Science.gov

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

  2. Revisiting the potential of time-domain indexes in short-term HRV analysis.

    PubMed

    Balocchi, Rita; Cantini, Federico; Varanini, Maurizio; Raimondi, Gianfranco; Legramante, Jacopo M; Macerata, Alberto

    2006-10-01

    In the context of HRV analysis, we evaluated the information content of two measures that can easily be derived from the classical RR time-domain indexes. The two measures are: 1) the ratio sd/rmssd, where sd is the RR standard deviation and rmssd is the root mean square of squared differences of consecutive RR beats; and 2) the ratio sd2/sd1, where sd2 and sd1 are extracted from the Poincaré plot and represent the transversal and longitudinal dispersion of the cloud of points (RR(i),RR(i)(+1)). We compared the performance of the two measures with that of the classical LF/HF ratio in a group of healthy subjects who underwent a 70 degrees upright tilt test. The goodness of the results obtained by the two measures, the simplicity of their calculation and their applicability free from a priori assumptions on the characteristics of the data are proposed to the attention of the community involved in the HRV analysis as a possible alternative to the LF/HF ratio.

  3. Revisiting the Physics of Long - Short Interaction

    NASA Astrophysics Data System (ADS)

    Diamond, P. H.; Katt, N. T.; Katt, G. T.

    2016-10-01

    An important example of disparate scale interaction in confined plasmas is that of the interplay of larger scale drift wave turbulence with smaller scale ETG turbulence. Here, we examine electron heat avalanches in the presence of both drift wave and ETG activity. We explore: i.) the rapid release of ETG to the passage of a larger scale avalanche. The ETG has the effect of limiting the sharpness of the crest of the avalanche by switching on rapid parasitic transport. This suggests that should the profiles be close to ETG marginality, the small scale modes will sharply inhibit the penetration of drift wave avalanches into that zone. Transport will occur primarily via the ETG, on the tilted crests of the large scale drift wave avalanches. ii.) the interplay of two response times (drift wave and ETG) relating the instantaneous and mean heat fluxes. In particular, the instantaneous flux can relax to mean flux on either of the (faster) ETG time scale or the (slower) drift wave time scale, depending on which is excited. These combine to yield a multi-time-scale telegraph equation for the heat avalanche. This material is based upon work supported by the U.S. Department of Energy, Office of Fusion Energy Sciences, under Award Nos. DE-FG02-04ER54738 and DE-SC0008378.

  4. A short revisit to Kuo-Brown effective interactions

    NASA Astrophysics Data System (ADS)

    Wang, XiaoBao; Dong, GuoXiang

    2015-10-01

    This paper is a short revisit to Kuo-Brown effective interaction derived from the Hamada-Johnston nucleon-nucleon potential, done by Gerry Brown and Tom Kuo. This effective interaction, derived in year 1966, is the first attempt to describe nuclear structure properties from the free nucleon-nucleon potential. Nowadays much progress has been achieved for the effective interactions in shell model. We would compare the effective interactions obtained in the 1966 paper with up-to-date shell-model interactions in sd-shell and pf-shell model space. Recent knowledge of effective interactions on nuclear structure, can also be traced in the Kuo- Brown effective interaction, i.e., the universal roles of central and tensor forces, which reminds us that such discovery should be noticed much earlier.

  5. The effect of time ordering revisited

    SciTech Connect

    Rosato, J.; Boland, D.; Capes, H.; Marandet, Y.; Stamm, R.

    2008-10-22

    The effects of time ordering on line shapes are investigated for the dynamic ionic broadening of the Lyman alpha line in hydrogen plasmas. The difference between calculations with and without time ordering is calculated for an electric field created by a single particle, and for a thermal average over plasma configurations with moderate temperature and density.

  6. Time to Revisit the Heterogeneous Telescope Network

    NASA Astrophysics Data System (ADS)

    Hessman, F. V.

    The "Heterogeneous Telescope Network" (HTN) was founded in 2005 as a loose collaboration of people somehow associated with robotic telescopes and/or projects interested in the transient universe. Other than being a very interesting forum for the exchange of ideas, the only lasting contribution of the HTN was a proposed protocol for the operation of a loose e-market for the exchange of telescope time (Allan et al. 2006; White & Allan 2007). Since the last formal meeting in 2007, the HTN has gone into a "Dornröschenschlaf" (a better word than "hibernation") : the players and interest are there, but the public visibility and activity is not. Although the participants knew and know that global networking is the way of the future for many types of science, various things have kept the HTN from taking the idea and actually implementing it: work on simply getting one's own system to work (e.g. myself), career paths of major players (e.g. Allan), dealing with the complexity of ones' own network (TALONS, RoboNet, LCO), and - most importantly - no common science driver big enough to push the participants to try it in earnest. Things have changed, however: robotic telescopes have become easier to create and operate, private networks have matured, large-scale consortia have become more common, event reporting using VOEvent has become the global standard and has a well-defined infrastructure, and large-scale sources of new objects and events are operating or will soon be operating (OGLE, CSS, Pan-STARRs, GAIA). I will review the scientific and sociological prospects for re-invigorating the HTN idea and invite discussion.

  7. 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.

  8. The residence time of water in the atmosphere revisited

    NASA Astrophysics Data System (ADS)

    van der Ent, Ruud J.; Tuinenburg, Obbe A.

    2017-02-01

    This paper revisits the knowledge on the residence time of water in the atmosphere. Based on state-of-the-art data of the hydrological cycle we derive a global average residence time of 8.9 ± 0.4 days (uncertainty given as 1 standard deviation). We use two different atmospheric moisture tracking models (WAM-2layers and 3D-T) to obtain atmospheric residence time characteristics in time and space. The tracking models estimate the global average residence time to be around 8.5 days based on ERA-Interim data. We conclude that the statement of a recent study that the global average residence time of water in the atmosphere is 4-5 days, is not correct. We derive spatial maps of residence time, attributed to evaporation and precipitation, and age of atmospheric water, showing that there are different ways of looking at temporal characteristics of atmospheric water. Longer evaporation residence times often indicate larger distances towards areas of high precipitation. From our analysis we find that the residence time over the ocean is about 2 days less than over land. It can be seen that in winter, the age of atmospheric moisture tends to be much lower than in summer. In the Northern Hemisphere, due to the contrast in ocean-to-land temperature and associated evaporation rates, the age of atmospheric moisture increases following atmospheric moisture flow inland in winter, and decreases in summer. Looking at the probability density functions of atmospheric residence time for precipitation and evaporation, we find long-tailed distributions with the median around 5 days. Overall, our research confirms the 8-10-day traditional estimate for the global mean residence time of atmospheric water, and our research contributes to a more complete view of the characteristics of the turnover of water in the atmosphere in time and space.

  9. Girl Number 20 Revisited: Feminist Literacies in New Hard Times

    ERIC Educational Resources Information Center

    Gonick, Marnina

    2007-01-01

    This paper revisits the question of "voice" in the context of neo-liberal social and educational reform. "Voice" has been one of the key concepts of feminist and critical pedagogies in the theory and practice of producing social transformation. I argue in this paper, that the political effectiveness of this concept needs to be…

  10. 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

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

    PubMed

    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.

  12. Transient nanobubbles in short-time electrolysis.

    PubMed

    Svetovoy, Vitaly B; Sanders, Remco G P; Elwenspoek, Miko C

    2013-05-08

    Water electrolysis in a microsystem is observed and analyzed on a short-time scale of ∼10 μs. The very unusual properties of the process are stressed. An extremely high current density is observed because the process is not limited by the diffusion of electroactive species. The high current is accompanied by a high relative supersaturation, S > 1000, that results in homogeneous nucleation of bubbles. On the short-time scale only nanobubbles can be formed. These nanobubbles densely cover the electrodes and aggregate at a later time to microbubbles. The effect is significantly intensified with a small increase of temperature. Application of alternating polarity voltage pulses produces bubbles containing a mixture of hydrogen and oxygen. Spontaneous reaction between gases is observed for stoichiometric bubbles with sizes smaller than ∼150 nm. Such bubbles disintegrate violently affecting the surfaces of the electrodes.

  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 τ as M ∝M0τθ with a universal initial-slip exponent θ. For the one-dimensional transverse-field Ising model, we estimate θ 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. Short-time diffusivity of dicolloids

    NASA Astrophysics Data System (ADS)

    Panczyk, Mark M.; Wagner, Norman J.; Furst, Eric M.

    2014-06-01

    The short-time diffusivity of dicolloid particles as a function of particle volume fraction ϕ from 0.01≤ϕ≤0.6 is measured using diffusing wave spectroscopy. The diffusivities of symmetric and asymmetric dicolloids are compared with similarly sized spheres. The short-time diffusivity is independent of salt concentration and decreases with increasing volume fraction for both spheres and asymmetric dicolloids. Symmetric dicolloids have a higher diffusivity than spheres at similar volume fractions. This difference is accounted for by rescaling the dicolloid volume fraction based on the ratio of the random close-packing volume fractions of spheres and dicolloids. Finally, a useful method is provided for calculating the diffusivity of symmetric dicolloid particles of arbitrary aspect ratio based on the calculated hydrodynamic resistance of Zabarankin [Proc. R. Soc. A 463, 2329 (2007), 10.1098/rspa.2007.1872].

  15. Method analyzes pressure for short flow times

    SciTech Connect

    Soliman, M. ); Petak, K. )

    1990-04-30

    Pressure build-up after short producing times and pressure surges can be analyzed. The method employs the derivative plot and does not require prior knowledge of initial reservoir pressure that may be calculated using a Cartesian plot. Field use of the new technique has proven its superiority to previously used methods, and has shown the necessity of using highly accurate data to achieve desired results.

  16. Clustering Short Time-Series Microarray

    NASA Astrophysics Data System (ADS)

    Ping, Loh Wei; Hasan, Yahya Abu

    2008-01-01

    Most microarray analyses are carried out on static gene expressions. However, the dynamical study of microarrays has lately gained more attention. Most researches on time-series microarray emphasize on the bioscience and medical aspects but few from the numerical aspect. This study attempts to analyze short time-series microarray mathematically using STEM clustering tool which formally preprocess data followed by clustering. We next introduce the Circular Mould Distance (CMD) algorithm with combinations of both preprocessing and clustering analysis. Both methods are subsequently compared in terms of efficiencies.

  17. Short rise time intense electron beam generator

    DOEpatents

    Olson, Craig L.

    1987-01-01

    A generator for producing an intense relativistic 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.

  18. 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.

  19. Hurst exponents for short time series

    NASA Astrophysics Data System (ADS)

    Qi, Jingchao; Yang, Huijie

    2011-12-01

    A concept called balanced estimator of diffusion entropy is proposed to detect quantitatively scalings in short time series. The effectiveness is verified by detecting successfully scaling properties for a large number of artificial fractional Brownian motions. Calculations show that this method can give reliable scalings for short time series with length ˜102. It is also used to detect scalings in the Shanghai Stock Index, five stock catalogs, and a total of 134 stocks collected from the Shanghai Stock Exchange Market. The scaling exponent for each catalog is significantly larger compared with that for the stocks included in the catalog. Selecting a window with size 650, the evolution of scaling for the Shanghai Stock Index is obtained by the window's sliding along the series. Global patterns in the evolutionary process are captured from the smoothed evolutionary curve. By comparing the patterns with the important event list in the history of the considered stock market, the evolution of scaling is matched with the stock index series. We can find that the important events fit very well with global transitions of the scaling behaviors.

  20. Biogas from Macroalgae: is it time to revisit the idea?

    PubMed

    Hughes, Adam D; Kelly, Maeve S; Black, Kenneth D; Stanley, Michele S

    2012-11-27

    The economic and environmental viability of dedicated terrestrial energy crops is in doubt. The production of large scale biomass (macroalgae) for biofuels in the marine environment was first tested in the late 1960's. The culture attempts failed due to the engineering challenges of farming offshore. However the energy conversion via anaerobic digestion was successful as the biochemical composition of macroalgae makes it an ideal feedstock. The technology for the mass production of macroalgae has developed principally in China and Asia over the last 50 years to such a degree that it is now the single largest product of aquaculture. There has also been significant technology transfer and macroalgal cultivation is now well tried and tested in Europe and America. The inherent advantage of production of biofuel feedstock in the marine environment is that it does not compete with food production for land or fresh water. Here we revisit the idea of the large scale cultivation of macroalgae at sea for subsequent anaerobic digestion to produce biogas as a source of renewable energy, using a European case study as an example.

  1. Biogas from Macroalgae: is it time to revisit the idea?

    PubMed Central

    2012-01-01

    The economic and environmental viability of dedicated terrestrial energy crops is in doubt. The production of large scale biomass (macroalgae) for biofuels in the marine environment was first tested in the late 1960’s. The culture attempts failed due to the engineering challenges of farming offshore. However the energy conversion via anaerobic digestion was successful as the biochemical composition of macroalgae makes it an ideal feedstock. The technology for the mass production of macroalgae has developed principally in China and Asia over the last 50 years to such a degree that it is now the single largest product of aquaculture. There has also been significant technology transfer and macroalgal cultivation is now well tried and tested in Europe and America. The inherent advantage of production of biofuel feedstock in the marine environment is that it does not compete with food production for land or fresh water. Here we revisit the idea of the large scale cultivation of macroalgae at sea for subsequent anaerobic digestion to produce biogas as a source of renewable energy, using a European case study as an example. PMID:23186536

  2. Short time ahead wind power production forecast

    NASA Astrophysics Data System (ADS)

    Sapronova, Alla; Meissner, Catherine; Mana, Matteo

    2016-09-01

    An accurate prediction of wind power output is crucial for efficient coordination of cooperative energy production from different sources. Long-time ahead prediction (from 6 to 24 hours) of wind power for onshore parks can be achieved by using a coupled model that would bridge the mesoscale weather prediction data and computational fluid dynamics. When a forecast for shorter time horizon (less than one hour ahead) is anticipated, an accuracy of a predictive model that utilizes hourly weather data is decreasing. That is because the higher frequency fluctuations of the wind speed are lost when data is averaged over an hour. Since the wind speed can vary up to 50% in magnitude over a period of 5 minutes, the higher frequency variations of wind speed and direction have to be taken into account for an accurate short-term ahead energy production forecast. In this work a new model for wind power production forecast 5- to 30-minutes ahead is presented. The model is based on machine learning techniques and categorization approach and using the historical park production time series and hourly numerical weather forecast.

  3. Revisiting the Long/Soft-Short/Hard Classification of Gamma-Ray Bursts in the Fermi Era

    NASA Astrophysics Data System (ADS)

    Zhang, Fu-Wen; Shao, Lang; Yan, Jing-Zhi; Wei, Da-Ming

    2012-05-01

    We perform a statistical analysis of the temporal and spectral properties of the latest Fermi gamma-ray bursts (GRBs) to revisit the classification of GRBs. We find that the bimodalities of duration and the energy ratio (E peak/Fluence) and the anti-correlation between spectral hardness (hardness ratio (HR), peak energy, and spectral index) and duration (T 90) support the long/soft-short/hard classification scheme for Fermi GRBs. The HR-T 90 anti-correlation strongly depends on the spectral shape of GRBs and energy bands, and the bursts with the curved spectra in the typical BATSE energy bands show a tighter anti-correlation than those with the power-law spectra in the typical BAT energy bands. This might explain why the HR-T 90 correlation is not evident for those GRB samples detected by instruments like Swift with a narrower/softer energy bandpass. We also analyze the intrinsic energy correlation for the GRBs with measured redshifts and well-defined peak energies. The current sample suggests E p, rest = 2455 × (E iso/1052)0.59 for short GRBs, significantly different from that for long GRBs. However, both the long and short GRBs comply with the same E p, rest-L iso correlation.

  4. REVISITING THE LONG/SOFT-SHORT/HARD CLASSIFICATION OF GAMMA-RAY BURSTS IN THE FERMI ERA

    SciTech Connect

    Zhang Fuwen; Yan Jingzhi; Wei Daming; Shao Lang

    2012-05-10

    We perform a statistical analysis of the temporal and spectral properties of the latest Fermi gamma-ray bursts (GRBs) to revisit the classification of GRBs. We find that the bimodalities of duration and the energy ratio (E{sub peak}/Fluence) and the anti-correlation between spectral hardness (hardness ratio (HR), peak energy, and spectral index) and duration (T{sub 90}) support the long/soft-short/hard classification scheme for Fermi GRBs. The HR-T{sub 90} anti-correlation strongly depends on the spectral shape of GRBs and energy bands, and the bursts with the curved spectra in the typical BATSE energy bands show a tighter anti-correlation than those with the power-law spectra in the typical BAT energy bands. This might explain why the HR-T{sub 90} correlation is not evident for those GRB samples detected by instruments like Swift with a narrower/softer energy bandpass. We also analyze the intrinsic energy correlation for the GRBs with measured redshifts and well-defined peak energies. The current sample suggests E{sub p,rest} = 2455 Multiplication-Sign (E{sub iso}/10{sup 52}){sup 0.59} for short GRBs, significantly different from that for long GRBs. However, both the long and short GRBs comply with the same E{sub p,rest}-L{sub iso} correlation.

  5. P3 response during short-term memory retrieval revisited by a spatio-temporal analysis.

    PubMed

    Ergen, Mehmet; Yildirim, Erol; Uslu, Atilla; Gürvit, Hakan; Demiralp, Tamer

    2012-05-01

    The most reported event related potential (ERP) parameter during short-term memory retrieval has been P3 wave and the association has been built on the relation between P3 latency and reaction times. The aim of this study is to identify an ERP component that reflects the memory scanning process preceding the decision making stage which has been associated with the P3 peak. A spatiotemporal analysis was applied on the P3 and pre-P3 period of ERP responses obtained during the retrieval phase of the Sternberg paradigm with two memory load conditions (3 and 5 letters in the memory set). In the easy task condition with the fastest reaction times (positive probes of 3 letters condition), a single P3 was observed, whereas P3 was split into two peaks in responses to probe items of more demanding task conditions. The single P3 peak and the later components of the split P3 peaks displayed the typical P3 topography. On the other hand, the topographic mapping of the earlier peak of the split P3 wave and ascending part of the single P3 peak revealed a right parietal topography. The onset time of this earlier right lateralized topography was stable among all conditions but it persisted longer in the high memory load condition. We conclude that the right-lateralized positivity in the pre-P3 period reflects the memory scanning process followed by the P3 peak with midline parietal topography reflecting the decision making process.

  6. Snoddy (1926) revisited: time scales of motor learning.

    PubMed

    Stratton, Shannon M; Liu, Yeou-Teh; Hong, Siang Lee; Mayer-Kress, Gottfried; Newell, Karl M

    2007-11-01

    The authors investigated the time scales of the learning of a mirror-tracing task to reexamine G. S. Snoddy's (1926) original claim and the received theoretical view (A. Newell & P. S. Rosenbloom, 1981) that motor learning follows a power law. Adult participants (N = 16) learned the tracing task in either a normal or a reversed visual-image condition over 5 consecutive days of practice and then performed 1 day of practice 1 week later and again 1 month later. The reversed-image group's performance was poorer than that of the normal-image group throughout the practice. An exponential was the best fitting function on individual data, but the power-law function was the best fit on the group-averaged data. The findings provided preliminary evidence that 2 characteristic time scales, (a) fast, dominated by warm-up, and (b) slow, dominated by persistent change, capture individuals' performance in the learning of the mirror-tracing task.

  7. Energy state revisited. [for minimum-time aircraft climbs

    NASA Technical Reports Server (NTRS)

    Kelley, H. J.; Cliff, E. M.; Weston, A. R.

    1983-01-01

    Kaiser (1944) has introduced the concept of 'resultant height' in connection with aircraft minimum-time climbs. Its use as a state variable in trajectory work is attractive because it is a 'slower' variable than either altitude or velocity. Kelley (1972, 1973) has made an attempt to synthesize 'slow' state variables in connection with singular-perturbation procedures. In the present investigation, attempts are made to synthesize both 'fast' and 'slow' variables for the minimum-time-to-climb problem along lines explored by Kelley. Attention is given to climb equations, energy-modeling simplifications, 'slow'-variable choice, 'fast'-variable-choice considerations, a singular-perturbation analysis, the choice of a 'fast' variable, and the climb-dash problem.

  8. 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.

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

    SciTech Connect

    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.

  10. Through the mists of time: Sushrutha, an enigma revisited

    PubMed Central

    Puthumana, Philip Philip

    2009-01-01

    Sushrutha had been viewed in textbooks of plastic surgery as belonging to the caste of potters who performed surgery in India. We have examined the available source documents and other references to the technology of the period to examine this assertion and are convinced that there is no evidence to support this. The period, technology and geographic references in Sushrutha Samhitha are correlated with settled positions on these to arrive at an understanding of the time and knowledge which is described. Source of erroneous interpretation of Sushrutha as a potter is also examined and clarified. PMID:20368861

  11. 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 Å 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

  12. It's about time: revisiting temporal processing deficits in dyslexia.

    PubMed

    Casini, Laurence; Pech-Georgel, Catherine; Ziegler, Johannes C

    2017-02-27

    Temporal processing in French children with dyslexia was evaluated in three tasks: a word identification task requiring implicit temporal processing, and two explicit temporal bisection tasks, one in the auditory and one in the visual modality. Normally developing children matched on chronological age and reading level served as a control group. Children with dyslexia exhibited robust deficits in temporal tasks whether they were explicit or implicit and whether they involved the auditory or the visual modality. First, they presented larger perceptual variability when performing temporal tasks, whereas they showed no such difficulties when performing the same task on a non-temporal dimension (intensity). This dissociation suggests that their difficulties were specific to temporal processing and could not be attributed to lapses of attention, reduced alertness, faulty anchoring, or overall noisy processing. In the framework of cognitive models of time perception, these data point to a dysfunction of the 'internal clock' of dyslexic children. These results are broadly compatible with the recent temporal sampling theory of dyslexia.

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

    NASA Astrophysics Data System (ADS)

    Schneider, S.

    2006-12-01

    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.

  14. Short-time oxidation of zirconium.

    NASA Technical Reports Server (NTRS)

    Srivastava, L. P.; Archbold, T. F.

    1972-01-01

    Study of zirconium oxidation kinetics for maximum exposure times of 3 min and in the temperature range 440 to 850 C. 'Discontinuous' oxidation runs were employed whereby a specimen was inserted into the gas stream for a predetermined time, removed and weighed, and reinserted into the oxidation atmosphere. It is considered that the increase in the observed activation energy for the early stage parabolic oxidation is a manifestation of a change from an n-type oxide to a predominantly p-type oxide, in agreement with the authors' earlier conclusion (1971) based on pressure effects.

  15. Determinism test for very short time series.

    PubMed

    Binder, P-M; Igarashi, Ryu; Seymour, William; Takeishi, Candy

    2005-03-01

    A test for determinism suitable for time series shorter than 100 points is presented, and applied to numerical and observed data. The method exploits the linear d(d(0)) dependence in the expression d(t) approximately d(0)e(lambda t) which describes the growth of small separations between trajectories in chaotic systems.

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

    ERIC Educational Resources Information Center

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

    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…

  17. Short Vowels versus Word Familiarity in the Reading Comprehension of Arab Readers: A Revisited Issue

    ERIC Educational Resources Information Center

    Seraye, Abdullah M.

    2016-01-01

    Arab readers, both beginning and advanced, are encouraged to read and accustomed to unvowelized and undiacriticized texts. Previous literature claimed that the presence of short vowels in the text would facilitate the reading comprehension of both beginning and advanced Arab readers. However, with a claimed strict controlling procedure, different…

  18. Controlled short residence time coal liquefaction process

    DOEpatents

    Anderson, Raymond P.; Schmalzer, David K.; Wright, Charles H.

    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.

  19. 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.

  20. Revisiting the returns-volume relationship: Time variation, alternative measures and the financial crisis

    NASA Astrophysics Data System (ADS)

    Cook, Steve; Watson, Duncan

    2017-03-01

    Following its introduction in the seminal study of Osborne (1959), a voluminous literature has emerged examining the returns-volume relationship for financial assets. The present paper revisits this relationship in an examination of the FTSE100 which extends the existing literature in two ways. First, alternative daily measures of the FTSE100 index are used to create differing returns and absolute returns series to employ in an examination of returns-volume causality. Second, rolling regression analysis is utilised to explore potential time variation in the returns-volume relationship. The findings obtained depict a hitherto unconsidered complexity in this relationship with the type of returns series considered and financial crisis found to be significant underlying factors. The implications of the newly derived results for both the understanding of the nature of the returns-volume relationship and the development of theories in connection to it are discussed.

  1. Is it time to revisit the role of psychedelic drugs in enhancing human creativity?

    PubMed

    Sessa, B

    2008-11-01

    Human creativity is difficult to define and measure, but it is undoubtedly an important cognitive process. This makes it an interesting challenge for modern neuroscientific exploration - especially given the current interest in developing cognitive enhancers for commercial and clinical uses. There are similarities between the typical traits of creative people and the subjective psychological characteristics of the psychedelic (hallucinogenic) drug experience. This phenomenon was studied in a number of small trials and case studies in the 1960s. Results were inconclusive, and the quality of these studies - by modern research standards - was merely anecdotal. Nevertheless, with today's current renaissance in psychedelic drug research and the growing interest in cognitive enhancing drugs, now may be the time to re-visit these studies with contemporary research methods.

  2. Short time-series microarray analysis: Methods and challenges

    PubMed Central

    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

  3. Short-term and long-term stability of surgically assisted rapid palatal expansion revisited

    PubMed Central

    Chamberland, Sylvain; Proffit, William R.

    2014-01-01

    Introduction The purpose of this article is to present further longitudinal data for short-term and long-term stability, following up our previous article in the surgery literature with a larger sample and 2 years of stability data. Methods Data from 38 patients enrolled in this prospective study were collected before treatment, at maximum expansion, at removal of the expander 6 months later, before any second surgical phase, at the end of orthodontic treatment, and at the 2-year follow-up, by using posteroanterior cephalograms and dental casts. Results With surgically assisted rapid palatal expansion (SARPE), the mean maximum expansion at the first molar was 7.60 ± 1.57 mm, and the mean relapse was 1.83 ± 1.83 mm (24%). Modest relapse after completion of treatment was not statistically significant for all teeth except for the maxillary first molar (0.99 ± 1.1 mm). A significant relationship (P <0.0001) was observed between the amount of relapse after SARPE and the posttreatment observation. At maximum, a skeletal expansion of 3.58 ± 1.63 mm was obtained, and this was stable. Conclusions Skeletal changes with SARPE were modest but stable. Relapse in dental expansion was almost totally attributed to lingual movement of the posterior teeth; 64% of the patients had more than 2 mm of dental changes. Phase 2 surgery did not affect dental relapse. PMID:21640889

  4. Short-Time Behavior and Criticality of Driven Lattice Gases

    NASA Astrophysics Data System (ADS)

    Basu, Urna; Volpati, Valerio; Caracciolo, Sergio; Gambassi, Andrea

    2017-02-01

    The nonequilibrium short-time critical behaviors of driven and undriven lattice gases are investigated via Monte Carlo simulations in two spatial dimensions starting from a fully disordered initial configuration. In particular, we study the time evolution of suitably defined order parameters, which account for the strong anisotropy introduced by the homogeneous drive. We demonstrate that, at short times, the dynamics of all these models is unexpectedly described by an effective continuum theory in which transverse fluctuations, i.e., fluctuations averaged along the drive, are Gaussian, irrespective of this being actually the case in the stationary state. Strong numerical evidence is provided, in remarkable agreement with that theory, both for the driven and undriven lattice gases, which therefore turn out to display the same short-time dynamics.

  5. Design of self-refocused pulses under short relaxation times.

    PubMed

    Issa, Bashar

    2009-06-01

    The effect of using self-refocused RF pulses of comparable duration to relaxation times is studied in detail using numerical simulation. Transverse magnetization decay caused by short T2 and longitudinal component distortion due to short T1 are consistent with other studies. In order to design new pulses to combat short T1 and T2 the relaxation terms are directly inserted into the Bloch equations. These equations are inverted by searching the RF solution space using simulated annealing global optimization technique. A new T2-decay efficient excitation pulse is created (SDETR: single delayed excursion T2 resistive) which is also energy efficient. Inversion pulses which improve the inverted magnetization profile and achieve better suppression of the remaining transverse magnetization are also created even when both T1 and T2 are short. This is achieved, however, on the expense of a more complex B1 shape of larger energy content.

  6. Short-time quantum propagator and Bohmian trajectories☆

    PubMed Central

    de Gosson, Maurice; Hiley, Basil

    2013-01-01

    We begin by giving correct expressions for the short-time action following the work Makri–Miller. We use these estimates to derive an accurate expression modulo Δt2 for the quantum propagator and we show that the quantum potential is negligible modulo Δt2 for a point source, thus justifying an unfortunately largely ignored observation of Holland made twenty years ago. We finally prove that this implies that the quantum motion is classical for very short times. PMID:24319313

  7. Short-time Chebyshev wave packet method for molecular photoionization

    NASA Astrophysics Data System (ADS)

    Sun, Zhaopeng; Zheng, Yujun

    2016-08-01

    In this letter we present the extended usage of short-time Chebyshev wave packet method in the laser induced molecular photoionization dynamics. In our extension, the polynomial expansion of the exponential in the time evolution operator, the Hamiltonian operator can act on the wave packet directly which neatly avoids the matrix diagonalization. This propagation scheme is of obvious advantages when the dynamical system has large Hamiltonian matrix. Computational simulations are performed for the calculation of photoelectronic distributions from intense short pulse ionization of K2 and NaI which represent the Born-Oppenheimer (BO) model and Non-BO one, respectively.

  8. 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.

  9. Speech processing based on short-time Fourier analysis

    SciTech Connect

    Portnoff, M.R.

    1981-06-02

    Short-time Fourier analysis (STFA) is a mathematical technique that represents nonstationary signals, such as speech, music, and seismic signals in terms of time-varying spectra. This representation provides a formalism for such intuitive notions as time-varying frequency components and pitch contours. Consequently, STFA is useful for speech analysis and speech processing. This paper shows that STFA provides a convenient technique for estimating and modifying certain perceptual parameters of speech. As an example of an application of STFA of speech, the problem of time-compression or expansion of speech, while preserving pitch and time-varying frequency content is presented.

  10. Signal Estimation from Short-Time Spectral Magnitude.

    DTIC Science & Technology

    1982-05-01

    reconstrutions when the short-time spectral magnitude is purposely modified for accomplishing signal processing tasks such as noise reduction and time-sale...complexity. It gen- erally requires sophisticated indexing and rather large memory space for its implementation. For example, Portnoff b. .,i to introduce...significant memory management to implement the teanique on a PDP 11150. On the other hand, Holtzman 115] aas developed an alternative implementation that

  11. Distinguishing quasiperiodic dynamics from chaos in short-time series.

    PubMed

    Zou, Y; Pazó, D; Romano, M C; Thiel, M; Kurths, J

    2007-07-01

    We propose a procedure to distinguish quasiperiodic from chaotic orbits in short-time series, which is based on the recurrence properties in phase space. The histogram of the return times in a recurrence plot is introduced to disclose the recurrence property consisting of only three peaks imposed by Slater's theorem. Noise effects on the statistics are studied. Our approach is demonstrated to be efficient in recognizing regular and chaotic trajectories of a Hamiltonian system with mixed phase space.

  12. Minimal model for short-time diffusion in periodic potentials.

    PubMed

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

    2012-12-01

    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 (nondiffusive) 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. Nontrivial 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 behavior. The simplicity of our approach means that it offers a minimal model to describe the short-time behavior of systems with hindered dynamics.

  13. Performance of multifractal detrended fluctuation analysis on short time series

    NASA Astrophysics Data System (ADS)

    López, Juan Luis; Contreras, Jesús Guillermo

    2013-02-01

    The performance of the multifractal detrended analysis on short time series is evaluated for synthetic samples of several mono- and multifractal models. The reconstruction of the generalized Hurst exponents is used to determine the range of applicability of the method and the precision of its results as a function of the decreasing length of the series. As an application the series of the daily exchange rate between the U.S. dollar and the euro is studied.

  14. NEA Mitigation Studies for Short Warning Time Scenarios

    NASA Technical Reports Server (NTRS)

    Barbee, Brent; Syal, Megan Bruck; Gisler, Galen

    2016-01-01

    This talk describes current collaborative research efforts between NASA GSFC and the Department of Energy's National Nuclear Security Administration (NNSA) national labs (Lawrence Livermore, Los Alamos, and Sandia) to design systems and frameworks for robust responses to short warning time near-Earth asteroid (NEA) scenarios, in which we would have less than 10 years to respond to an NEA on its way to impact the Earth.

  15. Permutation test for periodicity in short time series data

    PubMed Central

    Ptitsyn, Andrey A; Zvonic, Sanjin; Gimble, Jeffrey M

    2006-01-01

    Background Periodic processes, such as the circadian rhythm, are important factors modulating and coordinating transcription of genes governing key metabolic pathways. Theoretically, even small fluctuations in the orchestration of circadian gene expression patterns among different tissues may result in functional asynchrony at the organism level and may contribute to a wide range of pathologic disorders. Identification of circadian expression pattern in time series data is important, but equally challenging. Microarray technology allows estimation of relative expression of thousands of genes at each time point. However, this estimation often lacks precision and microarray experiments are prohibitively expensive, limiting the number of data points in a time series expression profile. The data produced in these experiments carries a high degree of stochastic variation, obscuring the periodic pattern and a limited number of replicates, typically covering not more than two complete periods of oscillation. Results To address this issue, we have developed a simple, but effective, computational technique for the identification of a periodic pattern in relatively short time series, typical for microarray studies of circadian expression. This test is based on a random permutation of time points in order to estimate non-randomness of a periodogram. The Permutated time, or Pt-test, is able to detect oscillations within a given period in expression profiles dominated by a high degree of stochastic fluctuations or oscillations of different irrelevant frequencies. We have conducted a comprehensive study of circadian expression on a large data set produced at PBRC, representing three different peripheral murine tissues. We have also re-analyzed a number of similar time series data sets produced and published independently by other research groups over the past few years. Conclusion The Permutated time test (Pt-test) is demonstrated to be effective for detection of periodicity in

  16. Short exposure time sensitivity of white cells to shear stress.

    PubMed

    Carter, Janell; Hristova, Katia; Harasaki, Hiroaki; Smith, W A

    2003-01-01

    White cells are a critical functional element circulating in blood. This study sheared fresh whole bovine blood in stainless steel and polymeric capillary tubes of various lengths and diameters. Flow rate was constant, resulting in a range of exposure times and shear stresses. White cell count, cell integrity (trypan blue exclusion), and phagocytic index (latex bead ingestion) were assayed. It was found that cell function declined at lower stresses than cell count. White cell count was maintained at higher stress levels at the short exposure times used here compared with the published results at longer times. This study suggests that function, not count, is the critical parameter when studying shear effects on white cells, and that, like red cells, there may be an exposure time effect and that white cell function is impacted at stresses lower than are required for hemolysis.

  17. Evaluation of Scaling Invariance Embedded in Short Time Series

    PubMed Central

    Pan, Xue; Hou, Lei; Stephen, Mutua; Yang, Huijie; Zhu, Chenping

    2014-01-01

    Scaling invariance of time series has been making great contributions in diverse research fields. But how to evaluate scaling exponent from a real-world series is still an open problem. Finite length of time series may induce unacceptable fluctuation and bias to statistical quantities and consequent invalidation of currently used standard methods. In this paper a new concept called correlation-dependent balanced estimation of diffusion entropy is developed to evaluate scale-invariance in very short time series with length . Calculations with specified Hurst exponent values of show that by using the standard central moving average de-trending procedure this method can evaluate the scaling exponents for short time series with ignorable bias () and sharp confidential interval (standard deviation ). Considering the stride series from ten volunteers along an approximate oval path of a specified length, we observe that though the averages and deviations of scaling exponents are close, their evolutionary behaviors display rich patterns. It has potential use in analyzing physiological signals, detecting early warning signals, and so on. As an emphasis, the our core contribution is that by means of the proposed method one can estimate precisely shannon entropy from limited records. PMID:25549356

  18. Evaluation of scaling invariance embedded in short time series.

    PubMed

    Pan, Xue; Hou, Lei; Stephen, Mutua; Yang, Huijie; Zhu, Chenping

    2014-01-01

    Scaling invariance of time series has been making great contributions in diverse research fields. But how to evaluate scaling exponent from a real-world series is still an open problem. Finite length of time series may induce unacceptable fluctuation and bias to statistical quantities and consequent invalidation of currently used standard methods. In this paper a new concept called correlation-dependent balanced estimation of diffusion entropy is developed to evaluate scale-invariance in very short time series with length ~10(2). Calculations with specified Hurst exponent values of 0.2,0.3,...,0.9 show that by using the standard central moving average de-trending procedure this method can evaluate the scaling exponents for short time series with ignorable bias (≤0.03) and sharp confidential interval (standard deviation ≤0.05). Considering the stride series from ten volunteers along an approximate oval path of a specified length, we observe that though the averages and deviations of scaling exponents are close, their evolutionary behaviors display rich patterns. It has potential use in analyzing physiological signals, detecting early warning signals, and so on. As an emphasis, the our core contribution is that by means of the proposed method one can estimate precisely shannon entropy from limited records.

  19. SHORT ACCELERATION TIMES FROM SUPERDIFFUSIVE SHOCK ACCELERATION IN THE HELIOSPHERE

    SciTech Connect

    Perri, S.; Zimbardo, G.

    2015-12-10

    The analysis of time profiles of particles accelerated at interplanetary shocks allows particle transport properties to be inferred. The frequently observed power-law decay upstream, indeed, implies a superdiffusive particle transport when the level of magnetic field variance does not change as the time interval from the shock front increases. In this context, a superdiffusive shock acceleration (SSA) theory has been developed, allowing us to make predictions of the acceleration times. In this work we estimate for a number of interplanetary shocks, including the solar wind termination shock, the acceleration times for energetic protons in the framework of SSA and we compare the results with the acceleration times predicted by standard diffusive shock acceleration. The acceleration times due to SSA are found to be much shorter than in the classical model, and also shorter than the interplanetary shock lifetimes. This decrease of the acceleration times is due to the scale-free nature of the particle displacements in the framework of superdiffusion. Indeed, very long displacements are possible, increasing the probability for particles far from the front of the shock to return, and short displacements have a high probability of occurrence, increasing the chances for particles close to the front to cross the shock many times.

  20. Urban air pollution by odor sources: Short time prediction

    NASA Astrophysics Data System (ADS)

    Pettarin, Nicola; Campolo, Marina; Soldati, Alfredo

    2015-12-01

    A numerical approach is proposed to predict the short time dispersion of odors in the urban environment. The model is based on (i) a three dimensional computational domain describing the urban topography at fine spatial scale (1 m) and on (ii) highly time resolved (1 min frequency) meteorological data used as inflow conditions. The time dependent, three dimensional wind velocity field is reconstructed in the Eulerian framework using a fast response finite volume solver of Navier-Stokes equations. Odor dispersion is calculated using a Lagrangian approach. An application of the model to the historic city of Verona (Italy) is presented. Results confirm that this type of odor dispersion simulations can be used (i) to assess the impact of odor emissions in urban areas and (ii) to evaluate the potential mitigation produced by odor abatement systems.

  1. 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.

  2. Short-time-interaction quantum measurement through an incoherent mediator

    SciTech Connect

    Casanova, J.; Romero, G.; Lizuain, I.; Muga, J. G.; Retamal, J. C.; Roos, C. F.; Solano, E.

    2010-06-15

    We propose a method of indirect measurements where a probe is able to read, in short interaction times, the quantum state of a remote system through an incoherent third party, hereafter called a mediator. The probe and system can interact briefly with the mediator in an incoherent state but not directly among themselves and, nevertheless, the transfer of quantum information can be achieved with robustness. We exemplify our measurement scheme with a paradigmatic example of this tripartite problem--a qubit-oscillator-qubit setup--and discuss different physical scenarios, pointing out the associated advantages and limitations.

  3. Experimental Study of Short-Time Brownian Motion

    NASA Astrophysics Data System (ADS)

    Mo, Jianyong; Simha, Akarsh; Riegler, David; Raizen, Mark

    2015-03-01

    We report our progress on the study of short-time Brownian motion of optically-trapped microspheres. In earlier work, we observed the instantaneous velocity of microspheres in gas and in liquid, verifying a prediction by Albert Einstein from 1907. We now report a more accurate test of the energy equipartition theorem for a particle in liquid. We also observe boundary effects on Brownian motion in liquid by setting a wall near the trapped particle, which changes the dynamics of the motion. We find that the velocity autocorrelation of the particle decreases faster as the particle gets closer to the wall.

  4. Target time smearing with short transmissions and multipath propagation.

    PubMed

    Harrison, Chris H

    2011-09-01

    In active sonar the target echo level is often estimated with a propagation model that adds all multipath arrivals. If the (post-correlator) transmitted pulse is short compared to the multipath time spread then there is effectively an extra loss (which may be substantial) since only a few of the paths contribute to the target echo at any one instant. This well known "time-smearing" loss is treated in a self-consistent manner with previous calculations of reverberation [Harrison, J. Acoust. Soc. Am. 114, 2744-2756 (2003)] to estimate the target response and the signal-to-reverberation-ratio. Again isovelocity water, Lambert's law, and reflection loss proportional to angle are assumed. In this important short pulse regime the target response becomes independent of boundary reflection properties but proportional to transmitted pulse length. Thus the signal-to-reverberation-ratio becomes independent of pulse length. The effect on signal-to-ambient-noise is also investigated and the resulting formulas presented in a table.

  5. A study of Venus rotation at short time scale

    NASA Astrophysics Data System (ADS)

    Cottereau, L.; Souchay, J.

    2009-12-01

    Venus which can be considered as the twin sister of the Earth in view of its global characteristics (size, density) has been the subject of many investigations to understand its slow retrograde rotation (243d) and its rather small obliquity (2°.63). Many of these studies concern the evolution of Venus rotation at very long time scales. Here we present a complete model of Venus precession and nutation based on Hamiltonian formalism for short times scales. We apply a theoretical framework already used by Kinoshita (1977) for the rigid Earth. After calculating the effects due to the gravitational tide exerted by the Sun, we also evaluate the indirect planetary effects due to the perturbation of the planets. We compare our results with those obtained by Souchay et al. (1999) on the Earth. At last we present the prospect for future studies among which are the polhody, the effects of the atmosphere and of the core-mantle interaction.

  6. Long-time vs. short-time insemination of sibling eggs

    PubMed Central

    Liu, Jing; Zhang, Xiao; Yang, Yue; Zhao, Junliang; Hao, Dayong; Zhang, Jianrui; Liu, Yanli; Wu, Wenbin; Wang, Xingling

    2016-01-01

    This study aimed to evaluate the impact of a short insemination procedure on embryo development, assess the reliability of a fertilization check prior to the appearance of pronuclei and elucidate the role of rescue intracytoplasmic sperm injection (R-ICSI). Patients who had ≥9 eggs, were aged <38 years and had normal semen samples were included. The sibling eggs of each patient were divided into two groups; one half for conventional in vitro fertilization (IVF; insemination time, 20 h) and the other half for short insemination (insemination time, 5 h). R-ICSI was performed where total fertilization failure (TFF) was deemed to have occurred in the short insemination group. In total, 2,465 eggs were included. No significant differences were found in fertilization, abnormal fertilization, embryo quality, clinical pregnancy and implantation rates between the short insemination and conventional insemination groups. In the short insemination group, R-ICSI was performed in 11 cycles (6.7%); in 6 of these cycles, fertilization occurred in the patient's eggs in the 20 h insemination group, while in the other 5 cycles, the patient's eggs were not fertilized after 20 h insemination either. Following R-ICSI, 19 of 36 eggs were normally fertilized. Subsequently, 7 embryos were transferred in 4 fresh cycles resulting in one ectopic pregnancy. In conclusion, the short insemination procedure does not improve embryo development and pregnancy rates. Short insemination combined with early R-ICSI may be a method of preventing total fertilization failure, albeit with poor accuracy. PMID:28105107

  7. Predator-prey interactions, resource depression and patch revisitation

    USGS Publications Warehouse

    Erwin, R.M.

    1989-01-01

    Generalist predators may be confronted by different types of prey in different patches: sedentary and conspicuous, cryptic (with or without refugia), conspicuous and nonsocial, or conspicuous and social. I argue that, where encounter rates with prey are of most importance, patch revisitation should be a profitable tactic where prey have short 'recovery' times (conspicuous, nonsocial prey), or where anti-predator response (e.g. shoaling) may increase conspicuousness. Predictions are made for how temporal changes in prey encounter rates should affect revisit schedules and feeding rates for the 4 different prey types.

  8. Short Lyapunov time: a method for identifying confined chaos

    NASA Astrophysics Data System (ADS)

    Winter, O. C.; Mourão, D. C.; Giuliatti Winter, S. M.

    2010-11-01

    Context. The orbital instability of minor solar system bodies (asteroids, small satellites, moonlets, and particles) is frequently studied in terms of the Lyapunov characteristic exponent (LCE). Asteroids interior to Jupiter often exihibit very short Lyapunov times, TL, and very large radial variations, becoming Jupiter's crossers and escapers. However, a few cases of asteroids with very short TL and no significant radial variation have been found. These orbits were called “confined chaos” or even “stable chaos”. This feature also appeared in the case of moonlets embedded in Saturn's F ring and disturbed by the nearby satellites Prometheus and Pandora. Aims: We present a simple approach to estimating the contribution of the radial component of the LCE to identify trajectories in the “confined chaos” regime. Methods: To estimate the radial contribution to the maximum LCE, we considered a rotating reference system in which one of the axis was aligned with the radial direction of the reference trajectory. Measuring the distance in the phase space between the two nearby orbits then allowed us to separate the contribution of the radial component from the others. We applied the method to two different dynamical systems: (a) an asteroid around the Sun disturbed by Jupiter; (b) a moonlet of Saturn's F-ring disturbed by the satellites Prometheus and Pandora. Results: In all cases, we found that the method of comparing the radial contribution of the LCE to the entire contribution allows us to correctly distinguish between confined chaos and escapers.

  9. Short and long time drop dynamics on lubricated substrates

    NASA Astrophysics Data System (ADS)

    Carlson, A.; Kim, P.; Amberg, G.; Stone, H. A.

    2013-11-01

    Liquid infiltrated solids have been proposed as functional solvent-phobic surfaces for handling single and multiphase flows. Implementation of such surfaces alters the interfacial transport phenomenon as compared to a dry substrate. To better understand the interface characteristics in such systems we study experimentally the dynamics of a pendant water drop in air that contacts a substrate coated by thin oil films. At short times the water drop is deformed by the oil that spreads onto the water-air interface, and the dynamics are characterized by inertial and viscous regimes. At late times, the the oil film under the drop relaxes either to a stable thin film or ruptures. In the thin film rupture regime, we measure the waiting time for the rupture as a function of the drop equilibrium contact angle on a dry substrate and the initial film height. The waiting time is rationalized by lubrication theory, which indicates that long-range intermolecular forces destabilize the oil-water interface and is the primary mechanism for the film drainage.

  10. Ischemic subglottic damage following a short-time intubation.

    PubMed

    Silva, Marta João; Aparício, José; Mota, Teresa; Spratley, Jorge; Ribeiro, Augusto

    2008-12-01

    The objective of this study is to report a case of ischemic subglottic damage after a short-time intubation with a large, overinflated endotracheal tube cuff in a child. The study uses individual case report. A 6-year-old boy was admitted to the pediatric intensive care unit after a head trauma intubated with a 5.5-mm inner diameter cuffed endotracheal tube overinflated with 16 ml of air that produced a pressure of more than 120 cm H2O. The endotracheal tube cuff pressure produced by inflation was reduced after 4 h. The child presented postextubation stridor with subglottic edema. Inappropriate handling of tracheal intubation without accurate measurement of endotracheal tube size and intracuff pressures of endotracheal tubes, can cause airway trauma and place patients at risk.

  11. Probabilistic eruption forecasting at short and long time scales

    NASA Astrophysics Data System (ADS)

    Marzocchi, Warner; Bebbington, Mark S.

    2012-10-01

    Any effective volcanic risk mitigation strategy requires a scientific assessment of the future evolution of a volcanic system and its eruptive behavior. Some consider the onus should be on volcanologists to provide simple but emphatic deterministic forecasts. This traditional way of thinking, however, does not deal with the implications of inherent uncertainties, both aleatoric and epistemic, that are inevitably present in observations, monitoring data, and interpretation of any natural system. In contrast to deterministic predictions, probabilistic eruption forecasting attempts to quantify these inherent uncertainties utilizing all available information to the extent that it can be relied upon and is informative. As with many other natural hazards, probabilistic eruption forecasting is becoming established as the primary scientific basis for planning rational risk mitigation actions: at short-term (hours to weeks or months), it allows decision-makers to prioritize actions in a crisis; and at long-term (years to decades), it is the basic component for land use and emergency planning. Probabilistic eruption forecasting consists of estimating the probability of an eruption event and where it sits in a complex multidimensional time-space-magnitude framework. In this review, we discuss the key developments and features of models that have been used to address the problem.

  12. 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.

  13. Revisiting doxycycline in pregnancy and early childhood – time to rebuild its reputation?

    PubMed Central

    Cross, Ruby; Ling, Clare; Day, Nicholas P. J.; McGready, Rose; Paris, Daniel H.

    2016-01-01

    ABSTRACT Introduction: Doxycycline is highly effective, inexpensive with a broad therapeutic spectrum and exceptional bioavailability. However these benefits have been overshadowed by its classification alongside the tetracyclines – class D drugs, contraindicated in pregnancy and in children under 8 years of age. Doxycycline-treatable diseases are emerging as leading causes of undifferentiated febrile illness in Southeast Asia. For example scrub typhus and murine typhus have an unusually severe impact on pregnancy outcomes, and current mortality rates for scrub typhus reach 12-13% in India and Thailand. The emerging evidence for these important doxycycline-treatable diseases prompted us to revisit doxycycline usage in pregnancy and childhood. Areas Covered: A systematic review of the available literature on doxycycline use in pregnant women and children revealed a safety profile of doxycycline that differed significantly from that of tetracycline; no correlation between the use of doxycycline and teratogenic effects during pregnancy or dental staining in children was found. Expert Opinion: The change of the US FDA pregnancy classification scheme to an evidence-based approach will enable adequate evaluation of doxycycline in common tropical illnesses and in vulnerable populations in clinical treatment trials, dosage-optimization pharmacokinetic studies and for the empirical treatment of undifferentiated febrile illnesses, especially in pregnant women and children. PMID:26680308

  14. Time Resolved Studies of Bright Short Gamma Ray Bursts in the Fermi Gamma Ray Burst Monitor

    NASA Astrophysics Data System (ADS)

    Burns, E.; Connaughton, V.; Preece, R.; Goldstein, A.

    2016-10-01

    We present preliminary results on using a Bayesian Block representation of Fermi GBM data to select intervals for time resolved analysis of short GRBs. Additionally, we search for possible precursor and extended emission in short GRBs.

  15. Safety of latex urinary catheters for the short time drainage

    PubMed Central

    Hosseinpour, Mehrdad; Noori, Saeed; Amir-Beigi, Mahdieh; Pourfakharan, Mohammad Hassan; Ehteram, Hassan; Hamsayeh, Mohadese

    2014-01-01

    Background: In this study, we attempt to identify the most appropriate catheter (silicone vs. latex) for short-term urinary catheterization. We compared the post-operative clinico-pathological complications between latex and silicone for short term catheterization in rabbits with hypospadias. Materials and Methods: Forty rabbits were used in our study to compare complications of catheterization. They were divided in two groups. Hypospadias like defect was created by a 1 cm long excision of the ventral urethra. For urethroplasty, we used tubularized incised plate technique. Latex and silicon catheters were used in groups 1 and 2, respectively. Post-operatively, routine laboratory urine test and complications (allergy, infection, bleeding) were compared in groups. Results: A total of 40 rabbits underwent hypospadias repair. Findings showed that there were no significant differences between groups based on urine test indices (P = NS). Urinary tract infection rate was 10% (2 rabbits) in latex and 0% in silicone groups (P = NS). There were no significant differences between groups regarding of cystitis grades between study groups (P = NS). Conclusion: It seems that urinary tract catheterization with latex catheters is a safe, feasible, and in-expensive procedure for short-term post-operative course in hypospadias surgery in patients without latex hypersensitivity. PMID:25125890

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

    PubMed

    Samiee, Kaveh; Kovács, Petér; 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.

  17. Effect of heating strategies on whey protein denaturation--Revisited by liquid chromatography quadrupole time-of-flight mass spectrometry.

    PubMed

    Akkerman, M; Rauh, V M; Christensen, M; Johansen, L B; Hammershøj, M; Larsen, L B

    2016-01-01

    Previous standards in the area of effect of heat treatment processes on milk protein denaturation were based primarily on laboratory-scale analysis and determination of denaturation degrees by, for example, electrophoresis. In this study, whey protein denaturation was revisited by pilot-scale heating strategies and liquid chromatography quadrupole time-of-flight mass spectrometer (LC/MC Q-TOF) analysis. Skim milk was heat treated by the use of 3 heating strategies, namely plate heat exchanger (PHE), tubular heat exchanger (THE), and direct steam injection (DSI), under various heating temperatures (T) and holding times. The effect of heating strategy on the degree of denaturation of β-lactoglobulin and α-lactalbumin was determined using LC/MC Q-TOF of pH 4.5-soluble whey proteins. Furthermore, effect of heating strategy on the rennet-induced coagulation properties was studied by oscillatory rheometry. In addition, rennet-induced coagulation of heat-treated micellar casein concentrate subjected to PHE was studied. For skim milk, the whey protein denaturation increased significantly as T and holding time increased, regardless of heating method. High denaturation degrees were obtained for T >100°C using PHE and THE, whereas DSI resulted in significantly lower denaturation degrees, compared with PHE and THE. Rennet coagulation properties were impaired by increased T and holding time regardless of heating method, although DSI resulted in less impairment compared with PHE and THE. No significant difference was found between THE and PHE for effect on rennet coagulation time, whereas the curd firming rate was significantly larger for THE compared with PHE. Micellar casein concentrate possessed improved rennet coagulation properties compared with skim milk receiving equal heat treatment.

  18. Revisiting spin-lattice relaxation time measurements for dilute spins in high-resolution solid-state NMR spectroscopy.

    PubMed

    Fu, Riqiang; Li, Jun; Cui, Jingyu; Peng, Xinhua

    2016-07-01

    Numerous nuclear magnetic resonance (NMR) measurements of spin-lattice relaxation times (T1S) for dilute spins such as (13)C have led to investigations of the motional dynamics of individual functional groups in solid materials. In this work, we revisit the Solomon equations and analyze how the heteronuclear cross relaxation between the dilute S (e.g. (13)C) and abundant I (e.g. (1)H) spins affects the measured T1S values in solid-state NMR in the absence of (1)H saturation during the recovery time. It is found theoretically that at the beginning of the S spin magnetization recovery, the existence of non-equilibrium I magnetization introduces the heteronuclear cross relaxation effect onto the recovery of the S spin magnetization and confirmed experimentally that such a heteronuclear cross relaxation effect results in the recovery overshoot phenomena for the dilute spins when T1S is on the same order of T1H, leading to inaccurate measurements of the T1S values. Even when T1S is ten times larger than T1H, the heteronuclear cross relaxation effect on the measured T1S values is still noticeable. Furthermore, this cross relaxation effect on recovery trajectory of the S spins can be manipulated and even suppressed by preparing the initial I and S magnetization, so as to obtain the accurate T1S values. A sample of natural abundance l-isoleucine powder has been used to demonstrate the T1S measurements and their corresponding measured T1C values under various experimental conditions.

  19. It is time to revisit current dietary recommendations for saturated fat.

    PubMed

    Lamarche, Benoît; Couture, Patrick

    2014-12-01

    The extent to which a high intake of saturated fat (SFA) increases the risk of cardiovascular disease (CVD) has become a highly controversial topic. Dietary SFA primarily raises low-density lipoprotein cholesterol, while having a relatively neutral impact on other key CVD risk factors. Recent epidemiological data also challenge the concept that SFA increases the risk of CVD. This short review provides arguments for the urgency to re-assess the association between dietary SFA and CVD risk in light of recent data on the subject.

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

    PubMed Central

    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 (βpH), 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 βpH 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

  1. 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

  2. A short history of time and space in immune discrimination.

    PubMed

    Langman, R E; Cohn, M

    1996-12-01

    The destructive effector functions of the immune system pose a problem that has aptly been described as 'horror autotoxicus'. This problem demands a solution that offers an effective self-nonself discrimination mechanism. Unlike all other defence mechanisms, the immune system makes the self-nonself discrimination somatically, and not at the germline level. This discrimination requires a way of separating self from nonself. Two proposals to accomplish this are based on separation in time or in space. In this paper the authors show that separation in time remains the only viable solution. A generally accepted solution to the mechanism of the self-nonself discrimination is overdue as it strongly influences the way in which much of immune regulation is interpreted.

  3. 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).

  4. Revisiting the Time Trade-off Hypothesis: Work, Organized Activities, and Academics during College

    PubMed Central

    Maggs, Jennifer L.

    2014-01-01

    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, Mage = 18.4) that was followed for 14 days within each of 7 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

  5. 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 14 days 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).

  6. Short residence time coal liquefaction process including catalytic hydrogenation

    DOEpatents

    Anderson, Raymond P.; Schmalzer, David K.; Wright, Charles 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 (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.

  7. 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.

  8. 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.

  9. High voltage electrical amplifier having a short rise time

    DOEpatents

    Christie, David J.; Dallum, Gregory E.

    1991-01-01

    A circuit, comprising an amplifier and a transformer is disclosed that produces a high power pulse having a fast response time, and that responds to a digital control signal applied through a digital-to-analog converter. The present invention is suitable for driving a component such as an electro-optic modulator with a voltage in the kilovolt range. The circuit is stable at high frequencies and during pulse transients, and its impedance matching circuit matches the load impedance with the output impedance. The preferred embodiment comprises an input stage compatible with high-speed semiconductor components for amplifying the voltage of the input control signal, a buffer for isolating the input stage from the output stage; and a plurality of current amplifiers connected to the buffer. Each current amplifier is connected to a field effect transistor (FET), which switches a high voltage power supply to a transformer which then provides an output terminal for driving a load. The transformer comprises a plurality of transmission lines connected to the FETs and the load. The transformer changes the impedance and voltage of the output. The preferred embodiment also comprises a low voltage power supply for biasing the FETs at or near an operational voltage.

  10. Time manages interference in visual short-term memory.

    PubMed

    Smith, Amy V; McKeown, Denis; Bunce, David

    2017-01-31

    Emerging evidence suggests that age-related declines in memory may reflect a failure in pattern separation, a process that is believed to reduce the encoding overlap between similar stimulus representations during memory encoding. Indeed, behavioural pattern separation may be indexed by a visual continuous recognition task in which items are presented in sequence and observers report for each whether it is novel, previously viewed (old), or whether it shares features with a previously viewed item (similar). In comparison to young adults, older adults show a decreased pattern separation when the number of items between "old" and "similar" items is increased. Yet the mechanisms of forgetting underpinning this type of recognition task are yet to be explored in a cognitively homogenous group, with careful control over the parameters of the task, including elapsing time (a critical variable in models of forgetting). By extending the inter-item intervals, number of intervening items and overall decay interval, we observed in a young adult sample (N = 35, Mage = 19.56 years) that the critical factor governing performance was inter-item interval. We argue that tasks using behavioural continuous recognition to index pattern separation in immediate memory will benefit from generous inter-item spacing, offering protection from inter-item interference.

  11. The short-time spectrum analysis of real-time sampling speech with DSP TMS320VC5416 chip

    NASA Astrophysics Data System (ADS)

    Fan, Qinru; Ren, Wen-hua

    2013-07-01

    For automatic speech recognition (ASR), the research centers mainly on algorithm of improving robust, researchers put less emphasis on realization and application of better speech algorithm. Real-time proceeding of speech recognition directly influence on its application, so real-time proceeding of speech recognition is as important as study of algorithm. Speech transform domain method is a necessary technique of speech recognition, so real-time analysis of transform domain method is necessary. In transform domain methods, the short-time spectrum analysis is simple and easy to realize, especially the short-time FFT algorithm is applied to the short-time spectrum analysis. FFT algorithm reduces multiplications greatly. For the purpose, this paper presents short-time spectrum analysis of real-time sampling speech based on FFT algorithm. We use DSP TMS320VC5416 chip and speech codec ASIC TLV320AIC23 as hardware, the real-time speech signal is acquired by ASIC TLV320AIC23. When working frequency of TMS320VC5416 is set 160 MHz and sampling frequency is 44.1 kHz, the short-time FFT is radix-2 DIF-FFT algorithm and the length of short-time window is 128, the simulation waves and data show that the short-time FFT algorithm analysis based on TMS320VC5416 chip can meet real-time of system. For estimation of proceeding error, we make a calculation of radix- 2 DIT-IFFT. Comparing the result of DIT-IFFT and sampling speech data, error is less than 10-3.

  12. Comparison of Optimized Soft-Tissue Suppression Schemes for Ultra-short Echo Time (UTE) MRI

    PubMed Central

    Li, Cheng; Magland, Jeremy F.; Rad, Hamidreza Saligheh; Song, Hee Kwon; Wehrli, Felix W.

    2011-01-01

    Ultra-short echo time (UTE) imaging with soft-tissue suppression reveals short-T2 components (typically hundreds of microseconds to milliseconds) ordinarily not captured or obscured by long-T2 tissue signals on the order of tens of milliseconds or longer. The technique therefore enables visualization and quantification of short-T2 proton signals such as those in highly collagenated connective tissues. This work compares the performance of the three most commonly used long-T2 suppression UTE sequences, i.e. echo subtraction (dual-echo UTE), saturation via dual-band saturation pulses (dual-band UTE), and inversion by adiabatic inversion pulses (IR-UTE) at 3T, via Bloch simulations and experimentally in vivo in the lower extremities of test subjects. For unbiased performance comparison, the acquisition parameters are optimized individually for each sequence to maximize short-T2 SNR and CNR between short- and long-T2 components. Results show excellent short-T2 contrast is achieved with these optimized sequences. A combination of dual-band UTE with dual-echo UTE provides good short-T2 SNR and CNR with less sensitivity to B1 homogeneity. IR-UTE has the lowest short-T2 SNR efficiency but provides highly uniform short-T2 contrast and is well suited for imaging short-T2 species with relatively short T1 such as bone water. PMID:22161636

  13. Revisiting the time domain induced polarization technique, from linearization to inversion

    NASA Astrophysics Data System (ADS)

    Kang, S.; Oldenburg, D.

    2015-12-01

    The induced polarization (IP) technique has been successful in mineral exploration, particularly for finding disseminated sulphide or porphyry deposits, but also in helping solve geotechnical and environmental problems. Electrical induced polarization (EIP) surveys use grounded electrodes and take measurements of the electric field while the current is both "on" and "off". Currently, 2D and 3D inversions of EIP data are generally carried out by first finding a background conductivity from the asymptotic "on-time" measurements. The DC resistivity problem is then linearized about that conductivity to obtain a linear relationship between the off-time data and the "pseudo-chargeability". The distribution of pseudo-chargeability in the earth is then interpreted within the context of the initial geoscience problem pursued. Despite its success, the current EIP implementation does have challenges. A fundamental assumption, that there is no electromagnetic induction (EM) effect, breaks down when the background is conductive. This is especially problematic in regions having conductive overburden. EM induction complicates, and sometimes overwhelms, the IP signal. To ameliorate this effect, we estimate the inductive signal, subtract it from the "off-time" data and invert the resultant IP data using the linearized formulation. We carefully examine the conditions under which this works. We also investigate the potential alterations to the linearized sensitivity function that are needed to allow a linearized inversion to be carried out. Inversions of EIP data recover a "chargeability" but this is not a uniquely defined quantity. There are multiple definitions of this property because there are a diverse number of ways in which an IP datum is defined. In time domain IP surveys, the data might be mV/V or a time-integrated voltage with units of ms. In reality however, data from an EIP survey have many time channels and each one can be inverted separately to produce a chargeability

  14. Temporal moments revisited: Why there is no better way for physically based model reduction in time

    NASA Astrophysics Data System (ADS)

    Leube, P. C.; Nowak, W.; Schneider, G.

    2012-11-01

    Many hydro(geo)logical problems are highly complex in space and time, coupled with scale issues, variability, and uncertainty. Especially time-dependent models often consume enormous computational resources, but model reduction techniques can alleviate this problem. Temporal moments (TM) offer an approach to reduce the time demands of transient hydro(geo)logical simulations. TM reduce transient governing equations to steady state and directly simulate the temporal characteristics of the system, if the equations are linear and coefficients are time independent. This is achieved by an integral transform, projecting the dynamic system response onto monomials in time. In comparison to classical approaches of model reduction that involve orthogonal base functions, however, the monomials for TM are nonorthogonal, which might impair the quality and efficiency of model reduction. Thus, we raise the question of whether there are more suitable temporal base functions than the monomials that lead to TM. In this work, we will derive theoretically that there is only a limited class of temporal base functions that can reduce hydro(geo)logical models. By comparing those to TM we conclude that, in terms of gained efficiency versus maintained accuracy, TM are the best possible choice. While our theoretical results hold for all systems of linear partial or ordinary differential equations (PDEs, ODEs) with any order of space and time derivatives, we illustrate our study with an example of pumping tests in a confined aquifer. For that case, we demonstrate that two (four) TM are sufficient to represent more than 80% (90%) of the dynamic behavior, and that the information content strictly increases with increasing TM order.

  15. Revisiting Enquiry-Based Teacher Education in Neo-Liberal Times

    ERIC Educational Resources Information Center

    Reid, Alan; O'Donoghue, Michael

    2004-01-01

    In contemporary times educators must be able to work effectively within contexts of change, paradox and instability. This has implications for programs that prepare teachers. In particular, teacher education programs should seek to develop teachers who can enquire systematically and critically into their educational practices. However, current…

  16. Parental Use of Time Out Revisited: A Useful or Harmful Parenting Strategy?

    ERIC Educational Resources Information Center

    Morawska, Alina; Sanders, Matthew

    2011-01-01

    Time out has been widely advocated as an effective parental discipline practice to reduce disruptive and oppositional child behaviour in young children. Despite evidence showing that the procedure is effective when used as part of a comprehensive positive parenting strategy it has not been uniformly accepted and critics have questioned its…

  17. What Time Is Sunrise? Revisiting the Refraction Component of Sunrise/set Prediction Models

    NASA Astrophysics Data System (ADS)

    Wilson, Teresa; Bartlett, Jennifer L.; Hilton, James Lindsay

    2017-01-01

    Algorithms that predict sunrise and sunset times currently have an error of one to four minutes at mid-latitudes (0° - 55° N/S) due to limitations in the atmospheric models they incorporate. At higher latitudes, slight changes in refraction can cause significant discrepancies, even including difficulties determining when the Sun appears to rise or set. While different components of refraction are known, how they affect predictions of sunrise/set has not yet been quantified. A better understanding of the contributions from temperature profile, pressure, humidity, and aerosols could significantly improve the standard prediction. We present a sunrise/set calculator that interchanges the refraction component by varying the refraction model. We then compare these predictions with data sets of observed rise/set times to create a better model. Sunrise/set times and meteorological data from multiple locations will be necessary for a thorough investigation of the problem. While there are a few data sets available, we will also begin collecting this data using smartphones as part of a citizen science project. The mobile application for this project will be available in the Google Play store. Data analysis will lead to more complete models that will provide more accurate rise/set times for the benefit of astronomers, navigators, and outdoorsmen everywhere.

  18. Coronal Shocks of November 1997 Revisited: The CME-Type II Timing Problem

    DTIC Science & Technology

    2004-08-24

    Introduction 20060214 002 Solar metric type II bursts (reviewed by Nelson and Melrose, 1985) drift outward through the low corona from high to low...taken by the Large Angle and Spectrometric Corona - graph’s (LASCO) (Brueckner et al., 1995) C2 and C3 instruments on the Solar and Heliospheric...Delaboudini~re et al., 1995), which observes the solar disk and the corona up to 1.5 R0, to determine CME launch times without any need for

  19. Insights into How Longicorn Beetle Larvae Determine the Timing of Metamorphosis: Starvation-Induced Mechanism Revisited

    PubMed Central

    Nagamine, Keisuke; Ishikawa, Yukio; Hoshizaki, Sugihiko

    2016-01-01

    Larvae of holometabolous insects must determine the timing of their metamorphosis. How they determine this timing has only been studied in detail for a few insect species. In a few species of Coleoptera, starvation is known to be a cue for metamorphosis, leading to the formation of smaller adults (starvation-induced pupation, SiP). We investigated the occurrence of SiP in the beetle Psacothea hilaris. When P. hilaris larvae were starved late in the feeding phase of the last (5th) instar, they exhibited typical SiP characterized by constancy of the time from food deprivation to pupation (TTP) irrespective of the body weight upon food deprivation or the length of prior feeding. In contrast, when larvae were starved early in the feeding phase, TTP decreased by roughly 1 day as the feeding became 1 day longer. The change in the response to starvation was estimated to occur on day 5.9 in the last instar. A series of refeeding experiments suggested that whereas SiP occurred readily in the larvae starved in the late feeding phase, activation of SiP was suspended until day 5.9 in the larvae starved early in the feeding phase. When P. hilaris larvae were fed continuously, they eventually ceased feeding spontaneously and pupated. The time length between spontaneous cessation of feeding and pupation was approximately equal to the TTP in SiP. This suggests that the same mechanism was activated by food deprivation in the late feeding phase and by spontaneous cessation of ad libitum feeding. PMID:27386861

  20. 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…

  1. 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 Schrödinger 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 α line is discussed.

  2. Visual processing of the impending collision of a looming object: time to collision revisited.

    PubMed

    Yan, Jing-Jiang; Lorv, Bailey; Li, Hong; Sun, Hong-Jin

    2011-10-14

    As an object approaches an observer's eye, the optical variable tau, defined as the inverse relative expansion rate of the object's image on the retina (D. N. Lee, 1976), approximates the time to collision (TTC). Many studies have provided support that human observers use TTC, but evidence for the exclusive use of TTC generated by tau remains inconclusive. In the present study, observers were presented with a visual display of two sequentially approaching objects and asked to compare their TTCs at the moment these objects vanished. Upon dissociating several variables that may have potentially contributed to TTC perception, we found that observers were most sensitive to TTC information when completing the task and less sensitive to non-time variables, such as those that specified distance to collision, speed, and object size. Moreover, when we manipulated presented variables to provide conflicting TTC information, TTC specified by tau was weighted much more than TTC derived from distance and speed. In conclusion, our results suggested that even in the presence of other monocular sources of information, observers still had a greater tendency to specifically use optical tau when making relative TTC judgments.

  3. Circinus X-1 revisited: Fast-timing properties in relation to spectral state

    NASA Technical Reports Server (NTRS)

    Oosterbroek, T.; Van Der Klis, M.; Kuulkers, E.; Van Paradijs, J.; Lewin, W. H. G.

    1995-01-01

    We have studied the X-ray spectral and fast-timing variations of Cir X-1 by performing a homogenous analysis of all EXOSAT ME data on this source using X-ray hardness-intensity diagrams (HIDs), color-color diagrams (CDs), and power spectra. Cir X-1 exhibits a wide range of power spectral shapes and a large variety in X-ray spectral shapes. At different epochs the power spectra variously resemble those of an atoll source, a Z source, a black-hole candidate, or are unlike any of these. At some epochs one-dimensional connected-branch patterns are seen in HID and CD, and at other times more complex structures are found. We interpret the complex behavior of Cir X-1 in terms of a model where accretion rate, orbital phase and epoch are the main determinants of the source behavior, and where the unique properties of the source are due to two special circumstances: (1) the source is the only known atoll source (accreting neutron star with a very low magnetic field) that can reach the Eddington critical accretion rate, and (2) it has a unique, highly eccentric and probably precessing orbit. Property (1) makes Cir X-1 a very important source for our understanding of the similarities in the observable properties of neutron stars and black holes as it allows to separate out black hole signatures from properties that are merely due to the presence of accretion compact with a low magnetic field.

  4. NMR measurement and Brownian movement in the short-time limit

    NASA Astrophysics Data System (ADS)

    Stepišnik, Janez

    1994-05-01

    This study is carried out to find relations between the time-dependent molecular self-diffusion and the attenuation of NMR spin-echo. Two cases of diffusion are considered: the Brownian motion in Ornstein's short-time limit and the random walk with memory [13]. The friction and the correlation time describe the mechanism of entrapping interactions between molecules or their bonding to macromolecule chains. The obtained formula for the self-diffusion attenuation is valid at short times and it develops into the well-known Torrey's result in the long-time limit. It fits very efficiently into the NMR data from Refs. [19-20].

  5. Low-temperature electron dephasing time in AuPd revisited

    NASA Astrophysics Data System (ADS)

    Lin, J. J.; Lee, T. C.; Wang, S. W.

    2007-10-01

    Ever since the first discoveries of the quantum-interference transport in mesoscopic systems, the electron dephasing times, τϕ, in the concentrated AuPd alloys have been extensively measured. The samples were made from different sources with different compositions, prepared by different deposition methods, and various geometries (1D narrow wires, 2D thin films, and 3D thick films) were studied. Surprisingly, the low-temperature behavior of τϕ inferred by different groups over two decades reveals a systematic correlation with the level of disorder of the sample. At low temperatures, where τϕ is (nearly) independent of temperature, a scaling τϕmax∝D is found, where τϕmax is the maximum value of τϕ measured in the experiment, D is the electron diffusion constant, and the exponent α is close to or slightly larger than 1. We address this nontrivial scaling behavior and suggest that the most possible origin for this unusual dephasing is due to dynamical structure defects, while other theoretical explanations may not be totally ruled out.

  6. The effects of time, luminance, and high contrast targets: revisiting grating acuity in the domestic cat.

    PubMed

    Clark, Daria L; Clark, Robert A

    2013-11-01

    Based on optical clarity and retinal cone density, the cat has a potential acuity of 20-30 cycles per degree (cpd), yet most behavioral studies estimate feline acuity between 3 and 9 cpd. Those studies, however, were limited by restrictive experimental conditions that may have inadvertently lowered the estimated grating acuity. Two domestic cats previously trained on a two-choice visual discrimination task were retrained on a grating detection/discrimination task with unlimited time, high luminance, high contrast targets, and adequate space to prevent poor accommodation from affecting the results. Initially, vertical gratings of increasing cpd were tested until failure. Then, horizontal gratings of increasing cpd were tested until failure. Finally, the finest horizontal grating resolved was confirmed with a third test requiring 24 correct out of 36 consecutive trials, yielding a binomial probability less than 0.02 of non-random occurrence. M1, a 7-year-old male gray tabby with +2.00 OU refraction, tested for a grating detection acuity of 15 cpd for both vertical and horizontal gratings (binomial probability = 0.009). F1, a 2-year-old female gray tabby with +0.25 OU refraction, tested for a grating orientation discrimination acuity of 20 cpd for both vertical and horizontal gratings (binomial probability = 0.004). These results demonstrate that a young cat with good focus is capable of discriminating 20 cpd, in close agreement with the physiologic maximum. Uncorrected focusing errors appear to degrade visual performance. Optimum experimental conditions resulted in better grating acuity measurements than previously reported, emphasizing the importance of environmental factors in feline behavioral testing.

  7. 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.

  8. Temporal Prediction Errors Affect Short-Term Memory Scanning Response Time.

    PubMed

    Limongi, Roberto; Silva, Angélica M

    2016-11-01

    The Sternberg short-term memory scanning task has been used to unveil cognitive operations involved in time perception. Participants produce time intervals during the task, and the researcher explores how task performance affects interval production - where time estimation error is the dependent variable of interest. The perspective of predictive behavior regards time estimation error as a temporal prediction error (PE), an independent variable that controls cognition, behavior, and learning. Based on this perspective, we investigated whether temporal PEs affect short-term memory scanning. Participants performed temporal predictions while they maintained information in memory. Model inference revealed that PEs affected memory scanning response time independently of the memory-set size effect. We discuss the results within the context of formal and mechanistic models of short-term memory scanning and predictive coding, a Bayes-based theory of brain function. We state the hypothesis that our finding could be associated with weak frontostriatal connections and weak striatal activity.

  9. Integrating random matrix theory predictions with short-time dynamical effects in chaotic systems.

    PubMed

    Smith, A Matthew; Kaplan, Lev

    2010-07-01

    We discuss a modification to random matrix theory eigenstate statistics that systematically takes into account the nonuniversal short-time behavior of chaotic systems. The method avoids diagonalization of the Hamiltonian; instead it requires only 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.

  10. Short term frequency stability measurement for narrow linewidth laser by time domain self-heterodyne method

    NASA Astrophysics Data System (ADS)

    Lu, Lidong; Sun, Xiaoyan; Bu, Xiande; Li, Binglin

    2016-11-01

    Based on the time delay self-heterodyne method to measure the laser linewidth, the short-term linewidth variation of a narrow linewidth laser is experimentally studied and analyzed, and then a time domain self-heterodyne method is proposed to measure the short-term frequency stability of narrow linewidth laser. The Rayleigh backscattering frequency of a pulsed light propagating in an optical fiber with length of 100km is used as the local oscillation frequency with relatively long time duration to measure the frequency variation of the narrow linewidth laser. By heterodyne between the laser frequency and the local oscillation frequency, the variation of the laser frequency is presented in the heterodyne radio frequency (IF). Then the time domain data of the heterodyne IF are extracted by an oscilloscope and through short time Fourier transform the frequency from the laser in different time segments is obtained. Experimental results demonstrate that for narrow linewidth laser its frequency in short-term is randomly fluctuating with a range less than triple of the laser linewidth. The measurement and evaluation of laser short-term frequency stability benefits the application of narrow linewidth lasers in distributed optical fiber sensing area.

  11. Psychometric properties of the Hebrew short version of the Zimbardo Time Perspective Inventory.

    PubMed

    Orkibi, Hod

    2015-06-01

    The purpose of this study was to develop a short Hebrew version of the Zimbardo Time Perspective Inventory that can be easily administered by health professionals in research, therapy, and counseling. First, the empirical links of time perspective (TP) to subjective well-being and health protective and health risk behaviors are reviewed. Then, a brief account of the instrument's previous modifications is provided. Results of confirmatory factor analysis (N = 572) verified the five-factor structure of the short version and yielded acceptable internal consistency reliability for each factor. The correlation coefficients between the five subscales of the short (20 items) and the original (56 items) instruments were all above .79, indicating the suitability of the short version for assessing the five TP factors. Support for the discriminant and concurrent validity was also achieved, largely in agreement with previous findings. Finally, limitations and future directions are addressed, and potential applications in therapy and counseling are offered.

  12. Real-time mobile customer short message system design and implementation

    NASA Astrophysics Data System (ADS)

    Han, Qirui; Sun, Fang

    To expand the current mobile phone short message service, and to make the contact between schools, teachers, parents and feedback of the modern school office system more timely and conveniently, designed and developed the Short Message System based on the Linux platform. The state-of-the-art principles and designed proposals in the Short Message System based on the Linux platform are introduced. Finally we propose an optimized secure access authentication method. At present, many schools,vbusinesses and research institutions ratify the promotion and application the messaging system gradually, which has shown benign market prospects.

  13. Intelligence Revisited

    DTIC Science & Technology

    2005-05-01

    reasoning, rote memory , and the like.” Standardized tests also fall short in terms of assessing other important aspects of intelligence such as creativity...ipEngine made by BrightStar Engineering. Then in 2004 we further evolved to a Compulab 686 CORE with 128 megabytes of memory running at 266 mHz...driver runs in a continuous loop, timing sonar echoes on each pass, storing the resulting range values in memory for on-demand access by other

  14. 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.

  15. Viruses as groundwater tracers: using ecohydrology to characterize short travel times in aquifers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Viruses are attractive tracers of short (<3 yr) travel times in aquifers because they have unique genetic signatures, are detectable in trace quantities, and are mobile and stable in groundwater. Virus “snaphots” result from infection and disappearance over time as a community develops resistance. T...

  16. Detecting Causality from Nonlinear Dynamics with Short-term Time Series

    NASA Astrophysics Data System (ADS)

    Ma, Huanfei; Aihara, Kazuyuki; Chen, Luonan

    2014-12-01

    Quantifying causality between variables from observed time series data is of great importance in various disciplines but also a challenging task, especially when the observed data are short. Unlike the conventional methods, we find it possible to detect causality only with very short time series data, based on embedding theory of an attractor for nonlinear dynamics. Specifically, we first show that measuring the smoothness of a cross map between two observed variables can be used to detect a causal relation. Then, we provide a very effective algorithm to computationally evaluate the smoothness of the cross map, or ``Cross Map Smoothness'' (CMS), and thus to infer the causality, which can achieve high accuracy even with very short time series data. Analysis of both mathematical models from various benchmarks and real data from biological systems validates our method.

  17. Improvement in the Mechanical Behavior of Mechanically Alloyed Aluminum Using Short-Time NH3 Flow

    NASA Astrophysics Data System (ADS)

    Caballero, E. S.; Cintas, J.; Cuevas, F. G.; Montes, J. M.; Herrera-García, M.

    2016-12-01

    In order to study the influence of a short-time ammonia gas flow during mechanical alloying (MA) of aluminum powders, samples were prepared using a simple press and sinter method. All milling experiments were performed at room temperature for a total of 10 hours. A short-time ammonia flow was incorporated into the milling process, allowing for the appearance of nitrogen-rich second phases, mainly oxycarbonitride and oxynitride aluminum (Al3CON and Al5O6N, respectively), during powder sintering. Testing of the sintering parts showed that the use of a short-time ammonia gas flow during vacuum milling substantially improved the mechanical properties at room and high temperatures.

  18. Detecting Causality from Nonlinear Dynamics with Short-term Time Series

    PubMed Central

    Ma, Huanfei; Aihara, Kazuyuki; Chen, Luonan

    2014-01-01

    Quantifying causality between variables from observed time series data is of great importance in various disciplines but also a challenging task, especially when the observed data are short. Unlike the conventional methods, we find it possible to detect causality only with very short time series data, based on embedding theory of an attractor for nonlinear dynamics. Specifically, we first show that measuring the smoothness of a cross map between two observed variables can be used to detect a causal relation. Then, we provide a very effective algorithm to computationally evaluate the smoothness of the cross map, or “Cross Map Smoothness” (CMS), and thus to infer the causality, which can achieve high accuracy even with very short time series data. Analysis of both mathematical models from various benchmarks and real data from biological systems validates our method. PMID:25501646

  19. Detecting causality from nonlinear dynamics with short-term time series.

    PubMed

    Ma, Huanfei; Aihara, Kazuyuki; Chen, Luonan

    2014-12-12

    Quantifying causality between variables from observed time series data is of great importance in various disciplines but also a challenging task, especially when the observed data are short. Unlike the conventional methods, we find it possible to detect causality only with very short time series data, based on embedding theory of an attractor for nonlinear dynamics. Specifically, we first show that measuring the smoothness of a cross map between two observed variables can be used to detect a causal relation. Then, we provide a very effective algorithm to computationally evaluate the smoothness of the cross map, or "Cross Map Smoothness" (CMS), and thus to infer the causality, which can achieve high accuracy even with very short time series data. Analysis of both mathematical models from various benchmarks and real data from biological systems validates our method.

  20. 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 Cα trajectories from two independent molecular-dynamics simulations of α-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

  1. Relationship between short activated partial thromboplastin times, thrombin generation, procoagulant factors and procoagulant phospholipid activity.

    PubMed

    Mina, Ashraf; Favaloro, Emmanuel J; Koutts, Jerry

    2012-04-01

    Short activated partial thromboplastin times (APTTs) are associated with thrombosis. However, what short APTTs actually represent in terms of possible mechanistic pathways is not well characterized. We have assessed thrombin generation as compared with levels of procoagulant factor (fibrinogen, V, VIII, IX, XI and XII) activities, von Willebrand factor level and activity using collagen binding, as well as procoagulant phospholipid activity, in 113 consecutive samples exhibiting a short APTT compared with an equal number of age-matched and sex-matched samples yielding a normal APTT. We found a significant difference in peak thrombin generation, velocity index and area under the curve between the two groups, and that thrombin generation markers correlated with the APTT, procoagulant phospholipid activity and several procoagulant clotting factors. We conclude that short APTTs represent a procoagulant milieu, as represented by heightened thrombin generation and several other heightened procoagulant activities, which may help explain the association with thrombosis.

  2. Viruses as groundwater tracers: using ecohydrology to characterize short travel times in aquifers.

    PubMed

    Hunt, Randall J; Borchardt, Mark A; Bradbury, Kenneth R

    2014-01-01

    Viruses are attractive tracers of short (<3 year) travel times in aquifers because they have unique genetic signatures, are detectable in trace quantities, and are mobile in groundwater. Virus "snaphots" result from infection and disappearance in a population over time; therefore, the virus snapshot shed in the fecal wastes of an infected population at a specific point in time can serve as a marker for tracking virus and groundwater movement. The virus tracing approach and an example application are described to illustrate their ability to characterize travel times in high-groundwater velocity settings, and provide insight unavailable from standard hydrogeologic approaches. Although characterization of preferential flowpaths does not usually characterize the majority of other travel times occurring in the groundwater system (e.g., center of plume mass; tail of the breakthrough curve), virus approaches can trace very short times of transport, and thus can fill an important gap in our current hydrogeology toolbox.

  3. Viruses as groundwater tracers: using ecohydrology to characterize short travel times in aquifers

    USGS Publications Warehouse

    Hunt, Randall J.; Borchardt, Mark A.; Bradbury, Kenneth R.

    2014-01-01

    Viruses are attractive tracers of short (<3 year) travel times in aquifers because they have unique genetic signatures, are detectable in trace quantities, and are mobile in groundwater. Virus “snaphots” result from infection and disappearance in a population over time; therefore, the virus snapshot shed in the fecal wastes of an infected population at a specific point in time can serve as a marker for tracking virus and groundwater movement. The virus tracing approach and an example application are described to illustrate their ability to characterize travel times in high-groundwater velocity settings, and provide insight unavailable from standard hydrogeologic approaches. Although characterization of preferential flowpaths does not usually characterize the majority of other travel times occurring in the groundwater system (e.g., center of plume mass; tail of the breakthrough curve), virus approaches can trace very short times of transport, and thus can fill an important gap in our current hydrogeology toolbox.

  4. Universal short-time dynamics: Boundary functional renormalization group for a temperature quench

    NASA Astrophysics Data System (ADS)

    Chiocchetta, Alessio; Gambassi, Andrea; Diehl, Sebastian; Marino, Jamir

    2016-11-01

    We present a method to calculate short-time nonequilibrium universal exponents within the functional-renormalization-group scheme. As an example, we consider the classical critical dynamics of the relaxational model A after a quench of the temperature of the system and calculate the initial-slip exponent which characterizes the nonequilibrium universal short-time behavior of both the order parameter and correlation functions. The value of this exponent is found to be consistent with the result of a perturbative dimensional expansion and of Monte Carlo simulations in three spatial dimensions.

  5. Dispersion curves from short-time molecular dynamics simulation. 1. Diatomic chain results

    SciTech Connect

    Noid, D.W.; Broocks, B.T.; Gray, S.K.; Marple, S.L.

    1988-06-16

    The multiple signal classification method (MUSIC) for frequency estimation is used to compute the frequency dispersion curves of a diatomic chain from the time-dependent structure factor. In this paper, the authors demonstrate that MUSIC can accurately determine the frequencies from very short time trajectories. MUSIC is also used to show how the frequencies can vary in time, i.e., along a trajectory. The method is ideally suited for analyzing molecular dynamics simulations of large systems.

  6. Short-Time Glassy-like Dynamics Observed in Viscous Protein Solutions with Competing Potential Features

    NASA Astrophysics Data System (ADS)

    Wagner, Norman; Godfrin, Doug; Liu, Yun

    Structures in concentrated protein solutions caused by the combination of short-range attraction (SA) and long-range repulsion (LR) have been extensively studied due to their importance in understanding therapeutic protein formulations and the phase behavior in general. Despite extensive studies of kinetically arrested states in colloidal systems with short-range attraction, less is understood for the effect of an additional longer-range repulsion on model colloidal systems with a SA interaction. Highly purified lysozyme is used a model experimental system due to its stable globular structure and SALR interactions at low ionic strength that can be quantitatively modeled. The fluid microstructure and protein short time self diffusion are measured across a broad range of conditions by small angle neutron scattering (SANS) and neutron spin echo (NSE), respectively. Newtonian liquid behavior is observed at all concentrations, even with an increase of zero shear viscosity by almost four orders of magnitude with increasing concentration. However, dynamic measurements demonstrate a sub-diffusive regime at relatively short time scales for concentrated samples at low temperature. The formation of a heterogeneous density distribution is shown to produce localized regions of high density that reduce protein motion, giving it a glassy-like behavior at the short time scale. This heterogeneity occurs at the length scale associated with the intermediate range order driven by the competing potential features, distinguishable from heterogeneous colloidal gels.

  7. Short relaxation times but long transient times in both simple and complex reaction networks

    PubMed Central

    Henry, Adrien; Martin, Olivier C.

    2016-01-01

    When relaxation towards an equilibrium or steady state is exponential at large times, one usually considers that the associated relaxation time τ, i.e. the inverse of the decay rate, is the longest characteristic time in the system. However, that need not be true, other times such as the lifetime of an infinitesimal perturbation can be much longer. In the present work, we demonstrate that this paradoxical property can arise even in quite simple systems such as a linear chain of reactions obeying mass action (MA) kinetics. By mathematical analysis of simple reaction networks, we pin-point the reason why the standard relaxation time does not provide relevant information on the potentially long transient times of typical infinitesimal perturbations. Overall, we consider four characteristic times and study their behaviour in both simple linear chains and in more complex reaction networks taken from the publicly available database ‘Biomodels’. In all these systems, whether involving MA rates, Michaelis–Menten reversible kinetics, or phenomenological laws for reaction rates, we find that the characteristic times corresponding to lifetimes of tracers and of concentration perturbations can be significantly longer than τ. PMID:27411726

  8. 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.

  9. Managing the Editing Function on Large Publication Tasks with Short Flow Times.

    ERIC Educational Resources Information Center

    Santa, Terry M. Dalla

    Large publication tasks with short flow times require that several editors be assigned to work together as part of a larger publication team that includes management, engineer-writers, publishing logistics personnel, word processor operators, illustrators, and printers. Team-edited publications have special problems, and the technical editing and…

  10. Neural network incorporating meal information improves accuracy of short-time prediction of glucose concentration.

    PubMed

    Zecchin, Chiara; Facchinetti, Andrea; Sparacino, Giovanni; De Nicolao, Giuseppe; Cobelli, Claudio

    2012-06-01

    Diabetes mellitus is one of the most common chronic diseases, and a clinically important task in its management is the prevention of hypo/hyperglycemic events. This can be achieved by exploiting continuous glucose monitoring (CGM) devices and suitable short-term prediction algorithms able to infer future glycemia in real time. In the literature, several methods for short-time glucose prediction have been proposed, most of which do not exploit information on meals, and use past CGM readings only. In this paper, we propose an algorithm for short-time glucose prediction using past CGM sensor readings and information on carbohydrate intake. The predictor combines a neural network (NN) model and a first-order polynomial extrapolation algorithm, used in parallel to describe, respectively, the nonlinear and the linear components of glucose dynamics. Information on the glucose rate of appearance after a meal is described by a previously published physiological model. The method is assessed on 20 simulated datasets and on 9 real Abbott FreeStyle Navigator datasets, and its performance is successfully compared with that of a recently proposed NN glucose predictor. Results suggest that exploiting meal information improves the accuracy of short-time glucose prediction.

  11. APPARATUS FOR SHORT TIME MEASUREMENTS IN A FIXED-BED, GAS/SOLID REACTOR

    EPA Science Inventory

    An apparatus for exposure of a solid to reactive process gas is described which makes possible short time (≥ 0.3 to 15 s) exposures in a fixed-bed reactor. Operating conditions for differential reaction with respect to the gas concentration and rapid quench for arresting hi...

  12. 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…

  13. 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...

  14. Dissociation of Short-Term Forgetting from the Passage of Time

    ERIC Educational Resources Information Center

    White, K. Geoffrey

    2012-01-01

    In many theories, forgetting is closely linked to the passage of time. In the present experiments, recall in a short-term memory task was less accurate when the retention interval included a difficult arithmetic addition task, compared with an easy task. In a novel condition, the interfering task was switched from hard to easy partway through the…

  15. Dynamical complexity of short and noisy time series - Compression-Complexity vs. Shannon entropy

    NASA Astrophysics Data System (ADS)

    Nagaraj, Nithin; Balasubramanian, Karthi

    2017-01-01

    Shannon entropy has been extensively used for characterizing complexity of time series arising from chaotic dynamical systems and stochastic processes such as Markov chains. However, for short and noisy time series, Shannon entropy performs poorly. Complexity measures which are based on lossless compression algorithms are a good substitute in such scenarios. We evaluate the performance of two such Compression-Complexity Measures namely Lempel-Ziv complexity (LZ) and Effort-To-Compress (ETC) on short time series from chaotic dynamical systems in the presence of noise. Both LZ and ETC outperform Shannon entropy (H) in accurately characterizing the dynamical complexity of such systems. For very short binary sequences (which arise in neuroscience applications), ETC has higher number of distinct complexity values than LZ and H, thus enabling a finer resolution. For two-state ergodic Markov chains, we empirically show that ETC converges to a steady state value faster than LZ. Compression-Complexity measures are promising for applications which involve short and noisy time series.

  16. Short-time dynamics of monomers and dimers in quasi-two-dimensional colloidal mixtures.

    PubMed

    Sarmiento-Gómez, Erick; Villanueva-Valencia, José Ramón; Herrera-Velarde, Salvador; Ruiz-Santoyo, José Arturo; Santana-Solano, Jesús; Arauz-Lara, José Luis; Castañeda-Priego, Ramón

    2016-07-01

    We report on the short-time dynamics in colloidal mixtures made up of monomers and dimers highly confined between two glass plates. At low concentrations, the experimental measurements of colloidal motion agree well with the solution of the Navier-Stokes equation at low Reynolds numbers; the latter takes into account the increase in the drag force on a colloidal particle due to wall-particle hydrodynamic forces. More importantly, we find that the ratio of the short-time diffusion coefficient of the monomer and that of the center of mass of the dimmer is almost independent of both the dimer molar fraction, x_{d}, and the total packing fraction, ϕ, up to ϕ≈0.5. At higher concentrations, this ratio displays a small but systematic increase. A similar physical scenario is observed for the ratio between the parallel and the perpendicular components of the short-time diffusion coefficients of the dimer. This dynamical behavior is corroborated by means of molecular dynamics computer simulations that include explicitly the particle-particle hydrodynamic forces induced by the solvent. Our results suggest that the effects of colloid-colloid hydrodynamic interactions on the short-time diffusion coefficients are almost identical and factorable in both species.

  17. A Unified Framework for Estimating Minimum Detectable Effects for Comparative Short Interrupted Time Series Designs

    ERIC Educational Resources Information Center

    Price, Cristofer; Unlu, Fatih

    2014-01-01

    The Comparative Short Interrupted Time Series (C-SITS) design is a frequently employed quasi-experimental method, in which the pre- and post-intervention changes observed in the outcome levels of a treatment group is compared with those of a comparison group where the difference between the former and the latter is attributed to the treatment. The…

  18. An Overview on Short and Long Time Relaxations in Glass-forming Supercooled Liquids

    NASA Astrophysics Data System (ADS)

    Karmakar, Smarajit

    2016-10-01

    Density fluctuations in supercooled liquids near the glass transition relax in multiple steps. The short time relaxation is known as β-relaxation and the final long time relaxation is called α-relaxation. It is believed that the long time α-relaxation is a cooperative phenomena associated with a growing length scales, whereas the short-time β-relaxation is often attributed to spatially local processes involving the rattling motion of a particle in the transient cage formed by its neighbors. Using molecular dynamics simulations of few model glass-forming liquids, we show that the β-relaxation is also cooperative in nature and the length scale extracted from the detailed finite-size scaling analysis of β-relaxation is found to be the same as that of the length scale that describes the spatial heterogeneity of local dynamics in the long-time α-relaxation regime. These results provide a clear connection between short-time dynamics and long-time structural relaxation in glass-forming liquids.

  19. Communication: An exact short-time solver for the time-dependent Schrödinger equation

    PubMed Central

    Sun, Zhigang; Yang, Weitao

    2011-01-01

    The short-time integrator for propagating the time-dependent Schrödinger equation, which is exact to machine’s round off accuracy when the Hamiltonian of the system is time-independent, was applied to solve dynamics processes. This integrator has the old Cayley’s form [i.e., the Padé (1,1) approximation], but is implemented in a spectrally transformed Hamiltonian which was first introduced by Chen and Guo. Two examples are presented for illustration, including calculations of the collision energy-dependent probability passing over a barrier, and interaction process between pulse laser and the I2 diatomic molecule. PMID:21280676

  20. Removals of pharmaceutical compounds from hospital wastewater in membrane bioreactor operated under short hydraulic retention time.

    PubMed

    Prasertkulsak, S; Chiemchaisri, C; Chiemchaisri, W; Itonaga, T; Yamamoto, K

    2016-05-01

    Pilot-scale membrane bioreactor (MBR) was operated at a short hydraulic retention time (HRT) of 3 h for the treatment of hospital wastewater. The removals of eleven pharmaceutical compounds in MBR operated at different mixed liquor suspended solids (MLSS) level were investigated during which nitrification degree was differed. The results experiments revealed the importance of immediate adsorption onto the colloidal particles in supernatant of MBR sludge and subsequently removed by membrane filtration for the recalcitrant pharmaceutical compounds. Nevertheless, the removals through biodegradation during short HRT were also found significant for some compounds. DGGE profile revealed the development of pharmaceutical degrading microorganisms in MBR.

  1. A short-time fading study of Al2O3:C

    NASA Astrophysics Data System (ADS)

    Nascimento, L. F.; Vanhavere, F.; Silva, E. H.; Deene, Y. De

    2015-01-01

    This paper studies the short-time fading from Al2O3:C by measuring optically stimulated luminescence (OSL) signals (Total OSL: TOSL, and Peak OSL: POSL) from droplets and Luxel™ pellets. The influence of various bleaching regimes (blue, green and white) and light power is compared. The fading effect is the decay of the OSL signal in the dark at room temperature. Al2O3:C detectors were submitted to various bleaching regimes, irradiated with a reference dose and read out after different time spans. Investigations were carried out using 2 mm size droplet detectors, made of thin Al2O3:C powder mixed with a photocured polymer. Tests were compared to Luxel™-type detectors (Landauer Inc.). Short-time post-irradiation fading is present in OSL results (TOSL and POSL) droplets for time spans up to 200 s. The effect of short-time fading can be lowered/removed when treating the detectors with high-power and/or long time bleaching regimes; this result was observed in both TOSL and POSL from droplets and Luxel™.

  2. Detection systems for short-time stroboscopic neutron imaging and measurements on a rotating engine

    NASA Astrophysics Data System (ADS)

    Schillinger, B.; Abele, H.; Brunner, J.; Frei, G.; Gähler, R.; Gildemeister, A.; Hillenbach, A.; Lehmann, E.; Vontobel, P.

    2005-04-01

    Today's neutron sources do not deliver sufficient flux to examine singular short-time events in the millisecond range by neutron radiography. However, periodic processes can be examined if a triggered accumulating detector collects information of identical time-windows and positions over several cycles of the process. The same problem applies if the source signal itself carries information, like the energy-time dependence in the pulse of a spallation source. Several possible detection methods were considered; measurements were performed at the intense neutron beam H9 of ILL Grenoble, where an electrically driven BMW engine was examined at 1000 rpm with time resolution of 200 μs.

  3. Corrections for the combined effects of decay and dead time in live-timed counting of short-lived radionuclides.

    PubMed

    Fitzgerald, R

    2016-03-01

    Studies and calibrations of short-lived radionuclides, for example (15)O, are of particular interest in nuclear medicine. Yet counting experiments on such species are vulnerable to an error due to the combined effect of decay and dead time. Separate decay corrections and dead-time corrections do not account for this issue. Usually counting data are decay-corrected to the start time of the count period, or else instead of correcting the count rate, the mid-time of the measurement is used as the reference time. Correction factors are derived for both those methods, considering both extending and non-extending dead time. Series approximations are derived here and the accuracy of those approximations are discussed.

  4. Effect of short-time external short circuiting on the capacity fading mechanism during long-term cycling of LiCoO2/mesocarbon microbeads battery

    NASA Astrophysics Data System (ADS)

    Zhang, Lingling; Cheng, Xinqun; Ma, Yulin; Guan, Ting; Sun, Shun; Cui, Yingzhi; Du, Chunyu; Zuo, Pengjian; Gao, Yunzhi; Yin, Geping

    2016-06-01

    Commercial LiCoO2/mesocarbon microbeads (MCMB) batteries (CP475148AR) are short circuited by different contact resistances (0.6 mΩ and 5.0 mΩ) for short times. The short circuited battery is cycled for 1000 times, and the effect of the short-time external short circuiting on the capacity fading mechanism during long-term cycling of LiCoO2/MCMB battery is studied by analyzing the morphology, structure, and electrochemical performance. The results of SEM indicates that the morphology of LiCoO2 material is almost unchanged, except that the particle surface becomes smooth, and the solid electrolyte interphase (SEI) film on the surface of MCMB electrode becomes nonuniform due to the high temperature caused by short circuiting. The lithium ions are more difficult to de-intercalate from the anode and the lattice structure of LiCoO2 degrades according to the results of X-ray diffraction (XRD). The high discharge current caused by short circuiting can damage electrodes, leaving vacancies in structure. The damage of electrode structure can lead to a decrease of diffusion coefficient of lithium (D), so polarization increases and mainly caused by the LiCoO2 electrode. The capacity deterioration of short circuited battery during long-term cycling is mainly caused by the increase of polarization and capacity loss of electrodes.

  5. 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.

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

    PubMed

    Tüysüz, Beyhan; Gazioğlu, Nurperi; Ungür, Savaş; Aji, Dolly Yafet; Türkmen, Seval

    2009-01-01

    A 1-month-old boy with shortness of extremities on prenatal US was referred to our department with a provisional diagnosis of achondroplasia. His height was normal but he had short extremities and platyspondyly, premature carpal epiphyses on both hands, and short tubular bones with irregular metaphyses on radiographs. Re-evaluation of the patient at the age of 1 year revealed very short height and premature calcification of the costal cartilages and epiphyses. Spondylometaepiphyseal dysplasia (SMED), short limb-abnormal calcification type was diagnosed. This condition is a very rare autosomal recessively inherited disorder, and most of the patients die in early childhood due to neurological involvement. At the age of 2 years and 5 months, a CT scan showed narrowing of the cervical spinal canal. One month later he died suddenly because of spinal cord injury. In conclusion early diagnosis is very important because the recurrence risk is high and patients may die due to early neurological complications. The time of onset of abnormal calcifications, a diagnostic finding of the disease, is at the age of around 1 year in most patients. When abnormal calcifications are not yet present, but radiological changes associated with SMED are present, this rare disease must be considered.

  7. Short time properties, dynamic fragility and pressure effects in deeply supercooled polymer melts

    NASA Astrophysics Data System (ADS)

    Saltzman, Erica J.; Schweizer, Kenneth S.

    2007-05-01

    Our activated barrier hopping theory of segmental relaxation in deeply supercooled polymer melts is applied to compute short time properties including the glassy shear modulus, localization length and vibrational frequency. Numerical calculations for specific polymers suggest the theory simultaneously predicts a reasonable elastic modulus, localized state vibrational frequency, dynamic fragility and dynamic crossover and glass transition temperatures. The theory also provides explicit connections between short time-/length-scale properties and the slow alpha relaxation process. The extension of the theory to elevated pressures is initiated. Pressure is found to broaden the deeply supercooled regime and reduce the dynamic fragility. However, the predicted Rossler-Sokolov universal supra-Arrhenius law for the temperature dependence of the alpha relaxation time remains accurate at all pressures. A common theme is the essential role played by the ratio of the dynamic crossover temperature (ideal mode coupling critical temperature) and kinetic glass transition temperature even in the deeply supercooled regime where activated processes are dominant.

  8. Fractal analysis of the short time series in a visibility graph method

    NASA Astrophysics Data System (ADS)

    Li, Ruixue; Wang, Jiang; Yu, Haitao; Deng, Bin; Wei, Xile; Chen, Yingyuan

    2016-05-01

    The aim of this study is to evaluate the performance of the visibility graph (VG) method on short fractal time series. In this paper, the time series of Fractional Brownian motions (fBm), characterized by different Hurst exponent H, are simulated and then mapped into a scale-free visibility graph, of which the degree distributions show the power-law form. The maximum likelihood estimation (MLE) is applied to estimate power-law indexes of degree distribution, and in this progress, the Kolmogorov-Smirnov (KS) statistic is used to test the performance of estimation of power-law index, aiming to avoid the influence of droop head and heavy tail in degree distribution. As a result, we find that the MLE gives an optimal estimation of power-law index when KS statistic reaches its first local minimum. Based on the results from KS statistic, the relationship between the power-law index and the Hurst exponent is reexamined and then amended to meet short time series. Thus, a method combining VG, MLE and KS statistics is proposed to estimate Hurst exponents from short time series. Lastly, this paper also offers an exemplification to verify the effectiveness of the combined method. In addition, the corresponding results show that the VG can provide a reliable estimation of Hurst exponents.

  9. Error correction in short time steps during the application of quantum gates

    SciTech Connect

    Castro, L.A. de Napolitano, R.D.J.

    2016-04-15

    We propose a modification of the standard quantum error-correction method to enable the correction of errors that occur due to the interaction with a noisy environment during quantum gates without modifying the codification used for memory qubits. Using a perturbation treatment of the noise that allows us to separate it from the ideal evolution of the quantum gate, we demonstrate that in certain cases it is necessary to divide the logical operation in short time steps intercalated by correction procedures. A prescription of how these gates can be constructed is provided, as well as a proof that, even for the cases when the division of the quantum gate in short time steps is not necessary, this method may be advantageous for reducing the total duration of the computation.

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

    PubMed

    Giese, Kai; Kuhn, 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.

  11. Least squares support vector machine for short-term prediction of meteorological time series

    NASA Astrophysics Data System (ADS)

    Mellit, A.; Pavan, A. Massi; Benghanem, M.

    2013-01-01

    The prediction of meteorological time series plays very important role in several fields. In this paper, an application of least squares support vector machine (LS-SVM) for short-term prediction of meteorological time series (e.g. solar irradiation, air temperature, relative humidity, wind speed, wind direction and pressure) is presented. In order to check the generalization capability of the LS-SVM approach, a K-fold cross-validation and Kolmogorov-Smirnov test have been carried out. A comparison between LS-SVM and different artificial neural network (ANN) architectures (recurrent neural network, multi-layered perceptron, radial basis function and probabilistic neural network) is presented and discussed. The comparison showed that the LS-SVM produced significantly better results than ANN architectures. It also indicates that LS-SVM provides promising results for short-term prediction of meteorological data.

  12. Short-time movement of E. coli chromosomal loci depends on coordinate and subcellular localization.

    PubMed

    Javer, Avelino; Long, Zhicheng; Nugent, Eileen; Grisi, Marco; Siriwatwetchakul, Kamin; Dorfman, Kevin D; Cicuta, Pietro; Cosentino Lagomarsino, Marco

    2013-01-01

    In bacteria, chromosomal architecture shows strong spatial and temporal organization, and regulates key cellular functions, such as transcription. Tracking the motion of chromosomal loci at short timescales provides information related to both the physical state of the nucleo-protein complex and its local environment, independent of large-scale motions related to genome segregation. Here we investigate the short-time (0.1-10 s) dynamics of fluorescently labelled chromosomal loci in Escherichia coli at different growth rates. At these timescales, we observe for the first time a dependence of the loci's apparent diffusion on both their subcellular localization and chromosomal coordinate, and we provide evidence that the properties of the chromosome are similar in the tested growth conditions. Our results indicate that either non-equilibrium fluctuations due to enzyme activity or the organization of the genome as a polymer-protein complex vary as a function of the distance from the origin of replication.

  13. Short-time Lyapunov exponent analysis and the transition to chaos in Taylor-Couette flow

    NASA Technical Reports Server (NTRS)

    Vastano, John A.; Moser, Robert D.

    1991-01-01

    The physical mechanism driving the weakly chaotic Taylor-Couette flow is investigated using the short-time Liapunov exponent analysis. In this procedure, the transition from quasi-periodicity to chaos is studied using direct numerical 3D simulations of axially periodic Taylor-Couette flow, and a partial Liapunov exponent spectrum for the flow is computed by simultaneously advancing the full solution and a set of perturbations. It is shown that the short-time Liapunov exponent analysis yields more information on the exponents and dimension than that obtained from the common Liapunov exponent calculations. Results show that the chaotic state studied here is caused by a Kelvin-Helmholtz-type instability of the outflow boundary jet of Taylor vortices.

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

    PubMed

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

    2013-07-09

    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.

  15. 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

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

    2000-03-01

    FGA, 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.

  16. Revisiting Fitts and Peterson (1964): width and amplitude manipulations to the reaching environment elicit dissociable movement times.

    PubMed

    Heath, Matthew; Weiler, Jeffrey; Marriott, Kendal A; Elliott, Digby; Binsted, Gordon

    2011-12-01

    The classic theorem of Fitts (1954) asserts that the combined effects of movement amplitude and target width (index of difficulty: ID) define movement times (MTs) for goal-directed reaches. Moreover, Fitts' theorem states that reaches yielding the same ID produce equivalent MTs regardless of the response's amplitude and width combination. However, most work providing direct support for Fitts' theorem has employed short movement amplitudes and small target widths. Thus, no direct evidence supports the unitary nature of MT/ID relations across a range of amplitudes and widths used in contemporary studies of goal-directed reaching. To that end, we contrasted MT/ID relations for discrete reaches equated for movement ID but differing with respect to their amplitude (15.5, 19, 25.5, and 38 cm) and width (2, 3, 4, and 5 cm) requirements. Results show that amplitude and width manipulations yielded robust linear MT/ID relations; however, the slope of the MT/ID function was markedly steeper in the former (amplitude=92 ms; width=13 ms). Such findings indicate that the constituent elements of movement ID are dissociable and that the fixed parameter nature of Fitts' theorem cannot be applied to a continuous range of veridical movement amplitudes and target widths.

  17. Using the ENF Criterion for Determining the Time of Recording of Short Digital Audio Recordings

    NASA Astrophysics Data System (ADS)

    Huijbregtse, Maarten; Geradts, Zeno

    The Electric Network Frequency (ENF) Criterion is a recently developed forensic technique for determining the time of recording of digital audio recordings, by matching the ENF pattern from a questioned recording with an ENF pattern database. In this paper we discuss its inherent limitations in the case of short - i.e., less than 10 minutes in duration - digital audio recordings. We also present a matching procedure based on the correlation coefficient, as a more robust alternative to squared error matching.

  18. Phase Retrieval From Multiple-Window Short-Time Fourier Measurements

    NASA Astrophysics Data System (ADS)

    Li, Lan; Cheng, Cheng; Han, Deguang; Sun, Qiyu; Shi, Guangming

    2017-04-01

    In this paper, we introduce two symmetric directed graphs depending on supports of signals and windows, and we show that the connectivity of those graphs provides either necessary and sufficient conditions to phase retrieval of a signal from magnitude measurements of its multiple-window short-time Fourier transform. Also we propose an algebraic reconstruction algorithm, and provide an error estimate to our algorithm when magnitude measurements are corrupted by deterministic/random noises.

  19. Inner composition alignment for inferring directed networks from short time series.

    PubMed

    Hempel, S; Koseska, A; Kurths, J; Nikoloski, Z

    2011-07-29

    Identifying causal links (couplings) is a fundamental problem that facilitates the understanding of emerging structures in complex networks. We propose and analyze inner composition alignment-a novel, permutation-based asymmetric association measure to detect regulatory links from very short time series, currently applied to gene expression. The measure can be used to infer the direction of couplings, detect indirect (superfluous) links, and account for autoregulation. Applications to the gene regulatory network of E. coli are presented.

  20. Short-Time Glassy Dynamics in Viscous Protein Solutions with Competing Interactions

    SciTech Connect

    Godfrin, P. Douglas; Hudson, Steven; Hong, Kunlun; Porcar, Lionel; Falus, Peter; Wagner, Norman; Liu, Yun

    2015-11-24

    Although there have been numerous investigations of the glass transition for colloidal dispersions with only a short-ranged attraction, less is understood for systems interacting with a long-ranged repulsion in addition to this attraction, which is ubiquitous in aqueous protein solutions at low ionic strength. Highly puri ed concentrated lysozyme solutions are used as a model system and investigated over a large range of protein concentrations at very low ionic strength. Newtonian liquid behavior is observed at all concentrations, even up to 480 mg/mL, where the zero shear viscosity increases by more than three orders of magnitude with increasing concentration. Remarkably, despite this macroscopic liquid-like behavior, the measurements of the dynamics in the short-time limit shows features typical of glassy colloidal systems. Investigation of the inter-protein structure indicates that the reduced short-time mobility of the protein is caused by localized regions of high density within a heterogeneous density distribution. This structural heterogeneity occurs on intermediate range length scale, driven by the competing potential features, and is distinct from commonly studied colloidal gel systems in which a heterogeneous density distribution tends to extend to the whole system. The presence of long-ranged repulsion also allows for more mobility over large length and long time scales resulting in the macroscopic relaxation of the structure. The experimental results provide evidence for the need to explicitly include intermediate range order in theories for the macroscopic properties of protein solutions interacting via competing potential features.

  1. Dramatic influence of patchy attractions on short-time protein diffusion under crowded conditions

    PubMed Central

    Bucciarelli, Saskia; Myung, Jin Suk; Farago, Bela; Das, Shibananda; Vliegenthart, Gerard A.; Holderer, Olaf; Winkler, Roland G.; Schurtenberger, Peter; Gompper, Gerhard; Stradner, Anna

    2016-01-01

    In the dense and crowded environment of the cell cytoplasm, an individual protein feels the presence of and interacts with all surrounding proteins. While we expect this to strongly influence the short-time diffusion coefficient Ds of proteins on length scales comparable to the nearest-neighbor distance, this quantity is difficult to assess experimentally. We demonstrate that quantitative information about Ds can be obtained from quasi-elastic neutron scattering experiments using the neutron spin echo technique. We choose two well-characterized and highly stable eye lens proteins, bovine α-crystallin and γB-crystallin, and measure their diffusion at concentrations comparable to those present in the eye lens. While diffusion slows down with increasing concentration for both proteins, we find marked variations that are directly linked to subtle differences in their interaction potentials. A comparison with computer simulations shows that anisotropic and patchy interactions play an essential role in determining the local short-time dynamics. Hence, our study clearly demonstrates the enormous effect that weak attractions can have on the short-time diffusion of proteins at concentrations comparable to those in the cellular cytosol. PMID:27957539

  2. On the simulation of protein folding by short time scale molecular dynamics and distributed computing.

    PubMed

    Fersht, Alan R

    2002-10-29

    There are proposals to overcome the current incompatibilities between the time scales of protein folding and molecular dynamics simulation by using a large number of short simulations of only tens of nanoseconds (distributed computing). According to the principles of first-order kinetic processes, a sufficiently large number of short simulations will include, de facto, a small number of long time scale events that have proceeded to completion. But protein folding is not an elementary kinetic step: folding has a series of early conformational steps that lead to lag phases at the beginning of the kinetics. The presence of these lag phases can bias short simulations toward selecting minor pathways that have fewer or faster lag steps and so miss the major folding pathways. Attempts to circumvent the lags by using loosely coupled parallel simulations that search for first-order transitions are also problematic because of the difficulty of detecting transitions in molecular dynamics simulations. Nevertheless, the procedure of using parallel independent simulations is perfectly valid and quite feasible once the time scale of simulation proceeds past the lag phases into a single exponential region.

  3. The short-term prediction of universal time and length of day using atmospheric angular momentum

    NASA Technical Reports Server (NTRS)

    Freedman, A. P.; Steppe, J. A.; Dickey, J. O.; Eubanks, T. M.; Sung, L.-Y.

    1994-01-01

    The ability to predict short-term variations in the Earth's rotation has gained importance in recent years owing to more precise spacecraft tracking requirements. Universal time (UT1), that component of the Earth's orientation corresponding to the rotation angle, can be measured by number of high-precision space geodetic techniques. A Kalman filter developed at the Jet Propulsion Laboratory (JPL) optimally combines these different data sets and generates a smoothed times series and a set of predictions for UT1, as well as for additional Earth orientation components. These UT1 predictions utilize an empirically derived random walk stochastic model for the length of the day (LOD) and require frequent and up-to-date measurements of either UT1 or LOD to keep errors from quickly accumulating. Recent studies have shown that LOD variations are correlated with changes in the Earth's axial atmospheric angular momentum (AAM) over timescales of several years down to as little as 8 days. AAM estimates and forecasts out to 10 days are routinely available from meteorological analysis centers; these data can supplement geodetic measurements to improve the short-term prediction of LOD and have therefore been incorporated as independent data types in the JPL Kalman filter. We find that AAM and, to a lesser extent, AAM forecast data are extremely helpful in generating accurate near-real-time estimates of UT1 and LOD and in improving short-term predictions of these quantities out to about 10 days.

  4. Administration time estimates for Wechsler Intelligence Scale for Children-IV subtests, composites, and short forms.

    PubMed

    Ryan, Joseph J; Glass, Laura A; Brown, Cassandra N

    2007-04-01

    The administration times for Wechsler Intelligence Scale for Children-IV (WISC-IV) subtests, indexes, and the Full Scale IQ were recorded for 57 school children. Also determined were administration times for eight short forms and the General Ability Index (GAI). All eight short forms reduced testing time by >50%, but the GAI required approximately 56 minutes. The time to administer the 10 core subtests that yield the Full Scale IQ and index scores averaged 72 minutes (range = 42 to 100), but 31% of the administrations required 80 minutes or longer. These results indicate that administration times are quite variable and that D. Wechsler's (2003) guideline of 65 to 80 minutes can be misleading for certain settings and for specific examinees. The present research found administration time to be positively correlated with examinee age, grade placement, and Full Scale IQ. In addition, the extent of examiner experience is known to be positively related to administration speed. In the present research, as in many settings, the examiners were competent, but not highly experienced.

  5. Quantifying complexity of financial short-term time series by composite multiscale entropy measure

    NASA Astrophysics Data System (ADS)

    Niu, Hongli; Wang, Jun

    2015-05-01

    It is significant to study the complexity of financial time series since the financial market is a complex evolved dynamic system. Multiscale entropy is a prevailing method used to quantify the complexity of a time series. Due to its less reliability of entropy estimation for short-term time series at large time scales, a modification method, the composite multiscale entropy, is applied to the financial market. To qualify its effectiveness, its applications in the synthetic white noise and 1 / f noise with different data lengths are reproduced first in the present paper. Then it is introduced for the first time to make a reliability test with two Chinese stock indices. After conducting on short-time return series, the CMSE method shows the advantages in reducing deviations of entropy estimation and demonstrates more stable and reliable results when compared with the conventional MSE algorithm. Finally, the composite multiscale entropy of six important stock indices from the world financial markets is investigated, and some useful and interesting empirical results are obtained.

  6. Molecular Weight Dependence of Interdiffusion and Adhesion of Polymers at Short Contact Times.

    PubMed

    Gurney, Robert; Henry, Anastase; Schach, Regis; Lindner, Anke; Creton, Costantino

    2017-02-21

    The autohesion and subsequent debonding of thin layers of three linear and monodisperse random copolymers of styrene-butadiene (SBR) with molecular weights varying between 30 and 75 times the average molecular weight between entanglements Me were investigated using a carefully controlled tack adhesion testing device in conjunction with a fast camera setup over a range of contact times tc (10 ms to 10 s) much shorter in comparison to the terminal relaxation times of the polymers. The evolution of the stress-strain curves and debonding mechanisms with increasing contact time was examined, and the work required to debond the layers was found to be strongly dependent on molecular weight at long contact times, but not at short contact times. We propose a cutoff contact time of 300 ms, corresponding to 10(4) times the entanglement time τe after which molecular weight becomes important in controlling the interdiffusion process and the debonding mechanisms of the tack test. For contact times over 300 ms, the debonding energy plotted as a function of tc normalized by the reptation time τrep, collapses onto a master curve. Below this threshold tc, by comparing the adhesion of SBR on itself with the adhesion of SBR on glass, we also show that interdiffusion plays a part in adhesion of two identical polymer layers even at the shortest contact times, where the interdiffusion is controlled by the number of entanglements formed which scales with 1/√N.

  7. Short time ion pulse extraction from the Dresden electron beam ion trapa)

    NASA Astrophysics Data System (ADS)

    Kentsch, U.; Zschornack, G.; Schwan, A.; Ullmann, F.

    2010-02-01

    We present measurements of the extraction of short time pulses of highly charged ions (4 keV, Ar16+) from the Dresden electron beam ion trap. Thereby the dependence of the extractable ionic charge on the extraction regime was investigated. The ion extraction time was varied between 20 ns and 1 μs. Furthermore the production of carbon ions and the influence of the extraction regime on the pulse widths was investigated to obtain information about the suitability of the Dresden EBIS-A in synchrotron based particle therapy facilities.

  8. Precision of Readout at the hunchback Gene: Analyzing Short Transcription Time Traces in Living Fly Embryos

    PubMed Central

    Tran, Huy; Ferraro, Teresa; Lucas, Tanguy; Guillou, Aurelien; Coppey, Mathieu; Dostatni, Nathalie

    2016-01-01

    The simultaneous expression of the hunchback gene in the numerous nuclei of the developing fly embryo gives us a unique opportunity to study how transcription is regulated in living organisms. A recently developed MS2-MCP technique for imaging nascent messenger RNA in living Drosophila embryos allows us to quantify the dynamics of the developmental transcription process. The initial measurement of the morphogens by the hunchback promoter takes place during very short cell cycles, not only giving each nucleus little time for a precise readout, but also resulting in short time traces of transcription. Additionally, the relationship between the measured signal and the promoter state depends on the molecular design of the reporting probe. We develop an analysis approach based on tailor made autocorrelation functions that overcomes the short trace problems and quantifies the dynamics of transcription initiation. Based on live imaging data, we identify signatures of bursty transcription initiation from the hunchback promoter. We show that the precision of the expression of the hunchback gene to measure its position along the anterior-posterior axis is low both at the boundary and in the anterior even at cycle 13, suggesting additional post-transcriptional averaging mechanisms to provide the precision observed in fixed embryos. PMID:27942043

  9. MONITORING SHORT-TERM COSMIC-RAY SPECTRAL VARIATIONS USING NEUTRON MONITOR TIME-DELAY MEASUREMENTS

    SciTech Connect

    Ruffolo, D.; Sáiz, A.; Mangeard, P.-S.; Kamyan, N.; Muangha, P.; Nutaro, T.; Rujiwarodom, M.; Tooprakai, P.; Sumran, S.; Chaiwattana, C.; Gasiprong, N.; Channok, C.; Wuttiya, C.; Asavapibhop, B.; Bieber, J. W.; Clem, J.; Evenson, P.; Munakata, K.

    2016-01-20

    Neutron monitors (NMs) are ground-based detectors of cosmic-ray showers that are widely used for high-precision monitoring of changes in the Galactic cosmic-ray (GCR) flux due to solar storms and solar wind variations. In the present work, we show that a single neutron monitor station can also monitor short-term changes in the GCR spectrum, avoiding the systematic uncertainties in comparing data from different stations, by means of NM time-delay histograms. Using data for 2007–2014 from the Princess Sirindhorn Neutron Monitor, a station at Doi Inthanon, Thailand, with the world’s highest vertical geomagnetic cutoff rigidity of 16.8 GV, we have developed an analysis of time-delay histograms that removes the chance coincidences that can dominate conventional measures of multiplicity. We infer the “leader fraction” L of neutron counts that do not follow a previous neutron count in the same counter from the same atmospheric secondary, which is inversely related to the actual multiplicity and increases for increasing GCR spectral index. After correction for atmospheric pressure and water vapor, we find that L indicates substantial short-term GCR spectral hardening during some but not all Forbush decreases in GCR flux due to solar storms. Such spectral data from Doi Inthanon provide information about cosmic-ray energies beyond the Earth’s maximum geomagnetic cutoff, extending the reach of the worldwide NM network and opening a new avenue in the study of short-term GCR decreases.

  10. Monitoring Short-term Cosmic-ray Spectral Variations Using Neutron Monitor Time-delay Measurements

    NASA Astrophysics Data System (ADS)

    Ruffolo, D.; Sáiz, A.; Mangeard, P.-S.; Kamyan, N.; Muangha, P.; Nutaro, T.; Sumran, S.; Chaiwattana, C.; Gasiprong, N.; Channok, C.; Wuttiya, C.; Rujiwarodom, M.; Tooprakai, P.; Asavapibhop, B.; Bieber, J. W.; Clem, J.; Evenson, P.; Munakata, K.

    2016-01-01

    Neutron monitors (NMs) are ground-based detectors of cosmic-ray showers that are widely used for high-precision monitoring of changes in the Galactic cosmic-ray (GCR) flux due to solar storms and solar wind variations. In the present work, we show that a single neutron monitor station can also monitor short-term changes in the GCR spectrum, avoiding the systematic uncertainties in comparing data from different stations, by means of NM time-delay histograms. Using data for 2007-2014 from the Princess Sirindhorn Neutron Monitor, a station at Doi Inthanon, Thailand, with the world’s highest vertical geomagnetic cutoff rigidity of 16.8 GV, we have developed an analysis of time-delay histograms that removes the chance coincidences that can dominate conventional measures of multiplicity. We infer the “leader fraction” L of neutron counts that do not follow a previous neutron count in the same counter from the same atmospheric secondary, which is inversely related to the actual multiplicity and increases for increasing GCR spectral index. After correction for atmospheric pressure and water vapor, we find that L indicates substantial short-term GCR spectral hardening during some but not all Forbush decreases in GCR flux due to solar storms. Such spectral data from Doi Inthanon provide information about cosmic-ray energies beyond the Earth’s maximum geomagnetic cutoff, extending the reach of the worldwide NM network and opening a new avenue in the study of short-term GCR decreases.

  11. The value in rushing: Memory and selectivity when short on time.

    PubMed

    Middlebrooks, Catherine D; Murayama, Kou; Castel, Alan D

    2016-10-01

    While being short on time can certainly limit what one remembers, are there always such costs? The current study investigates the impact of time constraints on selective memory and the self-regulated study of valuable information. Participants studied lists of words ranging in value from 1-10 points, with the goal being to maximize their score during recall. Half of the participants studied these words at a constant presentation rate of either 1 s or 5s. The other half of participants studied under both rates, either fast (1s) during the first several lists and then slow (5s) during later lists, or vice versa. Study was then self-paced during a final segment of lists for all participants to determine how people regulate their study time after experiencing different presentation rates during study. While participants recalled more words overall when studying at a 5-second rate, there were no significant differences in terms of value-based recall, with all participants demonstrating better recall for higher-valued words and similar patterns of selectivity, regardless of study time or prior timing experience. Self-paced study was also value-based, with participants spending more time studying high-value words than low-value. Thus, while being short on time may have impaired memory overall, participants' attention to item value during study was not differentially impacted by the fast and slow timing rates. Overall, these findings offer further insight regarding the influence that timing schedules and task experience have on how people selectively focus on valuable information.

  12. 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.

  13. Short time spreading and wetting of offset printing liquids on model calcium carbonate coating structures.

    PubMed

    Koivula, Hanna; Toivakka, Martti; Gane, Patrick

    2012-03-01

    Spreading of oils and water on porous and pre-saturated model carbonate coating structures was studied with high speed video imaging. The short-time data were complemented with long time absorption and wicking experiments. The results indicate a strong dependence between surface structural features of the pigment tablets and water spreading at short times, both in non-saturated and water pre-saturated cases, while the oil spreading is mainly dependent on the liquid properties. Sodium polyacrylate dispersant on pigment surfaces is shown to contribute to water spreading and absorption. On pre-saturated structures the liquid-liquid interactions are dominant and the majority of results support spreading according to the molecular kinetic model. The evidence supports the hypothesis of S. Rousu, P. Gane, and D. Eklund, ["Influence of coating pigment chemistry and morphology on the chromatographic separation of offset ink constituents," in The Science of Papermaking Transactions of the 12th Fundamental Research Symposium, FRC The Pulp & Paper Fundamental Research Society, Oxford, UK, 2001, p. 1115] that at long times the oils absorb into the porous structure at a rate proportional to the ratio of viscosity and surface tension, provided there is no sorptive action with the binder. A combination of nanosized pores and large surface area is useful for providing sufficient absorption capability for carbonate based coatings.

  14. Ordering and short-time orientational diffusion in dipolar hard-spherical colloids.

    PubMed

    Alarcón-Waess, O; Diaz-Herrera, E

    2002-03-01

    Orientational hydrodynamic functions and short-time, self-orientational and collective orientational diffusion coefficients of dipolar hard-spherical colloids are performed on a homogeneous isotropic phase, as functions of the wave vector q, for various values of the volume fraction and the dipolar strength of the macroparticles. The calculation is based on the dynamic orientational structure factor, which is the time-dependent self-correlation of the orientation density. We assume that the time evolution of the orientation density is given by the Smoluchoswki's equation, taking into account the hydrodynamic interactions as well as the dipolar interaction. The former are considered assuming pairwise additivity. The importance of the dynamic orientational structure factor is that its initial slope can be measured in a depolarized light scattering experiment. The results predict a different behavior for dilute and for dense dipolar colloids. The ordering phenomena are studied via the ordering coefficients, which are the orientational hydrodynamic functions at q=0. The results show that as the dipolar colloid evolves to the instability line, the translational ordering velocity increases while the rotational one reduces. The short-time orientational diffusion coefficients at q=0 are also performed. They predict that near to the instability line, the dipolar colloid diffuses translationally more than rotationally. At very dilute concentration the dipolar colloid presents an unexpected dynamical behavior, which seems to indicate that the colloid could be evolving to a reentrant phase.

  15. [Functional status of submariners after short-time submarine raid in the sea].

    PubMed

    Kalmanov, A S; Pisarev, A A; Khankevich, Yu R; Bloshchinskii, I A; Valskii, A V

    2015-10-01

    Short-time sea submarine raids (from a few days to a few weeks), performed during one working cycle, negatively influence on the functional state of the submariners organism. Upon returning to the point of basing the crew involved in the maintenance of the material and performs preparations for further access to the sea. Due to the high workload and lack of time personnel are not held in any correctional and rehabilitation activities, and therefore the time for the next release in the sea functional condition and functional reserves of the body does not have time to fully recover. The transfer of the submarine crew and referral to medical and psychological rehabilitation assumed only after the end of the operating cycle after the crew the task of further voyage. Based on the assessment of the functional systems of the submarine after a short voyage concluded on the need to develop a set of remedial measures for the recovery of submarine crews during inter-cruise period.

  16. Time functions of deep earthquakes from broadband and short-period stacks

    USGS Publications Warehouse

    Houston, H.; Benz, H.M.; Vidale, J.E.

    1998-01-01

    To constrain dynamic source properties of deep earthquakes, we have systematically constructed broadband time functions of deep earthquakes by stacking and scaling teleseismic P waves from U.S. National Seismic Network, TERRAscope, and Berkeley Digital Seismic Network broadband stations. We examined 42 earthquakes with depths from 100 to 660 km that occurred between July 1, 1992 and July 31, 1995. To directly compare time functions, or to group them by size, depth, or region, it is essential to scale them to remove the effect of moment, which varies by more than 3 orders of magnitude for these events. For each event we also computed short-period stacks of P waves recorded by west coast regional arrays. The comparison of broadband with short-period stacks yields a considerable advantage, enabling more reliable measurement of event duration. A more accurate estimate of the duration better constrains the scaling procedure to remove the effect of moment, producing scaled time functions with both correct timing and amplitude. We find only subtle differences in the broadband time-function shape with moment, indicating successful scaling and minimal effects of attenuation at the periods considered here. The average shape of the envelopes of the short-period stacks is very similar to the average broadband time function. The main variations seen with depth are (1) a mild decrease in duration with increasing depth, (2) greater asymmetry in the time functions of intermediate events compared to deep ones, and (3) unexpected complexity and late moment release for events between 350 and 550 km, with seven of the eight events in that depth interval displaying markedly more complicated time functions with more moment release late in the rupture than most events above or below. The first two results are broadly consistent with our previous studies, while the third is reported here for the first time. The greater complexity between 350 and 550 km suggests greater heterogeneity in

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

    PubMed Central

    Späti, 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

  18. Multiple short time power laws in the orientational relaxation of nematic liquid crystals.

    PubMed

    Jose, Prasanth P; Bagchi, Biman

    2006-11-14

    Relaxation in the nematic liquid crystalline phase is known to be sensitive to its proximity to both isotropic and smectic phases. Recent transient optical Kerr effect (OKE) studies have revealed, rather surprisingly, two temporal power laws at short to intermediate times and also an apparent absence of the expected exponential decay at longer times. In order to understand this unusual dynamics, we have carried out extensive molecular dynamics simulations of transient OKE and related orientational time correlation functions in a system of prolate ellipsoids (with aspect ratio equal to 3). The simulations find two distinct power laws, with a crossover region, in the decay of the orientational time correlation function at short to intermediate times (in the range of a few picoseconds to a few nanoseconds). In addition, the simulation results fail to recover any long time exponential decay component. The system size dependence of the exponents suggests that the first power law may originate from the local orientational density fluctuations (like in a glassy liquid). The origin of the second power law is less clear and may be related to the long range fluctuations (such as smecticlike density fluctuations)--these fluctuations are expected to involve small free energy barriers. In support of the latter, the evidence of pronounced coupling between orientational and spatial densities at intermediate wave numbers is presented. This coupling is usually small in normal isotropic liquids, but it is large in the present case. In addition to slow collective orientational relaxation, the single particle orientational relaxation is also found to exhibit slow dynamics in the nematic phase in the long time.

  19. Short-Time Glassy Dynamics in Viscous Protein Solutions with Competing Interactions

    DOE PAGES

    Godfrin, P. Douglas; Hudson, Steven; Hong, Kunlun; ...

    2015-11-24

    Although there have been numerous investigations of the glass transition for colloidal dispersions with only a short-ranged attraction, less is understood for systems interacting with a long-ranged repulsion in addition to this attraction, which is ubiquitous in aqueous protein solutions at low ionic strength. Highly puri ed concentrated lysozyme solutions are used as a model system and investigated over a large range of protein concentrations at very low ionic strength. Newtonian liquid behavior is observed at all concentrations, even up to 480 mg/mL, where the zero shear viscosity increases by more than three orders of magnitude with increasing concentration. Remarkably,more » despite this macroscopic liquid-like behavior, the measurements of the dynamics in the short-time limit shows features typical of glassy colloidal systems. Investigation of the inter-protein structure indicates that the reduced short-time mobility of the protein is caused by localized regions of high density within a heterogeneous density distribution. This structural heterogeneity occurs on intermediate range length scale, driven by the competing potential features, and is distinct from commonly studied colloidal gel systems in which a heterogeneous density distribution tends to extend to the whole system. The presence of long-ranged repulsion also allows for more mobility over large length and long time scales resulting in the macroscopic relaxation of the structure. The experimental results provide evidence for the need to explicitly include intermediate range order in theories for the macroscopic properties of protein solutions interacting via competing potential features.« less

  20. Thick-target bremsstrahlung interpretation of short time-scale solar hard X-ray features

    NASA Technical Reports Server (NTRS)

    Emslie, A. G.

    1983-01-01

    Steady-state analyses of bremsstrahlung hard X-ray production in solar flares are appropriate only if the lifetime of the high energy electrons in the X-ray source is much shorter than the duration of the observed X-ray burst. For a thick-target nonthermal model, this implies that a full time-dependent analysis is required when the duration of the burst is comparable to the collisional lifetime of the injected electrons, in turn set by the lengths and densities of the flaring region. In this paper we present the results of such a time-dependent analysis, and we point out that the intrinsic temporal signature of the thick-target production mechanism, caused by the finite travel time of the electrons through the target, may indeed rule out such a mechanism for extremely short duration hard X-ray events.

  1. Variations in Sleep and Performance by Duty Start Time in Short Haul Operations

    NASA Technical Reports Server (NTRS)

    Flynn-Evans, Erin

    2016-01-01

    Prior studies have confirmed that commercial airline pilots experience circadian phase shifts and short sleep duration following travel with layovers in different time zones. Few studies have examined the impact of early and late starts on the sleep and circadian phase of airline pilots who return to their domicile after each duty period. We recruited 44 pilots (4 female) from a short-haul commercial airline to participate in a study examining sleep and circadian phase over four duty schedules (baseline, early starts, mid-day starts, late starts). Each duty schedule was five days long, separated by three rest days. Participants completed the rosters in the same order. Sleep outcomes were estimated using wrist-borne actigraphy (Actiware Software, Respironics, Bend, OR) and daily sleep diaries. Thirteen participants volunteered to collect urine samples for the assessment of 6-sulfatoxymelatonin (aMT6s). Urine samples were collected in four-hourly bins during the day and eight-hourly bins during sleep episodes, for 24 hours immediately following each experimental duty schedule. The aMT6s results were fit to a cosine in order to obtain the acrophase to estimate circadian phase. Univariate statistics were calculated for acrophase changes, schedule start times and sleep times. All statistical analyses were computed using SAS software (Cary, IN).

  2. Combining phase images from array coils using a short echo time reference scan (COMPOSER)

    PubMed Central

    Dymerska, Barbara; Bogner, Wolfgang; Barth, Markus; Zaric, Olgica; Goluch, Sigrun; Grabner, Günther; Deligianni, Xeni; Bieri, Oliver; Trattnig, Siegfried

    2015-01-01

    Purpose To develop a simple method for combining phase images from multichannel coils that does not require a reference coil and does not entail phase unwrapping, fitting or iterative procedures. Theory and Methods At very short echo time, the phase measured with each coil of an array approximates to the phase offset to which the image from that coil is subject. Subtracting this information from the phase of the scan of interest matches the phases from the coils, allowing them to be combined. The effectiveness of this approach is quantified in the brain, calf and breast with coils of diverse designs. Results The quality of phase matching between coil elements was close to 100% with all coils assessed even in regions of low signal. This method of phase combination was similar in effectiveness to the Roemer method (which needs a reference coil) and was superior to the rival reference‐coil‐free approaches tested. Conclusion The proposed approach—COMbining Phase data using a Short Echo‐time Reference scan (COMPOSER)—is a simple and effective approach to reconstructing phase images from multichannel coils. It requires little additional scan time, is compatible with parallel imaging and is applicable to all coils, independent of configuration. Magn Reson Med 77:318–327, 2017. © 2015 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine PMID:26712454

  3. Short Contact Time Direct Coal Liquefaction Using a Novel Batch Reactor

    SciTech Connect

    He Huang; Michael T. Klein; William H. Calkins

    1997-04-03

    The primary objective of this research is to optimize the design and operation of the bench scale batch reactor (SCTBR) for studying direct coal liquefaction at short contact times (.01 to 10 minutes or longer) . An additional objective is to study the kinetics of direct coal liquefaction particularly at short reaction times. Both of these objectives have been nearly achieved, however this work has shown the great importance of the liquefaction solvent characteristics and the solvent-catalyst interaction on the liquefaction process. This has prompted us to do a preliminary investigation of solvents and the solvent-catalyst systems in coal liquefaction. SUMMARY AND CONCLUSIONS 1) Conversion vs time data have been extended to 5 coals of ranks from lignite to low volatile bituminous coal. A broad range of reaction rates have been observed with a maximum in the high volatile bituminous range. 2) A series of direct coal liquefaction runs have been made using a range of nitrogen containing solvents that given high liquefaction conversions of coal. These runs are now being analyzed. 3) The coalification process has been shown by TGA to go through an intermediate stage which may account for the greater reactivity of bituminous coals in the direct coal liquefaction process. 4) It was shown that coal rank can be accurately determined by thermogravimetric analysis

  4. Automated control and monitoring of thermal processing using high temperature, short time pasteurization.

    PubMed

    Schlesser, J E; Armstrong, D J; Cinar, A; Ramanauskas, P; Negiz, A

    1997-10-01

    High temperature, short time pasteurization was used to evaluate a computer-based system for controlling the pasteurization process, acquiring data, and monitoring records. Software was used for the control of hot water temperature, flow rate through the centrifugal timing pump, and diversion of under-processed product. Three types of control strategies were conducted: single loop, cascade, and multivariable. The single loop control strategy showed the most rapid responses to temperature changes, but the temperature response curve was slowest to return to its set point. The cascade control strategy showed slower recoveries to temperature changes, but the temperature response curve was smoother. The multivariable control strategy responded slightly faster than the cascade control strategy, and the temperature response curve was slightly smoother than the cascade control strategy. The multivariable control strategy was able to control the flow diversion valve by the use of a lethality controller. The data acquisition system, used to monitor the data obtained from the high temperature, short-time pasteurization system, was within +/- 0.1 degree C of the temperature recorded by the safety thermal limit recorder. Reliability was determined by examining the changes in the position of the flow diversion valve to identify process deviations and by comparing the changes to the event marker on circular charts. The data acquisition system was an effective alternative for monitoring the completeness of data.

  5. Magnetic Reconnection Sites Observed by the Cluster Spacecraft: Measurement of Short time scale electron effects

    NASA Astrophysics Data System (ADS)

    Buckley, A. M.; Carozzi, T. C.; Gough, M. P.; Chambers, E. C.

    Several events have been observed by the Cluster spacecraft passing close to magnetic reconnection sites in the tail and magnetopause when the fleet configuration is at short spatial scale (spacecraft separation approximately 100 km). These events are studied in the context of corresponding short time scale electron behaviour which contribute to and result from the reconnection process. This is done primarily using Particle Correlator data from the DWP instruments on Cluster in conjunction with other data sets. The particle correlators use captured time series of electron particle counts accumulated in 12 microsecond time bins measured over the energy range of the PEACE HEEA sensor (40 eV to 26 KeV) and on which an auto-correlation is performed. The phenomena studied concerns beam properties, electron acceleration, interaction with waves and any indications of the electron diffusion processes that are occurring. These phenomena are quantified using measures of the strength of particle-particle interactions (general second order statistics on the electrons) and the Index of Dispersion (variance to mean ratio) indicating bunching or scattering processes.

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

    SciTech Connect

    Smijesh, N.; Chandrasekharan, K.; Joshi, Jagdish C.; Philip, Reji

    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 10⁻⁶Torr to 10²Torr, 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 (3d⁹(²D) 4p → 3d⁹(²D) 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 (3p⁶3d⁸(³P) 4s→ 3p⁶3d⁹ 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.

  7. 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.

  8. Quantum coherence effects in hybrid nanoparticle molecules in the presence of ultra-short dephasing times

    NASA Astrophysics Data System (ADS)

    Sadeghi, S. M.

    2012-11-01

    We study quantum coherence effects in single nanoparticle systems consisting of a semiconductor quantum dot and a metallic nanoparticle in the presence of the ultra-short dephasing times of the quantum dots. The results suggest that coherent exciton-plasmon coupling can sustain the collective molecular resonances (plasmonic meta-resonances) of these systems at about room temperature. We investigate quantum optical properties of the quantum dots under this condition, demonstrating formation of ultranarrow gain and absorption spectral lines. These results are discussed in terms of plasmonic normalization of coherent population oscillation and the collective states of the nanoparticle systems.

  9. A short time existence/uniqueness result for a nonlocal topology-preserving segmentation model

    NASA Astrophysics Data System (ADS)

    Forcadel, Nicolas; Le Guyader, Carole

    Motivated by a prior applied work of Vese and the second author dedicated to segmentation under topological constraints, we derive a slightly modified model phrased as a functional minimization problem, and propose to study it from a theoretical viewpoint. The mathematical model leads to a second order nonlinear PDE with a singularity at Du=0 and containing a nonlocal term. A suitable setting is thus the one of the viscosity solution theory and, in this framework, we establish a short time existence/uniqueness result as well as a Lipschitz regularity result for the solution.

  10. Significance of time awake for predicting pilots' fatigue on short-haul flights: implications for flight duty time regulations.

    PubMed

    Vejvoda, Martin; Elmenhorst, Eva-Maria; Pennig, Sibylle; Plath, Gernot; Maass, Hartmut; Tritschler, Kristjof; Basner, Mathias; Aeschbach, Daniel

    2014-10-01

    European regulations restrict the duration of the maximum daily flight duty period for pilots as a function of the duty start time and the number of scheduled flights. However, late duty end times that may include long times awake are not specifically regulated. In this study, fatigue levels in pilots finishing their duty late at night (00:00-01:59 hour) were analysed and compared with pilots starting their duty early (05:00-06:59 hour). Fatigue levels of 40 commercial short-haul pilots were studied during a total of 188 flight duty periods, of which 87 started early and 22 finished late. Pilots used a small handheld computer to maintain a duty and sleep log, and to indicate fatigue levels immediately after each flight. Sleep logs were checked with actigraphy. Pilots on late-finishing flight duty periods were more fatigued at the end of their duty than pilots on early-starting flight duty periods, despite the fact that preceding sleep duration was longer by 1.1 h. Linear mixed-model regression identified time awake as a preeminent factor predicting fatigue. Workload had a minor effect. Pilots on late-finishing flight duty periods were awake longer by an average of 5.5 h (6.6 versus 1.1 h) before commencing their duty than pilots who started early in the morning. Late-finishing flights were associated with long times awake at a time when the circadian system stops promoting alertness, and an increased, previously underestimated fatigue risk. Based on these findings, flight duty limitations should consider not only duty start time, but also the time of the final landing.

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

    PubMed Central

    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, Richard E.; Hogg, James C.; Battafarano, Richard J.; Cooper, Joel D.; Meyers, Bryan F.; Patterson, G. Alexander; Yablonskiy, Dmitriy A.; Conradi, Mark S.

    2010-01-01

    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. Conclusion Decreases in ADC with longer diffusion time were unrelated to emphysema severity. The strong correlations between the ADC at all diffusion times tested and quantitative histology demonstrate that the ADC is a robust measure of emphysema. PMID:19787725

  12. Estimation of ultrasound attenuation and dispersion using short time Fourier transform.

    PubMed

    Zhao, B; Basir, O A; Mittal, G S

    2005-03-01

    Determination of the acoustic attenuation and dispersion has important applications in ultrasound tissue characterization and non-destructive material testing. Current signal processing methods Fourier transform of ultrasound signals to get the spectra of amplitude and phase to estimate respectively the attenuation and dispersion of a given medium. These methods are frequency domain method and obsessed with ambiguity issue in the phase unwrapping calculation. Conventional ultrasound velocity measuring method detects the time of arrival of a pulse (or echo) signal, which is a time domain method to compute group velocity (not phase velocity). This paper presents a novel approach based on the short time Fourier transform (STFT)--a time-frequency analysis, to estimate the ultrasonic dispersion and attenuation. Only the amplitude information of the pulse-signal spectra is used. Based on the time-frequency presentation, the attenuation coefficient of the signal is obtained by computing the amplitude decay of pulse spectrum in time domain, while phase velocities are obtained based on the "time-of-flight" (TOF) of the mono frequency component of the pulse signals. As a result, we eliminate the ambiguity issue in phase angle calculation. Furthermore, the proposed method makes the phase velocity pedagogically intuitive for novice users. The paper presents experiments to evaluate demonstrate the performance of the proposed method.

  13. 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.

  14. Evidence of Different Propofol Pharmacokinetics under Short and Prolonged Infusion Times in Rabbits.

    PubMed

    Campos, Sónia; Monteiro, Joaquim; Valenzuela, Belén; Gonçalinho, Helena; de Pinho, Paula Guedes; Fresco, Paula; Félix, Luis; Antunes, Luís

    2016-06-01

    Propofol is an anaesthetic widely used in both human beings and animals. However, the characterization of propofol pharmacokinetics (PK) is not well understood when long-term infusions are used. The main objective of this study was to explore the PK behaviour of propofol in a rabbit model during short and prolonged propofol infusions and to develop an internally validated PK model, for propofol dose individualization in the rabbit for future use. Population 1 (P1) was constituted by seven New Zealand rabbits and was used to characterize the PK profile of propofol at short infusions. Animals were anaesthetized with a bolus of 20 mg/kg, followed by an infusion rate of 50 mg/kg/hr of propofol at 1%, which was then maintained for 30 min. A second rabbit population (P2, n = 7) was sedated according to reflexes responses and Index of Consciousness values, for 20 consecutive hours using propofol 2% aiming at characterizing propofol behaviour at long-term infusions. Clinical data and blood samples were collected at specific time-points in both populations. Propofol plasma concentrations were determined by gas chromatography/ion trap mass spectrometry. The NONMEM VII software was used to evaluate the relationships between dose and plasma concentrations. A linear two-compartment model with different central compartment volume and plasma clearance (separately modelled in the two populations) was the one that best described propofol concentrations. The time course of propofol plasma concentrations was well characterized by the PK model developed, which simultaneously accounts for propofol short- and long-term infusions and can be used to optimize future PK studies in rabbits.

  15. Decomposing a signal into short-time narrow-banded modes

    NASA Astrophysics Data System (ADS)

    McNeill, S. I.

    2016-07-01

    An algorithm for nonparametric decomposition of a signal into the sum of short-time narrow-banded modes (components) is introduced. Specifically, the signal data is augmented with its Hilbert transform to obtain the analytic signal. Then the set of constituent amplitude and frequency modulated (AM-FM) analytic sinusoids, each with slowly varying amplitude and frequency, is sought. The method for obtaining the short-time narrow-banded modes is derived by minimizing an objective function comprised of three criteria: smoothness of the instantaneous amplitude envelope, smoothness of the instantaneous frequency and complete reconstruction of the signal data. A minimum of the objective function is approached using a sequence of suboptimal updates of amplitude and phase. The updates are intuitive, efficient and simple to implement. For a given mode, the amplitude and phase are extracted from the band-pass filtered residual (signal after the other modes are removed), where the band-pass filter is applied about the previous modal instantaneous frequency estimate. The method is demonstrated by application to random output-only vibration data and order tracking data. It is demonstrated that vibration modal responses can be estimated from single channel data and order tracking can be performed without measured tachometer data.

  16. Multivariate time series modeling of short-term system scale irrigation demand

    NASA Astrophysics Data System (ADS)

    Perera, Kushan C.; Western, Andrew W.; George, Biju; Nawarathna, Bandara

    2015-12-01

    Travel time limits the ability of irrigation system operators to react to short-term irrigation demand fluctuations that result from variations in weather, including very hot periods and rainfall events, as well as the various other pressures and opportunities that farmers face. Short-term system-wide irrigation demand forecasts can assist in system operation. Here we developed a multivariate time series (ARMAX) model to forecast irrigation demands with respect to aggregated service points flows (IDCGi, ASP) and off take regulator flows (IDCGi, OTR) based across 5 command areas, which included area covered under four irrigation channels and the study area. These command area specific ARMAX models forecast 1-5 days ahead daily IDCGi, ASP and IDCGi, OTR using the real time flow data recorded at the service points and the uppermost regulators and observed meteorological data collected from automatic weather stations. The model efficiency and the predictive performance were quantified using the root mean squared error (RMSE), Nash-Sutcliffe model efficiency coefficient (NSE), anomaly correlation coefficient (ACC) and mean square skill score (MSSS). During the evaluation period, NSE for IDCGi, ASP and IDCGi, OTR across 5 command areas were ranged 0.98-0.78. These models were capable of generating skillful forecasts (MSSS ⩾ 0.5 and ACC ⩾ 0.6) of IDCGi, ASP and IDCGi, OTR for all 5 lead days and IDCGi, ASP and IDCGi, OTR forecasts were better than using the long term monthly mean irrigation demand. Overall these predictive performance from the ARMAX time series models were higher than almost all the previous studies we are aware. Further, IDCGi, ASP and IDCGi, OTR forecasts have improved the operators' ability to react for near future irrigation demand fluctuations as the developed ARMAX time series models were self-adaptive to reflect the short-term changes in the irrigation demand with respect to various pressures and opportunities that farmers' face, such as

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

    NASA Technical Reports Server (NTRS)

    Wie, Bong; Barbee, Brent W.

    2015-01-01

    This paper presents the results of a NASA Innovative Advanced Concept (NIAC) Phase 2 study entitled "An Innovative Solution to NASA's Near-Earth Object (NEO) Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development." This NIAC Phase 2 study was conducted at the Asteroid Deflection Research Center (ADRC) of Iowa State University in 2012-2014. The study objective was to develop an innovative yet practically implementable mitigation strategy for the most probable impact threat of an asteroid or comet with short warning time (less than 5 years). The mitigation strategy described in this paper is intended to optimally reduce the severity and catastrophic damage of the NEO impact event, especially when we don't have sufficient warning times for non-disruptive deflection of a hazardous NEO. This paper provides an executive summary of the NIAC Phase 2 study results.

  18. Verification of short lead time forecast models: applied to Kp and Dst forecasting

    NASA Astrophysics Data System (ADS)

    Wintoft, Peter; Wik, Magnus

    2016-04-01

    In the ongoing EU/H2020 project PROGRESS models that predicts Kp, Dst, and AE from L1 solar wind data will be used as inputs to radiation belt models. The possible lead times from L1 measurements are shorter (10s of minutes to hours) than the typical duration of the physical phenomena that should be forecast. Under these circumstances several metrics fail to single out trivial cases, such as persistence. In this work we explore metrics and approaches for short lead time forecasts. We apply these to current Kp and Dst forecast models. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637302.

  19. Characterizing the frequency response curve of large rooms in the short and long time regimes

    NASA Astrophysics Data System (ADS)

    Klales, Anna; Pittman, Suzanne; Barr, Matthew; Borunda, Mario; Heller, Eric

    2012-02-01

    Room acoustics can be modeled by real Gaussian statistics, corresponding to randomized ray trajectories and characterized for instance by the reverberation time T60 (free field to decay by 60 decibels) which is independent of position or source point in a room. In his 1954 paper, Manfred Schroeder found universal statistical features of the steady state frequency response curve of large rooms, based upon the assumption of Gaussian probability distributions of the pressure. For example, he found the standard deviation from the mean level is 11 decibels for any concert hall, regardless of the shape of the room or its T60, within reasonable limits. Using semi-classical and numerical methods, we find non-universal (room dependent) corrections to Schroeder's universal results for the statistics of the frequency response curve. Along with corrections to the steady-state frequency response, we present the behavior of the frequency response curve for short to intermediate times.

  20. Salt marsh mapping based on a short-time interval NDVI time-series from HJ-1 CCD imagery

    NASA Astrophysics Data System (ADS)

    SUN, C.

    2015-12-01

    Salt marshes are regard as one of the most dynamic and valuable ecosystems in coastal zone. It is crucial to obtain accurate information on the species composition and spatial distribution of salt marshes in time since they are experiencing tremendous replacement and disappearance. However, discriminating various types of salt marshes is a rather difficult task because of the strong spectral similarities. In previous studies, salt marsh mappings were mainly focused on high-spatial and hyperspectral resolution imageries combined with auxiliary information but this method can hardly extend to a large region. With high temporal and moderate spatial resolutions, Chinese HJ-1 CCD imagery would not only allow monitoring phenological changes of salt marsh vegetation in short-time intervals, but also cover large areas of salt marshes. Taking the middle coast of Jiangsu (east China) as an example, our study first constructed a monthly NDVI time-series to classify various types of salt marshes. Then, we tested the idea of compressed time-series continuously to broaden the applicability and portability of this particular approach. The results showed that (1) the overall accuracy of salt marsh mapping based on the monthly NDVI time-series reached 90.3%, which increased approximately 16.0% in contrast with a single-phase classification strategy; (2) a compressed time-series, including NDVI from six key months (April, June to September, and November) demonstrated very little decline (2.3%) in overall accuracy but led to obvious improvements in unstable regions; (3) Spartina alterniflora identification could be achieved with only a scene NDVI image from November, which could provide an effective way to regularly monitor its distribution. Besides, by comparing the calibrated performance between HJ-1 CCD and other sensors (i.e., Landsat TM/ETM+, OLI), we certified the reliability of HJ-1 CCD imagery, which is expected to pave the way for laws expansibility from this imagery.

  1. 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.

  2. Asymptotic structure of electrodynamics revisited

    NASA Astrophysics Data System (ADS)

    Herdegen, Andrzej

    2017-03-01

    We point out that recently published analyses of null and timelike infinity and long-range structures in electrodynamics to large extent rediscover results present in the literature. At the same time, some of the conclusions these recent works put forward may prove controversial. In view of these facts, we find it desirable to revisit the analysis taken up more than two decades ago, starting from earlier works on null infinity by other authors.

  3. 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.

  4. An analytic algorithm for global coverage of the revisiting orbit and its application to the CFOSAT satellite

    NASA Astrophysics Data System (ADS)

    Xu, Ming; Huang, Li

    2014-08-01

    This paper addresses a new analytic algorithm for global coverage of the revisiting orbit and its application to the mission revisiting the Earth within long periods of time, such as Chinese-French Oceanic Satellite (abbr., CFOSAT). In the first, it is presented that the traditional design methodology of the revisiting orbit for some imaging satellites only on the single (ascending or descending) pass, and the repeating orbit is employed to perform the global coverage within short periods of time. However, the selection of the repeating orbit is essentially to yield the suboptimum from the rare measure of rational numbers of passes per day, which will lose lots of available revisiting orbits. Thus, an innovative design scheme is proposed to check both rational and irrational passes per day to acquire the relationship between the coverage percentage and the altitude. To improve the traditional imaging only on the single pass, the proposed algorithm is mapping every pass into its ascending and descending nodes on the specified latitude circle, and then is accumulating the projected width on the circle by the field of view of the satellite. The ergodic geometry of coverage percentage produced from the algorithm is affecting the final scheme, such as the optimal one owning the largest percentage, and the balance one possessing the less gradient in its vicinity, and is guiding to heuristic design for the station-keeping control strategies. The application of CFOSAT validates the feasibility of the algorithm.

  5. High nitrogen removal rate using ANAMMOX process at short hydraulic retention time.

    PubMed

    Casagrande, C G; Kunz, A; De Prá, M C; Bressan, C R; Soares, H M

    2013-01-01

    The anaerobic ammonium oxidation (ANAMMOX) is a chemolithoautotrophic process, which converts NH(4)(+) to N(2) using nitrite (NO(2)(-)) as the electron acceptor. This process has very high nitrogen removal rates (NRRs) and is an alternative to classical nitrification/denitrification wastewater treatment. In the present work, a strategy for nitrogen removal using ANAMMOX process was tested evaluating their performance when submitted to high loading rates and very short hydraulic retention times (HRTs). An up-flow ANAMMOX column reactor was inoculated with 30% biomass (v v(-1)) fed from 100 to 200 mg L(-1) of total N (NO(2)(-)-N + NH(4)(+)-N) at 35 °C. After start-up and process stability the maximum NRR in the up-flow anaerobic sludge blanket (UASB) reactor was 18.3 g-N L(-1) d(-1) operated at 0.2 h of HRT. FISH (fluorescence in situ hybridization) analysis and process stoichiometry confirmed that ANAMMOX was the prevalent process for nitrogen removal during the experiments. The results point out that high NRRs can be obtained at very short HRTs using up-flow ANAMMOX column reactor configuration.

  6. Fluctuation of similarity (FLUS) to detect transitions between distinct dynamical regimes in short time series

    PubMed Central

    Malik, Nishant; Marwan, Norbert; Zou, Yong; Mucha, Peter J.; Kurths, Jürgen

    2016-01-01

    A method to identify distinct dynamical regimes and transitions between those regimes in a short univariate time series was recently introduced [1], employing the computation of fluctuations in a measure of nonlinear similarity based on local recurrence properties. In the present work, we describe the details of the analytical relationships between this newly introduced measure and the well known concepts of attractor dimensions and Lyapunov exponents. We show that the new measure has linear dependence on the effective dimension of the attractor and it measures the variations in the sum of the Lyapunov spectrum. To illustrate the practical usefulness of the method, we identify various types of dynamical transitions in different nonlinear models. We present testbed examples for the new method’s robustness against noise and missing values in the time series. We also use this method to analyze time series of social dynamics, specifically an analysis of the U.S. crime record time series from 1975 to 1993. Using this method, we find that dynamical complexity in robberies was influenced by the unemployment rate until the late 1980’s. We have also observed a dynamical transition in homicide and robbery rates in the late 1980’s and early 1990’s, leading to increase in the dynamical complexity of these rates. PMID:25019852

  7. Effects of stimulus intensity on latency and conduction time of short-latency somatosensory evoked potentials.

    PubMed

    Shiga, Y; Yamada, T; Ofuji, A; Fujita, Y; Kawamura, T; Inoue, K; Hada, Y; Yamazaki, H; Cheng, M H; Yeh, M H

    2001-04-01

    We studied the effect of stimulus intensity on latencies of short-latency somatosensory evoked potentials (SSEP) by measuring both onset and peak latencies individually. The latencies of N9, N13, N20 and N9-N13 peripheral conduction time (PCT) of median nerve (MN) SSEP, and N8, N23, P37 and N8-N23 PCT of tibial nerve (TN) and sural nerve (SN) SSEP significantly shortened with increasing stimulus intensity by onset latency measurement. However, those latencies by peak latency measurement were less significantly shortened or had only a trend of latency shortening without statistical significance. In contrast to PCT, N13-N20 central conduction time (CCT) of MN-SSEP and N23-P37 CCT of TN- or SN-SSEP showed no latency changes with the increased stimulus intensity by both onset and peak latencies measurement. As peak latencies had greater interindividual variability than onset latencies shown by larger standard deviation, shortening of onset latencies were more consistent than that of peak latencies. We think shortening of onset latencies indicates the recruitment of faster conduction fiber along with increased stimulus intensity. As the degree of latency shortening was less if stimulus intensity was above 2.5 times sensory threshold, the stimulus intensity greater than 2.5 times the sensory threshold should be used for clinical application.

  8. Fluctuation of similarity to detect transitions between distinct dynamical regimes in short time series

    NASA Astrophysics Data System (ADS)

    Malik, Nishant; Marwan, Norbert; Zou, Yong; Mucha, Peter J.; Kurths, Jürgen

    2014-06-01

    A method to identify distinct dynamical regimes and transitions between those regimes in a short univariate time series was recently introduced [N. Malik et al., Europhys. Lett. 97, 40009 (2012), 10.1209/0295-5075/97/40009], employing the computation of fluctuations in a measure of nonlinear similarity based on local recurrence properties. In this work, we describe the details of the analytical relationships between this newly introduced measure and the well-known concepts of attractor dimensions and Lyapunov exponents. We show that the new measure has linear dependence on the effective dimension of the attractor and it measures the variations in the sum of the Lyapunov spectrum. To illustrate the practical usefulness of the method, we identify various types of dynamical transitions in different nonlinear models. We present testbed examples for the new method's robustness against noise and missing values in the time series. We also use this method to analyze time series of social dynamics, specifically an analysis of the US crime record time series from 1975 to 1993. Using this method, we find that dynamical complexity in robberies was influenced by the unemployment rate until the late 1980s. We have also observed a dynamical transition in homicide and robbery rates in the late 1980s and early 1990s, leading to increase in the dynamical complexity of these rates.

  9. Qualitative Features Extraction from Sensor Data using Short-time Fourier Transform

    NASA Technical Reports Server (NTRS)

    Amini, Abolfazl M.; Figueroa, Fernando

    2004-01-01

    The information gathered from sensors is used to determine the health of a sensor. Once a normal mode of operation is established any deviation from the normal behavior indicates a change. This change may be due to a malfunction of the sensor(s) or the system (or process). The step-up and step-down features, as well as sensor disturbances are assumed to be exponential. An RC network is used to model the main process, which is defined by a step-up (charging), drift, and step-down (discharging). The sensor disturbances and spike are added while the system is in drift. The system runs for a period of at least three time-constants of the main process every time a process feature occurs (e.g. step change). The Short-Time Fourier Transform of the Signal is taken using the Hamming window. Three window widths are used. The DC value is removed from the windowed data prior to taking the FFT. The resulting three dimensional spectral plots provide good time frequency resolution. The results indicate distinct shapes corresponding to each process.

  10. Fluctuation of similarity to detect transitions between distinct dynamical regimes in short time series.

    PubMed

    Malik, Nishant; Marwan, Norbert; Zou, Yong; Mucha, Peter J; Kurths, Jürgen

    2014-06-01

    A method to identify distinct dynamical regimes and transitions between those regimes in a short univariate time series was recently introduced [N. Malik et al., Europhys. Lett. 97, 40009 (2012)], employing the computation of fluctuations in a measure of nonlinear similarity based on local recurrence properties. In this work, we describe the details of the analytical relationships between this newly introduced measure and the well-known concepts of attractor dimensions and Lyapunov exponents. We show that the new measure has linear dependence on the effective dimension of the attractor and it measures the variations in the sum of the Lyapunov spectrum. To illustrate the practical usefulness of the method, we identify various types of dynamical transitions in different nonlinear models. We present testbed examples for the new method's robustness against noise and missing values in the time series. We also use this method to analyze time series of social dynamics, specifically an analysis of the US crime record time series from 1975 to 1993. Using this method, we find that dynamical complexity in robberies was influenced by the unemployment rate until the late 1980s. We have also observed a dynamical transition in homicide and robbery rates in the late 1980s and early 1990s, leading to increase in the dynamical complexity of these rates.

  11. Retention time generates short-term phytoplankton blooms in a shallow microtidal subtropical estuary

    NASA Astrophysics Data System (ADS)

    Odebrecht, Clarisse; Abreu, Paulo C.; Carstensen, Jacob

    2015-09-01

    In this study it was hypothesised that increasing water retention time promotes phytoplankton blooms in the shallow microtidal Patos Lagoon estuary (PLE). This hypothesis was tested using salinity variation as a proxy of water retention time and chlorophyll a for phytoplankton biomass. Submersible sensors fixed at 5 m depth near the mouth of PLE continuously measured water temperature, salinity and pigments fluorescence (calibrated to chlorophyll a) between March 2010 and 12th of December 2011, with some gaps. Salinity variations were used to separate alternating patterns of outflow of lagoon water (salinity <8; 46% of the time) and inflow of marine water (salinity >24; 35% of the time). The two transition phases represented a rapid change from lagoon water outflow to marine water inflow and a more gradually declining salinity between the dominating inflow and outflow conditions. During the latter of these, a significant chlorophyll a increase relative to that expected from a linear mixing relationship was observed at intermediate salinities (10-20). The increase in chlorophyll a was positively related to the duration of the prior coastal water inflow in the PLE. Moreover, chlorophyll a increase was significantly higher during austral spring-summer than autumn-winter, probably due to higher light and nutrient availability in the former. Moreover, the retention time process operating on time scales of days influences the long-term phytoplankton variability in this ecosystem. Comparing these results with monthly data from a nearby long-term water quality monitoring station (1993-2011) support the hypothesis that chlorophyll a accumulations occur after marine inflow events, whereas phytoplankton does not accumulate during high water outflow, when the water residence time is short. These results suggest that changing hydrological pattern is the most important mechanism underlying phytoplankton blooms in the PLE.

  12. Intrinsic dynamics of heart regulatory systems on short time-scales: from experiment to modelling

    PubMed Central

    Khovanov, I. A.; Khovanova, N. A.; McClintock, P. V. E.; Stefanovska, A.

    2010-01-01

    We discuss open problems related to the stochastic modeling of cardiac function. The work is based on an experimental investigation of the dynamics of heart rate variability (HRV) in the absence of respiratory perturbations. We consider first the cardiac control system on short time scales via an analysis of HRV within the framework of a random walk approach. Our experiments show that HRV on timescales of less than a minute takes the form of free diffusion, close to Brownian motion, which can be described as a non-stationary process with stationary increments. Secondly, we consider the inverse problem of modeling the state of the control system so as to reproduce the experimentally observed HRV statistics of. We discuss some simple toy models and identify open problems for the modelling of heart dynamics. PMID:21151767

  13. Methanosarcina domination in anaerobic sequencing batch reactor at short hydraulic retention time.

    PubMed

    Ma, Jingwei; Zhao, Baisuo; Frear, Craig; Zhao, Quanbao; Yu, Liang; Li, Xiujin; Chen, Shulin

    2013-06-01

    The Archaea population of anaerobic sequential batch reactor (ASBR) featuring cycle operations under varying hydraulic retention time (HRT) was evaluated for treating a dilute waste stream. Terminal-Restriction Length Polymorphism and clone libraries for both 16S rRNA gene and mcrA gene were employed to characterize the methanogenic community structure. Results revealed that a Methanosarcina dominated methanogenic community was successfully established when using an ASBR digester at short HRT. It was revealed that both 16S rRNA and mcrA clone library could not provide complete community structure, while combination of two different clone libraries could capture more archaea diversity. Thermodynamic calculations confirmed a preference for the observed population structure. The results both experimentally and theoretically confirmed that Methanosarcina dominance emphasizing ASBR's important role in treating low strength wastewater as Methanosarcina will be more adept at overcoming temperature and shock loadings experienced with treating this type of wastewater.

  14. Photoacoustic detection of blood in dental pulp by using short-time Fourier transform

    NASA Astrophysics Data System (ADS)

    Yamada, Azusa; Kakino, Satoko; Matsuura, Yuji

    2016-03-01

    A method based on photoacoustic analysis is proposed to diagnose dental pulp vitality. Photoacoustic analysis enables to get signal from deeper tissues than other optical analyses and therefore, signal detection from root canal of thick dental tissues such as molar teeth is expected. As a light source for excitation of photoacoustic waves, a microchip Q-switched YAG laser with a wavelength of 1064 nm was used and owing to large penetration depth of the near infrared laser, photoacoustic signals from dental root were successfully obtained. It was found that the photoacoustic signals from the teeth containing hemoglobin solution in the pulp cavity provide vibration in high frequency region. It was also shown that the intensities of the high frequency component have correlation with the hemoglobin concentration of solution. We applied short-time Fourier transform for evaluation of photoacoustic signals and this analysis clearly showed photoacoustic signals from dental root.

  15. Atmospheric Effects Detection By Short Baseline Processing In RADARSTAT Time Series Over Manaus City, Amazon Region

    NASA Astrophysics Data System (ADS)

    Ramos, Fernanda Ledo G.; Nico, Giovanni

    2012-01-01

    In this work we present an analysis of RADARSAT- 1 and RADARSAT-2 times series acquired from 2006 to 2010 aiming to recognize the presence of atmospheric artefacts in the interferometric phase. The dataset was interferometrically processed using a short-baseline strategy, i.e. all interferometric pairs characterized by the shortest temporal baselines were identified. In this dataset the temporal baseline corresponds to the shortest temporal baseline of 24 days which can be achieved using the Radarsat mission. Interferometric phase was compared to estimates of the atmospheric artefacts obtained from the available measurements of the atmospheric parameters (air temperature, pressure, relative humidity, wind speed and direction, precipitations) over the studied area provided by the Brazilian Aeronautic Center of Meteorology.

  16. Transient polar motions and the nature of the asthenosphere for short time scales

    NASA Technical Reports Server (NTRS)

    Boschi, E.; Sabadini, R.; Yuen, D. A.

    1985-01-01

    A uniformly valid mathematical formalism is developed to study the secular motions of the rotational axis of a layered viscoelastic earth due to seismic excitation. The changes required for implementing the formulation within the framework of the faulting problem. The rationale of adopting the chosen nrheological model, which contains a low-viscosity zone beneath the lithosphere and is based on linear Maxell constitutive relationship, is discussed. The impact of this low-viscosity channel on thhe two families of relaxation time, governing both isostatic readjustment and rotational processes, is considered. It is found that the polar motions depend sensitively on the viscosity structure of the asthenosphere and not at all on the underlying mantle. A gloal low-velocity zone with short-term asthenospheric viscosities less than about 5 x 10 to the 18th Pa-s and widths greater than 50 km is ruled out.

  17. Monte Carlo simulations of the short time dynamics of a first-order irreversible phase transition

    NASA Astrophysics Data System (ADS)

    Albano, Ezequiel V.

    2001-09-01

    The ZGB model (Ziff-Gulari-Barshad, Phys. Rev. Lett. 56 (1986) 2553) for the catalytic oxidation of carbon monoxide has a single parameter given by the normalized partial pressure of CO molecules ( PCO). For PCO⩾ PCOCoex≃0.52583 the surface of the catalyst becomes irreversibly covered by CO molecules and the system cannot escape from this state. However, for PCO slightly below PCOCoex the system reaches an active stationary state. So, just at PCOCoex a sharp first-order irreversible phase transition is observed. It is shown that a study of the short time dynamics of the ZGB model allows to obtain a fairly accurate evaluation of the upper spinodal point given by PCOUsp≃0.52675(5). This figure is in excellent agreement with extensive simulations performed using the constant coverage ensemble.

  18. Food Quality Improvement of Soy Milk Made from Short-Time Germinated Soybeans.

    PubMed

    Jiang, Susu; Cai, Weixi; Xu, Baojun

    2013-05-21

    The objectives of this study were to develop soy milk with improved food quality and to enhance the functional attributes by incorporating short-time germination into the processing. Changes in trypsin inhibitor activity (TIA), phytic acid content and total phenolic content (TPC) in soy milk produced from soybeans germinated within 72 h were investigated to determine the optimum germination condition. Results from the present research showed significant (p < 0.05) improvement of TPC in cooked germinated soybean milk, while both the TIA and phytic acid content were decreased significantly (p < 0.05). In the subsequent evaluation on the quality attributes under the optimum germination condition, soy milk made from 28 h-germinated soybeans presented enhanced nutritional value and comparable physicochemical properties to conventional soy milk. The current approach provides a feasible and convenient way for soy-based product innovation in both household and industrial settings.

  19. Effect of market factors on the short-time pricing of stock-exchange metals

    NASA Astrophysics Data System (ADS)

    Bogdanov, S. V.; Shevelev, I. M.; Chernyi, S. A.

    2016-12-01

    The open trade on the world market is estimated using information of one-day exchange prices of nonferrous and precious metals, oil, reduced crude, and gasoline and the main world stock indices in the time period from January 1, 2009 to December 31, 2015. It is found that the short-term changes in the prices of nonferrous metals are determined by the prices on the metal market. The changes in the prices of energy carriers and the stock trade on the stock market weakly influence the pricing of nonferrous and precious metals. The prices of metals depend on the situation during trade on commodity exchanges, and the stock market indirectly influences the exchange prices of metals through changes in the share prices of the companies that produce copper, aluminum, and zinc.

  20. Spinodals and critical point using short-time dynamics for a simple model of liquid.

    PubMed

    Loscar, Ernesto S; Ferrara, C Gastón; Grigera, Tomás S

    2016-04-07

    We have applied the short-time dynamics method to the gas-liquid transition to detect the supercooled gas instability (gas spinodal) and the superheated liquid instability (liquid spinodal). Using Monte Carlo simulation, we have obtained the two spinodals for a wide range of pressure in sub-critical and critical conditions and estimated the critical temperature and pressure. Our method is faster than previous approaches and allows studying spinodals without needing equilibration of the system in the metastable region. It is thus free of the extrapolation problems present in other methods, and in principle could be applied to systems such as glass-forming liquids, where equilibration is very difficult even far from the spinodal. We have also done molecular dynamics simulations, where we find the method again able to detect the both spinodals. Our results are compared with different previous results in the literature and show a good agreement.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Short time administration of antirheumatic drugs - Methotrexate as a strong inhibitor of osteoblast's proliferation in vitro

    PubMed Central

    2012-01-01

    Introduction Due to increasing use of disease modifying antirheumatic drugs (DMARDs) as first line therapy in rheumatic diseases, dental and maxillofacial practitioner should be aware of drug related adverse events. Especially effects on bone-metabolism and its cells are discussed controversially. Therefore we investigate the in vitro effect of short time administration of low dose methotrexate (MTX) on osteoblasts as essential part of bone remodelling cells. Methods Primary bovine osteoblasts (OBs) were incubated with various concentrations of MTX, related to tissue concentrations, over a period of fourteen days by using a previously established standard protocol. The effect on cell proliferation as well as mitochondrial activity was assessed by using 3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyltetrazolium bromide (MTT) assay, imaging and counting of living cells. Additionally, immunostaining of extracellular matrix proteins was used to survey osteogenic differentiation. Results All methods indicate a strong inhibition of osteoblast`s proliferation by short time administration of low dose MTX within therapeutically relevant concentrations of 1 to 1000nM, without affecting cell differentiation of middle-stage differentiated OBs in general. More over a significant decrease of cell numbers and mitochondrial activity was found at these MTX concentrations. The most sensitive method seems to be the MTT-assay. MTX-concentration of 0,01nM and concentrations below had no inhibitory effects anymore. Conclusion Even low dose methotrexate acts as a potent inhibitor of osteoblast’s proliferation and mitochondrial metabolism in vitro, without affecting main differentiation of pre-differentiated osteoblasts. These results suggest possible negative effects of DMARDs concerning bone healing and for example osseointegration of dental implants. Especially the specifics of the jaw bone with its high vascularisation and physiological high tissue metabolism, suggests possible negative

  3. Obtaining a male circumcision prevalence rate of 80% among adults in a short time

    PubMed Central

    Marshall, Esaie; Rain-Taljaard, Reathe; Tsepe, Motlalepule; Monkwe, Cornelius; Taljaard, Dirk; Hlatswayo, Florence; Xaba, Dumazile; Molomo, Tebogo; Lissouba, Pascale; Puren, Adrian; Auvert, Bertran

    2017-01-01

    Abstract World Health Organization recommends a target for the male circumcision prevalence rate of 80%. This rate will have a substantial impact on the human immunodeficiency virus-acquired immunodeficiency syndrome epidemic in Eastern and Southern Africa. The objective of the study was to assess whether an innovative intervention can lead to an increased voluntary male medical circumcision (VMMC) uptake among adults in a short time. This prospective observational study of a demand generation intervention was conducted in the township of Orange Farm (South Africa) in August to November 2015. In this community male circumcision prevalence rate among adults was stable between 2010 and 2015 at 55% and 57%, despite regular VMMC campaigns at community level and the presence of a VMMC clinic that offered free VMMC. The intervention took place in a random sample of 981 households where 522 men aged 18 to 49 years accepted to participate in the study. Among the 226 uncircumcised men, 212 accepted to be enrolled in the intervention study. A personal male circumcision adviser trained in interpersonal communication skills was assigned to each uncircumcised participant. The male circumcision advisers were trained to explain the risks and benefits of VMMC, and to discuss 24 possible reasons given by men for not being circumcised. Participants were then followed for 9 weeks. Each participant had a maximum of 3 motivational interviews at home. Participants who decided to be circumcised received financial compensation for their time equivalent to 2.5 days of work at the minimum South African salary rate. Among the 212 uncircumcised men enrolled in the intervention, 69.8% (148/212; 95% confidence interval [CI]; 63.4%–75.7%) agreed to be circumcised, which defines the uptake of the intervention. The male circumcision prevalence rate of the sample increased from 56.7% (296/522) to 81.4% (425/522; 77.9%–84.6%), P < 0.001, corresponding to a relative increase of 43.6% (95% CI

  4. Laser-induced short time scale thermal chemistry of perfluoropolyether lubricant films

    SciTech Connect

    Heller, J.; Mate, C.J.; Poon, C.C.; Tam, A.C.

    1999-11-09

    The authors investigate the effect of heating a perfluoropolyether lubricant film in a localized area for relatively short time periods using laser irradiation versus conventional oven heating. These experiments help provide understanding on how flash temperatures generated at frictional contacts affect the thermal chemistry of lubricant films. In these experiments, a CO{sub 2} laser heats a 50 {micro}m wide area of a silicon wafer for time periods ranging from 0.1 to 60 s. The surface temperature within the heated area (up to 280 C in these experiments) is monitored with a second laser by measuring the change in reflectivity near the center of the heated area. A major difference observed for laser heating compared to oven heating is that the effective evaporation rate is orders of magnitude higher for laser heating. If the lubricant film is heated for sufficiently long enough time at high temperatures, the authors are able to observe thermal bonding of the lubricant via its alcohol end groups to the silicon oxide surface, followed by thermal decomposition of the lubricant molecules. After laser heating, the authors are able to observe the diffusion of lubricant back into the localized heated area using a combination of optical microscopy and imaging ellipsometry.

  5. Complexity signatures for short time scales in the atmosphere above Adventdalen, Svalbard

    NASA Astrophysics Data System (ADS)

    Hall, C. M.

    2014-01-01

    Atmospheric parameters from the troposphere above Adventdalen, Svalbard, 78°N, 16°E, are examined for signatures of complexity in their respective stochastic components over time scales from ~1 h to 1 year. Several approaches are used, all of which can estimate values of the generalized Hurst exponent, α, which can in turn be compared with each other and with similar independent characterizations, usually via the classic Hurst exponent, H, obtained from location-specific and globally averaged time series. For tropopause altitude, the stochastic component exhibits the signature of a persistent fractional Gaussian noise (fGn) with α ≈ 0.75. For surface air temperature, the indications are for fractional Brownian motion (fBm) with α ≈ 1.4. Using recent high time-resolution data from a single high-latitude location, this identification of fBm is relevant for short-term memory as opposed to findings from many other studies addressing possible long-term memory, which demonstrate fGn with α = H ≈ 0.7. Furthermore, the lack of similarity between the results for surface air temperature and tropopause altitude suggests that different underlying processes are responsible for stochastic variability.

  6. Cisplatin Concentrations in Long and Short Duration Infusion: Implications for the Optimal Time of Radiation Delivery

    PubMed Central

    Mathew, Binu Susan; Das, Saikat; Isaiah, Rajesh; John, Subashini; Prabha, Ratna; Fleming, Denise Helen

    2016-01-01

    Introduction Cisplatin has radiosensitizing properties and the best sensitization to radiotherapy occurs with a higher plasma concentration of cisplatin. To our knowledge the optimal time sequence between chemotherapy and administration of radiation therapy, to obtain maximum effect from concurrent chemoradiation is unclear. Aim The aim of this study was to measure the two cisplatin infusion regimens in order to determine the total and free cisplatin post infusion concentration changes over time. These changes may have clinical implications on the optimum time of administration of post infusion radiation therapy. Materials and Methods Two cohorts of patients were recruited and both, total and free plasma concentration of cisplatin following long and short durations of intravenous infusion was determined. Blood samples were collected at 0.5, 1, 1.5, 2, 3 and 5 hours from the start of the infusion in the 1hour infusion group and at 2, 3, 3.5, 4, 6 and 24 hours from the start of the infusion, in the 3 hour infusion group. Total and free cisplatin concentrations were measured using a validated HPLC-UV method. Results The highest concentration of total and free cisplatin was achieved at the end of the infusion in both regimens. Total cisplatin concentration declined 30 minutes after the end of infusion in both the groups. After 1hour of discontinuing cisplatin, the free cisplatin concentration also declined significantly. Conclusion We conclude that radiation should be administered within 30 minutes of completion of the infusion irrespective of the duration of infusion. PMID:27630935

  7. SHORT DISSIPATION TIMES OF PROTO-PLANETARY DISKS: AN ARTIFACT OF SELECTION EFFECTS?

    SciTech Connect

    Pfalzner, Susanne; Steinhausen, Manuel; Menten, Karl

    2014-10-01

    The frequency of disks around young stars, a key parameter for understanding planet formation, is most readily determined in young stellar clusters where many relatively coeval stars are located in close proximity. Observational studies seem to show that the disk frequency decreases rapidly with cluster age with <10% of cluster stars retaining their disks for longer than 2-6 Myr. Given that at least half of all stars in the field seem to harbor one or more planets, this would imply extremely fast disk dispersal and rapid planet growth. Here we question the validity of this constraint by demonstrating that the short disk dissipation times inferred to date might have been heavily underestimated by selection effects. Critically, for ages >3 Myr only stars that originally populated the densest areas of very populous clusters, which are prone to disk erosion, are actually considered. This tiny sample may not be representative of the majority of stars. In fact, the higher disk fractions in co-moving groups indicate that it is likely that over 30% of all field stars retain their disks well beyond 10 Myr, leaving ample time for planet growth. Equally, our solar system, with a likely formation time >10 Myr, need no longer be an exception but in fact typical of planetary systems.

  8. Time-resolved measurements of short-wavelength fluorescence from x-ray-excited ions.

    PubMed

    Kapteyn, H C; Murnane, M M; Falcone, R W

    1987-09-01

    We demonstrate a novel technique for time-resolved spectroscopic studies of highly excited ions. The technique uses a laser-produced plasma as a short-pulse, soft-x-ray light source with a high repetition rate. A Nd:YAG laser with a pulse duration of 90 psec, a pulse energy of 70 microJ, and repetition rate of 10(4) pulses per second is focused onto a rotating metal target. Soft x rays from the resulting plasma photoionize a gas surrounding the target, and fluorescence from the gas is detected by using a spectrometer and a high-speed photodetector. Using the technique of time-correlated photon counting, we determined the radiative lifetime and collisional quenching rate of the Xe III 5s(0)5p(6)(1)S(0) state by observing its fluorescence at 108.9 nm. A time resolution of better than 400 psec was obtained. We also measured relative Auger decay yields of a core hole state in xenon using a higher-energy laser-produced plasma light source at a lower repetition rate.

  9. Real-time monitoring and short-term forecasting of drought in Norway

    NASA Astrophysics Data System (ADS)

    Kwok Wong, Wai; Hisdal, Hege

    2013-04-01

    Drought is considered to be one of the most costly natural disasters. Drought monitoring and forecasting are thus important for sound water management. In this study hydrological drought characteristics applicable for real-time monitoring and short-term forecasting of drought in Norway were developed. A spatially distributed hydrological model (HBV) implemented in a Web-based GIS framework provides a platform for drought analyses and visualizations. A number of national drought maps can be produced, which is a simple and effective way to communicate drought conditions to decision makers and the public. The HBV model is driven by precipitation and air temperature data. On a daily time step it calculates the water balance for 1 x 1 km2 grid cells characterized by their elevation and land use. Drought duration and areal drought coverage for runoff and subsurface storage (sum of soil moisture and groundwater) were derived. The threshold level method was used to specify drought conditions on a grid cell basis. The daily 10th percentile thresholds were derived from seven-day windows centered on that calendar day from the reference period 1981-2010 (threshold not exceeded 10% of the time). Each individual grid cell was examined to determine if it was below its respective threshold level. Daily drought-stricken areas can then be easily identified when visualized on a map. The drought duration can also be tracked and calculated by a retrospective analysis. Real-time observations from synoptic stations interpolated to a regular grid of 1 km resolution constituted the forcing data for the current situation. 9-day meteorological forecasts were used as input to the HBV model to obtain short-term hydrological drought forecasts. Downscaled precipitation and temperature fields from two different atmospheric models were applied. The first two days of the forecast period adopted the forecasts from Unified Model (UM4) while the following seven days were based on the 9-day forecasts

  10. Long and short time variations of the Na/K ratio in the exosphere of Mercury.

    NASA Astrophysics Data System (ADS)

    Mura, Alessandro; Lammer, Helmut; Wurz, Peter; Orsini, Stefano; Milillo, Anna; Mangano, Valeria; Lichtenegger, Herbert; Scherf, Manuel; Khodachenko, Maxim; Pfleger, Martin

    2014-05-01

    Here we present the results of our model for the short-time and yearly variations of the Sodium and Potassium exosphere of Mercury. Such surface-bounded exosphere is produced by release processes occurring at the planetary surface, such as ion sputtering, thermal- or photon-stimulated desorption. The amount of surface Sodium or Potassium that is available for release, however, is limited. Those release processes deplete the surface in Na and K, which is continuously refilled by diffusion from the interior of regolith grains or by chemical sputtering. Ejected particles may either escape the gravity field, assisted by the radiation pressure acceleration, or be photoionized, or fall back onto the surface. Falling particles will stick to the surface. A Montecarlo model, simulating all these processes, is used to obtain the exosphere densities and the Na/K ratio, taking into account the planet's orbit and rotation speed. The influence of variations of the solar wind precipitation (i.e., CMEs) is also included. We compare this model with either ground- and space-based observations of the exosphere and tail to evaluate the effectiveness of each source process. We find that including a source process which effectiveness is proportional to the precipitation of solar wind protons, is necessary to explain most of the available observations in both qualitative and quantitative way. We find that, to reproduce dawn-dusk asymmetries, we need to include the rotation of Mercury's surface in the model. After finding the correct model parameter by calibrating the model with observation, we simulate the short-term and yearly variations of Na/K.

  11. SHORT GAMMA-RAY BURSTS IN THE ''TIME-REVERSAL'' SCENARIO

    SciTech Connect

    Ciolfi, Riccardo; Siegel, Daniel M. E-mail: daniel.siegel@aei.mpg.de

    2015-01-10

    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 ∼10{sup 2}-10{sup 5} s, suggesting continuous energy injection from a long-lived central engine, which is incompatible with the short (≲ 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 ∼10{sup 5} s, compatible with observations. The success of this fundamental test makes this ''time-reversal'' scenario an attractive alternative to current SGRB models.

  12. Twin Signature Schemes, Revisited

    NASA Astrophysics Data System (ADS)

    Schäge, Sven

    In this paper, we revisit the twin signature scheme by Naccache, Pointcheval and Stern from CCS 2001 that is secure under the Strong RSA (SRSA) assumption and improve its efficiency in several ways. First, we present a new twin signature scheme that is based on the Strong Diffie-Hellman (SDH) assumption in bilinear groups and allows for very short signatures and key material. A big advantage of this scheme is that, in contrast to the original scheme, it does not require a computationally expensive function for mapping messages to primes. We prove this new scheme secure under adaptive chosen message attacks. Second, we present a modification that allows to significantly increase efficiency when signing long messages. This construction uses collision-resistant hash functions as its basis. As a result, our improvements make the signature length independent of the message size. Our construction deviates from the standard hash-and-sign approach in which the hash value of the message is signed in place of the message itself. We show that in the case of twin signatures, one can exploit the properties of the hash function as an integral part of the signature scheme. This improvement can be applied to both the SRSA based and SDH based twin signature scheme.

  13. R -matrix-incorporating-time method for H2+ in short and intense laser fields

    NASA Astrophysics Data System (ADS)

    Ó Broin, Cathal; Nikolopoulos, L. A. A.

    2015-12-01

    In this work we develop an approach for a molecular hydrogen ion (H2+ ) in the Born-Oppenheimer approximation while exposed to intense short-pulse radiation. Our starting point is the R -matrix-incorporating-time formulation for atomic hydrogen [L. A. A. Nikolopoulos et al., Phys. Rev. A 78, 063420 (2008), 10.1103/PhysRevA.78.063420], which has proven to be successful at treating multielectron atomic systems efficiently and with a high accuracy [L. R. Moore et al., J. Mod. Opt. 58, 1132 (2011), 10.1080/09500340.2011.559315]. The present study on H2+ is performed with the similar objective of developing an ab initio method for solving the time-dependent Schrödinger equation for multielectron diatomic molecules exposed to an external time-dependent potential field. The theoretical formulation is developed in detail for the molecular hydrogen ion where all the multielectron and internuclei complications are absent. As in the atomic case, the configuration space of the electron's coordinates is separated artificially over two regions: the inner (I) and outer (II) regions. In region I the time-dependent wave function is expanded on the eigenstate basis corresponding to the molecule's Hamiltonian augmented by Bloch operators, while in region II a grid representation is used. We demonstrate the independence of our results from the introduced artificial boundary surface by calculating observables that are directly accessed experimentally and also by showing that gauge-dependent quantities are also invariant with the region I box size. We also compare our results with other theoretical works and emphasize cases where basis-set approaches are currently very computationally expensive or intractable in terms of computational resources.

  14. Short-time electrical effects during volcanic eruption: Experiments and field measurements

    NASA Astrophysics Data System (ADS)

    Büttner, Ralf; Zimanowski, Bernd; Röder, Helmut

    2000-02-01

    Laboratory experiments on the fragmentation and expansion of magmatic melt have been performed using remelted volcanic rock at magmatic temperatures as magma simulant. A specially designed dc amplifier in combination with high speed data recording was used to detect short-time electrostatic field effects related to the fragmentation and expansion history of the experimental system, as documented by simultaneous force and pressure recording, as well as by high-speed cinematography. It was found that (1) the voltage-time ratio of electrostatic field gradients (100 to 104 V/s) reflects different physical mechanisms of fragmentation and expansion and (2) the maximum voltage measured in 1 m distance (-0.1 to -180 V) can be correlated with the intensity of the respective processes. Based on these experimental results, a field method was developed and tested at Stromboli volcano in Italy. A 0.8 m rod antenna was used to detect the dc voltage against local ground (i.e., the electrostatic field gradient), at a distance of 60 to 260 m from the respective vent. Upwind position of the detection site was chosen to prevent interference caused by contact of charged ash particles with the antenna. A standard 8 Hz geophone was used to detect the accompanying seismicity. Three types of volcanic activity occurred during the surveillance operation; two of these could be clearly related to specific electrical and seismical signals. A typical delay time was found between the electrical and the seismical signal, corresponding to the seismic velocity within the crater deposits. Using a simple first-order electrostatic model, the field measurements were recalibrated to the laboratory scale. Comparison of field and laboratory data at first approximation revealed striking similarities, thus encouraging the further development of this technique for real-time surveillance operation at active volcanoes.

  15. Multifractals embedded in short time series: An unbiased estimation of probability moment

    NASA Astrophysics Data System (ADS)

    Qiu, Lu; Yang, Tianguang; Yin, Yanhua; Gu, Changgui; Yang, Huijie

    2016-12-01

    An exact estimation of probability moments is the base for several essential concepts, such as the multifractals, the Tsallis entropy, and the transfer entropy. By means of approximation theory we propose a new method called factorial-moment-based estimation of probability moments. Theoretical prediction and computational results show that it can provide us an unbiased estimation of the probability moments of continuous order. Calculations on probability redistribution model verify that it can extract exactly multifractal behaviors from several hundred recordings. Its powerfulness in monitoring evolution of scaling behaviors is exemplified by two empirical cases, i.e., the gait time series for fast, normal, and slow trials of a healthy volunteer, and the closing price series for Shanghai stock market. By using short time series with several hundred lengths, a comparison with the well-established tools displays significant advantages of its performance over the other methods. The factorial-moment-based estimation can evaluate correctly the scaling behaviors in a scale range about three generations wider than the multifractal detrended fluctuation analysis and the basic estimation. The estimation of partition function given by the wavelet transform modulus maxima has unacceptable fluctuations. Besides the scaling invariance focused in the present paper, the proposed factorial moment of continuous order can find its various uses, such as finding nonextensive behaviors of a complex system and reconstructing the causality relationship network between elements of a complex system.

  16. Rapid growth, early maturation and short generation time in African annual fishes

    PubMed Central

    2013-01-01

    Background Extreme environmental conditions can give rise to extreme adaptations. We document growth, sexual maturation and fecundity in two species of African annual fish inhabiting temporary savanna pools. Results Nothobranchius kadleci started to reproduce at the age of 17 days and size of 31 mm and Nothobranchius furzeri at 18 days and 32 mm. All four study populations demonstrated rapid growth rates of up to 2.72 mm/day (23.4% of their total length). Both species may produce diapausing embryos or embryos that are able to hatch in as few as 15 days, resulting in a minimum generation time as short as only one month. Incubation on the surface of damp peat moss results in high embryo survival (73%) and a high proportion of rapidly developing embryos (58%) that skip diapauses and hatch in less than 30 days. We further demonstrated that rapid growth and maturation do not compromise subsequent fecundity. Conclusions Our data suggest that both species have the most rapid sexual maturation and minimum generation time of any vertebrate species, and that rapid maturity does not involve paedogenesis. PMID:24007640

  17. Timing of introduction of complementary food: short- and long-term health consequences.

    PubMed

    Przyrembel, Hildegard

    2012-01-01

    Complementary food is needed when breast milk (or infant formula) alone is no longer sufficient for both nutritional and developmental reasons. The timing of its introduction, therefore, is an individual decision, although 6 months of exclusive breastfeeding can be recommended for most healthy term infants. The new foods are intended to 'complement' ongoing breastfeeding with those dietary items whose intake has become marginal or insufficient. Both breastfeeding and complementary feeding can have direct or later consequences on health. The evaluation of consequences of both early and late introduction of complementary food can neither disregard the effect of breastfeeding compared to formula feeding nor the composition or quality of the complementary food. Possible short-term health effects concern growth velocity and infections, and possible long-term effects may relate to atopic diseases, type 1 and 2 diabetes, obesity and neuromuscular development. On the basis of the currently available evidence, it is impossible to exactly determine the age when risks related to the start of complementary feeding are lowest or highest for most of these effects, with the possible exception of infections and early growth velocity. The present knowledge on undesirable health effects, however, is mainly based on observational studies, and although some mechanisms have been proposed, further prospective studies have to clarify these unsolved issues. Even less evidence on the consequences of the timing of complementary food introduction is available for formula-fed infants.

  18. Two Machine Learning Approaches for Short-Term Wind Speed Time-Series Prediction.

    PubMed

    Ak, Ronay; Fink, Olga; Zio, Enrico

    2016-08-01

    The increasing liberalization of European electricity markets, the growing proportion of intermittent renewable energy being fed into the energy grids, and also new challenges in the patterns of energy consumption (such as electric mobility) require flexible and intelligent power grids capable of providing efficient, reliable, economical, and sustainable energy production and distribution. From the supplier side, particularly, the integration of renewable energy sources (e.g., wind and solar) into the grid imposes an engineering and economic challenge because of the limited ability to control and dispatch these energy sources due to their intermittent characteristics. Time-series prediction of wind speed for wind power production is a particularly important and challenging task, wherein prediction intervals (PIs) are preferable results of the prediction, rather than point estimates, because they provide information on the confidence in the prediction. In this paper, two different machine learning approaches to assess PIs of time-series predictions are considered and compared: 1) multilayer perceptron neural networks trained with a multiobjective genetic algorithm and 2) extreme learning machines combined with the nearest neighbors approach. The proposed approaches are applied for short-term wind speed prediction from a real data set of hourly wind speed measurements for the region of Regina in Saskatchewan, Canada. Both approaches demonstrate good prediction precision and provide complementary advantages with respect to different evaluation criteria.

  19. 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.

  20. Suborbital Asteroid Intercept and Fragmentation for Very Short Warning Time Scenarios

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    Small near-Earth objects (NEOs) 50150 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. However, 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 fictitious 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 NEOwould strike Earth. We also find that more powerful versions of the launch vehicles (e.g., total V 9.511 kms) could intercept incoming NEOs over a day prior to when the NEO would strike Earth, if launched at least several days prior to the time of NEO intercept. Finally, we discuss a number of limiting factors and practicalities that affect whether the notional systems we describe could become feasible.

  1. Revisiting the Impact of Part-Time Work on Adolescent Adjustment: Distinguishing between Selection and Socialization Using Propensity Score Matching

    ERIC Educational Resources Information Center

    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…

  2. Optimizing Coverage and Revisit Time in Sparse Military Satellite Constellations: A Comparison of Traditional Approaches and Genetic Algorithms

    DTIC Science & Technology

    2004-09-01

    2 3. Kepler ....................................................................................... 2 4. Newton...26 Figure 5. SAR Effective Antenna Length [From 12]........................................... 28 Figure 6. SAR/GMTI Composite [From 14...work. 3. Kepler Johann Kepler (1571-1630) determined how to relate mean and true anomalies in the orbit to time in order to predict future

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

    SciTech Connect

    Kong, D. F.; Qu, Z. N.; Guo, Q. L.

    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.

  4. 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

  5. Timing of short-day exposure influences diapause response of western tarnished plant bug

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The western tarnished plant bug, Lygus hesperus, enters adult diapause in response to short photoperiods. However, the instars or stages responsive to the photoperiodic cue are poorly defined. Lygus were reared under short days (10 h) until they were dissected to determine diapause status as 10-d-o...

  6. Estimation of short-time cross-correlation between frequency bands of event related EEG.

    PubMed

    Zygierewicz, J; Mazurkiewicz, J; Durka, P J; Franaszczuk, P J; Crone, N E

    2006-10-30

    Simultaneous variations of the event-related power changes (ERD/ERS) are often observed in a number of frequency bands. ERD/ERS measures are usually based on the relative changes of power in a given single frequency band. Within such an approach one cannot answer questions concerning the mutual relations between the band-power variations observed in different frequency bands. This paper addresses the problem of estimating and assessing the significance of the average cross-correlation between ERD/ERS phenomena occurring in two frequency bands. The cross-correlation function in a natural way also provides estimation of the delay between ERD/ERS in those bands. The proposed method is based on estimating the short-time cross-correlation function between relative changes of power in two selected frequency bands. The cross-correlation function is estimated in each trial separately and then averaged across trials. The significance of those mean cross-correlation functions is evaluated by means of a nonparametric test. The basic properties of the method are presented on simulated signals, and an example application to real EEG and ECoG signals is given.

  7. Generalization of Clausius-Mossotti approximation in application to short-time transport properties of suspensions

    NASA Astrophysics Data System (ADS)

    Makuch, Karol

    2015-10-01

    In 1983, Felderhof, Ford, and Cohen gave microscopic explanation of the famous Clausius-Mossotti formula for the dielectric constant of nonpolar dielectric. They based their considerations on the cluster expansion of the dielectric constant, which relates this macroscopic property with the microscopic characteristics of the system. In this article, we analyze the cluster expansion of Felderhof, Ford, and Cohen by performing its resummation (renormalization). Our analysis leads to the ring expansion for the macroscopic characteristic of the system, which is an expression alternative to the cluster expansion. Using similarity of structures of the cluster expansion and the ring expansion, we generalize (renormalize) the Clausius-Mossotti approximation. We apply our renormalized Clausius-Mossotti approximation to the case of the short-time transport properties of suspensions, calculating the effective viscosity and the hydrodynamic function with the translational self-diffusion and the collective diffusion coefficient. We perform calculations for monodisperse hard-sphere suspensions in equilibrium with volume fraction up to 45 % . To assess the renormalized Clausius-Mossotti approximation, it is compared with numerical simulations and the Beenakker-Mazur method. The results of our renormalized Clausius-Mossotti approximation lead to comparable or much less error (with respect to the numerical simulations) than the Beenakker-Mazur method for the volume fractions below ϕ ≈30 % (apart from a small range of wave vectors in hydrodynamic function). For volume fractions above ϕ ≈30 % , the Beenakker-Mazur method gives in most cases lower error than the renormalized Clausius-Mossotti approximation.

  8. Zipf's law in short-time timbral codings of speech, music, and environmental sound signals.

    PubMed

    Haro, Martín; Serrà, Joan; Herrera, Perfecto; Corral, Alvaro

    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.

  9. 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.

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

    PubMed Central

    Haro, Martín; Serrà, Joan; Herrera, Perfecto; Corral, Álvaro

    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

  11. Java-based framework for processing and displaying short-echo-time magnetic resonance spectroscopy signals.

    PubMed

    De Neuter, B; Luts, J; Vanhamme, L; Lemmerling, P; Van Huffel, S

    2007-02-01

    Magnetic resonance spectroscopy (MRS) can be used to determine in a non-invasive way the concentrations of certain chemical substances, also called metabolites. The spectra of MRS signals contain peaks that correspond to the metabolites of interest. Short-echo-time signals are characterized by heavily overlapping metabolite peaks and require sophisticated processing methods. To be useful in a clinical environment tools are needed that can process those signals in an accurate and fast way. Therefore, we developed novel processing methods and we designed a freely available and open-source framework (http://www.esat.kuleuven.ac.be/sista/members/biomed) in which the processing methods can be integrated. The framework has a set of abstract classes, called hot spots, and its goal is to provide a general structure and determine the control flow of the program. It provides building blocks or components in order to help developers with integrating their methods in the framework via a plug-in system. The framework is designed with the unified modeling language (UML) and implemented in Java. When a developer implements the framework he gets an application that acts like a simple and user-friendly graphical user interface (GUI) for processing MRS data. This article describes in detail the structure and implementation of the framework and the integration of our processing methods in it.

  12. Short T2 contrast with three-dimensional ultrashort echo time imaging

    PubMed Central

    Du, Jiang; Bydder, Mark; Takahashi, Atsushi M.; Carl, Michael; Chung, Christine B.; Bydder, Graeme M.

    2014-01-01

    There is increasing interest in imaging short T2 species which show little or no signal with conventional magnetic resonance (MR) pulse sequences. In this paper, we describe the use of three-dimensional ultrashort echo time (3D UTE) sequences with TEs down to 8 μs for imaging of these species. Image contrast was generated with acquisitions using dual echo 3D UTE with echo subtraction, dual echo 3D UTE with rescaled subtraction, long T2 saturation 3D UTE, long T2 saturation dual echo 3D UTE with echo subtraction, single adiabatic inversion recovery 3D UTE, single adiabatic inversion recovery dual echo 3D UTE with echo subtraction and dual adiabatic inversion recovery 3D UTE. The feasibility of using these approaches was demonstrated in in vitro and in vivo imaging of calcified cartilage, aponeuroses, menisci, tendons, ligaments and cortical bone with a 3-T clinical MR scanner. Signal-to-noise ratios and contrast-to-noise ratios were used to compare the techniques. PMID:21440400

  13. Applying Short-Time Fourier Transform on Groundwater Fluctuation for the Estimation of Regional Groundwater Pumping

    NASA Astrophysics Data System (ADS)

    Chen, Y. W.; Yu, C. H.; Wang, Y.; Chang, L. C.; Chen, Y. C.

    2015-12-01

    For sustainable management of groundwater resource, precise records of regional groundwater pumping is crucial. However, the fact that number of private pumping wells is too huge makes obtaining precise pumping records of each wells become difficult. Because the most significant response of pumping is drawdown and the influence radius of pumping might over several hundred meters, a network of observation wells can be used to sense the regional pumping. Groundwater fluctuations are the synthetic effect of different physical mechanisms include pumping, recharge, tidal effect and others and an analysis of short-time Fourier transform is applied to identified the temporal effects of each mechanisms. Because pumping is a kind of human activity and the most significant frequency of human activity is daily, the temporal amplitude with daily frequency (TADF) is the response of regional pumping in the neighborhood of the observation well and TADF can be a linear indicator of regional groundwater pumping. The proposed method was applied in the Pingtung Plain and the horizontal of analysis period is from 2008 to 2011. The TADF of each observation well can reflect the temporal variation of regional groundwater pumping around the observation well. For the well in coast area, the shape of TADF looks like a sinusoid line with a half year cycle and the peaks of large pumping respectively are during January and July. The peaks of large pumping are mainly caused by fish farms.

  14. The wide-angle equation and its solution through the short-time iterative Lanczos method.

    PubMed

    Campos-Martínez, José; Coalson, Rob D

    2003-03-20

    Properties of the wide-angle equation (WAEQ), a nonparaxial scalar wave equation used to propagate light through media characterized by inhomogeneous refractive-index profiles, are studied. In particular, it is shown that the WAEQ is not equivalent to the more complicated but more fundamental Helmholtz equation (HEQ) when the index of refraction profile depends on the position along the propagation axis. This includes all nonstraight waveguides. To study the quality of the WAEQ approximation, we present a novel method for computing solutions to the WAEQ. This method, based on a short-time iterative Lanczos (SIL) algorithm, can be applied directly to the full three-dimensional case, i.e., systems consisting of the propagation axis coordinate and two transverse coordinates. Furthermore, the SIL method avoids series-expansion procedures (e.g., Padé approximants) and thus convergence problems associated with such procedures. Detailed comparisons of solutions to the HEQ, WAEQ, and the paraxial equation (PEQ) are presented for two cases in which numerically exact solutions to the HEQ can be obtained by independent analysis, namely, (i) propagation in a uniform dielectric medium and (ii) propagation along a straight waveguide that has been tilted at an angle to the propagation axis. The quality of WAEQ and PEQ, compared with exact HEQ results, is investigated. Cases are found for which the WAEQ actually performs worse than the PEQ.

  15. Short time interval for condensation of high-temperature silicates in the solar accretion disk

    PubMed Central

    Luu, Tu-Han; Young, Edward D.; Gounelle, Matthieu; Chaussidon, Marc

    2015-01-01

    Chondritic meteorites are made of primitive components that record the first steps of formation of solids in our Solar System. Chondrules are the major component of chondrites, yet little is known about their formation mechanisms and history within the solar protoplanetary disk (SPD). We use the reconstructed concentrations of short-lived 26Al in chondrules to constrain the timing of formation of their precursors in the SPD. High-precision bulk magnesium isotopic measurements of 14 chondrules from the Allende chondrite define a 26Al isochron with 26Al/27Al = 1.2(±0.2) × 10−5 for this subset of Allende chondrules. This can be considered to be the minimum bulk chondrule 26Al isochron because all chondrules analyzed so far with high precision (∼50 chondrules from CV and ordinary chondrites) have an inferred minimum bulk initial (26Al/27Al) ≥ 1.2 × 10−5. In addition, mineral 26Al isochrons determined on the same chondrules show that their formation (i.e., fusion of their precursors by energetic events) took place from 0 Myr to ∼2 Myr after the formation of their precursors, thus showing in some cases a clear decoupling in time between the two events. The finding of a minimum bulk chondrule 26Al isochron is used to constrain the astrophysical settings for chondrule formation. Either the temperature of the condensation zone dropped below the condensation temperature of chondrule precursors at ∼1.5 My after the start of the Solar System or the transport of precursors from the condensation zone to potential storage sites stopped after 1.5 My, possibly due to a drop in the disk accretion rate. PMID:25605942

  16. Short time interval for condensation of high-temperature silicates in the solar accretion disk.

    PubMed

    Luu, Tu-Han; Young, Edward D; Gounelle, Matthieu; Chaussidon, Marc

    2015-02-03

    Chondritic meteorites are made of primitive components that record the first steps of formation of solids in our Solar System. Chondrules are the major component of chondrites, yet little is known about their formation mechanisms and history within the solar protoplanetary disk (SPD). We use the reconstructed concentrations of short-lived (26)Al in chondrules to constrain the timing of formation of their precursors in the SPD. High-precision bulk magnesium isotopic measurements of 14 chondrules from the Allende chondrite define a (26)Al isochron with (26)Al/(27)Al = 1.2(±0.2) × 10(-5) for this subset of Allende chondrules. This can be considered to be the minimum bulk chondrule (26)Al isochron because all chondrules analyzed so far with high precision (∼50 chondrules from CV and ordinary chondrites) have an inferred minimum bulk initial ((26)Al/(27)Al) ≥ 1.2 × 10(-5). In addition, mineral (26)Al isochrons determined on the same chondrules show that their formation (i.e., fusion of their precursors by energetic events) took place from 0 Myr to ∼2 Myr after the formation of their precursors, thus showing in some cases a clear decoupling in time between the two events. The finding of a minimum bulk chondrule (26)Al isochron is used to constrain the astrophysical settings for chondrule formation. Either the temperature of the condensation zone dropped below the condensation temperature of chondrule precursors at ∼1.5 My after the start of the Solar System or the transport of precursors from the condensation zone to potential storage sites stopped after 1.5 My, possibly due to a drop in the disk accretion rate.

  17. 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.

  18. Gradient pattern analysis of short nonstationary time series: an application to Lagrangian data from satellite tracked drifters

    NASA Astrophysics Data System (ADS)

    Assireu, A. T.; Rosa, R. R.; Vijaykumar, N. L.; Lorenzzetti, J. A.; Rempel, E. L.; Ramos, F. M.; Abreu Sá, L. D.; Bolzan, M. J. A.; Zanandrea, A.

    2002-08-01

    Based on the gradient pattern analysis (GPA) technique we introduce a new methodology for analyzing short nonstationary time series. Using the asymmetric amplitude fragmentation (AAF) operator from GPA we analyze Lagrangian data observed as velocity time series for ocean flow. The results show that quasi-periodic, chaotic and turbulent regimes can be well characterized by means of this new geometrical approach.

  19. Time-Based Loss in Visual Short-Term Memory Is from Trace Decay, Not Temporal Distinctiveness

    ERIC Educational Resources Information Center

    Ricker, Timothy J.; Spiegel, Lauren R.; Cowan, Nelson

    2014-01-01

    There is no consensus as to why forgetting occurs in short-term memory tasks. In past work, we have shown that forgetting occurs with the passage of time, but there are 2 classes of theories that can explain this effect. In the present work, we investigate the reason for time-based forgetting by contrasting the predictions of temporal…

  20. Revisiting Mr. Tall and Mr. Short

    ERIC Educational Resources Information Center

    Riehl, Suzanne M.; Steinthorsdottir, Olof Bjorg

    2014-01-01

    Ratio, rate, and proportion are central ideas in the Common Core State Standards (CCSS) for middle-grades mathematics (CCSSI 2010). These ideas closely connect to themes in earlier grades (pattern building, multiplicative reasoning, rational number concepts) and are the foundation for understanding linear functions as well as many high school…

  1. 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.

  2. Production altitude and time delays of the terrestrial gamma flashes: Revisiting the Burst and Transient Source Experiment spectra

    NASA Astrophysics Data System (ADS)

    Østgaard, N.; Gjesteland, T.; Stadsnes, J.; Connell, P. H.; Carlson, B.

    2008-02-01

    On the basis of the RHESSI results it has been suggested that terrestrial gamma flashes (TGFs) are produced at very low altitudes. On the other hand some of the Burst and Transient Source Experiment (BATSE) spectra show unabsorbed fluxes of X rays in the 25-50 keV energy range, indicating a higher production altitude. To investigate this, we have developed a Monte Carlo code for X-ray propagation through the atmosphere. The most important features seen in the modeled spectra are (1) a low-energy cutoff which moves to lower energies as TGFs are produced at higher altitudes, (2) a high-energy cutoff which moves to lower energies as TGFs are observed at larger zenith angles, and (3) time delays are observed for TGFs produced at <=20 km (and some at 30 km) altitude when observed at larger zenith angle than the half-angle defining the initial isotropic X-ray beam. This is a pure Compton effect. The model results and an optimization procedure are used to estimate production altitudes of the BATSE TGFs. The main findings are (1) half or more of the BATSE TGFs are produced at low altitudes, <=20 km, (2) a significant portion of the BATSE TGFs are produced at higher altitudes, 30 km to 40 km, (3) for the TGFs produced at <=20 km (and some at 30 km) altitudes the dispersion signatures can be explained as a pure Compton effect, and (4) the softening of the BATSE spectra for increasing zenith angles and the time dispersions both indicate that the initial TGF distribution is beamed.

  3. Short-Time Structural Stability of Compressible Vortex Sheets with Surface Tension

    NASA Astrophysics Data System (ADS)

    Stevens, Ben

    2016-11-01

    Assume we start with an initial vortex-sheet configuration which consists of two inviscid fluids with density bounded below flowing smoothly past each other, where a strictly positive fixed coefficient of surface tension produces a surface tension force across the common interface, balanced by the pressure jump. We model the fluids by the compressible Euler equations in three space dimensions with a very general equation of state relating the pressure, entropy and density such that the sound speed is positive. We prove that, for a short time, there exists a unique solution of the equations with the same structure. The mathematical approach consists of introducing a carefully chosen artificial viscosity-type regularisation which allows one to linearise the system so as to obtain a collection of transport equations for the entropy, pressure and curl together with a parabolic-type equation for the velocity which becomes fairly standard after rotating the velocity according to the interface normal. We prove a high order energy estimate for the non-linear equations that is independent of the artificial viscosity parameter which allows us to send it to zero. This approach loosely follows that introduced by Shkoller et al. in the setting of a compressible liquid-vacuum interface. Although already considered by Coutand et al. [10] and Lindblad [17], we also make some brief comments on the case of a compressible liquid-vacuum interface, which is obtained from the vortex sheets problem by replacing one of the fluids by vacuum, where it is possible to obtain a structural stability result even without surface tension.

  4. Variational data assimilation for the optimized ozone initial state and the short-time forecasting

    NASA Astrophysics Data System (ADS)

    Park, Soon-Young; Kim, Dong-Hyeok; Lee, Soon-Hwan; Lee, Hwa Woon

    2016-03-01

    In this study, we apply the four-dimensional variational (4D-Var) data assimilation to optimize initial ozone state and to improve the predictability of air quality. The numerical modeling systems used for simulations of atmospheric condition and chemical formation are the Weather Research and Forecasting (WRF) model and the Community Multiscale Air Quality (CMAQ) model. The study area covers the capital region of South Korea, where the surface measurement sites are relatively evenly distributed. The 4D-Var code previously developed for the CMAQ model is modified to consider background error in matrix form, and various numerical tests are conducted. The results are evaluated with an idealized covariance function for the appropriateness of the modified codes. The background error is then constructed using the NMC method with long-term modeling results, and the characteristics of the spatial correlation scale related to local circulation are analyzed. The background error is applied in the 4D-Var research, and a surface observational assimilation is conducted to optimize the initial concentration of ozone. The statistical results for the 12 h assimilation periods and the 120 observatory sites show a 49.4 % decrease in the root mean squared error (RMSE), and a 59.9 % increase in the index of agreement (IOA). The temporal variation of spatial distribution of the analysis increments indicates that the optimized initial state of ozone concentration is transported to inland areas by the clockwise-rotating local circulation during the assimilation windows. To investigate the predictability of ozone concentration after the assimilation window, a short-time forecasting is carried out. The ratios of the RMSE (root mean squared error) with assimilation versus that without assimilation are 8 and 13 % for the +24 and +12 h, respectively. Such a significant improvement in the forecast accuracy is obtained solely by using the optimized initial state. The potential improvement in

  5. Variational data assimilation for the optimized ozone initial state and the short-time forecasting

    NASA Astrophysics Data System (ADS)

    Park, Soon-Young; Kim, Dong-Hyeok; Lee, Soon-Hwan; Lee, Hwa Woon

    2016-04-01

    In this study, we apply the four-dimensional variational (4D-Var) data assimilation to optimize initial ozone state and to improve the predictability of air quality. The numerical modeling systems used for simulations of atmospheric condition and chemical formation are the Weather Research and Forecasting (WRF) model and the Community Multiscale Air Quality (CMAQ) model . The study area covers the capital region of South Korea, where the surface measurement sites are relatively evenly distributed. The 4D-Var code previously developed for the CMAQ model is modified to consider background error in matrix form, and various numerical tests are conducted. The results are evaluated with an idealized covariance function for the appropriateness of the modified codes. The background error is then constructed using the NMC method with long-term modeling results, and the characteristics of the spatial correlation scale related to local circulation is analyzed. The background error is applied in the 4D-Var research, and a surface observational assimilation is conducted to optimize the initial concentration of ozone. The statistical results for the 12-hour assimilation periods and the 120 observatory sites show a 49.4% decrease in the root mean squred error (RMSE), and a 59.9% increase in the index of agreement (IOA). The temporal variation of spatial distribution of the analysis increments indicates that the optimized initial state of ozone concentration is transported to inland areas by the clockwise-rotating local circulation during the assimilation windows. To investigate the predictability of ozone concentration after the assimilation window, a short-time forecasting is carried out. The ratios of the RMSE with assimilation versus that without assimilation are 8% and 13% for the +24 and +12 hours, respectively. Such a significant improvement in the forecast accuracy is obtained solely by using the optimized initial state. The potential improvement in ozone prediction for

  6. Generalization of Clausius-Mossotti approximation in application to short-time transport properties of suspensions.

    PubMed

    Makuch, Karol

    2015-10-01

    In 1983, Felderhof, Ford, and Cohen gave microscopic explanation of the famous Clausius-Mossotti formula for the dielectric constant of nonpolar dielectric. They based their considerations on the cluster expansion of the dielectric constant, which relates this macroscopic property with the microscopic characteristics of the system. In this article, we analyze the cluster expansion of Felderhof, Ford, and Cohen by performing its resummation (renormalization). Our analysis leads to the ring expansion for the macroscopic characteristic of the system, which is an expression alternative to the cluster expansion. Using similarity of structures of the cluster expansion and the ring expansion, we generalize (renormalize) the Clausius-Mossotti approximation. We apply our renormalized Clausius-Mossotti approximation to the case of the short-time transport properties of suspensions, calculating the effective viscosity and the hydrodynamic function with the translational self-diffusion and the collective diffusion coefficient. We perform calculations for monodisperse hard-sphere suspensions in equilibrium with volume fraction up to 45%. To assess the renormalized Clausius-Mossotti approximation, it is compared with numerical simulations and the Beenakker-Mazur method. The results of our renormalized Clausius-Mossotti approximation lead to comparable or much less error (with respect to the numerical simulations) than the Beenakker-Mazur method for the volume fractions below ϕ≈30% (apart from a small range of wave vectors in hydrodynamic function). For volume fractions above ϕ≈30%, the Beenakker-Mazur method gives in most cases lower error than the renormalized Clausius-Mossotti approximation.

  7. 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…

  8. 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.

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

    PubMed Central

    Payton, Karen L.; Shrestha, Mona

    2013-01-01

    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

  10. Estimating return periods of extreme values from relatively short time series of winds

    NASA Astrophysics Data System (ADS)

    Jonasson, Kristjan; Agustsson, Halfdan; Rognvaldsson, Olafur; Arfeuille, Gilles

    2013-04-01

    An important factor for determining the prospect of individual wind farm sites is the frequency of extreme winds at hub height. Here, extreme winds are defined as the value of the highest 10 minutes averaged wind speed with a 50 year return period, i.e. annual exceeding probability of 2% (Rodrigo, 2010). A frequently applied method to estimate winds in the lowest few hundred meters above ground is to extrapolate observed 10-meter winds logarithmically to higher altitudes. Recent study by Drechsel et al. (2012) showed however that this methodology is not as accurate as interpolating simulated results from the global ECMWF numerical weather prediction (NWP) model to the desired height. Observations of persistent low level jets near Colima in SW-Mexico also show that the logarithmic approach can give highly inaccurate results for some regions (Arfeuille et al., 2012). To address these shortcomings of limited, and/or poorly representative, observations and extrapolations of winds one can use NWP models to dynamically scale down relatively coarse resolution atmospheric analysis. In the case of limited computing resources one has typically to make a compromise between spatial resolution and the duration of the simulated period, both of which can limit the quality of the wind farm siting. A common method to estimate maximum winds is to fit an extreme value distribution (e.g. Gumbel, gev or Pareto) to the maximum values of each year of available data, or the tail of these values. If data are only available for a short period, e.g. 10 or 15 years, then this will give a rather inaccurate estimate. It is possible to deal with this problem by utilizing monthly or weekly maxima, but this introduces new problems: seasonal variation, autocorrelation of neighboring values, and increased discrepancy between data and fitted distribution. We introduce a new method to estimate return periods of extreme values of winds at hub height from relatively short time series of winds, simulated

  11. Dual Inversion Recovery Ultrashort Echo Time (DIR UTE) Imaging: Creating High Contrast for Short-T2 Species

    PubMed Central

    Du, Jiang; Takahashi, Atsushi M.; Bae, Won C.; Chung, Christine B.; Bydder, Graeme M.

    2015-01-01

    Imaging of short-T2 species requires not only a short echo time (TE) but also efficient suppression of long-T2 species in order to maximize the short-T2 contrast and dynamic range. This paper introduces a method of long-T2 suppression using two long adiabatic inversion pulses. The first adiabatic inversion pulse inverts the magnetization of long-T2 water and the second one inverts that of fat. Short-T2 species experience a significant transverse relaxation during the long adiabatic inversion process, and are minimally affected by the inversion pulses. Data acquisition with a short TE of 8 μs starts following a time delay of TI1 for the inverted water magnetization to reach a null point, and a time delay of TI2 for the inverted fat magnetization to reach a null point. The suppression of long-T2 species depends on proper combination of TI1, TI2 and TR. It is insensitive to RF inhomogeneities because of the adiabatic inversion pulses. The feasibility of this dual inversion recovery ultrashort TE (DIR UTE) technique was demonstrated on phantoms, cadaveric specimens and healthy volunteers using a clinical 3T scanner. High image contrast was achieved for the deep radial and calcified layers of articular cartilage, cortical bone and the Achilles tendon. PMID:20099332

  12. Revisiting the Posttherapeutic Cure Criterion in Chagas Disease: Time for New Methods, More Questions, Doubts, and Polemics or Time to Change Old Concepts?

    PubMed Central

    de Lana, Marta; Martins-Filho, Olindo Assis

    2015-01-01

    One of the most relevant issues beyond the effectiveness of etiological treatment of Chagas disease is the lack of consensual/feasible tools to identify and certify the definitive parasitological cure. Several methods of distinct natures (parasitological, serological, and molecular) have been continuously proposed and novel perspectives are currently under investigation. Although the simultaneous use of distinct tests may offer better contributions and advances, it also leads to controversies of interpretation, with lack of mutual consent of cure criterion amongst researchers and physicians. In fact, when distinct host compartments (blood/tissues) are evaluated and explored, novel questions may arise due to the nature and sensitivity limit of each test. This short analytical review intends to present a chronological and critical overview and discuss the state-of-the-art distinct devices available for posttherapeutic cure assessment in Chagas disease, their contributions, meanings, and interpretation, aiming to point out the major gaps and propose novel insight for future perspectives of posttherapeutic management of Chagas disease patients. PMID:26583124

  13. Short Time Lyapounov Indicators in the Case of a Sun-Jupiter-Saturn-Asteroid System

    NASA Astrophysics Data System (ADS)

    Balla, R. F.; Sandor, Zs.

    1999-09-01

    In our previous papers (Sandor et al., 1999a; Sandor et al., 1999b) we have discussed the application of the short time indicators in the planar circular Restricted Three Body Problem (RTBP) and in the Elliptic Restricted Three-Body problem (ERTBP) in order to distinguish between chaotic and regular domains of the phase space in theese problems. The method of stretching numbers was introduced by Voglis and Contopoulos (1994). This method allows a quick distinction between ordered and chaotic regions. We also applied the method of stretching numbers to the elliptic restricted three-body problem. As an extension of our investigation, in the present paper we apply the method of stretching numbers to a realistic Sun-Jupiter-Saturn-Asteroid (SJSA) problem. We represent the structure of the phase-space in the a-e plane, where a is the semimajor axis and e is the eccentricity. For an individual N curve, where N is the average value of stretching numbers. The values of the semimajor axis has been taken from the interval [3.2,5.2] (AU) for a fixed value of the eccentricity of the test particle between e=0 and e=0.4. For a good visualization of the regular and chaotic regions in the a-e plane we have processed the curves of average values calculating the absolut value of their ``derivative'' |frac {Delta N}{Delta a}|, where Delta a = a_{i+1}-ai is the difference between two consecutive initial semimajor axis and Delta N is the corresponding change of the average value of stretching numbers. If this derivative is larger than a certain value (in our case 0.002), the corresponding region between two neighbouring initial conditions is classified as chaotic. The usefulness of this method is based on the very fast and effective way how it approximates the location and size of the regular and chaotic regions. We have found that the structure of the phase-space is very similar in the RTBP and in the ERTB but there is a significant difference in the case of the SJSA. The

  14. To determine block establishment time of supraclavicular brachial plexus block using blunt versus short bevel needle: A prospective randomized trial

    PubMed Central

    Ahuja, V; Thapa, D; Gombar, S; Dhiman, D

    2016-01-01

    Background: Unintentional intraneural injection under ultrasound guidance (USG) with fine caliber needles and lower success rate with large caliber Tuohy needles in supraclavicular brachial plexus block (SCB) have been reported. Materials and Methods: We undertook study to standardize the use of 20-gauge short versus blunt bevel needle for SCB. After approval of Institutional Ethics Committee and written informed consent, patients were randomized using computer-generated random number table to either of the two groups; blunt bevel needle group (n = 30): SCB under USG using 20-gauge Tuohy needle or short bevel needle group (n = 30): SCB under USG using 20-gauge short bevel needle. The primary outcome of the study was time to establishment of sensory and motor block of individual nerves, and secondary outcome was tolerability and any adverse effects. Results: The time to establishment of sensory and motor block in individual nerve territory was similar in both the groups. The complete sensory and motor anesthesia was achieved in 78.3% patients and complete sensory and motor anesthesia after supplementary block was achieved in 86.6% patients. Paresthesias during SCB were recorded in 15 patients. Out of these eight patients were of blunt bevel group and seven patients were of short bevel group. None of the patients experienced any neurological adverse effects. Conclusion: The establishment of sensory and motor blockade of individual nerves was similar to 20-gauge short and blunt bevel needle under ultrasound guide with no neurological adverse events. PMID:27375378

  15. 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...

  16. 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…

  17. Short-Term Memory for Time in Children and Adults: A Behavioral Study and a Model

    ERIC Educational Resources Information Center

    Droit-Volet, Sylvie; Wearden, John; Delgado-Yonger, Maria

    2007-01-01

    This experiment investigated the effect of the short-term retention of duration on temporal discrimination in 5- and 8-year-olds, as well as in adults, by using an episodic temporal generalization task. In each age group, the participants' task was to compare two successive durations (a standard and a comparison duration) separated by a retention…

  18. The Well of Time. Eighteen Short Stories from Philippine Contemporary Literature.

    ERIC Educational Resources Information Center

    Laygo, Teresito M., Comp.

    A collection of eighteen short stories by Filipino writers is presented. The selections represent a variety of images of Filipino culture, both urban and rural, and life styles in northern and southern Philippines. The aim of the anthology is that the student will learn to empathize with experience rendered in language, appreciate the Filipino…

  19. Development of Speech Fluency over a Short Period of Time: Effects of Pedagogic Intervention

    ERIC Educational Resources Information Center

    Tavakoli, Parvaneh; Campbell, Colin; McCormack, Joan

    2016-01-01

    This study investigates the effects of a short-term pedagogic intervention on development of second language (L2) fluency among learners studying English for academic purposes at a UK university. It also examines the interaction between development of fluency and complexity and accuracy. Through a pretest and posttest design, data were collected…

  20. Time-of-day effects on short-term exercise performances in 10- to 11-year-old boys.

    PubMed

    Souissi, Hichem; Chaouachi, Anis; Chamari, Karim; Dogui, Mohamed; Amri, Mohamed; Souissi, Nizar

    2010-11-01

    The purpose of this study was to examine the time-of-day effects on short-term performances in boys. In a balanced and randomized study design, 20 boys performed four anaerobic tests of strength and power (grip strength, Squat-Jump, Five-jump and cycle Wingate tests) at 08:00, 14:00 and 18:00 hr on separate days. The results showed a time-of-day effect on oral temperature. Analysis of variance revealed a significant time-of-day effect for short-term performances for strength, cycle, and jump tests. The post hoc analysis revealed that performances improved significantly from morning to afternoon but no significant differences were noticed between 14:00 and 18:00 hr. The differences between the morning and the afternoon (the highest value measured either at 14:00 or at 18:00 hr) reached 5.9% for grip strength, 3.5% for the squat jump test, 5% for the five jump test, and 5.5% for P(peak) and 6% for P(mean) during the Wingate test. A significant positive correlation was found between temperature and short-term performances. In conclusion, a time-of-day effect in the child's maximal short-term exercise performances exists in relation with core temperature. Such variations would have pronounced effects when expressed in training programs and competitions.

  1. Effects of the Coordination Exercise Program on School Children's Agility: Short-Time Program during School Recess

    ERIC Educational Resources Information Center

    Yasumitsu, Tatsuo; Nogawa, Haruo; Hatano, Yoshiro

    2011-01-01

    This study examined the impact of a short-time coordination program conducted during recess periods on improving agility in elementary school students. The subjects consisted of 60 third grade students, who were randomly assigned to an experimental group (n = 29) and a control group (n = 31). The experimental group completed a coordination program…

  2. Sulfur revisited.

    PubMed

    Lin, A N; Reimer, R J; Carter, D M

    1988-03-01

    Sulfur is a time-honored therapeutic agent useful in a variety of dermatologic disorders. Its keratolytic action is due to formation of hydrogen sulfide through a reaction that depends upon direct interaction between sulfur particles and keratinocytes. The smaller the particle size, the greater the degree of such interaction and the greater the therapeutic efficacy. When applied topically, sulfur induces various histologic changes, including hyperkeratosis, acanthosis, and dilatation of dermal vasculature. One study showed that sulfur was comedogenic when applied onto human and rabbit skin, findings that were not reproduced in other studies. About 1% of topically applied sulfur is systemically absorbed. Adverse effects from topically applied sulfur are uncommon and are mainly limited to the skin. In infants, however, fatal outcome after extensive application has been reported.

  3. Cats protecting birds revisited.

    PubMed

    Fan, Meng; Kuang, Yang; Feng, Zhilan

    2005-09-01

    In this paper, we revisit the dynamical interaction among prey (bird), mesopredator (rat), and superpredator (cat) discussed in [Courchamp, F., Langlais, M., Sugihara, G., 1999. Cats protecting birds: modelling the mesopredator release effect. Journal of Animal Ecology 68, 282-292]. First, we develop a prey-mesopredator-superpredator (i.e., bird-rat-cat, briefly, BRC) model, where the predator's functional responses are derived based on the classical Holling's time budget arguments. Our BRC model overcomes several model construction problems in Courchamp et al. (1999), and admits richer, reasonable and realistic dynamics. We explore the possible control strategies to save or restore the bird by controlling or eliminating the rat or the cat when the bird is endangered. We establish the existence of two types of mesopredator release phenomena: severe mesopredator release, where once superpredators are suppressed, a burst of mesopredators follows which leads their shared prey to extinction; and mild mesopredator release, where the mesopredator release could assert more negative impact on the endemic prey but does not lead the endemic prey to extinction. A sharp sufficient criterion is established for the occurrence of severe mesopredator release. We also show that, in a prey-mesopredator-superpredator trophic food web, eradication of introduced superpredators such as feral domestic cats in the BRC model, is not always the best solution to protect endemic insular prey. The presence of a superpredator may have a beneficial effect in such systems.

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

    SciTech Connect

    Fine, Dana S.; Sawin, Stephen

    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.

  5. 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 (ΔS), 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 ± ΔS = 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

  6. Iodine revisited.

    PubMed

    Cooper, Rose A

    2007-06-01

    Iodine is an antiseptic that has been used in wound care for more than 150 years. Traditional formulations of iodine had serious limitations that were reduced in later products. Much has been written about iodine and opinions on its clinical efficacy are divided. There have been reviews of the chemical properties of iodine, its antimicrobial activity, human physiology, cytotoxicity and its clinical effectiveness, but few have addressed all these aspects. With the recent development of iodine-containing wound care products and the continued publication of laboratory and clinical studies, it seems timely to reassess the evidence relating to the effectiveness of iodine for treating wounds. This literature review attempts to provide an appropriate chemical and physiological background of the characteristics of iodine in order to provide a sound basis for understanding the available microbiological and clinical data. It will show that understanding the factors that contribute to the activity and potential cytotoxicity of iodine are important in evaluating the clinical evidence. Although definitive studies are needed, the sustained delivery of low doses of free iodine offers the potential to inhibit a broad range of microbial species without selecting for resistant strains or inducing cytotoxic effects.

  7. Palatogram revisited

    PubMed Central

    Jain, Ashish R.; Venkat Prasad, M. K.; Ariga, Padma

    2014-01-01

    It is the responsibility of the dentist to fabricate a denture that is fully functional and perfectly esthetic. One prime oral function that has always been overlooked in this regard is speech. It has been thought that speech will follow mere replacement of teeth and that it is the patient's duty to fine tune this function with practice. Phonetics, esthetics, function and comfort form the foundation of a successful prosthodontic treatment. Accurate approximation of palatal contours of a maxillary complete denture to a patient's tongue can improve speech intelligibility, if other factors such as tooth position, occlusal plane and occlusal vertical dimension are satisfactory. Customizing palatal contours of a maxillary complete denture can be accomplished by using tissue-conditioning material, which provides sufficient working time for a patient to pronounce a series of sibilant sounds while recording dynamic impression of the tongue. This article describes a technique of obtaining palatogram and customizing palatal contours of a maxillary complete denture with autopolymerizing acrylic resin to improve the intelligibility of speech. PMID:24808716

  8. Short-time focused ultrasound hyperthermia enhances liposomal doxorubicin delivery and antitumor efficacy for brain metastasis of breast cancer.

    PubMed

    Wu, Sheng-Kai; Chiang, Chi-Feng; Hsu, Yu-Hone; Lin, Tzu-Hung; Liou, Houng-Chi; Fu, Wen-Mei; Lin, Win-Li

    2014-01-01

    The blood-brain/tumor barrier inhibits the uptake and accumulation of chemotherapeutic drugs. Hyperthermia can enhance the delivery of chemotherapeutic agent into tumors. In this study, we investigated the effects of short-time focused ultrasound (FUS) hyperthermia on the delivery and therapeutic efficacy of pegylated liposomal doxorubicin (PLD) for brain metastasis of breast cancer. Murine breast cancer 4T1-luc2 cells expressing firefly luciferase were injected into female BALB/c mice striatum tissues and used as a brain metastasis model. The mice were intravenously injected with PLD (5 mg/kg) with/without 10-minute transcranial FUS hyperthermia on day 6 after tumor implantation. The amounts of doxorubicin accumulated in the normal brain tissues and tumor tissues with/without FUS hyperthermia were measured using fluorometry. The tumor growth for the control, hyperthermia, PLD, and PLD + hyperthermia groups was measured using an IVIS spectrum system every other day from day 3 to day 11. Cell apoptosis and tumor characteristics were assessed using immunohistochemistry. Short-time FUS hyperthermia was able to significantly enhance the PLD delivery into brain tumors. The tumor growth was effectively inhibited by a single treatment of PLD + hyperthermia compared with both PLD alone and short-time FUS hyperthermia alone. Immunohistochemical examination further demonstrated the therapeutic efficacy of PLD plus short-time FUS hyperthermia for brain metastasis of breast cancer. The application of short-time FUS hyperthermia after nanodrug injection may be an effective approach to enhance nanodrug delivery and improve the treatment of metastatic cancers.

  9. 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

    ... 25 Indians 1 2013-04-01 2013-04-01 false Does the Job Training Program provide part-time training or short-term training? 26.30 Section 26.30 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR HUMAN SERVICES JOB PLACEMENT AND TRAINING PROGRAM Training Services § 26.30 Does the Job Training Program provide part-time training...

  10. 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

    ... 25 Indians 1 2014-04-01 2014-04-01 false Does the Job Training Program provide part-time training or short-term training? 26.30 Section 26.30 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR HUMAN SERVICES JOB PLACEMENT AND TRAINING PROGRAM Training Services § 26.30 Does the Job Training Program provide part-time training...

  11. Target Recognition Using Late-Time Returns from Ultra-Wideband, Short-Pulse Radar

    DTIC Science & Technology

    2004-06-01

    neglecting terms associated with surface resistance. The recognition sensor illuminates the target with a series of ultra-wideband, short radar pulses...the incident radar wave . Picture yourself looking into a mirror. If you can see your own face, you see the broadside of the mirror. Broadside is used...as an azimuth reference. Broadside illumination occurs when the incident wave approaches the object’s surface in a direction parallel to the surface

  12. Short-term pollution forecasts based on linear and nonlinear methods of time series analysis

    NASA Astrophysics Data System (ADS)

    Russo, A.; Trigo, R. M.

    2012-04-01

    Urban air pollution is a complex mixture of toxic components, which may induce acute and chronic responses from sensitive groups, such as children and people with previous heart and respiratory insufficiencies. However, air pollution, presents a highly chaotic and non-linear behavior. In this work we analyzed several pollutants time series recorded in the urban area of Lisbon (Portugal) for the 2002-2006 period. Linear and nonlinear methods were applied in order to assess NO2, PM10 and O3 main trends and fluctuations and finally, to produce daily forecasts of the referred pollutants. Here we evaluate the potential of linear and non-linear neural networks (NN) to produce short-term forecasts, and also the contribution of meteorological variables (daily mean temperature, radiation, wind speed and direction, boundary layer height, humidity) to pollutants dispersion. Additionally, we assess the role of large-scale circulation patterns, usually referred as Weather types (WT) (from the ERA40/ECMWF and ECMWF SLP database) towards the occurrence of critical pollution events identified previously. The presence and importance of trends and fluctuation is addressed by means of two modelling approaches: (1) raw data modelling; (2) residuals modelling (after the removal of the trends from the original data). The relative importance of two periodic components, the weekly and the monthly cycles, is addressed. For the three pollutants, the approach based on the removal of the weekly cycle presents the best results, comparatively to the removal of the monthly cycle or to the use of the raw data. The best predictors are chosen independently for each monitoring station and pollutant through an objective procedure (backward stepwise regression). The analysis reveals that the most significant variables in predicting NO2 concentration are several NO2 measures, wind direction and speed and global radiation, while for O3 correspond to several O3 measures, O3 precursors and WT

  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

  14. 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.

  15. Time-resolved neuroimaging of visual short term memory consolidation by post-perceptual attention shifts.

    PubMed

    Hecht, Marcus; Thiemann, Ulf; Freitag, Christine M; Bender, Stephan

    2016-01-15

    Post-perceptual cues can enhance visual short term memory encoding even after the offset of the visual stimulus. However, both the mechanisms by which the sensory stimulus characteristics are buffered as well as the mechanisms by which post-perceptual selective attention enhances short term memory encoding remain unclear. We analyzed late post-perceptual event-related potentials (ERPs) in visual change detection tasks (100ms stimulus duration) by high-resolution ERP analysis to elucidate these mechanisms. The effects of early and late auditory post-cues (300ms or 850ms after visual stimulus onset) as well as the effects of a visual interference stimulus were examined in 27 healthy right-handed adults. Focusing attention with post-perceptual cues at both latencies significantly improved memory performance, i.e. sensory stimulus characteristics were available for up to 850ms after stimulus presentation. Passive watching of the visual stimuli without auditory cue presentation evoked a slow negative wave (N700) over occipito-temporal visual areas. N700 was strongly reduced by a visual interference stimulus which impeded memory maintenance. In contrast, contralateral delay activity (CDA) still developed in this condition after the application of auditory post-cues and was thereby dissociated from N700. CDA and N700 seem to represent two different processes involved in short term memory encoding. While N700 could reflect visual post processing by automatic attention attraction, CDA may reflect the top-down process of searching selectively for the required information through post-perceptual attention.

  16. Application of a short-time version of the Equalization-Cancellation model to speech intelligibility experiments with speech maskers.

    PubMed

    Wan, Rui; Durlach, Nathaniel I; Colburn, H Steven

    2014-08-01

    A short-time-processing version of the Equalization-Cancellation (EC) model of binaural processing is described and applied to speech intelligibility tasks in the presence of multiple maskers, including multiple speech maskers. This short-time EC model, called the STEC model, extends the model described by Wan et al. [J. Acoust. Soc. Am. 128, 3678-3690 (2010)] to allow the EC model's equalization parameters τ and α to be adjusted as a function of time, resulting in improved masker cancellation when the dominant masker location varies in time. Using the Speech Intelligibility Index, the STEC model is applied to speech intelligibility with maskers that vary in number, type, and spatial arrangements. Most notably, when maskers are located on opposite sides of the target, this STEC model predicts improved thresholds when the maskers are modulated independently with speech-envelope modulators; this includes the most relevant case of independent speech maskers. The STEC model describes the spatial dependence of the speech reception threshold with speech maskers better than the steady-state model. Predictions are also improved for independently speech-modulated noise maskers but are poorer for reversed-speech maskers. In general, short-term processing is useful, but much remains to be done in the complex task of understanding speech in speech maskers.

  17. Existence of short-time approximations of any polynomial order for the computation of density matrices by path integral methods

    NASA Astrophysics Data System (ADS)

    Predescu, Cristian

    2004-05-01

    In this paper I provide significant mathematical evidence in support of the existence of direct short-time approximations of any polynomial order for the computation of density matrices of physical systems described by arbitrarily smooth and bounded from below potentials. While for Theorem 2, which is “experimental,” I only provide a “physicist’s” proof, I believe the present development is mathematically sound. As a verification, I explicitly construct two short-time approximations to the density matrix having convergence orders 3 and 4, respectively. Furthermore, in Appendix B, I derive the convergence constant for the trapezoidal Trotter path integral technique. The convergence orders and constants are then verified by numerical simulations. While the two short-time approximations constructed are of sure interest to physicists and chemists involved in Monte Carlo path integral simulations, the present paper is also aimed at the mathematical community, who might find the results interesting and worth exploring. I conclude the paper by discussing the implications of the present findings with respect to the solvability of the dynamical sign problem appearing in real-time Feynman path integral simulations.

  18. Human brain detects short-time nonlinear predictability in the temporal fine structure of deterministic chaotic sounds

    NASA Astrophysics Data System (ADS)

    Itoh, Kosuke; Nakada, Tsutomu

    2013-04-01

    Deterministic nonlinear dynamical processes are ubiquitous in nature. Chaotic sounds generated by such processes may appear irregular and random in waveform, but these sounds are mathematically distinguished from random stochastic sounds in that they contain deterministic short-time predictability in their temporal fine structures. We show that the human brain distinguishes deterministic chaotic sounds from spectrally matched stochastic sounds in neural processing and perception. Deterministic chaotic sounds, even without being attended to, elicited greater cerebral cortical responses than the surrogate control sounds after about 150 ms in latency after sound onset. Listeners also clearly discriminated these sounds in perception. The results support the hypothesis that the human auditory system is sensitive to the subtle short-time predictability embedded in the temporal fine structure of sounds.

  19. Kidney stone imaging with 3D ultra-short echo time (UTE) magnetic resonance imaging. A phantom study.

    PubMed

    Ibrahim, El-Sayed H; Pooley, Robert A; Bridges, Mellena D; Cernigliaro, Joseph G; Haley, William E

    2014-01-01

    Computed tomography (CT) is the current gold standard for imaging kidney stones, albeit at the cost of radiation exposure. Conventional magnetic resonance imaging (MRI) sequences are insensitive to detecting the stones because of their appearance as a signal void. With the development of 2D ultra-short echo-time (UTE) MRI sequences, it becomes possible to image kidney stones in vitro. In this work, we optimize and implement a modified 3D UTE MRI sequence for imaging kidney stones embedded in agarose phantoms mimicking the kidney tissue and in urine phantoms at 3.0T. The proposed technique is capable of imaging the stones with high spatial resolution in a short scan time.

  20. Ensemble forecasting of short-term system scale irrigation demands using real-time flow data and numerical weather predictions

    NASA Astrophysics Data System (ADS)

    Perera, Kushan C.; Western, Andrew W.; Robertson, David E.; George, Biju; Nawarathna, Bandara

    2016-06-01

    Irrigation demands fluctuate in response to weather variations and a range of irrigation management decisions, which creates challenges for water supply system operators. This paper develops a method for real-time ensemble forecasting of irrigation demand and applies it to irrigation command areas of various sizes for lead times of 1 to 5 days. The ensemble forecasts are based on a deterministic time series model coupled with ensemble representations of the various inputs to that model. Forecast inputs include past flow, precipitation, and potential evapotranspiration. These inputs are variously derived from flow observations from a modernized irrigation delivery system; short-term weather forecasts derived from numerical weather prediction models and observed weather data available from automatic weather stations. The predictive performance for the ensemble spread of irrigation demand was quantified using rank histograms, the mean continuous rank probability score (CRPS), the mean CRPS reliability and the temporal mean of the ensemble root mean squared error (MRMSE). The mean forecast was evaluated using root mean squared error (RMSE), Nash-Sutcliffe model efficiency (NSE) and bias. The NSE values for evaluation periods ranged between 0.96 (1 day lead time, whole study area) and 0.42 (5 days lead time, smallest command area). Rank histograms and comparison of MRMSE, mean CRPS, mean CRPS reliability and RMSE indicated that the ensemble spread is generally a reliable representation of the forecast uncertainty for short lead times but underestimates the uncertainty for long lead times.

  1. Time-resolved measurement of the quantum states of photons using two-photon interference with short-time reference pulses

    SciTech Connect

    Ren Changliang; Hofmann, Holger F.

    2011-09-15

    To fully utilize the energy-time degree of freedom of photons for optical quantum-information processes, it is necessary to control and characterize the temporal quantum states of the photons at extremely short time scales. For measurements of the temporal coherence of the quantum states beyond the time resolution of available detectors, two-photon interference with a photon in a short-time reference pulse may be a viable alternative. In this paper, we derive the temporal measurement operators for the bunching statistics of a single-photon input state with a photon from a weak coherent reference pulse. It is shown that the effects of the pulse shape of the reference pulse can be expressed in terms of a spectral filter selecting the bandwidth within which the measurement can be treated as an ideal projection on eigenstates of time. For full quantum tomography, temporal coherence can be determined by using superpositions of reference pulses at two different times. Moreover, energy-time entanglement can be evaluated based on the two-by-two entanglement observed in the coherences between pairs of detection times.

  2. Long- and short-time analysis of heartbeat sequences: Correlation with mortality risk in congestive heart failure patients

    NASA Astrophysics Data System (ADS)

    Allegrini, P.; Balocchi, R.; Chillemi, S.; Grigolini, P.; Hamilton, P.; Maestri, R.; Palatella, L.; Raffaelli, G.

    2003-06-01

    We analyze RR heartbeat sequences with a dynamic model that satisfactorily reproduces both the long- and the short-time statistical properties of heart beating. These properties are expressed quantitatively by means of two significant parameters, the scaling δ concerning the asymptotic effects of long-range correlation, and the quantity 1-π establishing the amount of uncorrelated fluctuations. We find a correlation between the position in the phase space (δ,π) of patients with congestive heart failure and their mortality risk.

  3. Long- and short-time analysis of heartbeat sequences: correlation with mortality risk in congestive heart failure patients.

    PubMed

    Allegrini, P; Balocchi, R; Chillemi, S; Grigolini, P; Hamilton, P; Maestri, R; Palatella, L; Raffaelli, G

    2003-06-01

    We analyze RR heartbeat sequences with a dynamic model that satisfactorily reproduces both the long- and the short-time statistical properties of heart beating. These properties are expressed quantitatively by means of two significant parameters, the scaling delta concerning the asymptotic effects of long-range correlation, and the quantity 1-pi establishing the amount of uncorrelated fluctuations. We find a correlation between the position in the phase space (delta, pi) of patients with congestive heart failure and their mortality risk.

  4. Impact of Short-Time Urine Freezing on the Sensitivity of an Established Schistosoma Real-Time PCR Assay

    PubMed Central

    Kenguele, Hilaire M.; Adegnika, Ayola A.; Nkoma, Anne-Marie; Ateba-Ngoa, Ulysse; Mbong, Mirabeau; Zinsou, Jeannot; Lell, Bertrand; Verweij, Jaco J.

    2014-01-01

    Urogenital schistosomiaisis is a serious public health problem in sub-Saharan Africa. In this study, we have updated an established real-time polymerase chain reaction (PCR) routinely used in our laboratory. Schistosoma genus-specific real-time PCR was performed on DNA isolated from 85 urine samples and pellets obtained after centrifugation without and after frozen storage. The results revealed that concentration by centrifugation of the urine samples and freezing of the samples before extracting DNA improves the sensitivity of the PCR. PMID:24710612

  5. Effect of short-time hydrothermal pretreatment of kitchen waste on biohydrogen production: fluorescence spectroscopy coupled with parallel factor analysis.

    PubMed

    Li, Mingxiao; Xia, Tianming; Zhu, Chaowei; Xi, Beidou; Jia, Xuan; Wei, Zimin; Zhu, Jinlong

    2014-11-01

    The enhancement of bio-hydrogen production from kitchen waste by a short-time hydrothermal pretreatment at different temperatures (i.e., 90°C, 120°C, 150°C and 200°C) was evaluated. The effects of temperature for the short-time hydrothermal pretreatment on kitchen waste protein conversion and dissolved organic matter characteristics were investigated in this study. A maximum bio-hydrogen yield of 81.27mL/g VS was acquired at 200°C by the short-time hydrothermal pretreatment during the anaerobic fermentative hydrogen production. Analysis of the dissolved organic matter composition showed that the protein-like peak dominated and that three fluorescent components were separated using fluorescence excitation-emission matrix spectra coupled with the parallel factor model. The maximum fluorescence intensities of protein-like components decomposed through the parallel factor analysis has a significant correlation with the raw protein concentration, showed by further correlation analysis. This directly impacted the hydrogen production ability.

  6. 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…

  7. A Hydrostatic Paradox Revisited

    ERIC Educational Resources Information Center

    Ganci, Salvatore

    2012-01-01

    This paper revisits a well-known hydrostatic paradox, observed when turning upside down a glass partially filled with water and covered with a sheet of light material. The phenomenon is studied in its most general form by including the mass of the cover. A historical survey of this experiment shows that a common misunderstanding of the phenomenon…

  8. Parametric Resonance Revisited

    NASA Astrophysics Data System (ADS)

    van den Broeck, C.; Bena, I.

    The phenomenon of parametric resonance is revisited. Several physical examples are reviewed and an exactly solvable model is discussed. A mean field theory is presented for globally coupled parametric oscillators with randomly distributed phases. A new type of collective instability appears, which is similar in nature to that of noise induced phase transitions.

  9. Concept Image Revisited

    ERIC Educational Resources Information Center

    Bingolbali, Erhan; Monaghan, John

    2008-01-01

    Concept image and concept definition is an important construct in mathematics education. Its use, however, has been limited to cognitive studies. This article revisits concept image in the context of research on undergraduate students' understanding of the derivative which regards the context of learning as paramount. The literature, mainly on…

  10. Revisiting Bioaccumulation Criteria

    EPA Science Inventory

    The objective of workgroup 5 was to revisit the B(ioaccumulation) criteria that are currently being used to identify POPs under the Stockholm Convention and PBTs under CEPA, TSCA, REACh and other programs. Despite the lack of a recognized definition for a B substance, we defined ...

  11. The Linguistic Repertoire Revisited

    ERIC Educational Resources Information Center

    Busch, Brigitta

    2012-01-01

    This article argues for the relevance of poststructuralist approaches to the notion of a linguistic repertoire and introduces the notion of language portraits as a basis for empirical study of the way in which speakers conceive and represent their heteroglossic repertoires. The first part of the article revisits Gumperz's notion of a linguistic…

  12. Colloquial Hebrew Imperatives Revisited

    ERIC Educational Resources Information Center

    Bolozky, Shmuel

    2009-01-01

    In revisiting Bolozky's [Bolozky, Shmuel, 1979. "On the new imperative in colloquial Hebrew." "Hebrew Annual Review" 3, 17-24] and Bat-El's [Bat-El, Outi, 2002. "True truncation in colloquial Hebrew imperatives." "Language" 78(4), 651-683] analyses of colloquial Hebrew imperatives, the article argues for restricting Imperative Truncation to the…

  13. 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...

  14. Thermalization time of thin metal film heated by short pulse laser

    NASA Astrophysics Data System (ADS)

    Xu, Hong-Yu; Zhang, Yuan-Chong; Song, Ya-Qin; Chen, Dian-Yun

    2004-10-01

    Based on the hyperbolic two-step heat conduction model, using the Laplace transform and numerical inverse transform method (Riemann-sum approximation method), the thermal behaviour of thin metal films has been studied during femtosecond pulse laser heating. Also the thermalization time, which is the time for the electron gas and solid lattice to reach thermal balance, has been studied in detail. The values of thermalization time for silver (Ag), gold (Au), copper (Cu) and lead (Pb) are obtained. The effects of material parameters of the thin metal film on the thermalization time are considered for the four kinds of metals by changing one of the parameters and regarding the other parameters as constant. For a typical metal material, the order of the thermalization time is of the order of hundreds of picoseconds. The thermalization time decays exponentially with the increase of phonon-electron coupling factor or electron gas thermal conductivity and it increases linearly with the increase of the ratio of lattice heat capacity to electron gas heat capacity. However, the relaxation time of the electron gas has very little effect on the thermalization time.

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

    SciTech Connect

    Carbajo, J.J. )

    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.

  16. Time Resolved Studies of ZnO(Eu) Nanostructure Luminescence Using Short Synchrotron Radiation Pulses

    SciTech Connect

    Heigl, F.; Jurgensen, A.; Zhou, X.-T.; Murphy, M.; Ko, J.Y.P.; Lam, S.; Sham, T.K.; Regier, T.; Blyth, R.I.R.; Coulthard, I.; Zuin, L.; Hu, Y.-F.; Armelao, L.; Gordon, R.A.; Brewe, D.

    2008-10-06

    X-ray excited optical luminescence (XEOL) is a well established technique to study nano structured light emitting materials. XEOL bares the essential features necessary for the study of advanced nano structured materials like element specifity, good quantum efficiency, and easy approach for time resolution. Being sensitive to the geometry of the material on a nano-scale, luminescence gives insight into the phenomenologic correlation of structural, optical, and electronic properties. Besides structural aspects we study the time behavior of nanostructured ZnO (Eu) in a pump-probe like experiment, using the time structure of synchrotron radiation.

  17. Short-term sandbar variability based on video imagery: Comparison between Time-Average and Time-Variance techniques

    USGS Publications Warehouse

    Guedes, R.M.C.; Calliari, L.J.; Holland, K.T.; Plant, N.G.; Pereira, P.S.; Alves, F.N.A.

    2011-01-01

    Time-exposure intensity (averaged) images are commonly used to locate the nearshore sandbar position (xb), based on the cross-shore locations of maximum pixel intensity (xi) of the bright bands in the images. It is not known, however, how the breaking patterns seen in Variance images (i.e. those created through standard deviation of pixel intensity over time) are related to the sandbar locations. We investigated the suitability of both Time-exposure and Variance images for sandbar detection within a multiple bar system on the southern coast of Brazil, and verified the relation between wave breaking patterns, observed as bands of high intensity in these images and cross-shore profiles of modeled wave energy dissipation (xD). Not only is Time-exposure maximum pixel intensity location (xi-Ti) well related to xb, but also to the maximum pixel intensity location of Variance images (xi-Va), although the latter was typically located 15m offshore of the former. In addition, xi-Va was observed to be better associated with xD even though xi-Ti is commonly assumed as maximum wave energy dissipation. Significant wave height (Hs) and water level (??) were observed to affect the two types of images in a similar way, with an increase in both Hs and ?? resulting in xi shifting offshore. This ??-induced xi variability has an opposite behavior to what is described in the literature, and is likely an indirect effect of higher waves breaking farther offshore during periods of storm surges. Multiple regression models performed on xi, Hs and ?? allowed the reduction of the residual errors between xb and xi, yielding accurate estimates with most residuals less than 10m. Additionally, it was found that the sandbar position was best estimated using xi-Ti (xi-Va) when xb was located shoreward (seaward) of its mean position, for both the first and the second bar. Although it is unknown whether this is an indirect hydrodynamic effect or is indeed related to the morphology, we found that this

  18. Parvalbumin tunes spike-timing and efferent short-term plasticity in striatal fast spiking interneurons.

    PubMed

    Orduz, David; Bischop, Don Patrick; Schwaller, Beat; Schiffmann, Serge N; Gall, David

    2013-07-01

      Striatal fast spiking interneurons (FSIs) modulate output of the striatum by synchronizing medium-sized spiny neurons (MSNs). Recent studies have broadened our understanding of FSIs, showing that they are implicated in severe motor disorders such as parkinsonism, dystonia and Tourette syndrome. FSIs are the only striatal neurons to express the calcium-binding protein parvalbumin (PV). This selective expression of PV raises questions about the functional role of this Ca(2+) buffer in controlling FSI Ca(2+) dynamics and, consequently, FSI spiking mode and neurotransmission. To study the functional involvement of FSIs in striatal microcircuit activity and the role of PV in FSI function, we performed perforated patch recordings on enhanced green fluorescent protein-expressing FSIs in brain slices from control and PV-/- mice. Our results revealed that PV-/- FSIs fired more regularly and were more excitable than control FSIs by a mechanism in which Ca(2+) buffering is linked to spiking activity as a result of the activation of small conductance Ca(2+)-dependent K(+) channels. A modelling approach of striatal FSIs supports our experimental results. Furthermore, PV deletion modified frequency-specific short-term plasticity at inhibitory FSI to MSN synapses. Our results therefore reinforce the hypothesis that in FSIs, PV is crucial for fine-tuning of the temporal responses of the FSI network and for the orchestration of MSN populations. This, in turn, may play a direct role in the generation and pathology-related worsening of motor rhythms.

  19. Short time sports exercise boosts motor imagery patterns: implications of mental practice in rehabilitation programs

    PubMed Central

    Wriessnegger, Selina C.; Steyrl, David; Koschutnig, Karl; Müller-Putz, Gernot R.

    2014-01-01

    Motor imagery (MI) is a commonly used paradigm for the study of motor learning or cognitive aspects of action control. The rationale for using MI training to promote the relearning of motor function arises from research on the functional correlates that MI shares with the execution of physical movements. While most of the previous studies investigating MI were based on simple movements in the present study a more attractive mental practice was used to investigate cortical activation during MI. We measured cerebral responses with functional magnetic resonance imaging (fMRI) in twenty three healthy volunteers as they imagined playing soccer or tennis before and after a short physical sports exercise. Our results demonstrated that only 10 min of training are enough to boost MI patterns in motor related brain regions including premotor cortex and supplementary motor area (SMA) but also fronto-parietal and subcortical structures. This supports previous findings that MI has beneficial effects especially in combination with motor execution when used in motor rehabilitation or motor learning processes. We conclude that sports MI combined with an interactive game environment could be a promising additional tool in future rehabilitation programs aiming to improve upper or lower limb functions or support neuroplasticity. PMID:25071505

  20. Parvalbumin tunes spike-timing and efferent short-term plasticity in striatal fast spiking interneurons

    PubMed Central

    Orduz, David; Bischop, Don Patrick; Schwaller, Beat; Schiffmann, Serge N; Gall, David

    2013-01-01

    Striatal fast spiking interneurons (FSIs) modulate output of the striatum by synchronizing medium-sized spiny neurons (MSNs). Recent studies have broadened our understanding of FSIs, showing that they are implicated in severe motor disorders such as parkinsonism, dystonia and Tourette syndrome. FSIs are the only striatal neurons to express the calcium-binding protein parvalbumin (PV). This selective expression of PV raises questions about the functional role of this Ca2+ buffer in controlling FSI Ca2+ dynamics and, consequently, FSI spiking mode and neurotransmission. To study the functional involvement of FSIs in striatal microcircuit activity and the role of PV in FSI function, we performed perforated patch recordings on enhanced green fluorescent protein-expressing FSIs in brain slices from control and PV−/− mice. Our results revealed that PV−/− FSIs fired more regularly and were more excitable than control FSIs by a mechanism in which Ca2+ buffering is linked to spiking activity as a result of the activation of small conductance Ca2+-dependent K+ channels. A modelling approach of striatal FSIs supports our experimental results. Furthermore, PV deletion modified frequency-specific short-term plasticity at inhibitory FSI to MSN synapses. Our results therefore reinforce the hypothesis that in FSIs, PV is crucial for fine-tuning of the temporal responses of the FSI network and for the orchestration of MSN populations. This, in turn, may play a direct role in the generation and pathology-related worsening of motor rhythms. PMID:23551945

  1. Accurate estimation of entropy in very short physiological time series: the problem of atrial fibrillation detection in implanted ventricular devices.

    PubMed

    Lake, Douglas E; Moorman, J Randall

    2011-01-01

    Entropy estimation is useful but difficult in short time series. For example, automated detection of atrial fibrillation (AF) in very short heart beat interval time series would be useful in patients with cardiac implantable electronic devices that record only from the ventricle. Such devices require efficient algorithms, and the clinical situation demands accuracy. Toward these ends, we optimized the sample entropy measure, which reports the probability that short templates will match with others within the series. We developed general methods for the rational selection of the template length m and the tolerance matching r. The major innovation was to allow r to vary so that sufficient matches are found for confident entropy estimation, with conversion of the final probability to a density by dividing by the matching region volume, 2r(m). The optimized sample entropy estimate and the mean heart beat interval each contributed to accurate detection of AF in as few as 12 heartbeats. The final algorithm, called the coefficient of sample entropy (COSEn), was developed using the canonical MIT-BIH database and validated in a new and much larger set of consecutive Holter monitor recordings from the University of Virginia. In patients over the age of 40 yr old, COSEn has high degrees of accuracy in distinguishing AF from normal sinus rhythm in 12-beat calculations performed hourly. The most common errors are atrial or ventricular ectopy, which increase entropy despite sinus rhythm, and atrial flutter, which can have low or high entropy states depending on dynamics of atrioventricular conduction.

  2. Use of extremely short Förster 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

  3. Time-dependent intensity and phase measurements of ultrashort laser pulses as short as 10 fs

    SciTech Connect

    DeLong, K.W.; Fittinghoff, D.N.; Ladera, C.L.; Trebino, R.; Taft, G.; Rundquist, A.; Murnane, M.M.; Kapteyn, H.C.; Christov, I.P.

    1995-05-01

    Frequency-Resolved Optical Gating (FROG) measures the time-dependent intensity and phase of an ultrashort laser pulse. Using FROG, we have tested theories for the operation of sub{minus}10 fs laser oscillators.

  4. The Effective Mutation Rate at Y Chromosome Short Tandem Repeats, with Application to Human Population-Divergence Time

    PubMed Central

    Zhivotovsky, Lev A.; Underhill, Peter A.; Cinnioğlu, Cengiz; Kayser, Manfred; Morar, Bharti; Kivisild, Toomas; Scozzari, Rosaria; Cruciani, Fulvio; Destro-Bisol, Giovanni; Spedini, Gabriella; Chambers, Geoffrey K.; Herrera, Rene J.; Yong, Kiau Kiun; Gresham, David; Tournev, Ivailo; Feldman, Marcus W.; Kalaydjieva, Luba

    2004-01-01

    We estimate an effective mutation rate at an average Y chromosome short-tandem repeat locus as 6.9×10-4 per 25 years, with a standard deviation across loci of 5.7×10-4, using data on microsatellite variation within Y chromosome haplogroups defined by unique-event polymorphisms in populations with documented short-term histories, as well as comparative data on worldwide populations at both the Y chromosome and various autosomal loci. This value is used to estimate the times of the African Bantu expansion, the divergence of Polynesian populations (the Maoris, Cook Islanders, and Samoans), and the origin of Gypsy populations from Bulgaria. PMID:14691732

  5. Femtosecond timing-jitter between photo-cathode laser and ultra-short electron bunches by means of hybrid compression

    NASA Astrophysics Data System (ADS)

    Pompili, R.; Anania, M. P.; Bellaveglia, M.; Biagioni, A.; Castorina, G.; Chiadroni, E.; Cianchi, A.; Croia, M.; Di Giovenale, D.; Ferrario, M.; Filippi, F.; Gallo, A.; Gatti, G.; Giorgianni, F.; Giribono, A.; Li, W.; Lupi, S.; Mostacci, A.; Petrarca, M.; Piersanti, L.; Di Pirro, G.; Romeo, S.; Scifo, J.; Shpakov, V.; Vaccarezza, C.; Villa, F.

    2016-08-01

    The generation of ultra-short electron bunches with ultra-low timing-jitter relative to the photo-cathode (PC) laser has been experimentally proved for the first time at the SPARC_LAB test-facility (INFN-LNF, Frascati) exploiting a two-stage hybrid compression scheme. The first stage employs RF-based compression (velocity-bunching), which shortens the bunch and imprints an energy chirp on it. The second stage is performed in a non-isochronous dogleg line, where the compression is completed resulting in a final bunch duration below 90 fs (rms). At the same time, the beam arrival timing-jitter with respect to the PC laser has been measured to be lower than 20 fs (rms). The reported results have been validated with numerical simulations.

  6. Dominant formation of the microsized carbon coils by a short time SF6 flow incorporation during the initial deposition stage.

    PubMed

    Jeon, Young-Chul; Yi, Soung Soo; Kim, Sung-Hoon

    2013-08-01

    By SF6 gas incorporation for relatively short time during the initial deposition stage, carbon coils could be formed on nickel catalyst layer-deposited silicon oxide substrate using C2H2 and H2 as source gases under thermal chemical vapor deposition system. The characteristics (formation density and morphology) of as-grown carbon coils were investigated as a function of SF6 flow injection time. 5-min SF6 flow injection time is appropriate to produce the dominant microsized geometry for carbon coils without the appearance of the nanosized carbon coils. The geometry for the microsized carbon coils follows a typical double-helix structure and the shape of the rings constituting the coils is a flat-type. Fluorine's intrinsic etching characteristics for the nanosized carbon coils during the initial deposition stage seems to be the cause for the dominant formation of the microsized carbon coils in the case of 5-min SF6 flow injection time.

  7. Potential denitrification and N2O efflux from riparian soils during short-time flooding

    NASA Astrophysics Data System (ADS)

    Shrestha, Juna; Niklaus, Pascal; Frossard, Emmanuel; Tockner, Klement; Luster, Jörg

    2010-05-01

    Denitrification can contribute significantly to the filter function of soils because it leads to permanent removal of nitrate. Denitrification has been intensively studied in wetlands characterized by seasonal wet-dry cycles and in riparian buffer zones between agricultural land and rivers. Less attention has been paid to the effects of overbank flooding in river floodplains, in particular to short terms effect of flood pulses. We monitored denitrification potential, N2O efflux and related parameters in soils of a restored reach of the Alpine river Thur in northeastern Switzerland during and after flashy flood events. The study was part of the interdisciplinary project cluster RECORD, which was initiated to advance the mechanistic understanding of coupled hydrological and ecological processes in river corridors. The studied river reach comprised the following three functional processing zones (FPZ) representing a lateral successional gradient with decreasing hydrological connectivity (i.e. decreasing flooding frequency and duration). (i) The grass zone developed naturally on a gravel bar after restoration of the channelized river section (mainly colonized by canary reed grass Phalaris arundinacae). The soil is composed of up to 80 cm thick fresh sediments trapped and stabilized by the grass roots. (ii) The bush zone is composed of young willow trees (Salix viminalis) planted during restoration to stabilize older overbank deposits. (iii) The mixed forest is a mature riparian hardwood forest developed on older overbank sediments with ash and maple as dominant trees. The study period was between April and October 2009 including two flood events in June and July. The first flood inundated the grass zone and lower part of the willow bush while the second bigger flood swept through all the FPZs. Topsoil samples were taken from four spatial replicates in each FPZ mostly biweekly and with higher frequency following the floods. Potential denitrification was measured as

  8. Caterpillars selected for large body size and short development time are more susceptible to oxygen-related stress

    PubMed Central

    Harrison, Jon F; Cease, Arianne J; VandenBrooks, John M; Albert, Todd; Davidowitz, Goggy

    2013-01-01

    Recent studies suggest that higher growth rates may be associated with reduced capacities for stress tolerance and increased accumulated damage due to reactive oxygen species. We tested the response of Manduca sexta (Sphingidae) lines selected for large or small body size and short development time to hypoxia (10 kPa) and hyperoxia (25, 33, and 40 kPa); both hypoxia and hyperoxia reduce reproduction and oxygen levels over 33 kPa have been shown to increase oxidative damage in insects. Under normoxic (21 kPa) conditions, individuals from the large-selected (big-fast) line were larger and had faster growth rates, slightly longer developmental times, and reduced survival rates compared to individuals from a line selected for small size (small-fast) or an unselected control line. Individuals from the big-fast line exhibited greater negative responses to hyperoxia with greater reductions in juvenile and adult mass, growth rate, and survival than the other two lines. Hypoxia generally negatively affected survival and growth/size, but the lines responded similarly. These results are mostly consistent with the hypothesis that simultaneous acquisition of large body sizes and short development times leads to reduced capacities for coping with stressful conditions including oxidative damage. This result is of particular importance in that natural selection tends to decrease development time and increase body size. PMID:23762517

  9. Dynamic force matching: Construction of dynamic coarse-grained models with realistic short time dynamics and accurate long time dynamics

    NASA Astrophysics Data System (ADS)

    Davtyan, Aram; Voth, Gregory A.; Andersen, Hans C.

    2016-12-01

    We recently developed a dynamic force matching technique for converting a coarse-grained (CG) model of a molecular system, with a CG potential energy function, into a dynamic CG model with realistic dynamics [A. Davtyan et al., J. Chem. Phys. 142, 154104 (2015)]. This is done by supplementing the model with additional degrees of freedom, called "fictitious particles." In that paper, we tested the method on CG models in which each molecule is coarse-grained into one CG point particle, with very satisfactory results. When the method was applied to a CG model of methanol that has two CG point particles per molecule, the results were encouraging but clearly required improvement. In this paper, we introduce a new type (called type-3) of fictitious particle that exerts forces on the center of mass of two CG sites. A CG model constructed using type-3 fictitious particles (as well as type-2 particles previously used) gives a much more satisfactory dynamic model for liquid methanol. In particular, we were able to construct a CG model that has the same self-diffusion coefficient and the same rotational relaxation time as an all-atom model of liquid methanol. Type-3 particles and generalizations of it are likely to be useful in converting more complicated CG models into dynamic CG models.

  10. Acousto-Optic Tunable Filter for Time-Domain Processing of Ultra-Short Optical Pulses,

    DTIC Science & Technology

    The application of acousto - optic tunable filters for shaping of ultra-fast pulses in the time domain is analyzed and demonstrated. With the rapid...advance of acousto - optic tunable filter (AOTF) technology, the opportunity for sophisticated signal processing capabilities arises. AOTFs offer unique

  11. Performance impact on nuclear thermal propulsion of piloted Mars missions with short transit times

    NASA Technical Reports Server (NTRS)

    Wickenheiser, T. J.; Gessner, K. S.; Alexander, S. W.

    1991-01-01

    The requirements of nuclear thermal propulsion (NTP) are examined with respect to a specific mission scenario derived from Stafford Committee recommendations. The recommended mission scenario is a split/sprint opposition mission which includes a piloted vehicle and a cargo vehicle, and the baseline mission is developed from a reference trajectory. Key mision parameters are developed from the baseline mission, including engine-thrust levels, mission opportunity, and engine burn-time requirements. The impact of engine failure is also considered in terms of burn-time requirements, and other mission-performance issues considered include propulsion-technology assumptions, triple-perigee earth-departure burns, and Mars parking-orbit selection. The engine requirements call for a 50-75-klb engine-thrust level, maximum single burn time of 0.6 hours, and a maximum total-mission burn time of 1.7 hours. For a crew of 6, a 475-day total-mission trip with a 90-day stay at Mars is possible.

  12. Short-time effect of heavy metals upon microbial community activity.

    PubMed

    Wang, Fei; Yao, Jun; Si, Yang; Chen, Huilun; Russel, Mohammad; Chen, Ke; Qian, Yiguang; Zaray, Gyula; Bramanti, Emilia

    2010-01-15

    Microcalorimetry was applied to assess and compare the toxic effect of heavy metals, such as As, Cu, Cd, Cr, Co, Pb and Zn, on the soil microbial activities and community. About 1.0 g soil spiked 5.0mg glucose and 5.0mg ammonium sulfate, the microbial activities were recorded as power-time curves, and their indices, microbial growth rate constant k, total heat evolution Q(T), metabolic enthalpy Delta H(met) and mass specific heat rate J(Q/S), were calculated. Comparing these thermodynamic parameters associated with growth yield, a general order of toxicity to the soil was found to be Cr>Pb>As>Co>Zn>Cd>Cu. When soil was exposed to heavy metals, the amount of bacteria and fungi decreased with the incubation time, and the bacterial number diminished sharply. It illustrates that fungi are more tolerant, and bacteria-fungi ratio would be altered under metal stress. To determine the status of the glucose consumed, a glucose biosensor with eggshell membrane was used to measure the remaining glucose in soil sample. Results showed that the time at which glucose was consumed completely was agreed with the microcalorimetric time to a large extent, and depended on the toxicity of heavy metals as well.

  13. Short-term prediction of solar irradiance using time-series analysis

    SciTech Connect

    Chowdhury, B.H. . Dept. of Electrical Engineering)

    1990-01-01

    A new statistical model for solar irradiance prediction is described. The method makes use of the atmospheric parameterizations as well as a time-series model to forecast a sequence of global irradiance in the 3--10 min time frame. A survey of some of the prominent research of the recent past reveals a definite lack of irradiance models that approach subhourly intervals, especially in the range mentioned. In this article, accurate parameterizations of atmospheric phenomena are used in a prewhitening process so that a time-series model may be used effectively to forecast irradiance components up to an hour in advance in the 3--10 min time intervals. The model requires only previous global horizontal irradiance measurement at a site. Results show that when compared with actual data on two locations in the southeaster United States, the forecasts are quite accurate, and the model is site-independent. Under some instances, forecasts may be inaccurate when there are sudden transitional changes in the cloud cover moving across the sun. In order for the proposed irradiance model to predict such transitional changes correctly, frequent forecast updates become necessary.

  14. Short Time-Scale Sensory Coding in S1 during Discrimination of Whisker Vibrotactile Sequences

    PubMed Central

    Miyashita, Toshio; Lee, Daniel J.; Smith, Katherine A.; Feldman, Daniel E.

    2016-01-01

    Rodent whisker input consists of dense microvibration sequences that are often temporally integrated for perceptual discrimination. Whether primary somatosensory cortex (S1) participates in temporal integration is unknown. We trained rats to discriminate whisker impulse sequences that varied in single-impulse kinematics (5–20-ms time scale) and mean speed (150-ms time scale). Rats appeared to use the integrated feature, mean speed, to guide discrimination in this task, consistent with similar prior studies. Despite this, 52% of S1 units, including 73% of units in L4 and L2/3, encoded sequences at fast time scales (≤20 ms, mostly 5–10 ms), accurately reflecting single impulse kinematics. 17% of units, mostly in L5, showed weaker impulse responses and a slow firing rate increase during sequences. However, these units did not effectively integrate whisker impulses, but instead combined weak impulse responses with a distinct, slow signal correlated to behavioral choice. A neural decoder could identify sequences from fast unit spike trains and behavioral choice from slow units. Thus, S1 encoded fast time scale whisker input without substantial temporal integration across whisker impulses. PMID:27574970

  15. 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…

  16. Short communication: Timing of first milking affects serotonin (5-HT) concentrations.

    PubMed

    Laporta, J; Gross, J J; Crenshaw, T D; Bruckmaier, R M; Hernandez, L L

    2014-05-01

    Hormonal signals differentially regulate the timing of parturition, as well lactogenesis and, potentially, colostrum formation in the mammary gland. Non-neuronal serotonin (5-HT) is a homeostatic regulator of the mammary gland. In the current study, we manipulated the timing of first milking to investigate its effects on serum 5-HT and calcium concentrations in the maternal and calf circulation, as well as in colostrum. Twenty-three cows were randomly assigned to a control (CON; n=10) group, milked for the first time at 4h postcalving, or a treatment (TRT; n=13) group, milked for the first time approximately 1 d before calving in addition to 4h postcalving. Maternal blood samples were collected for 4 d precalving, 3 times daily, and 1 blood sample was taken 4h postcalving. Calf blood samples were collected 4 (before first colostrum feeding) and 12h after birth, and at 3 wk of age. Calves from both treatments were fed colostrum from their respective mothers. Serum 5-HT concentrations were greater in CON cows and decreased significantly in TRT cows after milking was initiated precalving (951 vs. 524 ± 111 ng/mL, respectively). Cow serum calcium concentrations were affected by time, beginning to decrease 1 d precalving until 4h postcalving, but this drop in serum calcium was more pronounced in TRT cows. Serum 5-HT and calcium concentrations were negatively correlated (r=-0.57) for the CON cows and positively correlated (r=0.6) for the TRT cows. Maternal calcium and 5-HT decreased similarly due to precalving milking. Calcium and 5-HT concentrations were greater in colostrum collected from TRT cows milked precalving. Overall, calves had higher circulating 5-HT concentrations than cows, and calves born to TRT cows had increased 5-HT concentrations compared with the CON. Precalving milking could affect 5-HT synthesis within the mammary gland and therefore affect maternal 5-HT and calcium concentrations. Further research is needed in ruminants to assess the extent of 5-HT

  17. Synthesis of NaP zeolite at room temperature and short crystallization time by sonochemical method.

    PubMed

    Pal, Pameli; Das, Jugal K; Das, Nandini; Bandyopadhyay, Sibdas

    2013-01-01

    NaP zeolite nano crystals were synthesized by sonochemical method at room temperature with crystallization time of 3h. For comparison, to insure the effect of sonochemical method, the hydrothermal method at conventional synthesis condition, with same initial sol composition was studied. NaP zeolites are directly formed by ultrasonic treatment without the application of autogenous pressure and also hydrothermal treatment. The effect of ultrasonic energy and irradiation time showed that with increasing sonication energy, the crystallinity of the powders decreased but phase purity remain unchanged. The synthesized powders were characterized by XRD, IR, DTA TGA, FESEM, and TEM analysis. FESEM images revealed that 50 nm zeolite crystals were formed at room temperature by using sonochemical method. However, agglomerated particles having cactus/cabbage like structure was obtained by sonochemical method followed by hydrothermal treatment. In sonochemical process, formation of cavitation and the collapsing of bubbles produced huge energy which is sufficient for crystallization of zeolite compared to that supplied by hydrothermal process for conventional synthesis. With increasing irradiation energy and time, the crystallinity of the synthesized zeolite samples increased slightly.

  18. Short-Term Dispersal Response of an Endangered Australian Lizard Varies with Time of Year

    PubMed Central

    Ebrahimi, Mehregan; Bull, C. Michael

    2014-01-01

    Dispersal is an important component in the demography of animal populations. Many animals show seasonal changes in their tendency to disperse, reflecting changes in resource availability, mating opportunities, or in population age structure at the time when new offspring enter the population. Understanding when and why dispersal occurs can be important for the management of endangered species. The pygmy bluetongue lizard is an endangered Australian species that occupies and defends single burrow refuges for extended periods of time, rarely moving far from the burrow entrance. However, previous pitfall trapping data have suggested movement of adult males in spring and of juveniles in autumn of each year. In the current study we compared behaviours of adult lizards each month, over the spring-summer activity period over two consecutive field seasons, to provide deeper understanding of the seasonal dispersal pattern. We released adult pygmy bluetongue lizards into a central area, provided with artificial burrows, within large enclosures, and monitored the behaviour and movements of the released lizards over a four day period. There was a consistent decline in time spent basking, amount of movement around burrow entrances, and rates of dispersal from the central release area from early spring to late summer. Results could be relevant to understanding and managing natural populations and for any translocation attempts of this endangered lizard species. PMID:25147949

  19. Short-term dispersal response of an endangered Australian lizard varies with time of year.

    PubMed

    Ebrahimi, Mehregan; Bull, C Michael

    2014-01-01

    Dispersal is an important component in the demography of animal populations. Many animals show seasonal changes in their tendency to disperse, reflecting changes in resource availability, mating opportunities, or in population age structure at the time when new offspring enter the population. Understanding when and why dispersal occurs can be important for the management of endangered species. The pygmy bluetongue lizard is an endangered Australian species that occupies and defends single burrow refuges for extended periods of time, rarely moving far from the burrow entrance. However, previous pitfall trapping data have suggested movement of adult males in spring and of juveniles in autumn of each year. In the current study we compared behaviours of adult lizards each month, over the spring-summer activity period over two consecutive field seasons, to provide deeper understanding of the seasonal dispersal pattern. We released adult pygmy bluetongue lizards into a central area, provided with artificial burrows, within large enclosures, and monitored the behaviour and movements of the released lizards over a four day period. There was a consistent decline in time spent basking, amount of movement around burrow entrances, and rates of dispersal from the central release area from early spring to late summer. Results could be relevant to understanding and managing natural populations and for any translocation attempts of this endangered lizard species.

  20. Four-dimensional noise reduction using the time series of medical computed tomography datasets with short interval times: a static-phantom study

    PubMed Central

    Kono, Atsushi K.; Tani, Wakiko; Suehiro, Erina; Negi, Noriyuki; Takahashi, Satoru; Sugimura, Kazuro

    2016-01-01

    Backgrounds. This study examines the hypothesis that four-dimensional noise reduction (4DNR) with short interval times reduces noise in cardiac computed tomography (CCT) using “padding” phases. Furthermore, the capability of reducing the reduction dose in CCT using this post-processing technique was assessed. Methods. Using base and quarter radiation doses for CCT (456 and 114 mAs/rot with 120 kVp), a static phantom was scanned ten times with retrospective electrocardiogram gating, and 4DNR with short interval times (50 ms) was performed using a post-processing technique. Differences in the computed tomography (CT) attenuation, contrast-to-noise ratio (CNR) and spatial resolution with modulation transfer function in each dose image obtained with and without 4DNR were assessed by conducting a Tukey–Kramer’s test and non-inferiority test. Results. For the base dose, by using 4DNR, the CNR was improved from 1.18 ± 0.15 to 2.08 ± 0.20 (P = 0.001), while the CT attenuation and spatial resolution of the image of 4DNR did not were significantly inferior to those of reference image (P < 0.001). CNRs of the quarter-dose image in 4DNR also improved to 1.28 ± 0.11, and were not inferior to those of the non-4DNR images of the base dose (P < 0.001). Conclusions. 4DNR with short interval times significantly reduced noise. Furthermore, applying this method to CCT would have the potential of reducing the radiation dose by 75%, while maintaining a similar image noise level. PMID:26893966

  1. Identifying monomer phases and cluster phases in lysozyme solutions by studying the temperature dependence of the short-time dynamics

    SciTech Connect

    Baglioni, P; Chen, Wei-Ren; Falus, Peter; Faraone, Antonio; Fratini, Emiliano; Hong, Kunlun; Liu, Yun; Porcar, L.

    2012-01-01

    Recently experiments that combine both small angle neutron scattering (SANS) and Neutron Spin Echo (NSE) have demonstrated that dynamic clusters can form in concentrated lysozyme solutions when there is a right combination of a short-ranged attraction and a long-ranged electrostatic repulsion. In this paper, we study the temperature effect on the dynamic cluster formation and try to pinpoint the transition concentration from a monomer phase to a cluster phase. Interestingly at even a relatively high concentration (10 % mass fraction), despite the significant change of 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. This is interpreted due to the fact that there is no cluster formation at this condition. However, at larger concentrations such as 17.5 % and 22.5 % mass fraction, we show that the average hydrodynamic radius increase significantly and causes a large decrease of the normalized self-diffusion coefficient when the temperature is changed from 25 oC to 5 oC indicating the formation of dynamic clusters in solution.

  2. Effects of time-of-day and partial sleep deprivation on short-term maximal performances of judo competitors.

    PubMed

    Souissi, Nizar; Chtourou, Hamdi; Aloui, Asma; Hammouda, Omar; Dogui, Mohamed; Chaouachi, Anis; Chamari, Karim

    2013-09-01

    This study assessed the effects of partial sleep deprivation on short-term maximal performances of judokas in the morning and afternoon of the following day. In a randomized design, 12 judokas completed the maximal voluntary contraction, the handgrip, and the Wingate tests before and after a judo combat. Measurements were performed at 09:00 and 16:00 hours after a reference-normal sleep night and 2 conditions of 4-hour partial sleep deprivation timed at the beginning (SDB) or at the end of the night (SDE). The results showed that muscle power and strength were significantly higher at 16:00 than 09:00 hours (p < 0.05). These diurnal variations disappeared after SDB and SDE and after the combat. In addition, SDE resulted in significant decreases of short-term maximal performance in the afternoon (p < 0.01). In conclusion, SDE decreased muscle strength and power at 16:00 hours and, therefore, might have blunted the diurnal variations of short-term maximal exercise. Thus, early rising is more detrimental than late bedtime to muscle strength and power for judo athletes when competitions are scheduled in the afternoon hours.

  3. Using Adiabatic Inversion Pulses for Long-T2 Suppression in Ultra-short Echo Time (UTE) Imaging

    PubMed Central

    Larson, Peder E. Z.; Conolly, Steven M.; Pauly, John M.; Nishimura, Dwight G.

    2010-01-01

    Ultra-short echo time (UTE) imaging is a technique that can visualize tissues with sub-millisecond T2 values that have little or no signal in conventional MRI techniques. The short-T2 tissues, which include tendons, menisci, calcifications, and cortical bone, are often obscured by long-T2 tissues. This paper introduces a new method of long-T2 component suppression based on adiabatic inversion pulses that significantly improves the contrast of short-T2 tissues. Narrow bandwidth inversion pulses are used to selectively invert only long-T2 components. These components are then suppressed by combining images prepared with and without inversion pulses. Fat suppression can be incorporated by combining images with the pulses applied on the fat and water resonances. Scaling factors must be used in the combination to compensate for relaxation during the preparation pulses. The suppression is insensitive to RF inhomogeneities because it uses adiabatic inversion pulses. Simulations and phantom experiments demonstrate the adiabatic pulse contrast and how the scaling factors are chosen. In vivo 2D UTE images in the ankle and lower leg show excellent, robust long-T2 suppression for visualization of cortical bone and tendons. PMID:17969119

  4. 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 3×system. 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 μg/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

  5. Short-term time course of liver metabolic response to acute handling stress in rainbow trout, Oncorhynchus mykiss.

    PubMed

    López-Patiño, Marcos A; Hernández-Pérez, Juan; Gesto, Manuel; Librán-Pérez, Marta; Míguez, Jesús M; Soengas, José L

    2014-02-01

    To elucidate the short-term time-course of liver metabolic response in rainbow trout to acute handling stress we subjected rainbow trout to 5min chasing and obtained samples 0 to 480min post-stress. Levels of cortisol, glucose and lactate were measured in plasma, whereas metabolite levels, enzyme activities, mRNA abundance of parameters related to energy metabolism, and glucocorticoid receptors were assessed in liver. Acute stress affected many parameters related to energy metabolism, with most of them turning back to normal levels after 480min. In general, the present results support the existence of two stages in the short-term time-course of metabolic response to handling stress. A first stage occurring few minutes post-stress (15-45min), was characterized by increased mobilization of liver glycogen resulting in increased production of endogenous glucose, reduced use of exogenous glucose and reduced lipogenic potential. A second stage, occurring 60-120min post-stress onwards was characterized by the recovery of liver glycogen levels, the increased capacity of liver for releasing glucose, and the recovery of lipogenic capacity whereas no changes were noted in gluconeogenic potential, which probably needs longer time periods to become enhanced.

  6. Impact of Short-Stay Urethroplasty on Health-Related Quality of Life and Patient's Perception of Timing of Discharge.

    PubMed

    Okafor, Henry; Nikolavsky, Dmitriy

    2015-01-01

    Objective. To evaluate health-related quality of life in patients after a short-stay or outpatient urethroplasty. Methods. Over a 2-year period a validated health-related quality-of-life questionnaire, EuroQol (EQ-5D), was administered to all patients after urethroplasty. Postoperatively patients were offered to be sent home immediately or to stay overnight. Within 24 hours after discharge they were assessed for mobility, self-care, usual activities, pain or discomfort, and anxiety and depression. An additional question assessing timing of discharge was added to the survey. Clinical and operative characteristics were examined. Results. Forty-eight patients after anterior urethroplasty completed the survey. Mean age and mean stricture length were 51.6 years (21-78) and 60 mm (5-200 mm), respectively. Most etiologies were idiopathic (50% n = 24), trauma (19%, n = 9), and iatrogenic (19%, n = 9). Forty-one patients (85%) stayed overnight, while 7 patients (15%) chose to be discharged the same day. Overall, ninety-six percent were discharged within 23 hours of surgery. In the short-stay and the outpatient cohorts, 90% and 86%, respectively, felt they were discharged on time. No patient reported a severe problem with postoperative pain or mobility. Conclusions. The majority of patients discharged soon after their procedure felt that discharge timing was appropriate and their health-related quality of life was only minimally affected.

  7. Impact of Short-Stay Urethroplasty on Health-Related Quality of Life and Patient's Perception of Timing of Discharge

    PubMed Central

    Okafor, Henry; Nikolavsky, Dmitriy

    2015-01-01

    Objective. To evaluate health-related quality of life in patients after a short-stay or outpatient urethroplasty. Methods. Over a 2-year period a validated health-related quality-of-life questionnaire, EuroQol (EQ-5D), was administered to all patients after urethroplasty. Postoperatively patients were offered to be sent home immediately or to stay overnight. Within 24 hours after discharge they were assessed for mobility, self-care, usual activities, pain or discomfort, and anxiety and depression. An additional question assessing timing of discharge was added to the survey. Clinical and operative characteristics were examined. Results. Forty-eight patients after anterior urethroplasty completed the survey. Mean age and mean stricture length were 51.6 years (21–78) and 60 mm (5–200 mm), respectively. Most etiologies were idiopathic (50% n = 24), trauma (19%, n = 9), and iatrogenic (19%, n = 9). Forty-one patients (85%) stayed overnight, while 7 patients (15%) chose to be discharged the same day. Overall, ninety-six percent were discharged within 23 hours of surgery. In the short-stay and the outpatient cohorts, 90% and 86%, respectively, felt they were discharged on time. No patient reported a severe problem with postoperative pain or mobility. Conclusions. The majority of patients discharged soon after their procedure felt that discharge timing was appropriate and their health-related quality of life was only minimally affected. PMID:26494996

  8. Five-Kilometers Time Trial: Preliminary Validation of a Short Test for Cycling Performance Evaluation

    PubMed Central

    Dantas, Jose Luiz; Pereira, Gleber; Nakamura, Fabio Yuzo

    2015-01-01

    Background: The five-kilometer time trial (TT5km) has been used to assess aerobic endurance performance without further investigation of its validity. Objectives: This study aimed to perform a preliminary validation of the TT5km to rank well-trained cyclists based on aerobic endurance fitness and assess changes of the aerobic endurance performance. Materials and Methods: After the incremental test, 20 cyclists (age = 31.3 ± 7.9 years; body mass index = 22.7 ± 1.5 kg/m2; maximal aerobic power = 360.5 ± 49.5 W) performed the TT5km twice, collecting performance (time to complete, absolute and relative power output, average speed) and physiological responses (heart rate and electromyography activity). The validation criteria were pacing strategy, absolute and relative reliability, validity, and sensitivity. Sensitivity index was obtained from the ratio between the smallest worthwhile change and typical error. Results: The TT5km showed high absolute (coefficient of variation < 3%) and relative (intraclass coefficient correlation > 0.95) reliability of performance variables, whereas it presented low reliability of physiological responses. The TT5km performance variables were highly correlated with the aerobic endurance indices obtained from incremental test (r > 0.70). These variables showed adequate sensitivity index (> 1). Conclusions: TT5km is a valid test to rank the aerobic endurance fitness of well-trained cyclists and to differentiate changes on aerobic endurance performance. Coaches can detect performance changes through either absolute (± 17.7 W) or relative power output (± 0.3 W.kg-1), the time to complete the test (± 13.4 s) and the average speed (± 1.0 km.h-1). Furthermore, TT5km performance can also be used to rank the athletes according to their aerobic endurance fitness. PMID:26448846

  9. Design Study for a Multi-Reflection Time-of-Flight Mass Spectrograph for Very Short Lived Nuclei

    NASA Astrophysics Data System (ADS)

    Yoon, Jin Woo; Park, Young-Ho; Im, Kang-Bin; Kim, Gi Dong; Kim, Yong Kyun

    The multi-reflection time-of-flight mass spectrometer (MR-TOF-MS) has been designed for the high precision mass measurement system in RAON accelerator facility, which will be constructed in Korea. Mirror-electrode potentials were numerically optimized by Nelder-Mead algorithm. The temporal spread and the mass-resolving power were calculated for the 132Sn+ ions with an energy spread of 20 eV and an emittance of 3 π mm mrad; the mass resolving power over 105 was achieved. MR-TOF-MS will be used for the isobar separation and the mass measurement for very short-lived isotopes.

  10. Antimicrobial and antiviral effect of high-temperature short-time (HTST) pasteurization applied to human milk.

    PubMed

    Terpstra, Fokke G; Rechtman, David J; Lee, Martin L; Hoeij, Klaske Van; Berg, Hijlkeline; Van Engelenberg, Frank A C; Van't Wout, Angelica B

    2007-03-01

    In the United States, concerns over the transmission of infectious diseases have led to donor human milk generally being subjected to pasteurization prior to distribution and use. The standard method used by North American milk banks is Holder pasteurization (63 degrees C for 30 minutes). The authors undertook an experiment to validate the effects of a high-temperature short-time (HTST) pasteurization process (72 degrees C for 16 seconds) on the bioburden of human milk. It was concluded that HTST is effective in the elimination of bacteria as well as of certain important pathogenic viruses.

  11. 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.

  12. Short residence time hydropyrolysis of coal. Technical progress report, 1 January-31 March 1980

    SciTech Connect

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

    1980-01-01

    This report sets forth the current status of our efforts to model the hydropyrolysis process on the scale of a single coal particle. Several oversimplifications of the original model have been identified and the more general analysis begun. As emphasized in the literature, the effect of time-temperature history, or nonisothermal reaction conditions, appears to be important and is being incorporated into the model. An increased internal pressure due to the restricted escape of volatiles can increase the rate of deposition and also cause the swelling of plastic coal particles. Our efforts reported here should lead to realistic descriptions of these processes.

  13. Change Detection in a Short Time Sequence of Polarimetric C-Band SAR Data

    NASA Astrophysics Data System (ADS)

    Nielsen, Allan Aasbjerg; Conradsen, Knut; Skriver, Henning

    2016-08-01

    Based on an omnibus likelihood ratio test statistic for the equality of several variance-covariance matrices following the complex Wishart distribution and a factorization of this test statistic with associated p-values, change analysis in a time series of multilook, polarimetric SAR data in the covariance matrix representation is carried out. The omnibus test statistic and its factorization detect if and when change(s) occur. The technique is demonstrated on airborne EMISAR C-band data but may be applied to ALOS, COSMO-SkyMed, RadarSat-2 Sentinel-1, TerraSAR-X, and Yaogan data also.

  14. Time Dependence of Material Properties of Polyethylene Glycol Hydrogels Chain Extended with Short Hydroxy Acid Segments

    PubMed Central

    Barati, Danial; Moeinzadeh, Seyedsina; Karaman, Ozan; Jabbari, Esmaiel

    2014-01-01

    The objective of this work was to investigate the effect of chemical composition and segment number (n) on gelation, stiffness, and degradation of hydroxy acid-chain-extended star polyethylene glycol acrylate (SPEXA) gels. The hydroxy acids included glycolide (G,), L-lactide (L), p-dioxanone (D) and -caprolactone (C). Chain-extension generated water soluble macromers with faster gelation rates, lower sol fractions, higher compressive moduli, and a wide-ranging degradation times when crosslinked into a hydrogel. SPEGA gels with the highest fraction of inter-molecular crosslinks had the most increase in compressive modulus with n whereas SPELA and SPECA had the lowest increase in modulus. SPEXA gels exhibited a wide range of degradation times from a few days for SPEGA to a few weeks for SPELA, a few months for SPEDA, and many months for SPECA. Marrow stromal cells and endothelial progenitor cells had the highest expression of vasculogenic markers when co-encapsulated in the faster degrading SPELA gel. PMID:25267858

  15. Improved nutrient removal using in situ continuous on-line sensors with short response time.

    PubMed

    Ingildsen, P; Wendelboe, H

    2003-01-01

    Nutrient sensors that can be located directly in the activated sludge processes are gaining in number at wastewater treatment plants. The in situ location of the sensors means that they can be located close to the processes that they aim to control and hence are perfectly suited for automatic process control. Compared to the location of automatic analysers in the effluent from the sedimentation reactors the in situ location means a large reduction in the response time. The settlers typically work as a first-order delay on the signal with a retention time in the range of 4-12 hours depending on the size of the settlers. Automatic process control of the nitrogen and phosphorus removal processes means that considerable improvements in the performance of aeration, internal recirculation, carbon dosage and phosphate precipitation dosage can be reached by using a simple control structure as well as simple PID controllers. The performance improvements can be seen in decreased energy and chemicals consumption and less variation in effluent concentrations of ammonium, total nitrogen and phosphate. Simple control schemes are demonstrated for the pre-denitrification and the post precipitation system by means of full-scale plant experiments and model simulations.

  16. A short essay on quantum black holes and underlying noncommutative quantized space-time

    NASA Astrophysics Data System (ADS)

    Tanaka, Sho

    2017-01-01

    We emphasize the importance of noncommutative geometry or Lorenz-covariant quantized space-time towards the ultimate theory of quantum gravity and Planck scale physics. We focus our attention on the statistical and substantial understanding of the Bekenstein-Hawking area-entropy law of black holes in terms of the kinematical holographic relation (KHR). KHR manifestly holds in Yang’s quantized space-time as the result of kinematical reduction of spatial degrees of freedom caused by its own nature of noncommutative geometry, and plays an important role in our approach without any recourse to the familiar hypothesis, so-called holographic principle. In the present paper, we find a unified form of KHR applicable to the whole region ranging from macroscopic to microscopic scales in spatial dimension d  =  3. We notice a possibility of nontrivial modification of area-entropy law of black holes which becomes most remarkable in the extremely microscopic system close to Planck scale.

  17. The era of comparable life expectancy between thalassaemia major and intermedia: Is it time to revisit the major-intermedia dichotomy?

    PubMed

    Vitrano, Angela; Calvaruso, Giuseppina; Lai, Eliana; Colletta, Grazia; Quota, Alessandra; Gerardi, Calogera; Concetta Rigoli, Luciana; Pitrolo, Lorella; Cuccia, Liana; Gagliardotto, Francesco; Filosa, Aldo; Caruso, Vincenzo; Argento, Crocetta; Campisi, Saveria; Rizzo, Michele; Prossomariti, Luciano; Fidone, Carmelo; Fustaneo, Maria; Di Maggio, Rosario; Maggio, Aurelio

    2017-01-01

    In the last few decades, the life expectancy of regularly transfused β-thalassaemia major (TM) patients has dramatically improved following the introduction of safe transfusion practices, iron chelation therapy, aggressive treatment of infections and improved management of cardiac complications. How such changes, especially those attributed to the introduction of iron chelation therapy, improved the survival of TM patients to approach those with β-thalassaemia intermedia (TI) remains unknown. Three hundred and seventy-nine patients with TM (n = 284, dead 40) and TI (n = 95, dead 13) were followed retrospectively since birth until 30 June 2015 or death. Kaplan-Meir curves showed statistically significant differences in TM and TI survival (P < 0·0001) before the introduction of iron chelation in 1965, which were no longer apparent after that date (P = 0·086), reducing the Hazard Ratio of death in TM compared to TI from 6·8 [95% confidence interval (CI) 2·6-17·5] before 1965 to 2·8 (95% CI 0·8-9·2). These findings suggest that, in the era of iron chelation therapy and improved survival for TM, the major-intermedia dichotomy needs to be revisited alongside future directions in general management and prevention for both conditions.

  18. Short-time Fourier transform method for online glass ream inspection

    NASA Astrophysics Data System (ADS)

    Li, Anding; Chen, Youping; Xie, Jingming

    2016-08-01

    In the float glass defect inspection system based on machine vision, the common defects can be detected and classified correctly. However, the online glass ream inspection is still a problem to be solved, and the accuracy cannot fulfill the requirement of glass grading. As the glass ream is a rather slight optical distortion in most cases, it should be amplified so that it can be checked out easily. A Moiré method based on the theory of superposition shadow is proposed, which can magnify the distortion effectively without increasing the system complexity, and a STFT method is presented to analyze the distortion according to the characteristics of Moiré fringe pattern. With this method, the vision interference angle of glass ribbon can be calculated out accurately in real time, which makes it suitable for online glass ream inspection.

  19. Sleep benefit in Parkinson's disease is associated with short sleep times.

    PubMed

    Sherif, Eskender; Valko, Philipp O; Overeem, Sebastiaan; Baumann, Christian R

    2014-01-01

    Sleep benefit in Parkinson's disease is characterized by restoration of mobility upon awakening from sleep and prior to drug intake. With this study, we aimed at assessing clinical and nocturnal sleep correlates of this phenomenon. We recorded motor and non-motor symptoms in 131 Parkinson patients with and without sleep benefit, as assessed by questionnaires. Polysomnography recordings were performed in 60 of these patients. Thirty-nine Parkinson patients (30%) reported sleep benefit. Motor symptoms, measures of sleepiness, fatigue, depression, anxiety, sleep-wake disorders, and dopaminergic treatment were not associated with sleep benefit, and most polysomnography measures were similar between both groups. However, Parkinson patients with sleep benefit had shorter total sleep times and longer sleep latencies at nocturnal polysomnography. The link between the occurrence of sleep benefit and shorter nocturnal sleep in Parkinson's disease remains unclear.

  20. An automatic damage detection algorithm based on the Short Time Impulse Response Function

    NASA Astrophysics Data System (ADS)

    Auletta, Gianluca; Carlo Ponzo, Felice; Ditommaso, Rocco; Iacovino, Chiara

    2016-04-01

    Structural Health Monitoring together with all the dynamic identification techniques and damage detection techniques are increasing in popularity in both scientific and civil community in last years. The basic idea arises from the observation that spectral properties, described in terms of the so-called modal parameters (eigenfrequencies, mode shapes, and modal damping), are functions of the physical properties of the structure (mass, energy dissipation mechanisms and stiffness). Damage detection techniques traditionally consist in visual inspection and/or non-destructive testing. A different approach consists in vibration based methods detecting changes of feature related to damage. Structural damage exhibits its main effects in terms of stiffness and damping variation. Damage detection approach based on dynamic monitoring of structural properties over time has received a considerable attention in recent scientific literature. We focused the attention on the structural damage localization and detection after an earthquake, from the evaluation of the mode curvature difference. The methodology is based on the acquisition of the structural dynamic response through a three-directional accelerometer installed on the top floor of the structure. It is able to assess the presence of any damage on the structure providing also information about the related position and severity of the damage. The procedure is based on a Band-Variable Filter, (Ditommaso et al., 2012), used to extract the dynamic characteristics of systems that evolve over time by acting simultaneously in both time and frequency domain. In this paper using a combined approach based on the Fourier Transform and on the seismic interferometric analysis, an useful tool for the automatic fundamental frequency evaluation of nonlinear structures has been proposed. Moreover, using this kind of approach it is possible to improve some of the existing methods for the automatic damage detection providing stable results

  1. Short treatment time and excellent treatment outcome in accelerated hyperfractionated radiotherapy for T1 glottic cancer.

    PubMed

    Tamaki, Yukihisa; Hieda, Yoko; Yoshida, Rika; Yoshizako, Takeshi; Fuchiwaki, Takafumi; Aoi, Noriaki; Sekihara, Kazumasa; Kitajima, Kazuhiro; Kawauchi, Hideyuki; Kitagaki, Hajime; Sasaki, Ryohei; Inomata, Taisuke

    2015-11-01

    Accelerated hyperfractionated radiotherapy was performed as treatment for patients with T1 glottic cancer, and its utility was evaluated based on treatment outcomes and adverse effects. Fifty-eight men who had undergone radiotherapy were retrospectively reviewed. Tumor classification was Tis in 4 patients, T1a in 38, and T1b in 16. Histological examination revealed squamous cell carcinoma in 55 patients. Travel time from home to hospital was 0-1 hour for 24 patients, 1-2 hours for 9, and >2 hours for 25. Laser vaporization was performed prior to radiotherapy in 38 patients, and 19 patients received concurrent chemotherapy with an agent such as S-1. Patients were irradiated twice daily using an irradiation container. Most patients received a dose of 1.5 Gy/fraction up to a total of 60 Gy. The median overall treatment time was 30 days, with a median observation period of 59.6 months. A complete response was observed in all patients. The 5-year overall survival, disease-free survival, and local control rates were 97.2%, 93.2%, and 97.8%, respectively. Although grade 3 pharyngeal mucositis was observed in 2 patients, there were no other grade 3 or higher acute adverse events. As late toxicity, grade 2 laryngeal edema and grade 1 laryngeal hemorrhage were observed in 1 patient each, but no serious events such as laryngeal necrosis or laryngeal stenosis were observed. In conclusion, this treatment method brings excellent outcome and will substantially reduce the treatment duration among patients who need to stay at nearby hotels while undergoing treatment at hospitals in rural areas.

  2. Short-term forecasting of meteorological time series using Nonparametric Functional Data Analysis (NPFDA)

    NASA Astrophysics Data System (ADS)

    Curceac, S.; Ternynck, C.; Ouarda, T.

    2015-12-01

    Over the past decades, a substantial amount of research has been conducted to model and forecast climatic variables. In this study, Nonparametric Functional Data Analysis (NPFDA) methods are applied to forecast air temperature and wind speed time series in Abu Dhabi, UAE. The dataset consists of hourly measurements recorded for a period of 29 years, 1982-2010. The novelty of the Functional Data Analysis approach is in expressing the data as curves. In the present work, the focus is on daily forecasting and the functional observations (curves) express the daily measurements of the above mentioned variables. We apply a non-linear regression model with a functional non-parametric kernel estimator. The computation of the estimator is performed using an asymmetrical quadratic kernel function for local weighting based on the bandwidth obtained by a cross validation procedure. The proximities between functional objects are calculated by families of semi-metrics based on derivatives and Functional Principal Component Analysis (FPCA). Additionally, functional conditional mode and functional conditional median estimators are applied and the advantages of combining their results are analysed. A different approach employs a SARIMA model selected according to the minimum Akaike (AIC) and Bayessian (BIC) Information Criteria and based on the residuals of the model. The performance of the models is assessed by calculating error indices such as the root mean square error (RMSE), relative RMSE, BIAS and relative BIAS. The results indicate that the NPFDA models provide more accurate forecasts than the SARIMA models. Key words: Nonparametric functional data analysis, SARIMA, time series forecast, air temperature, wind speed

  3. Raman Scattering at Resonant or Near-Resonant Conditions: A Generalized Short-Time Approximation

    NASA Astrophysics Data System (ADS)

    Mohammed, Abdelsalam; Sun, Yu-Ping; Miao, Quan; Ågren, Hans; Gel'mukhanov, Faris

    2012-02-01

    We investigate the dynamics of resonant Raman scattering in the course of the frequency detuning. The dephasing in the time domain makes the scattering fast when the photon energy is tuned from the absorption resonance. This makes frequency detuning to act as a camera shutter with a regulated scattering duration and provides a practical tool of controlling the scattering time in ordinary stationary measurements. The theory is applied to resonant Raman spectra of a couple of few-mode model systems and to trans-1,3,5-hexatriene and guanine-cytosine (G-C) Watson-Crick base pairs (DNA) molecules. Besides some particular physical effects, the regime of fast scattering leads to a simplification of the spectrum as well as to the scattering theory itself. Strong overtones appear in the Raman spectra when the photon frequency is tuned in the resonant region, while in the mode of fast scattering, the overtones are gradually quenched when the photon frequency is tuned more than one vibrational quantum below the first absorption resonance. The detuning from the resonant region thus leads to a strong purification of the Raman spectrum from the contamination by higher overtones and soft modes and purifies the spectrum also in terms of avoidance of dissociation and interfering fluorescence decay of the resonant state. This makes frequency detuning a very useful practical tool in the analysis of the resonant Raman spectra of complex systems and considerably improves the prospects for using the Raman effect for detection of foreign substances at ultra-low concentrations.

  4. [Evaluation of short-time premedication with d-chlorpheniramine maleate injection for paclitaxel-induced hypersensitivity reaction].

    PubMed

    Harada, Tomohiko; Doi, Masakazu; Yamada, Yasuhiko; Akase, Tomohide

    2008-08-01

    Paclitaxel(referred to hereinafter as PTX )is used in ovarian cancer, non-small cell lung cancer, breast cancer, gastric cancer, and endometrial cancer with positive treatment result reports. However, severe allergic reactions such as decreases in blood pressure and impaired breathing occur with relatively high frequency. For the prevention of such allergic reactions, administration of a premedication composed of the three components, dexamethasone sodium phosphate injection, diphenhydramine hydrochloride tablet, and ranitidine hydrochloride injection solution(or injectable famodine), is advised in the appended documentation. Administration is difficult because, among these three components, only diphenhydramine hydrochloride is administered orally and thus must be provided through the internal medicine department. Particularly when this combined dosage is administered as outpatient chemotherapy, the doctor must prescribe diphenhydramine hydrochloride tablets, and the patient must not forget to bring them on the day in which chemotherapy is administered. Also, checks by the medical staff such as pharmacists and nurses are required, complicating the administration of this therapy further. Taking this situation into consideration, our hospital uses a short-time premedication method wherein d-Chlorpheniramine Maleate injections are substituted for diphenhydramine hydrochloride tablets, and the time required for premedication is reduced to 15 minutes. This study investigated the allergic reaction ratio to consider the safety and usefulness of the short-time premedication method used at our hospital. The chemotherapy regimens conducted for the subject patients were 9 cases of PTX+CBDCA, 6 cases of biweekly- PTX, and 5 cases of weekly-PTX. A total of 67 PTX injections were given, 15 of them being first-time administrations. The ratio of allergic/hypersensitivity reactions was 10.0%(2 cases in 20). The short-time premedication method using d-Chlorpheniramine Maleate

  5. Detrended fluctuation analysis and adaptive fractal analysis of stride time data in Parkinson's disease: stitching together short gait trials.

    PubMed

    Kirchner, Marietta; Schubert, Patric; Liebherr, Magnus; Haas, Christian T

    2014-01-01

    Variability indicates motor control disturbances and is suitable to identify gait pathologies. It can be quantified by linear parameters (amplitude estimators) and more sophisticated nonlinear methods (structural information). Detrended Fluctuation Analysis (DFA) is one method to measure structural information, e.g., from stride time series. Recently, an improved method, Adaptive Fractal Analysis (AFA), has been proposed. This method has not been applied to gait data before. Fractal scaling methods (FS) require long stride-to-stride data to obtain valid results. However, in clinical studies, it is not usual to measure a large number of strides (e.g., [Formula: see text][Formula: see text] strides). Amongst others, clinical gait analysis is limited due to short walkways, thus, FS seem to be inapplicable. The purpose of the present study was to evaluate FS under clinical conditions. Stride time data of five self-paced walking trials ([Formula: see text] strides each) of subjects with PD and a healthy control group (CG) was measured. To generate longer time series, stride time sequences were stitched together. The coefficient of variation (CV), fractal scaling exponents [Formula: see text] (DFA) and [Formula: see text] (AFA) were calculated. Two surrogate tests were performed: A) the whole time series was randomly shuffled; B) the single trials were randomly shuffled separately and afterwards stitched together. CV did not discriminate between PD and CG. However, significant differences between PD and CG were found concerning [Formula: see text] and [Formula: see text]. Surrogate version B yielded a higher mean squared error and empirical quantiles than version A. Hence, we conclude that the stitching procedure creates an artificial structure resulting in an overestimation of true [Formula: see text]. The method of stitching together sections of gait seems to be appropriate in order to distinguish between PD and CG with FS. It provides an approach to integrate FS as

  6. Detrended Fluctuation Analysis and Adaptive Fractal Analysis of Stride Time Data in Parkinson's Disease: Stitching Together Short Gait Trials

    PubMed Central

    Liebherr, Magnus; Haas, Christian T.

    2014-01-01

    Variability indicates motor control disturbances and is suitable to identify gait pathologies. It can be quantified by linear parameters (amplitude estimators) and more sophisticated nonlinear methods (structural information). Detrended Fluctuation Analysis (DFA) is one method to measure structural information, e.g., from stride time series. Recently, an improved method, Adaptive Fractal Analysis (AFA), has been proposed. This method has not been applied to gait data before. Fractal scaling methods (FS) require long stride-to-stride data to obtain valid results. However, in clinical studies, it is not usual to measure a large number of strides (e.g., strides). Amongst others, clinical gait analysis is limited due to short walkways, thus, FS seem to be inapplicable. The purpose of the present study was to evaluate FS under clinical conditions. Stride time data of five self-paced walking trials ( strides each) of subjects with PD and a healthy control group (CG) was measured. To generate longer time series, stride time sequences were stitched together. The coefficient of variation (CV), fractal scaling exponents (DFA) and (AFA) were calculated. Two surrogate tests were performed: A) the whole time series was randomly shuffled; B) the single trials were randomly shuffled separately and afterwards stitched together. CV did not discriminate between PD and CG. However, significant differences between PD and CG were found concerning and . Surrogate version B yielded a higher mean squared error and empirical quantiles than version A. Hence, we conclude that the stitching procedure creates an artificial structure resulting in an overestimation of true . The method of stitching together sections of gait seems to be appropriate in order to distinguish between PD and CG with FS. It provides an approach to integrate FS as standard in clinical gait analysis and to overcome limitations such as short walkways. PMID:24465708

  7. Revisiting Dialogues and Monologues

    ERIC Educational Resources Information Center

    Kvernbekk, Tone

    2012-01-01

    In educational discourse dialogue tends to be viewed as being (morally) superior to monologue. When we look at them as basic forms of communication, we find that dialogue is a two-way, one-to-one form and monologue is a one-way, one-to-many form. In this paper I revisit the alleged (moral) superiority of dialogue. First, I problematize certain…

  8. Clinical ethics revisited

    PubMed Central

    Singer, Peter A; Pellegrino, Edmund D; Siegler, Mark

    2001-01-01

    A decade ago, we reviewed the field of clinical ethics; assessed its progress in research, education, and ethics committees and consultation; and made predictions about the future of the field. In this article, we revisit clinical ethics to examine our earlier observations, highlight key developments, and discuss remaining challenges for clinical ethics, including the need to develop a global perspective on clinical ethics problems. PMID:11346456

  9. Mountain Rivers Revisited

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2011-12-01

    Published in 2000, the original Mountain Rivers was written to provide a concise summary of the scientific understanding of the distinct subset of rivers that gave the book its name. Spurred by developments in the field in the past decade, the book's author, Ellen Wohl, produced Mountain Rivers Revisited, an updated edition aimed at graduate students and professional researchers. In this interview, Eos talks to Wohl about steep channels, climate change, and opportunities for future research.

  10. Measuring the impact of temperature changes on the wine production in the Douro Region using the short time fourier transform.

    PubMed

    Cunha, Mário; Richter, Christian

    2012-03-01

    This paper investigates the cyclical behaviour of the wine production in Douro region during the period 1932-2008. In general, wine production is characterised by large fluctuations which are composed of short-term and/or long-term cycles. The aim of this paper is twofold: firstly, we decompose the wine production's variance in order to find the dominating production cycles, i.e we try to explain whether wine production follows more long-term or short-term cycles. In the next step, we try to explain those cycles using a dependent variable, namely the medium spring temperature (Tm_Sp) for the period 1967-2008. We estimated a Time-Varying Autoregressive Model, which could explain 75% of the production that is characterised by 4.8- and 2.5-year cycles. We use the Short Time Fourier Transform to decompose the link between wine production and temperature. When the temperature was incorporated, the R (2) increased and the Akaike criterion value was lower. Hence, Tm_Sp causes a large amount of these cycles and the wine production variation reflects this relationship. In addition to an upward trend, there is a clearly identifiable cycle around the long-term trend in production. We also show how much of the production cycle and what cycle in particular is explained by the Tm_Sp. There is a stable but not constant link between production and the Tm_Sp. In particular, the temperature is responsible for 5.2- and 2.4-year cycles which has been happening since the 1980s. The Tm_Sp can also be used as an indicator for the 4.8- and 2.5-year cycles of production. The developed model suggests that stationarity is a questionable assumption, and this means that historical distributions of wine production are going to need dynamic updating.

  11. Measuring the impact of temperature changes on the wine production in the Douro Region using the short time fourier transform

    NASA Astrophysics Data System (ADS)

    Cunha, Mário; Richter, Christian

    2012-03-01

    This paper investigates the cyclical behaviour of the wine production in Douro region during the period 1932-2008. In general, wine production is characterised by large fluctuations which are composed of short-term and/or long-term cycles. The aim of this paper is twofold: firstly, we decompose the wine production's variance in order to find the dominating production cycles, i.e we try to explain whether wine production follows more long-term or short-term cycles. In the next step, we try to explain those cycles using a dependent variable, namely the medium spring temperature (Tm_Sp) for the period 1967-2008. We estimated a Time-Varying Autoregressive Model, which could explain 75% of the production that is characterised by 4.8- and 2.5-year cycles. We use the Short Time Fourier Transform to decompose the link between wine production and temperature. When the temperature was incorporated, the R 2 increased and the Akaike criterion value was lower. Hence, Tm_Sp causes a large amount of these cycles and the wine production variation reflects this relationship. In addition to an upward trend, there is a clearly identifiable cycle around the long-term trend in production. We also show how much of the production cycle and what cycle in particular is explained by the Tm_Sp. There is a stable but not constant link between production and the Tm_Sp. In particular, the temperature is responsible for 5.2- and 2.4-year cycles which has been happening since the 1980s. The Tm_Sp can also be used as an indicator for the 4.8- and 2.5-year cycles of production. The developed model suggests that stationarity is a questionable assumption, and this means that historical distributions of wine production are going to need dynamic updating.

  12. On the Frequency of Additional Planets in Short Period Hot Jupiter Systems from Transit Timing Variations

    NASA Astrophysics Data System (ADS)

    Dittmann, Jason; Close, L.; Scuderi, L.

    2011-05-01

    The large number of hot Jupiter planets allows one to probe these systems for additional unseen planets via transit timing variations (TTVs). Even relatively small terrestrial planets, when placed in an energetically favorable mean motion resonance (MMR), can cause detectable TTVs with an amplitude of several minutes (Holman and Murray 2005, Agol et al. 2005). In an effort to discover and characterize such companions, we have embarked on a systematic study of known transiting hot Jupiters, utilizing the 1.55 meter Kuiper telescope on Mt. Bigelow to measure multiple individual transits in an observing season to within 30 second precision, and constrain the nature of any planetary companions. Here, we present current and preliminary results on this study, and show that the systems HAT-P-5, HAT- P-6, HAT-P-8, HAT-P-9, WASP-11/HAT-P-10, HAT-P-11, TrES-2, and WASP-10 do not contain small mass companions in MMRs, or moderate mass companions in close enough proximity to induce TTVs on the order of 1.5 minutes.

  13. Stress and Fatigue Management Using Balneotherapy in a Short-Time Randomized Controlled Trial

    PubMed Central

    Razbadauskas, Artūras; Sąlyga, Jonas; Martinkėnas, Arvydas

    2016-01-01

    Objective. To investigate the influence of high-salinity geothermal mineral water on stress and fatigue. Method. 180 seamen were randomized into three groups: geothermal (65), music (50), and control (65). The geothermal group was administered 108 g/L salinity geothermal water bath for 2 weeks five times a week. Primary outcome was effect on stress and fatigue. Secondary outcomes were the effect on cognitive function, mood, and pain. Results. The improvements after balneotherapy were a reduction in the number and intensity of stress-related symptoms, a reduction in pain and general, physical, and mental fatigue, and an improvement in stress-related symptoms management, mood, activation, motivation, and cognitive functions with effect size from 0.8 to 2.3. In the music therapy group, there were significant positive changes in the number of stress symptoms, intensity, mood, pain, and activity with the effect size of 0.4 to 1.1. The researchers did not observe any significant positive changes in the control group. The comparison between the groups showed that balneotherapy was superior to music therapy and no treatment group. Conclusions. Balneotherapy is beneficial for stress and fatigue reduction in comparison with music or no therapy group. Geothermal water baths have a potential as an efficient approach to diminish stress caused by working or living conditions. PMID:27051455

  14. Assessment of Transmission in Trachoma Programs over Time Suggests No Short-Term Loss of Immunity

    PubMed Central

    Liu, Fengchen; Porco, Travis C.; Ray, Kathryn J.; Bailey, Robin L.; Mkocha, Harran; Muñoz, Beatriz; Quinn, Thomas C.; Lietman, Thomas M.; West, Sheila K.

    2013-01-01

    Trachoma programs have dramatically reduced the prevalence of the ocular chlamydia that cause the disease. Some have hypothesized that immunity to the infection may be reduced because of program success in reducing the incidence of infection, and transmission may then increase. Longitudinal studies of multiple communities would be necessary to test this hypothesis. Here, we quantify transmission using an estimated basic reproduction number based on 32 communities during the first, second, and third years of an antibiotic treatment program. We found that there is little to no increase in the basic reproduction number over time. The estimated linear trend in the basic reproduction number, , was found to be −0.025 per year, 95% CI −0.167 to 0.117 per year. We are unable to find evidence supporting any loss of immunity over the course of a 3-year program. This is encouraging, as it allows the possibility that repeated mass antibiotic distributions may eliminate infection from even the most severely affected areas. PMID:23875038

  15. 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

  16. Short-term forecasting of life-threatening cardiac arrhythmias based on symbolic dynamics and finite-time growth rates

    NASA Astrophysics Data System (ADS)

    Wessel, Niels; Ziehmann, Christine; Kurths, Jürgen; Meyerfeldt, Udo; Schirdewan, Alexander; Voss, Andreas

    2000-01-01

    Ventricular tachycardia or fibrillation (VT-VF) as fatal cardiac arrhythmias are the main factors triggering sudden cardiac death. The objective of this study is to find early signs of sustained VT-VF in patients with an implanted cardioverter-defibrillator (ICD). These devices are able to safeguard patients by returning their hearts to a normal rhythm via strong defibrillatory shocks; additionally, they store the 1000 beat-to-beat intervals immediately before the onset of a life-threatening arrhythmia. We study these 1000 beat-to-beat intervals of 17 chronic heart failure ICD patients before the onset of a life-threatening arrhythmia and at a control time, i.e., without a VT-VF event. To characterize these rather short data sets, we calculate heart rate variability parameters from the time and frequency domain, from symbolic dynamics as well as the finite-time growth rates. We find that neither the time nor the frequency domain parameters show significant differences between the VT-VF and the control time series. However, two parameters from symbolic dynamics as well as the finite-time growth rates discriminate significantly both groups. These findings could be of importance in algorithms for next generation ICD's to improve the diagnostics and therapy of VT-VF.

  17. Methods for Developing Evidence Reviews in Short Periods of Time: A Scoping Review

    PubMed Central

    Abou-Setta, Ahmed M.; Jeyaraman, Maya; Attia, Abdelhamid; Al-Inany, Hesham G.; Ferri, Mauricio; Ansari, Mohammed T.; Garritty, Chantelle M.; Bond, Kenneth; Norris, Susan L.

    2016-01-01

    Introduction Rapid reviews (RR), using abbreviated systematic review (SR) methods, are becoming more popular among decision-makers. This World Health Organization commissioned study sought to summarize RR methods, identify differences, and highlight potential biases between RR and SR. Methods Review of RR methods (Key Question 1 [KQ1]), meta-epidemiologic studies comparing reliability/ validity of RR and SR methods (KQ2), and their potential associated biases (KQ3). We searched Medline, EMBASE, Cochrane Library, grey literature, and checked reference lists, used personal contacts, and crowdsourcing (e.g. email listservs). Selection and data extraction was conducted by one reviewer (KQ1) or two reviewers independently (KQ2-3). Results Across all KQs, we identified 42,743 citations through the literature searches. KQ1: RR methods from 29 organizations were reviewed. There was no consensus on which aspects of the SR process to abbreviate. KQ2: Studies comparing the conclusions of RR and SR (n = 9) found them to be generally similar. Where major differences were identified, it was attributed to the inclusion of evidence from different sources (e.g. searching different databases or including different study designs). KQ3: Potential biases introduced into the review process were well-identified although not necessarily supported by empirical evidence, and focused mainly on selective outcome reporting and publication biases. Conclusion RR approaches are context and organization specific. Existing comparative evidence has found similar conclusions derived from RR and SR, but there is a lack of evidence comparing the potential of bias in both evidence synthesis approaches. Further research and decision aids are needed to help decision makers and reviewers balance the benefits of providing timely evidence with the potential for biased findings. PMID:27930662

  18. Substitute CT generation from a single ultra short time echo MRI sequence: preliminary study

    NASA Astrophysics Data System (ADS)

    Ghose, Soumya; Dowling, Jason A.; Rai, Robba; Liney, Gary P.

    2017-04-01

    In MR guided radiation therapy planning both MR and CT images for a patient are acquired and co-registered to obtain a tissue specific HU map. Generation of the HU map directly from the MRI would eliminate the CT acquisition and may improve radiation therapy planning. In this preliminary study of substitute CT (sCT) generation, two porcine leg phantoms were scanned using a 3D ultrashort echo time (PETRA) sequence and co-registered to corresponding CT images to build tissue specific regression models. The model was created from one co-registered CT-PETRA pair to generate the sCT for the other PETRA image. An expectation maximization based clustering was performed on the co-registered PETRA image to identify the soft tissues, dense bone and air class membership probabilities. A tissue specific non linear regression model was built from one registered CT-PETRA pair dataset to predict the sCT of the second PETRA image in a two-fold cross validation schema. A complete substitute CT is generated in 3 min. The mean absolute HU error for air was 0.3 HU, bone was 95 HU, fat was 30 HU and for muscle it was 10 HU. The mean surface reconstruction error for the bone was 1.3 mm. The PETRA sequence enabled a low mean absolute surface distance for the bone and a low HU error for other classes. The sCT generated from a single PETRA sequence shows promise for the generation of fast sCT for MRI based radiation therapy planning.

  19. Does Occupational Exposure of Shahid Dastghieb International Airport Workers to Radiofrequency Radiation Affect Their Short Term Memory and Reaction Time?

    PubMed Central

    Jarideh, S.; Taeb, S.; Pishva, S. M.; Haghani, M.; Sina, S.; Mortazavi, S. A. R.; Hosseini, M. A.; Nematollahi, S.; Shokrpour, N.; Hassan Shahi, M.; Mortazavi, S. M. J.

    2015-01-01

    Background Airport workers are continuously exposed to different levels of radiofrequency microwave (RF/MW) radiation emitted by radar equipments. Radars are extensively used in military and aviation industries. Over the past several years, our lab has focused on the health effects of exposure to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and MRI. The main goal of this study was to investigate if occupational exposure of Shahid Dastghieb international airport workers to radiofrequency radiation affects their short term memory and reaction time. Methods Thirty two airport workers involved in duties at control and approach tower (21 males and 11 females), with the age range of 27-67 years old (mean age of 37.38), participated voluntary in this study. On the other hand, 29 workers (13 males, and 16 females) whose offices were in the city with no exposure history to radar systems were also participated in this study as the control group. The employees’ reaction time and short term memory were analyzed using a standard visual reaction time (VRT) test software and the modified Wechsler memory scale test, respectively. Results The mean± SD values for the reaction times of the airport employees (N=32) and the control group (N=29) were 0.45±0.12 sec and 0.46±0.17 sec, respectively.  Moreover, in the four subset tests; i.e. paired words, forward digit span, backward digit span and word recognition, the following points were obtained for the airport employees and the control group, respectively: (i) pair words test: 28.00±13.13 and 32.07±11.65, (ii) forward digit span: 8.38±1.40 and 9.03±1.32, (iii) backward digit span: 5.54±1.87 and 6.31±1.46, and (iv) word recognition: 5.73±2.36 and 6.50±1.93. These differences were not statistically significant. Conclusion The occupational exposure of the employees to the RF radiation in Shahid Dastghieb

  20. Non-Linear Dynamical Classification of Short Time Series of the Rössler System in High Noise Regimes

    PubMed Central

    Lainscsek, Claudia; Weyhenmeyer, Jonathan; Hernandez, Manuel E.; Poizner, Howard; Sejnowski, Terrence J.

    2013-01-01

    Time series analysis with delay differential equations (DDEs) reveals non-linear properties of the underlying dynamical system and can serve as a non-linear time-domain classification tool. Here global DDE models were used to analyze short segments of simulated time series from a known dynamical system, the Rössler system, in high noise regimes. In a companion paper, we apply the DDE model developed here to classify short segments of encephalographic (EEG) data recorded from patients with Parkinson’s disease and healthy subjects. Nine simulated subjects in each of two distinct classes were generated by varying the bifurcation parameter b and keeping the other two parameters (a and c) of the Rössler system fixed. All choices of b were in the chaotic parameter range. We diluted the simulated data using white noise ranging from 10 to −30 dB signal-to-noise ratios (SNR). Structure selection was supervised by selecting the number of terms, delays, and order of non-linearity of the model DDE model that best linearly separated the two classes of data. The distances d from the linear dividing hyperplane was then used to assess the classification performance by computing the area A′ under the ROC curve. The selected model was tested on untrained data using repeated random sub-sampling validation. DDEs were able to accurately distinguish the two dynamical conditions, and moreover, to quantify the changes in the dynamics. There was a significant correlation between the dynamical bifurcation parameter b of the simulated data and the classification parameter d from our analysis. This correlation still held for new simulated subjects with new dynamical parameters selected from each of the two dynamical regimes. Furthermore, the correlation was robust to added noise, being significant even when the noise was greater than the signal. We conclude that DDE models may be used as a generalizable and reliable classification tool for even small segments of noisy data. PMID

  1. Duty periods with early start times restrict the amount of sleep obtained by short-haul airline pilots.

    PubMed

    Roach, Gregory D; Sargent, Charli; Darwent, David; Dawson, Drew

    2012-03-01

    Most of the research related to human fatigue in the aviation industry has focussed on long-haul pilots, but short-haul pilots also experience elevated levels of fatigue. The aim of this study was to examine the impact of early start times on the amount of sleep obtained prior to duty and on fatigue levels at the start of duty. Seventy short-haul pilots collected data regarding their duty schedule and sleep/wake behaviour for at least two weeks. Data were collected using self-report duty/sleep diaries and wrist activity monitors. Mixed-effects regression analyses were used to examine the effects of duty start time (04:00-10:00 h) on (i) the total amount of sleep obtained in the 12h prior to the start of duty and (ii) self-rated fatigue level at the start of duty. Both analyses indicated significant main effects of duty start time. In particular, the amount of sleep obtained in the 12h prior to duty was lowest for duty periods that commenced between 04:00 and 05:00 h (i.e. 5.4h), and greatest for duty periods that commenced between 09:00 and 10:00 h (i.e. 6.6h). These data indicate that approximately 15 min of sleep is lost for every hour that the start of duty is advanced prior to 09:00 h. In addition, self-rated fatigue at the start of duty was highest for duty periods that commenced between 04:00 and 05:00 h, and lowest for duty periods that commenced between 09:00 and 10:00 h. Airlines should implement a fatigue risk management system (FRMS) for short-haul pilots required to work early-morning shifts. One component of the FRMS should be focussed on the production of 'fatigue-friendly' rosters. A second component of the FRMS should be focussed on training pilots to optimise sleep opportunities, to identify circumstances where the likelihood of fatigue is elevated, and to manage the risks associated with fatigue-related impairment.

  2. FY05 LDRD Final ReportTime-Resolved Dynamic Studies using Short Pulse X-Ray Radiation

    SciTech Connect

    Nelson, A; Dunn, J; van Buuren, T; Budil, K; Sadigh, B; Gilmer, G; Falcone, R; Lee, R; Ng, A

    2006-02-10

    Established techniques must be extended down to the ps and sub-ps time domain to directly probe product states of materials under extreme conditions. We used short pulse ({le} 1 ps) x-ray radiation to track changes in the physical properties in tandem with measurements of the atomic and electronic structure of materials undergoing fast laser excitation and shock-related phenomena. The sources included those already available at LLNL, including the picosecond X-ray laser as well as the ALS Femtosecond Phenomena beamline and the SSRL based sub-picosecond photon source (SPPS). These allow the temporal resolution to be improved by 2 orders of magnitude over the current state-of-the-art, which is {approx} 100 ps. Thus, we observed the manifestations of dynamical processes with unprecedented time resolution. Time-resolved x-ray photoemission spectroscopy and x-ray scattering were used to study phase changes in materials with sub-picosecond time resolution. These experiments coupled to multiscale modeling allow us to explore the physics of materials in high laser fields and extreme non-equilibrium states of matter. The ability to characterize the physical and electronic structure of materials under extreme conditions together with state-of-the-art models and computational facilities will catapult LLNL's core competencies into the scientific world arena as well as support its missions of national security and stockpile stewardship.

  3. Time-series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream

    NASA Astrophysics Data System (ADS)

    Duvert, C.; Stewart, M. K.; Cendón, D. I.; Raiber, M.

    2015-08-01

    A major limitation to the accurate assessment of streamwater transit time (TT) stems from the use of stable isotopes or chloride as hydrological tracers, because these tracers are blind to older contributions. Also, while catchment processes are highly non-stationary, the importance of temporal dynamics in older water TT has often been overlooked. In this study we used lumped convolution models to examine time-series of tritium, stable isotopes and chloride in rainfall, streamwater and groundwater of a catchment located in subtropical Australia. Our objectives were to assess the different contributions to streamflow and their variations over time, and to understand the relationships between streamwater TT and groundwater residence time. Stable isotopes and chloride provided consistent estimates of TT in the upstream part of the catchment. A young component to streamflow was identified that was partitioned into quickflow (mean TT ≈ 2 weeks) and discharge from the fractured igneous rocks forming the headwaters (mean TT ≈ 0.3 years). The use of tritium was beneficial for determining an older contribution to streamflow in the downstream area. The best fits were obtained for a mean TT of 16-25 years for this older groundwater component. This was significantly lower than the residence time calculated for the alluvial aquifer feeding the stream downstream (≈ 76-102 years), outlining the fact that water exiting the catchment and water stored in it had distinctive age distributions. When simulations were run separately on each tritium streamwater sample, the TT of old water fraction varied substantially over time, with values averaging 17 ± 6 years at low flow and 38 ± 15 years after major recharge events. This was interpreted as the flushing out of deeper, older waters shortly after recharge by the resulting pressure wave propagation. Overall, this study shows the usefulness of collecting tritium data in streamwater to document short-term variations in the older

  4. Time series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream

    NASA Astrophysics Data System (ADS)

    Duvert, C.; Stewart, M. K.; Cendón, D. I.; Raiber, M.

    2016-01-01

    A major limitation to the assessment of catchment transit time (TT) stems from the use of stable isotopes or chloride as hydrological tracers, because these tracers are blind to older contributions. Yet, accurately capturing the TT of the old water fraction is essential, as is the assessment of its temporal variations under non-stationary catchment dynamics. In this study we used lumped convolution models to examine time series of tritium, stable isotopes and chloride in rainfall, streamwater and groundwater of a catchment located in subtropical Australia. Our objectives were to determine the different contributions to streamflow and their variations over time, and to understand the relationship between catchment TT and groundwater residence time. Stable isotopes and chloride provided consistent estimates of TT in the upstream part of the catchment. A young component to streamflow was identified that was partitioned into quickflow (mean TT ≈ 2 weeks) and discharge from the fractured igneous rocks forming the headwaters (mean TT ≈ 0.3 years). The use of tritium was beneficial for determining an older contribution to streamflow in the downstream area. The best fits between measured and modelled tritium activities were obtained for a mean TT of 16-25 years for this older groundwater component. This was significantly lower than the residence time calculated for groundwater in the alluvial aquifer feeding the stream downstream ( ≈ 76-102 years), emphasising the fact that water exiting the catchment and water stored in it had distinctive age distributions. When simulations were run separately on each tritium streamwater sample, the TT of old water fraction varied substantially over time, with values averaging 17 ± 6 years at low flow and 38 ± 15 years after major recharge events. This counterintuitive result was interpreted as the flushing out of deeper, older waters shortly after recharge by the resulting pressure wave propagation. Overall, this study shows the

  5. Properties of quantum systems via diagonalization of transition amplitudes. II. Systematic improvements of short-time propagation.

    PubMed

    Vidanović, Ivana; Bogojević, Aleksandar; Balaz, Antun; Belić, Aleksandar

    2009-12-01

    In this paper, building on a previous analysis [I. Vidanović, A. Bogojević, and A. Belić, preceding paper, Phys. Rev. E 80, 066705 (2009)] of exact diagonalization of the space-discretized evolution operator for the study of properties of nonrelativistic quantum systems, we present a substantial improvement to this method. We apply recently introduced effective action approach for obtaining short-time expansion of the propagator up to very high orders to calculate matrix elements of space-discretized evolution operator. This improves by many orders of magnitude previously used approximations for discretized matrix elements and allows us to numerically obtain large numbers of accurate energy eigenvalues and eigenstates using numerical diagonalization. We illustrate this approach on several one- and two-dimensional models. The quality of numerically calculated higher-order eigenstates is assessed by comparison with semiclassical cumulative density of states.

  6. Analyses of kinetic glass transition in short-range attractive colloids based on time-convolutionless mode-coupling theory

    NASA Astrophysics Data System (ADS)

    Narumi, Takayuki; Tokuyama, Michio

    2017-03-01

    For short-range attractive colloids, the phase diagram of the kinetic glass transition is studied by time-convolutionless mode-coupling theory (TMCT). Using numerical calculations, TMCT is shown to recover all the remarkable features predicted by the mode-coupling theory for attractive colloids: the glass-liquid-glass reentrant, the glass-glass transition, and the higher-order singularities. It is also demonstrated through the comparisons with the results of molecular dynamics for the binary attractive colloids that TMCT improves the critical values of the volume fraction. In addition, a schematic model of three control parameters is investigated analytically. It is thus confirmed that TMCT can describe the glass-glass transition and higher-order singularities even in such a schematic model.

  7. Alteration in scaling behavior of short-term heartbeat time series for professional shooting athletes from rest to exercise

    NASA Astrophysics Data System (ADS)

    Zhuang, Jian Jun; Ning, Xin Bao; He, Ai Jun; Zou, Ming; Sun, Biao; Wu, Xu Hui

    2008-11-01

    Scaling analysis of heartbeat time series has emerged as a useful tool for assessing the autonomic cardiac control under various physiologic and pathologic conditions. We study the heartbeat activity and scaling behavior of heartbeat fluctuations regulated by autonomic nervous system for professional shooting athletes under two states: rest and exercise, by applying the detrended fluctuation analysis method. We focus on alteration in correlation properties of heartbeat intervals for the shooters from rest to exercise, which may have a potential value in monitoring the quality of training and evaluating the sports capacity of the athletes. The result shows that scaling exponents of short-term heart rate variability signals from the shooters get significantly larger during exercise compared with those obtained at rest. It demonstrates that during exercise stronger correlations appear in the heartbeat series of shooting athletes in order to satisfy the specific requirements for high concentration and better control on their heart beats.

  8. Positive Pacing Strategies Are Utilized by Elite Male and Female Para-cyclists in Short Time Trials in the Velodrome

    PubMed Central

    Wright, Rachel L.

    2016-01-01

    In para-cycling, competitors are classed based on functional impairment resulting in cyclists with neurological and locomotor impairments competing against each other. In Paralympic competition, classes are combined by using a factoring adjustment to race times to produce the overall medallists. Pacing in short-duration track cycling events is proposed to utilize an “all-out” strategy in able-bodied competition. However, pacing in para-cycling may vary depending on the level of impairment. Analysis of the pacing strategies employed by different classification groups may offer scope for optimal performance; therefore, this study investigated the pacing strategy adopted during the 1-km time trial (TT) and 500-m TT in elite C1 to C3 para-cyclists and able-bodied cyclists. Total times and intermediate split times (125-m intervals; measured to 0.001 s) were obtained from the C1-C3 men's 1-km TT (n = 28) and women's 500-m TT (n = 9) from the 2012 Paralympic Games and the men's 1-km TT (n = 19) and women's 500-m TT (n = 12) from the 2013 UCI World Track Championships from publically available video. Split times were expressed as actual time, factored time (for the para-cyclists) and as a percentage of total time. A two-way analysis of variance was used to investigate differences in split times between the different classifications and the able-bodied cyclists in the men's 1-km TT and between the para-cyclists and able-bodied cyclists in the women's 500-m TT. The importance of position at the first split was investigated with Kendall's Tau-b correlation. The first 125-m split time was the slowest for all cyclists, representing the acceleration phase from a standing start. C2 cyclists were slowest at this 125-m split, probably due to a combination of remaining seated in this acceleration phase and a high proportion of cyclists in this group being trans-femoral amputees. Not all cyclists used aero-bars, preferring to use drop, flat or bullhorn handlebars. Split times

  9. Seasonal comparisons of meteorological and agricultural drought indices in Morocco using open short time-series data

    NASA Astrophysics Data System (ADS)

    Ezzine, Hicham; Bouziane, Ahmed; Ouazar, Driss

    2014-02-01

    Although the preliminary investigations of NDWI demonstrated its sensitivity to vegetation water content, drought indices based on NDWI short time-series are still understudied compared to those derived from NDVI and LST, such as VCI, SVI and TCI. On the basis of the open data, this paper introduces a new index derived from NDWI short time-series, and explores its performance for drought monitoring in Mediterranean semi-arid area. The new index, Standardized Water Index (SWI), was calculated and spatiotemporally compared to both meteorological drought index (TRMM-based SPI) and to agricultural drought index (NDVI-based SVI) for the hydrological years and autumn, winter and spring seasons during a period of 15 years (1998-2012). Furthermore, the response and spatial agreement of the meteorological and agricultural drought indices (SWI, SVI and SPI) were compared over two land use classes, rainfed agriculture and vegetation cover, for the studied years and seasons. The validation of SWI was based on in situ SPI and cereal productions. The analysis of the 336 cross-tables, proportions of concordance and Cohen's kappa coefficients indicate that SWI and SVI are concordant comparing to other combinations for hydrological years and for the three seasons. The study points that the spatial agreements of drought indices over rainfed agriculture and over vegetation cover are different. It is relatively more important in the rainfed agriculture than in the vegetation cover areas. Our results show that the agreement between vegetation drought indices and meteorological drought indices is moderated to low and the SPI is slightly more concordant with SWI when it is compared to SVI in autumn and winter seasons. The validation approach indicates that drought affected area, according to SWI, is highly correlated with cereal production. Likewise, a satisfactory correlation was revealed between SWI and in situ SPI.

  10. Short-Term Chromospheric Variability in alpha Tauri (K5 III): Results from IUE Time Series Observations

    NASA Technical Reports Server (NTRS)

    Cuntz, Manfred; Deeney, Bryan D.; Brown, Alexander; Stencel, Robert E.

    1996-01-01

    We evaluate time series observations of chromospheric lines (Mg II, Mg I, and C II) for the K giant alpha Tau obtained using the IUE LWP camera at high dispersion. These observations cover a time span of about 2 weeks in 1994 February-March and were designed to resolve variations occurring within hours, days, and weeks. We consider the observational results in relation to theoretical acoustic heating models, motivated by the fact that alpha Tau may exhibit a basal (i.e., minimum) level of chromospheric activity. The data reveal flux variations between the extremes of 8% in Mg II h+k and 15% in each emission component. These variations occur on timescales as short as 8 hr but not on timescales longer than approx.3 days. For the h and k components, flux variations occurring on a timescale as short as 1.5 hr are also found. These changes are often not correlated (and are sometimes even anticorrelated), leading to remarkable differences in the h/k ratios. We argue that these results are consistent with the presence of strong acoustic shocks, which can lead to variable Mg II line emission when only a small number of strong shocks are propagating through the atmosphere. We deduce the electron density in the C II lambda 2325 line formation region to be log(base e) of N. approx. equals 9.0, in agreement with previous studies. Our data provide evidence that the Mg II basal flux limit for K giants might be a factor of 4 higher than suggested by Rutten et al.

  11. 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

  12. Short-pulsed laser transport in absorbing and scattering media: time-based versus frequency-based approaches

    NASA Astrophysics Data System (ADS)

    Francoeur, Mathieu; Rousse, Daniel R.

    2007-09-01

    Optical tomography (OT) is a promising non-intrusive characterization technique of absorbing and scattering media that uses transmitted and/or reflected signals of samples irradiated with visible or near-infrared light. The quality of OT techniques is directly related to the accuracy of their forward models due to the use of inversion algorithms. In this paper, forward models for transient OT approaches are investigated. The system under study involves a one-dimensional absorbing and scattering medium illuminated by a short laser pulse; this problem is solved using a discrete ordinates-finite volume (DO-FV) method in both time and frequency domain. Previous works have shown that time-domain approaches coupled with first order spatial interpolation schemes cannot represent the physics of the problem adequately as transmitted fluxes emerge before the minimal physical time required to leave the medium. In this work, the Van Leer and Superbee flux limiters, combined with the second order Lax-Wendroff scheme, are used in an attempt to prevent this. Results show that despite significant improvement, flux limiters fail to completely eliminate the physically unrealistic behaviour. On the other hand, results for transmittance obtained from the frequency-based method are accurate, without physically unrealistic behaviours at early time periods. The frequency-dependent approach is however computationally expensive, since it requires approximately five times more computational time than its temporal counterpart when used as a forward model for transient OT. On the other hand, the great advantages of the frequency-based approach is that limited windows of temporal signals can be calculated efficiently (in transient OT), and it can also be used as a forward model for steady-state, frequency-based and transient OT techniques.

  13. 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, 100–350 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 30–80 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

  14. Short-time dynamics of 2-thiouracil in the light absorbing S2(ππ(∗)) state.

    PubMed

    Jiang, Jie; Zhang, Teng-shuo; Xue, Jia-dan; Zheng, Xuming; Cui, Ganglong; Fang, Wei-hai

    2015-11-07

    Ultrahigh quantum yields of intersystem crossing to the lowest triplet state T1 are observed for 2-thiouracils (2TU), which is in contrast to the natural uracils that predominantly exhibit ultrafast internal conversion to the ground state upon excitation to the singlet excited state. The intersystem crossing mechanism of 2TU has recently been investigated using second-order perturbation methods with a high-level complete-active space self-consistent field. Three competitive nonadiabatic pathways to the lowest triplet state T1 from the initially populated singlet excited state S2 were proposed. We investigate the initial decay dynamics of 2TU from the light absorbing excited states using resonance Raman spectroscopy, time-dependent wave-packet theory in the simple model, and complete-active space self-consistent field (CASSCF) and time dependent-Becke's three-parameter exchange and correlation functional with the Lee-Yang-Parr correlation functional (TD-B3LYP) calculations. The obtained short-time structural dynamics in easy-to-visualize internal coordinates were compared with the CASSCF(16,11) predicted key nonadiabatic decay routes. Our results indicate that the predominant decay pathway initiated at the Franck-Condon region is toward the S2/S1 conical intersection point and S2T3 intersystem crossing point, but not toward the S2T2 intersystem crossing point.

  15. Thermal inactivation of Pediococcus sp. in simulated apple cider during high-temperature short-time pasteurization.

    PubMed

    Piyasena, P; McKellar, R C; Bartlett, F M

    2003-01-26

    Prompted by concerns regarding outbreaks of food-borne illness which have occurred due to the consumption of commercial, nonpasteurized fruit juices contaminated with Escherichia coli O157:H7, the US Food and Drug Administration and Canadian Food Inspection Agency are considering several new safety standards to apply to fresh juices, including mandatory pasteurization of all apple cider. In support of these initiatives, a study was conducted to evaluate the pasteurization of simulated cider using a heat-resistant nonpathogenic test bacterium, Pediococcus sp. NRRL B-2354. Thermal inactivation of the Pediococcus sp. was determined using a pilot scale high-temperature short-time (HTST) pasteurizer with a plate heat exchanger. The cumulative lethal effect, or pasteurization effect (PE), was obtained by converting times at different temperatures in the various sections of the pasteurizer to the equivalent time at the reference temperature (72 degrees C). PE was then related by a simple linear function to the log(10) of the percentage of viable counts with a power transformation of the PE values to improve linear fit. r(2) values for the four Pediococcus sp. trials varied from 0.921 to 0.981. Intertrial variation was incorporated into the model using @RISK simulation software. Output from simulations confirmed that treatment at 71 degrees C for 16 s can ensure a 5-log reduction of Pediococcus sp.

  16. Short-time dynamics of 2-thiouracil in the light absorbing S2(ππ∗) state

    NASA Astrophysics Data System (ADS)

    Jiang, Jie; Zhang, Teng-shuo; Xue, Jia-dan; Zheng, Xuming; Cui, Ganglong; Fang, Wei-hai

    2015-11-01

    Ultrahigh quantum yields of intersystem crossing to the lowest triplet state T1 are observed for 2-thiouracils (2TU), which is in contrast to the natural uracils that predominantly exhibit ultrafast internal conversion to the ground state upon excitation to the singlet excited state. The intersystem crossing mechanism of 2TU has recently been investigated using second-order perturbation methods with a high-level complete-active space self-consistent field. Three competitive nonadiabatic pathways to the lowest triplet state T1 from the initially populated singlet excited state S2 were proposed. We investigate the initial decay dynamics of 2TU from the light absorbing excited states using resonance Raman spectroscopy, time-dependent wave-packet theory in the simple model, and complete-active space self-consistent field (CASSCF) and time dependent-Becke's three-parameter exchange and correlation functional with the Lee-Yang-Parr correlation functional (TD-B3LYP) calculations. The obtained short-time structural dynamics in easy-to-visualize internal coordinates were compared with the CASSCF(16,11) predicted key nonadiabatic decay routes. Our results indicate that the predominant decay pathway initiated at the Franck-Condon region is toward the S2/S1 conical intersection point and S2T3 intersystem crossing point, but not toward the S2T2 intersystem crossing point.

  17. Transport of marked pebbles in short periods of time on a coarse clastic beach (Marina di Pisa, Italy)

    NASA Astrophysics Data System (ADS)

    Bertoni, D.; Ciavola, P.; Grottoli, E.; Sarti, G.

    2012-04-01

    Transport of coarse sediments on coarse clastic beaches still presents aspects that are not fully understood. For instance, there is a generally perceived notion that during fair-weather periods coarse grains hardly move, if not at all. The aim of this experiment is to prove that sediments such as pebbles are subject to significant shift in very short lapses of time and under low energy waves. An artificial coarse clastic beach at Marina di Pisa (Tuscany, Italy) was chosen as study site: Barbarossa beach is 110 m long and is bounded by two groynes. The mean grain size is about 40-to-50 mm. About 80 pebbles were marked by means of the RFID technology, which enables to univocally identify the tracers. The marked pebbles were released along cross-shore transects (one pebble each on the fair-weather berm, on the beachface and on the step crest) on the morning of September 15th, and two recovery campaigns were carried out after 6 and 24 hours from the injection. No particular wave activity was recorded during the time frame of the experiment. After the first recovery campaign, which was performed 6 hours later than the injection, about 94% of the pebbles were detected. After the second recovery campaign, 24 hours later, the recovery rate decreased to 89%. Considering that the technique provides for detection of tracers within 50 cm, the resulting loss of pebbles after so brief spans of time is remarkable. The lack of detection of few tracers implies that the transport rate that they experienced is not negligible. The highest rate of losses was recorded on the beachface, the zone that is subjected the most to waves even under calm conditions. Pebble movement is also confirmed by the fact that tracers detected after the first recovery campaign were not detected once again after the second recovery campaign, and vice versa. The results of the experiment are useful to better define the transport of coarse sediments, verifying that pebbles have to be expected be moving even

  18. Classification mapping and species identification of salt marshes based on a short-time interval NDVI time-series from HJ-1 optical imagery

    NASA Astrophysics Data System (ADS)

    Sun, Chao; Liu, Yongxue; Zhao, Saishuai; Zhou, Minxi; Yang, Yuhao; Li, Feixue

    2016-03-01

    Salt marshes are seen as the most dynamic and valuable ecosystems in coastal zones, and in these areas, it is crucial to obtain accurate remote sensing information on the spatial distributions of species over time. However, discriminating various types of salt marsh is rather difficult because of their strong spectral similarities. Previous salt marsh mapping studies have focused mainly on high spatial and spectral (i.e., hyperspectral) resolution images combined with auxiliary information; however, the results are often limited to small regions. With a high temporal and moderate spatial resolution, the Chinese HuanJing-1 (HJ-1) satellite optical imagery can be used not only to monitor phenological changes of salt marsh vegetation over short-time intervals, but also to obtain coverage of large areas. Here, we apply HJ-1 satellite imagery to the middle coast of Jiangsu in east China to monitor changes in saltmarsh vegetation cover. First, we constructed a monthly NDVI time-series to classify various types of salt marsh and then we tested the possibility of using compressed time-series continuously, to broaden the applicability of this particular approach. Our principal findings are as follows: (1) the overall accuracy of salt marsh mapping based on the monthly NDVI time-series was 90.3%, which was ∼16.0% higher than the single-phase classification strategy; (2) a compressed time-series, including NDVI from six key months (April, June-September, and November), demonstrated very little reduction (2.3%) in overall accuracy but led to obvious improvements in unstable regions; and (3) a simple rule for Spartina alterniflora identification was established using a scene solely from November, which may provide an effective way for regularly monitoring its distribution.

  19. Functional traits as indicators of fodder provision over a short time scale in species-rich grasslands

    PubMed Central

    Ansquer, Pauline; Duru, Michel; Theau, Jean Pierre; Cruz, Pablo

    2009-01-01

    Background and Aims Fodder provision in species-rich grasslands, i.e. herbage growth, proportion of leaf, and leaf and stem digestibility, is difficult to predict for short periods of time, such as between two defoliations or less. The value of two methods based on plant traits for evaluating these agronomic properties was examined. Methods One method is based on plant trait measurements on the plant community (leaf dry matter content, plant height, flowering date); the other is on vegetation composition expressed as plant functional types (acquisitive versus conservative PFTs) established by measuring leaf dry matter content on pure grass stands. The experiment consisted of 18 fields with three different defoliation regimes (combinations of cutting and grazing) and two levels of fertilization. To establish a growth curve over the first growth cycle, herbage was sampled about 10 times in spring. Key Results Coefficients of correlation between agronomic properties of the vegetation and its functional composition were higher when the latter was assessed through PFT and an indicator of the plant nutrient status (Ni) instead of measured plant traits. The date at which the ceiling yield occurred for the standing herbage mass or only the leaf component, which varied by up to 500 degree-days between treatments, and the leaf proportion, depended entirely on the PFT, and largely so for the leaf digestibility. The standing herbage mass at the time of ceiling yield depended only on Ni, or mainly so in the case of the daily herbage growth rate. Similar plant digestibility between plant communities was found at flowering time, although there were big differences in PFT composition. The shape of the growth curve was flatter when there was great functional diversity in the plant community. Conclusions The PFT composition and the Ni were more reliable than the plant functional traits measured in the field for evaluating herbage growth pattern and digestibility in spring. PMID

  20. 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 νDDS) from the velocity profile. DDS exploits the simple fact that the optically up-converted data ride on top of a base velocity (ν0, the apparent velocity at no motion) with a rapid rise to a high velocity (νf) of a few km/s or more. Consequently, the frequency content of the signal must describe a velocity profile that increases from ν0 to ν0 + νf. The DDS technique produces velocity reversals in the processed data before shock breakout when ν0 < νDDS < ν0 + νf. 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.

  1. Real-time short-wave infrared hyperspectral conformal imaging sensor for the detection of threat materials

    NASA Astrophysics Data System (ADS)

    Nelson, Matthew P.; Shi, Lei; Zbur, Lucas; Priore, Ryan J.; Treado, Patrick J.

    2016-05-01

    Hyperspectral imaging (HSI) systems can provide sensitive and specific detection and identification of high value targets in the presence of complex backgrounds. However, current generation sensors are typically large and costly to field, and do not usually operate in real-time. Sensors that are capable of real-time operation have to compromise on the number of spectral bands, image definition, and/or the number of targets being detected. Additionally, these systems command a high cost and are typically designed and configured for specific mission profiles, making them unable to adapt to multiple threats within often rapidly evolving and dynamic missions. Despite these shortcomings, HSI-based sensors have proven to be valuable tools, thus resulting in increased demand for HSI technology. A cost-effective sensor system that can easily and quickly adapt to accomplish significantly different tasks in a changing environment is highly desirable. The capability to detect and identify user-defined targets in complex backgrounds under a range of varying conditions with an easily reconfigured, automated, real-time, portable HSI sensor is a critical need. ChemImage Sensor Systems (CISSTM) is developing a novel real-time, adaptable, compressive sensing short-wave infrared (SWIR) hyperspectral imaging technology called the Reconfigurable Conformal Imaging Sensor (RCIS). RCIS will address many shortcomings of current generation systems and offer improvements in operational agility and detection performance, while addressing sensor weight, form factor and cost needs. This paper discusses the development of the RCIS system, and considers its application in various use scenarios.

  2. 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.; 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.

  3. Body mass index change in females after short-time life style intervention is not dependent on the FTO polymorphisms.

    PubMed

    Dlouhá, D; Suchánek, P; Lánská, V; Hubáček, J A

    2011-01-01

    Variants within the FTO gene are important determinants of body mass index (BMI), but their role in determination of BMI changes after combined dietary/physical activity intervention is unclear. We have analyzed 107 unrelated overweight non-diabetic Czech females (BMI over 27.5 kg/m(2), age 49.2+/-12.3 years). FTO variants rs17817449 (first intron) and rs17818902 (third intron) were genotyped. The life style modification program (10 weeks) consisted of an age-matched reduction of energy intake and exercise program (aerobic exercise 4 times a week, 60 min each). The mean BMI before intervention was 32.8+/-4.2 kg/m(2) and the mean achieved weight loss was 4.8+/-3.5 kg (5.3+/-3.5 %, max. -15.5 kg, min. +2.0 kg, p<0.01). No significant association between BMI decrease and FTO variants was found. Also waist-to-hip ratio, body composition (body fat, water, active tissue), lipid parameters (total, LDL and HDL cholesterol, triglycerides) glucose and hsCRP changes were independent on FTO variants. FTO variants rs17817449 and rs17818902 are not associated with BMI changes after combined short time dietary/physical activity intervention in overweight females.

  4. Time-dependent density functional theory of high-intensity short-pulse laser irradiation on insulators

    NASA Astrophysics Data System (ADS)

    Sato, S. A.; Yabana, K.; Shinohara, Y.; Otobe, T.; Lee, K.-M.; Bertsch, G. F.

    2015-11-01

    We calculate the energy deposition by very short laser pulses in SiO2 (α -quartz) with a view to establishing systematics for predicting damage and nanoparticle production. The theoretical framework is time-dependent density functional theory, implemented by the real-time method in a multiscale representation. For the most realistic simulations we employ a meta-GGA Kohn-Sham potential similar to that of Becke and Johnson. We find that the deposited energy in the medium can be accurately modeled as a function of the local electromagnetic pulse fluence. The energy-deposition function can in turn be quite well fitted to the strong-field Keldysh formula for a range of intensities from below the melting threshold to well beyond the ablation threshold. We find reasonable agreement between the damage threshold and the energy required to melt the substrate. Also, the depth of the ablated crater at higher energies is fairly well reproduced assuming that the material ablated with the energy exceeds that required to convert it to an atomic fluid. However, the calculated ablation threshold is higher than experiment, suggesting a nonthermal mechanism for the surface ablation.

  5. Long and short time variability of the global and the hemisphere temperature anomalies -Application of the Cochrane-Orcutt method

    NASA Astrophysics Data System (ADS)

    Werner, Rolf; Valev, Dimitare; Danov, Dimitar; Goranova, M.

    Climate change holds a key position in science and policy today. A central issue to discuss in the scientific publications is the question how much humans contribute to the climate warming. To get answers in the last decades a lot of efforts were made to model the processes determining the climate, to make forecasts under defined conditions for the development of the society (climate projections). Another scientific tendency to find a more probable right answer consists in the application and development of the statistics to study responses of different climate forcings. Here a classical statistical method -the linear regression -is applied to examine the parts of the global and hemisphere warming due to different radiation forcings, by the use of their long and short time variabilities. The residuals of the regressions are significantly auto-correlated. Therefore the Cochrane-Orcutt method is applied to test the statistical significances. By multiple regression it is found that the main part of the temperature variability is caused by CO2. The impact of the total solar irradiance during the examined time period of 1866 up to 2000 is at the critical level of significance.

  6. 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 25°C/21°C, ‘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 35°C 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

  7. Nucleoside uptake in macrophages from various murine strains: a short-time and a two-step stimulation model

    SciTech Connect

    Busolo, F.; Conventi, L.; Grigolon, M.; Palu, G. )

    1991-06-28

    Kinetics of (3H)-uridine uptake by murine peritoneal macrophages (pM phi) is early altered after exposure to a variety of stimuli. Alterations caused by Candida albicans, lipopolysaccharide (LPS) and recombinant interferon-gamma (rIFN-gamma) were similar in SAVO, C57BL/6, C3H/HeN and C3H/HeJ mice, and were not correlated with an activation process as shown by the amount of tumor necrosis factor-alpha (TNF-alpha) being released. Short-time exposure to all stimuli resulted in an increased nucleoside uptake by SAVO pM phi, suggesting that the tumoricidal function of this cell either depends from the type of stimulus or the time when the specific interaction with the cell receptor is taking place. Experiments with priming and triggering signals confirmed the above findings, indicating that the increase or the decrease of nucleoside uptake into the cell depends essentially on the chemical nature of the priming stimulus. The triggering stimulus, on the other hand, is only able to amplify the primary response.

  8. Shorting time of magnetically insulated reflex-ion diodes from the neutral-atom charge-exchange mechanism

    SciTech Connect

    Strobel, G.

    1981-10-01

    In a magnetically insulated diode, collision-free electrons return to the cathode and no electron current is present at the anode. Electron transport to the anode is studied in this paper. Steady-state space-charge-limited flow is assumed initially. Breakdown of ion flow occurs when static neutral atoms at the anode undergo charge exchange, which results in neutral atoms drifting across the diode. These are subsequently ionized by reflexing ions producing electrons trapped in Larmor orbits throughout the diode. These electrons drift to the anode via ionization and inelastic collisions with other neutral atoms. Model calculations compare the effects of foil and mesh cathodes. Steady-state space-charge-limited ion current densities are calculated. The neutral atom density at the cathode is determined as a function of time. The shorting time of the diode is scaled versus the electrode separation d, the diode potential V/sub 0/, the magnetic field, and the initial concentration of static neutron atoms.

  9. Revisiting Constructivist Teaching Methods in Ontario Colleges Preparing for Accreditation

    ERIC Educational Resources Information Center

    Schultz, Rachel A.

    2015-01-01

    At the time of writing, the first community colleges in Ontario were preparing for transition to an accreditation model from an audit system. This paper revisits constructivist literature, arguing that a more pragmatic definition of constructivism effectively blends positivist and interactionist philosophies to achieve both student centred…

  10. Topside Sounding As A Powerful Tool For Global Detection of Short-time Precursors of Destructive Earthquakes

    NASA Astrophysics Data System (ADS)

    Pulinets, S.

    The recent years brought a lot of publications on the registration onboard satellites some variations of ionosphere parameters associated with the seismic activity within few days/hours before the strong earthquakes over seismically active areas. The num- ber of information exceeded the threshold when some countries started to build spe- cialized satellites to register ionospheric earthquake precursors from space (Russia, France, Italy, Ukraine, Japan). Among the different kinds of measurements the most promising are results of vertical sounding from onboard the satellite with the help of topside sounder. The advantage of the technique is that the satellite gives information not on the only one parameter (such as electron temperature or local concentration) but the comprehensive picture of the three dimensional state of the ionosphere due to combination of remote sensing and in-situ abilities of the device. The sounding gives the vertical cross-section of the ionosphere (electron concentration vertical pro- files along the satellite orbit), the state of the plasma inhomogeneity (spread of the ionogram), estimation of electron temperature and the ion mass (scale height of the profile), tides and waves (variation of heights of different levels of electron concen- tration), particle fluxes (HF emission registered by the sounder receiver), tempera- ture anisotropy (plasma instability emissions registered by the sounder receiver), local magnetic field value (plasma resonances including electron gyrofrequency harmon- ics), etc. The multiple examples of registration of ionospheric precursors with the help of topside sounder will be demonstrated. Statistical analysis of the ionospheric sound- ing shows that the topside sounder gives the most reliable and confident measurements of the short-time ionospheric precursors in comparison with any other technique. Nevertheless, the sounder itself creates some problems for the satellite payload due to interferences connected with

  11. Interactions of Grazing History, Cattle Removal and Time since Rain Drive Divergent Short-Term Responses by Desert Biota

    PubMed Central

    Frank, Anke S. K.; Dickman, Chris R.; Wardle, Glenda M.; Greenville, Aaron C.

    2013-01-01

    Arid grasslands are used worldwide for grazing by domestic livestock, generating debate about how this pastoral enterprise may influence native desert biota. One approach to resolving this question is to experimentally reduce livestock numbers and measure the effects. However, a key challenge in doing this is that historical grazing impacts are likely to be cumulative and may therefore confound comparisons of the short-term responses of desert biota to changes in stocking levels. Arid areas are also subject to infrequent flooding rainfalls that drive productivity and dramatically alter abundances of flora and fauna. We took advantage of an opportunity to study the recent effects of a property-scale cattle removal on two properties with similarly varied grazing histories in central Australia. Following the removal of cattle in 2006 and before and after a significant rainfall event at the beginning of 2007, we sampled vegetation and small vertebrates on eight occasions until October 2008. Our results revealed significant interactions of time of survey with both grazing history and grazing removal for vascular plants, small mammals and reptiles. The mammals exhibited a three-way interaction of time, grazing history and grazing removal, thus highlighting the importance of careful sampling designs and timing for future monitoring. The strongest response to the cessation of grazing after two years was depressed reproductive output of plants in areas where cattle continued to graze. Our results confirm that neither vegetation nor small vertebrates necessarily respond immediately to the removal of livestock, but that rainfall events and cumulative grazing history are key determinants of floral and faunal performance in grassland landscapes with low and variable rainfall. We suggest that improved assessments could be made of the health of arid grazing environments if long-term monitoring were implemented to track the complex interactions that influence how native biota

  12. Short message service (SMS) reminders and real-time adherence monitoring improve antiretroviral therapy adherence in rural Uganda

    PubMed Central

    Haberer, Jessica E.; Musiimenta, Angella; Atukunda, Esther C.; Musinguzi, Nicholas; Wyatt, Monique A.; Ware, Norma C.; Bangsberg, David R.

    2016-01-01

    Objective: To explore the effects of four types of short message service (SMS) plus real-time adherence monitoring on antiretroviral therapy (ART) adherence: daily reminders, weekly reminders, reminders triggered after a late or missed dose (delivered to patients), and notifications triggered by sustained adherence lapses (delivered to patient-nominated social supporters). Design: Pilot randomized controlled trial. Methods: Sixty-three individuals initiating ART received a real-time adherence monitor and were randomized (1 : 1 : 1): (1) Scheduled SMS reminders (daily for 1 month, weekly for 2 months), then SMS reminders triggered by a late or missed dose (no monitoring signal within 2 h of expected dosing); SMS notifications to social supporters for sustained adherence lapses (no monitoring signal for >48 h) added after 3 months. (2) Triggered SMS reminders starting at enrolment; SMS notifications to social supporters added after 3 months. (3) Control: No SMS. HIV RNA was determined at 9 months. Percentage adherence and adherence lapses were compared by linear generalized estimating equations and Poisson regression, respectively. Results: Median age was 31 years, 65% were women, and median enrolment CD4+ cell count was 322 cells/μl 97% took once daily tenofovir/emtricitabine/efavirenz. Compared to control, adherence was 11.1% higher (P = 0.04) and more than 48-h lapses were less frequent (IRR 0.6, P = 0.02) in the scheduled SMS arm. Adherence and more than 48-h lapses were similar in the triggered SMS arm and control. No differences in HIV RNA were seen. Conclusion: Scheduled SMS reminders improved ART in the context of real-time monitoring. Larger studies are needed to determine the impact of triggered reminders and role of social supporters in improving adherence. PMID:26760452

  13. 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.

  14. Interactions of grazing history, cattle removal and time since rain drive divergent short-term responses by desert biota.

    PubMed

    Frank, Anke S K; Dickman, Chris R; Wardle, Glenda M; Greenville, Aaron C

    2013-01-01

    Arid grasslands are used worldwide for grazing by domestic livestock, generating debate about how this pastoral enterprise may influence native desert biota. One approach to resolving this question is to experimentally reduce livestock numbers and measure the effects. However, a key challenge in doing this is that historical grazing impacts are likely to be cumulative and may therefore confound comparisons of the short-term responses of desert biota to changes in stocking levels. Arid areas are also subject to infrequent flooding rainfalls that drive productivity and dramatically alter abundances of flora and fauna. We took advantage of an opportunity to study the recent effects of a property-scale cattle removal on two properties with similarly varied grazing histories in central Australia. Following the removal of cattle in 2006 and before and after a significant rainfall event at the beginning of 2007, we sampled vegetation and small vertebrates on eight occasions until October 2008. Our results revealed significant interactions of time of survey with both grazing history and grazing removal for vascular plants, small mammals and reptiles. The mammals exhibited a three-way interaction of time, grazing history and grazing removal, thus highlighting the importance of careful sampling designs and timing for future monitoring. The strongest response to the cessation of grazing after two years was depressed reproductive output of plants in areas where cattle continued to graze. Our results confirm that neither vegetation nor small vertebrates necessarily respond immediately to the removal of livestock, but that rainfall events and cumulative grazing history are key determinants of floral and faunal performance in grassland landscapes with low and variable rainfall. We suggest that improved assessments could be made of the health of arid grazing environments if long-term monitoring were implemented to track the complex interactions that influence how native biota

  15. Short term effects of air pollution on health: a European approach using epidemiologic time series data: the APHEA protocol.

    PubMed Central

    Katsouyanni, K; Schwartz, J; Spix, C; Touloumi, G; Zmirou, D; Zanobetti, A; Wojtyniak, B; Vonk, J M; Tobias, A; Pönkä, A; Medina, S; Bachárová, L; Anderson, H R

    1996-01-01

    BACKGROUND AND OBJECTIVES: Results from several studies over the past five years have shown that the current levels of pollutants in Europe and North America have adverse short term effects on health. The APHEA project aims to quantifying these in Europe, using standardised methodology. The project protocol and analytical methodology are presented here. DESIGN: Daily time series data were gathered for several air pollutants (sulphur dioxide; particulate matter, measured as total particles or as the particle fraction with an aerodynamic diameter smaller than a certain cut off, or as black smoke; nitrogen dioxide; and ozone) and health outcomes (the total and cause specific number of deaths and emergency hospital admissions). The data included fulfilled the quality criteria set by the APHEA protocol. SETTING: Fifteen European cities from 10 different countries with a total population over 25 million. METHODOLOGY: The APHEA collaborative group decided on a specific methodological procedure to control for confounding effects and evaluate the hypothesis. At the same time there was sufficient flexibility to allow local characteristics to be taken into account. The procedure included modelling of all potential confounding factors (that is, seasonal and long term patterns, meteorological factors, day of the week, holidays, and other unusual events), choosing the "best" air pollution models, and applying diagnostic tools to check the adequacy of the models. The final analysis used autoregressive Poisson models allowing for overdispersion. Effects were reported as relative risks contrasting defined increases in the corresponding pollutant levels. Each participating group applied the analyses to their own data. CONCLUSIONS: This methodology enabled results from many different European settings to be considered collectively. It represented the best available compromise between feasibility, comparability, and local adaptibility when using aggregated time series data not

  16. Hershfield factor revisited: Correcting annual maximum precipitation

    NASA Astrophysics Data System (ADS)

    Papalexiou, Simon Michael; Dialynas, Yannis G.; Grimaldi, Salvatore

    2016-11-01

    The Hershfield factor (H) is a multiplier aiming to correct the error between fixed time interval maxima (F-maxima) and sliding maxima (S-maxima) as a direct consequence of temporal discretization of hydrometeorological time series. Rainfall is typically recorded over discrete intervals, e.g., over fixed 24-h intervals, and the historical series express average values over these intervals. This temporal discretization introduces an important systematic error on rainfall characteristics such as the annual maxima. Research to date suggests that our understanding of this error across different time scales is limited. In this study we revisit the probabilistic nature of the H-factor in an unprecedentedly large analysis comprising thousands of up-to-date hourly records across the US. We study the probabilistic behavior of F- and S-maxima of the historical records. We quantify the discretization error of the rainfall maxima and its statistical properties at different time scales. We revisit the classical definitions of the H-factor and we investigate the exact probability distribution of H-factor. We introduce a bounded exponential distribution with an atom at one, which closely depicts the empirical distribution of the H-factor. Notable is the result that the proposed mixed-type distribution is invariant across a range of time scales. This work clarifies the probabilistic nature of the rainfall maxima correction. The results may have wide use across a range of hydrological applications.

  17. Demonstration of a time-integrated short line of sight neutron imaging system for inertial confinement fusion

    SciTech Connect

    Simpson, R. Danly, C.; Fatherley, V. E.; Merrill, F. E.; Volegov, P.; Wilde, C.; Christensen, K.; Fittinghoff, D.; Grim, G. P.; Izumi, N.; Jedlovec, D.; Skulina, K.

    2015-12-15

    The Neutron Imaging System (NIS) is an important diagnostic for understanding implosions of deuterium-tritium capsules at the National Ignition Facility. While the detectors for the existing system must be positioned 28 m from the source to produce sufficient imaging magnification and resolution, recent testing of a new short line of sight neutron imaging system has shown sufficient resolution to allow reconstruction of the source image with quality similar to that of the existing NIS on a 11.6 m line of sight. The new system used the existing pinhole aperture array and a stack of detectors composed of 2 mm thick high-density polyethylene converter material followed by an image plate. In these detectors, neutrons enter the converter material and interact with protons, which recoil and deposit energy within the thin active layer of the image plate through ionization losses. The described system produces time-integrated images for all neutron energies passing through the pinhole. We present details of the measurement scheme for this novel technique to produce energy-integrated neutron images as well as source reconstruction results from recent experiments at NIF.

  18. On board short-time high temperature heat treatment of ballast water: a field trial under operational conditions.

    PubMed

    Quilez-Badia, Gemma; McCollin, Tracy; Josefsen, Kjell D; Vourdachas, Anthony; Gill, Margaret E; Mesbahi, Ehsan; Frid, Chris L J

    2008-01-01

    A ballast water short-time high temperature heat treatment technique was applied on board a car-carrier during a voyage from Egypt to Belgium. Ballast water from three tanks was subjected for a few seconds to temperatures ranging from 55 degrees C to 80 degrees C. The water was heated using the vessel's heat exchanger steam and a second heat exchanger was used to pre-heat and cool down the water. The treatment was effective at causing mortality of bacteria, phytoplankton and zooplankton. The International Maritime Organization (IMO) standard was not agreed before this study was carried out, but comparing our results gives a broad indication that the IMO standard would have been met in some of the tests for the zooplankton, in all the tests for the phytoplankton; and probably on most occasions for the bacteria. Passing the water through the pump increased the kill rate but increasing the temperature above 55 degrees C did not improve the heat treatment's efficacy.

  19. 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.

  20. Demonstration of a time-integrated short line of sight neutron imaging system for inertial confinement fusion.

    PubMed

    Simpson, R; Christensen, K; Danly, C; Fatherley, V E; Fittinghoff, D; Grim, G P; Izumi, N; Jedlovec, D; Merrill, F E; Skulina, K; Volegov, P; Wilde, C

    2015-12-01

    The Neutron Imaging System (NIS) is an important diagnostic for understanding implosions of deuterium-tritium capsules at the National Ignition Facility. While the detectors for the existing system must be positioned 28 m from the source to produce sufficient imaging magnification and resolution, recent testing of a new short line of sight neutron imaging system has shown sufficient resolution to allow reconstruction of the source image with quality similar to that of the existing NIS on a 11.6 m line of sight. The new system used the existing pinhole aperture array and a stack of detectors composed of 2 mm thick high-density polyethylene converter material followed by an image plate. In these detectors, neutrons enter the converter material and interact with protons, which recoil and deposit energy within the thin active layer of the image plate through ionization losses. The described system produces time-integrated images for all neutron energies passing through the pinhole. We present details of the measurement scheme for this novel technique to produce energy-integrated neutron images as well as source reconstruction results from recent experiments at NIF.

  1. 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 Mβ, where β ˜ -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 β 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 Gierliński 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.

  2. Dermal microvasculature and tissue selective thinning techniques (ultrasound and water-jet) of short-time expanded skin in dogs.

    PubMed

    Siegert, R; Danter, J; Jurk, V; Eggers, R; Krüger, S

    1998-01-01

    Certain reconstructive procedures, like auricular reconstructions, require thin and well-vascularized skin. The aims of this study were to analyze if the increased survival of expanded skin flaps was due to morphologic changes of the dermis, if thinning of short-time expanded skin was possible without harm to the microcirculation and if tissue selective cutting methods could be used to resect subcutaneous fat without damaging its vessels. Eighty-two 200-ml expanders were implanted into the trunk regions of 26 beagles and filled immediately with sterile saline. In the first series of experiments, the expansion was terminated after intervals of 0.5-5 weeks and dermal vessels were analyzed morphometrically. In the second series the expanded flaps were raised after 2 weeks and thinned solely surgically or with the additional use of an ultrasonic knife or with cutting by water jet. In contrast to sham flaps, the expanded skin showed only very few areas of necrosis and these were located superficially in most cases. The relative volume of the dermal vessels and their quantity showed a significant increase after the expansion. Additionally, the subcutaneous tissue could be thinned down to 0.4 mm with the water-jet-cutter. Findings demonstrated that the method used could create a well-vascularized skin flap of minimal thickness that could be very helpful for special reconstructive procedures.

  3. The Time-Dependent Schrödinger Equation Revisited: Quantum Optical and Classical Maxwell Routes to Schrödinger’s Wave Equation

    NASA Astrophysics Data System (ADS)

    Scully, Marlan O.

    In a previous paper [1-3] we presented quantum field theoretical and classical (Hamilton-Jacobi) routes to the time-dependent Schrödinger's equation (TDSE) in which the time t and position r are regarded as parameters, not operators. From this perspective, the time in quantum mechanics is argued as being the same as the time in Newtonian mechanics. We here provide a parallel argument, based on the photon wave function, showing that the time in quantum mechanics is the same as the time in Maxwell equations.

  4. Time-lapse ERT and DTS for seasonal and short-term monitoring of an alpine river hyporheic zone

    NASA Astrophysics Data System (ADS)

    Boaga, Jacopo; Laura, Busato; Mariateresa, Perri; Giorgio, Cassiani

    2016-04-01

    The hyporheic zone (HZ) is the area located beneath and adjacent to rivers and streams, where the interactions between surface water and groundwater take place. This complex physical domain allows the transport of several substances from a stream to the unconfined aquifer below, and vice versa, thus playing a fundamental role in the river ecosystem. The importance of the hyporheic zone makes its characterization a goal shared by several disciplines, which range from applied geophysics to biogeochemistry, from hydraulics to ecology. The frontier field of HZ characterization stays in applied non-invasive methodologies as Electrical Resistivity Tomography - ERT - and Distributed Temperature Sensing - DTS. ERT is commonly applied in cross-well configuration or with a superficial electrodes deployment while DTS is used in hydro-geophysics in the last decade, revealing a wide applicability to the typical issues of this field of study. DTS for hydro-geophysics studies is based on Raman scattering and employs heat as tracer and uses a fiber-optic cable to acquire temperature values. We applied both techniques for an alpine river case studies located in Val di Sole, TN, Italy. The collected measurements allow high-resolution characterization of the hyporheic zone, overcoming the critical problem of invasive measurements under riverbeds. In this work, we present the preliminary results regarding the characterization of the hyporheic zone of the alpine river obtained combining ERT and DTS time-lapse measurements. The data collection benefits from an innovative instrumentation deployment, which consists of both an ERT multicore cable and a DTS fiber-optic located in two separated boreholes drilled 5m under the watercourse and perpendicular to it. In particular we present the first year monitoring results and a short time-lapse monitoring experiment conducted during summer 2015. The site and the results here described are part of the EU FP7 CLIMB (Climate Induced Changes on the

  5. Application of attitude jitter detection based on short-time asynchronous images and compensation methods for Chinese mapping satellite-1.

    PubMed

    Sun, Tao; Long, Hui; Liu, Bao-Cheng; Li, Ying

    2015-01-26

    Given the recent development in high-resolution (HR) optical satellites, the study of both attitude jitter (AJ) detection and compensation has become increasingly essential to improving the radiometric and geometric quality of HR images. A group of HR optical stereo mapping satellites in China, mapping satellite-1 (MS-1) has launched two satellites and will launch one satellite to build a satellite network. The geometric accuracy of the launched MS-1 satellites is greater than 80 m because of the AJ caused by the instability of the platform. AJ detection and compensation are critical issues that must be addressed to improve the accuracy of geo-positioning and mapping before launching a new satellite. The present study employs a method of jitter detection based on short-time asynchronous images to detect MS-1 jitter. The adjacent overlapping areas of an original panchromatic image are used as detection images instead of the traditional multispectral images, and a differential recursion optimal estimation filter is proposed for the optimal estimation and elimination of the gross errors of the registration data procedure, thereby increasing the detection accuracy. The space variant blurring model and viewing angles correction method are employed for the radiometric and geometric jitter compensation of images, respectively. The methods of radiometric objective evaluation indices and geometric checkpoint are then utilised to evaluate the quality of jitter compensation. Finally, the DeZhou regional image (ShanDong province, China) from MS-1 is used as the experimental data. Results for the AJ of MS-1 are analysed and reported for the first time. The assessment results obtained show that both radiometric and geometric qualities greatly increase after the jitter compensation procedure. Thus, the work of this study for jitter detection and compensation effectively addresses the jitter of MS-1 HR optical satellites.

  6. Processing short-term and long-term information with a combination of polynomial approximation techniques and time-delay neural networks.

    PubMed

    Fuchs, Erich; Gruber, Christian; Reitmaier, Tobias; Sick, Bernhard

    2009-09-01

    Neural networks are often used to process temporal information, i.e., any kind of information related to time series. In many cases, time series contain short-term and long-term trends or behavior. This paper presents a new approach to capture temporal information with various reference periods simultaneously. A least squares approximation of the time series with orthogonal polynomials will be used to describe short-term trends contained in a signal (average, increase, curvature, etc.). Long-term behavior will be modeled with the tapped delay lines of a time-delay neural network (TDNN). This network takes the coefficients of the orthogonal expansion of the approximating polynomial as inputs such considering short-term and long-term information efficiently. The advantages of the method will be demonstrated by means of artificial data and two real-world application examples, the prediction of the user number in a computer network and online tool wear classification in turning.

  7. 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.

  8. Short-term versus long-term rainfall time series in the assessment of potable water savings by using rainwater in houses.

    PubMed

    Ghisi, Enedir; Cardoso, Karla Albino; Rupp, Ricardo Forgiarini

    2012-06-15

    The main objective of this article is to assess the possibility of using short-term instead of long-term rainfall time series to evaluate the potential for potable water savings by using rainwater in houses. The analysis was performed considering rainfall data from 1960 to 1995 for the city of Santa Bárbara do Oeste, located in the state of São Paulo, southeastern Brazil. The influence of the rainfall time series, roof area, potable water demand and percentage rainwater demand on the potential for potable water savings was evaluated. The potential for potable water savings was estimated using computer simulations considering a set of long-term rainfall time series and different sets of short-term rainfall time series. The ideal rainwater tank capacity was also assessed for some cases. It was observed that the higher the percentage rainwater demand and the shorter the rainfall time series, the larger the difference between the potential for potable water savings and the greater the variation in the ideal rainwater tank size. The sets of short-term rainfall time series considered adequate for different scenarios ranged from 1 to 13 years depending on the roof area, percentage rainwater demand and potable water demand. The main finding of the research is that sets of short-term rainfall time series can be used to assess the potential for potable water savings by using rainwater, as the results obtained are similar to those obtained from the long-term rainfall time series.

  9. Time- and Dose-Dependent Effects of 17 Beta-Estradiol on Short-Term, Real-Time Proliferation and Gene Expression in Porcine Granulosa Cells

    PubMed Central

    Ciesiółka, Sylwia; Budna, Joanna; Jopek, Karol; Bryja, Artur; Kranc, Wiesława; Borys, Sylwia; Jeseta, Michal; Chachuła, Adrian; Ziółkowska, Agnieszka; Antosik, Paweł; Bukowska, Dorota; Brüssow, Klaus P.; Bruska, Małgorzata; Nowicki, Michał

    2017-01-01

    The key mechanisms responsible for achievement of full reproductive and developmental capability in mammals are the differentiation and transformation of granulosa cells (GCs) during folliculogenesis, oogenesis, and oocyte maturation. Although the role of 17 beta-estradiol (E2) in ovarian activity is widely known, its effect on proliferative capacity, gap junction connection (GJC) formation, and GCs-luteal cells transformation requires further research. Therefore, the goal of this study was to assess the real-time proliferative activity of porcine GCs in vitro in relation to connexin (Cx), luteinizing hormone receptor (LHR), follicle stimulating hormone receptor (FSHR), and aromatase (CYP19A1) expression during short-term (168 h) primary culture. The cultured GCs were exposed to acute (at 96 h of culture) and/or prolonged (between 0 and 168 h of culture) administration of 1.8 and 3.6 μM E2. The relative abundance of Cx36, Cx37, Cx40, Cx43, LHR, FSHR, and CYP19A1 mRNA was measured. We conclude that the proliferation capability of GCs in vitro is substantially associated with expression of Cxs, LHR, FSHR, and CYP19A1. Furthermore, the GC-luteal cell transformation in vitro may be significantly accompanied by the proliferative activity of GCs in pigs. PMID:28337462

  10. Circular revisit orbits design for responsive mission over a single target

    NASA Astrophysics Data System (ADS)

    Li, Taibo; Xiang, Junhua; Wang, Zhaokui; Zhang, Yulin

    2016-10-01

    The responsive orbits play a key role in addressing the mission of Operationally Responsive Space (ORS) because of their capabilities. These capabilities are usually focused on supporting specific targets as opposed to providing global coverage. One subtype of responsive orbits is repeat coverage orbit which is nearly circular in most remote sensing applications. This paper deals with a special kind of repeating ground track orbit, referred to as circular revisit orbit. Different from traditional repeat coverage orbits, a satellite on circular revisit orbit can visit a target site at both the ascending and descending stages in one revisit cycle. This typology of trajectory allows a halving of the traditional revisit time and does a favor to get useful information for responsive applications. However the previous reported numerical methods in some references often cost lots of computation or fail to obtain such orbits. To overcome this difficulty, an analytical method to determine the existence conditions of the solutions to revisit orbits is presented in this paper. To this end, the mathematical model of circular revisit orbit is established under the central gravity model and the J2 perturbation. A constraint function of the circular revisit orbit is introduced, and the monotonicity of that function has been studied. The existent conditions and the number of such orbits are naturally worked out. Taking the launch cost into consideration, optimal design model of circular revisit orbit is established to achieve a best orbit which visits a target twice a day in the morning and in the afternoon respectively for several days. The result shows that it is effective to apply circular revisit orbits in responsive application such as reconnoiter of natural disaster.

  11. 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

  12. 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.

  13. Quantum duel revisited

    NASA Astrophysics Data System (ADS)

    Schmidt, Alexandre G. M.; Paiva, Milena M.

    2012-03-01

    We revisit the quantum two-person duel. In this problem, both Alice and Bob each possess a spin-1/2 particle which models dead and alive states for each player. We review the Abbott and Flitney result—now considering non-zero α1 and α2 in order to decide if it is better for Alice to shoot or not the second time—and we also consider a duel where players do not necessarily start alive. This simple assumption allows us to explore several interesting special cases, namely how a dead player can win the duel shooting just once, or how can Bob revive Alice after one shot, and the better strategy for Alice—being either alive or in a superposition of alive and dead states—fighting a dead opponent.

  14. ``Robinson's sum rule'' revisited

    NASA Astrophysics Data System (ADS)

    Orlov, Yuri F.

    2010-02-01

    This discussion revisits two articles on synchrotron radiation damping published in 1958, one by this author and Evgeny K. Tarasov [Zh. Eksp. Teor. Fiz. 34, 651 (1958)ZETFA70044-4510; Sov. Phys. JETP 34, 449 (1958)SPHJAR0038-5646], and one by Kenneth W. Robinson [Phys. Rev. 111, 373 (1958)PHRVAO0031-899X10.1103/PhysRev.111.373]. The latter is the source of what is known as “Robinson’s sum rule.” Both present the familiar rule, but with very different proofs and calculations of concrete damping decrements. Comparative analysis of these differences reveals serious flaws in Robinson’s proof and calculations.

  15. Polite Theories Revisited

    NASA Astrophysics Data System (ADS)

    Jovanović, Dejan; Barrett, Clark

    The classic method of Nelson and Oppen for combining decision procedures requires the theories to be stably-infinite. Unfortunately, some important theories do not fall into this category (e.g. the theory of bit-vectors). To remedy this problem, previous work introduced the notion of polite theories. Polite theories can be combined with any other theory using an extension of the Nelson-Oppen approach. In this paper we revisit the notion of polite theories, fixing a subtle flaw in the original definition. We give a new combination theorem which specifies the degree to which politeness is preserved when combining polite theories. We also give conditions under which politeness is preserved when instantiating theories by identifying two sorts. These results lead to a more general variant of the theorem for combining multiple polite theories.

  16. Effective string theory revisited

    NASA Astrophysics Data System (ADS)

    Dubovsky, Sergei; Flauger, Raphael; Gorbenko, Victor

    2012-09-01

    We revisit the effective field theory of long relativistic strings such as confining flux tubes in QCD. We derive the Polchinski-Strominger interaction by a calculation in static gauge. This interaction implies that a non-critical string which initially oscillates in one direction gets excited in orthogonal directions as well. In static gauge no additional term in the effective action is needed to obtain this effect. It results from a one-loop calculation using the Nambu-Goto action. Non-linearly realized Lorentz symmetry is manifest at all stages in dimensional regularization. We also explain that independent of the number of dimensions non-covariant counterterms have to be added to the action in the commonly used zeta-function regularization.

  17. Enthalpy-Entropy Compensation (EEC) Effect: A Revisit.

    PubMed

    Pan, Animesh; Biswas, Tapas; Rakshit, Animesh K; Moulik, Satya P

    2015-12-31

    A short account of the developments and perspectives of IKR (iso-kinetic relation) and EEC (enthalpy (H) - entropy (S) compensation) has been presented. The IKR and EEC are known to be extra thermodynamic or empirical correlations though linear H-S correlation can be thermodynamically deduced. Attempt has also been made to explain the phenomena in terms of statistical thermodynamics. In this study, we have briefly revisited the fundamentals of both IKR and EEC from kinetic and thermodynamic grounds. A detailed revisit of the EEC phenomenon on varied kinetic and equilibrium processes has been also presented. Possible correlations among the free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes of different similar and nonsimilar chemical processes under varied conditions have been discussed with possible future projections.

  18. Non-water-suppressed short-echo-time magnetic resonance spectroscopic imaging using a concentric ring k-space trajectory.

    PubMed

    Emir, Uzay E; Burns, Brian; Chiew, Mark; Jezzard, Peter; Thomas, M Albert

    2017-03-08

    Water-suppressed MRS acquisition techniques have been the standard MRS approach used in research and for clinical scanning to date. The acquisition of a non-water-suppressed MRS spectrum is used for artefact correction, reconstruction of phased-array coil data and metabolite quantification. Here, a two-scan metabolite-cycling magnetic resonance spectroscopic imaging (MRSI) scheme that does not use water suppression is demonstrated and evaluated. Specifically, the feasibility of acquiring and quantifying short-echo (TE  = 14 ms), two-dimensional stimulated echo acquisition mode (STEAM) MRSI spectra in the motor cortex is demonstrated on a 3 T MRI system. The increase in measurement time from the metabolite-cycling is counterbalanced by a time-efficient concentric ring k-space trajectory. To validate the technique, water-suppressed MRSI acquisitions were also performed for comparison. The proposed non-water-suppressed metabolite-cycling MRSI technique was tested for detection and correction of resonance frequency drifts due to subject motion and/or hardware instability, and the feasibility of high-resolution metabolic mapping over a whole brain slice was assessed. Our results show that the metabolite spectra and estimated concentrations are in agreement between non-water-suppressed and water-suppressed techniques. The achieved spectral quality, signal-to-noise ratio (SNR) > 20 and linewidth <7 Hz allowed reliable metabolic mapping of five major brain metabolites in the motor cortex with an in-plane resolution of 10 × 10 mm(2) in 8 min and with a Cramér-Rao lower bound of less than 20% using LCModel analysis. In addition, the high SNR of the water peak of the non-water-suppressed technique enabled voxel-wise single-scan frequency, phase and eddy current correction. These findings demonstrate that our non-water-suppressed metabolite-cycling MRSI technique can perform robustly on 3 T MRI systems and within a clinically feasible acquisition time.

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

    PubMed

    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 athlete's 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 defender's 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

  20. Contribution of pluri-annual electrical time laps survey to the understanding of short and long term landslide dynamics

    NASA Astrophysics Data System (ADS)

    Levy, C.; Zerathe, S.; Lebourg, T.

    2012-04-01

    The "Vence" landslide (0.8 million m3, south eastern France) is active since the 1970s and develops in a sandy-clay Eocene layer overlying a highly fractured and faulted Jurassic limestone. This peculiar geology explains the complex hydrology of the site which plays a key-role in the destabilization of the slope (water circulation within the sliding mass, fluid exchanges between superficial layers and deep karstic aquifer through faults). To understand fluid circulations within the unstable slope, a 4 years multi-parametric survey was set up. The survey combines Electrical Resistivity Tomography (2 daily acquisitions) and rainfall records since 2006, four boreholes monitoring groundwater levels as well as clinometers and temperature measurements since 2009. Our first approach was to study the evolution of the mean apparent resistivity. This method does not require time-consuming inversions (especially for 4 years of data) and is not affected by accuracy problems link to the inversion process. Results show that, at short time-scale, the correlation between the rainfall rate, the piezometric elevation and the mean resistivity variations is representative of two hydrogeological answers to rainfalls events: small resistivity variations related to subsurface water infiltrations with a delay of few hours after the rain, strong resistivity variations with a delay of few days after the rain highlighting the influence of the drained limestone fault systems in the landslide water supply. Results also show the need to consider the landslide answer at longer time scale, since the amplitude of deformation is strongly dependent on the massif state prior the rainfall event (e.g. piezometric levels). However, the complex link between apparent resistivity variations and real subsurface processes restricts a quantitative behavior characterization of the various geological units (drainage zones, weathered superficial layer…) and does not allow their location. To achieve better

  1. Successful operation of continuous reactors at short retention times results in high-density, fast-rate Dehalococcoides dechlorinating cultures.

    PubMed

    Delgado, Anca G; Fajardo-Williams, Devyn; Popat, Sudeep C; Torres, César I; Krajmalnik-Brown, Rosa

    2014-03-01

    The discovery of Dehalococcoides mccartyi reducing perchloroethene and trichloroethene (TCE) to ethene was a key landmark for bioremediation applications at contaminated sites. D. mccartyi-containing cultures are typically grown in batch-fed reactors. On the other hand, continuous cultivation of these microorganisms has been described only at long hydraulic retention times (HRTs). We report the cultivation of a representative D. mccartyi-containing culture in continuous stirred-tank reactors (CSTRs) at a short, 3-d HRT, using TCE as the electron acceptor. We successfully operated 3-d HRT CSTRs for up to 120 days and observed sustained dechlorination of TCE at influent concentrations of 1 and 2 mM TCE to ≥ 97 % ethene, coupled to the production of 10(12) D. mccartyi cells Lculture (-1). These outcomes were possible in part by using a medium with low bicarbonate concentrations (5 mM) to minimize the excessive proliferation of microorganisms that use bicarbonate as an electron acceptor and compete with D. mccartyi for H2. The maximum conversion rates for the CSTR-produced culture were 0.13 ± 0.016, 0.06 ± 0.018, and 0.02 ± 0.007 mmol Cl(-) Lculture (-1) h(-1), respectively, for TCE, cis-dichloroethene, and vinyl chloride. The CSTR operation described here provides the fastest laboratory cultivation rate of high-cell density Dehalococcoides cultures reported in the literature to date. This cultivation method provides a fundamental scientific platform for potential future operations of such a system at larger scales.

  2. Influence of short-time imidacloprid and acetamiprid application on soil microbial metabolic activity and enzymatic activity.

    PubMed

    Wang, Fei; Yao, Jun; Chen, Huilun; Yi, Zhengji; Choi, Martin M F

    2014-09-01

    The influence of two neonicotinoids, i.e., imidacloprid (IMI) and acetamiprid (ACE), on soil microbial activities was investigated in a short period of time using a combination of the microcalorimetric approach and enzyme tests. Thermodynamic parameters such as Q T (J g(-1) soil), ∆H met (kJ mol(-1)), J Q/S (J g(-1) h(-1)), k (h(-1)), and soil enzymatic activities, dehydrogenase, phosphomonoesterase, arginine deaminase, and urease, were used to evaluate whole metabolic activity changes and acute toxicity following IMI and ACE treatment. Various profiles of thermogenic curves reflect different soil microbial activities. The microbial growth rate constant k, total heat evolution Q T (expect for IMI), and inhibitory ratio I show linear relationship with the doses of IMI and ACE. Q T for IMI increases at 0.0-20 μg g(-1) and then decreases at 20-80 μg g(-1), possibly attributing to the presence of tolerant microorganisms. The 50 % inhibitory ratios (IC50) of IMI and ACE are 95.7 and 77.2 μg g(-1), respectively. ACE displays slightly higher toxicity than IMI. Plots of k and Q T against microbial biomass-C indicate that the k and Q T are growth yield-dependent. IMI and ACE show 29.6; 40.4 and 23.0; and 23.3, 21.7, and 30.5 % inhibition of dehydrogenase, phosphomonoesterase, and urease activity, respectively. By contrast, the arginine deaminase activity is enhanced by 15.2 and 13.2 % with IMI and ACE, respectively. The parametric indices selected give a quantitative dose-response relationship of both insecticides and indicate that ACE is more toxic than IMI due to their difference in molecular structures.

  3. A novel peak detection approach with chemical noise removal using short-time FFT for prOTOF MS data.

    PubMed

    Zhang, Shuqin; Wang, Honghui; Zhou, Xiaobo; Hoehn, Gerard T; DeGraba, Thomas J; Gonzales, Denise A; Suffredini, Anthony F; Ching, Wai-Ki; Ng, Michael K; Wong, Stephen T C

    2009-08-01

    Peak detection is a pivotal first step in biomarker discovery from MS data and can significantly influence the results of downstream data analysis steps. We developed a novel automatic peak detection method for prOTOF MS data, which does not require a priori knowledge of protein masses. Random noise is removed by an undecimated wavelet transform and chemical noise is attenuated by an adaptive short-time discrete Fourier transform. Isotopic peaks corresponding to a single protein are combined by extracting an envelope over them. Depending on the S/N, the desired peaks in each individual spectrum are detected and those with the highest intensity among their peak clusters are recorded. The common peaks among all the spectra are identified by choosing an appropriate cut-off threshold in the complete linkage hierarchical clustering. To remove the 1 Da shifting of the peaks, the peak corresponding to the same protein is determined as the detected peak with the largest number among its neighborhood. We validated this method using a data set of serial peptide and protein calibration standards. Compared with MoverZ program, our new method detects more peaks and significantly enhances S/N of the peak after the chemical noise removal. We then successfully applied this method to a data set from prOTOF MS spectra of albumin and albumin-bound proteins from serum samples of 59 patients with carotid artery disease compared to vascular disease-free patients to detect peaks with S/N> or =2. Our method is easily implemented and is highly effective to define peaks that will be used for disease classification or to highlight potential biomarkers.

  4. Second-phase validation study of short time exposure test for assessment of eye irritation potency of chemicals.

    PubMed

    Kojima, Hajime; Hayashi, Kazuhiko; Sakaguchi, Hitoshi; Omori, Takashi; Otoizumi, Takuya; Sozu, Takashi; Kuwahara, Hirofumi; Hayashi, Takumi; Sakaguchi, Mayumi; Toyoda, Akemi; Goto, Haruka; Watanabe, Shinichi; Ahiko, Kyoko; Nakamura, Tsuneaki; Morimoto, Takashi

    2013-09-01

    A Short Time Exposure (STE) test is a cytotoxicity test that uses SIRC cells (rabbit corneal cell line) to assess eye irritation potency following a 5-min chemical exposure. This second-phase validation study assessed the predictive capacity of the STE test using 40 coded test substances at three laboratories. A Validation Management Team (VMT) then evaluated the predictivity of the STE test for United Nation (UN) Globally Harmonized System (GHS) categories using 63 test substances including the results of the first-phase validation study. The STE test can assess not only the severe or corrosive ocular irritants (corresponding to the UN GHS Category 1) but also non-irritant (corresponding to UN GHS Non Category) from other toxicity classes, especially for limited types of test substances. The predictivity by STE test, however, was insufficient for identification of UN GHS categories (Category 1, Category 2, or Non Category). These results suggest that the STE test can be recommended as an initial step in a top-down approach to identification of severe irritants and test substances that require classification for eye irritation (UN GHS Category 1) as well as an initial step in a bottom-up approach to identification of test substances that do not require classification for eye irritation (UN GHS Non Category) from other toxicity classes, especially for limited types of test substances. On the other hand, the STE test is not considered adequate for the identification of mild or moderate irritants (i.e., UN GHS Categories 2A and 2B) and severe irritants (UN GHS Category 1).

  5. Revisiting Interpretation of Canonical Correlation Analysis: A Tutorial and Demonstration of Canonical Commonality Analysis

    ERIC Educational Resources Information Center

    Nimon, Kim; Henson, Robin K.; Gates, Michael S.

    2010-01-01

    In the face of multicollinearity, researchers face challenges interpreting canonical correlation analysis (CCA) results. Although standardized function and structure coefficients provide insight into the canonical variates produced, they fall short when researchers want to fully report canonical effects. This article revisits the interpretation of…

  6. Revisiting Evidence for Modularity and Functional Equivalence across Verbal and Spatial Domains in Memory

    ERIC Educational Resources Information Center

    Guerard, Katherine; Tremblay, Sebastien

    2008-01-01

    The authors revisited evidence in favor of modularity and of functional equivalence between the processing of verbal and spatial information in short-term memory. This was done by investigating the patterns of intrusions, omissions, transpositions, and fill-ins in verbal and spatial serial recall and order reconstruction tasks under control,…

  7. A voxel-based investigation for MRI-only radiotherapy of the brain using ultra short echo times

    NASA Astrophysics Data System (ADS)

    Edmund, Jens M.; Kjer, Hans M.; Van Leemput, Koen; Hansen, Rasmus H.; Andersen, Jon AL; Andreasen, Daniel

    2014-12-01

    Radiotherapy (RT) based on magnetic resonance imaging (MRI) as the only modality, so-called MRI-only RT, would remove the systematic registration error between MR and computed tomography (CT), and provide co-registered MRI for assessment of treatment response and adaptive RT. Electron densities, however, need to be assigned to the MRI images for dose calculation and patient setup based on digitally reconstructed radiographs (DRRs). Here, we investigate the geometric and dosimetric performance for a number of popular voxel-based methods to generate a so-called pseudo CT (pCT). Five patients receiving cranial irradiation, each containing a co-registered MRI and CT scan, were included. An ultra short echo time MRI sequence for bone visualization was used. Six methods were investigated for three popular types of voxel-based approaches; (1) threshold-based segmentation, (2) Bayesian segmentation and (3) statistical regression. Each approach contained two methods. Approach 1 used bulk density assignment of MRI voxels into air, soft tissue and bone based on logical masks and the transverse relaxation time T2 of the bone. Approach 2 used similar bulk density assignments with Bayesian statistics including or excluding additional spatial information. Approach 3 used a statistical regression correlating MRI voxels with their corresponding CT voxels. A similar photon and proton treatment plan was generated for a target positioned between the nasal cavity and the brainstem for all patients. The CT agreement with the pCT of each method was quantified and compared with the other methods geometrically and dosimetrically using both a number of reported metrics and introducing some novel metrics. The best geometrical agreement with CT was obtained with the statistical regression methods which performed significantly better than the threshold and Bayesian segmentation methods (excluding spatial information). All methods agreed significantly better with CT than a reference water MRI

  8. Three-dimensional accurate detection of lung emphysema in rats using ultra-short and zero echo time MRI.

    PubMed

    Bianchi, Andrea; Tibiletti, Marta; Kjørstad, Åsmund; Birk, Gerald; Schad, Lothar R; Stierstorfer, Birgit; Rasche, Volker; Stiller, Detlef

    2015-11-01

    Emphysema is a life-threatening pathology that causes irreversible destruction of alveolar walls. In vivo imaging techniques play a fundamental role in the early non-invasive pre-clinical and clinical detection and longitudinal follow-up of this pathology. In the present study, we aimed to evaluate the feasibility of using high resolution radial three-dimensional (3D) zero echo time (ZTE) and 3D ultra-short echo time (UTE) MRI to accurately detect lung pathomorphological changes in a rodent model of emphysema.Porcine pancreas elastase (PPE) was intratracheally administered to the rats to produce the emphysematous changes. 3D ZTE MRI, low and high definition 3D UTE MRI and micro-computed tomography images were acquired 4 weeks after the PPE challenge. Signal-to-noise ratios (SNRs) were measured in PPE-treated and control rats. T2* values were computed from low definition 3D UTE MRI. Histomorphometric measurements were made after euthanizing the animals. Both ZTE and UTE MR images showed a significant decrease in the SNR measured in PPE-treated lungs compared with controls, due to the pathomorphological changes taking place in the challenged lungs. A significant decrease in T2* values in PPE-challenged animals compared with controls was measured using UTE MRI. Histomorphometric measurements showed a significant increase in the mean linear intercept in PPE-treated lungs. UTE yielded significantly higher SNR compared with ZTE (14% and 30% higher in PPE-treated and non-PPE-treated lungs, respectively).This study showed that optimized 3D radial UTE and ZTE MRI can provide lung images of excellent quality, with high isotropic spatial resolution (400 µm) and SNR in parenchymal tissue (>25) and negligible motion artifacts in freely breathing animals. These techniques were shown to be useful non-invasive instruments to accurately and reliably detect the pathomorphological alterations taking place in emphysematous lungs, without incurring the risks of cumulative radiation

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

    DOEpatents

    Veligdan, James T.

    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.

  10. The generalized Langevin equation revisited: Analytical expressions for the persistence dynamics of a viscous fluid under a time dependent external force

    NASA Astrophysics Data System (ADS)

    Olivares-Rivas, Wilmer; Colmenares, Pedro J.

    2016-09-01

    The non-static generalized Langevin equation and its corresponding Fokker-Planck equation for the position of a viscous fluid particle were solved in closed form for a time dependent external force. Its solution for a constant external force was obtained analytically. The non-Markovian stochastic differential equation, associated to the dynamics of the position under a colored noise, was then applied to the description of the dynamics and persistence time of particles constrained within absorbing barriers. Comparisons with molecular dynamics were very satisfactory.

  11. Preservation of bioactive compounds of a green vegetable smoothie using short time-high temperature mild thermal treatment.

    PubMed

    Castillejo, Noelia; Martínez-Hernández, Ginés Benito; Monaco, Kamila; Gómez, Perla A; Aguayo, Encarna; Artés, Francisco; Artés-Hernández, Francisco

    2017-01-01

    Smoothies represent an excellent and convenient alternative to promote the daily consumption of fruit and vegetables in order to obtain their health-promoting benefits. Accordingly, a green fresh vegetables smoothie (77.2% cucumber, 12% broccoli and 6% spinach) rich in health-promoting compounds was developed. Soluble solids content, pH and titratable acidity of the smoothie were 4.3 ± 0.4°Bx, 4.49 ± 0.01 and 0.22 ± 0.02 mg citric acid 100(-1) g fw, respectively. Two thermal treatments to reduce microbial loads and preserve quality were assayed: T1 (3 min at 80 ℃) and T2 (45 s at 90 ℃). Fresh blended unheated samples were used as control (CTRL). The smoothie presented a viscoelastic behaviour. T1 and T2 treatments reduced initial microbial loads by 1.3-2.4 and 1.4-3.1 log units, respectively. Samples were stored in darkness at 5 and 15 ℃. Colour and physicochemical changes were reduced in thermal-treated samples throughout storage, which were better preserved at 5 ℃ rather than at 15 ℃. Vitamin C changes during storage were fitted with a Weibullian distribution. Total vitamin C losses of T1 and T2 samples during storage at 15 ℃ were greatly reduced when they were stored at 5 ℃. Initial total phenolic content (151.1 ± 4.04 mg kg(-1) fw) was 44 and 36% increased after T1 and T2 treatments, respectively. The 3-p-coumaroyl quinic and chlorogenic acids accounted the 84.7 and 7.1% relative abundance, respectively. Total antioxidant capacity (234.2 ± 20.3 mg Trolox equivalent kg(-1) fw) remained constant after the thermal treatments and was better maintained during storage in thermal-treated samples. Glucobrassicin accounted the 81% of the initial total glucosinolates content (117.8 ± 22.2 mg kg(-1) fw) of the smoothie. No glucosinolates losses were observed after T2 treatment being better preserved in thermal-treated samples. Conclusively, a short time-high temperature mild thermal treatment (T2

  12. Isn't It About Time?

    SciTech Connect

    Kuchar, Olga A.; Hoeft, TJ J.; Havre, Susan L.; Perrine, Kenneth A.

    2006-05-01

    Time plays a key role in all aspects of the intelligence analysis process, from data ingest through analysis methods to the cognitive processes that create intelligence products; however, the concept of time is difficult to grasp and not yet fully understood. Today's analytic tools fall short of satisfying the needs of analysts; these tools do not significantly facilitate an analyst's cognitive process when assembling the pieces of a puzzle together since opportunities for analysts to exploit the time dimension of their data are curtailed by the implicit representation of time found in these tools and their visualizations. There is a need to revisit and understand how time plays a role. In this paper, we briefly discuss why time is hard, the need for visualizations and interactions to deal with time, and conclude with some thoughts about a temporal analytic discourse. Overall, time cannot be left as an afterthought when developing visualizations; time must instead be well represented and highly interactable.

  13. 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…

  14. Effects of timing of corn silage supplementation on ruminal digestion, fermentation pattern and nutrient flow during continuous culture fermentation of a short and intensive orchardgrass herbage meal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a dual-flow continuous culture fermenter system, this study evaluated the effect of timing of corn silage supplementation on ruminal digestion and nutrient flows of a short and intensive orchardgrass herbage meal. Fermenters were operated over four 10-d periods. Treatments included: 28 g DM of...

  15. 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…

  16. Changes in Children's Perception-Action Tuning over Short Time Scales: Bicycling across Traffic-Filled Intersections in a Virtual Environment

    ERIC Educational Resources Information Center

    Plumert, Jodie M.; Kearney, Joseph K.; Cremer, James F.; Recker, Kara M.; Strutt, Jonathan

    2011-01-01

    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. Children (10- 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…

  17. Variation in the ability of a long day followed by a short day photoperiod signal to initiate reproductive activity in ewes at different times of the year.

    PubMed

    Sweeney, T; Donovan, A; Roche, J F; O'Callaghan, D

    1997-01-01

    Three experiments examined the importance of the time and duration of exposure to a long day followed by a short day photoperiod signal in initiating reproductive activity in ewes. In Expt 1, ewes were maintained on short days (8.5 h light:15.5 h dark) from 21 December interrupted with either 105 long days (18 h light:6 h dark; LD) from 9 February or 35 LD from 9 February, 16 March or 20 April. Exposure to long days followed by short days advanced the onset of reproductive activity in comparison to control ewes maintained on simulated natural photoperiod. Exposure to long days for 105 days delayed the onset of reproductive activity (August 2 +/- 3 days; P < 0.05) compared with 35 days beginning on the same date (July 13 +/- 5 days). The interval from the end of the long day signal to the onset of reproductive activity was shorter (P < 0.001) however, after 105 LD than after 35 LD. In Expt 2, control ewes were moved from natural photoperiod to simulated natural photoperiod on 1 November and subsequently exposed to short days from 21 December. Four other groups were also exposed to this basic photoperiodic signal sequence but it was interrupted with either 70 LD from 16 November, or 35 LD from 16 November, 21 December or 20 April. More ewes (P < 0.05) initiated reproductive activity after exposure to 70 LD from 16 November and 35 LD from 21 December or 20 April compared with control ewes maintained on short days or ewes given 35 LD from 16 November. The interval from the end of long days to the onset of reproductive activity was less (P < 0.01) in ewes given 70 LD than in ewes given 35 LD. In Expt 3, ewes on natural photoperiod were given either 90 LD from 21 September, 35 LD from 21 September, 26 October, 30 November, 4 January or 8 February followed by short days. The majority of ewes that received long followed by short days after the winter solstice resumed reproductive activity. However, all photoperiod signals given between the autumn equinox and the winter

  18. Sex differences in the Kimchi-Palmer task revisited: Global reaction times, but not number of global choices differ between adult men and women.

    PubMed

    Scheuringer, Andrea; Pletzer, Belinda

    2016-10-15

    Research, directly assessing sex-dependent differences in global versus local processing is sparse, but predominantly suggesting that men show a stronger global processing bias than women. Utilizing the Kimchi-Palmer task however, sex differences in the number of global choices can only be found in children, but not in adults. In the current study 52 men and 46 women completed a computerized version of the Kimchi Palmer task, in order to investigate whether sex-differences in global-local processing in the Kimchi-Palmer task are reflected in choice reaction times rather than choices per se. While no sex differences were found in the number of global choices, we found that especially women are faster in making local choices than men, while men are faster in making global choices than women. We did not find support for the assumption that this sex difference was modulated by menstrual cycle phase of women, since the difference between reaction times to global and local choices was consistent across the menstrual cycle of women. Accordingly there was no relationship between progesterone and global-local processing in the Kimchi-Palmer task. However, like in studies utilizing the Navon task, testosterone was positively related to the number of global choices in both men and women. To our knowledge, this is the first study including reaction times as outcome measure in a Kimchi Palmer paradigm and also the first study demonstrating sex differences in the Kimchi Palmer task in adults.

  19. Short time dynamics determine glass forming ability in a glass transition two-level model: A stochastic approach using Kramers' escape formula

    NASA Astrophysics Data System (ADS)

    Toledo-Marín, J. Quetzalcóatl; Naumis, Gerardo G.

    2017-03-01

    The relationship between short and long time relaxation dynamics is obtained for a simple solvable two-level energy landscape model of a glass. This is done through means of the Kramers' transition theory, which arises in a very natural manner to calculate transition rates between wells. Then the corresponding stochastic master equation is analytically solved to find the population of metastable states. A relation between the cooling rate, the characteristic relaxation time, and the population of metastable states is found from the solution of such equation. From this, a relationship between the relaxation times and the frequency of oscillation at the metastable states, i.e., the short time dynamics, is obtained. Since the model is able to capture either a glass transition or a crystallization depending on the cooling rate, this gives a conceptual framework in which to discuss some aspects of rigidity theory, for example.

  20. Short-pulsed diode lasers as an excitation source for time-resolved fluorescence applications and confocal laser scanning microscopy in PDT

    NASA Astrophysics Data System (ADS)

    Kress, Matthias; Meier, Thomas H.; El-Tayeb, Tarek A. A.; Kemkemer, Ralf; Steiner, Rudolf W.; Rueck, Angelika C.

    2001-11-01

    This article describes a setup for subcellular time-resolved fluorescence spectroscopy and fluorescence lifetime measurements using a confocal laser scanning microscope in combination with a short pulsed diode laser for fluorescence excitation and specimen illumination. The diode laser emits pulses at 398 nm wavelength with 70 ps full width at half maximum (FWHM) duration. The diode laser can be run at a pulse repetition rate of 40 MHz down to single shot mode. For time resolved spectroscopy a spectrometer setup consisting of an Czerny Turner spectrometer and a MCP-gated and -intensified CCD camera was used. Subcellular fluorescence lifetime measurements were achieved using a time-correlated single photon counting (TCSPC) module instead of the spectrometer setup. The capability of the short pulsed diode laser for fluorescence imaging, fluorescence lifetime measurements and time-resolved spectroscopy in combination with laser scanning microscopy is demonstrated by fluorescence analysis of several photosensitizers on a single cell level.

  1. Revisiting caspases in sepsis

    PubMed Central

    Aziz, M; Jacob, A; Wang, P

    2014-01-01

    Sepsis is a life-threatening illness that occurs due to an abnormal host immune network which extends through the initial widespread and overwhelming inflammation, and culminates at the late stage of immunosupression. Recently, interest has been shifted toward therapies aimed at reversing the accompanying periods of immune suppression. Studies in experimental animals and critically ill patients have demonstrated that increased apoptosis of lymphoid organs and some parenchymal tissues contributes to this immune suppression, anergy and organ dysfunction. Immediate to the discoveries of the intracellular proteases, caspases for the induction of apoptosis and inflammation, and their striking roles in sepsis have been focused elaborately in a number of original and review articles. Here we revisited the different aspects of caspases in terms of apoptosis, pyroptosis, necroptosis and inflammation and focused their links in sepsis by reviewing several recent findings. In addition, we have documented striking perspectives which not only rewrite the pathophysiology, but also modernize our understanding for developing novel therapeutics against sepsis. PMID:25412304

  2. 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.

  3. Dynamic causal modelling revisited.

    PubMed

    Friston, K J; Preller, Katrin H; Mathys, Chris; Cagnan, Hayriye; Heinzle, Jakob; Razi, Adeel; Zeidman, Peter

    2017-02-17

    This paper revisits the dynamic causal modelling of fMRI timeseries by replacing the usual (Taylor) approximation to neuronal dynamics with a neural mass model of the canonical microcircuit. This provides a generative or dynamic causal model of laminar specific responses that can generate haemodynamic and electrophysiological measurements. In principle, this allows the fusion of haemodynamic and (event related or induced) electrophysiological responses. Furthermore, it enables Bayesian model comparison of competing hypotheses about physiologically plausible synaptic effects; for example, does attentional modulation act on superficial or deep pyramidal cells - or both? In this technical note, we describe the resulting dynamic causal model and provide an illustrative application to the attention to visual motion dataset used in previous papers. Our focus here is on how to answer long-standing questions in fMRI; for example, do haemodynamic responses reflect extrinsic (afferent) input from distant cortical regions, or do they reflect intrinsic (recurrent) neuronal activity? To what extent do inhibitory interneurons contribute to neurovascular coupling? What is the relationship between haemodynamic responses and the frequency of induced neuronal activity? This paper does not pretend to answer these questions; rather it shows how they can be addressed using neural mass models of fMRI timeseries.

  4. 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

  5. Revisited: Decomposition or melting? Formation mechanism investigation of LiCoO2 via in-situ time-resolved X-ray diffraction.

    PubMed

    Wicker, Scott A; Walker, Edwin H

    2013-02-18

    We report the first in-situ time-resolved X-ray diffraction investigation in conjunction with a non-isothermal kinetic study using the model-free isoconversional kinetic method to determine the formation mechanism for the solid-state synthesis of electrochemically active LiCoO(2) from Li(2)CO(3) and Co(3)O(4). Detailed information on the phase evolution as well as thermal events during the heating process was clearly observed, explained, and supported. This investigation provides structural as well as kinetic evidence for a multistep reaction and proposes the first plausible formation mechanism for the solid-state synthesis of LiCoO(2).

  6. Intelligent Diagnosis of Open and Short Circuit Faults in Electric Drive Inverters For Real-Time Applications

    DTIC Science & Technology

    2009-03-03

    in this paper. In this paper the short circuit fault condition in the induction motor is simulated in a closed-loop control environment. In a...scope of this paper. Unless the motor control algorithm is altered properly during unbalanced condition , the motor drive system can undergo damage...the induction motor , and E is the battery voltage. The authors used this model to simulate 15 different faulty conditions , namely, 6 classes of

  7. Design considerations for a high-power, short rise-time pulser for thick-transducer applications

    NASA Astrophysics Data System (ADS)

    Gammell, Paul M.; Harris, Gerald R.

    2002-05-01

    When transiently-excited, thick ultrasonic source transducers are used in NDE applications, such as broadband measurements of attenuation or of directivity and frequency responses of receiving transducers, the pulser must provide an excitation pulse that is very short and of high voltage and current. Also, it is desirable that the pulser be of simple and stable design. Features of several designs, including modern FET pulser circuits, are discussed.

  8. 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.

  9. Benjamin Franklin and Mesmerism, revisited.

    PubMed

    McConkey, Kevin M; Perry, Campbell

    2002-10-01

    The authors revisit and update their previous historiographical note (McConkey & Perry, 1985) on Benjamin Franklin's involvement with and investigation of animal magnetism or mesmerism. They incorporate more recent literature and offer additional comment about Franklin's role in and views about mesmerism. Franklin had a higher degree of personal involvement with and a more detailed opinion of mesmerism than has been previously appreciated.

  10. Cultural Warping of Childbirth, Revisited

    PubMed Central

    Budin, Wendy C.

    2007-01-01

    In this column, the editor of The Journal of Perinatal Education revisits Doris Haire's classic 1972 article, “The Cultural Warping of Childbirth,” and describes the birth culture of today. The editor also describes the contents of this issue, which offer a broad range of resources, research, and inspiration for childbirth educators in their efforts to promote normal birth.

  11. The "Mushroom Cloud" Demonstration Revisited

    ERIC Educational Resources Information Center

    Panzarasa, Guido; Sparnacci, Katia

    2013-01-01

    A revisitation of the classical "mushroom cloud" demonstration is described. Instead of aniline and benzoyl peroxide, the proposed reaction involves household chemicals such as alpha-pinene (turpentine oil) and trichloroisocyanuric acid ("Trichlor") giving an impressive demonstration of oxidation and combustion reactions that…

  12. Revisiting the 1761 Transatlantic Tsunami

    NASA Astrophysics Data System (ADS)

    Baptista, Maria Ana; Wronna, Martin; Miranda, Jorge Miguel

    2016-04-01

    The tsunami catalogs of the Atlantic include two transatlantic tsunamis in the 18th century the well known 1st November 1755 and the 31st March 1761. The 31st March 1761 earthquake struck Portugal, Spain, and Morocco. The earthquake occurred around noontime in Lisbon alarming the inhabitants and throwing down ruins of the past 1st November 1755 earthquake. According to several sources, the earthquake was followed by a tsunami observed as far as Cornwall (United Kingdom), Cork (Ireland) and Barbados (Caribbean). The analysis of macroseismic information and its compatibility with tsunami travel time information led to a source area close to the Ampere Seamount with an estimated epicenter circa 34.5°N 13°W. The estimated magnitude of the earthquake was 8.5. In this study, we revisit the tsunami observations, and we include a report from Cadiz not used before. We use the results of the compilation of the multi-beam bathymetric data, that covers the area between 34°N - 38°N and 12.5°W - 5.5°W and use the recent tectonic map published for the Southwest Iberian Margin to select among possible source scenarios. Finally, we use a non-linear shallow water model that includes the discretization and explicit leap-frog finite difference scheme to solve the shallow water equations in the spherical or Cartesian coordinate to compute tsunami waveforms and tsunami inundation and check the results against the historical descriptions to infer the source of the event. This study received funding from project ASTARTE- Assessment Strategy and Risk Reduction for Tsunamis in Europe a collaborative project Grant 603839, FP7-ENV2013 6.4-3

  13. Maximum swimming speeds of sailfish and three other large marine predatory fish species based on muscle contraction time and stride length: a myth revisited

    PubMed Central

    Svendsen, Morten B. S.; Domenici, Paolo; Marras, Stefano; Krause, Jens; Boswell, Kevin M.; Rodriguez-Pinto, Ivan; Wilson, Alexander D. M.; Kurvers, Ralf H. J. M.; Viblanc, Paul E.; Finger, Jean S.; Steffensen, John F.

    2016-01-01

    ABSTRACT Billfishes are considered to be among the fastest swimmers in the oceans. Previous studies have estimated maximum speed of sailfish and black marlin at around 35 m s−1 but theoretical work on cavitation predicts that such extreme speed is unlikely. Here we investigated maximum speed of sailfish, and three other large marine pelagic predatory fish species, by measuring the twitch contraction time of anaerobic swimming muscle. The highest estimated maximum swimming speeds were found in sailfish (8.3±1.4 m s−1), followed by barracuda (6.2±1.0 m s−1), little tunny (5.6±0.2 m s−1) and dorado (4.0±0.9 m s−1); although size-corrected performance was highest in little tunny and lowest in sailfish. Contrary to previously reported estimates, our results suggest that sailfish are incapable of exceeding swimming speeds of 10-15 m s−1, which corresponds to the speed at which cavitation is predicted to occur, with destructive consequences for fin tissues. PMID:27543056

  14. Maximum swimming speeds of sailfish and three other large marine predatory fish species based on muscle contraction time and stride length: a myth revisited.

    PubMed

    Svendsen, Morten B S; Domenici, Paolo; Marras, Stefano; Krause, Jens; Boswell, Kevin M; Rodriguez-Pinto, Ivan; Wilson, Alexander D M; Kurvers, Ralf H J M; Viblanc, Paul E; Finger, Jean S; Steffensen, John F

    2016-10-15

    Billfishes are considered to be among the fastest swimmers in the oceans. Previous studies have estimated maximum speed of sailfish and black marlin at around 35 m s(-1) but theoretical work on cavitation predicts that such extreme speed is unlikely. Here we investigated maximum speed of sailfish, and three other large marine pelagic predatory fish species, by measuring the twitch contraction time of anaerobic swimming muscle. The highest estimated maximum swimming speeds were found in sailfish (8.3±1.4 m s(-1)), followed by barracuda (6.2±1.0 m s(-1)), little tunny (5.6±0.2 m s(-1)) and dorado (4.0±0.9 m s(-1)); although size-corrected performance was highest in little tunny and lowest in sailfish. Contrary to previously reported estimates, our results suggest that sailfish are incapable of exceeding swimming speeds of 10-15 m s(-1), which corresponds to the speed at which cavitation is predicted to occur, with destructive consequences for fin tissues.

  15. 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 Å 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 Ǻ 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.

  16. 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.

  17. 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

  18. 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.

  19. Acute inhalation toxicity of carbon monoxide and hydrogen cyanide revisited: Comparison of models to disentangle the concentration × time conundrum of lethality and incapacitation.

    PubMed

    Pauluhn, Juergen

    2016-10-01

    Contemporary emergency response planning guidelines are stratified to consider the threshold for serious toxicity and/or impairment of escape, relative to the potentially lethal level above this threshold and the lower level at which individuals should not experience or develop effects more serious than mild irritation. While harmonized testing guidelines and risk assessment paradigms are available for the quantification of thresholds for lethality or establishing no adverse effect levels, the quantification of 'impairment of escape' appears to be a more elusive goal. Approaches were explored in context with CO and HCN in past experimental combustion toxicology studies to estimate the time available for escape. This point of departure (POD) was compared with the non-lethal threshold (LC01) and one third thereof from published recent acute inhalation studies in rats examining the Cxt-matrix of both CO and HCN. The findings from this analysis suggest that the rat delivers the most consistent data. However, it remains challenging yet to bridge the behavioral variables of human behavior typical of escape to any surrogate animal model. For the asphyxiant gases examined, the PODs characterizing 'impairment of escape' were difficult to distinguish from those indicative of impending death. No specific modeled carboxyhemoglobin (COHb) level could be linked to onset of incapacitation. In summary, the higher ventilation of rats (kg body weight adjusted) renders this species even more susceptible than heavy breathing humans. LCt01 × 1/3 values derived from the comprehensive Cxt matrix of rat inhalation studies are considered to be most suitable and robust to estimate the human equivalent threshold (POD) of 'impairment of escape'.

  20. Eruptions with short run-up times: review of controlling factors inspired by the unexpected eruption of Calbuco volcano, April 2015, (Southern Andes)

    NASA Astrophysics Data System (ADS)

    Lara, L.; Esperger, S.

    2015-12-01

    Signs of unrest are usually detected in active volcanoes before the onset of eruptions. However, a few eruptions start suddenly without evident precursory activity or very short run-up time. The latter poses a challenge to volcano observatories regarding the capability to issue early warnings. Calbuco (42°S, Southern Andes) explosive event in April 2015 is a recent case where clear signs of unrest were detected shortly before the eruption of an andesitic magma (57% SiO2). In fact, although isolated low magnitude VT events were recorded 2 months before, the base level was only disturbed 3 hours before by an emergent seismic swarm of M<2.5 VT events, followed by 30 minutes of escalating LP and HB events. Calbuco erupted after 54 years of quiescence and no ground deformation was detected by InSAR or ground-based methods before the eruption. This short precursory activity is comparable to run-up times observed in basaltic to andesitic volcanoes. Previous authors have proposed a relationship between repose and run-up times. Repose time seems to be related with dynamics of plumbing systems (recharge and storage) and thus depends on the magma viscosity and hence magma composition. Others have shown that correlation between repose and run-up times is dependent of volcano typology. Here we expand the catalog and consider other factors as the crustal thickness, physical properties of the country rocks, depth of magma chambers and tectonic regime for all the reported eruptions with existing information. Our findings show that eruptions preceded by an extremely short unrest period occur mostly under conditions of favorable (tectonically-controlled) magma pathways unclamping, even in high-silica systems with large repose times.

  1. Richards model revisited: validation by and application to infection dynamics.

    PubMed

    Wang, Xiang-Sheng; Wu, Jianhong; Yang, Yong

    2012-11-21

    Ever since Richards proposed his flexible growth function more than half a century ago, it has been a mystery that this empirical function has made many incredible coincidences with real ecological or epidemic data even though one of its parameters (i.e., the exponential term) does not seem to have clear biological meaning. It is therefore a natural challenge to mathematical biologists to provide an explanation of the interesting coincidences and a biological interpretation of the parameter. Here we start from a simple epidemic SIR model to revisit Richards model via an intrinsic relation between both models. Especially, we prove that the exponential term in the Richards model has a one-to-one nonlinear correspondence to the basic reproduction number of the SIR model. This one-to-one relation provides us an explicit formula in calculating the basic reproduction number. Another biological significance of our study is the observation that the peak time is approximately just a serial interval after the turning point. Moreover, we provide an explicit relation between final outbreak size, basic reproduction number and the peak epidemic size which means that we can predict the final outbreak size shortly after the peak time. Finally, we introduce a constraint in Richards model to address over fitting problem observed in the existing studies and then apply our method with constraint to conduct some validation analysis using the data of recent outbreaks of prototype infectious diseases such as Canada 2009 H1N1 outbreak, GTA 2003 SARS outbreak, Singapore 2005 dengue outbreak, and Taiwan 2003 SARS outbreak. Our new formula gives much more stable and precise estimate of model parameters and key epidemic characteristics such as the final outbreak size, the basic reproduction number, and the turning point, compared with earlier simulations without constraints.

  2. "In Loco Parentis" Revisited?

    ERIC Educational Resources Information Center

    Murphree, Carolyn T.

    1986-01-01

    Suggests that many students are not aware of proper etiquette and proposes that business communication instructors offer a short bibliography and a few tips that can help students acquire more polish. (DF)

  3. Nutational Damping Revisited

    NASA Astrophysics Data System (ADS)

    Burns, J. A.; Sharma, I.

    2000-10-01

    Motivated by the recent detection of complex rotational states for several asteroids and comets, as well as by the ongoing and planned spacecraft missions to such bodies, which should allow their rotational states to be accurately determined, we revisit the problem of the nutational damping of small solar system bodies. The nutational damping of asteroids has been approximately analyzed by Prendergast (1958), Burns and Safronov (1973), and Efroimsky and Lazarian (2000). Many other similar dynamical studies concern planetary wobble decay (e.g., Peale 1973; Yoder and Ward 1979), interstellar dust grain alignment (e.g., Purcell 1979; Lazarian and Efroimsky 1999) and damping of Earth's Chandler wobble (Lambeck 1980). Recall that rotational energy loss for an isolated body aligns the body's angular momentum vector with its axis of maximum inertia. Assuming anelastic dissipation, simple dimensional analysis determines a functional form of the damping timescale, on which all the above authors agree. However, the numerical coefficients of published results are claimed to differ by orders of magnitude. Differences have been ascribed to absent physics, to solutions that fail to satisfy boundary conditions perfectly, and to unphysical choices for the Q parameter. The true reasons for the discrepancy are unclear since, despite contrary claims, the full 3D problem (nutational damping of an anelastic ellipsoid) is analytically intractable so far. To move the debate forward, we compare the solution of a related 2D problem to the expressions found previously, and we present results from a finite element model. On this basis, we feel that previous rates for the decay of asteroidal tumbling (Harris 1994), derived from Burns and Safronov (1973), are likely to be accurate, at least to a factor of a few. Funded by NASA.

  4. Highly controlled synthesis of nanometric gold particles by citrate reduction using the short mixing, heating and quenching times achievable in a microfluidic device

    NASA Astrophysics Data System (ADS)

    Ftouni, Jamal; Penhoat, Maël; Addad, Ahmed; Payen, Edmond; Rolando, Christian; Girardon, Jean-Sébastien

    2012-07-01

    Homodispersed 1.8 nm gold nanoparticles were obtained reproducibly in high yields using the classical Turkevich protocol at a high concentration in a continuous flow capillary reactor. The microfluidic reactor made from commercially available items permitted short mixing, heating and quenching times which are the key parameters of this synthesis.Homodispersed 1.8 nm gold nanoparticles were obtained reproducibly in high yields using the classical Turkevich protocol at a high concentration in a continuous flow capillary reactor. The microfluidic reactor made from commercially available items permitted short mixing, heating and quenching times which are the key parameters of this synthesis. Electronic supplementary information (ESI) available: Description of the microfluidic device, protocol for gold nanoparticle synthesis in batch and in the microsystem, and gold nanoparticle size distribution raw data. See DOI: 10.1039/c2nr11666a

  5. Clinical use of an epinephrine-reduced (1/400,000) articaine solution in short-time dental routine treatments--a multicenter study.

    PubMed

    Daubländer, Monika; Kämmerer, Peer W; Willershausen, Brita; Leckel, Michael; Lauer, Hans-Christoph; Buff, Siegmar; Rösl, Benita

    2012-08-01

    The addition of epinephrine in dental local anaesthesia results in a longer and deeper anaesthesia under almost ischemic conditions. For short-time dental treatments, epinephrine-reduced anaesthetics may offer shorter and more individual anaesthesia with reduced potential side effects. The aim of this study was a clinical evaluation of anaesthetic potency and adverse effects of an epinephrine-reduced articaine formulation in dental patients undergoing short-time routine treatment. In a prospective clinical, not interventional, study between January 2008 and February 2009, 908 patients undergoing short-time dental treatment in five medical centers were anaesthetized with 4% articaine 1:400,000 epinephrine (Ubistesin, 3M/ESPE, Seefeld, Germany). Efficacy and safety in clinical use were evaluated. A follow-up after 1 day was conducted by telephone survey. A mean amount of 1.3-ml anaesthetic solution was needed to achieve a complete or sufficient anaesthesia in 97% (n = 876) of cases. A second injection had to be done in 3.7% (n = 34) before and in 11.9% (n = 108) during treatment. Here, the second injection had to be applied after a mean of 48.6 min. The mean duration of soft tissue anaesthesia after infiltration was 146.6 min, after nerve block 187.7 min. The painful treatment took a mean of 50.2 min and the total treatment time summed up to 68.8 min. In 1.7% cases (n = 15), unwanted side effects were observed. The results indicate that a lower concentration of epinephrine in combination with the 4% articaine solution leads to a high success rate of efficacy. The clinical use of a 4% articaine 1:400,000 epinephrine solution can be stated as safe and effective in short dental routine treatments. Reconsiderations concerning limitations of indication or additional contraindications are not necessary.

  6. Phase transitions and critical phenomena in the two-dimensional Ising model with dipole interactions: A short-time dynamics study.

    PubMed

    Horowitz, C M; Bab, M A; Mazzini, M; Rubio Puzzo, M L; Saracco, G P

    2015-10-01

    The ferromagnetic Ising model with antiferromagnetic dipole interactions is investigated by means of Monte Carlo simulations, focusing on the characterization of the phase transitions between the tetragonal liquid and stripe of width h phases. The dynamic evolution of the physical observables is analyzed within the short-time regime for 0.5≤δ≤1.3, where δ is the ratio between the short-range exchange and the long-range dipole interaction constants. The obtained results for the interval 0.5≤δ≤1.2 indicate that the phase transition line between the h=1 stripe and tetragonal liquid phases is continuous. This finding contributes to clarifying the controversy about the order of this transition. This controversy arises from the difficulties introduced in the simulations due to the presence of long-range dipole interactions, such as an important increase in the simulation times that limits the system size used, strong finite size effects, as well as to the existence of multiple metastable states at low temperatures. The study of the short-time dynamics of the model allows us to avoid these hindrances. Moreover, due to the fact that the finite-size effects do not significantly affect the power-law behavior exhibited in the observables within the short-time regime, the results could be attributed to those corresponding to the thermodynamic limit. As a consequence of this, a careful characterization of the critical behavior for the whole transition line is performed by giving the complete set of critical exponents.

  7. Tendons – time to revisit inflammation

    PubMed Central

    Rees, Jonathan D; Stride, Matthew; Scott, Alex

    2014-01-01

    It is currently widely accepted among clinicians that chronic tendinopathy is caused by a degenerative process devoid of inflammation. Current treatment strategies are focused on physical treatments, peritendinous or intratendinous injections of blood or blood products and interruption of painful stimuli. Results have been at best, moderately good and at worst a failure. The evidence for non-infammatory degenerative processes alone as the cause of tendinopathy is surprisingly weak. There is convincing evidence that the inflammatory response is a key component of chronic tendinopathy. Newer anti-inflammatory modalities may provide alternative potential opportunities in treating chronic tendinopathies and should be explored further. PMID:23476034

  8. From detection to deflection: Mitigation techniques for hidden global threats of natural space objects with short warning time

    NASA Astrophysics Data System (ADS)

    Hussein, Alaa; Rozenheck, Oshri; Entrena Utrilla, Carlos Manuel

    2016-09-01

    Throughout recorded history, hundreds of Earth impacts have been reported, with some catastrophic localized consequences. Based on the International Space University (ISU) Planetary Defense project named READI, we address the impact event problem by giving recommendations for the development of a planetary defense program. This paper reviews the current detection and tracking techniques and gives a set of recommendations for a better preparation to shield Earth from asteroid and cometary impacts. We also extend the use of current deflection techniques and propose a new compilation of those to deflect medium-sized potentially hazardous objects (PHOs). Using an array of techniques from high-energy lasers to defensive missiles, we present a set of protective layers to defend our planet. The paper focused on threats with a short warning period from discovery to impact with Earth, within few years.

  9. 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.

  10. The short-time treatment with curcumin sufficiently decreases cell viability, induces apoptosis and copper enhances these effects in multidrug-resistant K562/A02 cells.

    PubMed

    Lu, Jin-Jian; Cai, Yu-Jun; Ding, Jian

    2012-01-01

    The anti-cancer activities of curcumin (CUR), a polyphenol derived from the plant Curcuma longa, has been extensively studied. In the present study, we found that CUR displayed anti-multidrug-resistant (MDR) activity in K562/A02 cells. A short-time treatment with CUR sufficiently and equally induced DNA damage, decreased cell viability, and triggered apoptosis in parent K562 and MDR K562/A02 cells. The short-time treatment with CUR also caused decrease of pro-caspase 3 in both cell lines and decrease of pro-caspase 9, increase of PARP cleavage and the ratio of Bax/Bcl-xL in MDR K562/A02 cells. Further experiment revealed that CUR was capable of down-regulating P-glycoprotein in MDR K562/A02 cells. Moreover, we observed that Cu(2+) enhanced CUR-mediated apoptosis which was blocked by antioxidants N-acetyl-cysteine and catalase. In summary, the short-time treatment with CUR sufficiently induced DNA damage, decreased cell viability and triggered apoptosis in MDR K562/A02 cells and Cu(2+) enhanced CUR-mediated apoptosis which due to reactive oxygen species generation.

  11. Extension of recovery time from fatigue by repeated rest with short-term sleep during continuous fatigue load: Development of chronic fatigue model.

    PubMed

    Kanzaki, Akinori; Okauchi, Takashi; Hu, Di; Shingaki, Tomotaka; Katayama, Yumiko; Koyama, Hidenori; Watanabe, Yasuyoshi; Cui, Yilong

    2016-05-01

    Homeostasis is known to be involved in maintaining the optimal internal environment, helping to achieve the best performance of biological functions. At the same time, a deviation from optimal conditions often attenuates the performance of biological functions, and such restricted performance could be considered as individual fatigue, including physical and mental fatigue. The present study seeks to develop an animal model of chronic or subacute fatigue in which the recovery time is extended through the gradual disruption of homeostasis. We show that repeated short-term rest periods with certain lengths of sleep during continuous fatigue loading extend recovery from spontaneous nighttime activity but not physical performance in comparison with a continuous fatigue-loading procedure. Furthermore, the immobility time in a forced swimming test was extended by repeated short-term rests. These results suggest that repeated short-term rest with certain lengths of sleep during continuous fatigue loading is able to extend the recovery from mental fatigue but not from physical fatigue and that this effect might occur via the disruption of a homeostatic mechanism that is involved in restoring the optimal internal environment.

  12. Short stature

    MedlinePlus

    Idiopathic short stature; Non-growth hormone deficient short stature ... syndrome Turner syndrome Williams syndrome Other reasons include: Growth hormone deficiency Infections of the developing baby before birth ...

  13. Enceladus' tidal dissipation revisited

    NASA Astrophysics Data System (ADS)

    Tobie, Gabriel; Behounkova, Marie; Choblet, Gael; Cadek, Ondrej; Soucek, Ondrej

    2016-10-01

    A series of chemical and physical evidence indicates that the intense activity at Enceladus' South Pole is related to a subsurface salty water reservoir underneath the tectonically active ice shell. The detection of a significant libration implies that this water reservoir is global and that the average ice shell thickness is about 20-25km (Thomas et al. 2016). The interpretation of gravity and topography data further predicts large variations in ice shell thickness, resulting in a shell potentially thinner than 5 km in the South Polar Terrain (SPT) (Cadek et al. 2016). Such an ice shell structure requires a very strong heat source in the interior, with a focusing mechanism at the SPT. Thermal diffusion through the ice shell implies that at least 25-30 GW is lost into space by passive diffusion, implying a very efficient dissipation mechanism in Enceladus' interior to maintain such an ocean/ice configuration thermally stable.In order to determine in which conditions such a large dissipation power may be generated, we model the tidal response of Enceladus including variable ice shell thickness. For the rock core, we consider a wide range of rheological parameters representative of water-saturated porous rock materials. We demonstrate that the thinning toward the South Pole leads to a strong increase in heat production in the ice shell, with a optimal thickness obtained between 1.5 and 3 km, depending on the assumed ice viscosity. Our results imply that the heat production in the ice shell within the SPT may be sufficient to counterbalance the heat loss by diffusion and to power eruption activity. However, outside the SPT, a strong dissipation in the porous core is required to counterbalance the diffusive heat loss. We show that about 20 GW can be generated in the core, for an effective viscosity of 1012 Pa.s, which is comparable to the effective viscosity estimated in water-saturated glacial tills on Earth. We will discuss the implications of this revisited tidal

  14. 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

  15. Development of a system for real-time measurements of metabolite transport in plants using short-lived positron-emitting radiotracers

    NASA Astrophysics Data System (ADS)

    Kiser, Matthew R.

    Over the past 200 years, the Earth's atmospheric carbon dioxide (CO 2) concentration has increased by more than 35%, and climate experts predict that CO2 levels may double by the end of this century. Understanding the mechanisms of resource management in plants is fundamental for predicting how plants will respond to the increase in atmospheric CO 2. Plant productivity sustains life on Earth and is a principal component of the planet's system that regulates atmospheric CO2 concentration. As such, one of the central goals of plant science is to understand the regulatory mechanisms of plant growth in a changing environment. Short-lived positron-emitting radiotracer techniques provide time-dependent data that are critical for developing models of metabolite transport and resource distribution in plants and their microenvironments. To better understand the effects of environmental changes on resource transport and allocation in plants, we have developed a system for real-time measurements of rnetabolite transport in plants using short-lived positron-emitting radio-tracers. This thesis project includes the design, construction, and demonstration of the capabilities of this system for performing real-time measurements of metabolite transport in plants. The short-lived radiotracer system described in this dissertation takes advantage of the combined capabilities and close proximity of two research facilities at. Duke University: the Triangle Universities Nuclear Laboratory (TUNL) and the Duke University Phytotron, which are separated by approximately 100 meters. The short-lived positron-emitting radioisotopes are generated using the 10-MV tandem Van de Graaff accelerator located in the main TUNL building, which provides the capability of producing short-lived positron-emitting isotopes such as carbon-11 (11C: 20 minute half-life), nitrogen-13 (13N; 10 minute half-life), fluorine-18 (18F; 110 minute half-life), and oxygen-15 (15O; 2 minute half-life). The radioisotopes may

  16. Devils Hole, Nevada: revisited

    NASA Astrophysics Data System (ADS)

    Spötl, C.; Dublyansky, Y.

    2012-04-01

    Among the ever increasing number of caves visited and studied by paleoclimate scientists around the globe one site is special for a number of reasons. First described in the literature in 1988, Devils Hole is a geometrically simple cave developed along an extensional fracture in the Amargosa Desert of SW Nevada. The deeper portion of this cavity is phreatic and part of a regional aquifer whose lowest discharge point is Death Valley. Landmark studies by Ike Winograd's team examined thick calcite crusts present on the walls of this and a neighboring cave (termed Devils Hole #2) and retrieved one of the most remarkable (and thought-provoking) isotope proxy records covering the last half million of years (1992). More recently, Coplen (2007) scrutinized the stable isotope systematics at Devils Hole. His results suggest that this setting represents a rare example of inorganic calcite precipitation essentially at isotopic equilibrium. We obtained permission from the Death Valley National Park Service to study and sample Devils Hole #2. While previous studies were based on samples from the phreatic zone we cored the calcite crust just above the groundwater table in an attempt to extend the original record further back in time and to obtain direct paleowater isotope data. Stable isotope data obtained along one core show a very high degree of similarity with the published DH11 core and a first set of U-series dates confirms the stratigraphy down to 476 ka. Older calcite also shows glacial-interglacial oscillations in both carbon and oxygen isotopes. A tentative correlation with Antarctic and deep-sea isotope records suggests that the lower part of the calcite is ca. 800 ka old (i.e. MIS 20). The cores show petrographic evidence of falling groundwater levels during MIS 9, 7 and 5e, but there are no indications of major hiati. Interestingly, growth at our drill location ended shortly after 20 ka BP, i.e. much later than at the subaqueous site in Devils Hole proper where DH11

  17. Re-visiting the electrophysiology of language.

    PubMed

    Obleser, Jonas

    2015-09-01

    This editorial accompanies a special issue of Brain and Language re-visiting old themes and new leads in the electrophysiology of language. The event-related potential (ERP) as a series of characteristic deflections ("components") over time and their distribution on the scalp has been exploited by speech and language researchers over decades to find support for diverse psycholinguistic models. Fortunately, methodological and statistical advances have allowed human neuroscience to move beyond some of the limitations imposed when looking at the ERP only. Most importantly, we currently witness a refined and refreshed look at "event-related" (in the literal sense) brain activity that relates itself more closely to the actual neurobiology of speech and language processes. It is this imminent change in handling and interpreting electrophysiological data of speech and language experiments that this special issue intends to capture.

  18. Seasonal dating of Sappho's 'Midnight Poem' revisited

    NASA Astrophysics Data System (ADS)

    Cuntz, Manfred; Gurdemir, Levent; George, Martin

    2016-04-01

    Sappho was a Greek lyric poet who composed a significant array of pristine poetry. Although much of it has been lost, her reputation has endured thanks to numerous surviving fragments. One of her contributions includes the so-called 'Midnight Poem', which contains a line about the Pleiades, setting sometime before midnight, and supposedly observed from the island of Lesbos. This poem also refers to the setting of the Moon. Sappho's Midnight Poem thus represents a prime example of where ancient poetry and astronomy merge, and it also offers the possibility of seasonal dating. Previously, Herschberg and Mebius (1990) estimated that the poem was composed in late winter/early spring, a time frame that is not unusual for lyrics of an amorous nature. The aim of our paper is to revisit this earlier finding by using modern-day software. Our study confirms Herschberg and Mebius' result, but also conveys further information.

  19. 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

  20. First Grade Writers Revisit Their Work

    ERIC Educational Resources Information Center

    Hansen, Jane A.

    2007-01-01

    In this article, the author focuses on first grade readers and writers who revisit their work and describes what first-graders do when they revisit their writing about science and literature and review collections of their work. The first-graders discussed here are in Elaine O'Connor's classroom at Clark Elementary School in Charlottesville. In a…