ejections (CMEs), onset time of soft X-ray flares, and the finite size of the pre-eruption CME structure, we derive the heliocentric distane at which the energetic particles during the ground level enhancement (GLE) events of Solar Cycle 23. We find that the GLE particles are released when the CMEs reach an average heliocentric distance of approx.3.25 solar radii (Rs). From this we infer that the shocks accelerating the particles are located at similar heights. Type II radio burst observations indicate that the CMEs are at much lower distances (average approx.1.4 Rs) when the CME-driven shock first forms. The shock seems to travel approx.1.8 Rs over a period of approox.30 min on the average before releasing the GLE particles. In deriving these results, we made three assumptions that have observational support: (i) the CME lift off occurs from an initial distance of about 1.25 Rs; (ii) the flare onset and CME onset are one and the same because these are two different manifestations of the same eruption; and (iii) the CME has positive acceleration from the onset to the first appearance in the coronagraphic field of view (2.5 to 6 Rs). Observations of coronal cavities in eclipse pictures and in coronagraphic images justify the assumption (i). The close relationship between the flare reconnection magnetic flux and the azimuthal flux of interplanetary magnetic clouds justify assumption (ii) consistent with the standard model (CSHKP) of solar eruption. Coronagraphic observations made close to the solar surface indicate a large positive acceleration of CMEs to a heliocentric distance of approx.3 Rs before they start slowing down due to the drag force. The inferred acceleration (approx.1.5 km/s/s) is consistent with reported values in the literature.

  13. Distinguishing the monomer to cluster phase transition in concentrated lysozyme solutions by studying the temperature dependence of the short-time dynamics

    NASA Astrophysics Data System (ADS)

    Falus, Pter; Porcar, Lionel; Fratini, Emiliano; Chen, Wei-Ren; Faraone, Antonio; Hong, Kunlun; Baglioni, Piero; Liu, Yun

    2012-02-01

    Recent combined experiments by small angle neutron scattering (SANS) and neutron spin echo (NSE) have demonstrated that dynamic clusters can form in concentrated lysozyme solutions when the right combination of a short-ranged attraction and a long-ranged electrostatic repulsion exists. In this paper, we investigate the temperature effect on the dynamic cluster formation and try to pinpoint the transition concentration from a monomeric protein phase to a cluster phase. Interestingly, even at a relatively high concentration (10% mass fraction), despite the significant change in the SANS patterns that are associated with the change of the short-ranged attraction among proteins, the normalized short-time self-diffusion coefficient is not affected between 5 and 40?C. This is interpreted as a lack of cluster formation in this condition. However, at larger concentrations such as 17.5% and 22.5% mass fraction, we show that the average hydrodynamic radius increases significantly and causes a large decrease of the normalized self-diffusion coefficient as a result of cluster formation when the temperature is changed from 25 to 5?C.

  14. Optical design of the short pulse x-ray imaging and microscopy time-angle correlated diffraction beamline at the Advanced Photon Source

    SciTech Connect

    Reininger, R.; Dufresne, E. M.; Borland, M.; Beno, M. A.; Young, L.; Kim, K.-J. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Evans, P. G. [Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2013-05-15

    The short pulse x-ray imaging and microscopy beamline is one of the two x-ray beamlines that will take full advantage of the short pulse x-ray source in the Advanced Photon Source (APS) upgrade. A horizontally diffracting double crystal monochromator which includes a sagittally focusing second crystal will collect most of the photons generated when the chirped electron beam traverses the undulator. A Kirkpatrick-Baez mirror system after the monochromator will deliver to the sample a beam which has an approximately linear correlation between time and vertical beam angle. The correlation at the sample position has a slope of 0.052 ps/{mu}rad extending over an angular range of 800 {mu}rad for a cavity deflection voltage of 2 MV. The expected time resolution of the whole system is 2.6 ps. The total flux expected at the sample position at 10 keV with a 0.9 eV energy resolution is 5.7 Multiplication-Sign 10{sup 12} photons/s at a spot having horizontal and vertical full width at half maximum of 33 {mu}m horizontal by 14 {mu}m vertical. This new beamline will enable novel time-dispersed diffraction experiments on small samples using the full repetition rate of the APS.

  15. A measurement of the e/{pi} ratio difference between short (250 ns) and long (2.2 {mu}s) integration times with the D0 uranium-liquid argon central calorimeter

    SciTech Connect

    Pi, B.

    1992-12-31

    The difference of the ratios of the high energy electron and pion responses(e/{pi}) in the DO Uranium-liquid Argon central calorimeter is measured using the DO calorimeter trigger readout (short integration time: 250 ns) and precision readout (long integration time: 2.2 {mu}s). This measurement found a 5% difference in the e/{pi} ratio between short and long integration times, with estimated uncertainty of 2.3%.

  16. Thermal scene analysis via finite element model and finite difference time domain numerical solution of the electromagnetic wave propagation in the short wave and long wave infrared bandarch

    NASA Astrophysics Data System (ADS)

    Albertoni, Alessandro

    2009-09-01

    We utilize the Finite Element Model (FEM) and Finite Difference Time Domain (FDTD) numerical solution of the Electromagnetic wave propagation in the Short Wave Infrared (SWIR) and Long Wave Infrared (LWIR) bands in order to calculate the target radiance propagation and environment attenuation due to transmission, absorption and reflections in atmosphere and obstacles. We leave to traditional minimum resolvable temperature (MRTD) the model of the camera radiance collection (actual thermal sensitivity of the camera). The main advantage of the numerical propagation is that there is the possibility to model exactly the specific target shape and the specific environment (depending of the computational power) and calculate the residual temperature.

  17. Trends in ostracod distribution and water chemistry in subarctic Canada: Churchill (Manitoba) lakes and ponds revisited

    NASA Astrophysics Data System (ADS)

    Viehberg, F. A.; Ct, G.; Pienitz, R.

    2009-04-01

    Ecosystems change in response to factors such as climate variability, invasions, and natural hazards over a short period of time (IPCC 2007). The individual organism has to react to complete its life cycle and eventually to reproduce successfully. Under extreme conditions the survival of the total population depends thoroughly on the genetic diversity/potential and thus the ability to expand its biogeographical range or to run extinct. The knowledge of the specific plasticity in time is essential to interpret signals of biological proxies in palaeo records. We investigated 13 lakes/ponds in the surrounding of the Churchill Northern Studies Centre (CNSC; 58 43.989'N, 93 49.219'W), Churchill, Canada in 1997. 9 years later we revisited the same localities in 2006. In addition, faunistic data of microcrustaceans in the local study area is available from the late 80's (Havel et al 1990 a, b). and further instrumental climate records from Churchill (Manitoba, Canada) are daily filed since 1943 by Environment Canada. Thus we were able to pinpoint local warming trends and changes in the water chemistry from our short term records in the subarctic study area. The microcrustacean fauna change consecutively. e.g., freshwater ostracods adopted to short open water periods during the summer, strong variations of water temperatures in the shallow waters and mostly low ionic contents of the host waters are not present in the current record. References: Havel, J.E., Hebert, P.D.N. and Delorme, L.D., 1990a. Genetics of sexual Ostracoda from a low Arctic site. Journal of Evolutionary Biology, 3: 65-84. Havel, J.E., Hebert, P.D.N. and Delorme, L.D., 1990b. Genotypic diversity of asexual Ostracoda from a low Arctic site. Journal of Evolutionary Biology, 3: 391-410.

  18. Balance functions revisited

    E-print Network

    A. Bialas

    2011-02-11

    The idea of glue clusters, i.e. short-range correlations in the quark-gluon plasma close to freeze-out, is used to estimate the width of balance functions in momentum space. A good agreement is found with the recent measurements of STAR collaboration for central $Au-Au$ collisions.

  19. Time-resolved imaging with OKE-based time-gate: enhancement in spatial resolution using low-coherence ultra-short illumination

    E-print Network

    Purwar, Harsh; Roz, Claude; Blaisot, Jean-Bernard

    2015-01-01

    We propose a collinear optical Kerr effect (OKE) based time-gate configuration with low coherence illumination source, derived from the supercontinuum (SC) generated by focusing the femtosecond laser pulses inside water. At first the spectral broadening in SC generation and corresponding changes in its coherence properties are studied and then a narrow band of wavelengths is extracted to use as the probe beam in the OKE-based time-gate configuration. The gate timings and spatial resolution of the time-gated images are also investigated. The low coherence of the probe ensures that the artifacts due to speckles from the laser are reduced to a minimum. To illustrate this a comparison of the time-resolved images of the fuel sprays obtained with this configuration has been made with the images obtained with the collinear, dual color configuration of the optical gate with coherent illumination.

  20. Dynamic Topography Revisited

    NASA Astrophysics Data System (ADS)

    Moresi, Louis

    2015-04-01

    Dynamic Topography Revisited Dynamic topography is usually considered to be one of the trinity of contributing causes to the Earth's non-hydrostatic topography along with the long-term elastic strength of the lithosphere and isostatic responses to density anomalies within the lithosphere. Dynamic topography, thought of this way, is what is left over when other sources of support have been eliminated. An alternate and explicit definition of dynamic topography is that deflection of the surface which is attributable to creeping viscous flow. The problem with the first definition of dynamic topography is 1) that the lithosphere is almost certainly a visco-elastic / brittle layer with no absolute boundary between flowing and static regions, and 2) the lithosphere is, a thermal / compositional boundary layer in which some buoyancy is attributable to immutable, intrinsic density variations and some is due to thermal anomalies which are coupled to the flow. In each case, it is difficult to draw a sharp line between each contribution to the overall topography. The second definition of dynamic topography does seem cleaner / more precise but it suffers from the problem that it is not measurable in practice. On the other hand, this approach has resulted in a rich literature concerning the analysis of large scale geoid and topography and the relation to buoyancy and mechanical properties of the Earth [e.g. refs 1,2,3] In convection models with viscous, elastic, brittle rheology and compositional buoyancy, however, it is possible to examine how the surface topography (and geoid) are supported and how different ways of interpreting the "observable" fields introduce different biases. This is what we will do. References (a.k.a. homework) [1] Hager, B. H., R. W. Clayton, M. A. Richards, R. P. Comer, and A. M. Dziewonski (1985), Lower mantle heterogeneity, dynamic topography and the geoid, Nature, 313(6003), 541-545, doi:10.1038/313541a0. [2] Parsons, B., and S. Daly (1983), The relationship between surface topography, gravity anomalies, and temperature structure of convection, Journal of Geophysical Research: Solid Earth (1978-2012), 88(B2), 1129-1144, doi:10.1029/JB088iB02p01129. [3] Robinson, E. M., B. Parsons, and S. F. Daly (1987), The effect of a shallow low viscosity zone on the apparent compensation of mid-plate swells, Earth and Planetary Science Letters, 82(3-4), 335-348, doi:10.1016/0012-821X(87)90207-X.

  1. The study of time dependent, broadband X-ray emission from ultra-short pulse laser produced plasmas

    SciTech Connect

    Shepherd, R.; Booth, R.; Price, D.; Walling, R.; More, R.; Guethlein, G.; Young, B.; Dunn, J.; Osterheld, A.; Goldstein, W.; Stewart, R. (Lawrence Livermore National Laboratory, P.O. 808, Livermore, California 94550 (United States))

    1994-10-05

    The dynamics of X-ray spectra emitted by an ultrashort laser produced plasma is studied using a 100 fs 800 nm pulses. The broadband emission is used to estimate the time dependent plasma temperature. Experimental results are in a good agreement with hydrodynamic calculations. (AIP) [copyright] 1994 [ital American] [ital Institute] [ital of] [ital Physics

  2. Effects of Morning Caffeine Ingestion on Mood States, Simple Reaction Time, and Short-Term Maximal Performance on Elite Judoists

    PubMed Central

    Souissi, Makram; Abedelmalek, Salma; Chtourou, Hamdi; Atheymen, Rim; Hakim, Ahmed; Sahnoun, Zouhair

    2012-01-01

    Purpose The purpose of the present study was to evaluate the ergogenic effect of caffeine ingestion on mood state, simple reaction time, and muscle power during the Wingate test recorded in the morning on elite Judoists. Methods Twelve elite judoists (age: 21.08 1.16 years, body mass: 83.75 20.2 kg, height: 1.76 6.57 m) participated in this study. Mood states, simple reaction time, and muscle power during the Wingate test were measured during two test sessions at 07:00 h and after placebo or caffeine ingestion (i.e. 5 mg/kg). Plasma concentrations of caffeine were measured before (T0) and 1-h after caffeine ingestion (T1) and after the Wingate test (T3). Results Our results revealed an increase of the anxiety and the vigor (P<0.01), a reduction of the simple reaction time (P<0.001) and an improvement of the peak and mean powers during the Wingate test. However, the fatigue index during this test was unaffected by the caffeine ingestion. In addition, plasma concentration of caffeine was significantly higher at T1 in comparison with T0. Conclusions In conclusion, the results of this study suggest that morning caffeine ingestion has ergogenic properties with the potential to benefit performance, increase anxiety and vigor, and decrease the simple reaction time. PMID:23012635

  3. Effect of feature extraction for brain tumor classification based on short echo time 1H MR spectra

    Microsoft Academic Search

    J. Luts; J. B. Poullet; J. M. Garcia-Gomez; A. Heerschap; M. Robles; J. A. Suykens; S. van Huffel

    2008-01-01

    This study examines the effect of feature extraction methods prior to automated pattern recognition based on magnetic resonance spectroscopy (MRS) for brain tumor diagnosis. Since individual inspection of spectra is time-consuming and requires specific spectroscopic expertise, the introduction of clinical decision support systems (DSSs) is expected to strongly promote the clinical use of MRS. This study focuses on the feature

  4. The Genetic and Environmental Control of Reproductive Timing in a Short-Lived Monocarpic Species Daucus Carota (Umbelliferae)

    E-print Network

    Lacey, Elizabeth P.

    regimes in a growth chamber to measure the effects of nutrient supply and maternal age of flowering by delaying the year of reproduction if resources abound or by accelerating reproduction if resources become growth and reproductive timing in monocarpic plants. (3) Maternal age and nutrient supply influenced

  5. Analysis of the time-varying energy of brain responses to an oddball paradigm using short-term smoothed Wigner-Ville distribution.

    PubMed

    Ta?luk, M E; Cakmak, E D; Karaka?, S

    2005-04-30

    Cognitive brain responses to external stimuli, as measured by event related potentials (ERPs), have been analyzed from a variety of perspectives to investigate brain dynamics. Here, the brain responses of healthy subjects to auditory oddball paradigms, standard and deviant stimuli, recorded on an Fz electrode site were studied using a short-term version of the smoothed Wigner-Ville distribution (STSW) method. A smoothing kernel was designed to preserve the auto energy of the signal with maximum time and frequency resolutions. Analysis was conducted mainly on the time-frequency distributions (TFDs) of sweeps recorded during successive trials including the TFD of averaged single sweeps as the evoked time-frequency (ETF) brain response and the average of TFDs of single sweeps as the time-frequency (TF) brain response. Also the power entropy and the phase angles of the signal at frequency f and time t locked to the stimulus onset were studied across single trials as the TF power-locked and the TF phase-locked brain responses, respectively. TFDs represented in this way demonstrated the ERP spectro-temporal characteristics from multiple perspectives. The time-varying energy of the individual components manifested interesting TF structures in the form of amplitude modulated (AM) and frequency modulated (FM) energy bursts. The TF power-locked and phase-locked brain responses provoked ERP energies in a manner modulated by cognitive functions, an observation requiring further investigation. These results may lead to a better understanding of integrative brain dynamics. PMID:15814152

  6. The synchronous (time domain) average revisited

    NASA Astrophysics Data System (ADS)

    Braun, S.

    2011-05-01

    Synchronous averaging is one of the most powerful techniques for the extraction of periodic signals from a composite signal. It is based on averaging periodic sections, necessitating an a-priori knowledge of the period sought. It is one of the most effective signal processing tools applied to rotating machinery, and has been known and used for decades.It will be shown that synchronous average is actually just one of the many possible "synchronous filters" which could be used to extract the above periodic components performance. A novel signal analysis, geared to periodic signals will be introduced, with the potential of extracting more complex phenomena typical of some rotating machinery. Examples given are based on periodic oscillating transients, with various additive interferences. The possibility of additional signal processing approaches is also discussed.

  7. Increasing Short-Stay Unplanned Hospital Admissions among Children in England; Time Trends Analysis '97-`06

    Microsoft Academic Search

    Sonia Saxena; Alex Bottle; Ruth Gilbert; Mike Sharland; Pieter H. M. van Baal

    2009-01-01

    BackgroundTimely care by general practitioners in the community keeps children out of hospital and provides better continuity of care. Yet in the UK, access to primary care has diminished since 2004 when changes in general practitioners' contracts enabled them to opt out of providing out-of-hours care and since then unplanned pediatric hospital admission rates have escalated, particularly through emergency departments.

  8. Time course of lung retention and toxicity of inhaled particles: short-term exposure to nano-Ceria.

    PubMed

    Keller, Jana; Wohlleben, Wendel; Ma-Hock, Lan; Strauss, Volker; Grters, Sibylle; Kttler, Karin; Wiench, Karin; Herden, Christiane; Oberdrster, Gnter; van Ravenzwaay, Bennard; Landsiedel, Robert

    2014-11-01

    Two Ceria nanomaterials (NM-211 and NM-212) were tested for inhalation toxicity and organ burdens in order to design a chronic and carcinogenicity inhalation study (OECD TG No. 453). Rats inhaled aerosol concentrations of 0.5, 5, and 25mg/m(3) by whole-body exposure for 6h/day on 5 consecutive days for 1 or 4weeks with a post-exposure period of 24 or 129days, respectively. Lungs were examined by bronchoalveolar lavage and histopathology. Inhaled Ceria is deposited in the lung and cleared with a half-time of 40days; at aerosol concentrations higher than 0.5mg/m(3), this clearance was impaired resulting in a half-time above 200days (25mg/m(3)). After 5days, Ceria (>0.5mg/m(3)) induced an early inflammatory reaction by increases of neutrophils in the lung which decreased with time, with sustained exposure, and also after the exposure was terminated (during the post-exposure period). The neutrophil number observed in bronchoalveolar lavage fluid (BALF) was decreasing and supplemented by mononuclear cells, especially macrophages which were visible in histopathology but not in BALF. Further progression to granulomatous inflammation was observed 4weeks post-exposure. The surface area of the particles provided a dose metrics with the best correlation of the two Ceria's inflammatory responses; hence, the inflammation appears to be directed by the particle surface rather than mass or volume in the lung. Observing the time course of lung burden and inflammation, it appears that the dose rate of particle deposition drove an initial inflammatory reaction by neutrophils. The later phase (after 4weeks) was dominated by mononuclear cells, especially macrophages. The progression toward the subsequent granulomatous reaction was driven by the duration and amount of the particles in the lung. The further progression of the biological response will be determined in the ongoing long-term study. PMID:25273020

  9. Real-time operating mode with DSSSD detector to search for short correlation ER-alpha chains

    E-print Network

    Yury Tsyganov; Alexander Polyakov

    2015-06-05

    Real-time PC based algorithm is developed for DSSSD detector. Complete fusion nuclear reaction natYb+48Ca->217Th is used to test this algorithm at 48Ca beam. Example of successful application of a former algorithm for resistive strip PIPS detector in 249Bk+48Ca nuclear reaction is presented too. Case of alpha-alpha correlations is also under brief consideration.

  10. Real-time operating mode with DSSSD detector to search for short correlation ER-alpha chains

    E-print Network

    Tsyganov, Yury

    2015-01-01

    Real-time PC based algorithm is developed for DSSSD detector. Complete fusion nuclear reaction natYb+48Ca->217Th is used to test this algorithm at 48Ca beam. Example of successful application of a former algorithm for resistive strip PIPS detector in 249Bk+48Ca nuclear reaction is presented too. Case of alpha-alpha correlations is also under brief consideration.

  11. The Effects of Timing of Pediatric Knee Ligament Surgery on Short-term Academic Performance in School-Aged Athletes

    Microsoft Academic Search

    Natasha E. Trentacosta; Mark A. Vitale; Christopher S. Ahmad

    2009-01-01

    Background: Orthopaedic injuries negatively affect the academic lives of children.Hypothesis: The timing of anterior cruciate ligament (ACL) and medial patellofemoral ligament (MPFL) reconstructions affects academic performance in school-aged athletes.Study Design: Cohort study; Level of evidence, 2.Methods: Records of patients ?18 years old who underwent ACL or MPFL reconstructions from 2001-2007 were reviewed retrospectively. Subjects had been administered a unique questionnaire

  12. Making Productive Use of Four Models of School English: A Case Study Revisited

    ERIC Educational Resources Information Center

    Macken-Horarik, Mary

    2014-01-01

    At a time when political leaders and media pundits seek to narrow the English curriculum and reduce its knowledge structure to the "basics," it is helpful to revisit the potential of different approaches to learning in English that have evolved over time. In this paper I reflect on the semantic features of personal growth, cultural

  13. Predictability of Solar Radiation for Photovoltaics systems over Europe: from short-term to seasonal time-scales

    NASA Astrophysics Data System (ADS)

    De Felice, Matteo; Petitta, Marcello; Ruti, Paolo

    2014-05-01

    Photovoltaic diffusion is steadily growing on Europe, passing from a capacity of almost 14 GWp in 2011 to 21.5 GWp in 2012 [1]. Having accurate forecast is needed for planning and operational purposes, with the possibility to model and predict solar variability at different time-scales. This study examines the predictability of daily surface solar radiation comparing ECMWF operational forecasts with CM-SAF satellite measurements on the Meteosat (MSG) full disk domain. Operational forecasts used are the IFS system up to 10 days and the System4 seasonal forecast up to three months. Forecast are analysed considering average and variance of errors, showing error maps and average on specific domains with respect to prediction lead times. In all the cases, forecasts are compared with predictions obtained using persistence and state-of-art time-series models. We can observe a wide range of errors, with the performance of forecasts dramatically affected by orography and season. Lower errors are on southern Italy and Spain, with errors on some areas consistently under 10% up to ten days during summer (JJA). Finally, we conclude the study with some insight on how to "translate" the error on solar radiation to error on solar power production using available production data from solar power plants. [1] EurObserver, "Baromtre Photovoltaque, Le journal des nergies renouvables, April 2012."

  14. Decomposing very rapid crustal displacements observed in the Amundsen Embayment into their instantaneous elastic and short (10-100 yr) time-scale viscoelastic components

    NASA Astrophysics Data System (ADS)

    Barletta, Valentina; Bevis, Michael; Smith, Ben; Wilson, Terry J.; Brown, Abel; Bordoni, Andrea; Willis, Michael; Smalley, Bob; Kendrick, Eric; Konfal, Stephanie; Caccamise, Dana; Aster, Richard; Chaput, Julien; Heeszel, David; Lloyd, Andrew; Wiens, Doug

    2015-04-01

    The Amundsen Embayment sector of West Antarctica is experiencing some of the fastest sustained bedrock uplift rates in the world. These motions, recorded by the Antarctic GPS Network (ANET) are far too rapid to be explained using traditional GIA models, but they cannot be explained purely in terms of the Earth's elastic response to contemporary ice loss. We use 13 years of very high resolution DEM-derived ice mass change fields over the Amundsen sector to compute the elastic signal and remove that from the observed geodetic time series. We obtain a very large residual - up to 5 times larger than the computed elastic response. We hypothesize that this residual signal manifests a short-time-scale viscoelastic response to post- Little Ice Age ice mass changes, including ice losses developed in the last decade or so. Short time-scale, high-rate viscoelastic deformation is plausible in areas underlain by very low mantle viscosities. Low or very low mantle viscosities are expected in this area based on existing heat flow estimates, seismic velocity anomalies, thin crust, and active volcanism, all of which are associated with geologically recent rifting. We estimated a plausible ice history for the last hundred years. We used the actual measurements from 2002 to 2014, and before 2002 we use 25% of present day melting rate, as suggested by published studies. We then simulated the bedrock displacement - both vertical and horizontal - with a spherical compressible viscoelastic Earth model having a low viscosity shallow upper mantle. We show that we can explain most of the signal (amplitude and direction) by using a 50-60 km elastic lithosphere and 1-2 x10^18 Pa s viscosity in the shallow upper mantle.

  15. Revisiting niacin: reviewing the evidence

    Microsoft Academic Search

    Christopher S. Vaccari; Ramadan A. Hammoud; Sameer H. Nagamia; Kanni Ramasamy; Allen L. Dollar; Bobby V. Khan

    2007-01-01

    Atherogenic dyslipidemia, defined by a cluster of lipoprotein abnormalities, including low high?density lipoprotein cholesterol (HDL-C) and elevated serum triglycerides, represents an important potential target for reducing cardiovascular risk. This has paved the way for revisiting niacin as a therapy in preventing progression of atherosclerosis. Niacin remains the safest and most effective agent for raising HDL-C and is a logical choice

  16. A simple model for the short-time evolution of near-surface current and temperature profiles

    NASA Astrophysics Data System (ADS)

    Jenkins, Alastair D.; Ward, Brian

    2005-05-01

    A simple analytical/numerical model has been developed for computing the evolution, over periods of up to a few hours, of the current and temperature profile in the upper layer of the ocean. The model is based upon conservation laws for heat and momentum, and employs an eddy diffusion parameterisation which is dependent on both the wind speed and the wind stress applied at the sea surface. Other parameters such as the bulk-skin surface temperature difference and CO 2 flux are determined by application of the Molecular Oceanic Boundary Layer Model (MOBLAM) of Schlssel and Soloviev. A similar model, for the current profile only, predicts a temporary increase in wave breaking intensity and decrease in wave height under conditions where the wind speed increases suddenly, such as, for example, during gusts and squalls. The model results are compared with measurements from the Lagrangian Skin Depth Experimental Profiler (SkinDeEP) surface profiling instrument made during the 1999 MOCE-5 field experiment in the waters around Baja California. SkinDeEP made repeated profiles of temperature within the upper few metres of the water column. Given that no tuning was performed in the model, and that the model does not take account of stratification, the results of the model runs are in rather good agreement with the observations. The model may be suitable as an interface between time-independent models of processes very near the surface, and larger-scale three-dimensional time-dependent ocean circulation models. A straightforward extension of the model should also be capable of making time-dependent computations of gas concentration in the near-surface layer of the ocean.

  17. Very short NMR relaxation times of anions in ionic liquids: New pulse sequence to eliminate the acoustic ringing

    NASA Astrophysics Data System (ADS)

    Klimavicius, Vytautas; Gdaniec, Zofia; Balevicius, Vytautas

    2014-11-01

    NMR relaxation processes of anions were studied in two neat imidazolium-based room temperature ionic liquids (RTILs) 1-decyl-3-methyl-imidazolium bromide- and chloride. The spin-lattice and spin-spin relaxations of 81Br and 35Cl nuclei were found to be extremely fast due to very strong quadrupolar interactions. The determined relaxation rates are comparable with those observed in the solids or in some critical organic solute/water/salt systems. In order to eliminate the acoustic ringing of the probe-head during relaxation times measurements the novel pulse sequence has been devised. It is based on the conventional inversion recovery pulse sequence, however, instead of the last 90 pulse the subsequence of three 90 pulses applied along axes to fulfill the phase cycling condition is used. Using this pulse sequence it was possible to measure T1 for both studied nuclei. The viscosity measurements have been carried out and the rotational correlation times were calculated. The effective 35Cl quadrupolar coupling constant was found to be almost one order lower than that for 81Br, i.e. 1.8 MHz and 16.0 MHz, respectively. Taking into account the facts that the ratio of (Q(35Cl)/Q(81Br))2 ? 0.1 and EFG tensors on the anions are quite similar, analogous structural organizations are expected for both RTILs. The observed T1/T2 (1.27-1.44) ratios were found to be not sufficiently high to confirm the presence of long-living (on the time scale of ?10-8 s) mesoscopic structures or heterogeneities in the studied neat ionic liquids.

  18. Short GRB 130603B: Discovery of a jet break in the optical and radio afterglows, and a mysterious late-time X-ray excess

    SciTech Connect

    Fong, W.; Berger, E.; Margutti, R.; Chornock, R.; Migliori, G.; Zauderer, B. A.; Lunnan, R.; Laskar, T. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Metzger, B. D. [Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Foley, R. J. [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801 (United States); Desch, S. J. [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287-1404 (United States); Meech, K. J.; Sonnett, S. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Dickey, C.; Hedlund, A. [Pomona College, 610 N. College Ave., Claremont, CA 91711 (United States); Harding, P. [Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106-7215 (United States)

    2014-01-10

    We present radio, optical/NIR, and X-ray observations of the afterglow of the short-duration Swift and Konus-Wind GRB 130603B, and uncover a break in the radio and optical bands at ?0.5 day after the burst, best explained as a jet break with an inferred jet opening angle of ?4-8. GRB 130603B is only the third short GRB with a radio afterglow detection to date, and represents the first time that a jet break has been evident in the radio band. We model the temporal evolution of the spectral energy distribution to determine the burst explosion properties and find an isotropic-equivalent kinetic energy of ?(0.6-1.7) 10{sup 51} erg and a circumburst density of ?5 10{sup 3}-30 cm{sup 3}. From the inferred opening angle of GRB 130603B, we calculate beaming-corrected energies of E {sub ?} ? (0.5-2) 10{sup 49} erg and E {sub K} ? (0.1-1.6) 10{sup 49} erg. Along with previous measurements and lower limits we find a median opening angle of ?10. Using the all-sky observed rate of 10 Gpc{sup 3} yr{sup 1}, this implies a true short GRB rate of ?20 yr{sup 1} within 200 Mpc, the Advanced LIGO/VIRGO sensitivity range for neutron star binary mergers. Finally, we uncover evidence for significant excess emission in the X-ray afterglow of GRB 130603B at ? 1 day and conclude that the additional energy component could be due to fall-back accretion or spin-down energy from a magnetar formed following the merger.

  19. Changes in Childrens Perception-Action Tuning over Short Time Scales: Bicycling across Traffic-Filled Intersections in a Virtual Environment

    PubMed Central

    Plumert, Jodie M.; Kearney, Joseph K.; Cremer, James F.; Recker, Kara M.; Strutt, Jonathan

    2010-01-01

    This investigation examined short-term changes in child and adult cyclists gap decisions and movement timing in response to general and specific road-crossing experiences. Ten- and 12-year-olds and adults rode a bicycle through a virtual environment with 12 intersections. Participants faced continuous cross traffic and waited for gaps they judged were adequate for crossing. In the control condition, participants encountered randomly ordered gaps ranging from 1.5 to 5 s at all intersections. In the high-density condition, participants encountered high-density intersections sandwiched between sets of control intersections. These high-density intersections were designed to push participants toward taking tighter gaps. Participants in both conditions were more likely to accept 3.5, 4, 4.5, and 5 s gaps during the last than the first set of intersections, whereas participants in the high-density condition were also more likely to accept very tight 3 s gaps at the last than the first set of intersections. Moreover, individuals in the high-density condition who waited less and took shorter gaps during the middle intersections were also more likely to take very tight 3 s gaps during the last intersections. Ten-year-olds in both conditions had more time to spare when they cleared the path of the oncoming car at the last intersections, whereas 12-year-olds and adults showed no change in time to spare across intersections. Discussion focuses on linking short-term change in perceptual-motor functioning to longer-term perceptual-motor development. PMID:20728090

  20. The short-time structural plasticity of dendritic spines is altered in a model of Rett syndrome

    PubMed Central

    Landi, Silvia; Putignano, Elena; Boggio, Elena Maria; Giustetto, Maurizio; Pizzorusso, Tommaso; Ratto, Gian Michele

    2011-01-01

    The maturation of excitatory transmission comes about through a developmental period in which dendritic spines are highly motile and their number, form and size are rapidly changing. Surprisingly, although these processes are crucial for the formation of cortical circuitry, little is known about possible alterations of these processes in brain disease. By means of acute in vivo 2-photon imaging we show that the dynamic properties of dendritic spines of layer V cortical neurons are deeply affected in a mouse model of Rett syndrome (RTT) at a time around P25 when the neuronal phenotype of the disease is still mild. Then, we show that 24h after a subcutaneous injection of IGF-1 spine dynamics is restored. Our study demonstrates that spine dynamics in RTT mice is severely impaired early during development and suggest that treatments for RTT should be started very early in order to reestablish a normal period of spine plasticity. PMID:22355564

  1. Measuring inorganic nitrate species with short time resolution from an aircraft platform by dual-channel ozone chemiluminescence

    NASA Astrophysics Data System (ADS)

    Tanner, Roger L.; Valente, Ralph J.; Meagher, James F.

    1998-09-01

    A measurement technique for determining nitrate (the sum of nitric acid and particulate nitrate) with a few seconds time resolution in plumes is needed to resolve within-plume features. A technique using dual ozone-chemiluminescent NO detectors with a selective nitrate scrubber in one sampling train is promising if used with an appropriate sampling inlet, and if nitrate is the desired analyte. We report the design of, and preliminary results from a dual channel ozone-chemiluminescent system, each channel containing a gold-CO catalyzed converter which reduces all odd nitrogen species (NOy) quantitatively to NO; one channel also contains a nylon filter to remove nitrate from the air stream prior to the converter (this signal is termed NOy*). This system was deployed successfully in a Bell 205 helicopter during the 1995 Southern Oxidants Study Nashville Ozone Study. The converters were mounted forward near the air intake, and zero air and calibration gases admitted simultaneously to both channels during flight operations. The difference signal between the two channels (NOy-NOy*) indicated apparent nitrate levels in the sampled air with a time resolution of <5 s and a limit of detection of about 1 ppbv. Nitrate levels observed with this system in plumes and background air during the Nashville Ozone Study were highly correlated with ozone and varied from below detection limits to ?20 ppbv. Nitrate levels were also highly correlated with the calculated difference between NOy and the sum of NO and NO2 (NOz). Higher nitrate levels as a fraction of NOz were found in power plant plumes (?60%) compared with urban plumes (?50%) and background air, consistent with apparently lower ozone production efficiencies in power plant plumes vis--vis urban plumes.

  2. Short Time-Scale Enhancements to the Global Thermosphere Temperature and Nitric Oxide Content Resulting From Ionospheric Joule Heating

    NASA Astrophysics Data System (ADS)

    Weimer, D. R.; Mlynczak, M. G.; Hunt, L. A.; Sutton, E. K.

    2014-12-01

    The total Joule heating in the polar ionosphere can be derived from an empirical model of the electric fields and currents, using input measurements of the solar wind velocity and interplanetary magnetic field (IMF). In the thermosphere, measurements of the neutral density from accelerometers on the CHAMP and GRACE satellites are used to derive exospheric temperatures, showing that enhanced ionospheric energy dissipation produces elevated temperatures with little delay.Using the total ionospheric heating, changes in the global mean exosphere temperature as a function of time can be calculated with a simple differential equation. The results compare very well with the CHAMP and GRACE measurement. A critical part of the calculation is the rate at which the thermosphere cools after the ionospheric heating is reduced. It had been noted previously that events with significant levels of heating subsequently cool at a faster rate, and this cooling was attributed to enhanced nitric oxide emissions. This correlation with nitric oxide has been confirmed with very high correlations with measurements of nitric oxide emissions in the thermosphere, from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. These measurements were used in a recent improvement in the equations that calculate the thermosphere temperature. The global nitric oxide cooling rates are included in this calculation, and the predicted levels of nitric oxide, derived from the ionosphere heating model, match the SABER measurements very well, having correlation coefficients on the order of 0.9.These calculations are used to govern the sorting of measurements CHAMP and GRACE measurements, on the basis of the global temperature enhancements due to Joule heating, as well as various solar indices, and season. Global maps of the exospheric temperature are produced from these sorted data.

  3. Long- and Short-Time Scale Glacial Isostasy of the Antarctic Peninsula and Impact on GRACE Science

    NASA Astrophysics Data System (ADS)

    Ivins, E. R.; James, T. S.; Wu, X.

    2009-04-01

    The ice cover grounded to the Antarctic Peninsula (AP) today represents but a small fraction of water attached to the continent of Antarctica (? 0.3 % by mass). However, the more northern latitude of the Peninsula renders its grounded water mass many times more volatile that is ice mass locked in the thick ice sheet cover south of 70-75? S. If ice on the entire Peninsula were to waste into the oceans it would cause 0.18 0.03 meters of sea-level rise (m.s.l.r.), large (~ 6 - 7 x) in comparison to the total sea-level equivalent holding capacity of Patagonian ice masses, but quite small in comparison to West Antarctica south of 75? S (? 1/25th). The amplitude of the Peninsula's annual water cycle is also anomalous: ? 0.5 Terra tones per year (Tt / yr, 1 Tt = 1012tones) or roughly a 1.39 mm / yr sea-level equivalent. While there is evidence that the Peninsula glaciers have been in retreat due to regional atmospheric and oceanic warming for the past half-century (Cook et al., 2005), or more, there has been a more recent acceleration of ice streams due to the loss of ice shelf buttressing in Graham Land. Rignot et al. (2008) determined that ice stream accelerations imply a 50-60% increase in the rate of ice loss from West Antarctica since 1996 to a level of about 0.132 Tt / yr, possibly accounting for 1/3 - 1/8th of the global non-steric sea-level rise (e.g., Cazenave et al., 2008). Estimates of Peninsula loss have risen even more dramatically and after 2005 are near 0.06 Tt / yr (Pritchard and Vaughan 2007; Rignot et al., 2008) As is the case for the smaller outlet glacier of southern Greenland (e.g., Howat et al. 2008), smaller glaciers of the AP are capable of responding to climate change on a relatively rapid time scale in comparison to continental ice sheets. In as much as the mass of AP collapse now appears ever more prominently in GRACE time-variable gravity data, and as a destablizing shelf-unbuttressing of tide water glaciers now drifts southward (e.g., Smith et al. 2007; Khazendar et al. 2007), it is important to place bounds on the secular gravitational signature of solid Earth viscoelastic isostatic flow. We examine recent developments in regional paleogeomorphologic and glacial history together with a broad range of earth parameters. For the regional slab window environment it is a safe assumption that the upper mantle viscosity is a factor of 2 or more reduced below that of Fennoscandia (Klemann et al., 2007). The water mass equivalent of the isostatic bedrock response is investigated thoroughly, as are numerical experiments in which quasi-exponential ice loss is assumed during the next century.

  4. Constraints on long-lived remnants of neutron star binary mergers from late-time radio observations of short duration gamma-ray bursts

    NASA Astrophysics Data System (ADS)

    Metzger, Brian D.; Bower, Geoffrey C.

    2014-01-01

    The coalescence of a binary neutron star (NS) system (an `NS merger' or NSM) may in some cases produce a massive NS remnant that is long lived and, potentially, indefinitely stable to gravitational collapse. Such a remnant has been proposed as an explanation for the late-X-ray emission observed following some short-duration gamma-ray bursts (GRBs) and as possible electromagnetic counterparts to the gravitational wave chirp. A stable NS merger remnant necessarily possesses a large rotational energy ?1052 erg, the majority of which is ultimately deposited into the surrounding circumburst medium (CBM) at mildly relativistic velocities. We present Very Large Array radio observations of seven short GRBs, some of which possessed temporally extended X-ray emission, on time-scales of 1-3 yr following the initial burst. No radio sources were detected, with typical upper limits 0.3 mJy at ? = 1.4 GHz. A basic model for the synchrotron emission from the blast wave is used to constrain the presence of a long-lived NSM remnant in each system. Depending on the GRB, our non-detections translate into upper limits on the CBM density n ? 3 10- 2-3 cm-3 required for consistency with the remnant hypothesis. Our upper limits rule out a long-lived remnant in GRB 050724 and 060505, but cannot rule out such a remnant in other systems due to their lower inferred CMB densities based on afterglow modelling or the lack of such constraints.

  5. Using Time Series of Landsat Data to Improve Understanding of Short- and Long-Term Changes to Vegetation Phenology in Response to Climate Change

    NASA Astrophysics Data System (ADS)

    Friedl, M. A.; Melaas, E. K.; Sulla-menashe, D. J.; Gray, J. M.

    2014-12-01

    Phenology, the seasonal progression of organisms through stages of dormancy, active growth, and senescence is a key regulator of ecosystem processes and is widely used as an indicator of vegetation responses to climate change. This is especially true in temperate forests, where seasonal dynamics in canopy development and senescence are tightly coupled to the climate system. Despite this, understanding of climate-phenology interactions is incomplete. A key impediment to improving this understanding is that available datasets are geographically sparse, and in most cases include relatively short time series. Remote sensing has been widely promoted as a useful tool for studies of large-scale phenology, but long-term studies from remote sensing have been limited to AVHRR data, which suffers from limitations related to its coarse spatial resolution and uncertainties in atmospheric corrections and radiometric adjustments that are used to create AVHRR time series. In this study, we used 30 years of Landsat data to quantify the nature and magnitude of long-term trends and short-term variability in the timing of spring leaf emergence and fall senescence. Our analysis focuses on temperate forest locations in the Northeastern United States that are co-located with surface meteorological observations, where we have estimated the timing of leaf emergence and leaf senescence at annual time steps using atmospherically corrected surface reflectances from Landsat TM and ETM+ imagery. Comparison of results from Landsat against ground observations demonstrates that phenological events can be reliably estimated from Landsat time series. More importantly, results from this analysis suggest two main conclusions related to the nature of climate change impacts on temperate forest phenology. First, there is clear evidence of trends towards longer growing seasons in the Landsat record. Second, interannual variability is large, with average year-to-year variability exceeding the magnitude of total changes to the growing season that have occurred over the last three decades. Based on these results we suggest that year-to-year variability in phenology, rather than long-term trends, provides the best basis for predicting future changes in temperate forest phenology in response to climate change.

  6. Short-term Assessment of Optimal Timing for Postoperative Rehabilitation after Flexor Digitorum Profundus Tendon Repair in a Canine Model

    PubMed Central

    Zhao, Chunfeng; Amadio, Peter C.; Tanaka, Tatsuro; Yang, Chao; Ettema, Anke M.; Zobitz, Mark E.; An, Kai-Nan

    2005-01-01

    The purpose of this study was to compare the shortterm outcome following flexor tendon repair for postoperative rehabilitation commencing on day 1 (a common clinical choice) versus day 5 (the day on which, with postoperative immobilization, the initial gliding resistance is least in this model) in an in vivo canine model. Work of flexion (WOF) and tendon strength were evaluated following tendon laceration and repair in 24 dogs sacrificed 10 days postoperatively. Starting postoperative mobilization at day 5 resulted in no tendon ruptures compared with tendon ruptures in four of the dogs (33%) in the group subjected to mobilization starting at day 1. While there was no statistically significant difference in WOF between groups at day 10, there was a trend toward lower resistance favoring the day 5 start group, and the statistical power to detect a difference in WOF was diminished by the ruptures in the day 1 group. We conclude that starting rehabilitation on day 5, when initial gliding resistance is lower, may have an advantage over earlier starting times, when surgical edema and other factors increase the initial force requirements to initiate tendon gliding. We plan further studies to evaluate the longer-term benefits of this rehabilitation program. PMID:16059853

  7. Containment failure time and mode for a low-pressure short-term station blackout in a BWR-4 with Mark-I containment

    SciTech Connect

    Carbajo, J.J.; Greene, S.R. (Oak Ridge National Lab., TN (United States))

    1993-01-01

    This study investigates containment failure time and mode for a low-pressure, short-term station blackout severe accident sequence in a boiling water reactor (BWR-4) with a Mark-I containment. The severe accident analysis code MELCOR, version 1.8.1, was used in these calculations. Other results using the MELCOR/CORBH package and the BWRSAR and CONTAIN codes are also presented and compared to the MELCOR results. The plant analyzed is the Peach Bottom atomic station, a BWR-4 with a Mark-I containment. The automatic depressurization system was used to depressurize the vessel in accordance with the Emergency Procedure Guidelines. Two different variations of the station blackout were studied: one with a dry cavity and the other with a flooded cavity. For the flooded cavity, it is assumed that a control rod drive (CRD) pump becomes operational after vessel failure, and it is used to pump water into the cavity.

  8. Surface properties of nitrided layer on AISI 316L austenitic stainless steel produced by high temperature plasma nitriding in short time

    NASA Astrophysics Data System (ADS)

    Li, Yang; Wang, Zhuo; Wang, Liang

    2014-04-01

    It has generally been believed that the formation of the S phase or expanded austenite ?N with enough thickness depends on the temperature (lower than 480 C) and duration of the process. In this work, we attempt to produce nitrogen expanded austenite layer at high temperature in short time. Nitriding of AISI 316L austenitic stainless steel was carried out at high temperatures (>520 C) for times ranging from 5 to 120 min. The microstructures, chemical composition, the thickness and the morphology of the nitrided layer, as well as its surface hardness, were investigated using X-ray diffraction, X-ray photoelectron spectroscopy, optical microscopy, scanning electron microscopy, and microhardness tester. The corrosion properties of the untreated and nitrided samples were evaluated using anodic polarization tests in 3.5% NaCl solution. The results confirmed that nitrided layer was shown to consist of ?N and a small amount of free-CrN and iron nitrides. High temperature plasma nitriding not only increased the surface hardness but also improved the corrosion resistance of the austenitic stainless steel, and it can critically reduce processing time compared with low temperature nitriding.

  9. Demospongic Acids Revisited

    PubMed Central

    Kornprobst, Jean-Michel; Barnathan, Gilles

    2010-01-01

    The well-known fatty acids with a ?5,9 unsaturation system were designated for a long period as demospongic acids, taking into account that they originally occurred in marine Demospongia sponges. However, such acids have also been observed in various marine sources with a large range of chain-lengths (C16C32) and from some terrestrial plants with short acyl chains (C18C19). Finally, the ?5,9 fatty acids appear to be a particular type of non-methylene-interrupted fatty acids (NMA FAs). This article reviews the occurrence of these particular fatty acids in marine and terrestrial organisms and shows the biosynthetic connections between ?5,9 fatty acids and other NMI FAs. PMID:21116406

  10. Foraging destinations and marine habitat use of short-tailed albatrosses: A multi-scale approach using first-passage time analysis

    USGS Publications Warehouse

    Suryan, R.M.; Sato, F.; Balogh, G.R.; David, Hyrenbach K.; Sievert, P.R.; Ozaki, K.

    2006-01-01

    We used satellite telemetry, remotely sensed data (bathymetry, chlorophyll a (chl a), sea-surface temperature (SST), wind speed) and first-passage time (FPT) analysis to determine the distribution, movement patterns, and habitat associations of short-tailed albatrosses (Phoebastria albatrus) during the non-breeding season, 2002 and 2003. Satellite transmitters were deployed on birds immediately prior to their departure from a breeding colony at Torishima, Japan (n = 11), or at-sea in the Aleutian Islands (n = 3). Tracking durations ranged from 51 to 138 days for a total of 6709 locations after filtering (131 - 808 per bird). FPT (time required to transit a circle of given radius) revealed the location and spatial scale of area-restricted search (ARS) patterns along flight paths. On average, ARS occurred within 70 km radii. Consequently, the fit of the habitat use models increased at spatial scales beyond a 40 km FPT radius (R2 = 0.31) and stabilized for scales of 70 km and larger (R2=0.40- 0.51). At all scales, wind speed, depth or depth gradient, and chl a or chl a gradient had a significant effect on FPT (i.e., residence time). FPT increased within regions of higher gradients of depth and chl a. In contrast, FPT decreased within regions of greater depth and wind speed, with a significant interaction of wind speed and depth at some scales. Sea-surface temperature or its interactions were only significant at large spatial scales (???160 km FPT radius). Albatrosses engaged in ARS activities primarily over the shelf break and slope, including Kuroshio and Oyashio regions off the western subarctic gyre. Occasionally, birds transited the northern boundary of the Kuroshio Extension while in-route to the Aleutian Islands and Bering Sea, but overall spent little time in the western gyre. In the Aleutian Islands, ARS occurred within straits, particularly along the central and western part of the archipelago. In the Bering Sea, ARS occurred along the northern continental shelf break, the Kamchatka Current region, and east of the Commander Islands. Non-breeding short-tailed albatross concentrate foraging in oceanic areas characterized by gradients in topography and water column productivity. This study provides an understanding of the foraging ecology for a highly migratory, imperiled seabird, and confirms the importance of shelf break and slope regions as hot spots for a variety of top marine predators in the North Pacific.

  11. Foraging destinations and marine habitat use of short-tailed albatrosses: A multi-scale approach using first-passage time analysis

    NASA Astrophysics Data System (ADS)

    Suryan, Robert M.; Sato, Fumio; Balogh, Gregory R.; David Hyrenbach, K.; Sievert, Paul R.; Ozaki, Kiyoaki

    2006-02-01

    We used satellite telemetry, remotely sensed data (bathymetry, chlorophyll a (chl a), sea-surface temperature (SST), wind speed) and first-passage time (FPT) analysis to determine the distribution, movement patterns, and habitat associations of short-tailed albatrosses ( Phoebastria albatrus) during the non-breeding season, 2002 and 2003. Satellite transmitters were deployed on birds immediately prior to their departure from a breeding colony at Torishima, Japan ( n=11), or at-sea in the Aleutian Islands ( n=3). Tracking durations ranged from 51 to 138 days for a total of 6709 locations after filtering (131 - 808 per bird). FPT (time required to transit a circle of given radius) revealed the location and spatial scale of area-restricted search (ARS) patterns along flight paths. On average, ARS occurred within 70 km radii. Consequently, the fit of the habitat use models increased at spatial scales beyond a 40 km FPT radius ( R2=0.31) and stabilized for scales of 70 km and larger ( R2=0.40- 0.51). At all scales, wind speed, depth or depth gradient, and chl a or chl a gradient had a significant effect on FPT (i.e., residence time). FPT increased within regions of higher gradients of depth and chl a. In contrast, FPT decreased within regions of greater depth and wind speed, with a significant interaction of wind speed and depth at some scales. Sea-surface temperature or its interactions were only significant at large spatial scales (?160 km FPT radius). Albatrosses engaged in ARS activities primarily over the shelf break and slope, including Kuroshio and Oyashio regions off the western subarctic gyre. Occasionally, birds transited the northern boundary of the Kuroshio Extension while in-route to the Aleutian Islands and Bering Sea, but overall spent little time in the western gyre. In the Aleutian Islands, ARS occurred within straits, particularly along the central and western part of the archipelago. In the Bering Sea, ARS occurred along the northern continental shelf break, the Kamchatka Current region, and east of the Commander Islands. Non-breeding short-tailed albatross concentrate foraging in oceanic areas characterized by gradients in topography and water column productivity. This study provides an understanding of the foraging ecology for a highly migratory, imperiled seabird, and confirms the importance of shelf break and slope regions as hot spots for a variety of top marine predators in the North Pacific.

  12. Tarski's plank problem revisited

    Microsoft Academic Search

    Karoly Bezdek

    2009-01-01

    In the 1930's, Tarski introduced his plank problem at a time when the field Discrete Geometry was about to born. It is quite remarkable that Tarski's question and its variants continue to generate interest in the geometric and analytic aspects of coverings by planks in the present time as well. The paper is a survey type with a list of

  13. The Toolbox Revisited: Paths to Degree Completion From High School Through College

    ERIC Educational Resources Information Center

    Adelman, Clifford

    2006-01-01

    The Toolbox Revisited is a data essay that follows a nationally representative cohort of students from high school into postsecondary education, and asks what aspects of their formal schooling contribute to completing a bachelor's degree by their mid-20s. The universe of students is confined to those who attended a four-year college at any time,

  14. THE BOY WHO CRIED WOLF REVISITED: THE IMPACT OF FALSE ALARM INTOLERANCE ON

    E-print Network

    Stevenson, Paul

    THE BOY WHO CRIED WOLF REVISITED: THE IMPACT OF FALSE ALARM INTOLERANCE ON COST-LOSS SCENARIOS M's fable about the "The Boy who Cried Wolf", a young shepherd boy guarding the village flock cries. This event is repeated two or three times before a wolf actually does show up on the hillside. The boy cries

  15. ccsd-00008676,version1-13Sep2005 Quadratic Quantum Hamiltonians revisited

    E-print Network

    Boyer, Edmond

    is a survey concerning exact useful formulas for time dependent Schrodinger equations with quadratic quadratic Schrodinger equation and Gaus- sian Coherent States. It is well known and clearccsd-00008676,version1-13Sep2005 Quadratic Quantum Hamiltonians revisited Monique Combescure IPNL

  16. EPR before EPR: A 1930 Einstein-Bohr thought Experiment Revisited

    ERIC Educational Resources Information Center

    Nikolic, Hrvoje

    2012-01-01

    In 1930, Einstein argued against the consistency of the time-energy uncertainty relation by discussing a thought experiment involving a measurement of the mass of the box which emitted a photon. Bohr seemingly prevailed over Einstein by arguing that Einstein's own general theory of relativity saves the consistency of quantum mechanics. We revisit

  17. The Hare and the Tortoise Revisited : The New Politics of Consumer and Environmental Regulation in Europe

    E-print Network

    Kammen, Daniel M.

    in Europe David Vogel A paper submitted to the British Journal of Political Science Revised August, 20021 The Hare and the Tortoise Revisited : The New Politics of Consumer and Environmental Regulation. At the same time, regulatory politics and policies continue to exhibit substantial cross-national variation

  18. The Native Bee Fauna of Carlinville, Illinois, Revisited After 75 Years: a Case for Persistence

    Microsoft Academic Search

    John C. Marlin; Wallace E. LaBerge

    2009-01-01

    As a follow-up to the observations of Charles Robertson from 1884 to 1916, we revisited the Carlinville, Illinois, area between 18 August 1970 and 13 September1972 to sample and identify bee species (Hymenoptera: Apoidea). We concentrated on collecting nonparasitic bees (and excluded Apis and Bombus) visiting 24 plant species that bloomed at various times of the year, and upon which

  19. REVISITING THE CLASSICS: CONSIDERING NONCONSUMPTIVE EFFECTS IN TEXTBOOK EXAMPLES OF PREDATORPREY INTERACTIONS

    Microsoft Academic Search

    Barbara L. Peckarsky; Peter A. Abrams; Daniel I. Bolnick; Lawrence M. Dill; Jonathan H. Grabowski; Barney Luttbeg; John L. Orrock; Scott D. Peacor; Evan L. Preisser; Oswald J. Schmitz; Geoffrey C. Trussell

    2008-01-01

    Predator effects on prey dynamics are conventionally studied by measuring changes in prey abundance attributed to consumption by predators. We revisit four classic examples of predator-prey systems often cited in textbooks and incorporate subsequent studies of nonconsumptive effects of predators (NCE), defined as changes in prey traits (e.g., behavior, growth, development) measured on an ecological time scale. Our review revealed

  20. Effect of short-term unloading on T2 relaxation time in the lumbar intervertebral discinvivo magnetic resonance imaging study at 3.0 tesla

    PubMed Central

    Stelzeneder, David; Kovcs, Balzs K.; Goed, Sabine; Welsch, Goetz H.; Hirschfeld, Clemens; Paternostro-Sluga, Tatjana; Friedrich, Klaus M.; Mamisch, Tallal C.; Trattnig, Siegfried

    2012-01-01

    Background context Diurnal changes in T2 values, indicative for changes in water content, have been reported in the lumbar intervertebral discs. However, data concerning short-term T2 changes are missing. Purpose The purpose of this study was to investigate the short-term effects of unloading on T2 values in lumbar intervertebral discs invivo. Study design Experimental study with repeated measurements of lumbar discs T2 relaxation time during a period of 38 minutes of supine posture. Patient sample Forty-one patients with acute or chronic low back pain (visual analog scale ?3). Outcome measures T2 relaxation time in the intervertebral disc, lumbar lordosis angle, and intervertebral disc height. Methods Forty-one patients (mean age, 41.6 years) were investigated in the supine position using a 3-tesla magnetic resonance system. Sagittal T2 mapping was performed immediately after unloading and after a mean delay of 38 minutes. No patient movement was allowed between the measurements. One region of interest (ROI) was manually placed in both the anterior and the posterior annulus fibrosus (AF) and three ROIs in the nucleus pulposus (NP). Results There was a statistically significant decrease in the anterior NP (?2.7 ms; p<.05) and an increase in T2 values in the posterior AF (+3.5 ms; p<.001). Discs with initially low T2 values in the NP showed minor increase in the posterior AF (+1.6 ms; p<.05), whereas a major increase in the posterior AF was found in discs with initially high T2 values in the NP (+6.8 ms; p=.001). Patients examined in the morning showed no differences, but those investigated in the afternoon showed a decrease in the anterior NP (?5.3 ms; p<.05) and an increase in the posterior AF (+7.8 ms; p=.002). No significant differences were observed in other regions. Correlation analysis showed moderate correlations between the time of investigation and T2 changes in the posterior AF (r=0.46; p=.002). Conclusions A shift of water from the anterior to the posterior disc regions seems to occur after unloading the lumbar spine in the supine position. The clinical relevance of these changes needs to be investigated. PMID:22469305

  1. Short-term foraging costs and long-term fueling rates in central-place foraging swans revealed by giving-up exploitation times.

    PubMed

    van Gils, J A; Tijsen, W

    2007-05-01

    Foragers tend to exploit patches to a lesser extent farther away from their central place. This has been interpreted as a response to increased risk of predation or increased metabolic costs of prey delivery. Here we show that migratory Bewick's swans (Cygnus columbianus bewickii), though not incurring greater predation risks farther out or delivering food to a central place, also feed for shorter periods at patches farther away from their roost. Predictions from an energy budget model suggest that increasing metabolic travel costs per se are responsible. Establishing the relation between intake rate and exploitation time enabled us to express giving-up exploitation times as quitting harvest rates (QHRs). This revealed that net QHRs were not different from observed long-term net intake rates, a sign that the birds were maximizing their long-term net intake rate. This study is unique because giving-up decisions were measured at the individual level, metabolic and predation costs were assessed simultaneously, the relation with harvest rate was made explicit, and finally, short-term giving-up decisions were related to long-term net intake rates. We discuss and conceptualize the implications of metabolic traveling costs for carrying-capacity predictions by bridging the gap between optimal-foraging theory and optimal-migration theory. PMID:17427132

  2. Treatment of a chocolate industry wastewater in a pilot-scale low-temperature UASB reactor operated at short hydraulic and sludge retention time.

    PubMed

    Esparza-Soto, M; Arzate-Archundia, O; Sols-Morelos, C; Fall, C

    2013-01-01

    The aim of this work was to evaluate the performance of a 244-L pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of chocolate-processing industry wastewater under low-temperature conditions (18 0.6 C) for approximately 250 d. The applied organic loading rate (OLR) was varied between 4 and 7 kg/m(3)/d by varying the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (6.4 0.3 h). The CODsol removal efficiency was low (59-78%). The measured biogas production increased from 240 54 to 431 61 L/d during the experiments. A significant linear correlation between the measured biogas production and removed OLR indicated that 81.69 L of biogas were produced per kg/m(3) of CODsol removed. Low average reactor volatile suspended solids (VSS) (2,700-4,800 mg/L) and high effluent VSS (177-313 mg/L) were derived in a short sludge retention time (SRT) (4.9 d). The calculated SRT was shorter than those reported in the literature, but did not affect the reactor's performance. Average sludge yield was 0.20 kg-VSS/kg-CODsol. The low-temperature anaerobic treatment was a good option for the pre-treatment of chocolate-processing industry wastewater. PMID:23508162

  3. Smith Theory Revisited William G. Dwyer

    E-print Network

    Wilkerson, Clarence

    Smith Theory Revisited William G. Dwyer Clarence W. Wilkerson* 1 Introduction In the late 1930's, P. A. Smith began the investigation. This thread has continued now for almost fifty years. Smith was successful in calculating the cohomology

  4. Faraday rotation revisited: The thermodynamic limit

    E-print Network

    Cornean, H D

    2008-01-01

    This paper is the second in a series revisiting the (effect of) Faraday rotation. We formulate and prove the thermodynamic limit for the transverse electric conductivity of Bloch electrons, as well as for the Verdet constant.

  5. Health risk of chrysotile revisited.

    PubMed

    Bernstein, David; Dunnigan, Jacques; Hesterberg, Thomas; Brown, Robert; Velasco, Juan Antonio Legaspi; Barrera, Ral; Hoskins, John; Gibbs, Allen

    2013-02-01

    This review provides a basis for substantiating both kinetically and pathologically the differences between chrysotile and amphibole asbestos. Chrysotile, which is rapidly attacked by the acid environment of the macrophage, falls apart in the lung into short fibers and particles, while the amphibole asbestos persist creating a response to the fibrous structure of this mineral. Inhalation toxicity studies of chrysotile at non-lung overload conditions demonstrate that the long (>20?m) fibers are rapidly cleared from the lung, are not translocated to the pleural cavity and do not initiate fibrogenic response. In contrast, long amphibole asbestos fibers persist, are quickly (within 7?d) translocated to the pleural cavity and result in interstitial fibrosis and pleural inflammation. Quantitative reviews of epidemiological studies of mineral fibers have determined the potency of chrysotile and amphibole asbestos for causing lung cancer and mesothelioma in relation to fiber type and have also differentiated between these two minerals. These studies have been reviewed in light of the frequent use of amphibole asbestos. As with other respirable particulates, there is evidence that heavy and prolonged exposure to chrysotile can produce lung cancer. The importance of the present and other similar reviews is that the studies they report show that low exposures to chrysotile do not present a detectable risk to health. Since total dose over time decides the likelihood of disease occurrence and progression, they also suggest that the risk of an adverse outcome may be low with even high exposures experienced over a short duration. PMID:23346982

  6. Health risk of chrysotile revisited

    PubMed Central

    Dunnigan, Jacques; Hesterberg, Thomas; Brown, Robert; Velasco, Juan Antonio Legaspi; Barrera, Ral; Hoskins, John; Gibbs, Allen

    2013-01-01

    This review provides a basis for substantiating both kinetically and pathologically the differences between chrysotile and amphibole asbestos. Chrysotile, which is rapidly attacked by the acid environment of the macrophage, falls apart in the lung into short fibers and particles, while the amphibole asbestos persist creating a response to the fibrous structure of this mineral. Inhalation toxicity studies of chrysotile at non-lung overload conditions demonstrate that the long (>20?m) fibers are rapidly cleared from the lung, are not translocated to the pleural cavity and do not initiate fibrogenic response. In contrast, long amphibole asbestos fibers persist, are quickly (within 7?d) translocated to the pleural cavity and result in interstitial fibrosis and pleural inflammation. Quantitative reviews of epidemiological studies of mineral fibers have determined the potency of chrysotile and amphibole asbestos for causing lung cancer and mesothelioma in relation to fiber type and have also differentiated between these two minerals. These studies have been reviewed in light of the frequent use of amphibole asbestos. As with other respirable particulates, there is evidence that heavy and prolonged exposure to chrysotile can produce lung cancer. The importance of the present and other similar reviews is that the studies they report show that low exposures to chrysotile do not present a detectable risk to health. Since total dose over time decides the likelihood of disease occurrence and progression, they also suggest that the risk of an adverse outcome may be low with even high exposures experienced over a short duration. PMID:23346982

  7. Transfer time and source tracing in the soil - water- -plant system deciphered by the U-and Th-series short-lived nuclides

    NASA Astrophysics Data System (ADS)

    Rihs, S.; Pierret, M.; Chabaux, F.

    2011-12-01

    Because soils form at the critical interface between the lithosphere and the atmosphere, characterization of the dynamics occurring through this compartment represents an important goal for several scientific fields and/or human activities. However, this issue remains a challenge because soils are complex systems, where a continuous evolution of minerals and organic soil constituents occurs in response to interactions with waters and vegetation. This study aims to investigate the relevance of short-lived nuclides of U- and Th-series to quantify the transfer times and scheme of radionuclides through a soil - water - plant ecosystem. Activities of (226Ra), (228Ra) and (228Th), as well as the long-lived (232Th), were measured by TIMS and gamma-spectrometry in the major compartments of a forested soil section, i.e.: solid soil fractions (exchangeable fraction, secondary phases and inherited primary minerals), waters (seepage soil waters and a spring further down the watershed) and vegetation (fine and coarse roots of beech trees, young and mature leaves). The matching of these nuclides half-live to bio-geochemical processes time-scale and the relatively good chemical analogy of radium with calcium make these isotopes especially suitable to investigate either time or mechanism of transfers within a soil-water-plant system. Indeed, the (228Ra/226Ra) isotopic ratios strongly differ in the range of samples, allowing quantifying the source and duration transfers. Analyses of the various solid soil fractions demonstrate a full redistribution of Ra isotopes between the inherited minerals and secondary soil phases. However, the transfer of these isotopes to the seepage water or to the tree roots does not follow a simple and obvious scheme. Both primary and secondary phases show to contribute to the dissolved radium. However, depending on the season, the tree leaves degradation also produces up to 70% of dissolved radium. Immobilization of a large part of this radium occurs within the first 70cm of the soil layer, either by plant uptake, or adsorption/ precipitation in particular soil layers. Consistently, the Ra isotope ratio in the spring water is similar to the inherited primary soil fraction, suggesting a "deep" (i.e. below the shallow 70cm of soil layer) origin of the exported dissolved radium and the short-scale effect of vegetation cycling onto radium transfer. The radium isotopic ratio in the trees roots does not match the soil exchangeable fraction, nor the seepage waters, but rather the bulk soil, suggesting a large and mixed pool of radium for roots uptake. Decay of 228Ra within the various parts of the trees allows calculating a vegetation cycling duration of about 10 years for this nuclide. Finally an unexpected large amount of unsupported 228Th in the tree leaves can only be explained by a preferential migration of the 228Ac (228Th precursor). The very short life of this nuclide allows therefore assessing that such transport from roots and deposition within stem and leaves take place within 30 hours at the most.

  8. Loco-regional therapy in patients with Milan Criteria-compliant hepatocellular carcinoma and short waitlist time to transplant: an outcome analysis

    PubMed Central

    Sourianarayanane, Achuthan; El-Gazzaz, Galal; Sanabria, Juan R; Menon, K V Narayanan; Quintini, Cristiano; Hashimoto, Koji; Kelly, Dympna; Eghtesad, Bijan; Miller, Charles; Fung, John; Aucejo, Federico

    2012-01-01

    Objectives Liver transplantation (LT) in Milan Criteria (MC) hepatocellular carcinoma (HCC) has excellent outcomes. Pre-transplant loco-regional therapy (LRT) has been used to downstage HCC to meet the MC. However, its benefit in patients with a brief waiting time to transplant remains unclear. This study evaluated outcomes in patients with short waitlist times to LT for MC-compliant HCC. Methods Patients undergoing LT for MC HCC at either of two transplant centres between 2002 and 2009 were retrospectively evaluated for outcome. Patients for whom post-transplant follow-up amounted to <12 months were excluded. Results A total of 225 patients were included, 93 (41.3%) of whom received neoadjuvant LRT. The median waiting time to transplant was 48 days. Mean post-transplant follow-up was 32.2 months. Overall and disease-free survival at 1 year, 3 years and 5 years were 93.1%, 82.4% and 72.6%, and 91.3%, 79.3% and 70.6%, respectively. There was no difference in overall (P = 0.94) and disease-free survival (P = 0.94) between groups who received and did not receive pre-LT LRT. There were also no disparities in survival or tumour recurrence among categories of patients (with single tumours measuring <3 cm, with single tumours measuring 35 cm, with multiple tumours). Conclusions Loco-regional therapy followed by rapid transplantation in MC HCC appears not to have an impact on post-transplant outcome. PMID:22487070

  9. Whole body sodium MRI at 3T using an asymmetric birdcage resonator and short echo time sequence: first images of a male volunteer.

    PubMed

    Wetterling, Friedrich; Corteville, Dominique M; Kalayciyan, Raffi; Rennings, Andreas; Konstandin, Simon; Nagel, Armin M; Stark, Helmut; Schad, Lothar R

    2012-07-21

    Sodium magnetic resonance imaging (Na MRI) is a non-invasive technique which allows spatial resolution of the tissue sodium concentration (TSC) in the human body. TSC measurements could potentially serve to monitor early treatment success of chemotherapy on patients who suffer from whole body metastases. Yet, the acquisition of whole body sodium (Na) images has been hampered so far by the lack of large resonators and the extremely low signal-to-noise ratio (SNR) achieved with existing resonator systems. In this study, a Na resonator was constructed for whole body Na MRI at 3T comprising of a 16-leg, asymmetrical birdcage structure with 34 cm height, 47.5 cm width and 50 cm length. The resonator was driven in quadrature mode and could be used either as a transceiver resonator or, since active decoupling was included, as a transmit-only resonator in conjunction with a receive-only (RO) surface resonator. The relative B?-field profile was simulated and measured on phantoms, and 3D whole body Na MRI data of a healthy male volunteer were acquired in five segments with a nominal isotropic resolution of (6 6 6) mm and a 10 min acquisition time per scan. The measured SNR values in the Na-MR images varied from 9 2 in calf muscle, 15 2 in brain tissue, 23 2 in the prostate and up to 42 5 in the vertebral discs. Arms, legs, knees and hands could also be resolved with applied resonator and short time-to-echo (TE) (0.5 ms) radial sequence. Up to fivefold SNR improvement was achieved through combining the birdcage with local RO surface coil. In conclusion, Na MRI of the entire human body provides sub-cm spatial resolution, which allows resolution of all major human body parts with a scan time of less than 60 min. PMID:22722731

  10. Whole body sodium MRI at 3T using an asymmetric birdcage resonator and short echo time sequence: first images of a male volunteer

    NASA Astrophysics Data System (ADS)

    Wetterling, Friedrich; Corteville, Dominique M.; Kalayciyan, Raffi; Rennings, Andreas; Konstandin, Simon; Nagel, Armin M.; Stark, Helmut; Schad, Lothar R.

    2012-07-01

    Sodium magnetic resonance imaging (23Na MRI) is a non-invasive technique which allows spatial resolution of the tissue sodium concentration (TSC) in the human body. TSC measurements could potentially serve to monitor early treatment success of chemotherapy on patients who suffer from whole body metastases. Yet, the acquisition of whole body sodium (23Na) images has been hampered so far by the lack of large resonators and the extremely low signal-to-noise ratio (SNR) achieved with existing resonator systems. In this study, a 23Na resonator was constructed for whole body 23Na MRI at 3T comprising of a 16-leg, asymmetrical birdcage structure with 34 cm height, 47.5 cm width and 50 cm length. The resonator was driven in quadrature mode and could be used either as a transceiver resonator or, since active decoupling was included, as a transmit-only resonator in conjunction with a receive-only (RO) surface resonator. The relative B1-field profile was simulated and measured on phantoms, and 3D whole body 23Na MRI data of a healthy male volunteer were acquired in five segments with a nominal isotropic resolution of (6 6 6) mm3 and a 10 min acquisition time per scan. The measured SNR values in the 23Na-MR images varied from 9 2 in calf muscle, 15 2 in brain tissue, 23 2 in the prostate and up to 42 5 in the vertebral discs. Arms, legs, knees and hands could also be resolved with applied resonator and short time-to-echo (TE) (0.5 ms) radial sequence. Up to fivefold SNR improvement was achieved through combining the birdcage with local RO surface coil. In conclusion, 23Na MRI of the entire human body provides sub-cm spatial resolution, which allows resolution of all major human body parts with a scan time of less than 60 min.

  11. Adaptive Individual Differences Revisited

    Microsoft Academic Search

    David M. Buss

    1999-01-01

    Humans possess a complex array of evolved psychological mechanisms, only a subset of which is activated at any particular time. Attempts to reduce human sexual strategies to a single, rigid, invariant strategy, and to label departures from a single strategy as maladjusted, fail to accord with a large body of empirical evidence. Personality psychology cannot afford to ignore the rich

  12. The plasmapause revisited

    NASA Technical Reports Server (NTRS)

    Maynard, N. C.; Gebowsky, J. M.

    1976-01-01

    Saturation of the dc double probe instrument on Explorer 45 was used to identify the plasmapause. A data base was developed to statistically study the average position of the plasmapause over 14.5 hours of magnetic local time under differing magnetic conditions. The afternoon-evening bulge in the L coordinate of the plasmapause versus local time was found centered between 20 and 21 hours MLT during magnetically quiet periods and shifted toward dusk as activity increased, but always post dusk. During quiet periods a bulge in the L coordinate near noon was also seen, which disappeared as activity increased. The average local time distribution plasmapause position during high magnetic activity was irregular in the afternoon region where large scale convection models predict the creation of plasmatails or detached plasma regions from increases in the solar wind induced convection. The results suggest that solar wind induced convection is partially shielded from the dayside. As the intensity of the convection is increased, it more effectively penetrates the dayside, which shifts the post dusk bulge nearer to dusk and eliminates the quiet-time bulge near noon.

  13. Ultrasonic Interferometers Revisited

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2007-01-01

    I have been tinkering with ultrasonic transducers once more. In earlier notes I reported on optics-like experiments performed with ultrasonics, described a number of ultrasonic interferometers, and showed how ultrasonic transducers can be used for Fourier analysis. This time I became interested in trying the technique of using two detectors in

  14. Asymptotic phase revisited

    Microsoft Academic Search

    Carmen Chicone; Weishi Liu

    2004-01-01

    We discuss the classical problem on asymptotic phase of periodic orbits of planar systems. The existence of asymptotic phase for non-hyperbolic periodic orbits is completely determined with hypotheses on the derivatives of a Poincar map and a return-time map. Smoothness of the vector field turns out to be crucial for existence of asymptotic phase. For hyperbolic periodic orbits, a new

  15. Short Time Impulse Response Function (STIRF) for automatic evaluation of the variation of the dynamic parameters of reinforced concrete framed structures during strong earthquakes.

    NASA Astrophysics Data System (ADS)

    Carlo Ponzo, Felice; Ditommaso, Rocco

    2015-04-01

    This study presents an innovative strategy for automatic evaluation of the variable fundamental frequency and related damping factor of nonlinear structures during strong motion phases. Most of methods for damage detection are based on the assessment of the variations of the dynamic parameters characterizing the monitored structure. A crucial aspect of these methods is the automatic and accurate estimation of both structural eigen-frequencies and related damping factors also during the nonlinear behaviour. A new method, named STIRF (Short-Time Impulse Response Function - STIRF), based on the nonlinear interferometric analysis combined with the Fourier Transform (FT) here is proposed in order to allow scientists and engineers to characterize frequencies and damping variations of a monitored structure. The STIRF approach helps to overcome some limitation derived from the use of techniques based on simple Fourier Transform. These latter techniques provide good results when the response of the monitored system is stationary, but fails when the system exhibits a non-stationary, time-varying behaviour: even non-stationary input, soil-foundation and/or adjacent structures interaction phenomena can show the inadequacy of classic techniques to analysing the nonlinear and/or non-stationary behaviour of structures. In fact, using this kind of approach it is possible to improve some of the existing methods for the automatic damage detection providing stable results also during the strong motion phase. Results are consistent with those expected if compared with other techniques. The main advantage derived from the use of the proposed approach (STIRF) for Structural Health Monitoring is based on the simplicity of the interpretation of the nonlinear variations of the fundamental frequency and the related equivalent viscous damping factor. The proposed methodology has been tested on both numerical and experimental models also using data retrieved from shaking table tests. Based on the results provided in this study, the methodology seems to be able to evaluate fast variations (over time) of dynamic parameters of a generic reinforced concrete framed structure. Further analyses are necessary to better calibrate the length of the moving time-window (in order to minimize the spurious frequency within each Interferometric Response Function evaluated on both weak and strong motion phases) and to verify the possibility to use the STIRF to analyse the nonlinear behaviour of general systems. Acknowledgements This study was partially funded by the Italian Civil Protection Department within the project DPC-RELUIS 2014 - RS4 ''Seismic observatory of structures and health monitoring''. References R. Ditommaso, F.C. Ponzo (2015). Automatic evaluation of the fundamental frequency variations and related damping factor of reinforced concrete framed structures using the Short Time Impulse Response Function (STIRF). Engineering Structures, 82 (2015), 104-112. http://dx.doi.org/10.1016/j.engstruct.2014.10.023.

  16. Reframing Academic Literacy: Re-Examining a Short-Course for "Disadvantaged" Tertiary Students

    ERIC Educational Resources Information Center

    Henderson, Robyn; Hirst, Elizabeth

    2007-01-01

    This paper revisits a successful short-course in academic literacy that was conducted for 50 "disadvantaged" students enrolled in the first year of an education degree at an Australian regional university (see Hirst, Henderson, Allan, Bode & Kocatepe, 2004). Based on a sociocultural approach to learning and drawing on a conceptualisation of

  17. GENTLEMANLY CAPITALISM REVISITED: A CASE STUDY OF THE UNDERPRICING OF INITIAL PUBLIC OFFERINGS ON THE LONDON STOCK EXCHANGE 1946-86

    Microsoft Academic Search

    David Chambers

    2006-01-01

    Allegations of British capital market failure are numerous, range from claims of domestic investor bias before 1914 to charges of short-termism against institutional investors towards the end of the last century, and are frequently contentious. This paper revisits this literature by pointing to the post-1945 market for initial public offerings (IPO) as a clear instance of capital market failure. Despite

  18. Carbon Tariffs Revisited The Harvard Project on Climate Agreements

    E-print Network

    Liu, X. Shirley

    Carbon Tariffs Revisited The Harvard Project on Climate Agreements March 2014 Discussion Paper 14;#12;Carbon Tariffs Revisited Christoph Bhringer University of Oldenburg Germany Andr Mller ECOPLAN, and Jan Schneider. "Carbon Tariffs Revisited." Discussion Paper 2014-64. Cambridge, Mass.: Harvard Project

  19. ...... Frechet Distance Revisited and Extended Sariel Har-Peled1

    E-print Network

    Har-Peled, Sariel

    . ...... Fr´echet Distance Revisited and Extended Sariel Har-Peled1 Benjamin Raichel1 1UIUC, Illinois, USA June 15, 2011 Har-Peled and Raichel (UIUC) Fr´echet Distance Revisited and Extended June 15 recognition, etc. Har-Peled and Raichel (UIUC) Fr´echet Distance Revisited and Extended June 15, 2011 2 / 26

  20. The relativistic glider revisited

    E-print Network

    L. Bergamin; P. Delva; A. Hees

    2009-09-25

    In this paper we analyze some aspects of the "relativistic glider" proposed by Gu\\'eron and Mosna more in detail. In particular an explicit weak gravity and low velocity expansion is presented, the influence of different initial conditions are studied and the behavior of the glider over a longer integration time is presented. Our results confirm that the system can be used as a glider, but is not able to stop or even revert the fall of an object.

  1. Short-time scale variation of phytoplankton succession in Lisbon bay (Portugal) as revealed by microscopy cell counts and HPLC pigment analysis

    NASA Astrophysics Data System (ADS)

    Silva, A.; Mendes, C. R.; Palma, S.; Brotas, V.

    2008-08-01

    The phytoplankton distribution and composition in Lisbon bay was studied, at a short time scale based on a weekly sampling, during one year (April 2004 - May 2005), using microscopic examination and pigment analysis with high-performance liquid chromatography (HPLC). This work is a contribution to the knowledge on species succession and ecology of coastal communities. The frequency of the sampling permitted monitoring peak blooming and decaying, a process which frequently occurred within 1 -2 weeks. Cell counts determined that the classes Dinophyceae, Bacillariophyceae and Prymnesiophyceae dominated the assemblages. Maxima abundances and diversity of phytoplankton were observed from spring to autumn. HPLC analysis reflected the major seasonal variations observed by the cell counts and in addition detected the presence of four small sized phytoplankton classes that were not identified by microscopy. Phytoplankton counts were essential to identify the main contributing species to total chlorophyll a. Fucoxantin, peridinin and 19'-hexanoyloxyfucoxanthin appeared as good indicators for diatoms, dinoflagellates and coccolithophores, respectively, with synchronized seasonal variations and significant positive correlations.

  2. Short-time exposure to mono-n-butyl phthalate (MBP)-induced oxidative stress associated with DNA damage and the atrophy of the testis in pubertal rats.

    PubMed

    Shono, Takeshi; Taguchi, Tomoaki

    2014-02-01

    Phthalates are widely used as plasticizer in various consumer domestic products and are known to disturb the male reproductive function in rodents. This study investigated the involvement of oxidative stress and the atrophy of the testes in pubertal rats exposed to mono-n-butyl phthalate (MBP). Four-week-old pubertal male rats were separated into three groups. In group I, 21 rats were fed rat chow containing 2 % MBP for 3 days. In group II, 21 rats were fed rat chow containing 2 % MBP for 3 days and antioxidant vitamins C (250 mg/kg/day) and E (50 mg/kg/day) were injected daily. In group III, 21 rats were fed standard rat chow and used as controls. After 3 days, each testis was weighed and the germ cell development was evaluated using the Johnsen score. The urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were measured as a biological marker of oxidative DNA damage. The mean testis weight was significantly lower for group I than groups II or III (p?Short-time exposure to MBP may therefore induce oxidative DNA damage in rat testes, while antioxidant vitamins administered during exposure may protect against this stress. PMID:24310901

  3. The effect of short-time microwave exposures on Escherichia coli O157:H7 inoculated onto chicken meat portions and whole chickens.

    PubMed

    Apostolou, I; Papadopoulou, C; Levidiotou, S; Ioannides, K

    2005-05-01

    Small portions of fresh chicken breasts weighting 20 g each and fresh whole chickens, weighting on average 1310 g each, were inoculated with Escherichia coli O157:H7 (10(5)-10(6) cfu/g) and cooked, using two different domestic microwave ovens at full power. The chicken portions were heated for 5, 10, 15, 20, 25, 30, and 35 s and the whole chickens for 22 min. Following exposures, viable counts and temperature measurements were performed. Although the chicken breast portions looked well-cooked after 30 s of MW heating at a mean end-point surface temperature of 69.8 degrees C, a mean concentration of 83 cfu/g E. coli O157:H7 cells was recovered. Elimination of E. coli O157:H7 cells occurred only after 35 s of MW exposure at 73.7 degrees C. When whole chickens were thoroughly cooked by MW heating, the final subsurface temperatures, measured in the thighs and wings, ranged from 60.2 degrees C to 92 degrees C and viable cells of E. coli O157:H7 were recovered from all samples of whole chicken. The results indicate that short time exposures of chicken portions to microwave heating do not eliminate E. coli O157:H7. PMID:15878411

  4. Statistical Time-resolved Spectroscopy: A Higher Fraction of Short-period Binaries for Metal-rich F-type Dwarfs in SDSS

    NASA Astrophysics Data System (ADS)

    Hettinger, T.; Badenes, C.; Strader, J.; Bickerton, S. J.; Beers, T. C.

    2015-06-01

    Stellar multiplicity lies at the heart of many problems in modern astrophysics, including the physics of star formation, the observational properties of unresolved stellar populations, and the rates of interacting binaries such as cataclysmic variables, X-ray binaries, and SNe Ia. However, little is known about the stellar multiplicity of field stars in the Milky Way (MW), in particular about the differences in the multiplicity characteristics between metal-rich disk stars and metal-poor halo stars. In this study we perform a statistical analysis of ?14,000 F-type dwarf stars in the MW through time-resolved spectroscopy with the sub-exposures archived in the Sloan Digital Sky Survey. We obtain absolute radial velocity (RV) measurements through template cross-correlation of individual sub-exposures with temporal baselines varying from minutes to years. These sparsely sampled RV curves are analyzed using Markov chain Monte Carlo techniques to constrain the very short-period binary fraction for field F-type stars in the MW. Metal-rich disk stars were found to be 30% more likely to have companions with periods shorter than 12 days than metal-poor halo stars.

  5. Statistical Time-Resolved Spectroscopy: A higher fraction of short-period binaries for metal-rich F-type dwarfs in SDSS

    E-print Network

    Hettinger, T; Strader, J; Bickerton, S J; Beers, T C

    2015-01-01

    Stellar multiplicity lies at the heart of many problems in modern astrophysics, including the physics of star formation, the observational properties of unresolved stellar populations, and the rates of interacting binaries such as cataclysmic variables, X-ray binaries, and Type Ia supernovae. However, little is known about the stellar multiplicity of field stars in the Milky Way, in particular about the differences in the multiplicity characteristics between metal-rich disk stars and metal-poor halo stars. In this study we perform a statistical analysis of ~15,000 F-type dwarf stars in the Milky Way through time-resolved spectroscopy with the sub-exposures archived in the Sloan Digital Sky Survey. We obtain absolute radial velocity measurements through template cross-correlation of individual sub-exposures with temporal baselines varying from minutes to years. These sparsely sampled radial velocity curves are analyzed using Markov chain Monte Carlo techniques to constrain the very short-period binary fraction...

  6. Strasbourg Observatory Archives Revisited

    NASA Astrophysics Data System (ADS)

    Heck, A.

    2002-12-01

    Official talks in France and Germany after World War I were generally of hatred and revenge. Strasbourg Observatory had just changed nationality (from Prussian to French) for the first time (this would happen again at the outbreak of WWII and after the conflict). Documents show that astronomers did not share the general attitude. For example the inventory book started in German was continued in French after 1918. It is moving to see those different handwritings in two different languages on the same pages -- making of that book a unique document in various respects, but also reminding us that the native language of the region was in fact Alsacian.

  7. Nursing knowledge, theory and method revisited.

    PubMed

    Booth, K; Kenrick, M; Woods, S

    1997-10-01

    With the approach of the 21st century, nursing is having to respond to diverse influences which are remoulding the professional landscape. Not least of these is the changing status of western economies which underpins a drive towards evidence-based practice and an increased emphasis on multidisciplinary approaches to health care delivery. Certainty in health care is now a thing of the past. Central to the way the nursing profession embraces the future is its underlying philosophy: that which articulates professional values and shapes practice, research, education and management. In a time of change it is therefore essential to revisit the philosophical framework which underpins nursing. The debate in nursing research and theory appears to have stressed the polarization of viewpoints. It may be the case that feminist writers, ethnographers, positivist researchers and nursing theorists, in defending their own points of view, diminish rather than enhance professional dialogue. This paper reviews the nature of this debate within nursing and considers the implications that a dichotomous position may have for knowledge, theory and research method within the current context of health care. It then suggests a philosophical framework which could be relevant and accessible across the whole spectrum of nursing activity. In so doing, the paper aims to contribute to the discussion around epistemology and method in a way which encompasses the diversity found within the broad church of nursing. PMID:9354995

  8. Revisiting the relaxation dynamics of isolated pyrrole

    SciTech Connect

    Montero, Ral; Ovejas, Virginia; Fernndez-Fernndez, Marta; Longarte, Asier, E-mail: asier.longarte@ehu.es [Departamento de Qumica Fsica, Universidad del Pas Vasco (UPV/EHU), Apart. 644, 48080 Bilbao (Spain); Peralta Conde, lvaro [Centro de Lseres Pulsados (CLPU), Edificio M3, Parque Cientfico, 37185 Villamayor (Spain)

    2014-07-07

    Herein, the interpretation of the femtosecond-scale temporal evolution of the pyrrole ion signal, after excitation in the 267217 nm interval, recently published by our group [R. Montero, A. Peralta Conde, V. Ovejas, M. Fernndez-Fernndez, F. Castao, J. R. Vzquez de Aldana, and A. Longarte, J. Chem. Phys.137, 064317 (2012)] is re-visited. The observation of a shift in the pyrrole{sup +} transient respect to zero delay reference, initially attributed to ultrafast dynamics on the ??{sup *} type state (3s a{sub 1} ? ? 1a{sub 2}), is demonstrated to be caused by the existence of pump + probe populated states, along the ionization process. The influence of these resonances in pump-prone ionization experiments, when multi-photon probes are used, and the significance of a proper zero-time reference, is discussed. The possibility of preparing the ??{sup *} state by direct excitation is investigated by collecting 1 + 1 photoelectron spectra, at excitation wavelengths ranging from 255 to 219 nm. No conclusive evidences of ionization through this state are found.

  9. Axion Cosmology Revisited

    E-print Network

    Olivier Wantz; E. P. S. Shellard

    2011-02-13

    The misalignment mechanism for axion production depends on the temperature-dependent axion mass. The latter has recently been determined within the interacting instanton liquid model (IILM), and provides for the first time a well-motivated axion mass for all temperatures. We reexamine the constraints placed on the axion parameter space in the light of this new mass function. We find an accurate and updated constraint $ f_a \\le 2.8(\\pm2)\\times 10^{11}\\units{GeV}$ or $m_a \\ge 21(\\pm2) \\units{\\mu eV}$ from the misalignment mechanism in the classic axion window (thermal scenario). However, this is superseded by axion string radiation which leads to $ f_a \\lesssim 3.2^{+4}_{-2} \\times 10^{10} \\units{GeV}$ or $m_a \\gtrsim 0.20 ^{+0.2}_{-0.1} \\units{meV}$. In this analysis, we take care to precisely compute the effective degrees of freedom and, to fill a gap in the literature, we present accurate fitting formulas. We solve the evolution equations exactly, and find that analytic results used to date generally underestimate the full numerical solution by a factor 2-3. In the inflationary scenario, axions induce isocurvature fluctuations and constrain the allowed inflationary scale $H_I$. Taking anharmonic effects into account, we show that these bounds are actually weaker than previously computed. Considering the fine-tuning issue of the misalignment angle in the whole of the anthropic window, we derive new bounds which open up the inflationary window near $\\theta_a \\to \\pi$. In particular, we find that inflationary dark matter axions can have masses as high as 0.01--1$\\units{meV}$, covering the whole thermal axion range, with values of $H_I$ up to $10^9$GeV. Quantum fluctuations during inflation exclude dominant dark matter axions with masses above $m_a\\lesssim 1$meV.

  10. Revisiting detrended fluctuation analysis

    PubMed Central

    Bryce, R. M.; Sprague, K. B.

    2012-01-01

    Half a century ago Hurst introduced Rescaled Range (R/S) Analysis to study fluctuations in time series. Thousands of works have investigated or applied the original methodology and similar techniques, with Detrended Fluctuation Analysis becoming preferred due to its purported ability to mitigate nonstationaries. We show Detrended Fluctuation Analysis introduces artifacts for nonlinear trends, in contrast to common expectation, and demonstrate that the empirically observed curvature induced is a serious finite-size effect which will always be present. Explicit detrending followed by measurement of the diffusional spread of a signals' associated random walk is preferable, a surprising conclusion given that Detrended Fluctuation Analysis was crafted specifically to replace this approach. The implications are simple yet sweeping: there is no compelling reason to apply Detrended Fluctuation Analysis as it 1) introduces uncontrolled bias; 2) is computationally more expensive than the unbiased estimator; and 3) cannot provide generic or useful protection against nonstationaries. PMID:22419991

  11. Revisiting detrended fluctuation analysis

    NASA Astrophysics Data System (ADS)

    Bryce, R. M.; Sprague, K. B.

    2012-03-01

    Half a century ago Hurst introduced Rescaled Range (R/S) Analysis to study fluctuations in time series. Thousands of works have investigated or applied the original methodology and similar techniques, with Detrended Fluctuation Analysis becoming preferred due to its purported ability to mitigate nonstationaries. We show Detrended Fluctuation Analysis introduces artifacts for nonlinear trends, in contrast to common expectation, and demonstrate that the empirically observed curvature induced is a serious finite-size effect which will always be present. Explicit detrending followed by measurement of the diffusional spread of a signals' associated random walk is preferable, a surprising conclusion given that Detrended Fluctuation Analysis was crafted specifically to replace this approach. The implications are simple yet sweeping: there is no compelling reason to apply Detrended Fluctuation Analysis as it 1) introduces uncontrolled bias; 2) is computationally more expensive than the unbiased estimator; and 3) cannot provide generic or useful protection against nonstationaries.

  12. Photon structure function revisited

    E-print Network

    Ch. Berger

    2014-12-22

    The flux of papers from electron positron colliders containing data on the photon structure function ended naturally around 2005. It is thus timely to review the theoretical basis and confront the predictions with a summary of the experimental results. The discussion will focus on the increase of the structure function with x (for x away from the boundaries) and its rise with log Q**2, both characteristics beeing dramatically different from hadronic structure functions. The agreement of the experimental observations with the theoretical calculations of the real and virtual photon structure is a striking success of QCD. It also allows a new determination of the QCD coupling constant which very well agrees with the value quoted in the literature.

  13. Polynomial Supertree Methods Revisited

    PubMed Central

    Brinkmeyer, Malte; Griebel, Thasso; Bcker, Sebastian

    2011-01-01

    Supertree methods allow to reconstruct large phylogenetic trees by combining smaller trees with overlapping leaf sets into one, more comprehensive supertree. The most commonly used supertree method, matrix representation with parsimony (MRP), produces accurate supertrees but is rather slow due to the underlying hard optimization problem. In this paper, we present an extensive simulation study comparing the performance of MRP and the polynomial supertree methods MinCut Supertree, Modified MinCut Supertree, Build-with-distances, PhySIC, PhySIC_IST, and super distance matrix. We consider both quality and resolution of the reconstructed supertrees. Our findings illustrate the tradeoff between accuracy and running time in supertree construction, as well as the pros and cons of voting- and veto-based supertree approaches. Based on our results, we make some general suggestions for supertree methods yet to come. PMID:22229028

  14. de Sitter supersymmetry revisited

    NASA Astrophysics Data System (ADS)

    Anous, Tarek; Freedman, Daniel Z.; Maloney, Alexander

    2014-07-01

    We present the basic = 1 superconformal field theories in four-dimensional de Sitter space-time, namely the non-abelian super Yang-Mills theory and the chiral multiplet theory with gauge interactions or cubic superpotential. These theories have eight supercharges and are invariant under the full SO(4, 2) group of conformal symmetries, which includes the de Sitter isometry group SO(4, 1) as a subgroup. The theories are ghost-free and the anti-commutator ? ? { Q ? , Q ? } is positive. SUSY Ward identities uniquely select the Bunch-Davies vacuum state. This vacuum state is invariant under superconformal transformations, despite the fact that de Sitter space has non-zero Hawking temperature. The = 1 theories are classically invariant under the SU(2 , 2|1) superconformal group, but this symmetry is broken by radiative corrections. However, no such difficulty is expected in the = 4 theory, which is presented in appendix B.

  15. The Equivalence Principle Revisited

    E-print Network

    R. Aldrovandi; P. B. Barros; J. G. Pereira

    2002-12-07

    A precise formulation of the strong Equivalence Principle is essential to the understanding of the relationship between gravitation and quantum mechanics. The relevant aspects are reviewed in a context including General Relativity, but allowing for the presence of torsion. For the sake of brevity, a concise statement is proposed for the Principle: "An ideal observer immersed in a gravitational field can choose a reference frame in which gravitation goes unnoticed". This statement is given a clear mathematical meaning through an accurate discussion of its terms. It holds for ideal observers (time-like smooth non-intersecting curves), but not for real, spatially extended observers. Analogous results hold for gauge fields. The difference between gravitation and the other fundamental interactions comes from their distinct roles in the equation of force.

  16. ``Frames of Reference'' revisited

    NASA Astrophysics Data System (ADS)

    Steyn-Ross, Alistair; Ivey, Donald G.

    1992-12-01

    The PSSC teaching film, ``Frames of Reference,'' was made in 1960, and was one of the first audio-visual attempts at showing how your physical ``point of view,'' or frame of reference, necessarily alters both your perceptions and your observations of motion. The gentle humor and original demonstrations made a lasting impact on many audiences, and with its recent re-release as part of the AAPT Cinema Classics videodisc it is timely that we should review both the message and the methods of the film. An annotated script and photographs from the film are presented, followed by extension material on rotating frames which teachers may find appropriate for use in their classrooms: constructions, demonstrations, an example, and theory.

  17. Nanoelectrospray peptide mapping revisited

    NASA Astrophysics Data System (ADS)

    Lu, Aiping; Waanders, Leonie F.; Almeida, Reinaldo; Li, Guoqing; Allen, Mark; Cox, Jrgen; Olsen, Jesper V.; Bonaldi, Tiziana; Mann, Matthias

    2007-12-01

    Mass spectrometric (MS) determination of the primary structure of proteins, including post-translational modifications, remains a challenging task. Proteins are usually digested to tryptic peptides that are measured either by MALDI peptide mapping or by liquid chromatography online coupled to tandem MS (LC-MS/MS). Here we instead analyze peptides by a chip implementation of nanoelectrospray (TriVersa Nanomate, Advion Biosciences), coupled to a linear ion-trap-orbitrap hybrid instrument (LTQ-Orbitrap, Thermo Fisher). The C-trap connecting the linear ion-trap and orbitrap is filled repeatedly in different m/z ranges with up to a million charges. Each range is analyzed in the orbitrap repeatedly and separately, creating a survey spectrum composed of hundreds of single spectra. The composite spectrum is inherently normalized for different m/z ranges due to their different fill times and retains information on the variability of mass measurement and intensity. Nanoelectrospray offers analysis times of more than 30 min/[mu]l of peptide mixture, sufficient for in-depth peptide characterization by high resolution C-trap fragmentation in addition to high sensitivity ion-trap fragment analysis. We obtain over 6000-fold dynamic range and subfemtomole sensitivity. Automated analysis of digested BSA resulted in sequence coverage above 80% in low femtomole amounts. We also demonstrate identification of seven modified peptides for a purified histone H3 sample. Static spray allows relative quantitation of the same peptide with different modifications. Chip-based nanoelectrospray on an orbitrap instrument thus allows very high confidence protein identification and modification mapping and is an alternative to MALDI peptide mapping and LC-MS/MS.

  18. Forensic seismology revisited

    NASA Astrophysics Data System (ADS)

    Douglas, A.

    2007-01-01

    The first technical discussions, held in 1958, on methods of verifying compliance with a treaty banning nuclear explosions, concluded that a monitoring system could be set up to detect and identify such explosions anywhere except underground: the difficulty with underground explosions was that there would be some earthquakes that could not be distinguished from an explosion. The development of adequate ways of discriminating between earthquakes and underground explosions proved to be difficult so that only in 1996 was a Comprehensive Nuclear Test Ban Treaty (CTBT) finally negotiated. Some of the important improvements in the detection and identification of underground teststhat is in forensic seismologyhave been made by the UK through a research group at the Atomic Weapons Establishment (AWE). The paper describes some of the advances made in identification since 1958, particularly by the AWE Group, and the main features of the International Monitoring System (IMS), being set up to verify the Test Ban. Once the Treaty enters into force, then should a suspicious disturbance be detected the State under suspicion of testing will have to demonstrate that the disturbance was not a test. If this cannot be done satisfactorily the Treaty has provisions for on-site inspections (OSIs): for a suspicious seismic disturbance for example, an international team of inspectors will search the area around the estimated epicentre of the disturbance for evidence that a nuclear test really took place. Early observations made at epicentral distances out to 2,000 km from the Nevada Test Site showed that there is little to distinguish explosion seismograms from those of nearby earthquakes: for both source types the short-period (SP: 1 Hz) seismograms are complex showing multiple arrivals. At long range, say 3,000 10,000 km, loosely called teleseismic distances, the AWE Group noted that SP P wavesthe most widely and well-recorded waves from underground explosionswere in contrast simple, comprising one or two cycles of large amplitude followed by a low-amplitude coda. Earthquake signals on the other hand were often complex with numerous arrivals of similar amplitude spread over 35 s or more. It therefore appeared that earthquakes could be recognised on complexity. Later however, complex explosion signals were observed which reduced the apparent effectiveness of complexity as a criterion for identifying earthquakes. Nevertheless, the AWE Group concluded that for many paths to teleseismic distances, Earth is transparent for P signals and this provides a window through which source differences will be most clearly seen. Much of the research by the Group has focused on understanding the influence of source type on P seismograms recorded at teleseismic distances. Consequently the paper concentrates on teleseismic methods of distinguishing between explosions and earthquakes. One of the most robust criteria for discriminating between earthquakes and explosions is the m b : M s criterion which compares the amplitudes of the SP P waves as measured by the body-wave magnitude m b, and the long-period (LP: 0.05 Hz) Rayleigh-wave amplitude as measured by the surface-wave magnitude M s; the P and Rayleigh waves being the main wave types used in forensic seismology. For a given M s, the m b for explosions is larger than for most earthquakes. The criterion is difficult to apply however, at low magnitude (say m b < 4.5) and there are exceptionsearthquakes that look like explosions. A difficulty with identification criteria developed in the early days of forensic seismology was that they were in the main empiricalit was not known why they appeared to work and if there were test sites or earthquakes where they would fail. Consequently the AWE Group in cooperation with the University of Cambridge used seismogram modelling to try and understand what controls complexity of SP P seismograms, and to put the m b : M s criterion on a theoretical basis. The results of this work show that the m b : M s criterion is robust because several factors con

  19. Orthopaedic service lines-revisited.

    PubMed

    Patterson, Cheryl

    2008-01-01

    This article revisits the application of orthopaedic service lines from early introduction and growth of this organizational approach in the 1980s, through the 1990s, and into the current decade. The author has experienced and worked in various service-line structures through these three decades, as well as the preservice-line era of 1970s orthopaedics. Past lessons learned during earlier phases and then current trends and analysis by industry experts are summarized briefly, with indication given of the future for service lines. Variation versus consistency of certain elements in service-line definitions and in operational models is discussed. Main components of service-line structures and typical processes are described briefly, along with a more detailed section on the service-line director/manager role. Current knowledge contained here will help guide the reader to more "out-of-the-box" thinking toward comprehensive orthopaedic centers of excellence. PMID:18300683

  20. Secret Public Key Protocols Revisited

    NASA Astrophysics Data System (ADS)

    Lim, Hoon Wei; Paterson, Kenneth G.

    Password-based protocols are important and popular means of providing human-to-machine authentication. The concept of secret public keys was proposed more than a decade ago as a means of securing password-based authentication protocols against off-line password guessing attacks, but was later found vulnerable to various attacks. In this paper, we revisit the concept and introduce the notion of identity-based secret public keys. Our new identity-based approach allows secret public keys to be constructed in a very natural way using arbitrary random strings, eliminating the structure found in, for example, RSA or ElGamal keys. We examine identity-based secret public key protocols and give informal security analyses, indicating that they are secure against off-line password guessing and other attacks.

  1. Effect of Commercial-Scale High-Temperature, Short-Time Pasteurization on the Viability of Mycobacterium paratuberculosis in Naturally Infected Cows' Milk

    PubMed Central

    Grant, Irene R.; Hitchings, Edward I.; McCartney, Alan; Ferguson, Fiona; Rowe, Michael T.

    2002-01-01

    Raw cows' milk naturally infected with Mycobacterium paratuberculosis was pasteurized with an APV HXP commercial-scale pasteurizer (capacity 2,000 liters/h) on 12 separate occasions. On each processing occasion, milk was subjected to four different pasteurization treatments, viz., 73C for 15 s or 25 s with and without prior homogenization (2,500 lb/in2 in two stages), in an APV Manton Gaulin KF6 homogenizer. Raw and pasteurized milk samples were tested for M. paratuberculosis by immunomagnetic separation (IMS)-PCR (to detect the presence of bacteria) and culture after decontamination with 0.75% (wt/vol) cetylpyridinium chloride for 5 h (to confirm bacterial viability). On 10 of the 12 processing occasions, M. paratuberculosis was detectable by IMS-PCR, culture, or both in either raw or pasteurized milk. Overall, viable M. paratuberculosis was cultured from 4 (6.7%) of 60 raw and 10 (6.9%) of 144 pasteurized milk samples. On one processing day, in particular, M. paratuberculosis appeared to have been present in greater abundance in the source raw milk (evidenced by more culture positives and stronger PCR signals), and on this occasion, surviving M. paratuberculosis bacteria were isolated from milk processed by all four heat treatments, i.e., 73C for 15 and 25 s with and without prior homogenization. On one other occasion, surviving M. paratuberculosis bacteria were isolated from an unhomogenized milk sample that had been heat treated at 73C for 25 s. Results suggested that homogenization increases the lethality of subsequent heat treatment to some extent with respect to M. paratuberculosis, but the extended 25-s holding time at 73C was found to be no more effective at killing M. paratuberculosis than the standard 15-s holding time. This study provides clear evidence that M. paratuberculosis bacteria in naturally infected milk are capable of surviving commercial high-temperature, short-time pasteurization if they are present in raw milk in sufficient numbers. PMID:11823197

  2. Effect of commercial-scale high-temperature, short-time pasteurization on the viability of Mycobacterium paratuberculosis in naturally infected cows' milk.

    PubMed

    Grant, Irene R; Hitchings, Edward I; McCartney, Alan; Ferguson, Fiona; Rowe, Michael T

    2002-02-01

    Raw cows' milk naturally infected with Mycobacterium paratuberculosis was pasteurized with an APV HXP commercial-scale pasteurizer (capacity 2,000 liters/h) on 12 separate occasions. On each processing occasion, milk was subjected to four different pasteurization treatments, viz., 73 degrees C for 15 s or 25 s with and without prior homogenization (2,500 lb/in(2) in two stages), in an APV Manton Gaulin KF6 homogenizer. Raw and pasteurized milk samples were tested for M. paratuberculosis by immunomagnetic separation (IMS)-PCR (to detect the presence of bacteria) and culture after decontamination with 0.75% (wt/vol) cetylpyridinium chloride for 5 h (to confirm bacterial viability). On 10 of the 12 processing occasions, M. paratuberculosis was detectable by IMS-PCR, culture, or both in either raw or pasteurized milk. Overall, viable M. paratuberculosis was cultured from 4 (6.7%) of 60 raw and 10 (6.9%) of 144 pasteurized milk samples. On one processing day, in particular, M. paratuberculosis appeared to have been present in greater abundance in the source raw milk (evidenced by more culture positives and stronger PCR signals), and on this occasion, surviving M. paratuberculosis bacteria were isolated from milk processed by all four heat treatments, i.e., 73 degrees C for 15 and 25 s with and without prior homogenization. On one other occasion, surviving M. paratuberculosis bacteria were isolated from an unhomogenized milk sample that had been heat treated at 73 degrees C for 25 s. Results suggested that homogenization increases the lethality of subsequent heat treatment to some extent with respect to M. paratuberculosis, but the extended 25-s holding time at 73 degrees C was found to be no more effective at killing M. paratuberculosis than the standard 15-s holding time. This study provides clear evidence that M. paratuberculosis bacteria in naturally infected milk are capable of surviving commercial high-temperature, short-time pasteurization if they are present in raw milk in sufficient numbers. PMID:11823197

  3. Miner's rule revisited

    NASA Astrophysics Data System (ADS)

    Schuetz, W.; Heuler, P.

    1994-03-01

    In the first sections, the requirements to be met by hypotheses for fatigue life prediction (including those for the crack initiation and crack propagation phases) are discussed in detail. These requirements are shown to be different for 'scientific' and for 'industrial' fatigue life prediction. Aspects with regard to an assessment of fatigue life prediction hypotheses are discussed. The last section presents the results of a large cooperative program between IABG and several automobile manufacturers, in which Miner's Rule in several versions was assessed against spectrum tests with five different actual automobile components: forged steel stub axle; forged steel stub axle, induction hardened; sheet steel welded rear axle (front wheel drive car); cast aluminum wheel; and welded sheet steel wheel. Since up to 80 components each were available, and two different, but typical, automotive stress-time histories were employed, the assessment was very thorough, avoiding many of the drawbacks of previous assessments. It is shown that damage sums to failure were usually far below 1.0; they also depended on the component in question, the aluminum wheel resulting in the lowest damage sums to failure; the damage sums to failure where always lower for a mild spectrum than for a severe one; and the influence of spectrum variation was predicted best - among the hypotheses tested - by use of a recent proposal of Zenner and Liu.

  4. Radiolytic Cryovolcanism Revisited

    NASA Technical Reports Server (NTRS)

    Cooper, John F.

    2011-01-01

    Location of Enceladus within the inner magnetosphere of Saturn makes it likely that energetic electron irradiation, ion-neutral chemistry of the emergent cryovolcanic plume gas, and resultant radiolytic modification of surface ice composition could impact long-term evolution of molecular composition in the global ice crust. Thermally-driven convection of ice in the south polar terrain would bring radiolytic oxidant products into contact with subsurface reservoirs of primordial organics on million-year time scales. The chemical reactions leading to CO2 gas production as a primary gas-piston driver of cryovolcanic activity would be exponentially elevated in the warm-ice margins of a heated fluid. The fluid temperature is typically assumed to be below 273 K but could be much higher in a gas-pressurized deep subsurface environment. The Perrier Ocean model has demonstrated how a CO2-loaded fluid could account for the observed jets, while the heat content of the fluid arising from the moon's deeper interior could support high levels of chemical reactivity in the thermal margins. Since mass loss and tidal dissipation arguments do not support continuous activity over billions of years, the activity is likely very episodic so that even low-level energy sources including irradiation-driven radiolysis of surface ices could substantially contribute to the chemical dynamics of the activity apparently now in high phase. A multi-phase thermochemical model, and supporting laboratory measurements of temperature-dependent reaction rates, are needed to investigate these potentially complex processes.

  5. DROMO Propagator Revisited

    NASA Astrophysics Data System (ADS)

    Urrutxua, H.; Sanjurjo-Rivo, M.; Pelez, J.

    2013-12-01

    In year 2000 a house-made orbital propagator was developed by the SDGUPM (former Grupo de Dinmica de Tethers) based in a set of redundant variables including Euler parameters. This propagator was called DROMO. and it was mainly used in numerical simulations of electrodynamic tethers. It was presented for the first time in the international meeting V Jornadas de Trabajo en Mecnica Celeste, held in Albarracn, Spain, in 2002 (see reference 1). The special perturbation method associated with DROMO can be consulted in the paper.2 In year 1975, Andre Deprit in reference 3 proposes a propagation scheme very similar to the one in which DROMO is based, by using the ideal frame concept of Hansen. The different approaches used in references 3 and 2 gave rise to a small controversy. In this paper we carried out a different deduction of the DROMO propagator, underlining its close relation with the Hansen ideal frame concept, and also the similarities and the differences with the theory carried out by Deprit in 3. Simultaneously we introduce some improvements in the formulation that leads to a more synthetic propagator.

  6. The Armstrong experiment revisited

    NASA Astrophysics Data System (ADS)

    Fuchs, Elmar C.; Wexler, Adam D.; Paulitsch-Fuchs, Astrid H.; Agostinho, Luewton L. F.; Yntema, Doekle; Woisetschlger, Jakob

    2014-04-01

    When a high-voltage direct-current is applied to two beakers filled with water or polar liquid dielectrica, a horizontal bridge forms between the two beakers. This experiment was first carried out by Lord Armstrong in 1893 and then forgotten until recently. Such bridges are stable by the action of electrohydrodynamic (EHD) forces caused by electric field gradients counteracting gravity. Due to these gradients a permanent pumping of liquid from one beaker into the other is observed. At macroscopic scale several of the properties of a horizontal water bridge can be explained by modern electrohydrodynamics, analyzing the motion of fluids in electric fields. Whereas on the molecular scale water can be described by quantum mechanics, there is a conceptual gap at mesoscopic scale which is bridged by a number of theories including quantum mechanical entanglement and coherent structures in water - theories that we discuss here. Much of the phenomenon is already understood, but even more can still be learned from it, since such "floating" liquid bridges resemble a small high voltage laboratory of their own: The physics of liquids in electric fields of some kV/cm can be studied, even long time experiments like neutron or light scattering are feasible since the bridge is in a steady-state equilibrium and can be kept stable for hours. It is also an electro-chemical reactor where compounds are transported through by the EHD flow, enabling the study of electrochemical reactions under potentials which are otherwise not easily accessible. Last but not least the bridge provides the experimental biologist with the opportunity to expose living organisms such as bacteria to electric fields without killing them, but with a significant influence on their behavior, and possibly, even on their genome.

  7. Hotspot swells revisited

    NASA Astrophysics Data System (ADS)

    King, Scott D.; Adam, Claudia

    2014-10-01

    The first attempts to quantify the width and height of hotspot swells were made more than 30 years ago. Since that time, topography, ocean-floor age, and sediment thickness datasets have improved considerably. Swell heights and widths have been used to estimate the heat flow from the core-mantle boundary, constrain numerical models of plumes, and as an indicator of the origin of hotspots. In this paper, we repeat the analysis of swell geometry and buoyancy flux for 54 hotspots, including the 37 considered by Sleep (1990) and the 49 considered by Courtillot et al. (2003), using the latest and most accurate data. We are able to calculate swell geometry for a number of hotspots that Sleep was only able to estimate by comparison with other swells. We find that in spite of the increased resolution in global bathymetry models there is significant uncertainty in our calculation of buoyancy fluxes due to differences in our measurement of the swells width and height, the integration method (volume integration or cross-sectional area), and the variations of the plate velocities between HS2-Nuvel1a (Gripp and Gordon, 1990) and HS3-Nuvel1a (Gripp and Gordon, 2002). We also note that the buoyancy flux for Pacific hotspots is in general larger than for Eurasian, North American, African and Antarctic hotspots. Considering that buoyancy flux is linearly related to plate velocity, we speculate that either the calculation of buoyancy flux using plate velocity over-estimates the actual vertical flow of material from the deep mantle or that convection in the Pacific hemisphere is more vigorous than the Atlantic hemisphere.

  8. Potential Confounding of Particulate Mater on the Short-Term Association Between Ozone and Mortality in Multi-Site Time Series Studies

    EPA Science Inventory

    BACKGROUND: A critical question regarding the association between short-term exposure to ozone and mortality is the extent to which this relationship is confounded by ambient exposure to particles....

  9. MetaVelvet: An Extension of Velvet Assembler to de novo Metagenome Assembly from Short Sequence Reads (Metagenomics Informatics Challenges Workshop: 10K Genomes at a Time)

    SciTech Connect

    Sakakibara, Yasumbumi [Keio University] [Keio University

    2011-10-13

    Keio University's Yasumbumi Sakakibara on "MetaVelvet: An Extension of Velvet Assembler to de novo Metagenome Assembly from Short Sequence Reads" at the Metagenomics Informatics Challenges Workshop held at the DOE JGI on October 12-13, 2011.

  10. MetaVelvet: An Extension of Velvet Assembler to de novo Metagenome Assembly from Short Sequence Reads (Metagenomics Informatics Challenges Workshop: 10K Genomes at a Time)

    ScienceCinema

    Sakakibara, Yasumbumi [Keio University

    2013-01-22

    Keio University's Yasumbumi Sakakibara on "MetaVelvet: An Extension of Velvet Assembler to de novo Metagenome Assembly from Short Sequence Reads" at the Metagenomics Informatics Challenges Workshop held at the DOE JGI on October 12-13, 2011.

  11. Revisiting characteristic impedance and its definition of microstrip line with a self-calibrated 3-D MoM scheme

    Microsoft Academic Search

    Lei Zhu; Ke Wu

    1998-01-01

    Characteristic impedance and its definition are revisited and discussed for microstrip line with a self-calibrated three-dimensional (3-D) method of moments (MoM). This 3-D MoM accommodates a scheme called short-open calibration (SOC) so that potential parasitic effects brought by the impressed voltage excitation and other relevant factors can be effectively removed. In this way, the characteristic impedance can be accurately defined

  12. A spatially disaggregated time-series analysis of the short-term effects of particulate matter exposure on mortality in Chennai, India

    Microsoft Academic Search

    Kalpana Balakrishnan; Bhaswati Ganguli; Santu Ghosh; Sankar Sambandam; Sugata Sen Roy; Aditya Chatterjee

    The global burden of disease due to air pollution is concentrated in the rapidly developing counties of Asia, but a recent\\u000a meta-analysis found that relatively few studies on short-term exposure to air pollution and mortality have been performed\\u000a in these countries, including India. Local evidence on the effects of short-term exposures to air pollutants on mortality\\u000a and cardio-respiratory morbidity in

  13. Gut-Homing Conventional Plasmablasts and CD27? Plasmablasts Elicited after a Short Time of Exposure to an Oral Live-Attenuated Shigella Vaccine Candidate in Humans

    PubMed Central

    Toapanta, Franklin R.; Simon, Jakub K.; Barry, Eileen M.; Pasetti, Marcela F.; Levine, Myron M.; Kotloff, Karen L.; Sztein, Marcelo B.

    2014-01-01

    Currently, there is no licensed Shigella vaccine; however, various promising live-attenuated vaccine candidates have emerged, including CVD1208S (?guaBA, ?set, ?sen S. flexneri 2a), which was shown to be safe and immunogenic in Phase 1 clinical trials. Here, we report the immune responses elicited in an outpatient Phase 2 clinical trial in which subjects were vaccinated with CVD 1208S. Oral immunization with CVD 1208S elicited high anti-S. flexneri 2a LPS and IpaB antibody responses as well as an acute plasmablast (PB) infiltration in peripheral blood 7?days after immunization. PB sorted based on their expression of homing molecules confirmed that cells expressing integrin ?4?7 alone or in combination with CD62L were responsible for antibody production (as measured by ELISpot). Furthermore, using high-color flow-cytometry, on day 7 after immunization, we observed the appearance of conventional PB (CPB, CD19dim CD20? CD27+high CD38+high CD3?), as well as a PB population that did not express CD27 (CD27? PB; pre-plasmablasts). The pattern of individual or simultaneous expression of homing markers (integrin ?4?7, CD62L, CXCR3, and CXCR4) suggested that CPB cells homed preferentially to the inflamed gut mucosa. In contrast, ~50% CD27? PB cells appear to home to yet to be identified peripheral lymphoid organs or were in a transition state preceding integrin ?4?7 upregulation. In sum, these observations demonstrate that strong immune responses, including distinct PB subsets with the potential to home to the gut and other secondary lymphoid organs, can be elicited after a short time of exposure to a shigella oral vaccine. PMID:25191323

  14. Effects of different inorganic arsenic species in Cyprinus carpio (Cyprinidae) tissues after short-time exposure: bioaccumulation, biotransformation and biological responses.

    PubMed

    Ventura-Lima, Juliane; Fattorini, Daniele; Regoli, Francesco; Monserrat, Jos M

    2009-12-01

    Differences in the toxicological and metabolic pathway of inorganic arsenic compounds are largely unknown for aquatic species. In the present study the effects of short-time and acute exposure to As(III) and As(V) were investigated in gills and liver of the common carp, Cyprinus carpio (Cyprinidae), measuring accumulation and chemical speciation of arsenic, and the activity of glutathione-S-transferase omega (GST Omega), the rate limiting enzyme in biotransformation of inorganic arsenic. Oxidative biomarkers included antioxidant defenses (total glutathione-S-transferases, glutathione reductase, glutathione, and glucose-6-phosphate dehydrogenase), total scavenging capacity toward peroxyl radicals, reactive oxygen species (ROS) measurement and lipid peroxidation products. A marked accumulation of arsenic was observed only in gills of carps exposed to 1000 ppb As(V). Also in gills, antioxidant responses were mostly modulated through a significant induction of glucose-6-phosphate dehydrogenase activity which probably contributed to reduce ROS formation; however this increase was not sufficient to prevent lipid peroxidation. No changes in metal content were measured in liver of exposed carps, characterized by lower activity of GST Omega compared to gills. On the other hand, glutathione metabolism was more sensitive in liver tissue, where a significant inhibition of glutathione reductase was concomitant with increased levels of glutathione and higher total antioxidant capacity toward peroxyl radicals, thus preventing lipid peroxidation and ROS production. The overall results of this study indicated that exposure of C. carpio to As(III) and As(V) can induce different responses in gills and liver of this aquatic organism. PMID:19632019

  15. Time-series variations of the short-lived Ra in coastal waters: implying input of SGD to the coastal zone of Da-Chia River, Taichung, Taiwan

    NASA Astrophysics Data System (ADS)

    Hsu, Feng-Hsin; Su, Chih-Chieh; Lin, In-Tain; Huh, Chih-An

    2015-04-01

    Submarine groundwater discharge (SGD) has been recognized as an important pathway for materials exchanging between land and sea. Input of SGD carries the associated nutrients, trace metals, and inorganic carbon that may makes great impacts on ecosystem in the coastal zone. Due to the variability of SGD magnitude, it is difficult to estimate the flux of those associated materials around the world. Even in the same area, SGD magnitude also varies in response to tide fluctuation and seasonal change on hydraulic gradient. Thus, long-term investigation is in need. In Taiwan, the SGD study is rare and the intrusion of seawater in the coastal aquifer is emphasized in previous studies. According to the information from Hydrogeological Data Bank (Central Geological Survey, MOEA), some areas still show potentiality of SGD. Here, we report the preliminary investigation result of SGD at Gaomei Wildlife Conservation Area which located at the south of the Da-Chia River mouth. This study area is characterized by a great tidal rang and a shallow aquifer with high groundwater recharge rate. Time-series measurement of the short-lived Ra in surface water was done in both dry and wet seasons at a tidal flat site and shows different trends of excess Ra-224 between dry and wet seasons. High excess Ra-224 activities (>20 dpm/100L) occurred at high tide in dry season but at low tide in wet season. The plot of salinity versus excess Ra-224, showing non-conservative curve, suggests that high excess Ra-224 activities derive from desorption in dry season but from SGD input in wet season.

  16. Arabic Short Text Compression

    Microsoft Academic Search

    Eman Omer; Khalaf Khatatneh

    Problem statement: Text compression permits representing a document by using less space. This is useful not only to save disk space, but more importantly, to save disk transfer and network transmission time. With the continues incre ase in the number of Arabic short text messages sent by mobile phones, the use of a suitable compre ssion scheme would allow users

  17. Axion cosmology revisited

    SciTech Connect

    Wantz, Olivier; Shellard, E. P. S. [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

    2010-12-15

    The misalignment mechanism for axion production depends on the temperature-dependent axion mass. The latter has recently been determined within the interacting instanton liquid model, and provides for the first time a well-motivated axion mass for all temperatures. We reexamine the constraints placed on the axion parameter space in the light of this new mass function. Taking this mass at face value, we find an accurate and updated constraint f{sub a{<=}}2.8({+-}2)x10{sup 11} GeV or m{sub a{>=}}21({+-}2) {mu}eV from the misalignment mechanism in the classic axion window (thermal scenario). However, this is superseded by axion string radiation which leads to f{sub a} < or approx. 3.2{sub -2}{sup +4}x10{sup 10} GeV or m{sub a} > or approx. 0.20{sub -0.1}{sup +0.2} meV. In this analysis, we take care to precisely compute the effective degrees of freedom and, to fill a gap in the literature, we present accurate fitting formulas. We solve the evolution equations exactly, and find that analytic results used to date generally underestimate the full numerical solution by a factor 2-3. In the inflationary scenario, axions induce isocurvature fluctuations and constrain the allowed inflationary scale H{sub I}. Taking anharmonic effects into account, we show that these bounds are actually weaker than previously computed. Considering the fine-tuning issue of the misalignment angle in the whole of the anthropic window, we derive new bounds which open up the inflationary window near {theta}{sub a{yields}{pi}}. In particular, we find that inflationary dark matter axions can have masses as high as 0.01-1 meV, covering the whole thermal axion range, with values of H{sub I} up to 10{sup 9} GeV. Quantum fluctuations during inflation exclude dominant dark matter axions with masses above m{sub a} < or approx. 1 meV.

  18. Lunar Paleomagnetism Revisited

    NASA Astrophysics Data System (ADS)

    Fuller, M.; Weiss, B. P.

    2009-12-01

    The introduction of principal component analysis by Kirschvink (1980) and the routine use of orthogonal demagnetization plotting techniques brought about a fundamental improvement in the analysis of demagnetization data. Unfortunately, principal component analysis was not available when much of the early paleomagnetic work was done on the Apollo samples. We have therefore carried out a reanalysis of past lunar sample demagnetization data using the principal component analysis technique combined with orthogonal demagnetization plots. Our results show that AF demagnetization of some samples reveals a characteristic remanent magnetization. Other samples were clearly not demagnetized to sufficiently high fields to identify a characteristic remanent magnetization. In retrospect, it is clear that the failure to carry out AF demagnetization to much more than ~50 mT was a critical problem with the early work. High fields are particularly important for separating the effects of shock from any possible primary thermoremanent magnetization (TRM) acquired on the lunar surface. Results from Gattacceca et al. (2007, 2008) document shock remanent magnetization (SRM) acquired in only a few GPa, which is below the level of shock currently identifiable using petrologic techniques. Moreover these SRMs were stable against AF demagnetization to ~20-30 mT. However, they were softer than TRM in the same samples. Few mare basalts show evidence of extreme shock sufficient to generate maskelynite, but some show mild or intense fracturing, suggesting shock of up to ~10 - 15 GPa. Hence recognition of SRM is essential for satisfactory interpretation of the natural remanent magnetization. With the lunar samples, this is best done at the present time by AF demagnetization because it avoids the difficulties sample alteration during heating and because SRM can have a broad range of blocking temperatures and yet be restricted to mainly low coercivity grains. Examples of principal component analyses on AF demagnetization data will be shown. While many samples fail to reveal an interpretable characteristic remanent magnetization, there are other samples which appear to have retained a primary NRM from when they cooled on the lunar surface in a lunar field.

  19. Advanced chemistry-transport modeling and observing systems allow daily air quality observations, short-term forecasts, and real-time analyses of air quality at the global and

    E-print Network

    Paris-Sud XI, Universit de

    Advanced chemistry-transport modeling and observing systems allow daily air quality observations, short-term forecasts, and real-time analyses of air quality at the global and European scales control measures that could be taken for managing such episodes, European-scale air quality forecasting

  20. Constraining the Time-Scale of Interaction of Sea Ice Sediments and Surface Sea Water in the Arctic Ocean Using Short-Lived Radionuclide Tracers

    NASA Astrophysics Data System (ADS)

    Baskaran, M.; Andersson, P. S.; Jweda, J.; Dahlqvist, R.; Ketterer, M. E.

    2007-12-01

    We measured the activities of short-lived radionuclides (Th-234, Be-7, Po-210, Pb-210, Cs-137, Th-234, Ra-226 and Ra-228) and concentrations of several elements (Be, Pb, Fe, Al, Co, Ni, Cu and Zn) on a suite of ice-rafted sediments (IRS) collected during BERINGIA-2005 in the Western Arctic Ocean. A suite of water samples were also collected and analyzed for particulate and dissolved Be-7, Po-210, Pb-210, Th-234, Ra-226 and Ra-228. The activities of Be-7 and Pb-210 in the IRS are 1-2 orders of magnitude higher than those reported in the source sediments. Presence of excess Th-234 in the IRS indicates that the removal of Th-234 from surface seawater took place on time scales comparable to the mean-life of Th-234. While the Po-210/Pb-210 activity ratios in the source sediments (1.0) and the atmospheric depositional input (~0.1) are known, varying ratios of 0.78 to 1.0 were found in the IRS. This ratio can be utilized to obtain the residence time of the IRS in sea ice. The activity of Ra-226 and Ra-228 in all the IRS is nearly constant (within a factor of 1.6) and are comparable to the benthic sediments in the source region. The activities of atmospherically-delivered radionuclides, Be-7 and Pb-210, in IRS varied by factors of ~4.5 and 9, respectively, and this variation is attributed to differences in the extent of interaction of surface water with IRS and differences in the mean-lives of these nuclides. While significant enrichment of Be-7 and Pb-210 has been found, there is no enrichment of stable Pb or Be. The Al-normalized enrichment factor for elements measured (Co, Ni, Cu, Zn, Pb and Be) indicate that there is no significant enrichment of these elements, with Al-normalized enrichment factors less than 1.3.