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1

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

NASA Technical Reports Server (NTRS)

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

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

2

PERT Completion Times Revisited  

Microsoft Academic Search

Two sources of PERT completion time bias are well documented in the literature: near critical paths turning critical during execution and misspecified activity time probability models. Although simulation is clearly the most appropriate method for assessing project duration, most introductory discussions touch on these issues and move quickly to standard approximations, implying that PERT offers useful, if only approximate, project

Fred E. Williams

2005-01-01

3

Special Relativity and Time Travel Revisited  

E-print Network

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

Akhila Raman

2001-01-25

4

Nonlinear time-series analysis revisited  

E-print Network

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

Elizabeth Bradley; Holger Kantz

2015-03-25

5

Time to Revisit the Heterogeneous Telescope Network  

NASA Astrophysics Data System (ADS)

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.

Hessman, F. V.

6

Short Time Cycles of Purely Quantum Refrigerators  

E-print Network

Four stroke Otto refrigerator cycles with no classical analogue are studied. Extremely short cycle times with respect to the internal time scale of the working medium characterize these refrigerators. Therefore these cycles are termed sudden. The sudden cycles are characterized by the stable limit cycle which is the invariant of the global cycle propagator. During their operation the state of the working medium possesses significant coherence which is not erased in the equilibration segments due to the very short time allocated. This characteristic is reflected in a difference between the energy entropy and the Von Neumann entropy of the working medium. A classification scheme for sudden refrigerators is developed allowing simple approximations for the cooling power and coefficient of performance.

Tova Feldmann; Ronnie Kosloff

2012-04-18

7

Transient nanobubbles in short-time electrolysis  

E-print Network

Water electrolysis in a microsystem is observed and analyzed on a short-time scale ~10 us. 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 the size smallaer than 150 nm. Such bubbles disintegrate violently affecting the surface of electrodes.

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

2013-01-12

8

Transient nanobubbles in short-time electrolysis  

NASA Astrophysics Data System (ADS)

Water electrolysis in a microsystem is observed and analyzed on a short-time scale of ?10 ?s. 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.

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

2013-05-01

9

Short Time Cycles of Purely Quantum Refrigerators  

E-print Network

Four stroke Otto refrigerator cycles with no classical analogue are studied. Extremely short cycle times with respect to the internal time scale of the working medium characterize these refrigerators. Therefore these cycles are termed sudden. The sudden cycles are characterized by the stable limit cycle which is the invariant of the global cycle propagator. During their operation the state of the working medium possesses significant coherence which is not erased in the equilibration segments due to the very short time allocated. This characteristic is reflected in a difference between the energy entropy and the Von Neumann entropy of the working medium. A classification scheme for sudden refrigerators is developed allowing simple approximations for the cooling power and coefficient of performance.

Feldmann, Tova

2012-01-01

10

Universal short-time quantum critical dynamics in imaginary time  

NASA Astrophysics Data System (ADS)

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

Yin, Shuai; Mai, Peizhi; Zhong, Fan

2014-04-01

11

Short rise time intense electron beam generator  

DOEpatents

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.

Olson, Craig L. (Albuquerque, NM)

1987-01-01

12

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

E-print Network

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

Schuettpelz, Eric

13

Short time dynamics of viscous drop spreading  

NASA Astrophysics Data System (ADS)

Liquid drops start spreading directly after coming into contact with a solid substrate. Although this phenomenon involves a three-phase contact line, the spreading motion can be very fast. We experimentally study the initial spreading dynamics, characterized by the radius of the wetted area, for viscous drops. Using high-speed imaging with synchronized bottom and side views gives access to 6 decades of time resolution. We show that short time spreading does not exhibit a pure power-law growth. Instead, we find a spreading velocity that decreases logarithmically in time, with a dynamics identical to that of coalescing viscous drops. Remarkably, the contact line dissipation and wetting effects turn out to be unimportant during the initial stages of drop spreading.

Eddi, A.; Winkels, K. G.; Snoeijer, J. H.

2013-01-01

14

Failure Prevention by Short Time Corrosion Tests  

SciTech Connect

Short time corrosion testing of perforated sheets and wire meshes fabricated from Type 304L stainless steel, Alloy 600 and C276 showed that 304L stainless steel perforated sheet should perform well as the material of construction for dissolver baskets. The baskets will be exposed to hot nitric acid solutions and are limited life components. The corrosion rates of the other alloys and of wire meshes were too high for useful extended service. Test results also indicated that corrosion of the dissolver should drop quickly during the dissolutions due to the inhibiting effects of the corrosion products produced by the dissolution processes.

MICKALONIS, JOHN

2005-05-01

15

Examination of short-contact-time coal liquefaction product stability. [Short contract time liquefaction  

SciTech Connect

An experimental apparatus for producing short contact time (SCT) coal liquefaction material was assembled to replace tubing bomb microreactors. The apparatus consists of a 300 cm/sup 3/ autoclave, coal delivery equipment, temperature monitoring and control equipment, and gas traps for venting gaseous reaction products. Additionally, methods for evaluation of short contact time liquefaction products were reviewed and evaluated for applicability to this project. The results of elemental analysis; time-temperature profiles; fractionation into oils, asphaltenes, preasphaltenes, and residue; and high performance liquid chromatography (HPLC) are discussed. The applicability of the analytic methods to developing correlations relating short contact time liquefaction products to process conditions is also discussed. Finally, preliminary data from 19 cm/sup 3/ tubing bomb microreactors are discussed. Differences in operation of the 300 cm/sup 3/ autoclave and the 19 cm/sup 3/ microreactors are compared.

Wham, R.M.; Rodgers, B.R.; Frazier, G.C.

1982-01-01

16

Short-time evolution of nonlinear Klein-Gordon systems  

SciTech Connect

The short-time evolution of a class of nonlinear Klein-Gordon systems is studied. For nonzero mass, the short-time behavior of the field variable has an inverse-sine spectrum rather than an exponential one.

Guha-Roy, C.; Bagchi, B.; Sinha, D.K.

1987-04-01

17

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

E-print Network

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

Guido Parravicini; Serena Rigamonti

2010-09-23

18

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

NASA Astrophysics Data System (ADS)

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

Parravicini, Guido; Rigamonti, Serena

2011-01-01

19

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

PubMed Central

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

2012-01-01

20

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

PubMed

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

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

2012-01-01

21

Long-time behaviour of particles diffusing in strongly disordered medium, revisited  

E-print Network

L-895 Long-time behaviour of particles diffusing in strongly disordered medium, revisited Y. Shapir) Résumé. 2014 On réexamine l'argument heuristique de Lifshitz pour le comportement à longue durée de la diffusion classique dans le régime fortement désordonné. La déviation de la densité à l'origine suit un

Boyer, Edmond

22

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

SciTech Connect

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.

Zhang Fuwen; Yan Jingzhi; Wei Daming [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Shao Lang, E-mail: fwzhang@pmo.ac.cn [Department of Physics, Hebei Normal University, Shijiazhuang 050016 (China)

2012-05-10

23

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

Microsoft Academic Search

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

E. Allen Emerson; Joseph Y. Halpern

1983-01-01

24

Revisiting the effect of nicotine on interval timing.  

PubMed

This paper reviews the evidence for nicotine-induced acceleration of the internal clock when timing in the seconds-to-minutes timescale, and proposes an alternative explanation to this evidence: that nicotine reduces the threshold for responses that result in more reinforcement. These two hypotheses were tested in male Wistar rats using a novel timing task. In this task, rats were trained to seek food at one location after 8s since trial onset and at a different location after 16s. Some rats received the same reward at both times (group SAME); some received a larger reward at 16s (group DIFF). Steady baseline performance was followed by 3 days of subcutaneous nicotine administration (0.3mg/kg), baseline recovery, and an antagonist challenge (mecamylamine, 1.0mg/kg). Nicotine induced a larger, immediate reduction in latencies to switch (LTS) in group DIFF than in group SAME. This effect was sustained throughout nicotine administration. Mecamylamine pretreatment and nicotine discontinuation rapidly recovered baseline performance. These results support a response-threshold account of nicotinic disruption of timing performance, possibly mediated by nicotinic acetylcholine receptors. A detailed analysis of the distribution of LTSs suggests that anomalous effects of nicotine on LTS dispersion may be due to loss of temporal control of behavior. PMID:25637907

Daniels, Carter W; Watterson, Elizabeth; Garcia, Raul; Mazur, Gabriel J; Brackney, Ryan J; Sanabria, Federico

2015-04-15

25

Analysis of fMRI Time-Series Revisited - Again  

Microsoft Academic Search

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

K. J. Worsley; K. J. Friston

1997-01-01

26

Analysis of fMRI Time-Series Revisited  

Microsoft Academic Search

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

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

1995-01-01

27

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

E-print Network

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

Nikolay Kuznetsov; Oleg Motygin

2014-10-22

28

Short time-series microarray analysis: Methods and challenges  

PubMed Central

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

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

2008-01-01

29

Short-time oxidation of zirconium.  

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

30

Revisiting the central dogma one molecule at a time.  

PubMed

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

Bustamante, Carlos; Cheng, Wei; Mejia, Yara X; Meija, Yara X

2011-02-18

31

Revisiting the Central Dogma One Molecule at a Time  

PubMed Central

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

Bustamante, Carlos; Cheng, Wei; Meija, Yara

2011-01-01

32

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

NASA Astrophysics Data System (ADS)

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

Schneider, S.

2006-12-01

33

Controlled short residence time coal liquefaction process  

DOEpatents

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.

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

1982-05-04

34

Short-time quantum propagator and Bohmian trajectories?  

PubMed Central

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 ?t2 for the quantum propagator and we show that the quantum potential is negligible modulo ?t2 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

de Gosson, Maurice; Hiley, Basil

2013-01-01

35

Short-term load forecasting with chaos time series analysis  

Microsoft Academic Search

This paper presents a new approach to short-term load forecasting in power systems. The proposed method makes use of chaos time series analysis that is based on deterministic chaos to capture characteristics of complicated load behaviour. Deterministic chaos allows us to reconstruct a time series and determine the number of input variables. This paper describes chaos time series analysis of

Hiroyuki Mori; Shouichi Urano

1996-01-01

36

Time delay and short-range scattering in quantum waveguides  

E-print Network

Although many physical arguments account for using a modified definition of time delay in multichannel-type scattering processes, one can hardly find rigorous results on that issue in the literature. We try to fill in this gap by showing, both in an abstract setting and in a short-range case, the identity of the modified time delay and the Eisenbud-Wigner time delay in waveguides. In the short-range case we also obtain limiting absorption principles, state spectral properties of the total Hamiltonian, prove the existence of the wave operators and show an explicit formula for the S-matrix. The proofs rely on stationary and commutator methods.

Rafael Tiedra de Aldecoa

2005-04-11

37

Short-term load forecasting using a chaotic time series  

Microsoft Academic Search

dimension corresponds to the number of input variables. of the deterministic multiplayer perceptron (MLP) model of the reconstructed time series [61, [7]. A new approach to short-term load forecasting (STLF) in power systems is described in this paper. The method The MLP has been trained and then has been used for uses a chaotic time series and artificial neural network.

S. P. Michanos; A. C. Tsakoumis; P. Fessas; S. S. Vladov; V. M. Mladenov

2003-01-01

38

The Oklo bound on the time variation of the fine-structure constant revisited  

E-print Network

It has been pointed out by Shlyakhter that data from the natural fission reactors which operated about two billion years ago at Oklo (Gabon) had the potential of providing an extremely tight bound on the variability of the fine-structure constant alpha. We revisit the derivation of such a bound by: (i) reanalyzing a large selection of published rare-earth data from Oklo, (ii) critically taking into account the very large uncertainty of the temperature at which the reactors operated, and (iii) connecting in a new way (using isotope shift measurements) the Oklo-derived constraint on a possible shift of thermal neutron-capture resonances with a bound on the time variation of alpha. Our final (95% C.L.) results are: -0.9 \\times 10^{-7} <(alpha^{Oklo} - alpha^{now})/alpha <1.2\\times 10^{-7} and -6.7 \\times 10^{-17} {yr}^{-1} < {\\dot alpha}^{averaged}/alpha <5.0\\times10^{-17} {yr}^{-1}$.

Thibault Damour; Freeman Dyson

1996-06-28

39

Speech processing based on short-time Fourier analysis  

SciTech Connect

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.

Portnoff, M.R.

1981-06-02

40

Signal reconstruction from short-time Fourier transform magnitude  

Microsoft Academic Search

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

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

1983-01-01

41

A Short Term Real Time Study in Syntactic Change.  

ERIC Educational Resources Information Center

Recent research has shown that Brazilian Portuguese is undergoing a change regarding the null subject parameter, evolving from a null subject to a non-null subject language. This paper presents the results of a short term, real time study of speakers of Brazilian Portuguese with low and mid levels of formal education. The study was based on…

Duarte, Maria Eugenia Lamoglia

42

Helium speech enhancement using the short-time Fourier transform  

Microsoft Academic Search

Speech produced in a hyperbaric helium-oxygen atmosphere suffers a variety of distortions which render it virtually unintelligible. This paper describes a new system for helium speech enhancement based on a short-time Fourier transform signal representation. The algorithm is robust, allows nonlinear warping of the spectral envelope, and includes provisions for generating the enhanced speech at a reduced sampling rate. Noise

M. Richards

1982-01-01

43

Comparison of wide aperture and short residence time ion lenses  

SciTech Connect

A series of ion lens configurations were computer modeled using the program SIMION. The intermediate inversion point characteristic of ion lenses used in most analytical mass spectrometers is eliminated. The first inversion point is at the focal point of the lens. The potential gradient in the ionization region is increased substantially. This reduces the residence time of an ion in the lens, which is desirable, although it has the undesirable effect of increasing the energy spread of ions produced by electron bombardment. This energy spreading effect does not occur in sources where the ions are made on a surface, such as surface ionization, field desorption, SIMS, FAB, etc. This is determined by the potential difference across the region in which ions are produced. The importance of ion residence time comes from the kinetic energy of the ion prior to acceleration. This kinetic energy is in random directions, and defocuses the ion beam with increasing ion residence time. Two of the more promising designs were constructed and tested with rhenium ions generated by positive self surface ionization. The first lens was designed to focus ions from as wide an area as possible, consistant with a reasonable entry angle (<0.40/sup 0/) through the focal slit and a reasonably short residence time. This lens is called the Wide aperture (WA) lens. The second lens was designed to have as short a residence time as feasible consistant with a reasonable Aperture, with a larger entry angle. This lens is called the Short Residence Time (SRT) lens.

Delmore, J.E.

1984-06-01

44

Suppression of timing errors in short overdamped josephson junctions.  

PubMed

The influence of fluctuations and periodical driving on temporal characteristics of short overdamped Josephson junctions is analyzed. We obtain the standard deviation of the switching time in the presence of a dichotomous driving force for arbitrary noise intensity and in the frequency range of practical interest. For sinusoidal driving the resonant activation effect has been observed. The mean switching time and its standard deviation have a minimum as a function of driving frequency. As a consequence the optimization of the system for fast operation will simultaneously lead to the minimization of timing errors. PMID:15525111

Pankratov, Andrey L; Spagnolo, Bernardo

2004-10-22

45

Dual beta-lactam therapy for serious Gram-negative infections: is it time to revisit?  

PubMed

We are rapidly approaching a crisis in antibiotic resistance, particularly among Gram-negative pathogens. This, coupled with the slow development of novel antimicrobial agents, underscores the exigency of redeploying existing antimicrobial agents in innovative ways. One therapeutic approach that was heavily studied in the 1980s but abandoned over time is dual beta-lactam therapy. This article reviews the evidence for combination beta-lactam therapy. Overall, in vitro, animal and clinical data are positive and suggest that beta-lactam combinations produce a synergistic effect against Gram-negative pathogens that rivals that of beta-lactam-aminoglycoside or beta-lactam-fluoroquinolone combination therapy. Although the precise mechanism of improved activity is not completely understood, it is likely attributable to an enhanced affinity to the diverse penicillin-binding proteins found among Gram negatives. The collective data indicate that dual beta-lactam therapy should be revisited for serious Gram-negative infections, especially in light of the near availability of potent beta-lactamase inhibitors, which neutralize the effect of problematic beta-lactamases. PMID:25308565

Rahme, Christine; Butterfield, Jill M; Nicasio, Anthony M; Lodise, Thomas P

2014-12-01

46

Oxidative dehydrogenation of propane over monoliths at short contact times  

Microsoft Academic Search

A specially designed tubular microreactor with independent control of feed preheat as well as catalyst temperature and allowing to rapidly quench reaction products was used to test performance of supported Pt-based monolithic catalysts in the reaction of propane oxidative dehydrogenation at short contact times. To minimize the impact of undesired homogeneous reactions capable of decreasing propylene selectivity, proprietary straight-channel thin-wall

V. A Sadykov; S. N Pavlova; N. F Saputina; I. A Zolotarskii; N. A Pakhomov; E. M Moroz; V. A Kuzmin; A. V Kalinkin

2000-01-01

47

Evaluation of Scaling Invariance Embedded in Short Time Series  

PubMed Central

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

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

2014-01-01

48

Desensitization to media violence over a short period of time.  

PubMed

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

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

2009-01-01

49

Theory of the short time mechanical relaxation in articular cartilage.  

PubMed

Articular cartilage is comprised of macromolecules, proteoglycans, with (charged) chondroitin sulfate side-chains attached to them. The proteoglycans are attached to longer hyaluronic acid chains, trapped within a network of type II collagen fibrils. As a consequence of their relatively long persistence lengths, the number of persistence lengths along the chondroitin sulfate and proteoglycan chains is relatively small, and consequently, the retraction times for these side chains are also quite short. We argue that, as a consequence of this, they will not significantly inhibit the reptation of the hyaluronic acid chains. Scaling arguments applied to this model allow us to show that the shortest of the mechanical relaxation times of cartilage, that have been determined by Fyhrie and Barone to be due to reptation of the hyaluronic acid polymers, should have a dependence on the load, i.e., force per unit interface area P, carried by the cartilage, proportional to P(3/2). PMID:22070338

Ruberti, J W; Sokoloff, J B

2011-10-01

50

Common structure in panels of short ecological time-series.  

PubMed Central

Typically, in many studies in ecology, epidemiology, biomedicine and others, we are confronted with panels of short time-series of which we are interested in obtaining a biologically meaningful grouping. Here, we propose a bootstrap approach to test whether the regression functions or the variances of the error terms in a family of stochastic regression models are the same. Our general setting includes panels of time-series models as a special case. We rigorously justify the use of the test by investigating its asymptotic properties, both theoretically and through simulations. The latter confirm that for finite sample size, bootstrap provides a better approximation than classical asymptotic theory. We then apply the proposed tests to the mink-muskrat data across 81 trapping regions in Canada. Ecologically interpretable groupings are obtained, which serve as a necessary first step before a fuller biological and statistical analysis of the food chain interaction. PMID:11133038

Yao, Q; Tong, H; Finkenstädt, B; Stenseth, N C

2000-01-01

51

Evidence of short-time dynamical correlations in simple liquids  

NASA Astrophysics Data System (ADS)

We report a molecular dynamics study of the collective dynamics of a simple monatomic liquid-interacting through a two-body potential that mimics that of lithium-across the liquid-glass transition. In the glassy phase we find evidences of a fast relaxation process similar to that recently found in Lennard-Jones glasses. The origin of this process is ascribed to the topological disorder, i.e., to the dephasing of the different momentum Q Fourier components of the actual normal modes of vibration of the disordered structure. More important, we find that the fast relaxation persists in the liquid phase with almost no temperature dependence of its characteristic parameters (strength and relaxation time). We conclude, therefore, that in the liquid phase well above the melting point, at variance with the usual assumption of uncorrelated binary collisions, the short time particle motion is strongly correlated and can be described via a normal mode expansion of the atomic dynamics.

Scopigno, T.; Ruocco, G.; Sette, F.; Viliani, G.

2002-09-01

52

Asymptotically anti-de Sitter space-times: symmetries and conservation laws revisited  

E-print Network

In this short note, we verify explicitly in static coordinates that the non trivial asymptotic Killing vectors at spatial infinity for anti-de Sitter space-times correspond one to one to the conformal Killing vectors of the conformally flat metric induced on the boundary. The fall-off conditions for the metric perturbations that guarantee finiteness of the associated conserved charges are derived.

Glenn Barnich; Friedemann Brandt; Kim Claes

2003-06-25

53

Stability of short-contact-time coal liquefaction products  

SciTech Connect

The primary purpose of this project was to study short-contact-time coal liquefaction in tubing-bomb microreactors using a recycle solvent from the Lummus Integrated Two-Stage Liquefaction Process and a Kentucky No. 9 coal (without the addition of gaseous hydrogen). Experiments were conducted to relate product stability to process parameters, including the time-temperatue history of the slurry during heatup to reaction temperature and the time which the slurry remained at temperature in the reactor. The most important result of this study was the significant increases in conversion to pyridine-soluble material obtained by modifying the portion of the slurry heating curve corresponding to the preheater portion of the process. As measured by pyridine-soluble components, the yields from reactions at 700/sup 0/K (800/sup 0/F) at 5-min residence time at reaction temperature increased from 71 wt % (dry mineral matter-free coal) to 89 wt % by introducing a 2.5-min delay at 589/sup 0/K (600/sup 0/F) during heatup. Other results indicated that conversion is significantly affected by the degree of mixing; retrograde reactions were observed for reaction times greater than 10 min and a temperature of 733/sup 0/K (860/sup 0/F). The Lummus solvent used in the study appears to contain a significant fraction of polycyclic aromatics containing two to five aromatic rings.

Wham, R.M.

1984-01-01

54

Predator-prey interactions, resource depression and patch revisitation  

USGS Publications Warehouse

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.

Erwin, R.M.

1989-01-01

55

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

E-print Network

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

Rodolphe Chabreyrie; Stefan G. Llewellyn Smith

2014-05-08

56

DECISION TIME HORIZON FOR MUSIC GENRE CLASSIFICATION USING SHORT TIME FEATURES  

E-print Network

and ranking of tapped- delay-line short-time features. Late information fusion as e.g. ma- jority voting the digital age and the big record companies are starting to sell music on-line on the web. An example

57

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

E-print Network

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

Poggio, Tomaso

58

Short-time-evolved wave functions for solving quantum many-body problems  

E-print Network

converges essentially to the exact ground state in a relatively short time. Thus a short-time evolved wave function can be an excellent approximation to the exact ground state. Such a short-time-evolved wave function can be obtained by factorizing...

Ciftja, O.; Chin, Siu A.

2003-01-01

59

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

E-print Network

Single channel speech enhancement using MMSE estimation of short-time modulation magnitude spectrum.wojcicki@gmail.com Abstract In this paper we investigate the enhancement of speech by ap- plying MMSE short-time spectral domain spectral subtraction. Index Terms: speech enhancement, MMSE short-time spectral magnitude

60

Evidence of short-time dynamical correlations in simple liquids.  

PubMed

We report a molecular dynamics study of the collective dynamics of a simple monatomic liquid--interacting through a two-body potential that mimics that of lithium--across the liquid-glass transition. In the glassy phase we find evidences of a fast relaxation process similar to that recently found in Lennard-Jones glasses. The origin of this process is ascribed to the topological disorder, i.e., to the dephasing of the different momentum Q Fourier components of the actual normal modes of vibration of the disordered structure. More important, we find that the fast relaxation persists in the liquid phase with almost no temperature dependence of its characteristic parameters (strength and relaxation time). We conclude, therefore, that in the liquid phase well above the melting point, at variance with the usual assumption of uncorrelated binary collisions, the short time particle motion is strongly correlated and can be described via a normal mode expansion of the atomic dynamics. PMID:12366104

Scopigno, T; Ruocco, G; Sette, F; Viliani, G

2002-09-01

61

Short-distance space-time structure and black holes in string theory: a short review of the present status  

Microsoft Academic Search

We briefly review the present status of string theory from the viewpoint of its implications on the short-distance space-time structure and black hole physics. Special emphases are given on two closely related issues in recent developments towards nonperturbative string theory, namely, the role of the space-time uncertainty relation as a qualitative but universal characterization of the short-distance structure of string

Miao Li; Tamiaki Yoneya

1999-01-01

62

Short time-scale periodicity in OJ 287  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

63

A Method of Human Short Hair Modeling and Real Time Animation Volume Interactions  

E-print Network

A Method of Human Short Hair Modeling and Real Time Animation Yang Guang Volume Interactions 5@comp.nus.edu.sg Abstract This paper describes a method of human short hair mod- eling and real time animation. A method is proposed to model the short hair. First, a hair style model is derived from a scalp model interactively

Huang, Zhiyong

64

Drop tower Beijing and short-time microgravity experiments  

NASA Astrophysics Data System (ADS)

Being an important, large ground-based experiment facility for microgravity science, the drop tower of National Microgravity Lab, CAS was founded in 2003 and, since then, has been un-dertaking the experiments to meet the requirements in microgravity research. The 116 meters high drop tower is located in Zhong Guan Cun district, the scientific town of Beijing. Main components of the facility consist of the drop capsule, release mechanism and deceleration and recovery devices, and were developed with particular technical characteristics. Inner space of the drop tower was not vacuumed during the experiment, and a dual capsule system was adopted. The dual capsule comprises an inner and an outer capsule, and there is a space between in the evacuated atmosphere of 30 Pa. During the free fall, the outer capsule falls in normal atmospheric condition, and the inner capsule falls in vacuum. In addition, a single capsule configuration is also available for experiments w of lower gravity level. The residual acceleration is 10-5go or 10-3g0 related to dual capsule or single capsule arrangement respec-tively. An electric magnetic release system was used to release the capsule from position of 83 meters in height. The designed structure of the release mechanism guaranteed the release disturbance to be small enough. An elastic controllable decelerated system, consisted of the reversible mechanic/electric energy transducer, steel cables and rings, string bag, elastic rub-ber stringassembly, energy dissipation resistance, controlling computer system, was used in the drop tower facility. This system is effective to reduce the impact acceleration to a level of 15g0. The experiment data can be recorded by an on-board data acquisition and control system, and transmitted wirelessly to the control room. Many experiments related to the fluid physics, combustion, material science and other field have been successfully conducted by using the short-time microgravity facility of drop tower in Beijing. At present, the drop tower is play-ing important role in the research of microgravity science and application with more effective, reliable running status.

Wan, S. H.; Yin, M. G.; Guan, X. D.; Lin, H.; Xie, J. C.; Hu, Wen-Rui

65

Short-term load forecasting using time series analysis: A case study for Singapore  

Microsoft Academic Search

This paper presents time series analysis for short-term Singapore electricity demand forecasting. Two time series models are proposed, namely, the multiplicative decomposition model and the seasonal ARIMA Model. Forecasting errors of both models are computed and compared. Results show that both time series models can accurately predict the short-term Singapore demand and that the Multiplicative decomposition model slightly outperforms the

Jianguang Deng; Panida Jirutitijaroen

2010-01-01

66

ADAPTIVE SHORT-TIME ANALYSIS-SYNTHESIS FOR SPEECH ENHANCEMENT Prabahan Basu, Patrick J. Wolfe  

E-print Network

ADAPTIVE SHORT-TIME ANALYSIS-SYNTHESIS FOR SPEECH ENHANCEMENT Prabahan Basu, Patrick J. Wolfe a multiresolution short-time analysis method for speech enhancement. It is well known that fixed reso- lution-synthesis scheme for speech enhance- ment in which the adaptation is based on a measure of local time- frequency

67

Revisiting Marey’s Applications of Scientific Moving Image Technologies in the Context of Bergson’s Philosophy: Audio-Visual Mediation and the Experience of Time  

Microsoft Academic Search

This paper revisits some early applications of audio-visual imaging technologies used in physiology in a dialogue with reflections\\u000a on Henri Bergson’s philosophy. It focuses on the aspects of time and memory in relation to spatial representations of movement\\u000a measurements and critically discusses them from the perspective of the observing participant and the public exhibitions of\\u000a scientific films. Departing from an

Martha Blassnigg

2010-01-01

68

Intermittency, current flows, and short time diffusion in interacting finite sized one-dimensional fluids  

Microsoft Academic Search

Long time molecular dynamics simulations of one-dimensional Lennard-Jones systems reveal that while the diffusion coefficient of a tagged particle indeed goes to zero in the very long time, the mean-square displacement is linear with time at short to intermediate times, allowing the definition of a short time diffusion coefficient [Lebowitz and Percus, Phys. Rev. 155, 122 (1967)]. The particle trajectories

Subrata Pal; Goundla Srinivas; Sarika Bhattacharyya; Biman Bagchi

2002-01-01

69

Latitudinal Variation in Reproductive Timing of a Short-Lived Monocarp, Daucus Carota (Apiaceae)  

E-print Network

Latitudinal Variation in Reproductive Timing of a Short-Lived Monocarp, Daucus Carota (Apiaceaernerlca LATITUDINAL VARIATION IN REPRODUCTIVE TIMING OF A SHORT-LIVED MONOCARP, DAUCUS CAROTA (APIACEAE-history variation in Daucus carota along its latitudinal range in eastern North Amer- ica. Seeds collected from

Lacey, Elizabeth P.

70

Short-time nonlinear dynamical analysis of heart rate variability in dogs after acute myocardial infarction  

Microsoft Academic Search

This paper presents the concept of the short-time nonlinear dynamical analysis of heart rate variability for physiological animal experiments and pharmacological experiments as well as clinical diagnosis and prognosis. We established an animal experiment protocol of myocardial ischemia to observe the results of the short-time nonlinear dynamical analysis of heart rate variability and compared the nonlinear dynamical parameters of heart

Ming Xin Qin; Yi Min Zang; Xue Tao Shi; Feng Fu

1998-01-01

71

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

E-print Network

Speech enhancement using a minimum mean-square error short-time spectral modulation magnitude In this paper we investigate the enhancement of speech by applying MMSE short-time spectral magnitude estimation on the quality of enhanced speech, and find that this method works better with speech uncertainty. Finally we

72

Noise Driven Short-Time Phase Spectrum Compensation Procedure for Speech Enhancement  

E-print Network

Noise Driven Short-Time Phase Spectrum Compensation Procedure for Speech Enhancement Anthony P.lyons, k.paliwal}@griffith.edu.au Abstract Typical speech enhancement algorithms operate on the short- time approach to speech enhancement has been proposed where the noisy mag- nitude spectrum is recombined

73

Pattern storage and processing in attractor networks with short-time synaptic dynamics  

Microsoft Academic Search

Neurophysiological experiments show that the strength of synaptic connections can undergo substantial changes on a short time scale. These changes depend on the history of the presynaptic input. Using mean-field techniques, we study how short-time dynamics of synaptic connections influence the performance of attractor neural networks in terms of their memory capacity and capability to process external signals. For binary

Dmitri Bibitchkov; J Michael Herrmann; Theo Geisel

2002-01-01

74

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

E-print Network

14853 #12;2 Abstract Sampling rare, short-time, and reactive trajectories is of considerable interest separated by energy or entropy barriers. Simulations of activated trajectories with random sampling the barrier in short times. A boundary value formulation is proposed that selects these rare trajectories

Elber, Ron

75

Spectral Evolution of Short GRBS on sub-millisecond time scale  

NASA Astrophysics Data System (ADS)

There has been growing consensus that short and long GRBs are associated with two different populations of astrophysical sources: mergers and SN explosions, respectively. While temporal properties of short and long GRBs could be considered with similar depth and accuracy, patterns of spectral variability of the 2 classes of GRBs are much harder to compare. This is due to the fact, that short GRBs exhibit variability on time scales shorter than 1 ms and count rate, measured at such short time scales, is not sufficient for reliable spectroscopy even for the brightest events. In this situation, any new possibility to look at spectral evolution of short GRBs on sub-millisecond time scales in terms of spectral parameters, may provide more solid background for theoretical analysis. In this paper we present analysis of spectral evolution of short GRBs in terms of Band spectral function parameters, using the earlier developed Global Fit approach (GFA).

Chernenko, A.

2013-07-01

76

Transmission line distance relaying using a variable window short-time Fourier transform  

Microsoft Academic Search

This paper presents a new approach for transmission line protection using a variable window short-time Fourier transform known as S-transform. The S-transform (ST) is a time–frequency spectral localization method, similar to short-time Fourier transform (STFT), but with a Gaussian window whose width scales inversely, and whose height scales linearly with the frequency. The change in spectral energy of the ST

S. R. Samantaray; P. K. Dash

2008-01-01

77

Intrinsic short time scale variability of W3(OH) maser  

E-print Network

We have studied the OH masers in the star forming region, W3(OH), with data obtained from the Very Long Baseline Array (VLBA). The data provide an angular resolution of $\\sim$5 mas, and a velocity resolution of 106 m s$^{-1}$. A novel analysis procedure allows us to differentiate between broadband temporal intensity fluctuations introduced by instrumental gain variations plus interstellar diffractive scintillation, and intrinsic narrowband variations. Based on this 12.5 hours observation, we are sensitive to variations with time scales of minutes to hours. We find statistically significant intrinsic variations with time scales of $\\sim$15--20 minutes or slower, based on the {\\it velocity-resolved fluctuation spectra}. These variations are seen predominantly towards the line shoulders. The peak of the line profile shows little variation, suggesting that they perhaps exhibit saturated emission. The associated modulation index of the observed fluctuation varies from statistically insignificant values at the line center to about unity away from the line center. Based on light-travel-time considerations, the 20-minute time scale of intrinsic fluctuations translates to a spatial dimension of $\\sim$2--3 AU along the sight-lines. On the other hand, the transverse dimension of the sources, estimated from their observed angular sizes of about $\\sim$3 mas, is about 6 AU. We argue that these source sizes are intrinsic, and are not affected by interstellar scatter broadening. The implied peak brightness temperature of the 1612/1720 maser sources is about $\\sim2\\times 10^{13}$ K, and a factor of about five higher for the 1665 line.

R. Ramachandran; A. A. Deshpande; W. M. Goss

2006-08-04

78

A Method of Human Short Hair Modeling and Real Time Animation  

Microsoft Academic Search

This paper describes a method of human short hair modeling and real time animation. A method is proposed to model short hair. First, a hair style model is derived from a scalp model interactively. The hair model is then derived automatically from the hair style and scalp models. Texture mapping is applied to the hair model for a better visual

Yang Guang; Zhiyong Huang

2002-01-01

79

Short residence time coal liquefaction process including catalytic hydrogenation  

DOEpatents

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.

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

1982-05-18

80

Short residence time coal liquefaction process including catalytic hydrogenation  

DOEpatents

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.

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

1982-05-18

81

Short-Time-Scale Monitoring of Q 2237+0305  

NASA Astrophysics Data System (ADS)

Photometry in R and I' (similar to I) for the gravitional lens system Q 2237+0305 are presented in order to monitor the light curves of the four quasar components over a period of hours to days; i.e., the time delay over which instrinic brightness variations would be observed according to theoretical models. No variations were found of any kind during a three day period, but comparison of the R data with previously published observations provides new information on the microlensing of component B reported in 1992. This component appears to have increased in brightness by at least 0.5 mag between March and July 1991, and has decreased in brightness from the maximum by at least 0.15 mag by mid-June 1992. Light curves representing the history of the four components are discussed in detail from which the rise time for component B, < 720 days, and the event duration, >4 yr, are estimated. (SECTION: Quasars and Active Galactic Nuclei)

Cumming, Caroline M.; De Robertis, Michael M.

1995-05-01

82

Multiple Roles for Time in Short-Term Memory: Evidence from Serial Recall of Order and Timing  

ERIC Educational Resources Information Center

Three experiments are reported that examine the relationship between short-term memory for time and order information, and the more specific claim that order memory is driven by a timing signal. Participants were presented with digits spaced irregularly in time and postcued (Experiments 1 and 2) or precued (Experiment 3) to recall the order or…

Farrell, Simon

2008-01-01

83

Aggressive inverted papilloma with intracranial invasion and short malignization time.  

PubMed

Inverted papillomas (IP) are considered benign lesions with a prevalence up to 4% among all sinunasal tumors; however, invasive growth and varying tendency for malignization are reported in literature. We report the case of a 69-year-old woman suffering from a large, aggressively growing IP invading the orbit, skull base, and frontal lobe of the brain. Within only 3 months' time the papilloma showed transformation into an invasive carcinoma, leaving surgical therapy in vain due to explosive recurrence. Intracranial and intraorbital expansion by IP is possible despite histology not showing signs of malignancy initially. In "regular" IP close endoscopic follow-up is mandatory to not overlook recurrence harboring malignancy. PMID:23984212

Tomazic, Peter Valentin; Stammberger, Heinz; Habermann, Walter; Schmid, Christoph; Koele, Wolfgang; Mokry, Michael; Gellner, Verena; Beham, Alfred

2011-11-01

84

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

PubMed Central

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

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

2013-01-01

85

Short-time dynamics of an Ising system on fractal structures  

NASA Astrophysics Data System (ADS)

The short-time critical relaxation of an Ising model on a Sierpinski carpet is investigated using Monte Carlo simulation. We find that when the system is quenched from high temperature to the critical temperature, the evolution of the order parameter and its persistence probability, the susceptibility, and the autocorrelation function all show power-law scaling behavior at the short-time regime. The results suggest that the spatial heterogeneity and the fractal nature of the underlying structure do not influence the scaling behavior of the short-time critical dynamics. The critical temperature, dynamic exponent z, and other equilibrium critical exponents ? and ? of the fractal spin system are determined accurately using conventional Monte Carlo simulation algorithms. The mechanism for short-time dynamic scaling is discussed.

Zheng, Guang-Ping; Li, Mo

2000-11-01

86

High voltage electrical amplifier having a short rise time  

DOEpatents

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.

Christie, David J. (Pleasanton, CA); Dallum, Gregory E. (Livermore, CA)

1991-01-01

87

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

ERIC Educational Resources Information Center

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

Getchell, Nancy; Pabreja, Priya

2006-01-01

88

Time-domain magnetic resonance studies of short-lived radical pairs in liquid solution  

Microsoft Academic Search

Magnetic resonance spectra of radical-ion pairs possessing lifetimes as short as 12 ns have been obtained using a new time-resolved optically detected magnetic resonance technique. Short-lived radical pairs are produced by a laser flash. The transient optical absorbance of the radical pairs or the triplet products resulting from their collapse is monitored as a function of time in the presence

Michael R. Wasielewski; James R. Norris; Michael K. Bowman

1984-01-01

89

Short-time critical dynamics and universality on a two-dimensional Triangular Lattice  

E-print Network

Critical scaling and universality in short-time dynamics for spin models on a two-dimensional triangular lattice are investigated by using Monte Carlo simulation. Emphasis is placed on the dynamic evolution from fully ordered initialstates to show that universal scaling exists already in the short-time regime in form of power-law behavior of the magnetization and Binder cumulant. The results measured for the dynamic and static critical exponents, $\\theta$, $z$, $\\beta$ and $\

H. P. Ying; L. Wang; J. B Zhang; M. Jiang; J. Hu

2001-02-27

90

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

PubMed

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). PMID:25381597

Greene, Kaylin M; Maggs, Jennifer L

2014-11-01

91

Prediction of Long and Short Time Rheological Behavior in Soft Glassy Materials  

NASA Astrophysics Data System (ADS)

We present an effective time approach to predict long and short time rheological behavior of soft glassy materials from experiments carried out over practical time scales. Effective time approach takes advantage of relaxation time dependence on aging time that allows time-aging time superposition even when aging occurs over the experimental time scales. Interestingly, experiments on a variety of soft materials demonstrate that the effective time approach successfully predicts superposition for diverse aging regimes ranging from subaging to hyperaging behaviors. This approach can also be used to predict behavior of any response function in molecular as well as spin glasses.

Shahin, A.; Joshi, Yogesh M.

2011-01-01

92

A Method to Modify RMT using Short-Time Behavior in Chaotic Systems  

E-print Network

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

A. Matthew Smith; Lev Kaplan

2009-07-29

93

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

PubMed Central

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

2013-01-01

94

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

E-print Network

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

A. Matthew Smith; Lev Kaplan

2010-06-29

95

Frequency-selective quantitation of short-echo time 1H magnetic resonance spectra.  

PubMed

Accurate and efficient filtering techniques are required to suppress large nuisance components present in short-echo time magnetic resonance (MR) spectra. This paper discusses two powerful filtering techniques used in long-echo time MR spectral quantitation, the maximum-phase FIR filter (MP-FIR) and the Hankel-Lanczos Singular Value Decomposition with Partial ReOrthogonalization (HLSVD-PRO), and shows that they can be applied to their more complex short-echo time spectral counterparts. Both filters are validated and compared through extensive simulations. Their properties are discussed. In particular, the capability of MP-FIR for dealing with macromolecular components is emphasized. Although this property does not make a large difference for long-echo time MR spectra, it can be important when quantifying short-echo time spectra. PMID:17433741

Poullet, Jean-Baptiste; Sima, Diana M; Van Huffel, Sabine; Van Hecke, Paul

2007-06-01

96

Frequency-selective quantitation of short-echo time 1H magnetic resonance spectra  

NASA Astrophysics Data System (ADS)

Accurate and efficient filtering techniques are required to suppress large nuisance components present in short-echo time magnetic resonance (MR) spectra. This paper discusses two powerful filtering techniques used in long-echo time MR spectral quantitation, the maximum-phase FIR filter (MP-FIR) and the Hankel-Lanczos Singular Value Decomposition with Partial ReOrthogonalization (HLSVD-PRO), and shows that they can be applied to their more complex short-echo time spectral counterparts. Both filters are validated and compared through extensive simulations. Their properties are discussed. In particular, the capability of MP-FIR for dealing with macromolecular components is emphasized. Although this property does not make a large difference for long-echo time MR spectra, it can be important when quantifying short-echo time spectra.

Poullet, Jean-Baptiste; Sima, Diana M.; Van Huffel, Sabine; Van Hecke, Paul

2007-06-01

97

Revisiting random walks in fractal media: On the occurrence of time discrete scale invariance  

NASA Astrophysics Data System (ADS)

This paper addresses the kinetic behavior of random walks in fractal media. We perform extensive numerical simulations of both single and annihilating random walkers on several Sierpinski carpets, in order to study the time behavior of three observables: the average number of distinct sites visited by a single walker, the mean-square displacement from the origin, and the density of annihilating random walkers. We found that the time behavior of those observables is given by a power law modulated by soft logarithmic-periodic oscillations. We conjecture that logarithmic-periodic oscillations are a manifestation of a time domain discrete scale iNvariance (DSI) that occurs as a consequence of the spatial DSI of the substrate. Our conjecture implies that the logarithmic periods of oscillations in space and time domains are linked by a dynamic exponent z, through z =log(?)/log(b1), where ? and b1 are the fundamental scaling ratios of the DSI symmetry in the time and space domains, respectively. We use this relationship in order to compute z for different observables and fractals. Furthermore, we check the values obtained with independent measurements provided by the power-law behavior of the mean-square displacement with time [R2(t)?t2/z]. The very good agreement obtained between both computations of the z exponent gives strong support to the idea of an intimate interplay between spatial and time symmetry properties that we expect will have a quite general scope. We expect that the application of the outlined concepts in the field of dynamic processes in fractal media will stimulate further research.

Bab, M. A.; Fabricius, G.; Albano, Ezequiel V.

2008-01-01

98

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

ERIC Educational Resources Information Center

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…

Morawska, Alina; Sanders, Matthew

2011-01-01

99

Active mode-locking of mid-infrared quantum cascade lasers with short gain recovery time.  

PubMed

We investigate the dynamics of actively modulated mid-infrared quantum cascade lasers (QCLs) using space- and time-domain simulations of coupled density matrix and Maxwell equations with resonant tunneling current taken into account. We show that it is possible to achieve active mode locking and stable generation of picosecond pulses in high performance QCLs with a vertical laser transition and a short gain recovery time by bias modulation of a short section of a monolithic Fabry-Perot cavity. In fact, active mode locking in QCLs with a short gain recovery time turns out to be more robust to the variation of parameters as compared to previously studied lasers with a long gain recovery time. We investigate the effects of spatial hole burning and phase locking on the laser output. PMID:25836455

Wang, Yongrui; Belyanin, Alexey

2015-02-23

100

Short time-scale effects in the pulsed source thermal lens  

Microsoft Academic Search

The pressure and density disturbances which develop in a gas after the absorption of a short laser pulse of gaussian radial profile have been analysed in terms of the characteristic times for pressure wave propagation and vibrational-translational energy transfer for the absorber molecules. The relative time scales of other processes affecting the disturbance have also been considered. Experimental results, in

R. T. Bailey; F. R. Cruickshank; R. Guthrie; D. Pugh; I. J. M. Weir

1983-01-01

101

Fast range imaging by CMOS sensor array through multiple double short time integration (MDSI)  

Microsoft Academic Search

The presented novel approach for direct range image acquisition is based on a CMOS image sensor with extremely short integration time and a defined flash illumination by fast infrared laser diodes. Determining the light propagation time by the MDSI method on a chip, a single CMOS sensor chip measures simultaneously distances to a net of numerous target points in a

Peter Mengel; Giinter Doemens; L. Listl

2001-01-01

102

Time series prediction of short term scintillations of Ku band satellite links in Sri Lanka  

Microsoft Academic Search

Scintillation effect is a dominant atmospheric impairment among the various contributing factors for low fade margin communication systems operating on high frequency bands such as Ku. Empirical analysis of scintillations can be done using signal strength measurements which can be treated as a time series prediction problem in forecasting the short-term scintillation effect. This paper discusses the time series based

Uthpala Premarathne; K. Samarasinghe

2010-01-01

103

Automated Control and Monitoring of Thermal Processing Using High Temperature, Short Time Pasteurization  

Microsoft Academic Search

High temperature, short time pasteurization was used to evaluate a computer-based system for con- trolling 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 multivaria- ble. The

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

1997-01-01

104

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

E-print Network

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

105

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

NASA Technical Reports Server (NTRS)

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.

Hannaford, Blake; Lehman, Steven

1986-01-01

106

Effect of squeezing and Planck constant dependence in short time semiclassical entanglement  

NASA Astrophysics Data System (ADS)

In this paper, we investigate into the short time semiclassical entanglement of a general class of two-coupled harmonic oscillator system that includes additional nonlinear terms in the potential of the form ? x m y n , such that the sum of the degree m and n equals to a fixed constant. An analytical expression of the short time linear entropy is derived and it shows a clear relationship between the single mode squeezing and the entanglement dynamics. In addition to that, our theoretical analysis has shown that the short time semiclassical entanglement entropy displays a dependence on the Planck constant ? of the form ? m + n - 2 for this class of systems. By applying our results to the linearly coupled harmonic oscillator, the Barbanis-Contopoulos, the Hénon-Heiles and the Pullen-Edmonds Hamiltonian, we have found a good correspondence between the numerical and analytical results in the short-time regime. Interestingly, our results have demonstrated both analytically and numerically that an appropriate manipulation of initial squeezing can have the significant effect of enhancing the short time semiclassical entanglement between the two subsystems.

Joseph, Sijo K.; Chew, Lock Yue; Sanjuan, Miguel A. F.

2014-08-01

107

ZeroRelaxationTime Limits in the Hydrodynamic Equations for Plasmas Revisited  

E-print Network

­Poisson system: @ t n ff + @ x j ff = 0 (1) m ff @ t j ff +m ff @ x (j 2 ff =n ff ) + @ x p ff (n ff ) = \\Gammaq ff n ff @ x OE \\Gamma m ff j ff ø ff ; (2) \\Gammaâ?? 2 @ xx OE = n i \\Gamma n e ; (3) where ff = e; i relaxation time constants for electrons and ions, respectively. The pressure functions p ff are usually

Jüngel, Ansgar

108

Analysis of fMRI Time-Series Revisited—Again  

Microsoft Academic Search

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

K. J. Worsley; K. J. Friston

1995-01-01

109

The suprachiasmatic nucleus and the circadian time-keeping system revisited.  

PubMed

Many physiological and behavioral processes show circadian rhythms which are generated by an internal time-keeping system, the biological clock. In rodents, evidence from a variety of studies has shown the suprachiasmatic nucleus (SCN) to be the site of the master pacemaker controlling circadian rhythms. The clock of the SCN oscillates with a near 24-h period but is entrained to solar day/night rhythm by light. Much progress has been made recently in understanding the mechanisms of the circadian system of the SCN, its inputs for entrainment and its outputs for transfer of the rhythm to the rest of the brain. The present review summarizes these new developments concerning the properties of the SCN and the mechanisms of circadian time-keeping. First, we will summarize data concerning the anatomical and physiological organization of the SCN, including the roles of SCN neuropeptide/neurotransmitter systems, and our current knowledge of SCN input and output pathways. Second, we will discuss SCN transplantation studies and how they have contributed to knowledge of the intrinsic properties of the SCN, communication between the SCN and its targets, and age-related changes in the circadian system. Third, recent findings concerning the genes and molecules involved in the intrinsic pacemaker mechanisms of insect and mammalian clocks will be reviewed. Finally, we will discuss exciting new possibilities concerning the use of viral vector-mediated gene transfer as an approach to investigate mechanisms of circadian time-keeping. PMID:10967353

van Esseveldt, K E; Lehman, M N; Boer, G J

2000-08-01

110

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

NASA Astrophysics Data System (ADS)

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 ? line is discussed.

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

2010-10-01

111

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

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

112

Late-time tails of a self-gravitating massless scalar field, revisited  

E-print Network

We discuss the nonlinear origin of the power-law tail in the long-time evolution of a spherically symmetric self-gravitating massless scalar field in even-dimensional spacetimes. Using third-order perturbation method, we derive explicit expressions for the tail (the decay rate and the amplitude) for solutions starting from small initial data and we verify this prediction via numerical integration of the Einstein-scalar field equations in four and six dimensions. Our results show that the coincidence of decay rates of linear and nonlinear tails in four dimensions (which has misguided some tail hunters in the past) is in a sense accidental and does not hold in higher dimensions.

Piotr Bizo?; Tadeusz Chmaj; Andrzej Rostworowski

2009-08-11

113

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

PubMed

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. PMID:24433472

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

2014-01-01

114

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

SciTech Connect

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.

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

1988-06-16

115

Universality in short-time critical gluodynamics with heat-bath-inspired algorithms  

E-print Network

Short-time dynamics technique is used to study the relaxation process for the (2+1)-dimensional critical gluodynamics of the SU(2) lattice gauge theory. A generalized class of heat-bath-inspired updating algorithms was employed during the short-time regime of the dynamic evolution for performance comparison. The static and dynamic critical exponents of the theory were measured, serving as a dynamic benchmark for algorithmic efficiency. Our results are in agreement with predictions from universality hypothesis and suggest that there is an underlying universal dynamics shared by the analyzed algorithms.

Rafael B. Frigori

2010-04-14

116

Universality in short-time critical gluodynamics with heat-bath-inspired algorithms  

E-print Network

Short-time dynamics technique is used to study the relaxation process for the (2+1)-dimensional critical gluodynamics of the SU(2) lattice gauge theory. A generalized class of heat-bath-inspired updating algorithms was employed during the short-time regime of the dynamic evolution for performance comparison. The static and dynamic critical exponents of the theory were measured, serving as a dynamic benchmark for algorithmic efficiency. Our results are in agreement with predictions from universality hypothesis and suggest that there is an underlying universal dynamics shared by the analyzed algorithms.

Frigori, Rafael B

2010-01-01

117

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

PubMed

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. PMID:23978601

Clark, Daria L; Clark, Robert A

2013-11-01

118

Short collision time approximation for neutron scattering using discrete frequency distributions  

SciTech Connect

A completely general form for computing any scattering cross section based on the incoherent approximation without extending f(..omega..) to negative frequencies and without integrating over the complex plane is presented. A simple derivation of the short collision time approximation for discrete frequency distributions is also given. The approximation works well for large incident neutron energies when the duration of a collision is short compared with the natural periods of atomic motion. Single-differential scattering cross sections for light water as computed with the free proton and Nelkin scattering models at 561/sup 0/K, and the short collision time approximation with T/sub eff/ = 1468/sup 0/K, are shown for an incident neutron energy of 1.0 eV. 1 figure. (RWR)

Ryskamp, J.M.

1980-01-01

119

A ShortTime Scale Colloidal System Reveals Early Bacterial Adhesion Dynamics  

E-print Network

. PLoS Biol 6(7): e167. doi:10. 1371/journal.pbio.0060167 Introduction Bacterial growth on surfacesA Short­Time Scale Colloidal System Reveals Early Bacterial Adhesion Dynamics Christophe Beloin1 important public health and sanitary consequences. However, despite several decades of study of bacterial

120

Capitalists Against Crisis: Employers and Short Time Work in Germany and Italy, 2008-2010  

Microsoft Academic Search

Why did employers pro-actively support the temporary expansion of short time work (STW) schemes during the recent crisis? This paper conceptualizes the role of STW in this contingency as an instrument of subsidized job protection that enabled employers to hoard skilled labor, reduce non-wage labor costs on fallen work hours, and preserve social rest with unions. Two sources of variation

Federico Pancaldi

2011-01-01

121

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...

122

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

E-print Network

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

123

Some Observations on the High-Temperature Short-Time Pasteurization of Chocolate Milk1  

Microsoft Academic Search

The increased use of high-temperature short-time (HTST) pasteurization of whole milk has resulted in a desire by industry to employ this process for other milk products. In plants having a HTST unit it usually would be very desirable from the standpoint of operational efficiency to pasteurize chocolate milk also by this method. Before adopting a process commercially, however, it should

Marvin L. Speck; H. L. Lucas

1951-01-01

124

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

ERIC Educational Resources Information Center

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…

Tsubota, Yoko; Chen, Zhe

2012-01-01

125

Dissociation of Short-Term Forgetting from the Passage of Time  

ERIC Educational Resources Information Center

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…

White, K. Geoffrey

2012-01-01

126

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

E-print Network

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

Dinner, Aaron

127

IEEE SIGNAL PROCESSING LETTERS, VOL. 15, 2008 461 Exploiting Conjugate Symmetry of the Short-Time  

E-print Network

-Time Fourier Spectrum for Speech Enhancement Kamil Wójcicki, Mitar Milacic, Anthony Stark, James Lyons, and Kuldip Paliwal, Member, IEEE Abstract--Typical speech enhancement algorithms operate on the short, speech en- hancement. I. INTRODUCTION IN the field of speech enhancement, we are interested

128

Single-channel speech enhancement using spectral subtraction in the short-time modulation domain  

E-print Network

Single-channel speech enhancement using spectral subtraction in the short-time modulation domain as an alternative to the acoustic domain for speech enhancement. More specif- ically, we wish to determine how. In this study, the effect of modulation frame duration on speech quality of the proposed enhancement method

129

Lay-Offs and Short-Time Working in Selected OECD Countries.  

ERIC Educational Resources Information Center

This report, which includes the conclusions of the Organisation for Economic Cooperation and Development (OECD) Working Party on Employment and Unemployment Statistics, analyzes arrangements for compensating workers in the OECD countries who are temporarily laid-off or subject to short-time work. In introductory sections to part 1, the concepts of…

Grais, Bernard; And Others

130

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...

131

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

Microsoft Academic Search

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

Y. Ephraim; D. Malah

1984-01-01

132

Photoinduced electron transfer and geminate recombination in liquids on short time scales: Experiments and theory  

E-print Network

Photoinduced electron transfer and geminate recombination in liquids on short time scales and geminate recombination between the hole donor Rhodamine 3B and hole acceptors N,N- dimethylaniline recombination back transfer is in the inverted region, and semiclassical treatment developed by Jortner J. Chem

Fayer, Michael D.

133

Filament-Based Atmospheric Dispersion Model to Achieve Short TimeScale Structure of Odor Plumes  

Microsoft Academic Search

This article presents the theoretical motivation, implementation approach, and example validation results for a computationally efficient plume simulation model, designed to replicate both the short-term time signature and long-term exposure statistics of a chemical plume evolving in a turbulent flow. Within the resulting plume, the odor concentration is intermittent with rapidly changing spatial gradient. The model includes a wind field

Jay A. Farrell; John Murlis; Xuezhu Long; Wei Li; Ring T. Cardé

2002-01-01

134

Response Conflict Determines Sequential Effects in Serial Response Time Tasks with Short Response-Stimulus Intervals  

ERIC Educational Resources Information Center

In serial choice reaction time (RT) tasks, performance in each trial critically depends on the sequence of preceding events. In this study, the authors specifically examined the mechanism underlying RT sequence effects at short response-stimulus intervals (RSIs), in which performance is impaired in the current trial N if events alternate rather…

Jentzsch, Ines; Leuthold, Hartmut

2005-01-01

135

Extracting biologically significant patterns from short time series gene expression data  

PubMed Central

Background Time series gene expression data analysis is used widely to study the dynamics of various cell processes. Most of the time series data available today consist of few time points only, thus making the application of standard clustering techniques difficult. Results We developed two new algorithms that are capable of extracting biological patterns from short time point series gene expression data. The two algorithms, ASTRO and MiMeSR, are inspired by the rank order preserving framework and the minimum mean squared residue approach, respectively. However, ASTRO and MiMeSR differ from previous approaches in that they take advantage of the relatively few number of time points in order to reduce the problem from NP-hard to linear. Tested on well-defined short time expression data, we found that our approaches are robust to noise, as well as to random patterns, and that they can correctly detect the temporal expression profile of relevant functional categories. Evaluation of our methods was performed using Gene Ontology (GO) annotations and chromatin immunoprecipitation (ChIP-chip) data. Conclusion Our approaches generally outperform both standard clustering algorithms and algorithms designed specifically for clustering of short time series gene expression data. Both algorithms are available at . PMID:19695084

Tchagang, Alain B; Bui, Kevin V; McGinnis, Thomas; Benos, Panayiotis V

2009-01-01

136

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

E-print Network

Adaptive Filters Revisited :Adaptive Filters Revisited : RFI Mitigation in PulsarRFI Mitigation in Pulsar ObservationsObservations M.Kesteven1, G.Hobbs1, R.Clement2,, B.Dawson1, R.Manchester1 , T.Uppal1/folding. We have started to quantify the RFI impact on the pulsar observations and timing. We continue

Ellingson, Steven W.

137

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

E-print Network

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

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

2006-06-27

138

Currents in complex polymers: An example of superstatistics for short time series  

NASA Astrophysics Data System (ADS)

We apply superstatistical techniques to an experimental time series of measured transient currents through a thin aluminium-PMMA-aluminium film. We show that in good approximation the current can be approximated by local Gaussian processes with fluctuating variance. The marginal density exhibits ‘fat tails’ and is well modelled by a superstatistical model. Our techniques can be generally applied to other short time series as well.

Yalcin, G. Cigdem; Beck, Christian

2012-07-01

139

Time-resolved measurement of photon states using two-photon interference with photons from short-time reference pulses  

E-print Network

To fully utilize the energy-time degree of freedom of photons for optical quantum information processes, it is necessary to control and characterize the quantum states of the photons at extremely short time scales. For measurements 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 reference photon. 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.

Changliang Ren; Holger F. Hofmann

2011-06-01

140

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

NASA Technical Reports Server (NTRS)

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.

Rosenberger, F.

1993-01-01

141

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 52, NO. 1, JANUARY 2014 679 Revisiting the Short-Wave Spectrum of the  

E-print Network

the Short-Wave Spectrum of the Sea Surface in the Light of the Weighted Curvature Approximation Alexandra for the short-wave spectrum of the sea surface are not consistent with microwave satellite data when multi-wave omnidirec- tional spectrum of the sea surface on the basis of a three-band (C, Ku, and Ka) and multi

142

Reframing in dentistry: revisited.  

PubMed

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

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

2013-01-01

143

Novel approach for a precise determination of short-time intervals in ankle sprain experiments.  

PubMed

The etiology of ankle sprain injury is still under debate. Therefore, diagnoses of ankle inversion experiments play an important role. Recent studies stress the importance of exact time measurements due to the short inversion period of around 70ms. This paper presents a novel approach using the vertical ground reaction force (vGRF) to determine the short-time intervals in ankle sprain experiments, which are present in the form of short periods from the beginning of the movement to its end and short latencies to following signals, e.g. EMG onset of peroneal muscles. We compare our method to electrogoniometry at the ankle which is considered as the gold standard. During the inversion movement the kinematic action at the ankle can be measured with electrogoniometry, whereas the vGRF quantifies the vertical dynamic reaction of the tested subject entirely. We observe a difference of DeltaT(f,0-->g,0)=10+/-0.5ms between the first observable vGRF response and the first observable electrogoniometer response following platform release. The end of the ankle inversion measured with electrogoniometry is DeltaT(f,1-->g,1)=3+/-0.5ms later than the maximal vGRF peak. The potential supplementary (mechanical) information of this novel approach compared to electrogoniometry and its ease of use, may be not only interesting for researchers when studying ankle sprain simulations but also for clinicians when testing functional ankle stability. PMID:19766223

Schmitt, Syn; Melnyk, Mark; Alt, Wilfried; Gollhofer, Albert

2009-12-11

144

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

PubMed Central

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

Daehler, Curtis C.

2009-01-01

145

Motor skill acquisition across short and long time scales: a meta-analysis of neuroimaging data.  

PubMed

In this systematic review and meta-analysis, we explore how the time scale of practice affects patterns of brain activity associated with motor skill acquisition. Fifty-eight studies that involved skill learning with healthy participants (117 contrasts) met inclusion criteria. Two meta-contrasts were coded: decreases: peak coordinates that showed decreases in brain activity over time; increases: peak coordinates that showed increases in activity over time. Studies were grouped by practice time scale: short (?1 h; 25 studies), medium (>1 and ?24 h; 18 studies), and long (>24h to 5 weeks; 17 studies). Coordinates were analyzed using Activation Likelihood Estimation to show brain areas that were consistently activated for each contrast. Across time scales, consistent decreases in activity were shown in prefrontal and premotor cortex, the inferior parietal lobules, and the cerebellar cortex. Across the short and medium time scales there were consistent increases in supplementary and primary motor cortex and dentate nucleus. At the long time scale, increases were seen in posterior cingulate gyrus, primary motor cortex, putamen, and globus pallidus. Comparisons between time scales showed that increased activity in M1 at medium time scales was more spatially consistent across studies than increased activity in M1 at long time scales. Further, activity in the striatum (viz. putamen and globus pallidus) was consistently more rostral in the medium time scale and consistently more caudal in the long time scale. These data support neurophysiological models that posit that both a cortico-cerebellar system and a cortico-striatal system are active, but at different time points, during motor learning, and suggest there are associative/premotor and sensorimotor networks active within each system. PMID:24831923

Lohse, K R; Wadden, K; Boyd, L A; Hodges, N J

2014-07-01

146

Short-time motion of Brownian particles in a shear flow  

NASA Astrophysics Data System (ADS)

The short-time motion of Brownian particles in an incompressible Newtonian fluid under shear, in which the fluid inertia becomes important, was investigated by direct numerical simulation of particulate flows. Three-dimensional simulations were performed, wherein external forces were introduced to approximately form Couette flows throughout the entire system with periodic boundary conditions. In order to examine the validity of the method, the mean-square displacement of a single spherical particle in a simple shear flow was calculated, and these results were compared with a hydrodynamic analytical solution that includes the effects of the fluid inertia. Finally, the dynamical behavior of a monodisperse dispersion composed of repulsive spherical particles was examined on short-time scales, and the shear-induced diffusion coefficients were measured for several volume fractions up to 0.50.

Iwashita, Takuya; Yamamoto, Ryoichi

2009-03-01

147

Short-time dynamics at a conical intersection in high-harmonic spectroscopy.  

PubMed

High-harmonic spectroscopy probes molecular dynamics using electrons liberated from the same molecule earlier in the laser cycle. It affords sub-Ångstrom spatial and subfemtosecond temporal resolution. Nuclear dynamics in the intermediate cation influence the spectrum of the emitted high-harmonic photons through an autocorrelation function. Here, we develop an analytical approach for computing short-time nuclear autocorrelation functions in the vicinity of conical intersections, including laser-induced and nonadiabatic coupling between the surfaces. We apply the technique to two molecules of current experimental interest, C6H6 and C6H5F. In both molecules, high-harmonics generated within the same electronic channel are not sensitive to nonadiabatic dynamics, even in the presence of substantial population transfer. Calculated autocorrelation functions exhibit significant deviations from the expected Gaussian decay and may undergo revivals at short (?1.5 fs) times. The associated phase of the nuclear wavepacket provides a possible experimental signature. PMID:25314638

Patchkovskii, Serguei; Schuurman, Michael S

2014-12-26

148

Economic History Revisited: New Uncertainties  

E-print Network

Economic History Revisited: New Uncertainties I n the last Sitar-Rutgers Regional Report, we the fourth straight year of improvement, it was nowhere near "breakout" status. For the first time in six years, the state's job growth fell behind that of the nation. A brief discussion of rebenchmarking

149

The short-time limit of the Dirichlet partition function and the image method  

E-print Network

In this paper we calculate the short-time limit of the free partition function for a diffusion process on tessellations of the n-dimensional Euclidean space $\\mathbb{E}^n, \\, n=1,2,3$ with an absorbing boundary. Utilising the method of images for domains which are compatible with finite reflection subgroups of the orthogonal group $\\mathbb{O}_n$ we recover old results from a different viewpoint and produce new ones.

Agapitos Hatzinikitas

2014-10-07

150

Influence of Ramadan fasting on anaerobic performance and recovery following short time high intensity exercise  

Microsoft Academic Search

The aim of this study was to investigate the effects of Ramadan fasting on anaerobic power and capacity and the removal rate of lactate after short time high intensity exercise in power athletes. Ten male elite power athletes (2 wrestlers, 7 sprinters and 1 thrower, aged 20-24 yr, mean age 22.30 ± 1.25 yr) participated in this study. The subjects

Umid Karli; Alpay Guvenc; Alper Aslan; Tahir Hazir

151

INVESTIGATIONS IN THE STRENGTH OF GLULAM MULTILAYERED BEAMS UNDER A SHORT-TIME SHEAR  

Microsoft Academic Search

The author of the article has performed wide-range tests of glulam beams. The objective of the tests is increasing of load bearing capacity of such beams under shear. As a result 5 inventions have been suggested and confirmed. In total 44 beams of various types were tested under the action of short and long-time loadings.These investigations have verified a new

R. ?echavi?ius

1998-01-01

152

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

Microsoft Academic Search

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

E. Toth; A. Brath; A. Montanari

2000-01-01

153

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

154

Long-Time Protein Folding Dynamics from Short-Time Molecular Dynamics Simulations  

Microsoft Academic Search

Protein folding involves physical timescales—microseconds to seconds—that are too long to be studied directly by straightforward molecular dynamics simulation, where the fundamental timestep is constrained to femtoseconds. Here we show how the long-time statistical dynamics of a simple solvated biomolecular system can be well described by a discrete-state Markov chain model constructed from trajectories that are an order of magnitude

John D. Chodera; William C. Swope; Jed W. Pitera; Ken A. Dill

2006-01-01

155

Intermittency, current flows, and short time diffusion in interacting finite sized one-dimensional fluids  

NASA Astrophysics Data System (ADS)

Long time molecular dynamics simulations of one-dimensional Lennard-Jones systems reveal that while the diffusion coefficient of a tagged particle indeed goes to zero in the very long time, the mean-square displacement is linear with time at short to intermediate times, allowing the definition of a short time diffusion coefficient [Lebowitz and Percus, Phys. Rev. 155, 122 (1967)]. The particle trajectories show intermittent displacements, surprisingly similar to the recent experimental results [Wei et al., Science 287, 625 (2000)]. A self-consistent mode coupling theory is presented which can partly explain the rich dynamical behavior of the velocity correlation function and also of the frequency dependent friction. The simulations show a strong dependence of the velocity correlation function on the size of the system, quite unique to one dimensional interacting systems. Inclusion of background noise leads to a dramatic change in the profile of the velocity time correlation function, in agreement with the predictions of Percus [Phys. Rev. A 9, 557 (1974)].

Pal, Subrata; Srinivas, Goundla; Bhattacharyya, Sarika; Bagchi, Biman

2002-04-01

156

Dissociation of short-term forgetting from the passage of time.  

PubMed

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 retention interval. Recall accuracy at long retention intervals recovered from the level consistent with the hard interfering task to a more accurate level consistent with an easy interfering task. Such recovery is not in agreement with theories that link forgetting to the passage of time, such as trace decay. The reversed forgetting functions are more consistent with an account in which different levels of nonspecific retroactive interference in the retention interval just before the time of retrieval influence different levels of performance accuracy. With the uncoupling of interference levels from time, forgetting is dissociated from the passage of time. PMID:21875248

White, K Geoffrey

2012-01-01

157

Relaxation time mapping of short T*2 nuclei with single-point imaging (SPI) methods.  

PubMed

New techniques for quantitative mapping of T1, T2, and T*2 are proposed, based on the single-point imaging (SPI) method, for materials with short nuclear magnetic resonance relaxation times which cannot be imaged with traditional methods. Relaxation times extracted from two-dimensional images of uniform doped agarose phantoms (T*2 approximately 60-210 microseconds) as well as hardened mortar (T*2 approximately 220 microseconds) and polymers (T*2 approximately 20-100 microseconds), using these techniques, agreed with bulk measurements. The method was then applied to a partially dried cylindrical concrete sample (T*2 approximately 115 microseconds). PMID:9799689

Beyea, S D; Balcom, B J; Prado, P J; Cross, A R; Kennedy, C B; Armstrong, R L; Bremner, T W

1998-11-01

158

Relaxation Time Mapping of Short T*2Nuclei with Single-Point Imaging (SPI) Methods  

NASA Astrophysics Data System (ADS)

New techniques for quantitative mapping ofT1,T2, andT*2are proposed, based on thesingle-pointimaging (SPI) method, for materials with short nuclear magnetic resonance relaxation times which cannot be imaged with traditional methods. Relaxation times extracted from two-dimensional images of uniform doped agarose phantoms (T*2? 60-210 ?s) as well as hardened mortar (T*2? 220 ?s) and polymers (T*2? 20-100 ?s), using these techniques, agreed with bulk measurements. The method was then applied to a partially dried cylindrical concrete sample (T*2? 115 ?s).

Beyea, Steven D.; Balcom, Bruce J.; Prado, Pablo J.; Cross, Albert R.; Kennedy, Christopher B.; Armstrong, Robin L.; Bremner, Theodore W.

1998-11-01

159

Development of the short time exposure (STE) test: An in vitro eye irritation test using SIRC cells  

Microsoft Academic Search

Using SIRC (rabbit corneal cell line) cells, we developed an alternative eye irritation test: the short time exposure (STE) test. This STE test is a cytotoxicity test using physiological saline or mineral oil as the test solvent. Evaluation exposure time is short (5min), which is similar to actual exposure situations, and uses the cell viability (CV) at a constant concentration

Yutaka Takahashi; Mirei Koike; Hiroshi Honda; Yuichi Ito; Hitoshi Sakaguchi; Hiroyuki Suzuki; Naohiro Nishiyama

2008-01-01

160

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

E-print Network

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

161

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

PubMed

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

Tomasula, P M; Kozempel, M F

2004-09-01

162

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

PubMed

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. PMID:22196346

Koivula, Hanna; Toivakka, Martti; Gane, Patrick

2012-03-01

163

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

PubMed Central

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

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

2015-01-01

164

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

NASA Technical Reports Server (NTRS)

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.

Emslie, A. G.

1983-01-01

165

Short-time behavior of advecting-diffusing scalar fields in Stokes flows.  

PubMed

This article addresses the short-term decay of advecting-diffusing scalar fields in Stokes flows. The analysis is developed in two main subparts. In the first part, we present an analytic approach for a class of simple flow systems expressed mathematically by the one-dimensional advection-diffusion equation w(y)?(?)?=??(y)(2)?+iV(y)?-?'?, where ? is either time or axial coordinate and iV(y) an imaginary potential. This class of systems encompasses both open- and closed-flow models and corresponds to the dynamics of a single Fourier mode in parallel flows. We derive an analytic expression for the short-time (short-length) decay of ?, and show that this decay is characterized by a universal behavior that depends solely on the singularity of the ratio of the transverse-to-axial velocity components V(eff)(y)=V(y)/w(y), corresponding to the effective potential in the imaginary potential formulation. If V(eff)(y) is smooth, then ||?||(L(2))(?)=exp(-?'?-b?(3)), where b>0 is a constant. Conversely, if the effective potential is singular, then ||?||(L(2))(?)=1-a?(?) with a>0. The exponent ? attains the value 5/3 at the very early stages of the process, while for intermediate stages its value is 3/5. By summing over all of the Fourier modes, a stretched exponential decay is obtained in the presence of nonimpulsive initial conditions, while impulsive conditions give rise to an early-stage power-law behavior. In the second part, we consider generic, chaotic, and nonchaotic autonomous Stokes flows, providing a kinematic interpretation of the results found in the first part. The kinematic approach grounded on the warped-time transformation complements the analytical theory developed in the first part. PMID:23848776

Giona, M; Anderson, P D; Garofalo, F

2013-06-01

166

Noninvasive assessment of arterial compliance of human cerebral arteries with short inversion time arterial spin labeling  

PubMed Central

A noninvasive method of assessing cerebral arterial compliance (AC) is introduced in which arterial spin labeling (ASL) is used to measure changes in arterial blood volume (aBV) occurring within the cardiac cycle. Short inversion time pulsed ASL (PASL) was performed in healthy volunteers with inversion times ranging from 250 to 850?ms. A model of the arterial input function was used to obtain the cerebral aBV. Results indicate that aBV depends on the cardiac phase of the arteries in the imaging volume. Cerebral AC, estimated from aBV and brachial blood pressure measured noninvasively in systole and diastole, was assessed in the flow territories of the basal cerebral arteries originating from the circle of Willis: right and left middle cerebral arteries (RMCA and LMCA), right and left posterior cerebral arteries (RPCA and LPCA), and the anterior cerebral artery (ACA). Group average AC values calculated for the RMCA, LMCA, ACA, RPCA, and LPCA were 0.56%±0.2%, 0.50%±0.3%, 0.4%±0.2%, 1.1%±0.5%, and 1.1%±0.3% per mm?Hg, respectively. The current experiment has shown the feasibility of measuring AC of cerebral arteries with short inversion time PASL. PMID:25515216

Warnert, Esther AH; Murphy, Kevin; Hall, Judith E; Wise, Richard G

2015-01-01

167

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

PubMed

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. PMID:9361200

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

1997-10-01

168

Short-Time Operator Product Expansion for rf Spectroscopy of a Strongly Interacting Fermi Gas  

SciTech Connect

Universal relations that hold for any state provide powerful constraints on systems consisting of fermions with two spin states interacting with a large scattering length. In radio-frequency (rf) spectroscopy, the mean shift in the rf frequency and the large-frequency tail of the rf transition rate are proportional to the contact, which measures the density of pairs with small separations. We show that these universal relations can be derived and extended by using the short-time operator product expansion of quantum field theory. This is a general method for identifying aspects of many-body physics that are controlled by few-body physics.

Braaten, Eric; Kang, Daekyoung [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); Platter, Lucas [Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195 (United States)

2010-06-04

169

Scaling and short-time corrections for random walks on two-dimensional exactly percolating clusters  

NASA Astrophysics Data System (ADS)

Random-walk simulations on square-lattice percolation clusters are performed for (a) all clusters at criticality; (b) the largest cluster at nominal criticality; and (c) the largest cluster at exact criticality for each realization (new method). The short-time correction-to-scaling exponent is obtained: ?=-0.48 (for N<103 Monte Carlo steps). The scaling exponent appears to be in better agreement with the recent Aharony-Stauffer conjecture for the spectral dimension (ds=1.309) than with the Alexander-Orbach-Rammal-Toulouse conjecture (ds=1.333).

Keramiotis, Artemios; Argyrakis, Panos; Kopelman, Raoul

1985-04-01

170

Investigation of Short-Time Heat Transfer Effects by an Optical Pump–Probe Method  

Microsoft Academic Search

The study of heat transfer properties on micro- and nanoscales generally requires one to work on time scales ranging between\\u000a a few picoseconds and a few nanoseconds, whether one is concerned with diffusion over short length scales or heat exchanges\\u000a involving small volumes of matter. Optical methods are particularly well-suited to the study of small systems for various\\u000a reasons:\\u000a \\u000a \\u000a \\u000a \\u000a • 

Bernard Perrin

171

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

NASA Astrophysics Data System (ADS)

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 10-6 Torr to 102 Torr, 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.

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

2014-07-01

172

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

SciTech Connect

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{sup ?6?}Torr to 10{sup 2?}Torr, the plume intensity is found to increase rapidly as the pressure crosses 1?Torr. Time of flight (TOF) spectroscopy of emission from neutral nickel (Ni I) at 361.9?nm (3d{sup 9}({sup 2}D) 4p ? 3d{sup 9}({sup 2}D) 4s transition) reveals two peaks (fast and slow species) in short-pulse excitation and a single peak in ultrafast excitation. The fast and slow peaks represent recombined neutrals and un-ionized neutrals, respectively. TOF emission from singly ionized nickel (Ni II) studied using the 428.5?nm (3p{sup 6}3d{sup 8}({sup 3}P) 4s? 3p{sup 6}3d{sup 9} 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.

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

2014-07-07

173

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

PubMed Central

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

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

2013-01-01

174

Short time-step performances of coaxial and double U-tube borehole heat exchangers: Modeling and measurements  

Microsoft Academic Search

Several authors have investigated the long time-step performance of borehole heat exchangers. In that time scale, the borehole thermal capacitance is generally neglected, since the time span of interest is on the order of months or years. The borehole thermal capacitance consists both of grouting material and heat carrier fluid, and it mostly affects the short time-step behavior, when hourly

Angelo Zarrella; Massimiliano Scarpa; Michele De Carli

2011-01-01

175

Short restraint time does not influence markers of serum oxidative stress in homing pigeons (Columba livia).  

PubMed

Restraint in a confined space, such as a cage or a box, may be perceived by birds as a stressful condition. Some concern has been expressed about restraining homing pigeons (Columba livia) in transport crates for sport or for scientific research. Therefore, this study sought to test whether short restraint time in a transport crate for 1, 2 or 18 (overnight) h causes oxidative stress in homing pigeons and whether it is more stressful than flying. To isolate the effect of crowding from that of transport per se, the pigeons were kept in an immobile crate, that is, without any movement. To quantify oxidative stress, we measured serum levels of oxidative damage (ROMs) and of antioxidant capacity (OXY). We found that pigeons restrained in transport crates showed no significant variation for both markers of oxidative stress, regardless of the duration of restraint. Conversely, pigeons which had flown around 200 km had increased levels of oxidative damage and decreased levels of serum OXY, both clear manifestations of oxidative stress. These results suggest that maintaining homing pigeons in transport crates for a short time (i.e. 1-18 h) does not cause oxidative stress. PMID:19138344

Costantini, D; Lipp, H-P

2010-02-01

176

Short-time dynamics of Fe{sub 2}/V{sub 13} magnetic superlattice models  

SciTech Connect

Critical relaxation from a low-temperature fully ordered state of Fe{sub 2}/V{sub 13} iron-vanadium magnetic superlattice models has been studied using the method of short-time dynamics. Systems with three variants of the ratio R of inter-to intralayer exchange coupling have been considered. Particles with N = 262144 spins have been simulated with periodic boundary conditions. Calculations have been performed using the standard Metropolis algorithm of the Monte Carlo method. The static critical exponents of magnetization and correlation radius, as well as the dynamic critical exponent, have been calculated for three R values. It is established that a small decrease in the exchange ratio (from R = 1.0 to 0.8) does not significantly influence the character of the short-time dynamics in the models studied. A further significant decrease in this ratio (to R = 0.01), for which a transition from three-dimensional to quasi-two-dimensional magnetism is possible, leads to significant changes in the dynamic behavior of iron-vanadium magnetic superlattice models.

Murtazaev, A. K.; Mutailamov, V. A., E-mail: vadim.mut@mail.ru [Russian Academy of Sciences, Amirkhanov Institute of Physics, Daghestan Scientific Center (Russian Federation)

2013-04-15

177

Short-time critical dynamics of damage spreading in the two-dimensional Ising model.  

PubMed

The short-time critical dynamics of propagation of damage in the Ising ferromagnet in two dimensions is studied by means of Monte Carlo simulations. Starting with equilibrium configurations at T=? and magnetization M=0 , an initial damage is created by flipping a small amount of spins in one of the two replicas studied. In this way, the initial damage is proportional to the initial magnetization M0 in one of the configurations upon quenching the system at T C, the Onsager critical temperature of the ferromagnetic-paramagnetic transition. It is found that, at short times, the damage increases with an exponent ? D=1.915(3) , which is much larger than the exponent ?=0.197 characteristic of the initial increase of the magnetization M(t). Also, an epidemic study was performed. It is found that the average distance from the origin of the epidemic (R2(t)) grows with an exponent z? ? ? ? 1.9, which is the same, within error bars, as the exponent ? D. However, the survival probability of the epidemics reaches a plateau so that ?=0. On the other hand, by quenching the system to lower temperatures one observes the critical spreading of the damage at T D ? 0.51TC, where all the measured observables exhibit power laws with exponents ? D=1.026(3), ?=0.133(1), and z?=1.74(3). PMID:20866194

Puzzo, M Leticia Rubio; Albano, Ezequiel V

2010-05-01

178

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

NASA Astrophysics Data System (ADS)

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

Wang, Mu; Brady, John F.

2015-03-01

179

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

PubMed

We present a comprehensive computational study of the short-time transport properties of bidisperse hard-sphere colloidal suspensions and the corresponding porous media. Our study covers bidisperse particle size ratios up to 4 and total volume fractions up to and beyond the monodisperse hard-sphere close packing limit. The many-body hydrodynamic interactions are computed using conventional Stokesian Dynamics (SD) via a Monte-Carlo approach. We address suspension properties including the short-time translational and rotational self-diffusivities, the instantaneous sedimentation velocity, the wavenumber-dependent partial hydrodynamic functions, and the high-frequency shear and bulk viscosities and porous media properties including the permeability and the translational and rotational hindered diffusivities. We carefully compare the SD computations with existing theoretical and numerical results. For suspensions, we also explore the range of validity of various approximation schemes, notably the pairwise additive approximations with the Percus-Yevick structural input. We critically assess the strengths and weaknesses of the SD algorithm for various transport properties. For very dense systems, we discuss in detail the interplay between the hydrodynamic interactions and the structures due to the presence of a second species of a different size. PMID:25747100

Wang, Mu; Brady, John F

2015-03-01

180

Short-time transport properties of bidisperse suspensions and porous media: a Stokesian Dynamics study  

E-print Network

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

Mu Wang; John F. Brady

2014-12-28

181

Minimization of acquisition time in short-range free-space optical communication.  

PubMed

We consider short-range (1-3-km) free-space optical communication between moving parties when covertness is the overriding system performance requirement. To maximize covertness, it is critical to minimize the time required for the acquisition phase, during which the party initiating contact must conduct a broad-field scan and so risks revealing his position. Assuming an elliptical Gaussian beam profile, we show how to optimize the beam divergence angles, scan speed, and design of the raster scan pattern so as to minimize acquisition time. In this optimization, several constraints are considered, including signal-to-noise ratio, required for accurate bearing detection and reliable decoding; limited receiver bandwidth; limited scanner speed; and beam divergence as limited by the scanner mirror dimensions. The effects of atmospheric turbulence are also discussed. PMID:12510925

Wang, Jin; Kahn, Joseph M; Lau, Kam Y

2002-12-20

182

Measurement and deconvolution of detector response time for short HPM pulses: Part 1, Microwave diodes  

SciTech Connect

A technique is described for measuring and deconvolving response times of microwave diode detection systems in order to generate corrected input signals typical of an infinite detection rate. The method has been applied to cases of 2.86 GHz ultra-short HPM pulse detection where pulse rise time is comparable to that of the detector; whereas, the duration of a few nanoseconds is significantly longer. Results are specified in terms of the enhancement of equivalent deconvolved input voltages for given observed voltages. The convolution integral imposes the constraint of linear detector response to input power levels. This is physically equivalent to the conservation of integrated pulse energy in the deconvolution process. The applicable dynamic range of a microwave diode is therefore limited to a smaller signal region as determined by its calibration.

Bolton, P.R.

1987-06-01

183

Effects of time-gated detection in diffuse optical imaging at short source-detector separation  

NASA Astrophysics Data System (ADS)

The adoption of a short source-detector distance, combined with a time-resolved acquisition, can be advantageous in diffuse optical imaging due to the stricter spatial localization of the probing photons, provided that the strong burst of early photons is suppressed using a time-gated detection scheme. We propose a model for predicting the effect of the time-gated measurement system using a time-variant operator built on the system response acquired at different gate delays. The discrete representation of the system operator, termed Spread Matrix, can be analyzed to identify the bottlenecks of the detection system with respect to the physical problem under study. Measurements performed on tissue phantoms, using a time-gated single-photon avalanche diode and an interfiber distance of 2 mm, demonstrate that inhomogeneities down to 3 cm can be detected only if the decay constant of the detector is lower than 100 ps, while the transient opening of the gate has a less critical impact.

Contini, Davide; Dalla Mora, Alberto; Spinelli, Lorenzo; Farina, Andrea; Torricelli, Alessandro; Cubeddu, Rinaldo; Martelli, Fabrizio; Zaccanti, Giovanni; Tosi, Alberto; Boso, Gianluca; Zappa, Franco; Pifferi, Antonio

2015-02-01

184

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

E-print Network

Recently a method which employs computing of fluctuations in a measure of nonlinear similarity based on local recurrence properties in a univariate time series, was introduced to identify distinct dynamical regimes and transitions between them in a short time series [1]. Here we present the details of the analytical relationships between the 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 employ it to identify various types of dynamical transitions in different nonlinear models. Also, we present testbed examples for the new method's robustness against the presence of noise and missing values in the time series. Furthermore, we use this method to analyze time series from the field of social dynamics, where we present an analysis of the US crime record's time series from the year 1975 to 1993. Using this method, we have found that dynamical complexity in robberies was influenced by the unemployment rate till 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.

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

2013-10-30

185

Improvements in Solar Adaptive Optics Correction using Short-time Turbulence Forecasting  

NASA Astrophysics Data System (ADS)

Time delay error and integration time effects play a crucial role in Solar Adaptive Optics systems. By using a multi-layer turbulence simulation we studied temporal variations of atmospheric turbulence. We simulated Shack-Hartmann wavefront sensing with Zernike and Kharunen-Loeve modal expansions too. These two sets of polynomial basis have been defined over an annular pupil with a large central obscurament, which is a common feature in Ritchey-Chretien optical configuration. We found that Karhunen-Loeve functions, defined using principal component analisys methods as a linear combination of Zernike modes, represent the best choice for wavefront reconstruction, giving us the possibility of reducing fitting error with respect to Zernike modal expansion. Finally, we tested the possibility to use auto-regressive moving average time series models to provide short time forecasting for Zernike or Karhunen-Loeve coefficients. This scheme may be very helpful in improving correction bandwidth and overcoming time delay errors in next generation solar Adaptive Optics systems. These preliminary results could be particularly important in developing and studying design and performance for next European Solar Telescope.

Stangalini, M.; Del Moro, D.; Berrilli, F.

2008-09-01

186

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

SciTech Connect

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.

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

187

Fossil turbulence revisited  

E-print Network

A theory of fossil turbulence presented in the 11th Liege Colloquium on Marine turbulence is "revisited" in the 29th Liege Colloquium "Marine Turbulence Revisited". The Gibson (1980) theory applied universal similarity theories of turbulence and turbulent mixing to the vertical evolution of an isolated patch of turbulence in a stratified fluid as it is constrained and fossilized by buoyancy forces. Towed oceanic microstructure measurements of Schedvin (1979) confirmed the predicted universal constants. Universal constants, spectra, hydrodynamic phase diagrams (HPDs) and other predictions of the theory have been reconfirmed by a wide variety of field and laboratory observations. Fossil turbulence theory has many applications; for example, in marine biology, laboratory and field measurements suggest phytoplankton species with different swimming abilities adjust their growth strategies differently by pattern recognition of several days of turbulence-fossil-turbulence dissipation and persistence times above threshold values, signaling a developing surface layer sea change. In cosmology, self-gravitational structure masses are interpreted as fossils of primordial hydrodynamic states.

Carl H. Gibson

1999-04-27

188

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

E-print Network

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

Arseni Goussev

2011-05-16

189

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

SciTech Connect

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.

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

2008-09-01

190

Effect of Short-Time Povidone-Iodine Application on Osteoblast Proliferation and Differentiation  

PubMed Central

Background and Objective: Povidone-iodine [polyvinylpyrrolidone-iodine complex (PVP-I)] is a broad-spectrum antimicrobial agent, frequently used in dentistry. In this study we investigated the short- and longterm effects on osteoblast number, viability, and function after short exposure to PVP-I with and without additional bone-morphogenetic protein-2 (BMP-2). Material and Methods: Confluent osteoblast-like cell line (MC3T3-E1, subclone 24) cultures were exposed to pure PVP-I solution (7.7 mg/ml) and dilutions of 1:10, 1:100 and 1:1000 for 10 seconds and washed with phosphate buffer solution. Cell proliferation and viability was determined by MTT and differentiation status by alkaline phosphatase (ALP) activity 6 days after initial plating. In a separate experiment, long-term cell proliferation, viability and function were assessed 4 weeks after PVP-I treatment by MTT and deposited calcium using an Alizarin-red staining test. Results: PVP-I decreased ALP activity substantially. Stimulation by BMP-2 recovered ALP activity to near control levels at 1:100 and 1:1000 dilutions of PVP-I. The MTT assay showed reduced proliferation of the preosteoblastic cells for all treatments, irrespective whether BMP-2 was used or not. Only at PVP-I dilutions of 1:1000 proliferation rate was back to normal levels (95.6±2.4 %). No adverse long-term effect of PVP-I on mineralization of the extracellular matrix (Alizarinred) for dilutions higher than 1:100 was observed. Interestingly, undiluted and 1:10 diluted PVP-I even showed a significant increase in mineral deposition, especially in the presence of BMP-2. Conclusion: Short-time application of PVP-I in concentrations of 1:10 and higher lead to decreased viability and impaired differentiation. However, surviving cells showed good recovery and mineralization potential. PMID:19915721

Schmidlin, P.R; Imfeld, T; Sahrmann, P; Tchouboukov, A; Weber, F.E

2009-01-01

191

Performance of short-time spectral parametric methods for reducing the variance of the Doppler ultrasound mean instantaneous frequency estimation  

Microsoft Academic Search

To achieve an accurate estimation of the instantaneous turbulent velocity fluctuations downstream of prosthetic heart valves\\u000a in vivo, the variability of the spectral method used to measure the mean frequency shift of the Doppler signal (i.e. the Doppler\\u000a velocity) should be minimised. This paper investigates the performance of various short-time spectral parametric methods such\\u000a as the short-time Fourier transform, autoregressive

H. Sava; L.-G. Durand; G. Cloutier

1999-01-01

192

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

PubMed

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. PMID:25019852

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

2014-06-01

193

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

194

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

NASA Technical Reports Server (NTRS)

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.

Amini, Abolfazl M.; Figueroa, Fernando

2004-01-01

195

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

PubMed

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. PMID:23416586

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

2013-01-01

196

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

PubMed Central

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

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

2007-01-01

197

Revisiting Lambert's problem  

NASA Astrophysics Data System (ADS)

The orbital boundary value problem, also known as Lambert problem, is revisited. Building upon Lancaster and Blanchard approach, new relations are revealed and a new variable representing all problem classes, under L-similarity, is used to express the time of flight equation. In the new variable, the time of flight curves have two oblique asymptotes and they mostly appear to be conveniently approximated by piecewise continuous lines. We use and invert such a simple approximation to provide an efficient initial guess to an Householder iterative method that is then able to converge, for the single revolution case, in only two iterations. The resulting algorithm is compared, for single and multiple revolutions, to Gooding's procedure revealing to be numerically as accurate, while having a significantly smaller computational complexity.

Izzo, Dario

2015-01-01

198

Improving misalignment for feedback path estimation in hearing aid by multiple short-time noise injections.  

PubMed

Adaptive Feedback Cancellation (AFC) methods are used to find an FIR filter to cancel the negative effect of acoustic feedback between the loudspeaker and microphone of the hearing aid. Finding the AFC filter of appropriate order/length directly affects the performance and complexity of the system. In this paper, we use noise injection method to find the AFC filter estimating the feedback path model. We show that the optimum length which guarantees a good compromise between the quality and the complexity of the system may be smaller than the length of the actual feedback path model. However, in order to improve the performance of the system in terms of Misalignment criterion, we propose using multiple short-time noise injections and averaging method to find the best filter estimate of appropriate length. PMID:23367108

Khoubrouy, Soudeh A; Panahi, Issa M S

2012-01-01

199

Evolutionary dynamics of Clostridium difficile over short and long time scales.  

PubMed

Clostridium difficile has rapidly emerged as the leading cause of antibiotic-associated diarrheal disease, with the transcontinental spread of various PCR ribotypes, including 001, 017, 027 and 078. However, the genetic basis for the emergence of C. difficile as a human pathogen is unclear. Whole genome sequencing was used to analyze genetic variation and virulence of a diverse collection of thirty C. difficile isolates, to determine both macro and microevolution of the species. Horizontal gene transfer and large-scale recombination of core genes has shaped the C. difficile genome over both short and long time scales. Phylogenetic analysis demonstrates C. difficile is a genetically diverse species, which has evolved within the last 1.1-85 million years. By contrast, the disease-causing isolates have arisen from multiple lineages, suggesting that virulence evolved independently in the highly epidemic lineages. PMID:20368420

He, Miao; Sebaihia, Mohammed; Lawley, Trevor D; Stabler, Richard A; Dawson, Lisa F; Martin, Melissa J; Holt, Kathryn E; Seth-Smith, Helena M B; Quail, Michael A; Rance, Richard; Brooks, Karen; Churcher, Carol; Harris, David; Bentley, Stephen D; Burrows, Christine; Clark, Louise; Corton, Craig; Murray, Vicky; Rose, Graham; Thurston, Scott; van Tonder, Andries; Walker, Danielle; Wren, Brendan W; Dougan, Gordon; Parkhill, Julian

2010-04-20

200

Evolutionary dynamics of Clostridium difficile over short and long time scales  

PubMed Central

Clostridium difficile has rapidly emerged as the leading cause of antibiotic-associated diarrheal disease, with the transcontinental spread of various PCR ribotypes, including 001, 017, 027 and 078. However, the genetic basis for the emergence of C. difficile as a human pathogen is unclear. Whole genome sequencing was used to analyze genetic variation and virulence of a diverse collection of thirty C. difficile isolates, to determine both macro and microevolution of the species. Horizontal gene transfer and large-scale recombination of core genes has shaped the C. difficile genome over both short and long time scales. Phylogenetic analysis demonstrates C. difficile is a genetically diverse species, which has evolved within the last 1.1–85 million years. By contrast, the disease-causing isolates have arisen from multiple lineages, suggesting that virulence evolved independently in the highly epidemic lineages. PMID:20368420

He, Miao; Sebaihia, Mohammed; Lawley, Trevor D.; Stabler, Richard A.; Dawson, Lisa F.; Martin, Melissa J.; Holt, Kathryn E.; Seth-Smith, Helena M.B.; Quail, Michael A.; Rance, Richard; Brooks, Karen; Churcher, Carol; Harris, David; Bentley, Stephen D.; Burrows, Christine; Clark, Louise; Corton, Craig; Murray, Vicky; Rose, Graham; Thurston, Scott; van Tonder, Andries; Walker, Danielle; Wren, Brendan W.; Dougan, Gordon; Parkhill, Julian

2010-01-01

201

Short-time particulate matter PM10 forecasts using predictive modeling techniques  

NASA Astrophysics Data System (ADS)

Two types of predictive modeling techniques - seasonal autoregressive integrated moving average (SARIMA) and a new Generalized PathSeeker (GPS) Regularized Regression method have been used for modeling data related to ambient air quality. The models are built for the measured data for the primary air pollutant - particulate matter PM10 in the town of Shumen, Bulgaria. The time series analysis was carried out based on hourly data with respect to six meteorological variables during a period of one month. The constructed models have been used for short-term four-days-ahead forecasts. The obtained results demonstrate some advantages of the GPS method over seasonal ARIMA stochastic modeling and its applicability. This gives a new perspective for analyzing and preventing the possible pollution problems in urban areas.

Ivanov, A.; Gocheva-Ilieva, S.

2013-10-01

202

Diagnosis of brain tumors using dynamic contrast-enhanced perfusion imaging with a short acquisition time.  

PubMed

This study sought to determine the diagnostic utility of perfusion parameters derived from dynamic contrast-enhanced (DCE) perfusion MRI with a short acquisition time (approximately 3.5 min) in patients with glioma, brain metastasis, and primary CNS lymphoma (PCNSL). Twenty-six patients with 29 lesions (4 low-grade glioma, 13 high-grade glioma, 7 metastasis, and 5 PCNSL) underwent DCE-MRI in a 3 T scanner. A ROI was placed on the hotspot of each tumor in maps for volume transfer contrast K (trans) , extravascular extracellular volume V e , and fractional plasma volume V p . We analyzed differences in parameters between tumors using the Mann-Whitney U test. We calculated sensitivity and specificity using receiver operating characteristics analysis. Mean K (trans) values of LGG, HGG, metastasis and PCNSL were 0.034, 0.31, 0.38, 0.44, respectively. Mean Ve values of each tumors was 0.036, 0.57, 0.47, 0.96, and mean Vp value of each tumors was 0.070, 0.086, 0.26, 0.17, respectively. Compared with other tumor types, low-grade glioma showed lower K (trans) (P?short acquisition time provide useful information for the differential diagnosis of brain tumors. PMID:25793147

Abe, Takashi; Mizobuchi, Yoshifumi; Nakajima, Kohei; Otomi, Yoichi; Irahara, Saho; Obama, Yuki; Majigsuren, Mungunkhuyag; Khashbat, Delgerdalai; Kageji, Teruyoshi; Nagahiro, Shinji; Harada, Masafumi

2015-01-01

203

Short Dissipation Times of Proto-planetary Disks: An Artifact of Selection Effects?  

NASA Astrophysics Data System (ADS)

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.

Pfalzner, Susanne; Steinhausen, Manuel; Menten, Karl

2014-10-01

204

Phase-field theory of brine entrapment in sea ice: Short-time frozen microstructures  

E-print Network

We analyze the early phase of brine entrapment in sea ice, using a phase field model. This model for a first-order phase transition couples non-conserved order parameter kinetics to salt diffusion. The evolution equations are derived from a Landau-Ginzburg order parameter gradient dynamics together with salinity conservation. The numerical solution of model equations by an exponential time differencing scheme describes the time evolution of phase separation between liquid water with high salinity and the ice phase with low salinity. The numerical solution in one and two dimensions indicates the formation of one dominant wavelength which sets the length scale of short-time frozen structures. A stability analysis provides the phase diagram in terms of two Landau parameters. It is distinguished an uniform ice phase, a homogeneous liquid saline water solution and a phase where solidification structures can be formed. The Landau parameters are extracted from the supercooling and superheating as well as the freezing point temperature of water. With the help of realistic parameters the distribution of brine inclusions is calculated and found in agreement with the measured samples. The size of the ice domains separating regions of concentrated seawater depends on salinity and temperature and corresponds to the size of sea ice platelets obtained from a morphological stability analysis for the solidification of salt water.

Silke Thoms; Bernd Kutschan; Klaus Morawetz

2014-05-01

205

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

SciTech Connect

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.

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

1999-11-09

206

Experimental study of HBC fuses working at short and medium pre-arcing times  

NASA Astrophysics Data System (ADS)

Pre-arcing stage is the first working step in high breaking capacity (HBC) fuse operation and affects the following step, namely, the arcing step. We have performed realistic HBC fuse tests for short (<10 ms) and medium (>10 ms) pre-arcing times by varying the phase angle of the electrical fault (defined as the phase angle of the fault current once the supplied voltage is applied to the fuse) in the range from 0° to 160°, for two values of the power factor (cosphiv ~ 0.9 and cosphiv ~ 0.1). Experimental values of the pre-arcing time and the arcing time (tarc) are given for tprearc/tarc lsim 1 to ~4.2, and discussed from the energetic point of view by taking into account the inductive source term. The adiabatic assumption classically used in the modelling is also examined. The influence of the pre-arcing step on the arcing step is analysed by means of the Joule integral, the energy dissipated in the fuse and the mass and length of the fulgurite.

Bussière, W.; Rochette, D.; Velleaud, G.; Latchimy, T.; Gelet, J. L.; Gentils, F.; Perez-Quesada, J. C.; Rambaud, T.; André, P.

2008-10-01

207

Grief revisited.  

PubMed

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

Ng, B Y

2005-06-01

208

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

NASA Astrophysics Data System (ADS)

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 from ECMWF. The approach has been tested and is now available on the Web for operational water management.

Kwok Wong, Wai; Hisdal, Hege

2013-04-01

209

Assessing stomatal conductance changes on short and long time scales and its possible impact on climate  

NASA Astrophysics Data System (ADS)

Two fundamental responses of vegetation to increasing atmospheric CO2 concentrations ([CO2]) are increased photosynthesis and decreased stomatal conductance. The latter is determined by both stomatal aperture adjustment on the short term, and by stomatal frequency and size adjustment on the long term. The resulting increased WUE of vegetation leads to changes in the hydrological cycle. Integrating this physiological forcing in Global Circulation Models (GCMs) results in increased surface warming and is thought to enhance terrestrial runoff significantly. Stomatal conductance is therefore considered a critical parameter in modelling past and future climate and environmental changes. However, quantification of the rate of change under [CO2] variability has proven to be not so straightforward. Values obtained from growth experiments under elevated [CO2] generally reflect the short term adaptation only, and seem to have too short a runtime for structural adaptation of the vegetation. Here we present the stomatal conductance changes deduced from Florida subfossil leaves over a 100ppmv [CO2] increment since the industrial revolution. Temporally high-resolution measurements of stomatal frequency and size on the epidermis for 8 common Florida tree species (Taxodium distichum, Pinus elliottii, P. taeda, Quercus nigra, Q. laurifolia, Acer rubrum, Myrica cerifera and Ilex cassine) are used to calculate the maximal stomatal conductance to water vapour Gwmax. Resulting conductance decreases over a 100ppmv [CO2] interval range between -19% to -59% for the different species, with an average of -40%. The current warm-temperate to subtropical Florida climate and vegetation composition serve as a modern analogue for Late Tertiary Europe, when [CO2] is thought to be comparable to today's levels. If it is assumed that past vegetation has responded similarly to [CO2] fluctuations, the stomatal conductance change reconstructed for Florida and related WUE changes can be used to better understand hydrological and climatological changes further back in the geological history. As a corollary we present for the first time stomatal conductance Gwmax from Miocene and Pliocene oak leaves. Mainly the stomatal density changes on these leaves result in significant fluctuations in Gwmax, as a consequence of variation in palaeoatmospheric CO2.

Lammertsma, Emmy; Wagner-Cremer, Friederike; Kuerschner, Wolfram M.

2010-05-01

210

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

211

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

NASA Astrophysics Data System (ADS)

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

Ciolfi, Riccardo; Siegel, Daniel M.

2015-01-01

212

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

E-print Network

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

Riccardo Ciolfi; Daniel M. Siegel

2015-01-27

213

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

PubMed

Diffusion in bidisperse Brownian hard-sphere suspensions is studied by Stokesian Dynamics (SD) computer simulations and a semi-analytical theoretical scheme for colloidal short-time dynamics, based on Beenakker and Mazur's method [Physica A 120, 388-410 (1983); 126, 349-370 (1984)]. Two species of hard spheres are suspended in an overdamped viscous solvent that mediates the salient hydrodynamic interactions among all particles. In a comprehensive parameter scan that covers various packing fractions and suspension compositions, we employ numerically accurate SD simulations to compute the initial diffusive relaxation of density modulations at the Brownian time scale, quantified by the partial hydrodynamic functions. A revised version of Beenakker and Mazur's ??-scheme for monodisperse suspensions is found to exhibit surprisingly good accuracy, when simple rescaling laws are invoked in its application to mixtures. The so-modified ?? scheme predicts hydrodynamic functions in very good agreement with our SD simulation results, for all densities from the very dilute limit up to packing fractions as high as 40%. PMID:25681941

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

2015-02-14

214

Short-time diffusion in concentrated bidisperse hard-sphere suspensions  

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

215

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

PubMed Central

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

2013-01-01

216

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

Microsoft Academic Search

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

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

2010-01-01

217

2$\\\\,\\\\times\\\\,$ 25kV 50 Hz High-Speed Traction Power System: Short-Circuit Modeling  

Microsoft Academic Search

A2 25-kV 50 Hz traction power system was an- alyzed and modeled in the time domain in order to simulate short-circuit conditions and to attain a practical method to iden- tify the short circuit behavior of the traction system. In particular, due to the difficulty in assessing the track-line parameters which mainly depend on changing environmental conditions, the pos- sibility

Luigi Battistelli; Mario Pagano; Daniela Proto

2011-01-01

218

Dynamics of the Markov Time Scale of Seismic Activity May Provide a Short-Term Alert for Earthquakes  

Microsoft Academic Search

We propose a novel method for analyzing precursory seismic data before an earthquake that treats them as a Markov process and distinguishes the background noise from real fluctuations due to an earthquake. A short time (on the order of several hours) before an earthquake the Markov time scale $t_M$ increases sharply, hence providing an alarm for an impending earthquake. To

M. Reza Rahimi Tabar; Muhammad Sahimi; K. Kaviani; M. Allamehzadeh; J. Peinke; M. Mokhtari; M. Vesaghi; M. D. Niry; F. Ghasemi; A. Bahraminasab; S. Tabatabai; F. Fayazbakhsh

2005-01-01

219

Are ecosystem carbon inputs and outputs coupled at short time scales? A case study from adjacent pine and  

E-print Network

Are ecosystem carbon inputs and outputs coupled at short time scales? A case study from adjacent and responses of Rsoil have been found on time scales of hours to weeks for different ecosystems, but most ecosystems over six and four measurement years, respectively, using both autocorrelation analysis

220

Comparison of the short-time Fourier transform and wavelet transform for analysis of transient signal events  

E-print Network

The performance characteristics of the wavelet transform and the short-time Fourier transform (STFT) for transient detection are examined by means of computer simulation. The STFT uses a power-of-two decimation-in-time FFT with various frame sizes...

Pilgrim, Richard Allen

1994-01-01

221

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

222

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

PubMed Central

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

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

2012-01-01

223

Predictive performance of the Short Time Exposure test for identifying eye irritation potential of chemical mixtures.  

PubMed

The Short Time Exposure (STE) test is an in vitro eye irritation test based on the cytotoxicity in SIRC cells (rabbit corneal cell line) following a 5min treatment of chemicals. This study evaluated the predictive performance of the STE test to identify the globally harmonized system (GHS) Not Classified category and other irritant categories (i.e., GHS Category 1 or 2) when used to test 40 chemical mixtures that included irritants. The STE test correctly identified 30 tested mixtures classified as GHS irritant categories and 5 out of 10 tested mixtures classified as GHS Not Classified. The sensitivity, specificity, positive predictivity, negative predictivity, and overall accuracy of the STE test were 100% (30/30), 50% (5/10), 86% (25/30), 100% (5/5), and 88% (35/40), respectively. These predictive performances were comparative to or greater than those in other in vitro eye irritation tests that have been accepted as test guideline by the Organisation for Economic Co-operation and Development. This suggests that the STE test has sufficient predictivity for identifying the eye irritation potential of chemical mixtures. Since no false negatives in this study were found, this indicates that the STE test is applicable as a part of the bottom-up approach. PMID:25681760

Saito, Kazutoshi; Miyazawa, Masaaki; Nukada, Yuko; Ei, Kyo; Abo, Takayuki; Sakaguchi, Hitoshi

2015-04-01

224

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

PubMed

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. PMID:17174003

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

2007-02-01

225

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

PubMed Central

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

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

2008-01-01

226

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

PubMed

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

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

2008-08-01

227

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

PubMed

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. PMID:25605942

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

2015-02-01

228

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

229

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

NASA Astrophysics Data System (ADS)

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.

Wanderman, David; Piran, Tsvi

2015-04-01

230

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

PubMed Central

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

Payton, Karen L.; Shrestha, Mona

2013-01-01

231

Application of the time-delay integration method: Survey observations of geosynchronous orbit objects and short-term variability observations  

NASA Astrophysics Data System (ADS)

"Time-Delay Integration (TDI)" readout technique has been adopted to a mosaic CCD camera equipped with four fully-depleted CCDs. Optical distortion and image deformation due to the TDI operation are discussed. The manner and advantages of the TDI method in survey observations of geosynchronous orbit objects are summarized. We propose a new TDI application method of getting short-term light curves of artificial space objects. This method of detecting a short-term variability can be applied for a variety of objects, ranging from satellites to stars. It can also be used for the light-curve observations of transient objects which might show short-term variability and of which the precise time information is needed.

Okumura, Shin-ichiro; Yanagisawa, Toshifumi; Nakaya, Hidehiko; Tanaka, Wataru; Nishiyama, Kota; Takahashi, Noritsugu; Yoshikawa, Makoto

2014-12-01

232

A coordinated approach for real-time short term hydro scheduling  

SciTech Connect

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

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

1996-11-01

233

32ND INTERNATIONAL COSMIC RAY CONFERENCE, BEIJING 2011 Heliocentric Distance of CMEs at the Time of Energetic Particle Release: Revisit-  

E-print Network

32ND INTERNATIONAL COSMIC RAY CONFERENCE, BEIJING 2011 Heliocentric Distance of CMEs at the Time, and the finite size of the pre-eruption CME structure, we derive the heliocentric release distance particles are released when the CMEs reach an average heliocentric distance of ~3.6 solar radii (Rs

Usoskin, Ilya G.

234

Revisiting Mr. Tall and Mr. Short  

ERIC Educational Resources Information Center

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…

Riehl, Suzanne M.; Steinthorsdottir, Olof Bjorg

2014-01-01

235

Time-resolved diffraction profiles and atomic dynamics in short-pulse laser-induced structural transformations: Molecular dynamics study  

E-print Network

Time-resolved diffraction profiles and atomic dynamics in short-pulse laser-induced structural on the atomic-level structural rearrangements available from the simulations to the diffraction spectra measured of the irradiated surface and provides limited direct information on atomic structural rearrangements. Recent

Zhigilei, Leonid V.

236

The Genetic and Environmental Control of Reproductive Timing in a Short-Lived Monocarpic Species Daucus Carota (Umbelliferae)  

E-print Network

Daucus Carota (Umbelliferae) Elizabeth P. Lacey The Journal of Ecology, Vol. 74, No. 1. (Mar., 1986), pp AND ENVIRONMENTAL CONTROL OF REPRODUCTIVE TIMING IN A SHORT-LIVED MONOCARPIC SPECIES DAUCUS CAROTA (UMBELLIFERAE.S.A. SUMMARY (1) Offspring of annual, biennial and triennial Daucus carota were grown under three nutrient

Lacey, Elizabeth P.

237

Short term effects of air pollution on health: a European approach using epidemiologic time series data: the APHEA protocol  

Microsoft Academic Search

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

K Katsouyanni; J Schwartz; C Spix; G Touloumi; D Zmirou; A Zanobetti; B Wojtyniak; J M Vonk; A Tobias; A Pönkä; S Medina; L Bachárová; H R Anderson

1996-01-01

238

Short time step analysis of vertical ground-coupled heat exchangers: The approach of CaRM  

Microsoft Academic Search

In this paper an improvement of the model CaRM (CApacity Resistance Model) is presented to consider the borehole thermal capacitance, both of the filling material of the borehole and of the heat carrier fluid inside the ground heat exchanger. Several models, numerical and analytical, are available in literature for short time step analyses of ground-coupled heat pump systems. According to

Angelo Zarrella; Massimiliano Scarpa; Michele De Carli

2011-01-01

239

Distributed multichannel speech enhancement with minimum mean-square error short-time spectral amplitude, log-spectral  

E-print Network

Distributed multichannel speech enhancement with minimum mean-square error short-time spectral Keywords: Acoustic arrays Speech enhancement Amplitude estimation Phase estimation Parameter estimation a b on the development and implementation of speech enhancement algorithms. Whereas the current state-of-the-art methods

Johnson, Michael T.

240

When Might a Distressed Firm Share Work? Evidence from the Short-Time Compensation Programme in France  

Microsoft Academic Search

This paper analyses the participation patterns of publicly funded short-time compensation benefits (STC) in France. The regression equation directly models the choice of work units facing slack demand to adjust their labour force by declaring redundancies or by implementing an STC agreement. The likelihood of adopting the work-sharing mode is related to certain firm and labour force attributes, labour market

David M. Gray

1998-01-01

241

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

ERIC Educational Resources Information Center

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…

Yasumitsu, Tatsuo; Nogawa, Haruo; Hatano, Yoshiro

2011-01-01

242

Acquisition, Storage, and Review of Safety Data from a Commercial System for High Temperature, Short Time Pasteurization  

Microsoft Academic Search

A high temperature, short time (HTST) pasteuri- zation system was equipped with electronic sensors to determine the temperature, pressure, flow rate, and position of the flow diversion valve. A computer for data acquisition was wired to the sensors to monitor and to record processing conditions related to public health. The processing conditions were stored in safety files on the hard

J. E. Schlesser; G. Lynn; D. J. Armstrong; A. Cinar; P. Ramanauskas; A. Negiz

1998-01-01

243

Predictive modeling of lactoperoxidase and ?-glutamyl transpeptidase inactivation in a high-temperature short-time pasteurizer  

Microsoft Academic Search

Linear models were derived to describe the thermal inactivation of ?-glutamyl transpeptidase (GGTP) and lactoperoxidase (LP) in bovine milk in a high-temperature short-time (HTST) pilot scale pasteurizer. Integrated lethal effect (pasteurization effect; PE) was related by simple linear functions to the log10 of the % initial activity with a power transformation of the PE values to improve linear fit. The

R. C. McKellar; S. Liou; H. W. Modler

1996-01-01

244

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

NASA Astrophysics Data System (ADS)

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 at a high spatial resolution. REFERENCES Arfeuille, Gilles J. M., A. L. Quintanilla, L. Zizumbo, and F. C. Viesca, 2012. Wind Resource Assessment in a Tropical Region with Complex Terrain using SODAR and a Meteorological Tower Network to Measure Low Level Jets and Boundary Layer Conditions. 15th AMS Conference on Mountain Meteorology, Steam boat Spring, Colorado, USA, August 2012. Available on-line: https://ams.confex.com/ams/15MountMet/webprogram/Manuscript/Paper210184/ARFEUILLLE_etal_15MountMet Conf_Aug2012.pdf Drechsel S., G. J. Mayr, J. W. Messner, and R. Stauffer, 2012: Wind Speeds at Heights Crucial for Wind Energy: Measurements and Verification of Forecasts. J. Appl. Meteor. Climatol., 51, 1602-1617. Rodrigo, J. S., 2010. State-of-the-Art of Wind Resource Assessment. CENER National Renewable Energy Center, Sarriguren, Spain. Available on-line: http://www.waudit-itn.eu/download.php?id=103&parent=79

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

2013-04-01

245

Short-Time Frequency Measurement of Narrow-Band Random Signals in the Presence of Wide-Band Noise  

Microsoft Academic Search

In certain applications it is necessary to measure the center frequency of a symmetrical power spectrum in the shortest possible time. Two instrumentations for short-time frequency measurement, the autocorrelator and the frequency discriminator, are examined for their ability to accomplish this task. The analysis compares the performance of the two systems and indicates the effect of such factors as signal-to-noise

Peter M. Schultheiss; Conrad A. Wogrin; Felix Zweig

1954-01-01

246

Thermal Inactivation of Foot-and-Mouth Disease Virus in Milk Using High-Temperature, Short-Time Pasteurization1  

Microsoft Academic Search

Previousstudiesoflaboratorysimulationofhightem- perature, short time pasteurization (HTST) to elimi- natefoot-and-mouthdiseasevirus(FMDV)inmilkhave shown that the virus is not completely inactivated at the legal pasteurization minimum (71.7°C\\/15 s) but is inactivated in a flow apparatus at 148°C with holding times of 2 to 3 s. It was the intent of this study to determine whether HTST pasteurization conducted in a continuous-flow pasteurizer that simulates

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

2007-01-01

247

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

PubMed Central

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. PMID:25278753

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

2014-01-01

248

Revisiting the Regenerative Possibilities of Ortiz  

ERIC Educational Resources Information Center

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…

Duques, Matthew

2004-01-01

249

Broadcast Flooding Revisited: Survivability and Latency  

E-print Network

Broadcast Flooding Revisited: Survivability and Latency Petteri Mannersalo VTT Technical Research University Email: riedi@rice.edu Abstract--This paper addresses the dynamics of broadcast flooding in random wireless ad hoc networks. In particular, we study the subset of nodes covered by a flood as well as timing

Riedi, Rudolf H.

250

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

PubMed Central

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

Zhivotovsky, Lev A.; Underhill, Peter A.; Cinnio?lu, 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

251

Schroedinger revisited:How the time-dependent wave equation follows from the Hamilton-Jacobi equation  

E-print Network

It is shown how using the classical Hamilton-Jacobi equation one can arrive at the time-dependent wave equation. Although the former equation was originally used by E.Schroedinger to get the wave equation, we propose a different approach. In the first place, we do not use the principle of least action and, in addition, we arrive at the time-dependent equation, while Schroedinger (in his first seminal paper) used the least action principle and obtained the stationary wave equation. The proposed approach works for any classical Hamilton-Jacobi equation. In addition, by introducing information loss into the Hamilton-Jacobi equation we derive in an elementary fashion the wave equations (ranging from the Shroedinger to Klein-Gordon, to Dirac equations). We also apply this technique to a relativistic particle in the gravitational field and obtain the respective wave equation. All this supports 't Hooft's proposal about a possibility of arriving at quantum description from a classical continuum in the presence of information loss.

A. Granik

2004-09-06

252

Investigating oceanic tidal energy dissipation on deep time scales using short tidal deposit sequences  

NASA Astrophysics Data System (ADS)

One of the enduring problems in physical oceanography has been that of tidal dynamics and the effective tidal torque that serves to slow Earth's axial rotation. In the late 20th century, with the aid of satellite altimetry and other technologies, a suite of reliable estimates was finally placed on the magnitude of this torque and other, related parameters in the current epoch. Tidal drag accounts for a 20 microsecond/year increase in mean day length, a 3.5 terawatt dissipation of energy in the oceans (Kantha et al., 1998), and a lunar retreat rate of 3.82 cm/yr (Dickey et al., 1994). Despite these significant advances, however, the problem of tidal dissipation in the geologic past remains largely unresolved. This is due, in part, to difficulties in numerical modeling of past tidal regimes that stem from uncertainties in ocean basin configurations and lunar distances. Tidal deposits can record, to high resolution, the primary astronomical periodicities responsible for the generation of the tidal currents under which transport and deposition occur. With reliable lunar orbital period data obtained from tidal deposits, the past Earth-Moon distance and length of day can be calculated. This task requires careful spectral analysis and consideration of sedimentological factors that may add noise and/or discontinuities to the signal. For deposits representing less than one year of deposition, the necessary assumptions are that Earth's moment of inertia has not changed significantly over the time interval of interest and that the solar component of tidal dissipation can be well-approximated. With consideration of the total angular momentum of the Earth-Moon couplet, we derive a method to calculate lunar distance and length of day. The efficacy of this method and its assumptions is tested via the multi-year sequence of data obtained from the late Precambrian Elatina Formation of Australia and comparing results obtained from the full suite of data by Williams (2000). We go on to analyze a short (3.5 month) Carboniferous dataset from the Abbott Formation of the Illinois Basin, USA. The results suggest non-linearity in ocean tidal dissipation since the late Precambrian and an average lunar retreat rate since the Carbiniferous below the present value, despite a larger lunar distance. With more tidal deposit data analyzed in this way, a much more complete picture of dissipation and Earth-Moon evolution could be realized.

Coughenour, C.

2012-12-01

253

Minimal advective travel time along arbitrary streamlines of porous media flows: The Fermat-Leibnitz-Bernoulli problem revisited  

NASA Astrophysics Data System (ADS)

SummaryTravel time of marked fluid particles along arbitrary streamlines in arbitrary porous streamtubes is estimated from below based on the Cauchy-Bunyakovskii (Schwartz) and Jensen inequalities. In homogeneous media the estimate is strict and expressed through the length of the streamline, hydraulic conductivity, porosity and the head fall. The minimum is attained at streamlines of unidirectional flow. The bounds for heterogeneous soils, non-Darcian flows and unsaturated media are also written. If such bounds are attained the corresponding trajectories become brachistochrones. For example, in a two-layered aquifer and seepage perpendicular to the layers there is a unique conductivity-porosity ratio which makes a broken streamline brachistocronic. Similarly, if conductivities of two layers are fixed there is a unique incident angle between flow in one medium and the interface which makes a refracted streamline brachistocronic.

Kacimov, A. R.; Yakimov, N. D.

2009-09-01

254

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

ERIC Educational Resources Information Center

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…

Laygo, Teresito M., Comp.

255

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

ERIC Educational Resources Information Center

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…

Zelanti, Pierre S.; Droit-Volet, Sylvie

2011-01-01

256

Speech enhancement using MMSE short time spectral estimation with gamma distributed speech priors  

Microsoft Academic Search

In this paper we consider optimal estimators for speech enhancement in the Discrete Fourier Transform (DFT) domain. We present an analytical solution for estimating complex DFT coefficients in the MMSE sense when the clean speech DFT coefficients are Gamma distributed and the DFT coefficients of the noise are Gaussian or Laplace distributed. Compared to the state-of-the-art Wiener or MMSE short

Rainer Martin

2002-01-01

257

Recognition Time for Words in Short-Term, Long-Term, or Both Memory Stores  

ERIC Educational Resources Information Center

The present experiment was designed to investigate recognition memory processes in a task in which the items to be recognized were stored in long-term memory (LTM), in short-term memory (STM), or in both memory stores. (Author/RK)

Mohs, Richard C.; Atkinson, Richard C.

1974-01-01

258

Memorable Messages of Hard Times: Constructing Short and Long-Term Resiliencies Through Family Communication  

Microsoft Academic Search

We take a communicative and life course theory approach to understanding how resilience is constructed in families. Drawing upon interviews with 20 fathers, 16 mothers, and 23 children who dealt with financial hardship during the 1980s recession, we analyze the messages families communicated about finances when their children were young and how these messages contributed to the development of short-

Kristen Lucas; Patrice M. Buzzanell

2012-01-01

259

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

Microsoft Academic Search

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

Wade Enright; Pat Bodger

260

L134N Revisited  

NASA Astrophysics Data System (ADS)

L134N (also known as L183) is a very cold, starless and nearby dark cloud which has attracted much attention from the astrochemists in the past. They have been using it as an oxygen-rich reference to test their models in parallel with TMC-1, the other, but carbon-rich, reference. However, our knowledge of the cloud temperature, structure, and various species abundances has relied for a long time largely on the work by Swade (1987a, 1987b) which suffers from low signal-to-noise C18O and CS maps and limited excitation analysis. This work has been recently repeated and improved by Dickens et al. (2000) but they still lack adequate surface coverage, higher rotational lines of important species and comparison with the dust. While FIRST will probably find many new species in this cloud, it is time to revisit completely this source in order to interpret correctly the FIRST results to come. We have thus made a complete survey of several transitions of CO, 13CO, C18O, C17O, CS, C34S, SO and 34SO species with the NRAO 12-m and CSO 10-m together with maps of the dust from ISO and SCUBA to assess the fundamental properties of this cloud. Preliminary results are reported here.

Pagani, L.; Pardo-Carrion, J. R.; Stepnik, B.

2001-07-01

261

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

E-print Network

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

Evans, Paul G.

262

The Short-Run Effects of Rapid Employment Growth on Travel Time to Work: An Empirical Analysis using Military Troop Movements1  

E-print Network

The Short-Run Effects of Rapid Employment Growth on Travel Time to Work: An Empirical Analysis@primal.ucdavis.edu ABSTRACT This paper examines the short-run impacts of rapid employment growth on travel time to work. We on travel time using instrumental variables, difference-in- differences, and difference

Lin, C.-Y. Cynthia

263

Jan Mayen revisited, the sister volcanoes Sør-Jan and Nord-Jan (Beerenberg) and their evolution through time  

NASA Astrophysics Data System (ADS)

The Island of Jan Mayen is situated at 71°N and 8.3°W in the north Atlantic at the southern edge of the Jan Mayen fracture zone. It is a volcanic island extending for about 53 km from SW towards NE. Maximum width of the island is 15.8 km at its northern tip, while minimum width is only 2.5 km at its centre. The island is built up by two main edifices that have erupted repeatedly, namely Sør-Jan and Nord-Jan or Beerenberg. Petrology of the two edifices is strikingly different. In the south volcanic products are characterized by evolved basalts and trackites to rhyolites. Crystals of ol, cpx, opx are small and in low portions in the rocks. Plg is however common. A 220 m thick plinian formation is found at Borga location in Sør Jan resting on top of a palaeo beach at the altitude of some 170-200 m. This we interpret as caldera formation on Sør Jan and the beach uplift a later stage resurgent activity within the caldera. Further the post caldera volcanic activity all indicates that magma has been stored for shorter or longer time before eruption on surface. Nord Jan or Beerenberg on the other hand shows more primitive magma evolution indicating its younger age. At the flanks of Beerenberg (e.g. Esk krater and Kapp Fishburn) volcanic activity is characterized by ankaramitic magma, with ol, opx and cpx (to lesser extent) in the size range of 1-4 cm and portions up 30% of the whole rock. Plg is absent in these rocks. Volcanic vents closer to the summit area of Beerenberg have smaller ol, cpx and opx (to a lesser extent) and in much lower portion than at the flank eruption sites. These rocks also all carry plg, indicating magma reservoir development and shallow magma residence towards the centre of Beerenberg. We will present a model for the evolution of the Jan Mayen Island, as a migrating volcanism from South towards North. At first the volcanism is characterized by mantle derived magma, namely ankaramites. Prolonged activity forms magma chambers in the crust that eventually lead to caldera formation at the volcano. Post caldera activity is characterized by evolved basalts and trackites.

Hoskuldsson, A.; Gjerlxw, E.; Pedersen, R. B.; Thorseth, I. H.

2011-12-01

264

Revisiting the Uniqueness of Simple Demographics in the US Population  

E-print Network

precisely the degree of privacy of in- dividuals on a scale that goes from uniquely identi- fiable to kRevisiting the Uniqueness of Simple Demographics in the US Population Philippe Golle Palo Alto% of the US population can be uniquely identified by gen- der, ZIP code and full date of birth. This short

Golle, Philippe

265

On the validity of the Boltzmann equation for short range potentials  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

266

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

NASA Astrophysics Data System (ADS)

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 classification. Finally, for PM10, several PM10 measures, NO2 and CO, maximum temperature, wind direction, humidity and BLH, i.e., pollutants related to road traffic emissions and meteorological variables related to atmospheric stability. Moreover, validation results showed that non-linear NN models, on average, perform as well or worse as linear models for NO2, O3 and PM10. The results attained with an independent sample reveal a very good correlation between the predicted and observed values which confirms that linear models generalize well for independent data. The applied methods permit producing, in a simple and cost efficient way, different results for each monitoring station, which allows a good spatial resolution for Lisbon's urban area. Consistent with the performance measures, high pollutants' peak values were reproduced in most cases by each model. The attained results raises good prospects for urban air quality characterization, allowing further developments in order to produce an integrated air quality surveillance system for the area of Lisbon.

Russo, A.; Trigo, R. M.

2012-04-01

267

Short-term Electricity Price Forecasting Based on Grey System Theory and Time Series Analysis  

Microsoft Academic Search

Under deregulated environment, accurate price forecasting provides crucial information for electricity market participants to make reasonable competing strategies. With comprehensive consideration of the influencing factors and the varying rules of the day-ahead electricity price of the PJM electricity market, a short-term electricity price forecasting method based on GM(1,2) and ARMA is proposed, in which the equal-dimension and new-information GM(1,2) model

Ruiqing Wang

2010-01-01

268

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

NASA Astrophysics Data System (ADS)

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.

Itoh, Kosuke; Nakada, Tsutomu

2013-04-01

269

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

NASA Astrophysics Data System (ADS)

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 ? concerning the asymptotic effects of long-range correlation, and the quantity 1-? establishing the amount of uncorrelated fluctuations. We find a correlation between the position in the phase space (?,?) of patients with congestive heart failure and their mortality risk.

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

2003-06-01

270

Exploiting the short - term and long - term channel properties in space and time: Eigenbeamforming concepts for the BS in WCDMA  

Microsoft Academic Search

The deployment of adaptive antennas at base stations considerably increases the spectral efficiency of wireless communication systems. To reduce the computational complexity and increase performance of space-time (ST) processing, processing may take place in reduced dimension, i.e., pre-filtering takes place which is related to linear estimation theory based on second order statistics. To this end, long-term and short-term channel estimates

Christopher Brunner; Wolfgang Utschick; Josef A. Nossek

2001-01-01

271

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

NASA Astrophysics Data System (ADS)

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

Ota, T. A.

2013-10-01

272

Effect of High-Temperature-Short-Time Pasteurization on the Ascorbic Acid, Riboflavin and Thiamin Content of Milk  

Microsoft Academic Search

Equipment. The high-temperature-short-time pasteurization of milk is accomplished by different means and with various types of equipment. An electro-pure pasteurizer, 1 which was part of the equipment for instructing students in various pasteurization processes, was employed for pasteurizing the twenty tots of milk which were included in the experiments reported here. According to the manufacturer, the electro-pure pasteurizer operates on

Arthur D. Holmes; Harry G. Lindquist; Carleton P. Jones; Anne W. Wertz

1945-01-01

273

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

SciTech Connect

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

Ota, T. A. [AWE, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom)] [AWE, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom)

2013-10-15

274

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

PubMed

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. PMID:25280046

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

2014-11-01

275

Fast dynamics in glass-forming polymers revisited  

SciTech Connect

The so called fast-dynamics of glass-forming systems as observed by time of flight (TOF) neutron scattering techniques is revisited. TOF-results corresponding to several glass-forming polymers with different chemical microstructure and glass-transition temperature are presented together with the theoretical framework proposed by the authors to interpret these results. The main conclusion is that the TOF-data can be explained in terms of quasiharmonic vibrations and the particular short time behavior of the segmental dynamics. The segmental dynamics display in the very short time range (t {approx} 2 ps) a crossover from a simple exponential behavior towards a non-exponential regime. The first exponential decay, which is controlled by C-C rotational barriers, can be understood as a trace of the behavior of the system in absence of the effects (correlations, cooperativity, memory effects {hor_ellipsis}) which characterize the dense supercooled liquid like state against the normal liquid state. The non-exponential regime at t > 2 ps corresponds to what is usually understood as {alpha} and {beta} relaxations. Some implications of these results are also discussed.

Colmenero, J.; Arbe, A. [Univ. del Pais Vasco, San Sebastian (Spain). Dept. de Fisica de Materiales; Mijangos, C.; Reinecke, H. [CSIC, Madrid (Spain). Inst. de Ciencia y Tecnologia de Polimeros

1997-12-31

276

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

PubMed

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

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

2015-02-01

277

Ionisation refraction as the cause of space - time modulation of a short intense laser pulse  

SciTech Connect

The three-dimensional dynamics of the propagation of a short intense laser pulse in an ionising material is analysed. The modulation of the temporal profile of the laser pulse caused by the essentially three-dimensional dynamics of its propagation is studied using an analytic model proposed. The criterion for realisation of various scenarios of the pulse propagation in an ionising gas is suggested. The numerical self-consistent analysis of the nonlinear propagation of the pulse in the ionising material showed the correctness of conclusions of the simplest analytic model. (interaction of laser radiation with matter. laser plasma)

Chegotov, M V [Institute for High Energy Densities, Associated Institute for High Temperatures, Russian Academy of Sciences, Moscow (Russian Federation)

2002-01-31

278

Amyoplasia revisited.  

PubMed

Amyoplasia is a specific type and the most common form of arthrogryposis (multiple congenital contractures). It is a clinical diagnosis at this time. Care should be used making the diagnosis because of the implications for recurrence, natural history, associated anomalies, and both etiology and pathogenesis. We reviewed over 600 published reports and 2,500 individual records to identify the 560 individuals reported here. Affected limbs had characteristic positions with fatty-fibrous replacement of muscle. Upper limb involvement was usually characterized by extended elbows. Lower limbs were held in various positions at birth; however, equinovarus positioning of feet was almost always present. Symmetric involvement was common. Among 560 affected individuals, subtypes were identified: four-limb symmetric involvement (331/560 = 55.9%), severe involvement (41/560 = 7.3%), three-limb involvement (27/560 = 4.8%), upper limb only Amyoplasia (ULA; 94/560 = 16.8%), and lower limb only Amyoplasia (LLA; 25/560 = 15.5%). Discordant monozygotic twinning was increased, occurring in 6.6% (37/560; OR 10.9). A variety of additional anomalies were seen, attributed to apparent vascular compromise. Gastrointestinal vascular compromise-type anomalies were present in 9.1% (51/560), trunk muscle defects in another 2.7% (15/560), digit compromise in 12.1% (68/560), constriction rings in 4.3% (24/560), and perinatal long bone fractures in 10.5% (59/560). Although prenatal ultrasound became the standard of care in 1990, only about one quarter of affected pregnancies were diagnosed prenatally since 1990. Amyoplasia appears to be completely sporadic. Novel pathogenetic mechanisms for the congenital anomalies seen in Amyoplasia need to be identified. PMID:24459070

Hall, Judith G; Aldinger, Kimberly A; Tanaka, Kimi I

2014-03-01

279

Human express saccades: extremely short reaction times of goal directed eye movements  

Microsoft Academic Search

Human subjects were asked to execute a saccade from a central fixation point to a peripheral target at the time of its onset. When the fixation point is turned off some time (˜ 200 ms) before target onset, such that there is a gap where subjects see nothing, the distribution of their saccadic reaction times is bimodal with one narrow

B. Fischer; E. Ramsperger

1984-01-01

280

Simulations and Experiments about the Influence of HMME Concentration in Blood Vessel during a Short Time on Photodynamic Therapy Microvascular Effect  

Microsoft Academic Search

Objective: Study the influence of Hematoporphyrin Monomethyl Ether (HMME) concentration in blood vessel in a rather short time on photodynamic therapy (PDT) microvascular effect by mathematical modeling and animal experiment. Methods: The yields of singlet oxygen in blood vessel in a short time in different animal were simulated by mathematical model, and the yields of singlet oxygen in Leghorn Cocks

N. Y. Huang; Y. Gu; F. G. Liu; G. Cheng; Q. H. Zhong; Y. Wang; H. X. Qiu; L. H. Liu; J. Zeng

2007-01-01

281

Panspermia revisited  

NASA Astrophysics Data System (ADS)

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

Horneck, Gerda

282

Short duration winter-time performances of different passive solar systems  

NASA Astrophysics Data System (ADS)

The thermal performance of three full-sized adjoining rooms, each with a different south-facing passive feature, were monitored for two short periods during January to February and February to March. These rooms are Trombe wall cell, a control cell, and a direct gain cell in the NBS passive solar test facility. Data from 436 sensors were collected, including auxiliary energy supplied, continuous air infiltration, temperatures, solar radiation, and wind speed and direction. The test facility, instrumentation, data acquisition system, and procedures and test conditions are described. The performance of the three test cells are compared along with the values of average, controidal, and maximum and minimum air temperatures in the direct gain and Trombe wall cells. Results indicate that regardless of the magnitude of the stratification, the temperature recorded by the sensor placed in the vicinity of the centroid of the cell was nearly equal to the average value of the cell air temperature.

Mahajan, B. M.

1984-08-01

283

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

NASA Astrophysics Data System (ADS)

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

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

2001-10-01

284

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

NASA Astrophysics Data System (ADS)

Time-resolved K-shell x-ray spectra are recorded from sub-100 nm aluminum foils irradiated by 150-fs laser pulses at relativistic intensities of I?2=2×1018 W ?m2/cm2. The thermal penetration depth is greater than the foil thickness in these targets so that uniform heating takes place at constant density before hydrodynamic motion occurs. The high-contrast, high-intensity laser pulse, broad spectral band, and short time resolution utilized in this experiment permit a simplified interpretation of the dynamical evolution of the radiating matter. The observed spectrum displays two distinct phases. At early time, ?500 fs after detecting target emission, a broad quasicontinuous spectral feature with strong satellite emission from multiply excited levels is seen. At a later time, the He-like resonance line emission is dominant. The time-integrated data is in accord with previous studies with time resolution greater than 1 ps. The early time satellite emission is shown to be a signature of an initial large area, high density, low-temperature plasma created in the foil by fast electrons accelerated by the intense radiation field in the laser spot. We conclude that, because of this early time phenomenon and contrary to previous predictions, a short, high-intensity laser pulse incident on a thin foil does not create a uniform hot and dense plasma. The heating mechanism has been studied as a function of foil thickness, laser pulse length, and intensity. In addition, the spectra are found to be in broad agreement with a hydrodynamic expansion code postprocessed by a collisional-radiative model based on superconfiguration average rates and on the unresolved transition array formalism.

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

2002-12-01

285

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

PubMed

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

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

2013-05-01

286

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

PubMed Central

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

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

2013-01-01

287

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...

288

Test of the exponential decay law at short decay times using tau leptons  

Microsoft Academic Search

Quantum mechanics predicts an exponential distribution for the decay time of massive particles. However, deviations are expected for decay times shorter than about 10?13 s in models conjecturing the existence of hidden variables. Following a recent proposal, the decay length distribution of 5843 ? leptons decaying into 3 charged particles was analyzed in search of such a deviation. The deviation

Gideon Alexander; J. Allison; N. Altekamp; K A Ametewee; K. J. Anderson; S. Anderson; S. Arcelli; D A Axen; Georges Azuelos; A. H. Ball; E. Barberio; R. J. Barlow; R. Bartoldus; J Richard Batley; G. Beaudoin; J. Bechtluft; G. A. Beck; C. Beeston; T. Behnke; A. N. Bell; K. W. Bell; G. Bella; Stanislaus Cornelius Maria Bentvelsen; P. Berlich; Siegfried Bethke; O. Biebel; Ian J Bloodworth; J. E. Bloomer; P. Bock; H. M. Bosch; M. Boutemeur; B. T. Bouwens; S. Braibant; P G Bright-Thomas; R. M. Brown; Helfried J Burckhart; C. Burgard; R. Bürgin; P. Capiluppi; R. K. Carnegie; A. A. Carter; J. R. Carter; C. Chang Y; C. Charlesworth; D. G. Charlton; D. Chrisman; S. L. Chu; P. E. L. Clarke; S. G. Clowes; I. Cohen; J. E. Conboy; O. C. Cooke; M. Cuffiani; S. Dado; C. Dallapiccola; G. M. Dallavalle; C L Darling; S. De Jong; L. A. del Pozo; M. S. Dixit; E. do Couto e Silva; E. Duchovni; G. Duckeck; I. P. Duerdoth; U. C. Dunwoody; J. E. G. Edwards; P. G. Estabrooks; H. G. Evans; Franco Luigi Fabbri; B. Fabbro; P. Fath; F. Fiedler; M. Fierro; Margret Fincke-Keeler; H. M. Fischer; R. Folman; D. G. Fong; M. Foucher; H. Fukui; A. Fürtjes; P. Gagnon; A. Gaidot; J. W. Gary; J. Gascon; S. M. Gascon-Shotkin; N. I. Geddes; C. Geich-Gimbel; S. W. Gensler; F. X. Gentit; T. Geralis; G. Giacomelli; P. Giacomelli; R. Giacomelli; V. Gibson; W. R. Gibson; D. M. Gingrich; J. Goldberg; M. J. Goodrick; W. Gorn; C. Grandi; E. Gross; C. Hajdu; G. G. Hanson; M. Hansroul; M. Hapke; C. K. Hargrove; P. A. Hart; C. Hartmann; M. Hauschild; C. M. Hawkes; R. Hawkings; Richard J Hemingway; G. Herten; R. D. Heuer; M. D. Hildreth; J. C. Hill; S. J. Hillier; T. Hilse; P. R. Hobson; D. Hochman; R James Homer; A. K. Honma; D. Horváth; R. Howard; R. E. Hughes-Jones; D. E. Hutchcroft; P. Igo-Kemenes; D. C. Imrie; A. Jawahery; P. W. Jeffreys; H. Jeremie; Martin Paul Jimack; A. Joly; M. Jones; R. W. L. Jones; U. Jost; P. Jovanovic; D A Karlen; T. Kawamoto; Richard K Keeler; R. G. Kellogg; B. W. Kennedy; B. J. King; J. King; J. Kirk; S. Kluth; T. Kobayashi; M. Kobel; D. S. Koetke; T. P. Kokott; S. Komamiya; R V Kowalewski; T. Kress; P. Krieger; J. von Krogh; P. Kyberd; G. D. Lafferty; H. Lafoux; R. Lahmann; W. P. Lai; D. Lanske; J. Lauber; J. G. Layter; A. M. Lee; E. Lefebvre; Daniel Lellouch; J. Letts; L. Levinson; C. Lewis; S. L. Lloyd; F. K. Loebinger; G. D. Long; B. Lorazo; Michael J Losty; J. Ludwig; A. Luig; A. Malik; M. Mannelli; S. Marcellini; C. Markus; A. J. Martin; J. P. Martin; G. Martinez; T. Mashimo; W. Matthews; P. Mättig; W. J. McDonald; J A McKenna; E. A. Mckigney; T. J. McMahon; A. I. McNab; F. Meijers; S. Menke; F. S. Merritt; H. Mes; J. Meyer; Aldo Michelini; G. Mikenberg; D. J. Miller; R. Mir; W. Mohr; A. Montanari; T. Mori; M. Morii; U. Müller; B. Nellen; B. Nijjhar; R. Nisius; S. W. O'Neale; F. G. Oakham; F. Odorici; H. O. Ogren; N. J. Oldershaw; T. Omori; C. J. Oram; M. J. Oreglia; S. Orito; M. Palazzo; J. Pálinkás; F. M. Palmonari; J. P. Pansart; G. Pásztor; J. R. Pater; G. N. Patrick; M. J. Pearce; P. D. Phillips; J. E. Pilcher; J L Pinfold; D. E. Plane; P R Poffenberger; B. Poli; A. Posthaus; T. W. Pritchard; H. Przysiezniak; D. L. Rees; D. Rigby; M. G. Rison; S. A. Robins; N L Rodning; J. M. Roney; E. Ros; A. M. Rossi; M. Rosvick; P. Routenburg; Y. Rozen; K. Runge; O. Runolfsson; D. R. Rust; R. Rylko; E Sarkisyan-Grinbaum; M. Sasaki; C. Sbarra; A. D. Schaile; O. Schaile; F. Scharf; P. Scharff-Hansen; P. Schenk; B. Schmitt; M. Schröder; H. C. Schultz-Coulon; M. Schulz; P. Schütz; J. Schwiening; W. G. Scott; T. G. Shears; B. C. Shen; C. H. Shepherd-Themistocleous; P. Sherwood; G. P. Siroli; A. Sittler; A. Skillman; A. Skuja; A. M. Smith; T. J. Smith; G. A. Snow; Randall J Sobie; S. Söldner-Rembold; R. W. Springer; M. Sproston; A. Stahl; M. Starks; C. Stegmann; K. Stephens; J. Steuerer; B. Stockhausen; D. Strom; F. Strumia; P. Szymanski; R. Tafirout; H. Takeda; P. Taras; S. Tarem; M. Tecchio; N. Tesch; M. A. Thomson; E. von Törne; S. Towers; M. Tscheulin; T. Tsukamoto; E. Tsur; A. S. Turcot; M. F. Turner-Watson; P. Utzat; R. Van Kooten; G. Vasseur; P. Vikas; M G Vincter; E. H. Vokurka; F. Wäckerle; A. Wagner; D. L. Wagner; C. P. Ward; D. R. Ward; J. J. Ward; P. M. Watkins; A. T. Watson; N. K. Watson; P. Weber; P. S. Wells; N. Wermes; B. Wilkens; G. W. Wilson; J. A. Wilson; T. Wlodek; G. Wolf; S A Wotton; T. R. Wyatt; S M Xella; S. Yamashita; G. Yekutieli; V. Zacek

1996-01-01

289

New short-time alignment technique for 70-meter antenna surface panels  

Microsoft Academic Search

With severely limited field modification time for upgrading the 64-m antenna to 70-m diameter, a new shorter time method for aligning the surface panels of the main reflector was needed. For each target on the surface panel, both distance (or range) and elevation angle measurements are made. A new technique for setting the surface panels at zenith look has been

M. S. Katow

1986-01-01

290

SHORT PAPER: A WIRELESS TIME-SYNCHRONIZED COTS SENSOR PLATFORM PART I: SYSTEM ARCHITECTURE  

Microsoft Academic Search

In this paper, we describe an implementation of a ad-hoc, distributed sensor platform that provides synchronized time to its users. By abstracting the time synchronization layer away, we allow developers to focus on the core challenges of their applications (e.g., signal processing, aggregation, routing) rather than dealing with the algorithmic and sys- tems issues that inevitably arise when integrating sensing

Jeremy Elson; Lewis Girod; Deborah Estrin

2002-01-01

291

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

SciTech Connect

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.

DeLong, K.W.; Fittinghoff, D.N.; Ladera, C.L.; Trebino, R. [Sandia National Labs., Livermore, CA (United States); Taft, G.; Rundquist, A.; Murnane, M.M.; Kapteyn, H.C. [Washington State Univ., Pullman, WA (United States). Dept. of Physics; Christov, I.P. [Faculty of Physics, Sofia Univ., Sofia (Bulgaria)

1995-05-01

292

Highly robust X-band LNA with extremely short recovery time  

Microsoft Academic Search

GaN-based low-noise amplifiers (LNAs) recently were shown to provide high ruggedness together with low noise figure. These LNAs allow for simplified receiver architectures, e.g., since no limiter is required to protect the input. This paper for the first time presents an investigation of the recovery time of a highly rugged GaN LNA. The X-band LNA is shown to survive input

Matthias Rudolph; Mike Dewitz; Armin Liero; Ibrahim Khalil; Nidhi Chaturvedi; Christian Wipf; Ralf M. Bertenburg; Justin Miller; J. Wurfl; W. Heinrich; G. Trankle

2009-01-01

293

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

PubMed

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

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

2014-01-01

294

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

PubMed Central

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

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

2014-01-01

295

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

PubMed Central

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

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

2013-01-01

296

Short duration winter-time performances of different passive solar systems  

SciTech Connect

The thermal performance of three full-sized adjoining rooms, each with a different south-facing passive feature, were monitored for two short periods during January-February and February-March, 1984. These rooms are a Trombe wall cell, a control cell, and a direct gain cell in the NBS Passive Solar Test facility. During the experiments data from 436 sensors were collected. The data include: auxiliary energy supplied, continuous air infiltration, temperatures, solar radiation, and wind speed and direction. This report briefly describes the test facility, instrumentation, data acquisition system and procedures and test conditions for the experiments. The report presents representative data and results of a preliminary analysis of the data. It compares the performance of the three test cells, and the values of average, centroidal, maximum and minimum air temperatures in the direct gain and Trombe wall cells. Results indicate that regardless of the magnitude of the stratification the temperature recorded by the sensor placed in the vicinity of the centroid of the cell was nearly equal to the average value of the cell air temperature. The report also compares measured data with the predicted values of (1) the ratios of various solar radiation quantities; and (2) the auxiliary energy required to maintain the fixed value of the lower bound temperature in the test cells. The data and predicted values show good agreement.

Mahajan, B.M.

1984-08-01

297

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

SciTech Connect

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.

Baglioni, P [University of Florence; Chen, Wei-Ren [ORNL; Falus, Peter [ORNL; Faraone, Antonio [National Institute of Standards and Technology (NIST); Fratini, Emiliano [University of Florence; Hong, Kunlun [ORNL; Liu, Yun [National Institute of Standards and Technology (NIST); Porcar, L. [National Institute of Standards and Technology (NIST)

2012-01-01

298

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

USGS Publications Warehouse

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 behavior can be explored to optimize sandbar estimation using video imagery, even in the absence of hydrodynamic data. ?? 2011 Elsevier B.V..

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

2011-01-01

299

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

SciTech Connect

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

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

2013-12-09

300

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

PubMed

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. PMID:17661617

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

301

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

NASA Astrophysics Data System (ADS)

We present time-resolved measurements of the displacement of magnetic domain-walls (DWs) driven by vertical spin-polarized currents in track-shaped magnetic tunnel junctions. In these structures, we observe very high DW velocities (600 m/s) at current densities below 107 A/cm2. We show that the efficient spin-transfer torque combined with a short propagation distance allows avoiding the Walker breakdown process and achieving deterministic, reversible, and fast (?1 ns) DW-mediated switching of magnetic tunnel junction elements, which is of great interest for the implementation of fast DW-based spintronic devices.

Sampaio, Joao; Lequeux, Steven; Metaxas, Peter J.; Chanthbouala, Andre; Matsumoto, Rie; Yakushiji, Kay; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji; Nishimura, Kazumasa; Nagamine, Yoshinori; Maehara, Hiroki; Tsunekawa, Koji; Cros, Vincent; Grollier, Julie

2013-12-01

302

Short time scales of magmatic assimilation from diffusion modeling of multiple elements in olivine  

NASA Astrophysics Data System (ADS)

Open-system processes have a large capacity to modify magma compositions during differentiation. Obtaining the rates of such processes is essential to understanding and constraining the evolution of magmatic systems. Here we quantify the time scales for magmatic assimilation of hydrous mafic to ultramafic cumulates by ascending basalts using the zoning patterns of olivine xenocrysts. Robust diffusion modeling results have been obtained by treating multiple compositional profiles for multiple elements (Fe-Mg, Ni, Mn, Ca) on multiple crystals from multiple flows. We find that the time between assimilation and eruption ranges from a few months to ˜25 yr, although 80% of the results are <10 yr. These ranges are shorter than either magma transport times from the mantle to the surface or typical repose periods of arc volcanoes. Thus, modification of the geochemical and mineralogical features of basalts by assimilation of plutonic rocks is a fast and probably unavoidable magmatic process.

Costa, Fidel; Dungan, Michael

2005-10-01

303

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

NASA Astrophysics Data System (ADS)

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 denitrifier enzyme activity (DEA) and substrate limitation was assessed by the same assay but without addition of glucose and nitrate. Over the entire observation period, soil moisture was the main controlling factor of DEA in all FPZ (correlation between DEA and gravimetric water content with R = 0.74, 0.61 and 0.47 for grass zone, willow bush and mixed forest, respectively, at p<0.01). Considering extractable nitrate and the results from the denitrification assay without nitrate and glucose we conclude that there was some substrate limitation but it was not severe. During the flooding events, DEA responded instantaneously to the changes in soil moisture. Particularly strong denitrification "pulses" were observed 1 to 2 days after peak floods in the grass zone, while the scale of change decreased with distance from the river. A severe substrate limitation in the grass zone was indicated 5 days after the peak of the second flood. N2O emissions did not correlate with DEA. High N2O emissions were measured in the grass zone during the entire period of relatively high soil moisture encompassing the two floods with maximum values shortly after water level fell below the overbank sediment. Smaller N2O emissions during complete or partial saturation of the sediments indicated a smaller proportion of denitrification related N2O vs. N2. In addition, a comparison with the composition of soil solution collected in-situ (in particular nitrate and DOC) will be presented for additional insight into controls and limitations of denitrification.

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

2010-05-01

304

Short communication: lying behavior of lactating dairy cows is influenced by lameness especially around feeding time.  

PubMed

Lameness is considered one of the most common welfare and productive problems in dairy cattle. The objective of this study was to evaluate differences in lying behavior between moderately lame and nonlame lactating cows under commercial conditions. Data were collected from 10 free-stall commercial herds, which were feeding on exactly the same ration once daily. All lactating cows were scored for lameness according to a 1 to 5 locomotion scoring system. Only cows with a lameness score between 1 and 4 were considered in the study. In each herd, between 10 and 15 lame cows (scored as 3 or 4) were chosen, and for each lame cow, a nonlame cow (scored as 1) within the same parity and similar days in milk was also selected. Pendant data loggers were then placed on the right hind leg of each cow for 10 d to record lying behavior at 1-min intervals. In addition, the time of feed delivery was recorded in each herd on a daily basis. Total daily lying time, daily number of lying bouts, lying bout duration, laterality (side of recumbence), and lying behavior around feed delivery time were evaluated using a mixed-effects model that accounted for the fixed effects of lameness, days in milk, parity, and the interaction between parity and lameness, plus the random effects of herd. Total daily lying time (721±24.2 min/d) tended to increase with days in milk, but it was not affected by lameness or parity. Likewise, no differences were found in the number of lying bouts (9.6±0.49/d) or laterality (47±2.6% of time lying on the right side). However, the mean bout duration was longer in lame (89.3±3.89 min) compared with nonlame (80.7±3.90 min) cows. It is interesting that lame cows stood up 13 min later than nonlame cows relative to the time when the ration was delivered. In addition, lame cows lay down 19 min earlier than nonlame ones after the feed was delivered, which implies that nonlame cows spent more time standing, and probably eating, than did lame cows. It was concluded that lame cows have longer lying bouts than nonlame animals, and that lying behavior around feed delivery time may be an effective proxy to identify moderately lame cows. PMID:22939795

Yunta, C; Guasch, I; Bach, A

2012-11-01

305

A short introduction to viscosity solutions and the large time behavior of solutions of  

E-print Network

-Jacobi equations Hitoshi Ishii1 Faculty of Education and Integrated Arts and Sciences, Waseda University, Nishi or young researchers to viscosity solutions and is, of course, an outcome of the lectures delivered], based on the asymptotic monotonicity of a certain functional of the solutions as time goes to infinity

Ishii, Hitoshi

306

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

307

Short-Time Events, Coherence, and Structural Dynamics in Photochemistry of Aqueous Halogenated Transition Metal Dianions  

NASA Astrophysics Data System (ADS)

Ultrafast pump-probe spectroscopy, time-resolved x-ray absorption, and computational photochemistry elucidate the photochemical pathway of hexabromoplatinate dianions that propagates through distortions of nascent penta-bromoplatinate anions caused by Jahn-Teller conical intersections and terminates at aquated product complexes.

Tarnovsky, A. N.; Zheldakov, I. L.; El-Khoury, P. Z.; Pal, S. K.; Mereshchenko, A. S.; Ryazantsev, M. N.; Butaeva, E. V.; Pascher, T.; Uhlig, J.; Milne, C. J.; Johnson, S. L.

2013-03-01

308

Object oriented machine learning with a multicore real-time Java processor: short paper  

Microsoft Academic Search

The term intelligent systems is spreading beyond the data mining and machine learning communities. This presents new challenges that are fundamental to classical problems within object oriented programming and analysis. In this paper we investigate the use of a popular intelligent algorithm on a Java-based processor. The processor is a real-time enabled processor implemented on an FPGA, and we deploy

Rasmus Ulslev Pedersen; Martin Schoeberl

2010-01-01

309

Reexamining Rural Decline: How Changing Rural Classifications and Short Time Frames Affect Perceived Growth  

Microsoft Academic Search

Beale codes are an important tool for examining rural urban differences in socioeconomic trends. However, as population changes, counties' designations also change over time. This feature of Beale codes is commonly overlooked by researchers, yet it has important implications for understanding rural growth. Since the fastest growing counties grow out of their rural status, use of the most recent codes

Georgeanne M. Artz; Peter F. Orazem

2005-01-01

310

Short communication Do rats time filled and empty intervals of equal duration differently?  

Microsoft Academic Search

The goal was to determine whether rats time filled and empty intervals of equal duration differently. Each of five rats was trained for 50 sessions on an instrumental appetitive head entry procedure in which food was available (primed) every 120 s. On \\

Mika L. M. MacInnis

311

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

ERIC Educational Resources Information Center

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…

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

2009-01-01

312

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

E-print Network

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

313

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 ...

314

Google Scholar revisited  

Microsoft Academic Search

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

Péter Jacsó

2008-01-01

315

Anodic Polarization Curves Revisited  

ERIC Educational Resources Information Center

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…

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

2013-01-01

316

Technological innovation processes revisited  

Microsoft Academic Search

This work is part of an inquiry into the causes of the small occurrence of innovations in the Brazilian society. It was based on a retrospective analysis of cases experienced by the author, as well as on the study of certain industries. The systemic model of the technological innovation process presented here, while revisiting the models in the literature, emphasizes

Antonio Cantisani

2006-01-01

317

Revisiting Curriculum Potential  

ERIC Educational Resources Information Center

This article analyzes the notion of curriculum potential by revisiting the ideas of Miriam Ben-Peretz and Joseph Schwab. Invoking the German "Didaktik" tradition and by way of a curriculum-making framework, the paper argues that interpreting curriculum materials for curriculum potential requires a careful analysis and unpacking of the meanings and…

Deng, Zongyi

2011-01-01

318

Colloquial Hebrew Imperatives Revisited  

ERIC Educational Resources Information Center

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…

Bolozky, Shmuel

2009-01-01

319

Concept Image Revisited  

ERIC Educational Resources Information Center

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…

Bingolbali, Erhan; Monaghan, John

2008-01-01

320

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

PubMed Central

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

Liebherr, Magnus; Haas, Christian T.

2014-01-01

321

Multiscale approach combining nonadiabatic dynamics with long-time radiative and non-radiative decay: dissociative ionization of heavy rare-gas tetramers revisited.  

PubMed

A multiscale approach is proposed to address short-time nonadiabatic dynamics and long-time decay. We show the role of both radiative and non-radiative processes in cluster decay mechanisms on examples of rare-gas cluster fragmentation after electron impact ionization. Nonadiabatic molecular dynamics is used as an efficient tool for theoretical study on femto- and picosecond scales and a multiscale approach based on kinetic rates of radiative as well as non-radiative transitions, both considered as parallel reaction channels, is used for the analysis of the long-time system relaxation spanning times over microseconds to infinity. While the radiative processes are typically slow, the system relaxation through non-radiative electronic transitions connected with electron-nuclear interchange of energy may, on the other hand, significantly vary in kinetic rates according to kinetic couplings between relevant adiabatic states. While the predictions of picosecond molecular dynamics themselves fail, the results of the multiscale model for the electron-impact post-ionization fragmentation of krypton and xenon tetramers are in agreement with experiment, namely, in leading to the conclusion that charged monomers prevail. More specifically, on microsecond and longer scales, mainly slow radiative processes are substantial for krypton cluster decay, while for xenon the radiative and slow non-radiative processes compete. In general, the role of slow decay processes through non-radiative transitions is comparable with the role of radiative decay mechanism. The novel multiscale model substantially improves theoretical predictions for the xenon tetramer decay and also further improves the good agreement between theory and experiment we reached previously for krypton. PMID:23387580

Jane?ek, Ivan; Jan?a, Tomáš; Naar, Pavel; Kalus, René; Gadea, Florent Xavier

2013-01-28

322

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)

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.

Cunha, Mário; Richter, Christian

2012-03-01

323

New short-time alignment technique for 70-meter antenna surface panels  

NASA Astrophysics Data System (ADS)

With severely limited field modification time for upgrading the 64-m antenna to 70-m diameter, a new shorter time method for aligning the surface panels of the main reflector was needed. For each target on the surface panel, both distance (or range) and elevation angle measurements are made. A new technique for setting the surface panels at zenith look has been devised. This article describes the software required to convert the computed target distortions obtained from the JPL-IDEAS structural analysis computer program (defining the gravity load change from a 45-deg elevation angle to zenith look) into the theodolite reading at zenith look. The technique results in a perfectly shaped reflector at the 45-deg rigging elevation, with acceptable surface error tolerance.

Katow, M. S.

1986-08-01

324

Expression of flowering-time genes in soybean E1 near-isogenic lines under short and long day conditions.  

PubMed

Control of soybean flowering time is important for geographic adaptation and maximizing yield. Plant breeders have identified a series of genes (E genes) that condition time to flowering; however, the molecular basis in the control of flowering by these E genes, in conjunction with canonical flowering-time genes, has not been studied. Time to flowering in near-isogenic lines (NILs) at the E1 locus was tested using a reciprocal transfer experiment under short day (SD) and long day (LD) conditions. Beginning 8 days after planting, three plant samples were harvested every 3 h for a 48-h period. RNA was isolated from these plants, and RNA samples were pooled for each line and each time period for cDNA synthesis. RT-PCR analysis was performed using primers synthesized for a number of putative flowering-time genes based on homology of soybean EST and genomic sequences to Arabidopsis genes. The results of the reciprocal transfer experiment suggest that the pre-inductive photoperiod-sensitive phase of the E1 NILs responsible for inducing flowering is perceived as early as 5-7-day post-planting. No gene expression differences were found between the E1 and e1 NILs, suggesting that the E1 gene does not directly affect the flowering-time genes during the time period tested; however, differences were observed in gene expression between SD and LD treatments for the putative soybean TOC1, CO, and FT genes. The gene expression results in this study were similar to those of flowering-time genes found in other SD species, suggesting that the selected genes correspond to the soybean flowering-time orthologs. PMID:20091337

Thakare, Dhiraj; Kumudini, Saratha; Dinkins, Randy D

2010-03-01

325

Flow Characteristics of a Pilot-Scale High Temperature, Short Time Pasteurizer  

Microsoft Academic Search

In this study, we present a method for determining the fastest moving particle (FMP) and residence time distribution (RTD) in a pilot-scale high temperature, shorttime(HTST)pasteurizertoensurethatlaboratory or pilot-scale HTST apparatus meets the Pasteurized Milk Ordinance standards for pasteurization of milk andcanbeusedforobtainingthermalinactivationdata. The overall dimensions of the plate in the pasteurizer were 75 × 115 mm, with a thickness of 0.5 mm

P. M. Tomasula; M. F. Kozempel

2004-01-01

326

Coherent averaging of the passive fathometer response using short correlation time  

E-print Network

experimental data.1­3,8,9 The technique relies on surface generated noise from wind and waves.10,11 Ship- ping s and, for correlation times less than a few seconds, the observed sig- nal-to-noise ratio (SNR) agrees-correlation of ambient noise data from a drifting vertical array, has been the subject of much discussion in recent years

Gerstoft, Peter

327

Short-time Scale VRI And H? Monitoring Of MWC349  

NASA Astrophysics Data System (ADS)

We have monitored the peculiar emission line star MWC349 for several months in the V, R, I bands and with H-alpha interference filters using the 24” telescope and CCD camera of the Maria Mitchell Observatory on Nantucket Island. Control observations in H-alpha were carried out periodically with the 16” RCOS telescope and CCD camera in Fort Davis, TX. No reliable variations with the time scale shorter than one day were detected in any color band, with an upper limit of +/- 0.05 mag. Sporadic variations of up to 0.1 mag are possible in H-alpha and other filters on a time scale of a week, but this result requires verification. We reliably detected a month time scale drift of brightness in H-alpha and R, with the rates of 0.057 and 0.037 mag per month, respectively, and, less reliably, a similar drift in V and I, with a smaller rate ( 0.02 mag per month). We will discuss the possibility of interpreting the observed color dependence of the rate of drift in terms of varying temperature and size of the central source. This project was supported by the NSF/REU grant AST-0354056 and the Nantucket Maria Mitchell Association.

Aliotta, Paul; Strelnitski, V.; Walker, G.; Armstrong, P.

2007-12-01

328

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

PubMed Central

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

Ebrahimi, Mehregan; Bull, C. Michael

2014-01-01

329

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

PubMed

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 3d. 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 16h postinfusion. Milk concentrations had fallen well below the MIC by the 24-h period (before the next infusion). All 8 cows in this study consistently had individual quarter milk ampicillin concentrations below the FDA tolerance of 0.01?g/mL (10 ppb) within 48h of the last infusion. Based on this study, milk ampicillin concentrations exceed the minimum inhibitory concentration required to inhibit the growth of 90% of organisms (MIC90) for at least 65% of the dosing interval, which is sufficient for once-daily dosing with most cases of gram-positive mastitis. Therefore, intramammary hetacillin should be an effective treatment for the vast majority of gram-positive mastitis pathogens when used according to label (once per day) in cows milked 3 times per day. PMID:25547305

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

2015-03-01

330

Setting the revisit interval in primary care  

Microsoft Academic Search

OBJECTIVE: Although longitudinal care constitutes the bulk of primary care, physicians receive little guidance on the fundamental question\\u000a of how to time follow-up visits. We sought to identify important predictors of the revisit interval and to describe the variability\\u000a in how physicians set these intervals when caring for patients with common medical conditions.\\u000a \\u000a \\u000a DESIGN: Cross-sectional survey of physicians performed at

Lisa M. Schwartz; Steven Woloshin; John H. Wasson; Roger A. Renfrew; H. Gilbert Welch

1999-01-01

331

Effects of short-term psychological stress on the time and frequency domains of heart-rate variability.  

PubMed

The purpose of this study was to test the hypothesis that short-term psychological stress produces significant changes in sympathovagal activity. A simple, noninvasive method was used measuring the timing and frequency of heart-rate variability (HRV). 30 normal healthy subjects were assigned into two age- and sex matched groups. In the experimental condition a 5-min. psychological stress test, predominantly based on the Stroop Word Color Conflict Test, was employed in a competitive setting and included a financial inducement to produce psychological strain. Analysis showed that during psychological stress a significant reduction in the timing and frequency of heart rate variability was observed. The standard deviation of interbeat intervals decreased. A significant increase in heart rate was also observed. Within the frequency domain, a significant reduction in the high frequency component of HRV and a significant increase in the low frequency component were observed. There was also a significant increase in the low frequency to high frequency ratio. Self-evaluation of physical tension and emotional state measured by visual analog scales also showed significant increases following psychological stress. No significant differences were observed on any variables within the control group. The results indicate a shift towards sympathetic predominance as a result of parasympathetic withdrawal and demonstrates that this psychological stress test is effective in provoking a characteristic defence-arousal reaction. This simple, cost-effective method of analysing heart rate variability is suitable for detection of short-term changes in sympathovagal balance. PMID:11065312

Delaney, J P; Brodie, D A

2000-10-01

332

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

PubMed

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

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

2014-02-01

333

Dynamics of the Markov Time Scale of Seismic Activity May Provide a Short-Term Alert for Earthquakes  

E-print Network

We propose a novel method for analyzing precursory seismic data before an earthquake that treats them as a Markov process and distinguishes the background noise from real fluctuations due to an earthquake. A short time (on the order of several hours) before an earthquake the Markov time scale $t_M$ increases sharply, hence providing an alarm for an impending earthquake. To distinguish a false alarm from a reliable one, we compute a second quantity, $T_1$, based on the concept of extended self-similarity of the data. $T_1$ also changes strongly before an earthquake occurs. An alarm is accepted if {\\it both} $t_M$ and $T_1$ indicate it {\\it simultaneously}. Calibrating the method with the data for one region provides a tool for predicting an impending earthquake within that region. Our analysis of the data for a large number of earthquakes indicate an essentially zero rate of failure for the method.

Tabar, M R R; Kaviani, K; Allameh-Zadeh, M; Peinke, J; Mokhtari, M; Vesaghi, M; Niry, M D; Ghasemi, F; Bahraminasab, A; Tabatabai, S; Fayazbakhsh, F; Sahimi, Muhammad

2005-01-01

334

A short target real-time RT-PCR assay for detection of pestiviruses infecting cattle.  

PubMed

A rapid single step real-time duplex TaqMan RT-PCR was developed for detection of bovine viral diarrhoea virus (BVDV)-1, BVDV-2 and border disease virus (BDV). Based on alignment of available and newly generated partial 5'-UTR nucleotide sequences, one forward and two reverse primers were designed, which amplify a 104bp PCR product. Two TaqMan probes labelled with different fluorochromes were designed to detect BVDV-1/BVDV-2 and BDVs, respectively. The assay was able to detect a selection of strains and isolates that represent the genetic diversity of these three viruses, with an analytical sensitivity that corresponded to 3.6, 48 and 4.8 TCID(50) of BVDV-1, BVDV-2 and BDV, respectively. With an overall cycling time of around 70 min, the assay allows rapid diagnosis and efficient use of modern thermocycling machines. Although developed principally for the diagnosis of BVD, the assay should be equally useful for diagnosis of BD in sheep. PMID:19523981

La Rocca, S A; Sandvik, T

2009-10-01

335

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

PubMed

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

Jusot, Jean-François; Alto, Oumarou

2011-11-01

336

Computation of Nonlinear Parameters of Heart Rhythm Using Short Time ECG Segments  

PubMed Central

We propose the method to compute the nonlinear parameters of heart rhythm (correlation dimension D2 and correlation entropy K2) using 5-minute ECG recordings preferred for screening of population. Conversion of RR intervals' time series into continuous function x(t) allows getting the new time series with different sampling rate dt. It has been shown that for all dt (250, 200, 125, and 100?ms) the cross-plots of D2 and K2 against embedding dimension m for phase-space reconstruction start to level off at m = 9. The sample size N at different sampling rates varied from 1200 at dt = 250?ms to 3000 at dt = 100?ms. Along with, the D2 and K2 means were not statistically different; that is, the sampling rate did not influence the results. We tested the feasibility of the method in two models: nonlinear heart rhythm dynamics in different states of autonomous nervous system and age-related characteristics of nonlinear parameters. According to the acquired data, the heart rhythm is more complex in childhood and adolescence with more influential parasympathetic influence against the background of elevated activity of sympathetic autonomous nervous system. PMID:25688286

Koichubekov, Berik; Korshukov, Ilya; Omarbekova, Nazgul; Riklefs, Viktor; Sorokina, Marina; Mkhitaryan, Xenia

2015-01-01

337

Short time-scale frequency and amplitude variations in the pulsations of an roAp star: HD 217522  

NASA Astrophysics Data System (ADS)

Photometric observations of HD 217522 in 1981 revealed only one pulsation frequency ?1 = 1.215 29 mHz. Subsequent observations in 1989 showed the presence of an additional frequency ?2 = 2.0174 mHz. New observations in 2008 confirm the presence of the mode with ?2 = 2.0174 mHz. Examination of the 1989 data shows amplitude modulation over a time-scale of the order of a day, much shorter than what has been observed in other rapidly oscillating Ap (roAp) stars. High spectral and time resolution data obtained using the Very Large Telescope in 2008 confirm the presence of ?2 and short-term modulations in the radial velocity amplitudes of rare earth elements. This suggests growth and decay times shorter than a day, more typical of solar-like oscillations. The driving mechanism of roAp stars and the Sun are different, and the growth and decay seen in the Sun are due to stochastic nature of the driving mechanism. The driving mechanism in roAp stars usually leads to mode stability on a longer time-scale than in the Sun. We interpret the reported change in ?1 between the 1982 and 1989 data as part of the general frequency variability observed in this star on many time-scales.

Medupe, R.; Kurtz, D. W.; Elkin, V. G.; Mguda, Z.; Mathys, G.

2015-01-01

338

Despite strong lobbying, congestion pricing falls short for the time being in New York City  

NSDL National Science Digital Library

Terror police to track capital's carshttp://www.timesonline.co.uk/tol/news/uk/crime/article2091023.eceTransportation Alternatives: Congestion Pricinghttp://www.transalt.org/campaigns/sensible/congestion.htmlImplementing Road and Congestion Pricing-Lessons From Singapore (2005) [pdf]http://www.cleanairnet.org/caiasia/1412/article-71464.htmlStraphangers Campaignhttp://www.straphangers.org/Annals of Transport: There and Back Againhttp://www.newyorker.com/reporting/2007/04/16/070416fa_fact_paumgartenCongestion of the vehicular sort is a problem that continues to vex major cities across the world. Whether it be a long line of cars moving like slow-moving maple syrup off an exit from a so-called "expressway" or a phalanx of delivery trucks double-parked, congestion results in lost productivity and at times, even maddening frustration. Some cities, such as London and Singapore, have adopted congestion pricing schemes for vehicles entering certain roadways, districts, tunnels, or bridges during peak travel times. London has had a scheme in place like this since 2003, and Singapore has had one since 1975. Mayor Michael Bloomberg of New York was rather keen on starting one as part of the city's long-term sustainability plan, but it was shelved earlier this week. Appropriately enough, Bloomberg floated the congestion pricing idea on Earth Day 2007, but legislators in the state capitol of Albany said that Bloomberg didn't address a number of rather basic questions about his proposal. After the proposal failed to pass this past Monday, Bloomberg commented, "I heard a lot of talk about the politics of congestion pricing, and all I kept thinking about was some people have guts, and some don't." To enter the world of congestion pricing, visitors should start by reading through the first link, which happens to be a piece on the recent debate over introducing such a measure in New York which appeared in this Tuesday's New York Times. The second link will take interested parties to a piece from the Times of London which talks about how the congestion charge cameras in London will be used to address the "enduring threat" of terrorist car bombings. Moving on, the third link leads to a primer on congestion pricing offered by the Transportation Alternatives organization. The fourth link will whisk users away to a paper and presentation on the subject of implementing road and congestion pricing authored by Jeremy Yap, who serves as the deputy director for Singapore's Ministry of Transport. The fifth link leads to the homepage of New York's famed Straphangers Campaign, which has been advocating for the city's subway and bus riders since 1979. Here visitors can view awards as the "Pokeys" (slowest buses in the city) and lists of "The Unreliables", which are buses that tend to arrive in bunches or with big gaps during the day. Of course, there are also polls, reports, and a "Fun & Games" section. The last link leads to a very nice article from the April 16, 2007 New Yorker. This article documents, in great detail, what can only be described as "extreme commuting" on the part of stoic individuals in San Jose, Atlanta, and other regions around the US.

2007-01-01

339

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

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

340

Control of insects and mites in grain using a high temperature/short time (HTST) technique.  

PubMed

Wheat infested with grain mites (Acari) and Sitophilus granarius, and maize infested with Prostephanus truncatus, were exposed to hot air in a CIMBRIA HTST Microline toaster((R)). Inlet temperatures of the hot air were in the range of 150-750 degrees C decreasing to outlet temperatures in the range of 100-300 degrees C during the exposure period. A rotating drum, connected to a natural-gas burner was fed with grain which was in constant movement along the drum and thereby mixed thoroughly during the process. The capacity of the toaster was 1000 kg per hour.Complete control of grain mites and adult S. granarius in wheat was obtained with an inlet temperature of 300-350 degrees C and an average residence time in the drum of 6 s. More than 99% mortality was obtained for all stages of S. granarius with an inlet temperature of 300-350 degrees C and an average exposure period of 40 s. For control of P. truncatus in maize, an inlet temperature of 700 degrees C resulted in a complete disinfestation when the exposure time was 19 s.The reduction in grain moisture content was 0.5-1% at treatments giving 100% control. Germination tests indicate that it is possible to choose a combination of inlet temperatures and exposure periods which effectively kills mites and insects in small grains, without harming the functional properties of the grain.Economy of the method was considered to be competitive with fumigation using phosphine. PMID:10758269

Mourier; Poulsen

2000-07-01

341

A Short–Time Scale Colloidal System Reveals Early Bacterial Adhesion Dynamics  

PubMed Central

The development of bacteria on abiotic surfaces has important public health and sanitary consequences. However, despite several decades of study of bacterial adhesion to inert surfaces, the biophysical mechanisms governing this process remain poorly understood, due, in particular, to the lack of methodologies covering the appropriate time scale. Using micrometric colloidal surface particles and flow cytometry analysis, we developed a rapid multiparametric approach to studying early events in adhesion of the bacterium Escherichia coli. This approach simultaneously describes the kinetics and amplitude of early steps in adhesion, changes in physicochemical surface properties within the first few seconds of adhesion, and the self-association state of attached and free-floating cells. Examination of the role of three well-characterized E. coli surface adhesion factors upon attachment to colloidal surfaces—curli fimbriae, F-conjugative pilus, and Ag43 adhesin—showed clear-cut differences in the very initial phases of surface colonization for cell-bearing surface structures, all known to promote biofilm development. Our multiparametric analysis revealed a correlation in the adhesion phase with cell-to-cell aggregation properties and demonstrated that this phenomenon amplified surface colonization once initial cell-surface attachment was achieved. Monitoring of real-time physico-chemical particle surface properties showed that surface-active molecules of bacterial origin quickly modified surface properties, providing new insight into the intricate relations connecting abiotic surface physicochemical properties and bacterial adhesion. Hence, the biophysical analytical method described here provides a new and relevant approach to quantitatively and kinetically investigating bacterial adhesion and biofilm development. PMID:18613749

Beloin, Christophe; Houry, Ali; Froment, Manuel; Ghigo, Jean-Marc; Henry, Nelly

2008-01-01

342

A new monitor set for the determination of neutron flux parameters in short-time k0-NAA  

NASA Astrophysics Data System (ADS)

Multipurpose research reactors such as LVR-15 in ?ež require monitoring of the neutron flux parameters ( f, ?) in each batch of samples analyzed when k0 standardization in NAA is to be used. The above parameters may change quite unpredictably, because experiments in channels adjacent to those used for NAA require an adjustment of the reactor operation parameters and/or active core configuration. For frequent monitoring of the neutron flux parameters the bare multi-monitor method is very convenient. The well-known Au-Zr tri-isotopic monitor set that provides a good tool for determining f and ? after long-time irradiation is not optimal in case of short-time irradiation because only a low activity of the 95Zr radionuclide is formed. Therefore, several elements forming radionuclides with suitable half-lives and Q0 and ?r parameters in a wide range of values were tested, namely 198Au, 56Mn, 88Rb, 128I, 139Ba, and 239U. As a result, an optimal mixture was selected consisting of Au, Mn, and Rb to form a well suited monitor set for irradiation at a thermal neutron fluence rate of 3×10 17 m -2 s -1. The procedure of short-time INAA with the new monitor set for k0 standardization was successfully validated using the synthetic reference material SMELS 1 and several matrix reference materials (RMs) representing matrices of sample types frequently analyzed in our laboratory. The results were obtained using the Kayzero for Windows program.

Kubešová, Marie; Ku?era, Jan; Fikrle, Marek

2011-11-01

343

Flexible mate choice when mates are rare and time is short  

PubMed Central

Female mate choice is much more dynamic than we once thought. Mating decisions depend on both intrinsic and extrinsic factors, and these two may interact with one another. In this study, we investigate how responses to the social mating environment (extrinsic) change as individuals age (intrinsic). We first conducted a field survey to examine the extent of natural variation in mate availability in a population of threespine sticklebacks. We then manipulated the sex ratio in the laboratory to determine the impact of variation in mate availability on sexual signaling, competition, and mating decisions that are made throughout life. Field surveys revealed within season heterogeneity in mate availability across breeding sites, providing evidence for the variation necessary for the evolution of plastic preferences. In our laboratory study, males from both female-biased and male-biased treatments invested most in sexual signaling late in life, although they competed most early in life. Females became more responsive to courtship over time, and those experiencing female-biased, but not male-biased sex ratios, relaxed their mating decisions late in life. Our results suggest that social experience and age interact to affect sexual signaling and female mating decisions. Flexible behavior could mediate the potentially negative effects of environmental change on population viability, allowing reproductive success even when preferred mates are rare. PMID:24101975

Tinghitella, Robin M; Weigel, Emily G; Head, Megan; Boughman, Janette W

2013-01-01

344

Operating envelope of a short contact time fuel reformer for propane catalytic partial oxidation  

NASA Astrophysics Data System (ADS)

Fuel cell technology has yet to realize widespread deployment, in part because of the hydrogen fuel infrastructure required for proton exchange membrane systems. One option to overcome this barrier is to produce hydrogen by reforming propane, which has existing widespread infrastructure, is widely used by the general public, easily transported, and has a high energy density. The present work combines thermodynamic modeling of propane catalytic partial oxidation (cPOx) and experimental performance of a Precision Combustion Inc. (PCI) Microlith® reactor with real-time soot measurement. Much of the reforming research using Microlith-based reactors has focused on fuels such as natural gas, JP-8, diesel, and gasoline, but little research on propane reforming with Microlith-based catalysts can be found in literature. The aim of this study was to determine the optimal operating parameters for the reformer that maximizes efficiency and minimizes solid carbon formation. The primary parameters evaluated were reformate composition, carbon concentration in the effluent, and reforming efficiency as a function of catalyst temperature and O2/C ratio. Including the lower heating values for product hydrogen and carbon monoxide, efficiency of 84% was achieved at an O2/C ratio of 0.53 and a catalyst temperature of 940 °C, resulting in near equilibrium performance. Significant solid carbon formation was observed at much lower catalyst temperatures, and carbon concentration in the effluent was determined to have a negative linear relationship at T < 750 °C. The Microlith reactor displayed good stability during more than 80 experiments with temperature cycling from 360 to 1050 °C.

Waller, Michael G.; Walluk, Mark R.; Trabold, Thomas A.

2015-01-01

345

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

PubMed

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. PMID:22239926

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

2012-03-01

346

A Distributed Web-based Solution for Ionospheric Model Real-time Management, Monitoring, and Short-term Prediction  

NASA Astrophysics Data System (ADS)

With the widespread availability of the Internet today, many people can monitor various scientific research activities. It is important to accommodate this interest providing on-line access to dynamic and illustrative Web-resources, which could demonstrate different aspects of ongoing research. It is especially important to explain and these research activities for high school and undergraduate students, thereby providing more information for making decisions concerning their future studies. Such Web resources are also important to clarify scientific research for the general public, in order to achieve better awareness of research progress in various fields. Particularly rewarding is dissemination of information about ongoing projects within Universities and research centers to their local communities. The benefits of this type of scientific outreach are mutual, since development of Web-based automatic systems is prerequisite for many research projects targeting real-time monitoring and/or modeling of natural conditions. Continuous operation of such systems provide ongoing research opportunities for the statistically massive validation of the models, as well. We have developed a Web-based system to run the University of Alaska Fairbanks Polar Ionospheric Model in real-time. This model makes use of networking and computational resources at the Arctic Region Supercomputing Center. This system was designed to be portable among various operating systems and computational resources. Its components can be installed across different computers, separating Web servers and computational engines. The core of the system is a Real-Time Management module (RMM) written Python, which facilitates interactions of remote input data transfers, the ionospheric model runs, MySQL database filling, and PHP scripts for the Web-page preparations. The RMM downloads current geophysical inputs as soon as they become available at different on-line depositories. This information is processed to provide inputs for the next ionospheic model time step and then stored in a MySQL database as the first part of the time-specific record. The RMM then performs synchronization of the input times with the current model time, prepares a decision on initialization for the next model time step, and monitors its execution. Then, as soon as the model completes computations for the next time step, RMM visualizes the current model output into various short-term (about 1-2 hours) forecasting products and compares prior results with available ionospheric measurements. The RMM places prepared images into the MySQL database, which can be located on a different computer node, and then proceeds to the next time interval continuing the time-loop. The upper-level interface of this real-time system is the a PHP-based Web site (http://www.arsc.edu/SpaceWeather/new). This site provides general information about the Earth polar and adjacent mid-latitude ionosphere, allows for monitoring of the current developments and short-term forecasts, and facilitates access to the comparisons archive stored in the database.

Kulchitsky, A.; Maurits, S.; Watkins, B.

2006-12-01

347

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

NASA Astrophysics Data System (ADS)

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.

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

2008-11-01

348

Line emission radiation during early-time interaction of an intense short laser pulse with an ultrathin planar aluminum target  

NASA Astrophysics Data System (ADS)

The interaction of an intense short laser pulse with an ultrathin planar aluminum foil is investigated with a fully relativistic particle-in-cell model self-consistently coupled to an atomic dynamics model describing the non-local thermodynamic equilibrium level population dynamics and radiative behavior of a plasma evolving on a picosecond timescale. For typical experimental conditions, laser pulses with energy 1 J, intensity 1020 W cm?2, and duration 40 fs, a synthetic spectrum for the emission lines is generated as a function of time for lines emanating in the hydrogen- and helium-like ionization stages. It is found that He?, He?, Ly?, and Ly? lines have intensities above the Bremsstrahlung continuum and could serve as diagnostics for the evolving plasma condition.

Davis, J.; Petrov, G. M.; Petrova, Tz B.

2015-04-01

349

“It’s time for your life”: How should we remind patients to take medicines using short text messages?  

PubMed Central

The objective of this paper is to characterize effective patient care reminder strategies for people living with HIV/AIDS (PLWHA) to improve antiretroviral therapy (ART) adherence) using short message service (SMS) based on patient perspectives. We conducted a qualitative study with adult PLWHA in a community-based clinic in Lima, Peru using focus groups. 26 HIV-positive individuals participated in four focus groups (20 men, 6 women). The participants expressed positive perceptions towards receiving reminders via SMS, but specified certain characteristics they wanted them to have (such as being simple and concise). It was also important that the messages maintained confidentiality and privacy by using coded words or phrases (“Remember, it is the time of your life”) instead of “sensitive” words (HIV or antiretroviral). This study suggests that patients want healthcare SMS that appropriately notify them, deliver a careful crafted message, and assess the context in which they are received. PMID:21633523

Curioso, Walter H.; Alex Quistberg, D.; Cabello, Robinson; Gozzer, Ernesto; Garcia, Patricia J.; Holmes, King K.; Kurth, Ann E.

2009-01-01

350

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

NASA Technical Reports Server (NTRS)

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

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

1960-01-01

351

Performance of short-time spectral parametric methods for reducing the variance of the Doppler ultrasound mean instantaneous frequency estimation.  

PubMed

To achieve an accurate estimation of the instantaneous turbulent velocity fluctuations downstream of prosthetic heart valves in vivo, the variability of the spectral method used to measure the mean frequency shift of the Doppler signal (i.e. the Doppler velocity) should be minimised. This paper investigates the performance of various short-time spectral parametric methods such as the short-time Fourier transform, autoregressive modelling based on two different approaches, autoregressive moving average modelling based on the Steiglitz-McBride method, and Prony's spectral method. A simulated Doppler signal was used to evaluate the performance of the above mentioned spectral methods and Gaussian noise was added to obtain a set of signals with various signal-to-noise ratios. Two different parameters were used to evaluate the performance of each method in terms of variability and accurate matching of the theoretical Doppler mean instantaneous frequency variation within the cardiac cycle. Results show that autoregressive modelling outperforms the other investigated spectral techniques for window lengths varying between 1 and 10 ms. Among the autoregressive algorithms implemented, it is shown that the maximum entropy method based on a block data processing technique gives the best results for a signal-to-noise ratio of 20 dB. However, at 10 and 0 dB, the Levinson-Durbin algorithm surpasses the performance of the maximum entropy method. It is expected that the intrinsic variance of the spectral methods can be an important source of error for the estimation of the turbulence intensity. The range of this error varies from 0.38% to 24% depending on the parameters of the spectral method and the signal-to-noise ratio. PMID:10505377

Sava, H; Durand, L G; Cloutier, G

1999-05-01

352

Short-Term Chromospheric Variability in alpha Tauri (K5 III): Results from IUE Time Series Observations  

NASA Technical Reports Server (NTRS)

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.

Cuntz, Manfred; Deeney, Bryan D.; Brown, Alexander; Stencel, Robert E.

1996-01-01

353

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

PubMed

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 T(2)* 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 T(1) is extracted, which is needed for quantification. Unlike T(2)*, which has been found to vary within a narrow range and does not require individual correction, T(1) is critically subject dependent (range, 100-350 ms). No soft-tissue suppression was used to preserve the signal-to-noise ratio of the short-T(2) 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/T(1) and 1/T(2)*) 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

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

2011-08-01

354

Revisiting Dialogues and Monologues  

ERIC Educational Resources Information Center

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…

Kvernbekk, Tone

2012-01-01

355

PTH revisited12  

Microsoft Academic Search

PTH revisited. Recent investigations of parathyroid hormone (PTH) have advanced our understanding of its circulating forms as well as its action. It is now clear that first-generation immunoradiometric assays of so-called intact “PTH” not only measured full-length PTH(1–84) but also recognized large PTH fragments lacking the amino-terminus. New, second generation assays detect only full-length PTH. Under diverse pathological settings, second

Peter A. Friedman

2004-01-01

356

Interpreting Short Gamma-Ray Burst Progenitor Kicks and Time Delays using the Host Galaxy-Dark Matter Halo Connection  

NASA Astrophysics Data System (ADS)

Nearly 20% of short gamma-ray bursts (sGRBs) have no observed host galaxies. Combining this finding with constraints on galaxies' dark matter halo potential wells gives strong limits on the natal kick velocity distribution for sGRB progenitors. For the best-fitting velocity distribution, one in five sGRB progenitors receives a natal kick above 150 km s-1, consistent with merging neutron star models but not with merging white dwarf binary models. This progenitor model constraint is robust to a wide variety of systematic uncertainties, including the sGRB progenitor time-delay model, the Swift redshift sensitivity, and the shape of the natal kick velocity distribution. We also use constraints on the galaxy-halo connection to determine the host halo and host galaxy demographics for sGRBs, which match extremely well with available data. Most sGRBs are expected to occur in halos near 1012 M ? and in galaxies near 5 × 1010 M ? (L *); unobserved faint and high-redshift host galaxies contribute a small minority of the observed hostless sGRB fraction. We find that sGRB redshift distributions and host galaxy stellar masses weakly constrain the progenitor time-delay model; the active versus passive fraction of sGRB host galaxies may offer a stronger constraint. Finally, we discuss how searches for gravitational wave optical counterparts in the local universe can reduce follow-up times using these findings.

Behroozi, Peter S.; Ramirez-Ruiz, Enrico; Fryer, Christopher L.

2014-09-01

357

Thermal inactivation of Pediococcus sp. in simulated apple cider during high-temperature short-time pasteurization.  

PubMed

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. PMID:12505457

Piyasena, P; McKellar, R C; Bartlett, F M

2003-01-26

358

Inherent Variability in Short-time Wind Turbine Statistics from Turbulence Structure in the Atmospheric Surface Layer  

NASA Astrophysics Data System (ADS)

Using large-eddy simulation (LES) of the neutral and moderately convective atmospheric boundary layers (NBL, MCBL), we analyze the impact of coherent turbulence structure of the atmospheric surface layer on the short-time statistics that are commonly collected from wind turbines. The incoming winds are conditionally sampled with a filtering and thresholding algorithm into high/low horizontal and vertical velocity fluctuation coherent events. The time scales of these events are ˜5 - 20 blade rotations and are roughly twice as long in the MCBL as the NBL. Horizontal velocity events are associated with greater variability in rotor power, lift and blade-bending moment than vertical velocity events. The variability in the industry standard 10 minute average for rotor power, sectional lift and wind velocity had a standard deviation of ˜ 5% relative to the ``infinite time'' statistics for the NBL and ˜10% for the MCBL. We conclude that turbulence structure associated with atmospheric stability state contributes considerable, quantifiable, variability to wind turbine statistics. Supported by NSF and DOE.

Lavely, Adam; Vijayakumar, Ganesh; Brasseur, James; Paterson, Eric; Kinzel, Michael

2011-11-01

359

Functional traits as indicators of fodder provision over a short time scale in species-rich grasslands  

PubMed Central

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:18974100

Ansquer, Pauline; Duru, Michel; Theau, Jean Pierre; Cruz, Pablo

2009-01-01

360

Deep inelastic neutron scattering from orthorhombic ordered HCl: Short-time proton dynamics and anomalous neutron cross sections  

SciTech Connect

Deep inelastic neutron scattering measurements from orthorhombic ordered HCl are presented and analyzed in order to clarify the problem of an anomalous deficit in the neutron-proton cross section found in previous experiments on various materials. A reliable model for the HCl short-time single-particle dynamics, including atomic vibrational anisotropies and deviations from the impulsive approximation, is set up. The model HCl response function is transformed into simulated time-of-flight spectra, taking carefully into account the effects of instrumental resolution and the filter absorption profile used for neutron energy analysis. Finally, the experimental values of the anomalous reduction factor for the neutron-proton cross section are extracted by comparing simulated and experimental data. Results show a 34% reduction of the H cross section, varying with the scattering angle in a range centered at 53 deg. In addition, the same approximate procedure used in earlier studies is also employed, providing results in reasonable agreement with the more rigorous ones, and confirming the substantial reliability of the past work on this subject.

Senesi, R.; Colognesi, D.; Pietropaolo, A.; Abdul-Redah, T. [Istituto Nazionale per la Fisica della Materia, Consiglio Nazionale delle Ricerche, UdR Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome (Italy); Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Via Madonna del Piano s.n.c., 50019 Sesto Fiorentino, FI (Italy); Istituto Nazionale per la Fisica della Materia, Consiglio Nazionale delle Ricerche, UdR Tor Vergata and Dipartimento di Fisica, Universita degli Studi di Roma-Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome (Italy); Physics Laboratory, University of Kent at Canterbury, Canterbury, Kent CT2 7NR (United Kingdom)

2005-08-01

361

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

SciTech Connect

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.

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

2006-01-01

362

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

NASA Astrophysics Data System (ADS)

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

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

363

Acquisition, storage, and review of safety data from a commercial system for high temperature, short time pasteurization.  

PubMed

A high temperature, short time (HTST) pasteurization system was equipped with electronic sensors to determine the temperature, pressure, flow rate, and position of the flow diversion valve. A computer for data acquisition was wired to the sensors to monitor and to record processing conditions related to public health. The processing conditions were stored in safety files on the hard drive of the computer, transferred weekly to a tape drive, and stored. The processing conditions of the HTST system were monitored for 270 d to determine the accuracy and reliability of the data acquisition system. The size of the HTST safety files ranged from 6.2 to 9.1 MB when the sensors were monitored every second. The file size was reduced to < 1.8 MB when the monitoring frequency was increased to every 5 s. To determine accuracy, the temperatures recorded by the data acquisition system were compared with the temperatures recorded by an electronic recorder controller. To determine reliability, changes in the position of the flow diversion valve were examined to identify process deviations and were compared with the event marker on circular charts. The review of the data file by the actual time method was an effective alternative to the electronic recorder controller for monitoring the completeness of data in the safety files. Off-line review to determine reliability required approximately 10 min/d of records. PMID:9493080

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

1998-01-01

364

Electrocardiogram Signal and Linear Time-Frequency Transforms  

NASA Astrophysics Data System (ADS)

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.

Krishna, B. T.

2014-12-01

365

Radiolytic Cryovolcanism Revisited  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

366

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

E-print Network

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

367

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

PubMed

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

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

2007-07-01

368

Interactions of Grazing History, Cattle Removal and Time since Rain Drive Divergent Short-Term Responses by Desert Biota  

PubMed Central

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 respond to grazing. PMID:23874635

Frank, Anke S. K.; Dickman, Chris R.; Wardle, Glenda M.; Greenville, Aaron C.

2013-01-01

369

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

NASA Technical Reports Server (NTRS)

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.

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

2014-01-01

370

Development of the short time exposure (STE) test: an in vitro eye irritation test using SIRC cells.  

PubMed

Using SIRC (rabbit corneal cell line) cells, we developed an alternative eye irritation test: the short time exposure (STE) test. This STE test is a cytotoxicity test using physiological saline or mineral oil as the test solvent. Evaluation exposure time is short (5 min), which is similar to actual exposure situations, and uses the cell viability (CV) at a constant concentration as the endpoint for irritation potential. First, in order to confirm the usefulness of this STE test in assessing eye irritation potential of chemicals, 51 raw materials were tested and the correlation between CV in the STE test and the eye irritation score in the Draize test was examined. For the undiluted raw materials tested in the Draize test, the 5% test concentration in the STE test gave irritation classes that correlated well with the irritation classes from the Draize test (accuracy: 89.6%). For those materials tested as a 10% solution in the Draize test, STE irritation classes with 0.05% test concentration corresponded well with the Draize irritation classes (accuracy: 80.0%). Next, using the cell viabilities at these two concentrations, the STE prediction model (PM) was developed. A score of 1 or 2 was given for the results from each tested concentration in the STE test and Draize test. The scores from each test were then summed to yield a 3-level (Rank 1: minimally irritant, Rank 2: moderate irritant, Rank 3: severe irritant) eye irritation potential classification. Rank classification in the STE test showed a good correlation mostly to that in the Draize test (irritation class correspondence rate: 70.2%, but after exclusion of data of alcoholic materials, the rate was 91.7%). In most cytotoxicity test, the cytotoxicity of acids and amines is generally underestimated due the use of medium as the solvent. This is the result of the buffering capacity of the media. On the other hand, the STE test could predict the eye irritation potential by evaluating the chemical with a 5% test concentration. Eleven water insoluble materials such as toluene, octanol, and hexanol could be evaluated by using mineral oil as test solvent in the STE test. The STE test demonstrated itself to be simple, promising, have great potential, be of value, and to be an easily standardized alternative eye irritation test. PMID:18248950

Takahashi, Yutaka; Koike, Mirei; Honda, Hiroshi; Ito, Yuichi; Sakaguchi, Hitoshi; Suzuki, Hiroyuki; Nishiyama, Naohiro

2008-04-01

371

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

PubMed

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

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

2014-08-01

372

On board short-time high temperature heat treatment of ballast water: a field trial under operational conditions.  

PubMed

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. PMID:18036619

Quilez-Badia, Gemma; McCollin, Tracy; Josefsen, Kjell D; Vourdachas, Anthony; Gill, Margaret E; Mesbahi, Ehsan; Frid, Chris L J

2008-01-01

373

Definition of the applicability domain of the Short Time Exposure (STE) test for predicting the eye irritation of chemicals.  

PubMed

The Short Time Exposure (STE) test is a simple and easy-to-perform in vitro eye irritation test, that uses the viability of SIRC cells (a rabbit corneal cell line) treated for five minutes as the endpoint. In this study, our goal was to define the applicability domain of the STE test, based on the results obtained with a set of 113 substances. To achieve this goal, chemicals were selected to represent both different chemical classes and different chemical properties, as well as to cover, in a balanced manner, the categories of eye irritation potential according to the Globally Harmonised System (GHS). Accuracy analysis indicated that the rates of false negatives for organic/inorganic salts (75.0%), hydrocarbons (33.3%) and alcohols (23.5%) were high. Many of the false negative results were for solid substances. It is noteworthy that no surfactant resulted in a false negative result in the STE test. Further examination of the physical property data and performance showed a significant improvement in the predictive accuracy, when substances with vapour pressures over 6kPa were excluded from the analyses. Our results indicate that several substances - i.e. certain solids such as salts, alcohols, hydrocarbons, and volatile substances with a vapour pressure over 6kPa - do not fall within the applicability domain of the STE test. Overall, we are encouraged by the performance and improved accuracy of the STE test. PMID:23781933

Hayashi, Kazuhiko; Abo, Takayuki; Nukada, Yuko; Sakaguchi, Hitoshi

2013-05-01

374

Intrinsic magnetic properties of BixCo2-xMnO4 spinels obtained by short-time etching  

NASA Astrophysics Data System (ADS)

We report the structural and magnetic properties of Co2MnO4, partially substituted by Bi at the octahedral site. Bismuth enhances ferromagnetism due to a decrease of the Co2+-Co2+ antiferromagnetic interactions and an increase of the Mn3+-Mn4+ exchanges. Spurious phases (magnetic and/or nonmagnetic oxides) can easily form because of the large differences between the ionic radii of Bi3+ and Co3+, hiding or altering the intrinsic physical properties of the main BixCo2-xMnO4 phase. An easy way to eliminate the secondary phases is using acid reagents. Short-time etching of Bi0.1Co1.9MnO4 using nitric acid was successfully used, keeping most of the properties of the initial compound, with no alteration of the crystallographic structure. Final stoichiometry was respected (˜Bi0.08Co1.82MnO4), meaning that the material after etching definitely contains bismuth elements in its structure and the observed properties are intrinsic to the oxide spinel. Additional experiments were performed as a function of the synthesis conditions, showing that an optimal pH value of 7 allowed the best magnetic response of the non-doped material.

dos Santos, M. E.; Lisboa-Filho, P. N.; Gouttefangeas, F.; Peña, O.

2013-08-01

375

Real-Time Imaging of DNA Damage in Yeast Cells Using Ultra-Short Near-Infrared Pulsed Laser Irradiation  

PubMed Central

Analysis of accumulation of repair and checkpoint proteins at repair sites in yeast nuclei has conventionally used chemical agents, ionizing radiation or induction of endonucleases to inflict localized damage. In addition to these methods, similar studies in mammalian cells have used laser irradiation, which has the advantage that damage is inflicted at a specific nuclear region and at a precise time, and this allows accurate kinetic analysis of protein accumulation at DNA damage sites. We show here that it is feasible to use short pulses of near-infrared laser irradiation to inflict DNA damage in subnuclear regions of yeast nuclei by multiphoton absorption. In conjunction with use of fluorescently-tagged proteins, this allows quantitative analysis of protein accumulation at damage sites within seconds of damage induction. PCNA accumulated at damage sites rapidly, such that maximum accumulation was seen approximately 50 s after damage, then levels declined linearly over 200–1000 s after irradiation. RPA accumulated with slower kinetics such that hardly any accumulation was detected within 60 s of irradiation, and levels subsequently increased linearly over the next 900 s, after which levels were approximately constant (up to ca. 2700 s) at the damage site. This approach complements existing methodologies to allow analysis of key damage sensors and chromatin modification changes occurring within seconds of damage inception. PMID:25409521

Guarino, Estrella; Cojoc, Gheorghe; García-Ulloa, Alfonso; Toli?, Iva M.; Kearsey, Stephen E.

2014-01-01

376

Application of attitude jitter detection based on short-time asynchronous images and compensation methods for Chinese mapping satellite-1.  

PubMed

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. PMID:25835898

Sun, Tao; Long, Hui; Liu, Bao-Cheng; Li, Ying

2015-01-26

377

The angular momentum of baryons and dark matter halos revisited  

Microsoft Academic Search

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

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

2011-01-01

378

Contribution of pluri-annual electrical time laps survey to the understanding of short and long term landslide dynamics  

NASA Astrophysics Data System (ADS)

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 resolution, we propose a clustering analysis on both apparent resistivity data and inverted data based on a hierarchical clustering algorithm which construct agglomerative clusters using the correlation coefficient between the different resistivity measurements. A special attention was paid to data filtering as the method needs a good signal to noise ratio to be conclusive. We also carefully chose the strategy for the inversion of the apparent resistivities in order to best accommodate gaps in the data (representing about 20 percent of the survey duration). Without making any assumption on the local geology, we were able to locate geological units displaying different behaviors. Comparatively, the method applied to inverted data will probably allow quantifying fluids circulation within the unstable slope. This late information is of major importance to the improvement of landslide modeling and will help to forecast landslide re-activation.

Levy, C.; Zerathe, S.; Lebourg, T.

2012-04-01

379

The sun compass revisited  

PubMed Central

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

Guilford, Tim; Taylor, Graham K.

2014-01-01

380

Improved short peptide identification using HILIC-MS/MS: retention time prediction model based on the impact of amino acid position in the peptide sequence.  

PubMed

Short peptides can have interesting beneficial effects but they are difficult to identify in complex mixtures. We developed a method to improve short peptide identification based on HILIC-MS/MS. The apparent hydrophilicity of peptides was determined as a function of amino acid position in the sequence. This allowed the differentiation of peptides with the same amino acid composition but with a different sequence (homologous peptides). A retention time prediction model was established using the hydrophilicity and peptide length of 153 di- to tetrapeptides. This model was proven to be reliable (R(2)=0.992), it was validated using statistical methods and a mixture of 14 synthetic peptides. A whey protein hydrolysate was analysed to assess the ability of the model to identify unknown peptides. In parallel to milk protein database and de novo searches, the retention time prediction model permitted reduction and ranking of potential short peptides, including homologous peptides, present in the hydrolysate. PMID:25466098

Le Maux, Solène; Nongonierma, Alice B; FitzGerald, Richard J

2015-04-15

381

Second-phase validation study of short time exposure test for assessment of eye irritation potency of chemicals.  

PubMed

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). PMID:23747838

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

382

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

PubMed Central

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

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

2014-01-01

383

A voxel-based investigation for MRI-only radiotherapy of the brain using ultra short echo times.  

PubMed

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 comparison. The mean dosimetric deviation for photons and protons compared to the CT was about 2% and highest in the gradient dose region of the brainstem. Both the threshold based method and the statistical regression methods showed the highest dosimetrical agreement.Generation of pCTs using statistical regression seems to be the most promising candidate for MRI-only RT of the brain. Further, the total amount of different tissues needs to be taken into account for dosimetric considerations regardless of their correct geometrical position. PMID:25393873

Edmund, Jens M; Kjer, Hans M; Van Leemput, Koen; Hansen, Rasmus H; Andersen, Jon A L; Andreasen, Daniel

2014-12-01

384

Large volume recycling of oceanic lithosphere over short time scales: geochemical constraints from the Caribbean Large Igneous Province  

NASA Astrophysics Data System (ADS)

Oceanic flood basalts are poorly understood, short-term expressions of highly increased heat flux and mass flow within the convecting mantle. The uniqueness of the Caribbean Large Igneous Province (CLIP, 92-74 Ma) with respect to other Cretaceous oceanic plateaus is its extensive sub-aerial exposures, providing an excellent basis to investigate the temporal and compositional relationships within a starting plume head. We present major element, trace element and initial Sr-Nd-Pb isotope composition of 40 extrusive rocks from the Caribbean Plateau, including onland sections in Costa Rica, Colombia and Curaçao as well as DSDP Sites in the Central Caribbean. Even though the lavas were erupted over an area of ˜3×10 6 km 2, the majority have strikingly uniform incompatible element patterns (La/Yb=0.96±0.16, n=64 out of 79 samples, 2?) and initial Nd-Pb isotopic compositions (e.g. 143Nd/ 144Nd in=0.51291±3, ?Ndi=7.3±0.6, 206Pb/ 204Pb in=18.86±0.12, n=54 out of 66, 2?). Lavas with endmember compositions have only been sampled at the DSDP Sites, Gorgona Island (Colombia) and the 65-60 Ma accreted Quepos and Osa igneous complexes (Costa Rica) of the subsequent hotspot track. Despite the relatively uniform composition of most lavas, linear correlations exist between isotope ratios and between isotope and highly incompatible trace element ratios. The Sr-Nd-Pb isotope and trace element signatures of the chemically enriched lavas are compatible with derivation from recycled oceanic crust, while the depleted lavas are derived from a highly residual source. This source could represent either oceanic lithospheric mantle left after ocean crust formation or gabbros with interlayered ultramafic cumulates of the lower oceanic crust. High 3He/ 4He in olivines of enriched picrites at Quepos are ˜12 times higher than the atmospheric ratio suggesting that the enriched component may have once resided in the lower mantle. Evaluation of the Sm-Nd and U-Pb isotope systematics on isochron diagrams suggests that the age of separation of enriched and depleted components from the depleted MORB source mantle could have been ?500 Ma before CLIP formation and interpreted to reflect the recycling time of the CLIP source. Mantle plume heads may provide a mechanism for transporting large volumes of possibly young recycled oceanic lithosphere residing in the lower mantle back into the shallow MORB source mantle.

Hauff, F.; Hoernle, K.; Tilton, G.; Graham, D. W.; Kerr, A. C.

2000-01-01

385

Unplanned Emergency Department Revisits within 72 Hours to a Secondary Teaching Referral Hospital in Taiwan  

Microsoft Academic Search

Background: When patients return to the emergency department (ED) shortly after being seen, it is generally assumed that their initial evaluation or treatment was inadequate. Objectives: The purpose of this study was to determine the rates and causes of revisits to the ED of a 710-bed secondary teaching referral hospital (Kuang Tien General Hospital), to identify areas for improvement, and

Chiu-Lung Wu; Fa-Tsai Wang; Yao-Chiu Chiang; Yuan-Fa Chiu; Teong-Giap Lin; Lian-Fong Fu; Tsung-Lung Tsai

2010-01-01

386

Revisiting Evidence for Modularity and Functional Equivalence across Verbal and Spatial Domains in Memory  

ERIC Educational Resources Information Center

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,…

Guerard, Katherine; Tremblay, Sebastien

2008-01-01

387

On the short time prediction of earthquakes in the Balkan Black Sea region based on geomagnetic field measurements and tide gravitational potential behavior  

Microsoft Academic Search

The paper is a first attempt for statistical estimation of method for a short time prediction of incoming earthquake in the Balkan and Black Sea region from January to June, 2002. The essence of the discovery is that the geomagnetic local \\

S. Cht. Mavrodiev

2002-01-01

388

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

E-print Network

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

Berlin,Technische Universität

389

Effect of the lattice oxygen mobility on the activity of Gd-doped ceria promoted with pt in syngas generation from methane at short contact times  

Microsoft Academic Search

Summary The activity of Pt\\/Ce1-xGdxO2-y samples in steam and dry reforming of methane at short contact times correlates with the lattice oxygen mobility. For the partial oxidation of methane (POM), the oxygen mobility should be optimized to prevent methane combustion.

Vladislav A. Sadykov; Yulia V. Frolova; Galina M. Alikina; Anton I. Lukashevich; Stylianos Neophytides

2005-01-01

390

Dynamic Solvation in Imidazolium-Based Ionic Liquids on Short Time Scales Lindsay Sanders Headley, Prasun Mukherjee, Jared L. Anderson, Rongfang Ding,  

E-print Network

Dynamic Solvation in Imidazolium-Based Ionic Liquids on Short Time Scales Lindsay Sanders Headley coumarin 153 in two imidazoles, six imidazolium- based ionic liquids, and several other solvents-10255) that initial solvation is dominated by the organic moiety of the ionic liquid, and they show

Song, Xueyu

391

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

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…

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

2012-01-01

392

Experiment of the observation of short-term time-variation of the hard X-ray region in Circinus X-1  

SciTech Connect

A balloon-borne experiment has been planned for the observation of the short-term time variation of the hard X-ray region in Cir X-1, a black hole candidate. This paper describes the details of the experiment, with emphasis on the instrumentation and the positioning of the balloon gondola.

Nakagawa, M.

1981-01-01

393

ESTIMATION OF A WHITE GAUSSIAN NOISE IN THE SHORT TIME FOURIER TRANSFORM BASED ON THE SPECTRAL KURTOSIS OF THE MINIMAL STATISTICS  

E-print Network

ESTIMATION OF A WHITE GAUSSIAN NOISE IN THE SHORT TIME FOURIER TRANSFORM BASED ON THE SPECTRAL signal is a signal to detect embedded in a white Gaussian noise, the variance of the noise Transform (STFT), whose squared modulus is the spectro- gram. The STFT of a white Gaussian noise

Paris-Sud XI, Université de

394

I will send the key shortly. I don't want to waste time going over the exam in class as  

E-print Network

2/12/2009 1 Exam · I will send the key shortly. · I don't want to waste time going over the exam questions ­ user expected a "magic pill" ­ dump the data in and out comes the answer. ­ How many horses

Allan, Vicki H.

395

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...

396

Timing in free-living rufous hummingbirds, Selasphorus rufus.  

PubMed

Animals organize their lives around circannual and circadian rhythms, but little is known of their use of much shorter intervals. In the laboratory, some animals can learn the specific duration (seconds or minutes) between periods of food access. It has been supposed that wild nectarivores, such as hummingbirds, might also learn short time intervals so as to avoid revisiting emptied flowers until the nectar has been replenished. We provided free-living, territorial rufous hummingbirds each with eight artificial flowers containing sucrose solution. Four flowers were refilled 10 min after the bird emptied them, and the other four were refilled 20 min after being emptied. Throughout the day, birds revisited the 10 min flowers significantly sooner than they revisited the 20 min flowers, and return visits to the flowers matched their refill schedules. Hummingbirds remembered the locations and timing of eight rewards, updating this information throughout the day. Not only is this the first time that this degree of timing ability has been shown in wild animals, but these hummingbirds also exhibit two of the fundamental aspects of episodic-like memory (where and when), the kind of memory for specific events often thought to be exclusive to humans. PMID:16527747

Henderson, Jonathan; Hurly, T Andrew; Bateson, Melissa; Healy, Susan D

2006-03-01

397

Pharmacy school survey standards revisited.  

PubMed

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

Mészáros, Károly; Barnett, Mitchell J; Lenth, Russell V; Knapp, Katherine K

2013-02-12

398

Spatial resolution in depth for time-resolved diffuse optical tomography using short source-detector separations  

PubMed Central

Diffuse optical tomography for medical applications can require probes with small dimensions involving short source-detector separations. Even though this configuration is seen at first as a constraint due to the challenge of depth sensitivity, we show here that it can potentially be an asset for spatial resolution in depth. By comparing two fiber optic probes on a test object, we first show with simulations that short source-detector separations improve the spatial resolution down to a limit depth. We then confirm these results in an experimental study with a state-of-the-art setup involving a fast-gated single-photon avalanche diode allowing maximum depth sensitivity. We conclude that short source-detector separations are an option to consider for the design of probes so as to improve image quality for diffuse optical tomography in reflectance. PMID:25657869

Puszka, Agathe; Di Sieno, Laura; Mora, Alberto Dalla; Pifferi, Antonio; Contini, Davide; Planat-Chrétien, Anne; Koenig, Anne; Boso, Gianluca; Tosi, Alberto; Hervé, Lionel; Dinten, Jean-Marc

2014-01-01

399

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

DOEpatents

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.

Veligdan, James T. (Manorville, NY)

1994-01-01

400

Revisiting the schism.  

PubMed

The schism between medicine and public health has deep historical roots. The Rockefeller Foundation's Clinical Epidemiology program, initiated in the late 1970s, was seen by Kerr White, its director, as the means to heal the schism. This article revisits the role that the Foundation played in creating that schism before reviewing post-World War II efforts on the part of both the Foundation and the World Health Organization to incorporate the teaching of preventive medicine in medical education curricula. White labeled these efforts as failures, but a closer look at the history raises questions concerning what evidence he used to make this judgment and whether clinical epidemiology has not instead widened the gap between cure and prevention. PMID:25626230

Litsios, Socrates

2014-01-01

401

Seasonal and short time gravity changes due to monsoonal rainfall in West Africa using a superconducting gravimeter  

NASA Astrophysics Data System (ADS)

A superconducting gravimeter (SG) has been installed since 2010 in Djougou, northern Benin, within the framework of the GHYRAF (Gravity and Hydrology in Africa) project. This site was first measured with a FG5 absolute gravimeter four times a year from 2008 to 2011. It was then decided to install a superconducting gravimeter in order to monitor in a continuous way the strong annual monsoon signal with both local and non-local hydrological contributions within the humid sudanian zone of West-Africa. The area is also part of the long-term observing system AMMA-Catch, and thus under intense hydro-meteorological monitoring (rain, soil moisture, water table level, evapotranspiration, etc…). We present here the results of the first two years relative gravity monitoring with SG-060 from GWR Instruments. FG5 absolute gravity data are used for calibration and drift estimate of the SG. As everywhere on the GGP (Global Geodynamics project) stations, the signal includes solid earth tides, ocean loading, polar motion, atmospheric pressure effects, drift and water storage changes (WSC). The barometric corrections are more complicated than for mid-latitude stations; indeed pressure effects are of major concern in the equatorial band, because they are governed by S1 and S2 thermal pressure waves. These waves dominate both the local Newtonian effect (an increase in local pressure decreases the gravity) and the smaller non-local loading effect (an increase in regional pressure decreases the gravity mostly by a subsidence effect of the elastic earth) because of their coherency at the regional scale. We focus here on two predominant frequencies: first the seasonal cycle where we compare the seasonal gravity signal left in the residuals after correction for solid Earth and ocean tides, atmosphere, polar motion and long term drift to Water Storage Changes (WSC) computed from observations in soil moisture (using neutronic measurements) and water table variations. Second we investigate the gravity signature of short term rainfall events. This includes both the rapid increase in gravity following a precipitation, and the slower decrease afterwards, related to evapotranspiration rates and underground water redistribution. In particular we will show the so-called 'shelter effect' which reduces the apparent rain-gravity admittance (in terms of µGal per mm of rain). We will try to derive a general model for our site from the analysis of numerous rain events during the summer monsoon.

Hector, Basile; Hinderer, Jacques; Séguis, Luc; Boy, Jean-Paul; Calvo, Marta; Descloitres, Marc; Rosat, Séverine; Riccardi, Umberto

2013-04-01

402

Design considerations for a high-power, short rise-time pulser for thick-transducer applications  

Microsoft Academic Search

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,

Paul M. Gammell; Gerald R. Harris

2002-01-01

403

ANALYSIS OF LIGHTNING FAULT DETECTION, LOCATION AND PROTECTION ON SHORT AND LONG TRANSMISSION LINES USING REAL TIME DIGITAL SIMULATION  

Microsoft Academic Search

The purpose of this paper is to present an analysis of lightning fault detection, location and protection using numeric distance relays applied in high voltage transmission lines, more specifically in the 500 kV transmission lines of CEMIG (Brazilian Energy Utility) between the Vespasiano 2 - Neves 1 (short line - 23.9 km) and Vespasiano 2 - Mesquita (long line -

André Luiz Pereira de Oliveira

404

Comparative performance of time-invariant, long-range and short-range forecasting models on the earthquake catalogue of Greece  

NASA Astrophysics Data System (ADS)

Time-invariant, long-range, and short-range forecasting models were fitted to the earthquake catalogue of Greece for magnitudes 4.0 and greater to optimize their ability to forecast events of magnitude 6.0 and greater in the period 1966-1980. The models considered were stationary spatially uniform and spatially varying Poisson models, a long-range forecasting model based on the precursory scale increase phenomenon with every earthquake regarded as a precursor according to scale, and epidemic type short-range forecasting models with spatially uniform and spatially varying spontaneous seismicity. Each of the models was then applied to the catalogue for 1981-2002, and their forecasting performance was compared using the log likelihood statistic. The long-range forecasting model performed substantially better than the time-invariant models, and the short-range forecasting models performed substantially better again. The results show that the information value to be gained from modeling temporal and spatial variation of earthquake occurrence rate, at both long and short range, is much greater than can be gained from modeling spatial variation alone.

Console, R.; Rhoades, D. A.; Murru, M.; Evison, F. F.; Papadimitriou, E. E.; Karakostas, V. G.

2006-09-01

405

26 CFR 1.6074-2 - Time for filing declarations by corporations in case of a short taxable year.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Time for filing declarations by corporations...CONTINUED) INCOME TAXES (CONTINUED) Time for Filing Returns and Other Documents § 1.6074-2 Time for filing declarations by...

2013-04-01

406

26 CFR 1.6074-2 - Time for filing declarations by corporations in case of a short taxable year.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Time for filing declarations by corporations...CONTINUED) INCOME TAXES (CONTINUED) Time for Filing Returns and Other Documents § 1.6074-2 Time for filing declarations by...

2011-04-01

407

26 CFR 1.6074-2 - Time for filing declarations by corporations in case of a short taxable year.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Time for filing declarations by corporations...CONTINUED) INCOME TAXES (CONTINUED) Time for Filing Returns and Other Documents § 1.6074-2 Time for filing declarations by...

2012-04-01

408

26 CFR 1.6074-2 - Time for filing declarations by corporations in case of a short taxable year.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Time for filing declarations by corporations...INCOME TAX (CONTINUED) INCOME TAXES Time for Filing Returns and Other Documents § 1.6074-2 Time for filing declarations by...

2010-04-01

409

26 CFR 1.6074-2 - Time for filing declarations by corporations in case of a short taxable year.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Time for filing declarations by corporations...CONTINUED) INCOME TAXES (CONTINUED) Time for Filing Returns and Other Documents § 1.6074-2 Time for filing declarations by...

2014-04-01

410

Continuous-time mean–variance portfolio selection with value-at-risk and no-shorting constraints  

Microsoft Academic Search

An investment problem is considered with dynamic mean–variance(M-V) portfolio criterion under discontinuous prices which follow jump–diffusion processes according to the actual prices of stocks and the normality and stability of the financial market. The short-selling of stocks is prohibited in this mathematical model. Then, the corresponding stochastic Hamilton–Jacobi–Bellman(HJB) equation of the problem is presented and the solution of the stochastic

Wei Yan

2011-01-01

411

Continuous-time mean–variance portfolio selection with value-at-risk and no-shorting constraints  

Microsoft Academic Search

An investment problem is considered with dynamic mean–variance(M-V) portfolio criterion under discontinuous prices which follow jump–diffusion processes according to the actual prices of stocks and the normality and stability of the financial market. The short-selling of stocks is prohibited in this mathematical model. Then, the corresponding stochastic Hamilton–Jacobi–Bellman(HJB) equation of the problem is presented and the solution of the stochastic

Wei Yan

2012-01-01

412

Detection of short pure-tone stimuli in the noctuid ear: what are temporal integration and integration time all about?  

Microsoft Academic Search

Temporal integration in the A1 acoustic receptor cell of noctuid moths (Lepidoptera: Noctuidae) was studied. This was done\\u000a by recording from the auditory nerve of Spodoptera littoralis and Noctua pronuba while stimulating with short-duration tone pulses. Consistent with previous experiments of the same kind, a decrease in threshold\\u000a was observed with increasing stimulus duration. These threshold improvements, however, were larger

J. Tougaard

1998-01-01

413

Design considerations for a high-power, short rise-time pulser for thick-transducer applications  

NASA Astrophysics Data System (ADS)

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.

Gammell, Paul M.; Harris, Gerald R.

2002-05-01

414

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

DOEpatents

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.

Veligdan, J.T.

1994-03-08

415

The bacterial nucleoid revisited.  

PubMed Central

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

Robinow, C; Kellenberger, E

1994-01-01

416

The Revolving Door Phenomenon Revisited: Time to Readmission in 17’415 Patients with 37’697 Hospitalisations at a German Psychiatric Hospital  

PubMed Central

Objective Despite the recurring nature of the disease process in many psychiatric patients, individual careers and time to readmission rarely have been analysed by statistical models that incorporate sequence and velocity of recurrent hospitalisations. This study aims at comparing four statistical models specifically designed for recurrent event history analysis and evaluating the potential impact of predictor variables from different sources (patient, treatment process, social environment). Method The so called Andersen-Gil counting process model, two variants of the conditional models of Prentice, Williams, and Peterson (gap time model, conditional probability model), and the so called frailty model were applied to a dataset of 17’415 patients observed during a 12 years period starting from 1996 and leading to 37’697 psychiatric hospitalisations. Potential prognostic factors stem from a standardized patient documentation form. Results Estimated regression coefficients over different models were highly similar, but the frailty model best represented the sequentiality of individual treatment careers and differing velocities of disease progression. It also avoided otherwise likely misinterpretations of the impact of gender, partnership, historical time and length of stay. A widespread notion of psychiatric diseases as inevitably chronic and worsening could be rejected. Time in community was found to increase over historical time for all patients. Most important protective factors beyond diagnosis were employment, partnership, and sheltered living situation. Risky conditions were urban living and a concurrent substance use disorder. Conclusion Prognostic factors for course of diseases should be determined only by statistical models capable of adequately incorporating the recurrent nature of psychiatric illnesses. PMID:24116059

Frick, Ulrich; Frick, Hannah; Langguth, Berthold; Landgrebe, Michael; Hübner-Liebermann, Bettina; Hajak, Göran

2013-01-01

417

Reply to comment on "A simple model for the short-time evolution of near-surface current and temperature profiles"  

E-print Network

This is our response to a comment by Walter Eifler on our paper `A simple model for the short-time evolution of near-surface current and temperature profiles' (arXiv:physics/0503186, accepted for publication in Deep-Sea Research II). Although Eifler raises genuine issues regarding our model's validity and applicability, we are nevertheless of the opinion that it is of value for the short-term evolution of the upper-ocean profiles of current and temperature. The fact that the effective eddy viscosity tends to infinity for infinite time under a steady wind stress may not be surprising. It can be interpreted as a vertical shift of the eddy viscosity profile and an increase in the size of the dominant turbulent eddies under the assumed conditions of small stratification and infinite water depth.

Jenkins, A D; Jenkins, Alastair D.; Ward, Brian

2005-01-01

418

Cretaceous eustasy revisited  

NASA Astrophysics Data System (ADS)

Eustatic sea-level changes of the Cretaceous are reevaluated based on a synthesis of global stratigraphic data. A new terminology for local/regional or relative sea-level changes (eurybatic shifts) is proposed to distinguish them from global (eustatic) sea-level changes, with the observation that all measures of sea-level change in any given location are eurybatic, even when they include a strong global signal. Solid-earth factors that influence inherited regional topography and thus modify physical measures of amplitude of the sea-level rises and falls locally are reviewed. One of these factors, dynamic topography (surface expression of mass flow in the upper mantle on land- and seascapes), is considered most pertinent in altering local measures of amplitude of sea-level events on third-order time scales (0.5-3.0 Myr). Insights gained from these models have led to the reconciliation of variance between amplitude estimates of eurybatic shifts in any given region and global measures of eustatic changes. Global estimates of third-order events can only be guesstimated at best by averaging the eurybatic data from widely distributed time-synchronous events. Revised curves for both long-term and short-term sea-level variations are presented for the Cretaceous Period. The curve representing the long-term envelope shows that average sea levels throughout the Cretaceous remained higher than the present day mean sea level (75-250 m above PDMSL). Sea level reached a trough in mid Valanginian (~ 75 m above PDMSL), followed by two high points, the first in early Barremian (~ 160-170 m above PDMSL) and the second, the highest peak of the Cretaceous, in earliest Turonian (~ 240-250 m above PDMSL). The curve also displays two ~ 20 Myr-long periods of relatively high and stable sea levels (Aptian through early Albian and Coniacian through Campanian). The short-term curve identifies 58 third-order eustatic events in the Cretaceous, most have been documented in several basins, while a smaller number are included provisionally as eustatic, awaiting confirmation. The amplitude of sea-level falls varies from a minimum of ~ 20 m to a maximum of just over 100 m and the duration varies between 0.5 and 3 Myr. The causes for these relatively rapid, and at times large amplitude, sea-level falls in the Cretaceous remain unresolved, although based mainly on oxygen-isotopic data, the presence of transient ice cover on Antarctica as the driver remains in vogue as an explanation. This idea has, however, suffered a recent setback following the discovery of pristine foraminiferal tests in the Turonian of Tanzania whose oxygen-isotopic values show little variation, implying absence of glacioeustasy at least in the Turonian. The prevalence of 4th-order (~ 400 Kyr) cyclicity through most of the Cretaceous (and elsewhere in the Paleozoic, Jurassic and Cenozoic) implies that the periodicity on this time scale, presumably driven by long-term orbital eccentricity, may be a fundamental feature of depositional sequences throughout the Phanerozoic.

Haq, Bilal U.

2014-02-01

419

Short term effects of temperature on risk of myocardial infarction in England and Wales: time series regression analysis of the Myocardial Ischaemia National Audit Project (MINAP) registry  

Microsoft Academic Search

Objective To examine the short term relation between ambient temperature and risk of myocardial infarction.Design Daily time series regression analysis.Setting 15 conurbations in England and Wales.Participants 84 010 hospital admissions for myocardial infarction recorded in the Myocardial Ischaemia National Audit Project during 2003-6 (median 57 events a day).Main outcome measures Change in risk of myocardial infarction associated with a 1°C

Krishnan Bhaskaran; Shakoor Hajat; Andy Haines; Emily Herrett; Paul Wilkinson; Liam Smeeth

2010-01-01

420

Two short questionnaires on leisure-time physical activity compared with serum lipids, anthropometric measurements and aerobic power in a suburban population from Oslo, Norway  

Microsoft Academic Search

The aim was to indirectly validate two short postal questionnaires measuring leisure-time physical activity (LPA) by comparing\\u000a the answers with serum lipids and anthropometric measurements. Methods All inhabitants aged 31–67 years in two suburban, multicultural areas of Oslo, Norway were invited to “Romsås in Motion”,\\u000a a community intervention survey, in 2000. Of those, 2950 participants (48%) met and were re-invited in

Sidsel Graff-Iversen; Sigmund Alfred Anderssen; Ingar Morten Holme; Anne Karen Jenum; Truls Raastad

2008-01-01

421

TRADES: A new software to derive orbital parameters from observed transit times and radial velocities. Revisiting Kepler-11 and Kepler-9  

NASA Astrophysics Data System (ADS)

Aims: With the purpose of determining the orbital parameters of exoplanetary systems from observational data, we have developed a software, named TRADES (TRAnsits and Dynamics of Exoplanetary Systems), to simultaneously fit observed radial velocities and transit times data. Methods: We implemented a dynamical simulator for N-body systems, which also fits the available data during the orbital integration and determines the best combination of the orbital parameters using grid search, ?2 minimization, genetic algorithms, particle swarm optimization, and bootstrap analysis. Results: To validate TRADES, we tested the code on a synthetic three-body system and on two real systems discovered by the Kepler mission: Kepler-9 and Kepler-11. These systems are good benchmarks to test multiple exoplanet systems showing transit time variations (TTVs) due to the gravitational interaction among planets. We have found that orbital parameters of Kepler-11 planets agree well with the values proposed in the discovery paper and with a a recent work from the same authors. We analyzed the first three quarters of Kepler-9 system and found parameters in partial agreement with discovery paper. Analyzing transit times (T0s), covering 12 quarters of Kepler data, that we have found a new best-fit solution. This solution outputs masses that are about 55% of the values proposed in the discovery paper; this leads to a reduced semi-amplitude of the radial velocities of about 12.80 ms-1.

Borsato, L.; Marzari, F.; Nascimbeni, V.; Piotto, G.; Granata, V.; Bedin, L. R.; Malavolta, L.

2014-11-01

422

Effect of time interval between prostaglandin F(2alpha) and GnRH treatments on occurrence of short estrous cycles in cyclic dairy heifers and cows.  

PubMed

Prostaglandin F(2alpha) (PGF(2alpha)) and GnRH treatments, when administered 24h apart during early diestrus, cause short estrous cycles in some dairy cows and heifers [J. Taponen, M. Kulcsar, T. Katila, L. Katai, G. Huszenicza, H. Rodriguez-Martinez, Short estrous cycles and estrous signs after premature ovulations induced with cloprostenol and gonadotropin-releasing hormone in cyclic dairy cows, Theriogenology 2002; 58, 1291-1302]. We investigated the effect of a time interval between PGF(2alpha) and GnRH administration on the appearance of short cycles. Estrus was induced in heifers with dexcloprostenol. A second luteolysis was induced similarly on day 7 after ovulation, and either 0 (T0) or 24h (T24) later an injection of GnRH (0.1mg of gonadorelin) was administered. We monitored ovarian activity with progesterone analyses from blood plasma samples and with ultrasonography. Fourteen cases (12 in T0 and 2 in T24) were excluded due to either incomplete luteolysis (2 cases) or unresponsiveness to GnRH (10 in T0 and 2 in T24). Short estrous cycles (7 to 8 d) were detected in 11/11 and 8/17 heifers in groups T0 and T24, respectively, with a significant difference in the incidence of short cycles (P<0.01). In Experiment 2, estrus was induced in cows on day 8 (D8, n=18), 9 (D9, n=5), or 10 (D10, n=3) with cloprostenol and gonadorelin administered simultaneously. Daily milk samples were collected for progesterone analysis until subsequent estrus was detected and ovarian ultrasound examinations were performed. Eight cases had to be excluded due to unresponsiveness to GnRH, leaving 18 cases eligible for the study. Short estrous cycles (7-12d) were detected in 14/18 cows. In conclusion, shortening the time interval between PGF(2alpha) and GnRH treatments increased the incidence of short estrous cycles and appeared to increase the proportion of females unresponsive to GnRH treatment. PMID:19111892

Rantala, M H; Katila, T; Taponen, J

2009-04-01

423

The linkages among hillslope-vegetation changes, elevation, and the timing of late-Quaternary fluvial-system aggradation in the Mojave Desert revisited  

NASA Astrophysics Data System (ADS)

Valley-floor-channel and alluvial-fan deposits and terraces in the southwestern US record multiple episodes of late-Quaternary fluvial-system aggradation and incision. Perhaps the most well-constrained of these episodes took place from the latest Pleistocene to the present in the Mojave Desert. One hypothesis for this episode - i.e., the paleovegetation-change hypothesis (PVCH) - posits that a reduction in hillslope vegetation cover associated with the transition from Pleistocene woodlands to Holocene desert scrub generated a pulse of sediment that triggered a primary phase of aggradation downstream, followed by channel incision, terrace abandonment, and initiation of a secondary phase of aggradation further downstream. A second hypothesis - i.e., the extreme-storm hypothesis - attributes episodes of aggradation and incision to changes in the frequency and/or intensity of extreme storms. In the past decade a growing number of studies has advocated the extreme-storm hypothesis and challenged the PVCH on the basis of inconsistencies in both timing and process. Here I show that in eight out of nine sites where the timing of fluvial-system aggradation in the Mojave Desert is reasonably well constrained, measured ages of primary aggradation are consistent with the predictions of the PVCH if the time-transgressive nature of paleovegetation changes with elevation is fully taken into account. I also present an alternative process model for PVCH that is more consistent with available data and produces sediment pulses primarily via an increase in drainage density (i.e., a transformation of hillslopes into low-order channels) rather than solely via an increase in sediment yield from hillslopes. This paper further documents the likely important role of changes in upland vegetation cover and drainage density in driving fluvial-system response during semiarid-to-arid climatic changes.

Pelletier, J. D.

2014-08-01

424

Searle's"Dualism Revisited"  

SciTech Connect

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.

P., Henry

2008-11-20

425

Revisiting caspases in sepsis  

PubMed Central

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

Aziz, M; Jacob, A; Wang, P

2014-01-01

426

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

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Does the Job Training Program provide part-time training...THE INTERIOR HUMAN SERVICES JOB PLACEMENT AND TRAINING PROGRAM Training Services § 26.30 Does the Job Training Program provide part-time...

2010-04-01

427

Kinetic theory of density fluctuations in a one-component monatomic fluid at equilibrium: A short time theory for the memory function  

NASA Astrophysics Data System (ADS)

A diagrammatic formulation of kinetic theory of fluctuations in equilibrium classical fluids is used to investigate the short time behaviour of the memory function for density fluctuations. We consider a model system, such as the Lennard-Jones potential, that contains both strongly repulsive forces and weaker attractive forces. We define a small parameter that is a measure of the, softness of the repulsive forces. The diagrams in the series for the memory function that are of lowest order in this small parameter for small times are identified and summed to get an expression for what we call the "short time approximation" (STA) for the memory function. The correlation function calculated using the STA describes the dynamics of the system as governed by a series of uncorrelated repulsive binary collisions. We evaluate the matrix elements of the memory function in the short time approximation by performing two-particle trajectory calculations. We use these matrix elements in the differential equations and solve for the time correlation functions. The results are compared to computer simulation data for a Lennard-Jones fluid. We calculate the correlation functions at a high density near the triple point density and at temperatures from the triple point temperature to just above the critical temperature. The correlation functions that we calculate are scattering functions, current correlation functions and the velocity autocorrelation function. We also calculate self-diffusion coefficients and the viscosity coefficients using the long time behavior of the correlation functions. The STA results are closer to the simulation results at high temperatures than at low temperatures, and at large wave vectors than at low wave vectors. The STA results are more accurate for self properties than for total properties. The self-diffusion coefficients and the viscosity coefficients can be understood on the basis of an Enskog theory for transport coefficients, modified for the case of continuous repulsive potentials with attractions. Understanding the predictions of the short time approximation to the memory function will be useful in the development of a comprehensive kinetic theory of dense fluids that will work for all times.

Ranganathan, Madhav V.

428

The "Mushroom Cloud" Demonstration Revisited  

ERIC Educational Resources Information Center

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…

Panzarasa, Guido; Sparnacci, Katia

2013-01-01

429

Internet Governance revisited: Think decentralization!  

E-print Network

Internet Governance revisited: Think decentralization! Brown-bag presentation given at the National Administration of the core technical resources of the Internet: ICANN: The mission... ,,preserving the public of the Internet" #12;unique identifiers basis for accurate routing of information (TCP/IP) IP-blocks managed

Schweik, Charles M.

430

Quantum Damped Harmonic Oscillator Revisited  

E-print Network

In this paper we revisit the quantum damped harmonic oscillator and construct an interesting approximate solution in the operator algebra level. Namely, we first give the general solution to the Lindblad form (equation) and next construct an approximate solution to the full equation by use of it. Our method is a milestone to construct the general solution.

Fujii, Kazuyuki

2007-01-01

431

Extended equal area criterion revisited  

Microsoft Academic Search

This paper reports on a case study conducted on the EHV French power system in order to revisit the extended equal area criterion and test its suitability as a fast transient stability indicator. The assumptions underlying the method are reexamined, causes liable to invalidate them are identified, and indices are devised to automatically circumvent them. The selection of candidate critical

X. Xue; L. Wehenkel; R. Belhomme; P. Rousseaux; M. Pavella; E. Euxibie; B. Heilbronn; J. F. Lesigne

1992-01-01

432

Revisiting the Mysterious Mpemba Effect  

Microsoft Academic Search

The effect of hot water freezing faster than cold water is mentioned in Greek literature. However, it came out as a scientific phenomenon during the last few decades and is known as Mpemba effect since 1969. But there is an inadequacy of explanation which was a challenge to the modern science. Hence, it is an important issue to revisit this

R. P. Gamage; S. R. D. Rosa

2008-01-01

433

The P600-as-P3 hypothesis revisited: single-trial analyses reveal that the late EEG positivity following linguistically deviant material is reaction time aligned.  

PubMed

The P600, a late positive ERP component following linguistically deviant stimuli, is commonly seen as indexing structural, high-level processes, e.g. of linguistic (re)analysis. It has also been identified with the P3 (P600-as-P3 hypothesis), which is thought to reflect a systemic neuromodulator release facilitating behavioural shifts and is usually response time aligned. We investigated single-trial alignment of the P600 to response, a critical prediction of the P600-as-P3 hypothesis. Participants heard sentences containing morphosyntactic and semantic violations and responded via a button press. The elicited P600 was perfectly response aligned, while an N400 following semantic deviations was stimulus aligned. This is, to our knowledge, the first single-trial analysis of language processing data using within-sentence behavioural responses as temporal covariates. Results support the P600-as-P3 perspective and thus constitute a step towards a neurophysiological grounding of language-related ERPs. PMID:25151545

Sassenhagen, Jona; Schlesewsky, Matthias; Bornkessel-Schlesewsky, Ina

2014-10-01

434

HPLC-NMR revisited: using time-slice high-performance liquid chromatography-solid-phase extraction-nuclear magnetic resonance with database-assisted dereplication.  

PubMed

Time-based trapping of chromatographically separated compounds onto solid-phase extraction (SPE) cartridges and subsequent elution to NMR tubes was done to emulate the function of HPLC-NMR for dereplication purposes. Sufficient mass sensitivity was obtained by use of a state-of-the-art HPLC-SPE-NMR system with a cryogenically cooled probe head, designed for 1.7 mm NMR tubes. The resulting (1)H NMR spectra (600 MHz) were evaluated against a database of previously acquired and prepared spectra. The in-house-developed matching algorithm, based on partitioning of the spectra and allowing for changes in the chemical shifts, is described. Two mixtures of natural products were used to test the approach: an extract of Carthamus oxyacantha (wild safflower), containing an array of spiro compounds, and an extract of the endophytic fungus Penicillum namyslowski, containing griseofulvin and analogues. The database matching of the resulting spectra positively identified expected compounds, while the number of false positives was few and easily recognized. PMID:23432092

Johansen, Kenneth T; Wubshet, Sileshi G; Nyberg, Nils T

2013-03-19

435

Development of a system for real-time measurements of metabolite transport in plants using short-lived positron-emitting radiotracers  

NASA Astrophysics Data System (ADS)

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 be introduced to plants as biologically active molecules such as 11CO2, N13O-3, 18F--[H2O], and H152O . Plants for these studies are grown in controlled-environment chambers at the Phytotron. The chambers offer an array of control for temperature, humidity, atmospheric CO2 concentration, and light intensity. Additionally, the Phytotron houses one large reach-in growth chamber that is dedicated to this project for radioisotope labeling measurements. There are several important properties of short-lived positron-emitting radio-tracers that make them well suited for use in investigating metabolite transport in plants. First, because the molecular mass of a radioisotope-tagged compound is only minutely different from the corresponding stable compound, radiotracer substances should be metabolized and transported in plants the same as their non-radioactive counterparts. Second, because the relatively high energy gamma rays emitted from electron-positron annihilation are attenuated very little by plant tissue, the real-time distribution of a radiotracer can be measured in vivo in plants. Finally, the short radioactive half-lives of these isotopes allow for repeat measurements on the same plant in a short period of time. For example, in studies of short-term environmental changes on plant metabolite dynamics, a single plant can be labeled multiple times to measure its responses to different, environmental conditions. Also, different short-lived radiotracers can be applied to the same plant over a short period of time to investigate the transport and allocation of various metabolites. This newly developed system provides the capabilities for production of 11CO2 at TUNL, transfer of the 11CO 2 gas from the target area at TUNL to a radiation-shielded cryogenic trap at the Phytotron, labeling of photoassimilates with 11C, and in vivo gamma-ray detection for real-time measurements of the radiotracer distribution in small plants. The experimental techniques and instrumentation that enabled the quantitative biological studies reported in this thesis were developed through a

Kiser, Matthew R.

436

2648 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 23, NO. 6, NOVEMBER 2008 The Short-Time-Scale Transient Processes in  

E-print Network

-Time-Scale Transient Processes in High-Voltage and High-Power Isolated Bidirectional DC­DC Converters Hua Bai, Chunting% to the primary winding of the high-frequency transformer. The voltage of the secondary wind- ing has a finite-time-scale transient processes in an isolated bidirectional dc­dc converter with phase- shift control. The deadband

Mi, Chunting "Chris"

437

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

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Does the Job Training Program provide part-time training...DEPARTMENT OF THE INTERIOR HUMAN SERVICES JOB PLACEMENT AND TRAINING PROGRAM Training Services § 26.30 Does the Job Training Program provide part-time...

2013-04-01

438

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

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Does the Job Training Program provide part-time training...DEPARTMENT OF THE INTERIOR HUMAN SERVICES JOB PLACEMENT AND TRAINING PROGRAM Training Services § 26.30 Does the Job Training Program provide part-time...

2014-04-01

439

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

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Does the Job Training Program provide part-time training...DEPARTMENT OF THE INTERIOR HUMAN SERVICES JOB PLACEMENT AND TRAINING PROGRAM Training Services § 26.30 Does the Job Training Program provide part-time...

2011-04-01

440

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

Code of Federal Regulations, 2012 CFR

...2012-04-01 2011-04-01 true Does the Job Training Program provide part-time training...DEPARTMENT OF THE INTERIOR HUMAN SERVICES JOB PLACEMENT AND TRAINING PROGRAM Training Services § 26.30 Does the Job Training Program provide part-time...

2012-04-01

441

Oxidative phosphorylation revisited.  

PubMed

The fundamentals of oxidative phosphorylation and photophosphorylation are revisited. New experimental data on the involvement of succinate and malate anions respectively in oxidative phosphorylation and photophosphorylation are presented. These new data offer a novel molecular mechanistic explanation for the energy coupling and ATP synthesis carried out in mitochondria and chloroplast thylakoids. The mechanism does not suffer from the flaws in Mitchell's chemiosmotic theory that have been pointed out in many studies since its first appearance 50 years ago, when it was hailed as a ground-breaking mechanistic explanation of what is perhaps the most important process in cellular energetics. The new findings fit very well with the predictions of Nath's torsional mechanism of energy transduction