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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

Electrically short dipoles with a nonlinear load, a revisited analysis  

Microsoft Academic Search

We reexamine the characteristics of electrically short dipoles with nonlinear loads and, specifically, the early work of Motohisa Kanda (1980, 1983). Although this topic has been examined in great detail in the past, some inconsistencies between numerical and analytical results are apparent, and these have not been previously addressed. We show that these inconsistencies were due to only periodic sampling

John M. Ladbury; Dennis G. Camell

2002-01-01

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

The SDC TimeSharing System revisited  

Microsoft Academic Search

In the light of accelerating interest, it seems worthwhile to review both the current status of TSS and some of the predictions made three years ago. Our review will include a brief overview of system changes, a discussion in some depth of resource allocation (which now appears to be the critical factor in general-purpose time-sharing systems), and some conclusions regarding

Jules I. Schwartz; Clark Weissman

1967-01-01

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

PubMed Central

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

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

2014-01-01

7

Girl Number 20 Revisited: Feminist Literacies in New Hard Times  

ERIC Educational Resources Information Center

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

Gonick, Marnina

2007-01-01

8

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

9

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

10

Particle creation in a time-dependent electric field revisited  

SciTech Connect

We adopt the general formalism for analyzing evolution of gaussian states of quantized fields in time-dependent backgrounds in the Schrodinger picture (presented in detail in Mahajan and Padmanabhan [G. Mahajan, T. Padmanabhan, Gen. Rel. Grav. 40 (2008) 661]) to study the example of a spatially uniform electric field background (in a time-dependent gauge) which is kept turned on for a finite duration of time. In particular, we study the time-dependent particle content, defined in terms of the concept of instantaneous eigenstates, and describe how it captures the time evolution of the quantized field modes. The actual particle creation process occurs over a relatively short interval in time, and the particle content saturates rather quickly. We also compare the power spectrum of the field modes, computed in the asymptotic limit, with the corresponding situation in a cosmological de Sitter background. Particle creation under the influence of a spiked electric field localized in time, as a particular limiting case of the above general model, is also considered.

Mahajan, Gaurang [IUCAA, Post Bag 4, Ganeshkhind, Pune 411 007 (India)], E-mail: gaurang@iucaa.ernet.in

2009-02-15

11

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

12

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

13

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

14

THE SPACE-TIME CUBE REVISITED FROM A GEOVISUALIZATION PERSPECTIVE  

Microsoft Academic Search

At the end of the sixties Hägerstrand introduced a space-time model which included features such as a Space-Time- Path, and a Space-Time-Prism. His model is often seen as the start of the time-geography studies. Throughout the years his model has been applied and improved to understand our movements through space. Problems studied can be found in different fields of geography,

M. Kraak

15

``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

16

Short-term travel time prediction  

Microsoft Academic Search

Effective prediction of travel times is central to many advanced traveler information and transportation management systems. In this paper we propose a method to predict freeway travel times using a linear model in which the coefficients vary as smooth functions of the departure time. The method is straightforward to implement, computationally efficient and applicable to widely available freeway sensor data.We

Xiaoyan Zhang; John A. Rice

2003-01-01

17

Primate molar crown formation times and life history evolution revisited.  

PubMed

Comparative studies have convincingly demonstrated that the pattern and timing of tooth emergence are highly correlated with life-history variables and brain size. Conversely, a firm relationship between molar formation time and life-history variables has not yet been established. It seems counterintuitive that one aspect of dental development should be correlated with life-history variables, whereas the other should not. In order to shed light on this apparent discrepancy this study analyzed all data on primate molar crown formations available in the published literature in relation to life-history variables, brain size, and female body mass. Crown formation times were found to be particularly highly correlated with both female body mass and brain size. Species that depart from the overall brain/body allometry by being relatively large-bodied, e.g., Gorilla gorilla and later Theropithecus oswaldi, also have shorter molar crown formation times than expected. The reverse is not found for species that depart from the overall brain/body allometry due to their larger brains, i.e., Homo sapiens. This finding is interpreted within an evolutionary and ecological framework. Specifically, by focusing on ecological commonalities, a scenario is proposed which may allow predictions to be made about the evolutionary history of other extinct primates also. If confirmed in future studies, crown formation time may again become a powerful tool in evolutionary enquiry. PMID:11748692

Macho, G A

2001-12-01

18

Managing high IC yields with short cycle times  

Microsoft Academic Search

High IC yields are the key to low product costs, essential for profitable pursuit of high volume GaAs IC markets for consumer applications. Short product development cycle times are essential for getting entry into such markets. Technology has been moving at a fast pace and product life cycles are getting shorter. Short development cycle times are needed not only to

S. Khetan; P. Fowler

1995-01-01

19

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

20

Numerical solutions to the time-dependent Bloch equations revisited.  

PubMed

The purpose of this study was to demonstrate a simple and fast method for solving the time-dependent Bloch equations. First, the time-dependent Bloch equations were reduced to a homogeneous linear differential equation, and then a simple equation was derived to solve it using a matrix operation. The validity of this method was investigated by comparing with the analytical solutions in the case of constant radiofrequency irradiation. There was a good agreement between them, indicating the validity of this method. As a further example, this method was applied to the time-dependent Bloch equations in the two-pool exchange model for chemical exchange saturation transfer (CEST) or amide proton transfer (APT) magnetic resonance imaging (MRI), and the Z-spectra and asymmetry spectra were calculated from their solutions. They were also calculated using the fourth/fifth-order Runge-Kutta-Fehlberg (RKF) method for comparison. There was also a good agreement between them, and this method was much faster than the RKF method. In conclusion, this method will be useful for analyzing the complex CEST or APT contrast mechanism and/or investigating the optimal conditions for CEST or APT MRI. PMID:20832224

Murase, Kenya; Tanki, Nobuyoshi

2011-01-01

21

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

22

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

23

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

24

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

25

Short-time quantum dynamics of sharp boundaries potentials  

NASA Astrophysics Data System (ADS)

Despite the high prevalence of singular potential in general, and rectangular potentials in particular, in applied scattering models, to date little is known about their short time effects. The reason is that singular potentials cause a mixture of complicated local as well as non-local effects. The object of this work is to derive a generic method to calculate analytically the short-time impact of any singular potential. In this paper it is shown that the scattering of a smooth wavefunction on a singular potential is totally equivalent, in the short-time regime, to the free propagation of a singular wavefunction. However, the latter problem was totally addressed analytically in Ref. [7]. Therefore, this equivalency can be utilized in solving analytically the short time dynamics of any smooth wavefunction at the presence of a singular potentials. In particular, with this method the short-time dynamics of any problem where a sharp boundaries potential (e.g., a rectangular barrier) is turned on instantaneously can easily be solved analytically.

Granot, Er'el; Marchewka, Avi

2015-02-01

26

Koolau Revisited: Vertical, Short-Scale Heterogeneities in the Hawaiian Plume  

NASA Astrophysics Data System (ADS)

The subaerial Makapuu stage lavas on the Koolau volcano define the isotopically enriched endmember of the Hawaiian lavas. Their compositions are central to the debate for the presence of recycled oceanic crust and the scales of heterogeneity in the Hawaiian plume. Despite their importance, however, relatively few isotope analyses exist. Here we report new high precision isotope data (Hf-Nd-Sr-Pb) and major / trace element compositions on newly collected samples from the Makapuu Head, Koolau. The new data extends to more unradiogenic isotopic compositions (?Nd= -1.3 - 3.0) than previously reported in Hawaiian lavas. In ?Hf - ?Nd space the Makapuu lavas define a shallower slope (0.75, r2 = 0.92) than all other Hawaiian lavas, while in Sr-Nd isotope space they define the steepest slope. On a 208Pb/204Pb vs. ?Nd plot, these lavas define a well correlated negative array that is best explained by the presence of a depleted component (low 208Pb/204Pb - high ?Nd) in the Makapuu source, similar to the isotopic characteristics of pyroxenite xenoliths and rejuvenated stage lavas from the Oahu and Kaula island. When plotted on any combination of 3-isotope systems (3D plots) the Makapuu and the stratigraphically lower KSDP lavas, show well defined but non-intersecting binary arrays. This feature cannot be explained by any two or three- component mixing, and requires that the plume source changed significantly and abruptly during the shield stage volcanism at Koolau. A reexamination of available high precision isotope data from other Hawaiian volcanoes further shows that each shield volcano defines a unique linear array (implying binary mixing) in all 3D isotope plot combinations that involve Hf-Nd-Sr-Pb isotopes. Note that, in general, there is very little overlap between the individual arrays. This requires that only a unique set of two end members, responsible for the isotopic variability of each volcano, is available during the eruption of that particular volcano. This observation is consistent with vertical heterogeneity within the Hawaiian plume. If vertical streaks are present within the upwelling plume (i.e. 'spaghetti' model), then the tight binary arrays defined by each volcano require that the compositions of the "streaks" are relatively constant but only present during the life cycle of each shield volcano (~500 ky). The "streaks" must have a finite length (i.e. short 'spaghetti', perhaps 'penne') in order to account for the volcano-to-volcano variability. While the concentrically zoned plume or the asymmetrically bilateral plume models are consistent with some large-scale lateral features of the Hawaiian plume (e.g. Loa - Kea trends) our data suggests that there is also considerable vertical heterogeneity within the Hawaiian plume.

Bizimis, M.; Salters, V. J.; Huang, S.

2008-12-01

27

Heart Knowledge A short time after being diagnosed with  

E-print Network

Heart Knowledge A short time after being diagnosed with cancer in December of 2005 I was having healing." "Listen with your heart," he said. He insisted I put my full faith in my oncologist, my surgeon that I needed to attend to my "inner healing and heart knowledge." What did Cliff mean by "heart

O'Laughlin, Jay

28

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

29

Rules extraction in short memory time series using genetic algorithms  

NASA Astrophysics Data System (ADS)

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

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

2001-04-01

30

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

31

Debonding mechanisms of soft materials at short contact times.  

PubMed

A carefully controlled, custom-built adhesion testing device was developed which allows a precise, short dwell time on the order of milliseconds to be applied during a contact adhesion experiment. The dwell time dependence of the adhesive strength of crosslinked poly(dimethylsiloxane) (PDMS) in contact with glass and uncrosslinked styrene butadiene rubber (SBR) in contact with glass and with itself was tested with a spherical probe in a confined Johnson-Kendall-Roberts (JKR) geometry. Analysis of the contact images revealed several unique separation mechanisms which are dependent on dwell time and interfacial properties. PDMS-glass interfaces show essentially no dependence of adhesion on the dwell time while the adhesive strength and separation mechanisms of SBR interfaces are shown to vary drastically for dwell times ranging from 40 to 10,000 ms. This influence of dwell time is particularly pronounced for polymer-polymer (SBR-SBR) interfaces. Observations of cavitation due to trapped air pockets in the center of the contact at very short contact times illustrate a transition between a defect-controlled debonding and an interface-controlled debonding which has not been previously reported. PMID:25127556

Davis, Chelsea S; Lemoine, Florian; Darnige, Thierry; Martina, David; Creton, Costantino; Lindner, Anke

2014-09-01

32

Characterization of short-time dealumined HZSM-5 zeolites  

Microsoft Academic Search

Temperature-programmed desorption (TPD) of water was applied to characterize short-time dealuminated HZSM-5 zeolites. Using\\u000a a regularization method, distribution functions of the effective desorption energy of water were calculated. The results clearly\\u000a show that during dealumination a new adsorption site is formed which can be attributed to non-framework or transient aluminium\\u000a species. The highest concentration of these sites was observed for

Rita Rosmarie Sattler; W.-D. Einicke; B. Hunger

2004-01-01

33

Computing short-time aircraft maneuvers using direct methods  

Microsoft Academic Search

This paper analyzes the applicability of direct methods to design optimal short-term spatial maneuvers for an unmanned vehicle\\u000a in a faster than real-time scale. It starts by introducing different basic control schemes, which employ online trajectory\\u000a generation. Next, it presents and analyzes the results obtained through two recently developed direct transcription (collocation)\\u000a methods: the Gauss pseudospec-tral method and the Legendre-Gauss-Lobatto

G. Basset; Y. Xu; O. A. Yakimenko

2010-01-01

34

Time-dependence in short-lived volcanic eruption plumes  

NASA Astrophysics Data System (ADS)

Establishing relationships between source conditions and plume evolution is critical for developing accurate, predictive models of volcanic plumes. Such relationships have been derived and successfully applied to field cases for long-duration eruptions with approximately constant source conditions. Similarly useful relationships exist for instantaneous releases. However, equivalent relationships have yet to be developed for time-varying and finite source conditions that drive many short-lived volcanic plumes, despite the fact that such eruptions are frequent in nature. Short-lived plumes have been observed and documented using UV, visible, and IR imaging techniques, as well as satellite and radar measurements. However, the source conditions which generate these plumes are difficult to constrain in the field. Thus, a laboratory investigation of jets and plumes generated by short-duration time-dependent sources was undertaken. Experiments were designed specifically to examine the role of time-dependent source conditions in controlling overall morphology, flow front velocity as a function of time, internal velocity and eddy structure, and entrainment characteristics. In the experimental work presented here, neutrally-buoyant turbulent jets were generated by injecting pressurized water into a tank of still water. Velocity and discharge rate with time were Gaussian-like with durations shorter than jet rise times. Flows had vent Reynolds numbers from 103 to 105 and were documented using flow visualization and particle image velocimetry. Two different flow patterns were observed: isolated vortex rings that separated from a trailing jet and head vortices connected to a trailing stem. The latter was favored as both the vent Reynolds number and the total ejected volume increased. These flows had three main phases of development - an injection phase which occurred while the source was 'on', a transition phase immediately following injection termination, and a final phase during which the flow continued to propagate although the injection had ended. The injection phase was further subdivided into two distinct sub-phases, corresponding to acceleration and deceleration at the vent. Scaling of the results indicate that individual characteristic velocities describe each of the acceleration, deceleration, and transition phases, whereas the final phase behaves like an instantaneous release of momentum, termed a puff. As such, time-dependent source conditions appear to have dominant first-order effects on flow evolution during the injection and transition phases but have little control over the dynamics during the final phase, when instead the total volume injected dominates the dynamics. These results have a number of implications for interpreting dynamics from observations of short-lived volcanic plumes. For example, estimates of vent fluxes from plume observations should be restricted to early 'source on' phases, while later stages of development should provide information about total volume erupted.

Chojnicki, K. N.; Clarke, A. B.; Phillips, J. C.; Adrian, R. J.

2011-12-01

35

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

36

Evaluation of scaling invariance embedded in short time series.  

PubMed

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 [Formula: see text]. Calculations with specified Hurst exponent values of [Formula: see text] 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 ([Formula: see text]) and sharp confidential interval (standard deviation [Formula: see text]). 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

37

Non-24-Hour Disorder in Blind Individuals Revisited: Variability and the Influence of Environmental Time Cues  

PubMed Central

Study Objectives: To assess the interindividual and intraindividual variability in the circadian rhythms of blind individuals with non-24-h disorder and to quantify the influence of environmental time cues in blind subjects lacking entrainment (non-24-h individuals or N-24s). Design: An observational study of 21 N-24s (11 females and 10 males, age 9-78 years) who kept a sleep/wake schedule of their choosing. Circadian phase was determined using the melatonin onset (MO) from plasma or saliva samples that were collected every 2 weeks. Melatonin concentrations were measured by radioimmunoassay. A total of 469 MO assessments were conducted over 5,536 days of study. The rate of drift of circadian phase was calculated using a series of MOs (total number of hours the MO drifted divided by the total number of days studied). Stability of the rest/activity rhythm was calculated using chi-squared periodogram analysis of wrist actigraphy data in 19 subjects. Setting: Academic medical center. Participants: Paid volunteers. Interventions: N/A. Measurements and Results: Subjects lacked entrainment such that circadian phase drifted an average (± standard deviation) of 0.39 ± 0.29 h later per day; however, there was notable intersubject and intrasubject variability in the rate of drift including relative coordination and periods of transient entrainment during which there was little to no drift in the circadian phase. A regular, reproducible, and significant oscillation in the rate of drift was detected in 14 of the 21 subjects. A significant non-24-h rest/activity rhythm was detected in 18 of 19 subjects. There was a strong correlation (r = 0.793, P = 0.0001) between the non-24-h rest/activity rhythm and the rate of drift of the circadian phase. Conclusions: Most N-24s are influenced by unidentified environmental time cues and the non-entrained biological clock in such N-24s is reflected in their rest/activity rhythms. These findings may have diagnostic and treatment implications: this disorder might be diagnosed with actigraphy alone, relative coordination and transient entrainment may result in misdiagnosis and responsiveness to environmental time cues may influence treatment success with oral melatonin. Citation: Emens JS; Laurie AL; Songer JB; Lewy AJ. Non-24-hour disorder in blind individuals revisited: variability and the influence of environmental time cues. SLEEP 2013;36(7):1091-1100. PMID:23814347

Emens, Jonathan S.; Laurie, Amber L.; Songer, Jeannie B.; Lewy, Alfred J.

2013-01-01

38

Granular impact dynamics: Fluctuations at short time-scales  

NASA Astrophysics Data System (ADS)

Several recent studies on granular impact have used a macroscopic force law which describes the slow (mean) dynamics. However, these force-law models must be modified to capture large fluctuations at short time-scales. Here, we discuss granular impact experiments using photoelastic particles, where high-speed video captures both the intruder dynamics and the local granular force response. We show how to systematically separate the fluctuations from the mean dynamics. We also show that these fluctuations are multiplicative with the mean force, and otherwise decoupled from the dynamics. These observations are instructive in connecting to microscopic processes which generate the fluctuations.

Clark, Abram H.; Kondic, Lou; Behringer, R. P.

2013-06-01

39

Short-time-interaction quantum measurement through an incoherent mediator  

SciTech Connect

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

Casanova, J.; Romero, G.; Lizuain, I.; Muga, J. G. [Departamento de Quimica Fisica, Universidad del Pais Vasco-Euskal Herriko Unibertsitatea, Apdo. 644, E-48080 Bilbao (Spain); Retamal, J. C. [Departamento de Fisica, Universidad de Santiago de Chile, USACH, Casilla 307, Santiago 2 (Chile); Roos, C. F. [Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, Otto-Hittmair-Platz 1, A-6020 Innsbruck (Austria); Institut fuer Experimentalphysik, Universitaet Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria); Solano, E. [Departamento de Quimica Fisica, Universidad del Pais Vasco-Euskal Herriko Unibertsitatea, Apdo. 644, E-48080 Bilbao (Spain); IKERBASQUE, Basque Foundation for Science, Alameda Urquijo 36, E-48011 Bilbao (Spain)

2010-06-15

40

Short and long time drop dynamics on lubricated substrates  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

41

Variations in solar Lyman alpha irradiance on short time scales  

NASA Technical Reports Server (NTRS)

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

Pap, J. M.

1992-01-01

42

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

PubMed Central

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

Sun, Zhigang; Yang, Weitao

2011-01-01

43

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

PubMed

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

Samiee, Kaveh; Kovacs, Peter; Gabbouj, Moncef

2015-02-01

44

Short-Time Optical Fiber Thermal Conductivity Sensor  

NASA Astrophysics Data System (ADS)

Thermal conductivities of liquids have been determined by using a variation of the transient hot-wire technique. A short segment of one arm of a fiber-optic Mach-Zehnder interferometer is coated with a thin layer of gold. This gold layer is heated resistively with a 1 msec current pulse producing a temperature change of only tenths of a degree. The magnitude of this temperature change (determined by the phase change in the interferometer) can be used to calculate the thermal conductivity of the medium in which the fiber is immersed. The conventional transient hot-wire thermal conductivity technique employs a much larger temperature rise and requires numerous correction terms. Results obtained in aqueous ethylene glycol solutions are reported.

Davis, J. P.; Samouris, A.; Bobb, L. C.; Larson, D. C.

1989-02-01

45

Evidence for short cooling time in the Io plasma torus  

Microsoft Academic Search

We present empirical evidence for a radiative cooling time for the Io plasma torus that is about a factor of ten less than presently accepted values. We show that brightness fluctuations of the torus in the extreme ultraviolet (EUV) at one ansa are uncorrelated with the brightness at the other ansa displaced in time by five hours, either later or

M. Volwerk; M. E. Brown; A. J. Dessler; B. R. Sandel

1997-01-01

46

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

NASA Astrophysics Data System (ADS)

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

Fan, Qinru; Ren, Wen-hua

2013-07-01

47

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

PubMed Central

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

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

2011-01-01

48

Estimating Mean First Passage Time of Biased Random Walks with Short Relaxation Time on Complex Networks  

PubMed Central

Biased random walk has been studied extensively over the past decade especially in the transport and communication networks communities. The mean first passage time (MFPT) of a biased random walk is an important performance indicator in those domains. While the fundamental matrix approach gives precise solution to MFPT, the computation is expensive and the solution lacks interpretability. Other approaches based on the Mean Field Theory relate MFPT to the node degree alone. However, nodes with the same degree may have very different local weight distribution, which may result in vastly different MFPT. We derive an approximate bound to the MFPT of biased random walk with short relaxation time on complex network where the biases are controlled by arbitrarily assigned node weights. We show that the MFPT of a node in this general case is closely related to not only its node degree, but also its local weight distribution. The MFPTs obtained from computer simulations also agree with the new theoretical analysis. Our result enables fast estimation of MFPT, which is useful especially to differentiate between nodes that have very different local node weight distribution even though they share the same node degrees. PMID:24699325

Lee, Zhuo Qi; Hsu, Wen-Jing; Lin, Miao

2014-01-01

49

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

E-print Network

A short introduction to viscosity solutions and the large time behavior of solutions of Hamilton to the theory of viscosity solutions of first- order partial differential equations and a review on the optimal introduction to viscosity solutions of first-order partial differential equations (PDE for short) and to review

Ishii, Hitoshi

50

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

51

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

52

Short-time forecasting of the system magnetosheath -magnetosphere  

NASA Astrophysics Data System (ADS)

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

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

53

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

54

Bayesian Forecasting Methods for Short Time Series by Enrique de Alba and Manuel Mendoza  

E-print Network

1 Bayesian Forecasting Methods for Short Time Series by Enrique de Alba and Manuel Mendoza Preview This article by Enrique de Alba and Manuel Mendoza extends Foresight's coverage of approaches to forecasting

Mendoza Ramírez, Manuel

55

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

56

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

57

A detection of short-period terms in Universal Time of Chinese Joint System.  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to detect the tidal short-period terms in Universal Time (UT) of Chinese Joint System (CJS). A reduction of the relevant data in "Annual Report of Chinese Time Service" and "Annual Report of BIH" gives a consecutive series of UT of CJS at the interval from 1967 to 1978. Then an auto-correlation analysis detects the short-period terms in this series and shows an absence of the expected terms.

Ding, Y.-R.; Xiao, N.-Y.

58

[Stabilometric features of vertical stability in healthy individuals by short-time bite change].  

PubMed

The aim of the study was to evaluate vertical stability changes according to stabilometric findings under artificial short-time disturbed occlusion. Twelve individuals were included in the study and vertical stability was assessed in stability platform before and under short-time bite change. The registered changes might be connected with an approximate reaction and random reasons. There is a possibility of bias by mechanical transfer of the stabilometric study results on the diagnosis of dental status. PMID:25588344

Pogabalo, I V; Kubriak, O V; Grokhovski?, S S; Kopetski?, I S

2014-01-01

59

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

60

Universal short-time response and formation of correlations after quantum quenches  

NASA Astrophysics Data System (ADS)

The short-time evolutions of two distinct systems, the pump and probe experiments with a semiconductor and the sudden quench of cold atoms in an optical lattice, are found to be described by the same universal response function. This analytic formula at short time scales is derived from the quantum kinetic-theory approach observing that correlations need time to form. The demand of density conservation leads to a reduction of the relaxation time by a factor of 4 in quench setups. The influence of the finite-trapping potential is derived and discussed along with Singwi-Sjølander local-field corrections including the proof of sum rules.

Morawetz, K.

2014-08-01

61

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

E-print Network

solvable parts, and further iterates this short-time propagator to longer time. This is essentially the approach of the diffusion Monte Carlo ~DMC! method.1?3 The need for iterations introduces the complication of branching, which is the hallmark... of diffu- sion and Green?s-function Monte Carlo methods.4 Our idea is to develop a short-time propagator via higher-order decom- position that can be applied for a sufficiently long time to project out an excellent approximation to the ground state...

Ciftja, O.; Chin, Siu A.

2003-01-01

62

Universal short-time response and formation of correlations after quantum quenches  

E-print Network

The short-time evolution of two distinct systems, the pump and probe experiments with semiconductor and the sudden quench of cold atoms in an optical lattice, is found to be described by the same universal response function. This analytic formula at short time scales is derived from the quantum kinetic theory approach observing that correlations need time to be formed. The demand of density conservation leads to a reduction of the relaxation time by a factor of four in quench setups. The influence of finite trapping potential is derived and discussed as well as Singwi-Sj{\\o}lander local field corrections.

K. Morawetz

2014-06-25

63

Revisiting enquiry-based teacher education in neo-liberal times  

Microsoft Academic Search

In contemporary times educators must be able to work effectively within contexts of change, paradox and instability. This has implications for programs that prepare teachers. In particular, teacher education programs should seek to develop teachers who can enquire systematically and critically into their educational practices. However, current policy approaches to teacher education in many ‘western’ countries, far from developing teachers

Alan Reid; Michael O’Donoghue

2004-01-01

64

Fall Semester: A Time for Parents to Revisit Discussions about College Drinking  

MedlinePLUS

... 24 contributes to an estimated 1,825 student deaths, 599,000 injuries, 696,000 assaults by another student who has been drinking, and 97,000 cases of sexual assault or date rape each year. EARLY WEEKS ARE CRITICAL As the fall semester begins, parents can use this important time to help prepare ...

65

Real-time mobile customer short message system design and implementation  

NASA Astrophysics Data System (ADS)

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

Han, Qirui; Sun, Fang

66

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

Microsoft Academic Search

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

Devesh B. Chokshi; Purandar Bhaduri

2010-01-01

67

Time-dependent Theory of Laser-assisted Auger Decay induced by ultra-short Pulses  

Microsoft Academic Search

A theoretical description of Auger decay induced by ultra-short pulses in the presence of a strong laser field is presented. It is based on a numerical solution of the time-dependent Schrödinger equations describing the Auger process. Appearance of the sidebands and their gross structure are discussed. With the advent of attosecond physics, the time evolution of Auger relaxation processes in

N. M. Kabachnik; A. K. Kazansky

68

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

69

Modeling, monitoring and control strategies for high temperature short time pasteurization systems — 1. Empirical model development  

Microsoft Academic Search

Dynamic models of high temperature short time (HTST) pasteurization systems can be developed by using empirical model development paradigms such as transfer functions and times series models. Properly designed experiments that excite all output variables provide good data that enable the development of accurate dynamic models. These models are used in feedback control and statistical process monitoring system design. The

Antoine Negiz; Peter Ramanauskas; Ali Çinar; Joseph E. Schlesser; David J. Armstrong

1998-01-01

70

Short Communication Single-Walled Carbon Nanotube Based Real-Time  

E-print Network

Short Communication Single-Walled Carbon Nanotube Based Real-Time Organophosphate Detector Ningyi Abstract A novel single-walled carbon nanotube (SWNT) based biosensor for real-time detection- gle-walled carbon nanotubes (SWNTs), exhibit high sensi- tivity to variations of surrounding

Chen, Wilfred

71

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

72

Residence time and collision statistics for exponential flights: the rod problem revisited.  

PubMed

Many random transport phenomena, such as radiation propagation, chemical-biological species migration, or electron motion, can be described in terms of particles performing exponential flights. For such processes, we sketch a general approach (based on the Feynman-Kac formalism) that is amenable to explicit expressions for the moments of the number of collisions and the residence time that the walker spends in a given volume as a function of the particle equilibrium distribution. We then illustrate the proposed method in the case of the so-called rod problem (a one-dimensional system), and discuss the relevance of the obtained results in the context of Monte Carlo estimators. PMID:21928981

Zoia, A; Dumonteil, E; Mazzolo, A

2011-08-01

73

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

74

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

75

Detecting Causality from Nonlinear Dynamics with Short-term Time Series  

NASA Astrophysics Data System (ADS)

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

Ma, Huanfei; Aihara, Kazuyuki; Chen, Luonan

2014-12-01

76

Revisiting the Phasor-Walkout method for detailed investigation of harmonic signals in time series  

NASA Astrophysics Data System (ADS)

A well-known but rarely used powerful method to investigate the presence of harmonic signals in time series is the Phasor Walkout method (other names are: Graphical Fourier Transform, Summation Dial, Complex Demodulation). At a given test frequency the complex contributions (phasors) to the Fourier Transform of each sample in an equidistantly sampled series are added vectorially in the complex plane. The resulting pattern, the walkout, reveals information about the properties of the signal which is not easy to obtain by other methods. Synthetic examples are used to demonstrate the resolving power of the method. The following geophysical examples for the application of this method are shown: determination of the frequency of the breathing mode0 S 0 of the earth after a large earthquake; the study of superconducting gravimeter records after a large deep earthquake used in the ‘core mode’ interpretation of a spectral peak, the study of the residual S 3 (8 h period) signal in a tidal record and the bichromatic Rayleigh-waves from Mount Pinatubo on June 15, 1991.

Zürn, W.; Rydelek, P. A.

1994-07-01

77

The differentiation trend of the Skaergaard intrusion and the timing of magnetite crystallization: iron enrichment revisited  

NASA Astrophysics Data System (ADS)

Initial studies of the Skaergaard intrusion [L.R. Wager, J. Petrol. 1 (1960) 364-398] and much of the subsequent work [R.J. Williams, Am. J. Sci. 271 (1971) 132-146; S.A. Morse et al., Am. J. Sci. 280A (1980) 159-170; A.R. McBirney, H.R. Naslund, Contrib. Mineral. Petrol. 104 (1990) 235-247; C. Tegner, Contrib. Mineral. Petrol. 128 (1997) 45-51; A.R. McBirney, Contrib. Mineral. Petrol. 132 (1998) 103-105] concluded that the Skaergaard magma followed an iron-enrichment trend with little or no silica enrichment until the final stages of crystallization. Several recent reports [R.H. Hunter, R.S.J. Sparks, Contrib. Mineral. Petrol. 95 (1987) 451-461; R.H. Hunter, R.S.J. Sparks, Contrib. Mineral. Petrol. 104 (1990) 248-254], however, have suggested that the Skaergaard magma began to follow a silica-enrichment trend in Lower Zone c (LZc) of the Layered Series where magnetite first became an abundant mineral. Magnetite in LZc, however, generally occurs in aggregates of magnetite-ulvöspinel and ilmenite-hematite that have undergone extensive subsolidus reequilibration and exsolution [E.A. Vincent, Neues Jahrb. Mineral. Abh. 94 (1960) 993-1016; E.A. Vincent, Geochim. Cosmochim. Acta 6 (1954) 1-26; A.F. Buddington, D.H. Lindsley, J. Petrol. 5 (1964) 310C357; H.R. Naslund, J. Petrol. 25 (1984) 185-212; A.R. McBirney, J. Petrol. 30 (1989) 363-397; Y.D. Jang, Petrological, Geochemical, and Mineralogical Variations in the Skaergaard Intrusion, East Greenland (Ph.D. Dissertation), State University of New York, Binghamton, NY, 1999, 219 pp.]. As a result, it is not clear if magnetite in these samples was an equilibrium, liquidus mineral fractionated from the main magma reservoir, or if magnetite crystallized as a later, interstitial mineral and did not directly affect the differentiation trend of the main Skaergaard magma. The timing of the initial crystallization of abundant magnetite and ilmenite is a key factor in understanding the trend of Skaergaard differentiation. Because V is a strongly included element in oxides, and is not strongly included in silicate minerals, the V content of an evolving magma is generally controlled by the fractionation of oxide minerals, in particular magnetite. The initial crystallization of magnetite should, therefore, be accompanied by a sudden decrease in the V content of the evolving magma, and in all of the coexisting mafic phases in equilibrium with that magma as well. The V content in Skaergaard pyroxene does not decrease significantly until the upper part of the Middle Zone (MZ), suggesting that the onset of extensive magnetite fractionation is much later than has previously been thought, and that the magnetite in LZc and the lower part of the MZ might not have been a liquidus phase at that level. The observed V trend in Skaergaard pyroxene can be modeled almost perfectly using published partition coefficients for the coexisting minerals in the Skaergaard intrusion, assuming that no magnetite fractionation occurred until the upper part of the MZ. Independently calculated trends for fO 2 in the Skaergaard magma [R.J. Williams, Am. J. Sci. 271 (1971) 132-146; S.A. Morse et al., Am. J. Sci. 280A (1980) 159-170; A.R. McBirney, H.R. Naslund, Contrib. Mineral. Petrol. 104 (1990) 235-247] change in the upper part of the MZ to more reducing conditions. The onset of magnetite fractionation would remove Fe 2O 3 from the magma and could initiate such a change. The timing of magnetite fractionation will have a strong effect on whether magma evolves towards iron enrichment or silica enrichment.

Jang, Yun D.; Naslund, H. R.; McBirney, A. R.

2001-07-01

78

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

Microsoft Academic Search

Today's neutron sources do not deliver sufficient flux to examine singular short-time events in the millisecond range by neutron radiography.However, periodic processes can be examined if a triggered accumulating detector collects information of identical time-windows and positions over several cycles of the process. The same problem applies if the source signal itself carries information, like the energy–time dependence in the

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

2005-01-01

79

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

80

Elongational Flow of Blends of Long and Short Polymers: Effective Stretch Relaxation Time  

NASA Astrophysics Data System (ADS)

We study the onset of chain stretch and emergent extension hardening in the nonlinear rheological response of molten binary blends of long and short polymers. We predict that, upon dilution with short chains, the effective stretch relaxation time of the long chains initially increases in proportion to ?L-? (where ?L is the volume fraction of long chains and ? is the dilution exponent for entanglements). We confirm this behavior experimentally, in a set of experiments that measure both the dilution exponent from linear rheology and the effective stretch relaxation time under extensional flow.

Auhl, Dietmar; Chambon, Pierre; McLeish, Tom C. B.; Read, Daniel J.

2009-09-01

81

Predicting the long-time dynamic heterogeneity in a supercooled liquid on the basis of short-time heterogeneities.  

PubMed

We report that the local Debye-Waller factor in a simulated 2D glass-forming mixture exhibits significant spatial heterogeneities and that these short-time fluctuations provide an excellent predictor of the spatial distribution of the long-time dynamic propensities. In contrast, the potential energy per particle of the inherent structure does not correlate well with the spatially distributed dynamics. PMID:16712373

Widmer-Cooper, Asaph; Harrowell, Peter

2006-05-12

82

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

NASA Astrophysics Data System (ADS)

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

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

2005-10-01

83

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

Microsoft Academic Search

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

Jerónimo Arenas-garcía; Jan Larsen; Lars Kai Hansen; Anders Meng

2006-01-01

84

Effects of the NMDA Receptor Antagonist MK-801 on Short-Interval Timing in Rats  

E-print Network

Effects of the NMDA Receptor Antagonist MK-801 on Short-Interval Timing in Rats Jonathan P. Miller with several receptor sub- types (Cotman, Monaghan, Ottersen, & Storm-Mathisen, 1987; Watkins, Krogsgaard-Larsen, & Honore, 1990). The N-methyl-D- aspartate (NMDA) receptor subtype has received much interest because

Liu, Taosheng

85

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

E-print Network

EUROGRAPHICS 2002 / N.N. Short Presentations Real Time Animated Grass Brook Bakay1 2 , Paul,heidrich¢ @cs.ubc.ca,lalonde@ea.com Abstract We present a simple method to render fields of grass, animated vector while preserving the length of the blades of grass. This technique achieves convincing results

Heidrich, Wolfgang

86

Please note the short time frame. NORTHWESTERN UNIVERSITY -OFFICE OF RESEARCH DEVELOPMENT  

E-print Network

Please note the short time frame. NORTHWESTERN UNIVERSITY - OFFICE OF RESEARCH DEVELOPMENT Limited and Reconciliation : DRL seeks to fund programs that promote tolerance, counter rising sectarianism--with a view/forced displacement, and conflict- related violence, including gender-based violence. Human Rights Protection

Contractor, Anis

87

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

88

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

89

HOT CARRIER SPACE AND TIME DEPENDENT TRANSIENTS IN SHORT CHANNEL GALLIUM ARSENIDE DEVICES55  

E-print Network

HOT CARRIER SPACE AND TIME DEPENDENT TRANSIENTS IN SHORT CHANNEL GALLIUM ARSENIDE DEVICES55 Hr in gallium arsenide when the fields change temporally and spatially at a finite rate. For temporal changes phénomènes transitoires de transport dans l'arseniure de gallium lorsque les champs varient dans le temps et

Paris-Sud XI, Université de

90

Robust blind dereverberation of speech signals based on characteristics of short-time speech segments  

Microsoft Academic Search

This paper addresses blind dereverberation techniques based on the inherent characteristics of speech signals. Two challenging issues for speech dereverberation involve decomposing reverberant observed signals into colored sources and room transfer functions (RTFs), and making the inverse filtering robust as regards acoustic and system noise. We show that short-time speech characteristics are very important for this task, and that multi-channel

Tomohiro Nakatani; Takafumi Hikichi; Keisuke Kinoshita; Takuya Yoshioka; Marc Delcroix; Masato Miyoshi; Biing-hwang Juang

2007-01-01

91

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

92

Short-Term Travel Time Prediction Using A Time-Varying Coecient Linear Model ?  

Microsoft Academic Search

Eective prediction of travel times is central to many advanced traveler informa- tion and transportation management systems. In this article we propose a method to predict freeway travel times using a linear model in which the coecients vary as smooth functions of the departure time. The method is straightforward to im- plement, computationally ecient and applicable to widely available freeway

Xiaoyan Zhang; John A. Rice

2003-01-01

93

NeuroQuantology | March 2009 | Vol 7 | Issue 1 | Page 138-151 Glicksohn J. Time production and EEG alpha revisited  

E-print Network

Revisited Joseph Glicksohn* , Aviva Berkovich Ohana Tal Balaban Dotan , Abraham Goldstein , Opher Donchin posited, what Corresponding author: Joseph Glicksohn, Ph.D. Address:*Department of Criminology, Bar

Donchin, Opher

94

Short-term memory demands of reaction-time tasks that differ in complexity  

Microsoft Academic Search

Conducted 4 experiments to determine whether the increased reaction time produced by loading memory with a set of irrelevant items depended on the complexity of (a) the stage structure or of (b) the stimulus–response (S\\/R) mapping rules underlying the task (T). Reaction-time Ts varying in complexity were performed alone and in the retention interval of a short-term memory task requiring

Gordon D. Logan

1980-01-01

95

Short-Term Cost for Long-Term Benefit: Time Preference and Cancer Control  

Microsoft Academic Search

A tradeoff between short-term costs and long-term gains characterizes many cancer control behaviors, such as behavior change (e.g., quitting smoking), screening (e.g., mammography), and prevention (e.g., healthy diet). One factor that may influence these tradeoffs is time preference, or the value assigned to future outcomes relative to immediate ones. Studies of the relationship between individual differences in time preference and

Gretchen B. Chapman

2005-01-01

96

Fluid Catalytic Cracking Catalyst Evaluation: The Short Contact Time Resid Test  

Microsoft Academic Search

The latest state?of?the?art innovation in realistic fluid catalytic cracking (FCC) catalyst testing is the short contact time resid test (SCTRT). This unit has been especially developed for residual hydrocarbon feed and solves limitations of other lab?scale testing units by allowing instantaneous mixing (injection time of 1 second) of catalyst and feed. Its unique features make the SCTRT an excellent tool

Pieter Imhof; Martin Baas; Jorge A. Gonzalez

2004-01-01

97

Short-time reactor neutron irradiation of YSZ prepared using reactive calcination method  

NASA Astrophysics Data System (ADS)

The present work is devoted to study the short-time reactor neutron irradiation of yttria stabilised zirconia (YSZ) at 315 K. The samples were prepared by the reactive calcination method and characterised by X-ray diffraction (XRD) analysis and scanning electronic microscope. The prepared samples were irradiated by reactor neutrons at different exposure times and investigated by XRD analysis. The results obtained show good radiation resistance of YSZ to reactor neutron irradiation.

Izerrouken, M.; Boucheffa, Y.; Souami, S.; Sari, A.; Hammache, A.; Meftah, A.; Nekab, M.

2006-05-01

98

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

99

A short-time fading study of Al2O3:C  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

100

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

NASA Astrophysics Data System (ADS)

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

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

2005-04-01

101

Concentration-time-response modeling for acute and short-term exposures.  

PubMed

Risk of health effects from acute and short-term exposure depends on exposure time as well as exposure concentration. A general approach to extending a concentration-response model to include time as a variable is described using mortality of rats exposed to hydrogen sulfide (H(2)S) as an example. This particular example resulted in a logit model with concentration-time (c-t) relationship linear in time and log-concentration. It provided an improved statistical fit, based on the Akaike information criterion in the observed time range, 30 m-360 m, over implementing the c-t relationship of [ten Berge, W.F., Zwart, A., Appelman, L.M., 1986. Concentration-time mortality response relationship of irritant and systemically acting vapours and gases. J. Hazard. Mater. 13, 301--309] as a default in the logit model. This approach also indicated that there might be a fundamental difference in the relationship between concentration, time, and response at short exposure times, somewhere less than 30 m, a hypothesis for further consideration from a biological perspective. In general, the proposed approach provides flexibility to develop a concentration-time-response model, and the associated concentration-time relationship, from the data. Interpretation and potential implications, however, need to be considered within the context of biological plausibility as well. Implementation of the proposed approach requires adequate data for separate concentration-response modeling at each of several exposure durations. PMID:16111795

Brown, Kenneth G; Foureman, Gary L

2005-10-01

102

Probing ECG-based mental state monitoring on short time segments.  

PubMed

Electrocardiography is used to provide features for mental state monitoring systems. There is a need for quick mental state assessment in some applications such as attentive user interfaces. We analyzed how heart rate and heart rate variability features are influenced by working memory load (WKL) and time-on-task (TOT) on very short time segments (5s) with both statistical significance and classification performance results. It is shown that classification of such mental states can be performed on very short time segments and that heart rate is more predictive of TOT level than heart rate variability. However, both features are efficient for WKL level classification. What's more, interesting interaction effects are uncovered: TOT influences WKL level classification either favorably when based on HR, or adversely when based on HRV. Implications for mental state monitoring are discussed. PMID:24111258

Roy, Raphaelle N; Charbonnier, Sylvie; Campagne, Aurelie

2013-01-01

103

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

104

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

105

Tests of the exponential decay law at short and long times  

SciTech Connect

We have studied the ..beta.. decays of /sup 60/Co at times approx. <10/sup -4/t/sub 1/2 and those of /sup 56/Mn over the interval 0.3t/sub 1/2less than or equal totless than or equal to45t/sub 1/2 to search for proposed deviations from the exponential decay law at short and long times, respectively. Over all time periods examined, our data are consistent with purely exponential behavior. From these measurements, stringent limits are derived on the amplitudes of possible deviations from the exponential decay law.

Norman, E.B.; Gazes, S.B.; Crane, S.G.; Bennett, D.A.

1988-05-30

106

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

107

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

108

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

SciTech Connect

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

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

1996-05-01

109

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

110

Use of short-time NH3 gas flow during Al milling  

NASA Astrophysics Data System (ADS)

Samples from mechanically alloyed aluminium powder were prepared by a simple press and sintering method in order to study the influence of a flow of ammonia gas during a short time of the milling process. All milling experiences were carried out at room temperature for a total of 10 hours. Millings were carried out in vacuum or under confined ammonia. This last type allows to incorporate nitrogen-rich second phases, mainly aluminium nitride (Al3CON) and oxynitride (Al5O6N), after powder sintering. To control the amounts of the second phases, a new milling type, using ammonia gas flow during 5 minutes followed by vacuum milling, was carried out. Testing of sintered samples shows that milling using ammonia, both confined and in flow, substantially improves mechanical properties. Furthermore, the use of a very short time gas flow allows obtaining compacts with similar tensile strength (485 MPa) to those obtained after milling in confined ammonia for 10 h.

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

2013-12-01

111

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

SciTech Connect

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

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

2009-03-20

112

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

113

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

NASA Astrophysics Data System (ADS)

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

Niu, Hongli; Wang, Jun

2015-05-01

114

Multicomponent FM demodulation of speech based on the short-time Fourier transform (STFT) phase  

NASA Astrophysics Data System (ADS)

Speech is a signal which is produced as a combination of frication and a quasi periodic train of glottal pulses excites the vocal tract and causes it to resonate. Information is encoded on the signal as the vocal tract changes configuration, resulting in a rapid change of the resonant frequencies. We develop methods, based on differentiation of the short time Fourier transform (STFT) phase, which effectively demodulates the speech signal and produces accurate, high resolution time-frequency estimates of both the resonances and the signal excitation. The method effectively condenses the STFT surface along curves representing the instantaneous frequencies of the vocal tract resonances and the channel group delay function.

Nelson, Douglas J.

2001-03-01

115

Muonic hydrogen cascade time and lifetime of the short-lived $2S$ state  

E-print Network

Metastable ${2S}$ muonic-hydrogen atoms undergo collisional ${2S}$-quenching, with rates which depend strongly on whether the $\\mu p$ kinetic energy is above or below the ${2S}\\to {2P}$ energy threshold. Above threshold, collisional ${2S} \\to {2P}$ excitation followed by fast radiative ${2P} \\to {1S}$ deexcitation is allowed. The corresponding short-lived $\\mu p ({2S})$ component was measured at 0.6 hPa $\\mathrm{H}_2$ room temperature gas pressure, with lifetime $\\tau_{2S}^\\mathrm{short} = 165 ^{+38}_{-29}$ ns (i.e., $\\lambda_{2S}^\\mathrm{quench} = 7.9 ^{+1.8}_{-1.6} \\times 10^{12} \\mathrm{s}^{-1}$ at liquid-hydrogen density) and population $\\epsilon_{2S}^\\mathrm{short} = 1.70^{+0.80}_{-0.56}$ % (per $\\mu p$ atom). In addition, a value of the $\\mu p$ cascade time, $T_\\mathrm{cas}^{\\mu p} = (37\\pm5)$ ns, was found.

Ludhova, L; Antognini, A; Biraben, F; Cardoso, J M R; Conde, C A N; Dax, A; Dhawan, S; Dos Santos, J M F; Fernandes, L M P; Hughes, V W; Hänsch, T W; Indelicato, P J; Julien, L; Knowles, P E; Kottmann, F; Liu, Y W; Lopes, J A M; Monteiro, C M B; Mulhauser, F; Nez, F; Pohl, R; Rabinowitz, P; Schaller, L A; Schwob, C; Taqqu, D; Veloso, J F C A

2006-01-01

116

EQUIVALENCE BETWEEN SHORT-TIME BIPHASIC AND INCOMPRESSIBLE ELASTIC MATERIAL RESPONSES  

PubMed Central

Porous-permeable tissues have often been modeled using porous media theories such as the biphasic theory. This study examines the equivalence of the short-time biphasic and incompressible elastic responses for arbitrary deformations and constitutive relations from first principles. This equivalence is illustrated in problems of unconfined compression of a disk, and of articular contact under finite deformation, using two different constitutive relations for the solid matrix of cartilage, one of which accounts for the large disparity observed between the tensile and compressive moduli in this tissue. Demonstrating this equivalence under general conditions provides a rationale for using available finite element codes for incompressible elastic materials as a practical substitute for biphasic analyses, so long as only the short-time biphasic response is sought. In practice, an incompressible elastic analysis is representative of a biphasic analysis over the short-term response ?t??2/?C4?||K||, where ? is a characteristic dimension, C4 is the elasticity tensor and K is the hydraulic permeability tensor of the solid matrix. Certain notes of caution are provided with regard to implementation issues, particularly when finite element formulations of incompressible elasticity employ an uncoupled strain energy function consisting of additive deviatoric and volumetric components. PMID:17536908

Ateshian, Gerard A.; Ellis, Benjamin J.; Weiss, Jeffrey A.

2009-01-01

117

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

SciTech Connect

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

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

1994-06-01

118

Short-term cost for long-term benefit: time preference and cancer control.  

PubMed

A tradeoff between short-term costs and long-term gains characterizes many cancer control behaviors, such as behavior change (e.g., quitting smoking), screening (e.g., mammography), and prevention (e.g., healthy diet). One factor that may influence these tradeoffs is time preference, or the value assigned to future outcomes relative to immediate ones. Studies of the relationship between individual differences in time preference and preventive health behaviors, however, have yielded mixed results. Time preference is related to addictive behaviors (e.g., smoking) but not to other preventive health behaviors (e.g., vaccination). This pattern of results suggests that time preference measures reflect an ability to forgo immediate gratification that is applicable to hot behaviors, such as smoking, but not to cold behaviors, such as vaccination. PMID:16045418

Chapman, Gretchen B

2005-07-01

119

Molecular Cell Short Review  

E-print Network

catalyzed by the five natu- rally occurring small ribozymes, the hammerhead, hairpin, hepatitis delta virus simplicity of their chemical makeup, ribozymes can form complex tertiary structures, as perhaps bestMolecular Cell Short Review Ribozyme Catalysis Revisited: Is Water Involved? Nils G. Walter1,* 1

Walter, Nils G.

120

Time-domain imaging of radar targets using ultra-wideband or short pulse radars  

NASA Astrophysics Data System (ADS)

The development of viable short-pulse radar system has renewed the interest in time domain imaging performed directly in time-domain with temporally measured signal. Since the short-pulse response of a target provides significant information about the positions and strengths of scattering centers, and if observations are made over a wide range of aspect angle, one might create an image of the target using the short-pulse response information. In this thesis, we have developed and implemented a time-domain radar imaging technique based on a space-time magnetic field integral equation, using a sine modulated exponential pulse, and employing the inverse Radon transform. Images of various aircraft models were created from measured target responses over a wide band of frequencies and over the entire range of aspect angles. For the limited-view problem, two techniques have been proposed to process this practical situation. One of the approaches is the method of projections onto convex sets (POCS) which has been used in image processing for a long time. We extend this approach to radar imaging for the first time and show some useful results. Another approach which we have demonstrated is to process the available measured projections in order to generate an estimate of the full set of projections, an image which is called a sinogram. The goal of this approach is to recover the sinogram from the available measured data using linear prediction. Since the scattered field of a target can be written as a superposition of distinct specular reflection arising from scattering centers on the target, the position and strength of the scattering centers can be predicted using linear prediction with the change of the observation angle. Thus the missing data can be predicted before reconstructing the image. In the imaging of complex radar target, the PO approximation is used in the reconstruction algorithm. However, the PO approximation is inadequate for scattering problems of a complex shaped conducting object such as aircraft. At high frequency, edge diffractions, multiple reflections, creeping waves, and surface travelling waves may also be important scattering mechanisms. Additionally, the spectral and angular windows for data are usually restricted by practical constraints. Therefore the time domain image of a aircraft may be different from their geometrical shape. We have investigated time domain imaging of aircraft employing SMEP responses, and interpret the reconstructed image from a new approach, based on analysis of the scattering mechanisms and the back-projection algorithm utilized in image retrieval. The time-domain inverse scattering identity with the incorporation of Geometrical Theory of Diffraction (GTD) is derived and some interesting experimental results are provided.

Dai, Yingcheng

121

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

PubMed

Relaxation in the nematic liquid crystalline phase is known to be sensitive to its proximity to both isotropic and smectic phases. Recent transient optical Kerr effect (OKE) studies have revealed, rather surprisingly, two temporal power laws at short to intermediate times and also an apparent absence of the expected exponential decay at longer times. In order to understand this unusual dynamics, we have carried out extensive molecular dynamics simulations of transient OKE and related orientational time correlation functions in a system of prolate ellipsoids (with aspect ratio equal to 3). The simulations find two distinct power laws, with a crossover region, in the decay of the orientational time correlation function at short to intermediate times (in the range of a few picoseconds to a few nanoseconds). In addition, the simulation results fail to recover any long time exponential decay component. The system size dependence of the exponents suggests that the first power law may originate from the local orientational density fluctuations (like in a glassy liquid). The origin of the second power law is less clear and may be related to the long range fluctuations (such as smecticlike density fluctuations)--these fluctuations are expected to involve small free energy barriers. In support of the latter, the evidence of pronounced coupling between orientational and spatial densities at intermediate wave numbers is presented. This coupling is usually small in normal isotropic liquids, but it is large in the present case. In addition to slow collective orientational relaxation, the single particle orientational relaxation is also found to exhibit slow dynamics in the nematic phase in the long time. PMID:17115789

Jose, Prasanth P; Bagchi, Biman

2006-11-14

122

Quantum Rate Constants from Short-Time Dynamics: An Analytic Continuation Eunji Sim, Goran Krilov, and B. J. Berne*  

E-print Network

. The rate constant is expressed as the time integral of the real-time flux autocorrelation function. The real-time flux autocorrelation function is evaluated for short times fully quantum mechanically by path of the oscillatory nature of the real-time propagator which leads to dramatic phase cancellation and failure of MC

Berne, Bruce J.

123

Spectral phase encoding of ultra-short optical pulse in time domain for OCDMA application.  

PubMed

We propose a novel reconfigurable time domain spectral phase encoding (SPE) scheme for coherent optical code-division-multiple-access application. In the proposed scheme, the ultra-short optical pulse is stretched by dispersive device and the SPE is done in time domain using high speed phase modulator. The time domain SPE scheme is robust to wavelength drift of the light source and is very flexible and compatible with the fiber optical system. Proof-of-principle experiments of encoding with 16-chip, 20 GHz/chip binary-phase-shift-keying codes and 1.25 Gbps data transmission have been successfully demonstrated together with an arrayed-wave-guide decoder. PMID:19547055

Wang, Xu; Wada, Naoya

2007-06-11

124

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

125

Stellar scintillation in short exposure regime and atmospheric coherence time evaluation  

E-print Network

Accurately measuring the atmospheric coherence time is still an important problem despite a variety of applicable methods. The Multi-aperture scintillation sensor (MASS) designed for the vertical profiling of optical turbulence, also provides a measurements of coherence time, but its results were found to be biased. Hence there is a need for a more robust method to determine $\\tau_0$. The effect of smoothing the stellar scintillation by a finite exposure of the detector is considered. The short exposure regime is described and its limits are defined. The re-analysis of previous measurements with the MASS is performed in order to test the applicability of this approach in real data processing. It is shown that most of the actual measurements satisfy the criteria of short exposures. The expressions for the mean wind speeds $\\bar V_2$ in the free atmosphere from the measurement of the scintillation indices are derived for this regime. These values provide an estimate of the atmospheric coherence time $\\tau_0$ wi...

Kornilov, Victor

2011-01-01

126

An iterative algorithm for cell segmentation using short-time Fourier transform.  

PubMed

In this paper, an iterative cell image segmentation algorithm using short-time Fourier transform magnitude vectors as class features is presented. The cluster centroids of the magnitude vectors are obtained by the K-means clustering method and used as representative class features. The initial image segmentation classifies only those image pixels whose surrounding closely matches a class centroid. The subsequent procedure iteratively classifies the remaining image pixels by combining their spatial distance from the regions already segmented and the similarities between their corresponding magnitude vectors and the cluster centroids. Experimental results of the proposed algorithm for segmenting real cell images are provided. PMID:8972098

Wu, H S; Barba, J; Gil, J

1996-11-01

127

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

128

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

129

Protein supplementation during a short-interval prostaglandin-based protocol for timed AI in sheep.  

PubMed

The aim of this experiment was to improve the reproductive performance of a short-interval prostaglandin (PG)-based protocol for timed artificial insemination in sheep, using a short-term nutritional treatment. During the breeding season (March-April), 132 multiparous and 61 nulliparous Corriedale ewes grazing natural pastures (600 kg DM/ha, 8.5% CP), were allocated to two groups: 1, Control group (n=100) two injections of D-Cloprostenol (75 ?g per dose, 7d apart: Synchrovine(®) protocol); and 2, Supplemented group (n=93) ewes in which stage of the oestrous cycle was synchronised with Synchrovine(®) protocol plus focus feeding of a protein supplement (33.8% CP) between PG doses (Day -7 to -2). Cervical AI was performed at fixed time (Day 0), 46 ± 1.0 h after the second PG injection using 150 million sperm per ewe. Ovulation rate (Day 10), pregnancy rate, prolificacy and fecundity at Day 69 were evaluated by ultrasonography. Ovulation rate at Day 10 (1.20 ± 0.05 vs. 1.22 ± 0.05), pregnancy (46 ± 0.05 vs. 56 ± 0.05), prolificacy (1.09 ± 0.04 vs. 1.06 ± 0.05), and fecundity (0.49 ± 0.06 vs. 0.59 ± 0.06) at Day 69, were similar between groups (P>0.05; Control and Supplemented group respectively). It is concluded that focus feeding for 6d with protein supplementation during a short-interval PG-based protocol (Synchrovine(®)) did not improve the reproductive outcome associated with this protocol. PMID:25129637

Fierro, S; Gil, J; Viñoles, C; Soca, F; Banchero, G; Olivera-Muzante, J

2014-10-01

130

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

131

Atmospheric Array Loss Statistics Derived from Short Time Scale Site Test Interferometer Phase Data  

NASA Astrophysics Data System (ADS)

NASA is interested in using the technique of arraying smaller-diameter antennas to increase effective aperture to replace the aging 70-m-diameter antennas of the Deep Space Network (DSN). Downlink arraying using the 34-m-diameter and 70-m-diameter antennas is routinely performed. Future scenarios include extending the technique to uplink arraying where a downlink signal may not be available. Atmospheric turbulence causes decorrelation of the arrayed signal, and becomes more severe at higher frequencies such as at the uplink allocations near 34 GHz and 40 GHz. This article expands the study initiated in a previous article that focused on average array loss statistics extracted from Site Test Interferometer (STI) data. In that study, cumulative distributions of the annual and monthly expected phasing loss were derived from STI data collected at the Goldstone and Canberra DSN complexes. For a two-element array, the average array loss cannot exceed 3 dB. This article considers the instantaneous (short time scale) array loss that sometimes exceeds 3 dB for a two-element array. We also consider cases of three-element arrays, which behave somewhat differently. The short time scale statistics of array loss at 7.15 GHz and 34.5 GHz are compared against the average array loss statistics for the best-case and worst-case weather months for the Goldstone and Canberra DSN sites.

Morabito, David D.; D'Addario, Larry R.

2014-08-01

132

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

PubMed

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

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

2014-11-01

133

Characterization of nitrifying microbial community in a submerged membrane bioreactor at short solids retention times.  

PubMed

This study investigated the nitrifying bacterial community in membrane bioreactor (MBR) at short solids retention times (SRTs) of 3, 5 and 10 days. The denaturing gradient gel electrophoresis results showed that different types of ammonia-oxidizing bacteria (AOB) can survive at different operating conditions. The diversity of AOB increased as the SRT increased. The real-time PCR results showed that the amoA gene concentrations were similar when MBRs were stabilized, and it can be a good indicator of stabilized nitrification. The results of clone library indicated that Nitrosomonas was the dominant group of AOB in three reactors. The microarray results showed that Nitrospira was the dominant group of nitrite-oxidizing bacteria (NOB) in the system. All groups of AOB and NOB except Nitrosolobus and Nitrococcus were found in MBR, indicated that the nitrifying bacterial community structure was more complicated. The combination of some molecular tools can provide more information of microbial communities. PMID:24099975

Duan, Liang; Song, Yonghui; Xia, Siqing; Hermanowicz, Slawomir W

2013-12-01

134

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

135

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

136

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

137

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

138

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

139

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

NASA Astrophysics Data System (ADS)

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

Xu, Ming; Huang, Li

2014-08-01

140

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

141

Catalytic incineration of VOC containing air streams at very short contact times  

SciTech Connect

A short-contact-time catalytic combustor described here is capable of incinerating air streams with low concentrations of volatile organic compounds (VOCs) at conversions exceeding 99.5% for contact times on the order of 5 ms. This is accomplished by adding methane to the VOC-containing air stream to increase the fuel stream value and then passing the mixture over a platinum-coated foam ceramic monolith at 900--1,400 C. The incineration of air streams containing toluene, chlorobenzene, acetonitrile, and thiophene was examined at concentrations ranging from 500 to 2,000 PPM. Residence time and methane concentration do not affect strongly the outlet concentration of the VOC and conversion. Greater than 99.5% conversion is observed for all compounds examined for residence times ranging from 4 to 12 ms and methane concentrations from 5.5 to 7.0% (80--40% excess air). The mechanism of reaction in this system is primarily heterogeneous, with some homogeneous reactions driven by the heat liberated by the heterogeneous reactions. A simple homogeneous model shows that homogeneous chemistry alone cannot account for complete conversion of the additional methane fuel at the reaction conditions described.

Goralski, C.T. Jr.; Schmidt, L.D. [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science] [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science; Brown, W.L. [Rust Environment and Infrastructure, Minneapolis, MN (United States)] [Rust Environment and Infrastructure, Minneapolis, MN (United States)

1998-08-01

142

Facial emotion modulates the neural mechanisms responsible for short interval time perception.  

PubMed

Emotionally arousing events can distort our sense of time. We used mixed block/event-related fMRI design to establish the neural basis for this effect. Nineteen participants were asked to judge whether angry, happy and neutral facial expressions that varied in duration (from 400 to 1,600 ms) were closer in duration to either a short or long duration they learnt previously. Time was overestimated for both angry and happy expressions compared to neutral expressions. For faces presented for 700 ms, facial emotion modulated activity in regions of the timing network Wiener et al. (NeuroImage 49(2):1728-1740, 2010) namely the right supplementary motor area (SMA) and the junction of the right inferior frontal gyrus and anterior insula (IFG/AI). Reaction times were slowest when faces were displayed for 700 ms indicating increased decision making difficulty. Taken together with existing electrophysiological evidence Ng et al. (Neuroscience, doi: 10.3389/fnint.2011.00077 , 2011), the effects are consistent with the idea that facial emotion moderates temporal decision making and that the right SMA and right IFG/AI are key neural structures responsible for this effect. PMID:24370610

Tipples, Jason; Brattan, Victoria; Johnston, Pat

2015-01-01

143

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

144

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

145

Test particle acceleration by non-uniform MHD fields in short time scales  

NASA Astrophysics Data System (ADS)

We consider the acceleration of test particles in non-uniform electric and magnetic fields obtained from direct numerical solutions of the MHD equations in a turbulent regime. Numerical experiments are performed for cases with and without a strong background magnetic field and results are compared. Distribution functions of the particles velocities are computed at short time scales and the appearance of anisotropic effects is studied. We found different behavior according to the particle motion lengthscale compared to the turbulent correlation scale and the dissipative scales. An acceleration mechanism by fields in reconnection geometries is proposed to explain qualitatively the behavior of the particles. A question remains as to how these results relate to the understanding of the self-consistent heating of solar protons and electrons. Work supported by NSF grant ATM-9977692 and DOE grant DE-FG02-98ER54490.

Dmitruk, P.; Matthaeus, W. H.

2004-05-01

146

Evidence for two distinct morphological classes of gamma-ray bursts from their short time scale variability  

NASA Technical Reports Server (NTRS)

We have analyzed the 241 bursts for which peak counts (C)max exist in the publicly available Burst and Transient Source Experiment (BATSE) catalog. Introducing peak counts in 1024 ms as a measure of burst brightness B and the ratio of peak counts in 64 and 1024 ms as a measure of short timescale variability V, we find a statistically significant correlation between the brightness and the short time scale variability of gamma-ray bursts. The bursts which are smoother on short time scales are both faint and bright, while the bursts which are variable on short time scales are faint only, suggesting the existence of two distinct morphological classes of bursts.

Lamb, D. Q.; Graziani, C.; Smith, I. A.

1993-01-01

147

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

NASA Astrophysics Data System (ADS)

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

Hall, C. M.

2014-01-01

148

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

149

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

150

Time estimation among low-functioning individuals with autism spectrum disorders: evidence of poor sensitivity to variability of short durations.  

PubMed

Time estimation of short durations (under 1 sec) was examined in low-functioning individuals with autism spectrum disorder (ASD) and typically developing (TD) children matched on mental age. Temporal bisection and generalization tasks were used to examine basic perceptual timing mechanisms. For both tasks, the participants with ASD demonstrated less sensitivity to variability in short durations than the TD children, adding to a growing body of literature suggesting deficits in timing exist for longer durations. The results highlight the need to examine multiple levels of processing of time-related information from basic perceptual mechanisms to higher level cognitive mechanisms. PMID:24574256

Brodeur, Darlene A; Gordon Green, Cathryn; Flores, Heidi; Burack, Jacob A

2014-04-01

151

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

152

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

153

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

154

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

155

Short-time creep and rupture tests on high burnup fuel rod cladding  

NASA Astrophysics Data System (ADS)

Short-time creep and rupture tests were performed to assess the strain potential of cladding of high burnup fuel rods under conditions of dry storage. The tests comprised optimized Zry-4 cladding samples from fuel rods irradiated to burnups of up to 64 MWd/kg U and were carried out at temperatures of 573 and 643 K and at hoop stresses of about 400 and 600 MPa. The applied stresses were chosen to reach about 2% strain within an envisaged testing time of 3-4 days. The tests were followed by a low temperature phase at 423 K and 100 MPa to assess the long-term behaviour of the cladding ductility especially with regard to the higher hydrogen content in the cladding of the high burnup fuel. These tests showed that around 600 K, a uniform plastic strain of at least 2% is reached without cladding failure. The low temperature phase at 423 K for up to 5 days revealed no cladding failure under these conditions of reduced cladding ductility due to the increased hydrogen content.

Goll, W.; Spilker, H.; Toscano, E. H.

2001-03-01

156

Short-time diffusion in concentrated bidisperse hard-sphere suspensions  

E-print Network

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 120A, 388 (1983) & 126A, 349 (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 $\\delta\\gamma$-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 $\\delta\\gamma$ 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 $40\\%$.

Mu Wang; Marco Heinen; John F. Brady

2014-10-31

157

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

158

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

PubMed

Complementary food is needed when breast milk (or infant formula) alone is no longer sufficient for both nutritional and developmental reasons. The timing of its introduction, therefore, is an individual decision, although 6 months of exclusive breastfeeding can be recommended for most healthy term infants. The new foods are intended to 'complement' ongoing breastfeeding with those dietary items whose intake has become marginal or insufficient. Both breastfeeding and complementary feeding can have direct or later consequences on health. The evaluation of consequences of both early and late introduction of complementary food can neither disregard the effect of breastfeeding compared to formula feeding nor the composition or quality of the complementary food. Possible short-term health effects concern growth velocity and infections, and possible long-term effects may relate to atopic diseases, type 1 and 2 diabetes, obesity and neuromuscular development. On the basis of the currently available evidence, it is impossible to exactly determine the age when risks related to the start of complementary feeding are lowest or highest for most of these effects, with the possible exception of infections and early growth velocity. The present knowledge on undesirable health effects, however, is mainly based on observational studies, and although some mechanisms have been proposed, further prospective studies have to clarify these unsolved issues. Even less evidence on the consequences of the timing of complementary food introduction is available for formula-fed infants. PMID:22555185

Przyrembel, Hildegard

2012-01-01

159

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

160

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

ERIC Educational Resources Information Center

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

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

2014-01-01

161

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

162

EUROGRAPHICS '0x / N.N. and N.N. Short Paper Real-Time Importance Sampling  

E-print Network

EUROGRAPHICS '0x / N.N. and N.N. Short Paper Real-Time Importance Sampling of Dynamic Environment Maps H. Lu1 R. Pacanowski1 X. Granier1§ Inria - Univ. Bordeaux CNRS, LP2N IOGS, LP2N 1. Inria Bordeaux Sud-Ouest - LP2N (Univ. Bordeaux, IOGS, CNRS) - LaBRI (Univ. Bordeaux, CNRS) Figure 1: Time

Boyer, Edmond

163

Biosensors & Bioelectronics 16 (2001) 503512 Methods for short time series analysis of cell-based biosensor data  

E-print Network

Biosensors & Bioelectronics 16 (2001) 503­512 Methods for short time series analysis of cell-based biosensor data Ira B. Schwartz a, *, Lora Billings a , Joseph J. Pancrazio b , Joel M. Schnur b a Na6al by Elsevier Science B.V. Keywords: Spiking; Neurons; Time series; Nonlinear dynamics; Biosensors; Delay

Billings, Lora

164

The Irradiation and Recent Thermal History of QUE 94281 and Other Lunar Meteorites: Evidence for Short Transit Times  

Microsoft Academic Search

The recent history of lunar meteorites can be divided into three stages, including time spent on or near the lunar surface, ejection into space and transit to Earth, and time spent on Earth. Most lunar meteorites have short terrestrial ages and cosmic ray exposure (CRE) ages compared to most basaltic meteorites. It should, however, be noted that these \\

P. H. Benoit; S. J. K. Symes; D. W. G. Sears

1996-01-01

165

Conditioning and time representation in long short-term memory networks.  

PubMed

Dopaminergic models based on the temporal-difference learning algorithm usually do not differentiate trace from delay conditioning. Instead, they use a fixed temporal representation of elapsed time since conditioned stimulus onset. Recently, a new model was proposed in which timing is learned within a long short-term memory (LSTM) artificial neural network representing the cerebral cortex (Rivest et al. in J Comput Neurosci 28(1):107-130, 2010). In this paper, that model's ability to reproduce and explain relevant data, as well as its ability to make interesting new predictions, are evaluated. The model reveals a strikingly different temporal representation between trace and delay conditioning since trace conditioning requires working memory to remember the past conditioned stimulus while delay conditioning does not. On the other hand, the model predicts no important difference in DA responses between those two conditions when trained on one conditioning paradigm and tested on the other. The model predicts that in trace conditioning, animal timing starts with the conditioned stimulus offset as opposed to its onset. In classical conditioning, it predicts that if the conditioned stimulus does not disappear after the reward, the animal may expect a second reward. Finally, the last simulation reveals that the buildup of activity of some units in the networks can adapt to new delays by adjusting their rate of integration. Most importantly, the paper shows that it is possible, with the proposed architecture, to acquire discharge patterns similar to those observed in dopaminergic neurons and in the cerebral cortex on those tasks simply by minimizing a predictive cost function. PMID:24258005

Rivest, Francois; Kalaska, John F; Bengio, Yoshua

2014-02-01

166

Short GRBs: Slashing Through the Jungle One Step at a Time  

NASA Astrophysics Data System (ADS)

We are learning in the Swift era that short and long bursts have very different origins. The short bursts appear to have old-population stellar progenitors and the long bursts certainly have young-population progenitors. However, the going is tough for short bursts, with low event rates and weak afterglows. Hints of sub-populations are emerging in distance range, progenitor type and lightcurve characteristics. This paper will discuss the growing Swift data set on short bursts and where it is leading.

Gehrels, Neil

2008-03-01

167

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

168

Cyp11A1 canola plants under short time heat stress conditions.  

PubMed

In order to investigate the high temperature tolerance of spring canola plants (Brassica napus L.) constitutively expressing cyp11A1 gene which encodes bovine cytochrome P450(scc) the growth features were analyzed under short time heat stress (42 degrees C) in growth chamber. Earlier it was documented that results of the heat tolerance test positively correlated with improvement of high temperature resistance in field trial. Higher relative water content (by 13%) and superoxide dismutase (SOD) activity, lower electrolyte leakage (up 1.4-fold) and smaller increase in chlorophyll a and carotenoid contents in cyp11A1 canola leaves in comparison with wild-type plants under stress allowed to conclude cyp11A1 plants are more tolerant to high temperature than the control ones. We suppose that SOD activity increase which revealed in our transgenic canola in normal condition plays the defining role in the biochemical alterations in plant metabolism for the thermotolerance improvement. SOD activity increment could be caused by heterologous cytochrome P450(scc) activity which resulted in the superoxide radical formation. Cyp11A1 canola plants might be resistant to the other stress conditions of different origin. PMID:25318172

Sakhno, L O; Slyvets, M S; Kuchuk, M V

2014-01-01

169

The influence of alcoholic intoxication on the short-time energy function of speech.  

PubMed

This study investigates rhythmic features based on the short-time energy function of speech signals with the aim of finding robust, speaker-independent features that indicate speaker intoxication. Data from the German Alcohol Language Corpus, which comprises read, spontaneous, and command&control speech uttered by 162 speakers of both genders and various age groups when sober and intoxicated, were analyzed. Energy contours are compared directly (Root Mean Squared Error, statistical correlation, or the Euclidean distance in the spectral space of the contour) and by parameterization of the contour using the Discrete Cosine Transform (DCT) and the first and second moments of the lower DCT spectrum. Contours are also analyzed by Principal Components Analysis aiming at fundamental "eigen contour" changes that might encode intoxication. Energy contours differ significantly with intoxication in terms of distance measures, the second and fourth DCT coefficients, and the first and second moments of the lower DCT spectrum. Principal Components Analysis did not yield interpretable "eigen contours" that could be used in distinguishing intoxicated from sober contours. PMID:24815274

Heinrich, Christian; Schiel, Florian

2014-05-01

170

SHORT CONTACT TIME DIRECT COAL LIQUEFACTION USING A NOVEL BATCH REACTOR  

SciTech Connect

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

Michael T. Klein; William H. Calkins

1997-10-29

171

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

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

172

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

173

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

174

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

Microsoft Academic Search

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

Christos T. Maravelias; Ignacio E. Grossmann

2003-01-01

175

Revisiting the golden triangle of cost, time and quality: the role of NPV in project control, success and failure  

Microsoft Academic Search

The paper examines the relationship between project budgets, cash flow, cost control and time schedules. It considers the theoretical effect that each can have on the net present value (NPV) of a project. The paper proposes that investment appraisal techniques, such as NPV, can and should be used as an ongoing monitor of project health. Finally, the theoretical points are

Paul D Gardiner; Kenneth Stewart

2000-01-01

176

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

ERIC Educational Resources Information Center

The impact of part-time employment on adolescent functioning remains unclear because most studies fail to adequately control for differential selection into the workplace. The present study reanalyzes data from L. Steinberg, S. Fegley, and S. M. Dornbusch (1993) using multiple imputation, which minimizes bias in effect size estimation, and 2 types…

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

2011-01-01

177

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

178

Pearlite revisited  

NASA Astrophysics Data System (ADS)

Zener's model of pearlite transformation in steels can be viewed as the prototype of many microstructure evolution models in materials science. It links principles of thermodynamics and kinetics to the scale of the microstructure. In addition it solves a very practical problem: How the hardness of steel is correlated to the conditions of processing. Although the model is well established since the 1950s, quantitative explanation of growth kinetics was missing until very recently. The present paper will shortly review the classical model of pearlite transformation. Zener's conjecture of maximum entropy production will be annotated by modern theoretical and experimental considerations of a band of stable (sometimes oscillating) states around the state of maximum entropy production. Finally, an explanation of the growth kinetics observed in experiments is proposed based on diffusion fluxes driven by stress gradients due to large transformation strain.

Steinbach, Ingo; Plapp, Mathis

2012-11-01

179

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

Microsoft Academic Search

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

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

2001-01-01

180

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

Microsoft Academic Search

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

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

2001-01-01

181

Time-of-flight measurement of the temperature of cold atoms for short trap-probe beam distances  

Microsoft Academic Search

We analyse the time-of-flight method of measuring the temperature of cold trapped atoms in the specific case of short distances of the probe beam from the trap centre and finite atomic cloud size. We theoretically examine the influence of the probe beam shape and its distance from the initial position of the cloud on the temperature evaluation. These results are

Tomasz M. Brzozowski; Maria Maczynska; Michal Zawada; Jerzy Zachorowski; Wojciech Gawlik

2002-01-01

182

Body-condition indices are repeatable across short, but not long, time periods in crimson finches Neochmia phaeton.  

PubMed

Abstract It is common in evolutionary ecology to interpret body-condition indices as indicators of individual quality, but this hypothesized relationship has been questioned and remains poorly validated. Here, we test one of the fundamental predictions of this condition-quality hypothesis, that relative-condition indices are repeatable within individuals, that is, that the index score of an individual relative to others is consistent over time. We sampled crimson finches (Neochmia phaeton) for seven commonly used condition indices and tested whether individual condition relative to conspecifics in the same context (e.g., breeding stage) was repeatable. We calculated the relative indices' repeatability across several temporal scales, from short (within breeding season) to long (more than 2 yr) time periods, as well as without consideration of timescale. Most relative-condition indices were repeatable when sampled without consideration of timescale, all were repeatable within a short time period, and none were repeatable over the longest time period. This provides only partial support for the condition-quality hypothesis, because although relative-condition indices were generally repeatable, this was primarily attributed to short-term, instead of long-term, repeatability. Condition indices may be meaningful indicators of short-term survival or fitness potential, but our findings are inconsistent with the idea that condition indices are indicators of inherent individual quality. PMID:24940919

Milenkaya, O; Legge, S; Walters, J R

2014-01-01

183

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

184

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.

185

Short time dynamics in the isotropic phase of liquid crystals: the aspect ratio and the power law decay  

E-print Network

, USA Received 14 August 2002 Abstract Optical heterodyne detected optical Kerr effect (OHD experimentally using techniques such as optical Kerr effect [4­6], depolarized light scatter- ing [7], dynamic are compared to those for three other liquid crystals. The 8CB data display a short time scale temperature

Fayer, Michael D.

186

Neural network involved in time perception: An fMRI study comparing long and short interval estimation  

Microsoft Academic Search

In this study, long (1,300 ms) and short duration (450 ms) estimation trials in an event- related functional MRI (fMRI) study were contrasted in order to reveal the regions within a time estimation network yielding increased activation with the increase of the duration to be estimated. In accordance with numerous imaging studies, our results showed that the presupplementary motor area

Viviane Pouthas; Nathalie George; Jean-Baptiste Poline; Micha Pfeuty; Pierre-François VandeMoorteele; Laurent Hugueville; Anne-Marie Ferrandez; S. Lehéricy; Denis LeBihan; Bernard Renault

2005-01-01

187

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

Microsoft Academic Search

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

Christos T. Maravelias; Ignacio E. Grossmann

2003-01-01

188

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

189

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

190

Relapse revisited  

Microsoft Academic Search

Rather little is known about the changes in orthodontic treatment results exceeding a decade after treatment. The purpose of this study was to quantify changes in tooth relationships in a series of cases (n = 36) at 6 years and again at 15 years after treatment. The rate of change decreased with time, supporting the contention that most “relapse” occurs

James L. Vaden; Edward F. Harris; Roberta L. Zeigler Gardner

1997-01-01

191

Nonequilibrium critical relaxation of structurally disordered systems in the short-time regime: Renormalization group description and computer simulation  

SciTech Connect

The influence of nonequilibrium initial states on the evolution of anisotropic systems with quenched uncorrelated structural defects at the critical point is studied. The field-theoretical description of the nonequilibrium critical behavior of 3D systems is obtained for the first time, and the dynamic critical exponent of the short-time evolution in the two-loop approximation without the use of {epsilon} expansion is calculated. The values of dynamic critical exponents calculated using the series resummation methods are compared with the results of computer simulation of nonequilibrium critical behavior of the 3D disordered Ising model in the short-time regime. It is demonstrated that the values of the critical exponents calculated in this paper are in better agreement with the results of computer simulation than the results of application of {epsilon} expansion.

Prudnikov, V. V., E-mail: prudnikv@univer.omsk.su; Prudnikov, P. V.; Kalashnikov, I. A.; Rychkov, M. V. [Omsk Dostoevsky State University (Russian Federation)

2010-02-15

192

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.

193

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

194

CRISPR revisited: structure prediction of CRISPR repeats Sita Lange1  

E-print Network

CRISPR revisited: structure prediction of CRISPR repeats Sita Lange1 , Omer S. Alkhnbashi 1 Regularly Interspaced Short Palindromic Repeats (CRISPRs), illustrated to the right. The CRISPR transcripts sequences have been found to match foreign virus or plasmid DNA. A set of CRISPR-associated (Cas) proteins

Will, Sebastian

195

The Soundex Phonetic Algorithm Revisited for SMS Text Representation  

E-print Network

The Soundex Phonetic Algorithm Revisited for SMS Text Representation David Pinto1, Darnes Vilariño1 has had a major social and technological impact such as the growing use of Short Message Services (SMS phones sending between 30 and 40 SMS at month. Hence the great importance of analyzing representation

Pinto, David Eduardo

196

Network Time Domain Transmission Line Representation for Short-Pulse Radiation by Periodic Phased Arrays  

Microsoft Academic Search

We are in the process of performing an efiective wide-band analysis for characterizing the electrodynamic behavior of phased array antennas, inflnite periodic structures, frequency selective surfaces and related applications, with emphasis on gaining physical insight into the phenomenology of short-pulse radiation. The present contribution shows the current status of our network-oriented dyadic TD GF for a planar array of sequentially

F. Capolino; L. B. Felsen; A. Della Villa

197

Response times for the CAGE, short-MAST, AUDIT, and JELLINEK alcohol scales  

Microsoft Academic Search

The CAGE alcohol screening tool has been touted as a good choice for clinical settings because of its brevity. We administered\\u000a the CAGE and three other alcohol screening instruments (the Short-MAST, AUDIT, and JELLINEK) by microcomputer to 296 clients\\u000a at a drinking driver treatment program and three of the four scales to a second sample of 270 clients from six

Ron D. Hays; Laural Hill; James J. Gillogly; Matthew W. Lewis; Robert M. Bell; Ronald Nicholas

1993-01-01

198

Great magnetic storms revisited  

NASA Astrophysics Data System (ADS)

In this work we revisit a very important topic of space weather the great magnetic storms Our inspiration comes from the work done by Tsurutani et al GRL 1992 in which 5 Dst -250nT geomagnetic storms were studied in terms mainly of their interplanetary origin Since 1996 the post-SOHO era we have identified a number of 18 Dst -200nT events this time with a much more complete set of observations of the sun and of the near-earth space We use data from the Large Angle and Spectrometric Coronagraph and the Extreme Ultraviolet Imaging Telescope both aboard the Solar and Heliospheric Observatory to identify the solar origin of these events Solar wind and interplanetary magnetic field from the Advanced Composition Explorer are used to study these events in terms of their interplanetary structure We also address the high energy cosmic ray modulation caused by these events using ground-based muon observations from telescope installed at the Southern Space Observatory Brazil

Dal Lago, A.; Gonzalez, W. D.; Echer, E.; Vieira, L. E. A.; Guarnieri, F. L.; Clua de Gonzalez, A. L.; da Silva, M. R.; de Lucas, A.; Schuch, N. J.

199

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

200

Tendons – time to revisit inflammation  

PubMed Central

It is currently widely accepted among clinicians that chronic tendinopathy is caused by a degenerative process devoid of inflammation. Current treatment strategies are focused on physical treatments, peritendinous or intratendinous injections of blood or blood products and interruption of painful stimuli. Results have been at best, moderately good and at worst a failure. The evidence for non-infammatory degenerative processes alone as the cause of tendinopathy is surprisingly weak. There is convincing evidence that the inflammatory response is a key component of chronic tendinopathy. Newer anti-inflammatory modalities may provide alternative potential opportunities in treating chronic tendinopathies and should be explored further. PMID:23476034

Rees, Jonathan D; Stride, Matthew; Scott, Alex

2014-01-01

201

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

Microsoft Academic Search

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

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

2003-01-01

202

Solar Wind Amplification and Distribution Invariance of Short TimeScale Geomagnetic Variability in the Auroral Zone  

Microsoft Academic Search

Using a 22--year data set of one--minute magnetometer measurements at an auroral--zone location, a statistical model of short time--scale geomagnetic fluctuations is developed and used to evaluate how geomagnetic dynamics are influenced by different solar wind controlling parameters. The functional form of the probability distribution function (PDF) that describes extreme--value minute--to--minute (greater than 2sigma ) changes in the ground magnetic

R. S. Weigel; D. N. Baker

2003-01-01

203

Effect of short-time aerobic digestion on bioflocculation of extracellular polymeric substances from waste activated sludge.  

PubMed

The effect of short-time aerobic digestion on bioflocculation of extracellular polymeric substances (EPSs) from waste activated sludge (WAS) was investigated. Bioflocculation of the EPS was found to be enhanced by 2?6 h of WAS aerobic digestion under the conditions of natural sludge pH (about 7), high sludge concentration by gravity thickening, and dissolved oxygen of about 2 mg/L. With the same EPS extraction method, the total suspended solid content reduction of 0.20 and 0.36 g/L and the volatile suspended solid content reduction of 0.19 and 0.26 g/L were found for the WAS samples before and after aerobic digestion of 4 h. It indicates that more EPS is produced by short-time aerobic digestion of WAS. The scanning electron microscopy images of the WAS samples before and after aerobic digestion of 4 h showed that more EPS appeared on the surface of zoogloea by aerobic digestion, which reconfirmed that WAS aerobic digestion induced abundant formation of EPS. By WAS aerobic digestion, the flocculating rate of the EPS showed about 31 % growth, almost consistent with the growth of its yield (about 34 %). The EPSs obtained before and after the aerobic digestion presented nearly the same components, structures, and Fourier transform infrared spectra. These results revealed that short-time aerobic digestion of WAS enhanced the flocculation of the EPS by promoting its production. PMID:23771440

Zhang, Zhiqiang; Zhang, Jiao; Zhao, Jianfu; Xia, Siqing

2015-02-01

204

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

SciTech Connect

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

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

1993-01-01

205

Short Running Title Towards Reusable Real-Time Objects Contact Author Brian Nielsen  

E-print Network

such construction. Because real-time systems are safety critical and often unattended, they must operate under@cs.uiuc.edu http://osl.cs.uiuc.edu #12;Abstract Large and complex real-time systems can bene t signi cantly from the synchronizers to execute the system. ii #12;Nielsen and Agha, Towards Reusable Real-Time Objects 1 MOTIVATION

Nielsen, Brian

206

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

207

Short-term information pattern in optokinetic nystagmus amplitude time series.  

PubMed

In this paper we analyzed optokinetic nystagmus (OKN) signals for underlying information patterns. Fourteen OKN signals were recorded in five healthy subjects. First, we tested the correlation between nystagmus slow and fast phases. Previously, it has been suggested that the correlation is higher between the amplitude of the slow phase and the following fast phase, compared to the correlation between the fast phase and the following slow phase. However, we found no such difference. This is in agreement with the view that the saccade performed by the eye is not determined by the previous slow phase, but is free to move voluntarily in order to focus on an object of interest. Second, we analyzed the information entropy contained in the sequence of optokinetic nystagmus amplitudes, and found a short-term information pattern. Further analysis of these patterns could eventually lead to more knowledge about the vestibular and oculomotor systems. PMID:23788134

Aasen, T; Goplen, F; Nordahl, S H G

2013-01-01

208

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

209

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

PubMed

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

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

2002-12-01

210

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

211

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

212

Precise Point Positioning technique for short and long baselines time transfer  

NASA Astrophysics Data System (ADS)

In this work the clock parameters determination of several timing receivers TTS-4 (AOS), ASHTECH Z-XII3T (OP, ORB, PTB, USNO) and SEPTENTRIO POLARX4TR (ORB, since February 11, 2012) by use of the Precise Point Positioning (PPP) technique were presented. The clock parameters were determined for several time links based on the data delivered by time and frequency laboratories mentioned above. The computations cover the period from January 1 to December 31, 2012 and were performed in two modes with 7-day and one-month solution for all links. All RINEX data files which include phase and code GPS data were recorded in 30-second intervals. All calculations were performed by means of Natural Resource Canada's GPS Precise Point Positioning (GPS-PPP) software based on high-quality precise satellite coordinates and satellite clock delivered by IGS as the final products. The used independent PPP technique is a very powerful and simple method which allows for better control of antenna positions in AOS and a verification of other time transfer techniques like GPS CV, GLONASS CV and TWSTFT. The PPP technique is also a very good alternative for calibration of a glass fiber link PL-AOS realized at present by AOS. Currently PPP technique is one of the main time transfer methods used at AOS what considerably improve and strengthen the quality of the Polish time scales UTC(AOS), UTC(PL), and TA(PL). KEY-WORDS: Precise Point Positioning, time transfer, IGS products, GNSS, time scales.

Lejba, Pawel; Nawrocki, Jerzy; Lemanski, Dariusz; Foks-Ryznar, Anna; Nogas, Pawel; Dunst, Piotr

2013-04-01

213

A time-of-flight spectrometer using short heavy ion pulses  

NASA Astrophysics Data System (ADS)

A time-of-flight spectrometer consisting of a rebuncher (START signal) and selected surface barrier detectors (STOP signal) has been tested at the Heidelberg post-accelerator. Using the reaction 32S + 27Al in an incident energy range of ELab = 140-320 MeV a time resolution of ?t ˜ 70 ps was routinely achieved. This resulted in a mass resolution for medium-heavy reaction products ( m ? 60 u) of ?m ? 0.5 u.

Kolb, B.; Hlawatsch, G.; Rosner, G.; Walcher, Th.; Ingwersen, H.; Jaeschke, E.; Repnow, R.

214

Eclipse Timing Variations of Short-Period Binaries in the Kepler Field  

NASA Astrophysics Data System (ADS)

2165 eclipsing binaries in the Kepler field have been identified and characterized by Prsa et al. (2011) and Slawson et al. (2011). Due to Kepler's essentially uninterrupted observing, we are presented with an opportunity to precisely measure eclipse timings and detect any underlying signals due to third bodies, apsidal motion, dynamical interaction, etc. Orosz et al. (2012; in prep.) are focusing on eclipse timing variations of binaries with periods longer than about 1 day. For shorter period binaries, Kepler's 30 minute exposure time causes significant smearing of lightcurves and may induce spurious signal for binaries of near-commensurate periods. These effects, along with imperfections in the detrending process, can result in systematic artifacts. To compute eclipse timing variations, we fit a polynomial chain to the phased lightcurve data and slide this function across each eclipse to find the corresponding time that minimizes the residuals. We tested this method on synthetic data and apply it to Kepler data. We present statistical results on eclipse timings and discuss our findings. This project is supported through the Kepler Participating Scientist Award NSR303065.

Conroy, Kyle E.; Prsa, A.; Orosz, J.; Welsh, W.; Kepler Team

2012-05-01

215

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

216

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

217

Numerical study of the short pre-arcing time in high breaking capacity fuses via an enthalpy formulation  

NASA Astrophysics Data System (ADS)

In order to study the short pre-arcing time in high breaking capacity (HBC) fuses, we use a mathematical model including the phase change of the fuse-element heating coupled with the Laplace equation for the potential and Ohm's law. The thermal model is based on the enthalpy formulation of the heat equation with a source term representing the Joule heating. For the time range considered (up to 10 ms), we assume no heat transfer between the fuse-element and the surrounding sand. To solve numerically the governing equations, we employ a semi-implicit scheme for time integration and a finite element method for space discretization. Using electrical and thermal properties of the silver fuse-element, we present pre-arcing characteristics (temperature, current density, potential) for a fuse-element used in industrial protection circuits.

Rochette, David; Touzani, Rachid; Bussière, William

2007-08-01

218

Short contact time direct coal liquefaction using a novel batch reactor. Progress report, January 1, 1994--May 15, 1994  

SciTech Connect

The objective for this research is to optimize the design and operation of the bench scale batch reactor (SCTBR) for coal liquefaction at short contact times (0.01 to 10 minutes or longer). This reactor is simple enough and low enough in cost to serve as a suitable replacement for the traditional tubing-bomb reactors for many coal liquefaction and other high-pressure, high-temperature reaction studies. The liquefaction of selected Argonne Premium coals and the role of organic oxygen components of the coal and their reaction pathways at very low conversions are being investigated.

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

1994-05-31

219

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

220

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

221

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

222

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

223

Bohr's Atomic Model Revisited  

Microsoft Academic Search

Bohr's atomic model, its relationship to the radiation spectrum of the hydrogen atom and the inherent hypotheses are revisited. It is argued that Bohr could have adopted a different approach, focusing his analyzes on the stationary orbit of the electron and its decomposition on two harmonic oscillators and then imposing, as actually he did, Planck's quantization for the oscillators' energies.

Francisco Caruso; Vitor Oguri

2009-01-01

224

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

225

Adolescent hallux valgus revisited.  

PubMed

Treatment of adolescent hallux valgus with first metatarsal double osteotomy is well described in the literature. Unfortunately, first metatarsal phalangeal joint stiffness and deformity recurrence have been reported at relatively high rates. The authors revisit a technique aimed at preventing these complications. PMID:25102495

Marshall, Tyler J; Shung, Joseph R; Khoury, Joseph G

2014-08-01

226

Revisiting the Rhetorical Curriculum  

ERIC Educational Resources Information Center

The aim of the special strand on "Revisiting the rhetorical curriculum" is to explore the educational potential of a new rhetorical perspective, specifically in relation to different traditions within educational and rhetorical studies. This implies that we do not only look at education "in" rhetoric, but that we position education also "as" a…

Rutten, Kris; Soetaert, Ronald

2012-01-01

227

The Linguistic Repertoire Revisited  

ERIC Educational Resources Information Center

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

Busch, Brigitta

2012-01-01

228

Non-Markovian spin transfer dynamics in magnetic semiconductors despite short memory times  

NASA Astrophysics Data System (ADS)

A quantum kinetic theory of the spin transfer between carriers and Mn atoms in a Mn-doped diluted magnetic semiconductor is presented. It turns out that the typical memory time associated with these processes is orders of magnitude shorter than the time scale of the spin transfer. Nevertheless, Markovian rate equations, which are obtained by neglecting the memory, work well only for bulk systems. For quantum wells and wires the quantum kinetic results qualitatively deviate from the Markovian limit under certain conditions. Instead of a monotonic decay of an initially prepared excess electron spin, an overshoot or even coherent oscillations are found. It is demonstrated that these features are caused by energetic redistributions of the carriers due to the energy-time uncertainty.

Thurn, C.; Cygorek, M.; Axt, V. M.; Kuhn, T.

2013-05-01

229

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

230

Short-Term Storage of Semen of Rainbow Trout: Interactions of Time, Antibiotic, and Activator  

Microsoft Academic Search

This study was designed to examine the main effects and interactions of time, presence of antibiotics, and type of sperm activators on the fertilization capacity (eyeing rate) of refrigerated semen of rainbow trout, Oncorhynchus mykiss. The semen samples were stored in the presence or absence of 250 IU ml penicillin and 250 ?g ml streptomycin sulfate. Freshwater and a saline

Hamid Niksirat; Koorosh Sarvi; Asghar Abdoli; Saeed Hajirezaee

2011-01-01

231

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

E-print Network

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

Kurien, Susan

232

Stochastic Dynamic Modeling of Short Gene Expression Time-Series Data  

Microsoft Academic Search

In this paper, the expectation maximization (EM) algorithm is applied for modeling the gene regulatory network from gene time-series data. The gene regulatory network is viewed as a stochastic dynamic model, which consists of the noisy gene measurement from microarray and the gene regulation first-order autoregressive (AR) stochastic dynamic process. By using the EM algorithm, both the model parameters and

Zidong Wang; Fuwen Yang; D aniel W. C. Ho; Stephen Swift; Allan Tucker; Xiaohui Liu

2008-01-01

233

Autocorrelation Effects on Least-Squares Intervention Analysis of Short Time Series.  

ERIC Educational Resources Information Center

Clarifies several issues regarding the effects of autocorrelated errors on Type I error in ordinary least-squares models. Demonstrates through Monte Carlo simulation the conditions under which distortion in Type I error is less than predicted by asymptotic theory. Suggests a recently developed small-sample method for time-series analyses. (SLD)

Huitema, Bradley E.; McKean, Joseph W.; McKnight, Scott

1999-01-01

234

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

E-print Network

. The results show that an integrated X-ray intensity can indeed be used to evidence the irradiation effects with a broad spectrum of energies. These secondary particles can be e.g. neutrons, electrons, protons or X-rays trajectories have been analysed by calculating their X-ray diffraction patterns as a function of time

Boyer, Edmond

235

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

236

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

237

Short dissipation times of proto-planetary discs - an artifact of selection effects?  

E-print Network

The frequency of discs 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 disc frequency decreases rapidly with cluster age with 3Myr only stars that originally populated the densest areas of very populous clusters, which are prone to disc erosion, are actually considered. This tiny sample may not be representative of the majority of stars. In fact, the higher disc fractions in co-moving groups indicate that it is likely that over 30% of all field stars retain their discs 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; Menten, Karl

2014-01-01

238

Can short time delays influence the variability of the solar cycle?  

NASA Astrophysics Data System (ADS)

We present the effects of introducing results of 3D MHD simulations of buoyant magnetic fields in the solar convection zone in 2D mean-field Babcock-Leighton models. In particular, we take into account the time delay introduced by the rise time of the toroidal structures from the base of the convection zone to the solar surface. We find that the delays produce large temporal modulation of the cycle amplitude even when strong and thus rapidly rising flux tubes are considered. The study of a reduced model reveals that aperiodic modulations of the solar cycle appear after a sequence of period doubling bifurcations typical of non-linear systems. We also discuss the memory of such systems and the conclusions which may be drawn concerning the actual solar cycle variability.

Jouve, Laurène; Proctor, Michael R. E.; Lesur, Geoffroy

2011-08-01

239

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

NASA Technical Reports Server (NTRS)

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.

1986-01-01

240

Applications of short space-time fourier analysis in digital acoustics  

Microsoft Academic Search

This paper presents a signal processing tool for analyzing and manipulating digitized acoustic wave fields, based on a spatio-temporal extension of the time–frequency representation space. The emphasis is on wave fields acquired with a 1-D linear array of equidistant microphones (representing the spatial samples), but the basic formulation is valid for the three dimensions of space. We start by defining

Francisco Pinto; Martin Vetterli

2011-01-01

241

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

242

Optimal Short-Time Acquisition Schemes in High Angular Resolution Diffusion-Weighted Imaging  

PubMed Central

This work investigates the possibilities of applying high-angular-resolution-diffusion-imaging- (HARDI-) based methods in a clinical setting by investigating the performance of non-Gaussian diffusion probability density function (PDF) estimation for a range of b-values and diffusion gradient direction tables. It does so at realistic SNR levels achievable in limited time on a high-performance 3T system for the whole human brain in vivo. We use both computational simulations and in vivo brain scans to quantify the angular resolution of two selected reconstruction methods: Q-ball imaging and the diffusion orientation transform. We propose a new analytical solution to the ODF derived from the DOT. Both techniques are analytical decomposition approaches that require identical acquisition and modest postprocessing times and, given the proposed modifications of the DOT, can be analyzed in a similar fashion. We find that an optimal HARDI protocol given a stringent time constraint (<10?min) combines a moderate b-value (around 2000?s/mm2) with a relatively low number of acquired directions (>48). Our findings generalize to other methods and additional improvements in MR acquisition techniques. PMID:23554808

Pr?kovska, V.; Achterberg, H. C.; Bastiani, M.; Pullens, P.; Balmashnova, E.; ter Haar Romeny, B. M.; Vilanova, A.; Roebroeck, A.

2013-01-01

243

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

244

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

PubMed

NaP zeolite nano crystals were synthesized by sonochemical method at room temperature with crystallization time of 3h. For comparison, to insure the effect of sonochemical method, the hydrothermal method at conventional synthesis condition, with same initial sol composition was studied. NaP zeolites are directly formed by ultrasonic treatment without the application of autogenous pressure and also hydrothermal treatment. The effect of ultrasonic energy and irradiation time showed that with increasing sonication energy, the crystallinity of the powders decreased but phase purity remain unchanged. The synthesized powders were characterized by XRD, IR, DTA TGA, FESEM, and TEM analysis. FESEM images revealed that 50 nm zeolite crystals were formed at room temperature by using sonochemical method. However, agglomerated particles having cactus/cabbage like structure was obtained by sonochemical method followed by hydrothermal treatment. In sonochemical process, formation of cavitation and the collapsing of bubbles produced huge energy which is sufficient for crystallization of zeolite compared to that supplied by hydrothermal process for conventional synthesis. With increasing irradiation energy and time, the crystallinity of the synthesized zeolite samples increased slightly. PMID:22922038

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

2013-01-01

245

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

E-print Network

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

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

2008-01-17

246

Are short-time variations of the solar S-component emission identical with microwave bursts?  

NASA Astrophysics Data System (ADS)

Extended time series (time resolution about 2-3 min) of spatially resolved observations (>= 17 arcsec) in one dimension of solar S-component sources obtained at the Siberian Solar Radio Telescope (SSRT) at 5.2 cm wavelength allow the detection of evolutional features of the growth and decay of active regions in the solar corona. Characteristic slow flux variations with timescales of about 1-2 hours occurring during the decay phase of the radio emission in the low corona above plages and sunspots are compared with recently detected step-like flux increases on timescales of about 10-20 min followed by quasi-constant periods appearing in the initial phase of the development of active regions. Superimposed on this basic behaviour, also fluctuations at shorter timescales (or even periodic oscillations) have been observed. As it is well knows from emission-model calculations, the variations of the S-component radiation can be due to variations of the magnetic field an/or changes of the energy of the radiating particles, which is basically the same emission mechanism as for microwave bursts. Since the "S-component" is originally defined by its long timescale behaviour derived from whole-Sun flux density measurements, the presently detected small-timecale features in S-component sources require either a revised definition of S-component emission or must be considered as "burst-like".

Nefedev, V. P.; Smolkov, G. Ya.; Agalakov, B. V.; Kruger, A.; Hildebrandt, J.

1997-08-01

247

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.

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

2015-01-01

248

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

PubMed

Nutrient sensors that can be located directly in the activated sludge processes are gaining in number at wastewater treatment plants. The in situ location of the sensors means that they can be located close to the processes that they aim to control and hence are perfectly suited for automatic process control. Compared to the location of automatic analysers in the effluent from the sedimentation reactors the in situ location means a large reduction in the response time. The settlers typically work as a first-order delay on the signal with a retention time in the range of 4-12 hours depending on the size of the settlers. Automatic process control of the nitrogen and phosphorus removal processes means that considerable improvements in the performance of aeration, internal recirculation, carbon dosage and phosphate precipitation dosage can be reached by using a simple control structure as well as simple PID controllers. The performance improvements can be seen in decreased energy and chemicals consumption and less variation in effluent concentrations of ammonium, total nitrogen and phosphate. Simple control schemes are demonstrated for the pre-denitrification and the post precipitation system by means of full-scale plant experiments and model simulations. PMID:12926625

Ingildsen, P; Wendelboe, H

2003-01-01

249

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

250

Observation of Brownian motion in liquids at short times: instantaneous velocity and memory loss.  

PubMed

Measurement of the instantaneous velocity of Brownian motion of suspended particles in liquid probes the microscopic foundations of statistical mechanics in soft condensed matter. However, instantaneous velocity has eluded experimental observation for more than a century since Einstein's prediction of the small length and time scales involved. We report shot-noise-limited, high-bandwidth measurements of Brownian motion of micrometer-sized beads suspended in water and acetone by an optical tweezer. We observe the hydrodynamic instantaneous velocity of Brownian motion in a liquid, which follows a modified energy equipartition theorem that accounts for the kinetic energy of the fluid displaced by the moving bead. We also observe an anticorrelated thermal force, which is conventionally assumed to be uncorrelated. PMID:24675957

Kheifets, Simon; Simha, Akarsh; Melin, Kevin; Li, Tongcang; Raizen, Mark G

2014-03-28

251

Short-time hydrothermal synthesis and delamination of ion exchangeable Mg/Ga layered double hydroxides  

NASA Astrophysics Data System (ADS)

The hydrothermal synthesis of magnesium-gallium layered double hydroxides (Mg/Ga LDHs) was studied under static and agitated conditions. Not only well-crystallized and large-sized Mg/Ga LDHs having hexagonal morphology were obtained but also the reaction time was comparatively decreased from 24 to 2 h by means of agitation during hydrothermal synthesis. In static conditions, mainly GaOOH and magnesite phases were formed. The elemental analysis results show that the final Mg/Ga ratio is significantly different from the initial ratio. The reason was attributed to the difference in the hydrolytic behavior of Mg 2+ and Ga 3+. Furthermore, the anion exchange studies with glycine, dodecyl sulfate, ferrocyanide and ferricyanide were performed to investigate the intercalation behavior of the anions into Mg/Ga LDHs. In addition, delamination of Mg/Ga LDHs was performed in formamide for the glycine exchanged forms. Large size of nanosheets thus obtained can be utilized in the fabrication of functional thin films.

Unal, Ugur

2007-09-01

252

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

253

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

254

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

SciTech Connect

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

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

2006-02-10

255

Bohr's atomic model revisited  

E-print Network

Bohr's atomic model, its relationship to the radiation spectrum of the hydrogen atom and the inherent hypotheses are revisited. It is argued that Bohr could have adopted a different approach, focusing his analyzes on the stationary orbit of the electron and its decomposition on two harmonic oscillators and then imposing, as actually he did, Planck's quantization for the oscillators' energies. Some consequences of this procedure are examined.

Caruso, Francisco

2008-01-01

256

Bohr's atomic model revisited  

E-print Network

Bohr's atomic model, its relationship to the radiation spectrum of the hydrogen atom and the inherent hypotheses are revisited. It is argued that Bohr could have adopted a different approach, focusing his analyzes on the stationary orbit of the electron and its decomposition on two harmonic oscillators and then imposing, as actually he did, Planck's quantization for the oscillators' energies. Some consequences of this procedure are examined.

Francisco Caruso; Vitor Oguri

2008-06-03

257

Comparison of 3.0 T Proton Magnetic Resonance Spectroscopy Short and Long Echo-Time Measures of Intramyocellular Lipids in Obese and Normal-Weight Women  

PubMed Central

Purpose To compare correlations of intramyocellular lipids (IMCL) measured by short and long echo-time proton magnetic resonance spectroscopy (1H-MRS) with indices of body composition and insulin resistance in obese and normal-weight women. Materials and Methods We quantified IMCL of tibialis anterior (TA) and soleus (SOL) muscles in 52 premenopausal women (37 obese and 15 normal weight) using single-voxel 1H-MRS PRESS at 3.0 T with short (30 msec) and long (144 msec) echo times. Statistical analyses were performed to determine correlations of IMCL with body composition as determined by computed tomography (CT) and insulin resistance indices and to compare correlation coefficients from short and long echo-time data. Signal-to-noise ratio (SNR), linewidth, and coefficients of variation (CV) of short and long echo-time spectra were calculated. Results Short and long echo-time IMCL from TA and SOL significantly correlated with body mass index (BMI) and abdominal fat depots (r = 0.32 to 0.70, P = <0.05), liver density (r = ?0.39 to ?0.50, P < 0.05), and glucose area under the curve as a measure of insulin resistance (r = 0.47 to 0.49, P < 0.05). There was no significant difference between correlation coefficients of short and long echo-time spectra (P > 0.5). Short echo-time IMCL in both muscles showed significantly higher SNR (P < 0.0001) and lower CVs when compared to long echo-time acquisitions. Linewidth measures were not significantly different between groups. Conclusion IMCL quantification using short and long echo-time 1H-MRS at 3.0 T is useful to detect differences in muscle lipid content in obese and normal-weight subjects. In addition, IMCL correlates with body composition and markers of insulin resistance in this population with no significant difference in correlations between short and long echo-times. Short echo-time IMCL quantification of TA and SOL muscles at 3.0 T was superior to long echo-time due to better SNR and better reproducibility. PMID:20677267

Bredella, Miriam A.; Ghomi, Reza Hosseini; Thomas, Bijoy J.; Miller, Karen K.; Torriani, Martin

2013-01-01

258

Implementing high-temperature short-time media treatment in commercial-scale cell culture manufacturing processes.  

PubMed

The production of therapeutic proteins by mammalian cell culture is complex and sets high requirements for process, facility, and equipment design, as well as rigorous regulatory and quality standards. One particular point of concern and significant risk to supply chain is the susceptibility to contamination such as bacteria, fungi, mycoplasma, and viruses. Several technologies have been developed to create barriers for these agents to enter the process, e.g. filtration, UV inactivation, and temperature inactivation. However, if not implemented during development of the manufacturing process, these types of process changes can have significant impact on process performance if not managed appropriately. This article describes the implementation of the high-temperature short-time (HTST) treatment of cell culture media as an additional safety barrier against adventitious agents during the transfer of a large-scale commercial cell culture manufacturing process. The necessary steps and experiments, as well as subsequent results during qualification runs and routine manufacturing, are shown. PMID:24362912

Pohlscheidt, Michael; Charaniya, Salim; Kulenovic, Fikret; Corrales, Mahalia; Shiratori, Masaru; Bourret, Justin; Meier, Steven; Fallon, Eric; Kiss, Robert

2014-04-01

259

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

NASA Astrophysics Data System (ADS)

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

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

2005-06-01

260

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

NASA Astrophysics Data System (ADS)

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

Baku?a, M.

261

Seasonal comparisons of meteorological and agricultural drought indices in Morocco using open short time-series data  

NASA Astrophysics Data System (ADS)

Although the preliminary investigations of NDWI demonstrated its sensitivity to vegetation water content, drought indices based on NDWI short time-series are still understudied compared to those derived from NDVI and LST, such as VCI, SVI and TCI. On the basis of the open data, this paper introduces a new index derived from NDWI short time-series, and explores its performance for drought monitoring in Mediterranean semi-arid area. The new index, Standardized Water Index (SWI), was calculated and spatiotemporally compared to both meteorological drought index (TRMM-based SPI) and to agricultural drought index (NDVI-based SVI) for the hydrological years and autumn, winter and spring seasons during a period of 15 years (1998-2012). Furthermore, the response and spatial agreement of the meteorological and agricultural drought indices (SWI, SVI and SPI) were compared over two land use classes, rainfed agriculture and vegetation cover, for the studied years and seasons. The validation of SWI was based on in situ SPI and cereal productions. The analysis of the 336 cross-tables, proportions of concordance and Cohen's kappa coefficients indicate that SWI and SVI are concordant comparing to other combinations for hydrological years and for the three seasons. The study points that the spatial agreements of drought indices over rainfed agriculture and over vegetation cover are different. It is relatively more important in the rainfed agriculture than in the vegetation cover areas. Our results show that the agreement between vegetation drought indices and meteorological drought indices is moderated to low and the SPI is slightly more concordant with SWI when it is compared to SVI in autumn and winter seasons. The validation approach indicates that drought affected area, according to SWI, is highly correlated with cereal production. Likewise, a satisfactory correlation was revealed between SWI and in situ SPI.

Ezzine, Hicham; Bouziane, Ahmed; Ouazar, Driss

2014-02-01

262

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

PubMed Central

Bone contains a significant fraction of water that is not detectable with ordinary Cartesian imaging sequences. The advent of ultra-short echo-time (UTE) methods has allowed the recovery of this submillisecond T2*water. In this work, we have developed a new three-dimensional hybrid-radial ultra-short echo-time (3D HRUTE) imaging technique based on slab selection by means of half-sinc pulses, variable-TE slice encoding and algorithms for quantification. The protocol consists of collecting two datasets differing in TR, from which T1 is extracted, which is needed for quantification. Unlike T2*, which has been found to vary within a narrow range and does not require individual correction, T1 is critically subject dependent (range, 100–350 ms). No soft-tissue suppression was used to preserve the signal-to-noise ratio of the short-T2 bone water protons or to minimize the loss of relatively mobile water in large pores. Critical for quantification is correction for spatial variations in reception field and selection of the endosteal boundary for inclusion of pixels in the bone water calculation, because of the ruffled boundary stemming from trabecularization of the endosteal surface. The reproducibility, evaluated in 10 subjects covering the age range 30–80 years, yielded an average coefficient of variation of 4.2% and an intraclass correlation coefficient of 0.95, suggesting that a treatment effect on the order of 5% could be detected in as few as 10 subjects. Lastly, experiments in specimens by means of graded deuterium exchange showed that approximately 90% of the detected signal arises from water protons, whose relaxation rates (1/T1 and 1/T2*) scale linearly with the isotopic volume fraction of light water after stepwise exchange with heavy water. The data thus show conclusively that the method quantifies water even though, in vivo, no distinction can be made between various fractions, such as collagen-bound vs pore-resident water. PMID:21274960

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

2013-01-01

263

Finite frequency tomography: the checkerboard test revisited  

NASA Astrophysics Data System (ADS)

We address some consequences of the application of finite frequency theory for seismic tomography by revisiting the classical checkerboard test. We use a simple borehole-to-borehole experiment set-up in order to have complete control of the situation and to avoid complicating factors such as crustal corrections that still hamper global tomography. We are particularly interested in the feasibility of using ray-based finite frequency kernels in the inversion of travel time perturbations measured by crosscorrelation, in the cross-dependence between S wave velocity perturbations and the measured P travel times, and in the benefits of using finite-frequency theory on one or multiple frequency bands. We have done a 3D checkerboard test to assess the influence of these issues. Full-waveform synthetic seismograms are calculated using the spectral elements method up to 2 kHz maximum frequency. The computational domain extends 200 m x 120 m x 120 m and the target velocity model is a checkerboard with 12 m x 12 m x 12 m blocks of velocities 5% slower and faster than the background (homogeneous, Vp=6 km/s) model. First, we make a comparison between finite-frequency kernels calculated by ray theory with those based on the spectral elements method (adjoint technique), in terms of resolution, accuracy, but also computational cost. From synthetic seismograms calculated for the 3D checkerboard model as well as for the homogeneous model, we measure crosscorrelation travel times at different frequency bands and invert them with classical ray theory as well as with finite frequency theory. Several interesting features are highlighted in our multi-band data set, such as the wavefront healing effect. For instance, we observe that the delay times, in absolute value, are usually larger at short (0.5 ms) than long (4 ms) periods. This can be explained by the presence of the "doughnut hole" along the geometrical ray path in the sensitivity kernels, whose diameter is proportional to the period. Thus, as the period increases, the anomalies are able to "hide" inside the growing "doughnut hole". When a single frequency band is interpreted using ray theory (infinite frequency approximation), the fact that wavefront healing is not taken into account has a disastrous effect, in particular on the imaging of blocks that are somewhat smaller than the Fresnel zone. When interpreting the same data set with finite-frequency theory we do much better, especially in the center of the model where Fresnel zones are widest. Adding a range of frequencies in the inversion (i.e. taking body wave dispersion into account) significantly increases resolution.

Mercerat, E. D.; Zaroli, C.; Nolet, G.

2011-12-01

264

Sodium magnetic resonance imaging using ultra-short echo time sequences with anisotropic resolution and uniform k-space sampling.  

PubMed

A method for uniform k-space sampling of 3D ultra-short echo time (UTE) techniques with anisotropic resolution in one direction is introduced to increase signal-to-noise ratio (SNR). State-of-the-art acquisition schemes for sodium MRI with radial (projection reconstruction) and twisting (twisted projection imaging (TPI)) trajectories are investigated regarding SNR efficiency, blurring behavior under T2(?) decay, and measurement time in case of anisotropic field-of-view and resolution. 3D radial and twisting trajectories are redistributed in k-space for UTE sodium MRI with homogeneous noise distribution and optimal SNR efficiency, if T2(?) decay can be neglected. Simulations based on Voronoi tessellations and phantom simulations/measurements were performed to calculate SNR efficiency. Point-spread functions were simulated to demonstrate the influence of T2(?) decay on SNR and resolution. Phantom simulations/measurements and in vivo measurements confirm the SNR gain obtained by simulations based on Voronoi cells. An increase in SNR of up to 21% at an anisotropy factor of 10 could be theoretically achieved by TPI with projection adaption compared to the same sequence but without redistribution of projections in k-space. Sodium MRI with anisotropic resolution and uniform k-space sampling is demonstrated by in vivo measurements of human intervertebral disks and heart at 3 T. The SNR gain can be invested in a measurement time reduction of up to 32%, which is important especially for sodium MRI. PMID:25527394

Konstandin, Simon; Krämer, Philipp; Günther, Matthias; Schad, Lothar R

2015-04-01

265

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

266

Optimization of a laser ablation-inductively coupled plasma "time of flight" mass spectrometry system for short transient signal acquisition.  

PubMed

Simultaneous ion sampling and sequential detection offered by inductively coupled plasma 'time of flight' mass spectrometry (ICP-TOFMS) provides advantages for the analysis of short transient concentration-variable signals as produced in laser ablation. In order to investigate the capabilities of ICP-TOFMS in combination with an excimer laser ablation system, ablation studies on reference materials and geological samples were carried out. Various ICP-TOFMS parameters were optimized for laser-induced aerosols. Transverse rejection ion pulse was used to extend the dynamic range in concentration. A reduced volume ablation cell was designed and used in order to increase the sample density in the ICP. Results for 63 simultaneously measured isotopes (SRM 610 from NIST) lead to limits of detection in the 1-100 microg/g range for a 80 microm crater diameter (10 Hz, 1.2 mJ pulse energy). The reproducibility of signal ratios was determined to be better than 2% RSD for transient signals using 102 ms integration time. These optimized parameters were then used for the analysis of tin-rich fluid inclusions. Preliminary results of multielement analysis and isotopic ratio determinations on individual fluid inclusions (63 isotopes, 102 ms integration time) demonstrate the capabilities of ICP-TOFMS in combination with laser ablation. PMID:11220828

Bleiner, D; Hametner, K; Günther, D

2000-09-01

267

Cartilaginous End Plates: Quantitative MR Imaging with Very Short Echo Times-Orientation Dependence and Correlation with Biochemical Composition.  

PubMed

Purpose To measure the T2* of the human cartilaginous end plate by using magnetic resonance (MR) imaging with very short echo times and to determine the effect of the orientation of the end plate on T2* and on relationships between T2* and biochemical composition. Materials and Methods This study was exempt from institutional review board approval, and informed consent was not required. Thirty-four samples of three cadaveric lumbar spines (from subjects who died at ages 51, 57, and 66 years) containing cartilaginous end plates and subchondral bone were prepared. Samples were imaged with a 3-T imager for T2* quantification by using a three-dimensional very short echo time sequence (repetition time msec/echo times msec, 30/0.075, 2, 5, 12, 18). Samples were imaged with the end plate at three orientations with respect to the constant magnetic induction field: 0°, 54.7°, and 90°. After imaging, the cartilage was assayed for its water, glycosaminoglycan, and collagen content. Pearson correlations were used to investigate the effect of orientation on the relationships between T2* and biochemical composition. Results T2* was significantly longer when measured at an orientation of 54.7° (21.8 msec ± 2.8 [± standard error of the mean]) than at 0° (10.0 msec ± 0.7, P < .001) or 90° (9.9 msec ± 0.4, P < .001). At 54.7°, T2* was highly correlated with glycosaminoglycan content (r = 0.85, P < .001), the collagen-to-glycosaminoglycan ratio (r = -0.79, P < .001), and water content (r = 0.62, P = .02); at 0° and 90°, there were no significant differences in these relationships, with a minimum P value of .19. Conclusion T2* evaluation can allow noninvasive estimation of the degeneration of the cartilaginous end plate; however, the accuracy of T2*-based estimates of biochemical composition depends on the orientation of the end plate. © RSNA, 2014. PMID:25302832

Fields, Aaron J; Han, Misung; Krug, Roland; Lotz, Jeffrey C

2015-02-01

268

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.

269

Jump neural network for online short-time prediction of blood glucose from continuous monitoring sensors and meal information.  

PubMed

Several real-time short-term prediction methods, based on time-series modeling of past continuous glucose monitoring (CGM) sensor data have been proposed with the aim of allowing the patient, on the basis of predicted glucose concentration, to anticipate therapeutic decisions and improve therapy of type 1 diabetes. In this field, neural network (NN) approaches could improve prediction performance handling in their inputs additional information. In this contribution we propose a jump NN prediction algorithm (horizon 30 min) that exploits not only past CGM data but also ingested carbohydrates information. The NN is tuned on data of 10 type 1 diabetics and then assessed on 10 different subjects. Results show that predictions of glucose concentration are accurate and comparable to those obtained by a recently proposed NN approach (Zecchin et al. (2012) [26]) having higher structural and algorithmical complexity and requiring the patient to announce the meals. This strengthen the potential practical usefulness of the new jump NN approach. PMID:24192453

Zecchin, C; Facchinetti, A; Sparacino, G; Cobelli, C

2014-01-01

270

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

271

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

272

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

273

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

274

``Robinson's sum rule'' revisited  

NASA Astrophysics Data System (ADS)

This discussion revisits two articles on synchrotron radiation damping published in 1958, one by this author and Evgeny K. Tarasov [Zh. Eksp. Teor. Fiz. 34, 651 (1958)ZETFA70044-4510; Sov. Phys. JETP 34, 449 (1958)SPHJAR0038-5646], and one by Kenneth W. Robinson [Phys. Rev. 111, 373 (1958)PHRVAO0031-899X10.1103/PhysRev.111.373]. The latter is the source of what is known as “Robinson’s sum rule.” Both present the familiar rule, but with very different proofs and calculations of concrete damping decrements. Comparative analysis of these differences reveals serious flaws in Robinson’s proof and calculations.

Orlov, Yuri F.

2010-02-01

275

Multicomponent diffusion revisited  

NASA Astrophysics Data System (ADS)

The derivation of the multicomponent diffusion law is revisited. Following Furry [Am. J. Phys. 16, 63 (1948)], Williams [Am. J. Phys. 26, 467 (1958); Combustion Theory, 2nd ed. (Benjamin/Cummings , Menlo Park, CA,1985)] heuristically rederived the classical kinetic theory results using macroscopic equations, and pointed out that the dynamics of the mixture fluid had been assumed inviscid. This paper generalizes the derivation, shows that the inviscid assumption can easily be relaxed to add a new term to the classical diffusion law, and the thermal diffusion term can also be easily recovered. The nonuniqueness of the multicomponent diffusion coefficient matrix is emphasized and discussed.

Lam, S. H.

2006-07-01

276

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

277

Evidence of increased endometrial vascular permeability at the time of implantation in the short-nosed fruit bat, Cyanopterus sphinx.  

PubMed

Early embryonic development and implantation were studied in tropical short-nosed fruit bat Cyanopterus sphinx. We report preimplantation development and embryo implantation. Different stages of cleavage were observed in embryo by direct microscopic examination of fresh embryos after retrieving them either from the oviduct or the uterus at different days, up to the day of implantation. Generally, the embryos enter the uterus at the 8-cell stage. Embryonic development continued without any delay and blastocyst were formed showing attachment to the uterine epithelium at the mesometrial side of the uterus. A distinct blue band was formed in the uterus. The site of blastocyst attachment was visualized as a blue band following intravenous injection of pontamine blue. Implantation occurred 9+/-0.7 days after mating. This study reports that bat embryonic development can be studied like other laboratory animals and that this bat shows blue dye reaction, indicating the site and exact time of implantation. This blue dye reaction can be used to accurately find post-implantational delay. We prove conclusively that this species of tropical bat does not have any type of embryonic diapause. PMID:17196345

Pakrasi, Pranab Lal; Tiwari, Anjana

2007-09-01

278

Increasing lead time in short-range streamflow forecasting via the Hydrologic Ensemble Forecast Service (HEFS) (Invited)  

NASA Astrophysics Data System (ADS)

The current operational practice for short-range river forecasting at the West Gulf River Forecast Centers (WGRFC) is to input Quantitative Precipitation Forecast (QPF) out to only 12 to 24 hours (zero precipitation is assumed beyond). In the single-valued forecasting paradigm, such a practice is inevitable to avoid highly erroneous river forecasts. In the ensemble forecasting paradigm, one may input longer-lead QPF to potentially increase the lead time. In this work, we assess this potential by comparatively evaluating ensemble streamflow hindcasts forced by Day 1-3 QPF with those forced by Day 1 QPF for five headwater basins in the Upper Trinity River Basin in North Texas. The hindcasts are generated for a 7-yr period of 2004 of 2010 using the Hydrologic Ensemble Forecast Service (HEFS) which operates on the Community Hydrologic Prediction System (CHPS) of the National Weather Service (NWS). To generate ensemble QPFs from the WGRFC-produced single-valued QPFs, we used the Meteorological Ensemble Forecast Processor (MEFP). To model hydrologic uncertainty, we used the Ensemble Post-Processor (EnsPost). To verify the ensemble hindcasts, we used the Ensemble Verification System (EVS). We describe the hindcasting experiment, summarize the results and finding, and identify the issues and challenges.

Seo, D.; Saharia, M.; Corby, B.; Bell, F.

2013-12-01

279

Short-Range (0-12hr) Typhoon PQPFs from Time-Lagged Multimodel Ensembles Using LAPS in Taiwan  

NASA Astrophysics Data System (ADS)

This study pioneers the development of short-range (0-12hr) probabilistic quantitative precipitation forecasts (PQPFs) in Taiwan and aims to produce the PQPFs from time-lagged multimodel ensembles using the Local Analysis and Prediction System (LAPS). By doing so, the critical uncertainties in prediction processes can be captured and conveyed to the users. Since LAPS adopts diabatic data assimilation, it is utilized to mitigate the "spin-up" problem and produce more accurate precipitation forecasts during the early prediction stage (0-6hr). The LAPS ensemble prediction system (EPS) has a good spread-skill relationship and good discriminating ability. Therefore, though it is obviously wet-biased, the forecast biases can be corrected to improve the skill of PQPFs through a linear regression (LR) calibration procedure. Sensitivity experiments for two important factors affecting calibration results are also conducted, including: (1) the experiments on different training samples, and (2) the experiments on the accuracy of observation data. The first point reveals that the calibration results vary with training samples. Based on the statistical viewpoint, there should be enough samples for an effective calibration. Nevertheless, adopting more training samples does not necessarily produce better calibration results. It is essential to adopt training samples with similar forecast biases as validation samples to achieve better calibration results. The second factor indicates that due to the inconsistency of observation data accuracy in the sea and land areas, only separate calibration for these two areas can ensure better calibration results of the PQPFs.

Chang, Hui-Ling; Yuan, Huiling; Lin, Pay-Liam

2013-04-01

280

Effects of baroreceptor stimulation on performance of the Sternberg short-term memory task: a cardiac cycle time study.  

PubMed

Activation of arterial baroreceptors can affect cortical activity. Cardiac cycle time studies have established that natural variations in baroreceptor activation are associated with changes in basic sensorimotor function whereas few have investigated more complex cognitive function. Aiming to improve our understanding of this phenomenon, this study examined performance on the Sternberg memory task as a function of the phase of the cardiac cycle. In each trial, participants were shown either two or six digits followed by a probe digit that either had or had not been presented previously and were required to press one of two response buttons to indicate a match and mismatch, respectively. Response latency per additional digit was greater for stimuli presented late compared to early in the cardiac cycle whereas the zero intercept was greatest at the start of the cardiac cycle and reduced as the cycle progressed. These findings provide evidence that natural baroreceptor stimulation can affect complex cognitive processes, such as serial-comparison in short-term memory, as well as basic sensorimotor processes. PMID:25308911

Quelhas Martins, Amadeu; McIntyre, David; Ring, Christopher

2014-12-01

281

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

282

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 trust by enhancing the operational stability, reliability, security, and global interoperability

Schweik, Charles M.

283

Time-of-day differences and short-term stability of the neural response to monetary reward: a pilot study.  

PubMed

Human and animal studies indicate that reward function is modulated by the circadian clock that governs our daily sleep/wake rhythm. For example, a robust circadian rhythm exists in positive affect, which is lower in the morning hours and peaks in the afternoon. A handful of functional neuroimaging studies suggest that systematic diurnal variation exists in brain activity related to other functions, but no published human studies have examined daily variation in the neural processing of reward. In the present study, we attempt to advance this literature by using functional neuroimaging methods to examine time-of-day changes in the responsivity of the reward circuit. Using a within-person design and a functional magnetic resonance imaging (fMRI) monetary reward task, we compared morning and afternoon reward-related brain activation in a sample of healthy young adults within 24h. Region of interest analyses focused on the striatum, and we hypothesized greater reward activation in the afternoon, concordant with the circadian peak in positive affect. Results were consistent with our hypothesis. In addition, we counterbalanced the order of morning and afternoon scans in order to explore the short-term stability of the neural response. Whole-brain analyses showed a markedly higher reactivity to reward throughout the brain in the first scan relative to the second scan, consistent with habituation to the monetary reward stimuli. However, these effects did not appear to explain the time-of-day findings. In summary, we report the first preliminary evidence of circadian variation in the neural processing of reward. These findings have both methodological and theoretical implications. PMID:25092525

Hasler, Brant P; Forbes, Erika E; Franzen, Peter L

2014-10-30

284

FROST: Revisited and Distributed Vincent Poirriez  

E-print Network

FROST: Revisited and Distributed Vincent Poirriez LAMIH UVHC,UMR CNRS 8530 59313 Valenciennes de la Recherche FROST: Revisited and Distributed Vincent Poirriez HICOMB'05:April 04, 2005 #12;Protein Threading Problem Associate a protein sequence to an already known 3D structure. FROST: Revisited

Singer, Daniel

285

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

286

Influence of short-time imidacloprid and acetamiprid application on soil microbial metabolic activity and enzymatic activity.  

PubMed

The influence of two neonicotinoids, i.e., imidacloprid (IMI) and acetamiprid (ACE), on soil microbial activities was investigated in a short period of time using a combination of the microcalorimetric approach and enzyme tests. Thermodynamic parameters such as Q T (J g(-1) soil), ?H met (kJ mol(-1)), J Q/S (J g(-1) h(-1)), k (h(-1)), and soil enzymatic activities, dehydrogenase, phosphomonoesterase, arginine deaminase, and urease, were used to evaluate whole metabolic activity changes and acute toxicity following IMI and ACE treatment. Various profiles of thermogenic curves reflect different soil microbial activities. The microbial growth rate constant k, total heat evolution Q T (expect for IMI), and inhibitory ratio I show linear relationship with the doses of IMI and ACE. Q T for IMI increases at 0.0-20 ?g g(-1) and then decreases at 20-80 ?g g(-1), possibly attributing to the presence of tolerant microorganisms. The 50 % inhibitory ratios (IC50) of IMI and ACE are 95.7 and 77.2 ?g g(-1), respectively. ACE displays slightly higher toxicity than IMI. Plots of k and Q T against microbial biomass-C indicate that the k and Q T are growth yield-dependent. IMI and ACE show 29.6; 40.4 and 23.0; and 23.3, 21.7, and 30.5 % inhibition of dehydrogenase, phosphomonoesterase, and urease activity, respectively. By contrast, the arginine deaminase activity is enhanced by 15.2 and 13.2 % with IMI and ACE, respectively. The parametric indices selected give a quantitative dose-response relationship of both insecticides and indicate that ACE is more toxic than IMI due to their difference in molecular structures. PMID:24819438

Wang, Fei; Yao, Jun; Chen, Huilun; Yi, Zhengji; Choi, Martin M F

2014-09-01

287

Revisiting Interpretation of Canonical Correlation Analysis: A Tutorial and Demonstration of Canonical Commonality Analysis  

ERIC Educational Resources Information Center

In the face of multicollinearity, researchers face challenges interpreting canonical correlation analysis (CCA) results. Although standardized function and structure coefficients provide insight into the canonical variates produced, they fall short when researchers want to fully report canonical effects. This article revisits the interpretation of…

Nimon, Kim; Henson, Robin K.; Gates, Michael S.

2010-01-01

288

Automatic moment segmentation and peak detection analysis of heart sound pattern via short-time modified Hilbert transform.  

PubMed

This paper proposes a novel automatic method for the moment segmentation and peak detection analysis of heart sound (HS) pattern, with special attention to the characteristics of the envelopes of HS and considering the properties of the Hilbert transform (HT). The moment segmentation and peak location are accomplished in two steps. First, by applying the Viola integral waveform method in the time domain, the envelope (E(T)) of the HS signal is obtained with an emphasis on the first heart sound (S1) and the second heart sound (S2). Then, based on the characteristics of the E(T) and the properties of the HT of the convex and concave functions, a novel method, the short-time modified Hilbert transform (STMHT), is proposed to automatically locate the moment segmentation and peak points for the HS by the zero crossing points of the STMHT. A fast algorithm for calculating the STMHT of E(T) can be expressed by multiplying the E(T) by an equivalent window (W(E)). According to the range of heart beats and based on the numerical experiments and the important parameters of the STMHT, a moving window width of N=1s is validated for locating the moment segmentation and peak points for HS. The proposed moment segmentation and peak location procedure method is validated by sounds from Michigan HS database and sounds from clinical heart diseases, such as a ventricular septal defect (VSD), an aortic septal defect (ASD), Tetralogy of Fallot (TOF), rheumatic heart disease (RHD), and so on. As a result, for the sounds where S2 can be separated from S1, the average accuracies achieved for the peak of S1 (AP?), the peak of S2 (AP?), the moment segmentation points from S1 to S2 (AT??) and the cardiac cycle (ACC) are 98.53%, 98.31% and 98.36% and 97.37%, respectively. For the sounds where S1 cannot be separated from S2, the average accuracies achieved for the peak of S1 and S2 (AP??) and the cardiac cycle ACC are 100% and 96.69%. PMID:24657095

Sun, Shuping; Jiang, Zhongwei; Wang, Haibin; Fang, Yu

2014-05-01

289

Effect of short-term heat acclimation on endurance time and skin blood flow in trained athletes  

PubMed Central

Background To examine whether short-term, ie, five daily sessions, vigorous dynamic cycling exercise and heat exposure could achieve heat acclimation in trained athletes and the effect of heat acclimation on cutaneous blood flow in the active and nonactive limb. Methods Fourteen male badminton and table tennis athletes (age = 19.6 ± 1.2 years) were randomized into a heat acclimation (EXP, n = 7) or nonheat acclimation (CON, n = 7) group. For 5 consecutive days, the EXP group was trained using an upright leg cycle ergometer in a hot environment (38.4°C ± 0.4°C), while the CON group trained in a thermoneutral environment (24.1°C ± 0.3°C). For both groups, the training intensity and duration increased from a work rate of 10% below ventilatory threshold (VT) and 25 minutes per session on day 1, to 10% above VT and 45 minutes per session on day 5. Subjects performed two incremental leg cycle exercise tests to exhaustion at baseline and post-training in both hot and thermoneutral conditions. Study outcome measurements include: maximum oxygen uptake (VO2max); exercise heart rate (HR); O2 pulse; exercise time to exhaustion (tmax); skin blood flow in the upper arm (SkBFa) and quadriceps (SkBFq); and mean skin (Tsk). Results The significant heat-acclimated outcome measurements obtained during high-intensity leg cycling exercise in the high ambient environment are: (1) 56%–100% reduction in cutaneous blood flow to the active limbs during leg cycling exercise; (2) 28% drop in cutaneous blood flow in nonactive limbs at peak work rate; (3) 5%–10% reduction in heart rate (HR); (4) 10% increase in maximal O2 pulse; and (5) 6.6% increase in tmax. Conclusion Heat acclimation can be achieved with five sessions of high-intensity cycling exercise in the heat in trained athletes, and redistribution of cutaneous blood flow in the skin and exercising muscle, and enhanced cardiovascular adaptations provide the heat-acclimated athletes with the capability to increase their endurance time in the hot environment. PMID:24379721

Chen, Tsung-I; Tsai, Pu-Hsi; Lin, Jui-Hsing; Lee, Ning-Yuean; Liang, Michael TC

2013-01-01

290

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

291

Optimal filtering of dynamics in short-time features for music organization Jeronimo Arenas-Garcia, Jan Larsen, Lars Kai Hansen and Anders Meng  

E-print Network

music titles directly from Internet services such as e.g. iTunes or Napster 1 . Portable players easilyOptimal filtering of dynamics in short-time features for music organization Jer´onimo Arenas interest in customizable methods for organizing music collections. Relevant music characteriza- tion can

292

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

293

Changes in Children's Perception-Action Tuning over Short Time Scales: Bicycling across Traffic-Filled Intersections in a Virtual Environment  

ERIC Educational Resources Information Center

This investigation examined short-term changes in child and adult cyclists' gap decisions and movement timing in response to general and specific road-crossing experiences. Children (10- and 12-year-olds) and adults rode a bicycle through a virtual environment with 12 intersections. Participants faced continuous cross traffic and waited for gaps…

Plumert, Jodie M.; Kearney, Joseph K.; Cremer, James F.; Recker, Kara M.; Strutt, Jonathan

2011-01-01

294

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

295

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

296

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

297

Bulgarian ergonomics revisited.  

PubMed

In his earlier and more intensive review of ergonomics in Bulgaria, the author concluded that this discipline was highly developed and enjoyed strong government support. It was found that the network of ergonomics activities across national, regional, and local industrial plant levels was perhaps the most highly organised and comprehensive extension of ergonomics concerns of any country in the world. The brief revisit described in this report revealed that ergonomics continues to enjoy a very high measure of respectability. As also noted earlier, the field of ergonomics is still largely the province of physiologists and engineers. Some psychologists that are associated with design organisations are involved in ergonomics activities but, for the most part, psychologists deal primarily with more traditional topics that fall under the heading of industrial or work psychology. PMID:15676425

Seminara, J L

1982-03-01

298

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

299

Polite Theories Revisited  

NASA Astrophysics Data System (ADS)

The classic method of Nelson and Oppen for combining decision procedures requires the theories to be stably-infinite. Unfortunately, some important theories do not fall into this category (e.g. the theory of bit-vectors). To remedy this problem, previous work introduced the notion of polite theories. Polite theories can be combined with any other theory using an extension of the Nelson-Oppen approach. In this paper we revisit the notion of polite theories, fixing a subtle flaw in the original definition. We give a new combination theorem which specifies the degree to which politeness is preserved when combining polite theories. We also give conditions under which politeness is preserved when instantiating theories by identifying two sorts. These results lead to a more general variant of the theorem for combining multiple polite theories.

Jovanovi?, Dejan; Barrett, Clark

300

Satellite failures revisited  

NASA Astrophysics Data System (ADS)

In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.

Balcerak, Ernie

2012-12-01

301

Simultaneous improvement of strength and ductility of Al–Mg–Si alloys by combining equal-channel angular extrusion with subsequent high-temperature short-time aging  

Microsoft Academic Search

The aging behaviour after room temperature (RT) equal-channel angular extrusion (ECAE) of the pre-ECAE solid-solution treated 6060 Al alloy was investigated in wide ranges of temperature, time, and ECAE pre-strain. It is shown that high-temperature, short-time aging is most effective in improving both strength and ductility. Compared to the commercially available peak aged condition with coarse grains, an increase of

M. Hockauf; L. W. Meyer; B. Zillmann; M. Hietschold; S. Schulze; L. Krüger

2009-01-01

302

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

303

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

304

Magnetic resonance imaging (MRI) of solid materials entails numerous problems from short longitudinal relaxation (T2) times to  

E-print Network

Magnetic resonance imaging (MRI) of solid materials entails numerous problems from short advantages over conventional MRI procedures such as more stable and stronger gradients (> 50 T/m), and finer the metal foils on the 1D profile. High-Resolution MRI Probe for STRAFI Studies of Solid Materials Joel A

Weston, Ken

305

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

306

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

307

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

308

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

309

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

310

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

311

EPISTATIC INTERACTIONS OF THREE LOCI REGULATE FLOWERING TIME UNDER SHORT AND LONG DAYLENGTHS IN A BACKCROSS POPULATION OF RICE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The short-day plant rice varies greatly in photoperiod sensitivity (PS) for flowering. The hybrid F1 from a cross between the day-neutral pure line EM93-1 and the weedy rice accession SS18-2 had stronger PS than SS18-2. Some BC1 (EM93-1/ F1) segregates were even more sensitive to photoperiod than th...

312

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

313

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

314

Containment failure time and mode for a low-pressure short-term station blackout in a BWR4 with Mark-I containment  

Microsoft Academic Search

This study investigates containment failure time and mode for a low-pressure, short-term station blackout severe accident sequence in a boiling water reactor (BWR-4) with a Mark-I containment. The severe accident analysis code MELCOR, version 1.8.1, was used in these calculations. Other results using the MELCOR\\/CORBH package and the BWRSAR and CONTAIN codes are also presented and compared to the MELCOR

J. J. Carbajo; S. R. Greene

1993-01-01

315

Dark Energy Perturbations Revisited  

E-print Network

In this paper we study the evolution of cosmological perturbations in the presence of dynamical dark energy, and revisit the issue of dark energy perturbations. For a generally parameterized equation of state (EoS) such as w_D(z) = w_0+w_1\\frac{z}{1+z}, (for a single fluid or a single scalar field ) the dark energy perturbation diverges when its EoS crosses the cosmological constant boundary w_D=-1. In this paper we present a method of treating the dark energy perturbations during the crossing of the $w_D=-1$ surface by imposing matching conditions which require the induced 3-metric on the hypersurface of w_D=-1 and its extrinsic curvature to be continuous. These matching conditions have been used widely in the literature to study perturbations in various models of early universe physics, such as Inflation, the Pre-Big-Bang and Ekpyrotic scenarios, and bouncing cosmologies. In all of these cases the EoS undergoes a sudden change. Through a detailed analysis of the matching conditions, we show that \\delta_D an...

Li, Mingzhe; Li, Hong; Brandenberger, Robert; Zhang, Xinmin

2010-01-01

316

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

317

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

318

Moment tensor decompositions revisited  

NASA Astrophysics Data System (ADS)

The decomposition of moment tensors into isotropic (ISO), double-couple (DC) and compensated linear vector dipole (CLVD) components is a tool for classifying and physically interpreting seismic sources. Since an increasing quantity and quality of seismic data allow inverting for accurate moment tensors and interpreting details of the source process, an efficient and physically reasonable decomposition of moment and source tensors is necessary. In this paper, the most common moment tensor decompositions are revisited, new equivalent formulas of the decompositions are derived, suitable norms of the moment tensors are discussed and the properties of commonly used source-type plots are analysed. The Hudson skewed diamond plot is introduced in a much simpler way than originally proposed. It is shown that not only the Hudson plot but also the diamond CLVD-ISO plot and the Riedesel-Jordan plot conserve the uniform distribution probability of moment eigenvalues if the appropriate norm of moment tensors is applied. When analysing moment tensor uncertainties, no source-type plot is clearly preferable. Since the errors in the eigenvectors and eigenvalues of the moment tensors cannot be easily separated, the moment tensor uncertainties project into the source-type plots in a complicated way. As a consequence, the moment tensors with the same uncertainties project into clusters of a different size. In case of an anisotropic focal area, the complexity of moment tensors of earthquakes prevents their direct interpretation, and the decomposition of moment tensors must be substituted by that of the source tensors.

Vavry?uk, Václav

2015-01-01

319

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

320

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

321

Common Knowledge Revisited Ronald Fagin  

E-print Network

that in order for something to be a convention, it must in fact be common knowledge among the members of a group means "go" and red means "stop" is presumably common knowledge among the drivers in our society.) CommonCommon Knowledge Revisited Ronald Fagin IBM Almaden Research Center 650 Harry Road San Jose, CA

Halpern, Joseph Y.

322

Revisiting the value of pre-hospital tracheal intubation: an all time systematic literature review extracting the Utstein airway core variables  

PubMed Central

Introduction Although tracheal intubation (TI) in the pre-hospital setting is regularly carried out by emergency medical service (EMS) providers throughout the world, its value is widely debated. Heterogeneity in procedures, providers, patients, systems and stated outcomes, and inconsistency in data reporting make scientific reports difficult to interpret and compare, and the majority are of limited quality. To hunt down what is really known about the value of pre-hospital TI, we determined the rate of reported Utstein airway variables (28 core variables and 12 fixed-system variables) found in current scientific publications on pre-hospital TI. Methods We performed an all time systematic search according to the PRISMA guidelines of Medline and EMBASE to identify original research pertaining to pre-hospital TI in adult patients. Results From 1,076 identified records, 73 original papers were selected. Information was extracted according to an Utstein template for data reporting from in-the-field advanced airway management. Fifty-nine studies were from North American EMS systems. Of these, 46 (78%) described services in which non-physicians conducted TI. In 12 of the 13 non-North American EMS systems, physicians performed the pre-hospital TI. Overall, two were randomised controlled trials (RCTs), and 65 were observational studies. None of the studies presented the complete set of recommended Utstein airway variables. The median number of core variables reported was 10 (max 21, min 2, IQR 8-12), and the median number of fixed system variables was 5 (max 11, min 0, IQR 4-8). Among the most frequently reported variables were "patient category" and "service mission type", reported in 86% and 71% of the studies, respectively. Among the least-reported variables were "co-morbidity" and "type of available ventilator", both reported in 2% and 1% of the studies, respectively. Conclusions Core data required for proper interpretation of results were frequently not recorded and reported in studies investigating TI in adults. This makes it difficult to compare scientific reports, assess their validity, and extrapolate to other EMS systems. Pre-hospital TI is a complex intervention, and terminology and study design must be improved to substantiate future evidence based clinical practice. PMID:21244667

2011-01-01

323

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 and ATP synthesis. It is argued that this mechanism, based on at least 15 years of experimental and theoretical work by Sunil Nath, constitutes a fundamentally different theory of the energy conversion process that eliminates all the inconsistencies in Mitchell's chemiosmotic theory pointed out by other authors. It is concluded that the energy-transducing complexes in oxidative phosphorylation and photosynthesis are proton-dicarboxylic acid anion cotransporters and not simply electrogenic proton translocators. These results necessitate revision of previous theories of biological energy transduction, coupling, and ATP synthesis. The novel molecular mechanism is extended to cover ATP synthesis in prokaryotes, in particular to alkaliphilic and haloalkaliphilic bacteria, essentially making it a complete theory addressing mechanistic, kinetic, and thermodynamic details. Finally, based on the new interpretation of oxidative phosphorylation, quantitative values for the P/O ratio, the amount of ATP generated per redox package of the reduced substrates, are calculated and compared with experimental values for fermentation on different substrates. It is our hope that the presentation of oxidative phosphorylation and photophosphorylation from a wholly new perspective will rekindle scientific discussion of a key process in bioenergetics and catalyze new avenues of research in a truly interdisciplinary field. Biotechnol. Bioeng. 2015;112: 429-437. © 2014 Wiley Periodicals, Inc. PMID:25384602

Nath, Sunil; Villadsen, John

2015-03-01

324

The intercomparison of ozone measured from the SME and Nimbus-7 satellites on short and long time scales  

NASA Technical Reports Server (NTRS)

The spatial and temporal characteristics of ozone density measured from the SBUV (Solar Backscatter Ultraviolet) spectrometer on Nimbus-7 and the UV and the UV and the IR spectrometers on SME (Solar Mesosphere Explorer) are compared in the altitude region near 50 km where the three data sets overlap. Their temporal characteristics, when averaged over the same longitude range, are remarkably similar with respect to seasonal variations and short term fluctuations induced by transient planetary waves. The long term trends in the three data sets, however, differ significantly with each other. Over the three year period after 1982 ozone mixing ratio at 1 mb decreased by about 10 percent based on SEUV measurements but increased by 12 and 30 percent respectively based on SME-IR and SME-UV measurements. None of these estimates are consistent with the predicted decrease of about 2 percent based on solar UV flux and temperature changes during this period.

Chandra, S.; Mcpeters, R. D.; Srivastava, D. N.

1986-01-01

325

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.

326

Effort- and time-cost effects on demand curves for food by pigeons under short session closed economies.  

PubMed

Demand curves for food were compared under the effort- and time-cost conditions using response-initiated fixed-ratio (FR) and fixed-interval (FI) schedules. For the effort-cost conditions, two pigeons were exposed to FR 3, 30, 90, and 150 for six sessions each. The time equivalent of each ratio was a FI schedule, each FI value equal to an average time from the first peck on the ratio to reinforcement (3-s access to mixed grain). The experiment was repeated in 1.5-, 3.0-, and 4.5-h closed economies in a different order for each pigeon. Food consumption as a function of time-based unit price (time equivalent per reinforcement duration) for each session length showed moderate convergence on a single demand function for the two cost conditions. When the demand function was separately fitted to each cost condition, however, the ranges of inelastic demand were generally larger in time-cost than effort-cost conditions. These curve-fitting analyses suggest that although time is a critical cost factor decreasing consumption at moderate prices, food intake under the effort-cost condition decreases more rapidly than under the time-cost condition as unit price increases. The analyses provide useful descriptions for the functional difference of costs. PMID:11254991

Tsunematsu, S

2001-03-13

327

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

328

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

329

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

330

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 2010-04-01 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...

2010-04-01

331

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

332

The variability of biogenic sulfur flux from a temperate salt marsh on short time and space scales  

NASA Astrophysics Data System (ADS)

Three emission chambers were deployed simultaneously to measure rates of emission of dimethyl sulfide, methane thiol and carbonyl sulfide within or across vegetation zones in a New Hampshire salt marsh. Short term (a few hours) variation in fluxes of all S gases from replicate sites were small within a monospecific stand of either Spartina alterniflora or S. patens. The quantity of emergent biomass and the type of vegetation present were the primary factors regulating the rate of emission. Dimethyl sulfide fluxes from the S. alterniflora soils ranged from 800 to 18,000 nmol m -2 h -1 compared to emissions of 25-120 nmol m -2 h -1 from S. patens. This difference was probably due to the presence of the dimethyl-sulfide precursor dimethylsulfoniopropionate which is an osmoregulator in S. alterniflora but not in S. patens. Methane thiol emissions from S. alterniflora were 20-280 nmol m -2 h -1 and they displayed a similar diel trend as dimethyl sulfide, although at much lower rates, suggesting that methane thiol is produced primarily by leaves. Methane thiol emissions from S. patens were 20-70 nmol m -2 h -1. Net uptake of carbonyl sulfide of 25-40 nmol m -2 h -1 occurred in stands of S. alterniflora while net efflux of 10-36 nmol m -2 h -1 of carbonyl sulfide occurred in stands of S. patens. In general, ranges of emissions of sulfur gases were similar to most other published values.

Morrison, Michael C.; Hines, Mark E.

333

Time-resolved Spectroscopy and Multi-color Photometry Of The Pulsating and Short-period Binary Subdwarf B Star Feige 48  

NASA Astrophysics Data System (ADS)

Pulsating subdwarf B (sdB) stars can be used as probes of the helium fusing cores of horizontal branch stars. To probe these stars, asteroseismology must be able to observationally associate pulsation frequencies with modes. Time-resolved spectroscopy and multicolor photometry have been employed with mixed results for short-period pulsating sdB stars. Time-resolved spectroscopy has successfully measured radial velocity, temperature, and gravity variations in six pulsators, yet interpreting results is far from straightforward. Multicolor photometry requires extremely high precision to discern between low-degree modes, yet has been used effectively to eliminate high-degree modes. Combining RV and multicolor measurements has also been shows as an effective means of constraining mode identifications. I will present results for Feige 48 using both time-resolved spectroscopy and multicolor photometry and attempts to constrain their pulsation modes using the atmospheric codes BRUCE and KYLIE.

Reed, Mike; Baran, A.; O'Toole, S.

2012-05-01

334

Balance functions revisited  

E-print Network

The idea of glue clusters, i.e. short-range correlations in the quark-gluon plasma close to freeze-out, is used to estimate the width of balance functions in momentum space. A good agreement is found with the recent measurements of STAR collaboration for central $Au-Au$ collisions.

A. Bialas

2011-02-11

335

Tendons--time to revisit inflammation.  

PubMed

It is currently widely accepted among clinicians that chronic tendinopathy is caused by a degenerative process devoid of inflammation. Current treatment strategies are focused on physical treatments, peritendinous or intratendinous injections of blood or blood products and interruption of painful stimuli. Results have been at best, moderately good and at worst a failure. The evidence for non-infammatory degenerative processes alone as the cause of tendinopathy is surprisingly weak. There is convincing evidence that the inflammatory response is a key component of chronic tendinopathy. Newer anti-inflammatory modalities may provide alternative potential opportunities in treating chronic tendinopathies and should be explored further. PMID:23476034

Rees, Jonathan D; Stride, Matthew; Scott, Alex

2014-11-01

336

Mayerling Revisited: The Short Life and Death of Mary Vetsera  

Microsoft Academic Search

Amidst the dramatic background of Vienna in the 1890s, a romance quickly developed between the Crown Prince Rudolf and a young socialite, Mary Vetsera. Ultimately this romance would end in tragedy with their fateful murder suicide at Mayerling. The circumstances surrounding the Crown Prince’s death have been widely written about, but questions regarding Mary Vetsera’s motives still linger. Using the

Chelsea Ridley

2011-01-01

337

Region-time-length algorithm and its application to the study of intermediate-short term earthquake precursor in North China  

NASA Astrophysics Data System (ADS)

The Region-Time-Length Algorithm (RTL algorithm) is introduced and improved in the paper. Compared with the original definition, the influence of rupture length on RTL function is emphasized and the weights of epicentral distance function, time function, and rupture length function are ensured to be equal. The retrospective examinations of RTL algorithm in North China have indicated that the anomalies obtained by the improved RTL algorithm show the short or intermediate-short term precursory features in most cases. There are two types of RTL anomalous patterns before the main shock. For the I-type, the variation pattern of the VRTL, numerical values of the VRTL( x, y, z, t) function, is complete and most of them have shown the changing pattern of “rising from 0 “ turning “ dropping” or ”dropping from 0 ” turning ” rising”. For the II-type, the variation pattern of V RTL is not complete, which increases or decreases quickly from 0 and there is no evident turning, the main shock generally occurs in the short period around the peak VRTL. The rising of VRTL indicates an increase of seismic activity relative to the background level, which means the enhancement of seismic activity, while the dropping of V RTL indicates the decrease of seismic activity relative to the background level, which represents the seismic quiescence to a certain extent. According to statistical examination results of RTL algorithm in North China, the methods to distinguish the intermediate and short-term anomalies and to estimate the occurrence time of the coming main shock are given in the paper. For both I and II-type RTL anomalies, the R-value, i.e., the forecasting score, is about 0.6 and 0.3 for the 3 months forecasting period and about 0.7 and 0.4 for the 6 months forecasting period. The preliminary discussion is also made for the influences of characteristic time-span t0, characteristic distance r0, and threshold magnitude M 0 on computation of V RTL, as well as some other significant problems in application.

Jiang, Hai-Kun; Hou, Hai-Feng; Zhou, Huan-Peng; Zhou, Cui-Ying

2004-03-01

338

First Grade Writers Revisit Their Work  

ERIC Educational Resources Information Center

In this article, the author focuses on first grade readers and writers who revisit their work and describes what first-graders do when they revisit their writing about science and literature and review collections of their work. The first-graders discussed here are in Elaine O'Connor's classroom at Clark Elementary School in Charlottesville. In a…

Hansen, Jane A.

2007-01-01

339

Test-Retest Reliability and Reproducibility of Short-Echo-Time Spectroscopic Imaging of Human Brain at 3T  

PubMed Central

A 1H magnetic resonance spectroscopic imaging (1H-MRSI) study at 3T and short TE was conducted to evaluate both the reproducibility, as measured by the inter-scan coefficient of variation (CV), and test-retest reliability, as measured by the intraclass correlation coefficient (ICC), of measurements of glutamate (Glu), combined glutamate and glutamine (Glx), myo-inositol (mI), N-acetylaspartate (NAA), creatine, and choline in 21 healthy subjects. The effect of partial volume correction on these measures and the relationship of reproducibility and reliability to data quality were also examined. A 1H-MRSI slice was prescribed above the lateral ventricles and single repeat scans were performed within 30 min to minimize physiologic variability. Inter-scan CVs based on all the voxels varied from 0.05-0.07 for NAA, creatine, and choline to 0.10-0.13 for mI, Glu, and Glx. Findings on the reproducibility of gray and white matter estimates of NAA, creatine, and choline are consistent with previous studies using longer TEs, with CVs in the range of 0.02-0.04 and ICCs in the range of 0.65-0.90. CVs for Glu, Glx, and mI are much lower than reported in previous studies at 1.5T, while white matter mI (CV=0.04, ICC=0.93) and gray matter Glx (CV=0.04, ICC=0.68) demonstrated both high reproducibility and test-retest reliability. PMID:21360748

Gasparovic, Charles; Bedrick, Edward J.; Mayer, Andrew R; Yeo, Ronald A.; Chen, HongJi; Damaraju, Eswar; Calhoun, Vince D.; Jung, Rex E.

2011-01-01

340

SHORT STORY: \\  

Microsoft Academic Search

In teaching short story, there are lots of techniques, methods and approaches. One of these methods, especially for the students at the foreign language departments of universities, is literary approaches. Sometimes by abandoning the traditional ways of teaching short story, a trainer may make use of the literary approaches. Analyzing a short story by means of using one or more

Aysel Ünsal

341

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

E-print Network

that within the first few hundred nanoseconds upon power-on, there were fast attenuating, dispersive shock waves of extremely high frequency propagating in the package. The notions of high cycle fatigue, power density and joint time-frequency analysis were...

Oh, Yoonchan

2005-11-01

342

Short-term soil nutrient impact in a real-time drain field soil moisture controlled SDI wastewater disposal system  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Alabama Black Belt area is widespread of Vertisols that are generally unsuitable for conventional septic systems; nonetheless, systems of this type have been widely used in this region for decades. In order to explore alternatives for these conventional septic systems, a real-time soil moisture ...

343

Low-dose aspirin to pregnant women: single dose pharmacokinetics and influence of short term treatment on bleeding time.  

PubMed

Single dose pharmacokinetics of 75 mg aspirin was investigated in two groups of ten women with clinically normal pregnancies. Eleven non-pregnant subjects in the same age were controls. In group A, gestational age was 27-30 completed weeks, and in group B, 36-39 weeks. Venous blood samples were taken before and up to 240 minutes after the intake of the aspirin. Liquid chromatographic assays for acetylsalicylic acid (ASA) and its metabolite, salicylic acid (SA), was performed. The pharmacokinetics of ASA and SA were similar in group A and B but pregnant subjects had a slower uptake and a lower peak level than controls. The late elimination phase for their compound did not differ between the groups. Nine pregnant women with normal pregnancies had their bleeding time measured by a modified Ivy technique using a Simplate II device before, at the end of, and two weeks after daily administration of 75 mg ASA for two weeks. All had a normal bleeding time before and two weeks after the end of the medication. Eight of the nine subjects had an increased bleeding time by Ivy tests, (p < 0.01) whereas the bleeding time assessed by Duke's method was within normal limits. These studies suggest that during pregnancy changes of the uptake rate and distribution volume modulate the pharmacokinetics of ASA and that this drug given in low dosage to gravidae marginally alters their platelet function. PMID:7823260

Rymark, P; Berntorp, E; Nordsjö, P; Liedholm, H; Melander, A; Gennser, G

1994-01-01

344

A mode coupling theory description of the short-and long-time dynamics of nematogens in the isotropic phase  

E-print Network

January 2006 Optical heterodyne-detected optical Kerr effect OHD-OKE experimental data are pre- sented, the local order randomizes, giving rise to exponential decays of time domain optical Kerr effect experiments a noticeable effect on properties of the liquid near the phase transition temperature, TNI. LdG theory predicts

Fayer, Michael D.

345

Calcination and sintering models for application to high-temperature, short-time sulfation of calcium-based sorbents  

Microsoft Academic Search

To simulate the staged availability of transient high surface area CaO observed in high-temperature flow-reactor data, the paper describes the rate of calcination of CaCOâ or Ca(OH)2, using an empirical modification of the shrinking-core model. The physical model depicts particle decomposition by the shrinking-core mechanism. The subsequent time-dependent decrease in CaO reactivity (surface area and porosity) due to sintering is

Corey R. Milne; Geoffrey D. Silcox; David W. Pershing; David A. Kirchgessner

1990-01-01

346

Time course of lung retention and toxicity of inhaled particles: short-term exposure to nano-Ceria.  

PubMed

Two Ceria nanomaterials (NM-211 and NM-212) were tested for inhalation toxicity and organ burdens in order to design a chronic and carcinogenicity inhalation study (OECD TG No. 453). Rats inhaled aerosol concentrations of 0.5, 5, and 25 mg/m(3) by whole-body exposure for 6 h/day on 5 consecutive days for 1 or 4 weeks with a post-exposure period of 24 or 129 days, respectively. Lungs were examined by bronchoalveolar lavage and histopathology. Inhaled Ceria is deposited in the lung and cleared with a half-time of 40 days; at aerosol concentrations higher than 0.5 mg/m(3), this clearance was impaired resulting in a half-time above 200 days (25 mg/m(3)). After 5 days, Ceria (>0.5 mg/m(3)) induced an early inflammatory reaction by increases of neutrophils in the lung which decreased with time, with sustained exposure, and also after the exposure was terminated (during the post-exposure period). The neutrophil number observed in bronchoalveolar lavage fluid (BALF) was decreasing and supplemented by mononuclear cells, especially macrophages which were visible in histopathology but not in BALF. Further progression to granulomatous inflammation was observed 4 weeks post-exposure. The surface area of the particles provided a dose metrics with the best correlation of the two Ceria's inflammatory responses; hence, the inflammation appears to be directed by the particle surface rather than mass or volume in the lung. Observing the time course of lung burden and inflammation, it appears that the dose rate of particle deposition drove an initial inflammatory reaction by neutrophils. The later phase (after 4 weeks) was dominated by mononuclear cells, especially macrophages. The progression toward the subsequent granulomatous reaction was driven by the duration and amount of the particles in the lung. The further progression of the biological response will be determined in the ongoing long-term study. PMID:25273020

Keller, Jana; Wohlleben, Wendel; Ma-Hock, Lan; Strauss, Volker; Gröters, Sibylle; Küttler, Karin; Wiench, Karin; Herden, Christiane; Oberdörster, Günter; van Ravenzwaay, Bennard; Landsiedel, Robert

2014-11-01

347

Predictability of Solar Radiation for Photovoltaics systems over Europe: from short-term to seasonal time-scales  

NASA Astrophysics Data System (ADS)

Photovoltaic diffusion is steadily growing on Europe, passing from a capacity of almost 14 GWp in 2011 to 21.5 GWp in 2012 [1]. Having accurate forecast is needed for planning and operational purposes, with the possibility to model and predict solar variability at different time-scales. This study examines the predictability of daily surface solar radiation comparing ECMWF operational forecasts with CM-SAF satellite measurements on the Meteosat (MSG) full disk domain. Operational forecasts used are the IFS system up to 10 days and the System4 seasonal forecast up to three months. Forecast are analysed considering average and variance of errors, showing error maps and average on specific domains with respect to prediction lead times. In all the cases, forecasts are compared with predictions obtained using persistence and state-of-art time-series models. We can observe a wide range of errors, with the performance of forecasts dramatically affected by orography and season. Lower errors are on southern Italy and Spain, with errors on some areas consistently under 10% up to ten days during summer (JJA). Finally, we conclude the study with some insight on how to "translate" the error on solar radiation to error on solar power production using available production data from solar power plants. [1] EurObserver, "Baromètre Photovoltaïque, Le journal des énergies renouvables, April 2012."

De Felice, Matteo; Petitta, Marcello; Ruti, Paolo

2014-05-01

348

Pair Production Constraints on Superluminal Neutrinos Revisited  

SciTech Connect

We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p{sup 2} can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.

Brodsky, Stanley J.; /SLAC; Gardner, Susan; /Kentucky U.

2012-02-16

349

The parallel-antiparallel signal difference in double-wave-vector diffusion-weighted MR at short mixing times: A phase evolution perspective  

NASA Astrophysics Data System (ADS)

Experiments with two diffusion weightings applied in direct succession in a single acquisition, so-called double- or two-wave-vector diffusion-weighting (DWV) experiments at short mixing times, have been shown to be a promising tool to estimate cell or compartment sizes, e.g. in living tissue. The basic theory for such experiments predicts that the signal decays for parallel and antiparallel wave vector orientations differ by a factor of three for small wave vectors. This seems to be surprising because in standard, single-wave-vector experiments the polarity of the diffusion weighting has no influence on the signal attenuation. Thus, the question how this difference can be understood more pictorially is often raised. In this rather educational manuscript, the phase evolution during a DWV experiment for simple geometries, e.g. diffusion between parallel, impermeable planes oriented perpendicular to the wave vectors, is considered step-by-step and demonstrates how the signal difference develops. Considering the populations of the phase distributions obtained, the factor of three between the signal decays which is predicted by the theory can be reproduced. Furthermore, the intermediate signal decay for orthogonal wave vector orientations can be derived when investigating diffusion in a box. Thus, the presented “phase gymnastics” approach may help to understand the signal modulation observed in DWV experiments at short mixing times.

Finsterbusch, Jürgen

2011-01-01

350

Delayed administration of VEGF rescues spinal motor neurons from death with a short effective time frame in excitotoxic experimental models in vivo  

PubMed Central

VEGF (vascular endothelial growth factor) prevents neuronal death in different models of ALS (amyotrophic lateral sclerosis), but few studies have addressed the efficacy of VEGF to protect motor neurons after the onset of symptoms, a critical point when considering VEGF as a potential therapeutic target for ALS. We studied the capability of VEGF to protect motor neurons after an excitotoxic challenge in two models of spinal neurodegeneration in rats induced by AMPA (?-amino-3-hydroxy-5-methylisoxazole-4-propionic acid) administered either chronically with osmotic minipumps or acutely by microdialysis. VEGF was administered through osmotic minipumps in the chronic model or injected intracerebroventricularly in the acute model, and its effects were assessed by immunohistochemical and histological analyses and motor performance tests. In the chronic model, VEGF stopped the progression of the paralysis and protected motor neurons when administered after AMPA before the onset of the motor symptoms, whereas no protection was observed when administered after the onset. VEGF was also protective in the acute model, but with a short time window, since the protection was effective when administered 1 h but not 2 h after AMPA. Our results indicate that while VEGF has an indubitable neuroprotective effect, its therapeutic potential for halting or delaying the progression of motor neuron loss in ALS would likely have a short effective time frame. PMID:22369757

Tovar-y-Romo, Luis B; Tapia, Ricardo

2012-01-01

351

[Bilateral urolithiasis with zonisamide developed for a short period of time in a 10-year-old girl with intractable epilepsy].  

PubMed

Zonisamide is an antiepileptic drug mainly used in patients with refractory epilepsy. One of the urological adverse effects caused by zonisamide is urinary lithiasis. We reported bilateral urinary lithiasis with zonisamide developed for a short period of time. A 10 year-old girl had been treated with zonisamide for intractable epilepsy for nine years. She progressively developed microscopic hematuria as well as crystalluria while being hospitalized for ventriculoperitoneal shunt infection. A computed tomography (CT) showed bilaterally hydronephrotic kidneys obstructed by multiple ureteral calculi. What was impressive was the fact that any single urinary calculus was not identified in a CT image taken just three weeks prior to this event. Then the diagnosis was made of zonisamide-induced bilateral urinary calculi and zonisamide treatment was discontinued. However, since the deterioration of renal function and left-sided hydronephrosis progressed, we performed the construction of right-sided percutaneous nephrostomy (PNS) and the transurethral placement of a left ureteral stent. Subsequently her condition was stabilized and all of these stones were discharged. The analysis of these stones showed mainly calcium phosphatic calculus. We eventually removed both the right PNS and the left ureteral stent. Since then, there has not been any recurrence thus far. We need to recognize the risk of progressively developing renal calculi during zonisamide treatment for a relatively short period of time in the face of dehydration. PMID:24187857

Sato, Shunsuke; Nishinaka, Kazuyuki; Takahashi, Satoshi; Hirobe, Megumi; Tsukamoto, Taiji

2013-09-01

352

A Response to "Time-Limited Service Alternatives: Using Therapeutic Enactment in Open Group Therapy": A Dramatic Effort to Redefine Short-Term and Time-Limited Services  

ERIC Educational Resources Information Center

Therapeutic Enactment (TE) groups, as presented in the article, "Time-Limited Service Alternatives: Using Therapeutic Enactment in Open Group Therapy," offer an exciting and promising addition to the types of groups traditionally offered in university counseling centers. The brevity of member participation, the lack of empirical evidence of…

Dagley, John C.; Thomas, Chippewa M.

2008-01-01

353

Very short NMR relaxation times of anions in ionic liquids: New pulse sequence to eliminate the acoustic ringing  

NASA Astrophysics Data System (ADS)

NMR relaxation processes of anions were studied in two neat imidazolium-based room temperature ionic liquids (RTILs) 1-decyl-3-methyl-imidazolium bromide- and chloride. The spin-lattice and spin-spin relaxations of 81Br and 35Cl nuclei were found to be extremely fast due to very strong quadrupolar interactions. The determined relaxation rates are comparable with those observed in the solids or in some critical organic solute/water/salt systems. In order to eliminate the acoustic ringing of the probe-head during relaxation times measurements the novel pulse sequence has been devised. It is based on the conventional inversion recovery pulse sequence, however, instead of the last 90° pulse the subsequence of three 90° pulses applied along axes to fulfill the phase cycling condition is used. Using this pulse sequence it was possible to measure T1 for both studied nuclei. The viscosity measurements have been carried out and the rotational correlation times were calculated. The effective 35Cl quadrupolar coupling constant was found to be almost one order lower than that for 81Br, i.e. 1.8 MHz and 16.0 MHz, respectively. Taking into account the facts that the ratio of (Q(35Cl)/Q(81Br))2 ? 0.1 and EFG tensors on the anions are quite similar, analogous structural organizations are expected for both RTILs. The observed T1/T2 (1.27-1.44) ratios were found to be not sufficiently high to confirm the presence of long-living (on the time scale of ?10-8 s) mesoscopic structures or heterogeneities in the studied neat ionic liquids.

Klimavicius, Vytautas; Gdaniec, Zofia; Balevicius, Vytautas

2014-11-01

354

Very short NMR relaxation times of anions in ionic liquids: new pulse sequence to eliminate the acoustic ringing.  

PubMed

NMR relaxation processes of anions were studied in two neat imidazolium-based room temperature ionic liquids (RTILs) 1-decyl-3-methyl-imidazolium bromide- and chloride. The spin-lattice and spin-spin relaxations of 81Br and 35Cl nuclei were found to be extremely fast due to very strong quadrupolar interactions. The determined relaxation rates are comparable with those observed in the solids or in some critical organic solute/water/salt systems. In order to eliminate the acoustic ringing of the probe-head during relaxation times measurements the novel pulse sequence has been devised. It is based on the conventional inversion recovery pulse sequence, however, instead of the last 90° pulse the subsequence of three 90° pulses applied along axes to fulfill the phase cycling condition is used. Using this pulse sequence it was possible to measure T1 for both studied nuclei. The viscosity measurements have been carried out and the rotational correlation times were calculated. The effective 35Cl quadrupolar coupling constant was found to be almost one order lower than that for 81Br, i.e. 1.8 MHz and 16.0 MHz, respectively. Taking into account the facts that the ratio of (Q(35Cl)/Q(81Br))2?0.1 and EFG tensors on the anions are quite similar, analogous structural organizations are expected for both RTILs. The observed T1/T2 (1.27-1.44) ratios were found to be not sufficiently high to confirm the presence of long-living (on the time scale of ?10(-8) s) mesoscopic structures or heterogeneities in the studied neat ionic liquids. PMID:24938418

Klimavicius, Vytautas; Gdaniec, Zofia; Balevicius, Vytautas

2014-11-11

355

Timing of autumn bird migration under climate change: advances in long-distance migrants, delays in short-distance migrants.  

PubMed Central

As a response to increasing spring temperature in temperate regions in recent years, populations of many plant and animal species, including migratory birds, have advanced the seasonal start of their reproduction or growth. However, the effects of climate changes on subsequent events of the annual cycle remain poorly understood. We investigated long-term changes in the timing of autumn migration in birds, a key event in the annual cycle limiting the reproductive period. Using data spanning a 42-year period, we analysed long-term changes in the passage of 65 species of migratory birds through Western Europe. The autumn passage of migrants wintering south of the Sahara has advanced in recent years, presumably as a result of selection pressure to cross the Sahel before its seasonal dry period. In contrast, migrants wintering north of the Sahara have delayed autumn passage. In addition, species with a variable rather than a fixed number of broods per year have delayed passage, possibly because they are free to attempt more broods. Recent climate changes seem to have a simple unidirectional effect on the seasonal onset of reproduction, but complex and opposing effects on the timing of subsequent events in the annual cycle, depending on the ecology and life history of a species. This complicates predictions of overall effects of global warming on avian communities. PMID:12965011

Jenni, Lukas; Kéry, Marc

2003-01-01

356

Measuring inorganic nitrate species with short time resolution from an aircraft platform by dual-channel ozone chemiluminescence  

NASA Astrophysics Data System (ADS)

A measurement technique for determining nitrate (the sum of nitric acid and particulate nitrate) with a few seconds time resolution in plumes is needed to resolve within-plume features. A technique using dual ozone-chemiluminescent NO detectors with a selective nitrate scrubber in one sampling train is promising if used with an appropriate sampling inlet, and if nitrate is the desired analyte. We report the design of, and preliminary results from a dual channel ozone-chemiluminescent system, each channel containing a gold-CO catalyzed converter which reduces all odd nitrogen species (NOy) quantitatively to NO; one channel also contains a nylon filter to remove nitrate from the air stream prior to the converter (this signal is termed NOy*). This system was deployed successfully in a Bell 205 helicopter during the 1995 Southern Oxidants Study Nashville Ozone Study. The converters were mounted forward near the air intake, and zero air and calibration gases admitted simultaneously to both channels during flight operations. The difference signal between the two channels (NOy-NOy*) indicated apparent nitrate levels in the sampled air with a time resolution of <5 s and a limit of detection of about 1 ppbv. Nitrate levels observed with this system in plumes and background air during the Nashville Ozone Study were highly correlated with ozone and varied from below detection limits to ?20 ppbv. Nitrate levels were also highly correlated with the calculated difference between NOy and the sum of NO and NO2 (NOz). Higher nitrate levels as a fraction of NOz were found in power plant plumes (?60%) compared with urban plumes (?50%) and background air, consistent with apparently lower ozone production efficiencies in power plant plumes vis-à-vis urban plumes.

Tanner, Roger L.; Valente, Ralph J.; Meagher, James F.

1998-09-01

357

Lovelock's theorem revisited  

E-print Network

Let (X, g) be an arbitrary pseudo-riemannian manifold. A celebrated result by Lovelock gives an explicit description of all second-order natural (0,2)-tensors on X, that satisfy the conditions of being symmetric and divergence-free. Apart from the dual metric, the Einstein tensor of g is the simplest example. In this paper, we give a short and self-contained proof of this theorem, simplifying the existing one by formalizing the notion of derivative of a natural tensor.

Alberto Navarro; Jose Navarro

2010-12-20

358

Short communication: Added value of rumination time for the prediction of dry matter intake in lactating dairy cows.  

PubMed

The objective of the current study was to quantify the change in the prediction of dry matter intake (DMI) resulting from the inclusion of rumination time (RT) in the 2001 National Research Council (NRC) DMI prediction model. Forty-one Holstein cows fed the same total mixed ration were involved in a 10-wk study. Individual DMI were measured daily. The accuracy and precision of the original NRC prediction model, based on body weight, fat-corrected milk, and week of lactation as independent variables, was compared with the accuracy and precision of the same model with RT as an additional independent variable. The RT estimate was significant in the model developed but had a low value (0.031 kg/h). Root mean square prediction errors were very similar in the 2 models (1.70 and 1.68 kg/d) as were the other indicators (R(2), linear bias, random error, and concordance correlation coefficient) selected to compare the models in this study. These results indicate no gain in DMI prediction precision or accuracy when RT is included in the NRC model. PMID:25129493

Clément, P; Guatteo, R; Delaby, L; Rouillé, B; Chanvallon, A; Philipot, J M; Bareille, N

2014-10-01

359

On violations of Le Chatelier's principle for a temperature change in small systems observed for short times  

NASA Astrophysics Data System (ADS)

Le Chatelier's principle states that when a system is disturbed, it will shift its equilibrium to counteract the disturbance. However for a chemical reaction in a small, confined system, the probability of observing it proceed in the opposite direction to that predicted by Le Chatelier's principle, can be significant. This work gives a molecular level proof of Le Chatelier's principle for the case of a temperature change. Moreover, a new, exact mathematical expression is derived that is valid for arbitrary system sizes and gives the relative probability that a single experiment will proceed in the endothermic or exothermic direction, in terms of a microscopic phase function. We show that the average of the time integral of this function is the maximum possible value of the purely irreversible entropy production for the thermal relaxation process. Our result is tested against computer simulations of the unfolding of a polypeptide. We prove that any equilibrium reaction mixture on average responds to a temperature increase by shifting its point of equilibrium in the endothermic direction.

Dasmeh, Pouria; Searles, Debra J.; Ajloo, Davood; Evans, Denis J.; Williams, Stephen R.

2009-12-01

360

On violations of Le Chatelier's principle for a temperature change in small systems observed for short times.  

PubMed

Le Chatelier's principle states that when a system is disturbed, it will shift its equilibrium to counteract the disturbance. However for a chemical reaction in a small, confined system, the probability of observing it proceed in the opposite direction to that predicted by Le Chatelier's principle, can be significant. This work gives a molecular level proof of Le Chatelier's principle for the case of a temperature change. Moreover, a new, exact mathematical expression is derived that is valid for arbitrary system sizes and gives the relative probability that a single experiment will proceed in the endothermic or exothermic direction, in terms of a microscopic phase function. We show that the average of the time integral of this function is the maximum possible value of the purely irreversible entropy production for the thermal relaxation process. Our result is tested against computer simulations of the unfolding of a polypeptide. We prove that any equilibrium reaction mixture on average responds to a temperature increase by shifting its point of equilibrium in the endothermic direction. PMID:19968347

Dasmeh, Pouria; Searles, Debra J; Ajloo, Davood; Evans, Denis J; Williams, Stephen R

2009-12-01

361

Cardiac-respiratory self-gated cine ultra-short echo time (UTE) cardiovascular magnetic resonance for assessment of functional cardiac parameters at high magnetic fields  

PubMed Central

Background To overcome flow and electrocardiogram-trigger artifacts in cardiovascular magnetic resonance (CMR), we have implemented a cardiac and respiratory self-gated cine ultra-short echo time (UTE) sequence. We have assessed its performance in healthy mice by comparing the results with those obtained with a self-gated cine fast low angle shot (FLASH) sequence and with echocardiography. Methods 2D self-gated cine UTE (TE/TR?=?314 ?s/6.2 ms, resolution: 129?×?129 ?m, scan time per slice: 5 min 5 sec) and self-gated cine FLASH (TE/TR?=?3 ms/6.2 ms, resolution: 129?×?129 ?m, scan time per slice: 4 min 49 sec) images were acquired at 9.4 T. Volume of the left and right ventricular (LV, RV) myocardium as well as the end-diastolic and -systolic volume was segmented manually in MR images and myocardial mass, stroke volume (SV), ejection fraction (EF) and cardiac output (CO) were determined. Statistical differences were analyzed by using Student t test and Bland-Altman analyses. Results Self-gated cine UTE provided high quality images with high contrast-to-noise ratio (CNR) also for the RV myocardium (CNRblood-myocardium?=?25.5?±?7.8). Compared to cine FLASH, susceptibility, motion, and flow artifacts were considerably reduced due to the short TE of 314 ?s. The aortic valve was clearly discernible over the entire cardiac cycle. Myocardial mass, SV, EF and CO determined by self-gated UTE were identical to the values measured with self-gated FLASH and showed good agreement to the results obtained by echocardiography. Conclusions Self-gated UTE allows for robust measurement of cardiac parameters of diagnostic interest. Image quality is superior to self-gated FLASH, rendering the method a powerful alternative for the assessment of cardiac function at high magnetic fields. PMID:23826850

2013-01-01

362

Effects of high pressure homogenisation of raw bovine milk on alkaline phosphatase and microbial inactivation. A comparison with continuous short-time thermal treatments.  

PubMed

Raw whole milk of high microbial quality (58 degrees C), but markedly decreased above 200 MPa when Tin=24 degrees C (T2>60 degrees C). In contrast to inactivation induced by continuous short-time thermal treatments, ALP inactivation induced by HP homogenisation was clearly due to mechanical forces (shear, cavitation and/or impact) in the HP valve and not to the short (<1 s) residence time at temperature T2 in the same valve. Inactivation of the three exogenous microorganisms led to similar conclusions. Homogenisation at 250 MPa or 300 MPa (Tin=24 degrees C) induced a 2-3 log cycle reduction of the total endogenous milk flora and a 1.5-1.8 log cycle reduction of inoculated List. innocua. Higher reduction ratios (2-4 log cycles) were obtained for the two other microorganisms. The highest levels of ALP inactivation corresponded to the highest extents of microbial reduction. Running the milk twice or three times through the homogeniser (recycling), keeping temperature T1 approximately 29 degrees C and pressure=200 MPa, increased homogenisation efficiency. PMID:16834813

Picart, Laëtitia; Thiebaud, Maryse; René, Malika; Pierre Guiraud, Joseph; Cheftel, Jean Claude; Dumay, Eliane

2006-11-01

363

Usefulness of ultrasonic strain measurement-based mechanical properties imaging technique: toward realization of short time diagnosis/treatment  

NASA Astrophysics Data System (ADS)

For various soft tissues (e.g., liver, breast, etc.), we are developing the ultrasonic strain measurement-based mechanical properties (shear modulus, visco-shear modulus, etc.) reconstruction/imaging technique. To clarify the limitation of our quantitative reconstruction/imaging technique as a diagnostic tool for differentiating malignancies, together with improving the spatial resolution and the dynamic range we are collecting the clinical reconstruction image data. Furthermore, we are applying our technique as a monitoring technique for the effectiveness of chemical therapy (e.g., anticancer drug, ethanol, etc.), thermal therapy (e.g., micro, and rf electromagnetic wave, HIFU, LASER, etc.), and cryotherapy. As soft tissues are deformed in 3-D space due to externally situated quasi-static and/or low frequency mechanical sources, multidimensional signal processing improves strain measurement accuracy and reduces inhomogeneity-dependent modulus reconstruction artifacts. These have been verified by us through simulations and phantom/animal in vitro experiments. Briefly, here we discuss the limitations of low dimensional signal processing. Moreover, we exhibit the superiority both on differential diagnosis for these human in vivo malignancies and monitoring for these therapies of our quasi-real time imaging (using conventional US equipment) to conventional B-mode imaging. Our technique is available as a clinical visualization technique both for diagnosis and treatment, and monitored mechanical properties data can also be effectively utilized as the measure for controlling the therapy, i.e., the exposure energy, the foci, the exposure interval, etc. In the near future, suitable combination of various simple and low-invasive therapy techniques with our imaging technique will open up a new clinical style allowing diagnosis and the subsequently immediate treatment. This must substantially reduce the total medical expenses.

Sumi, Chikayoshi; Kubota, Mitsuhiro; Wakabayashi, Gou; Tanabe, Minoru

2003-06-01

364

Generation of attenuation map for MR-based attenuation correction of PET data in the head area employing 3D short echo time MR imaging  

NASA Astrophysics Data System (ADS)

Attenuation correction is a crucial step to get accurate quantification of Positron Emission Tomography (PET) data. An attenuation map to provide attenuation coefficients at 511 keV can be generated using Magnetic Resonance Images (MRI). One of the main steps involved in MR-based attenuation correction (MRAC) of PET data is to separate bone from air. Low signal intensity of bone in conventional MRI makes it difficult to separate bone from air in the head area, while their attenuation coefficients are very different. In literature, several groups proposed ultrashort echo-time (UTE) sequences to differentiate bone from air [4,5,7], because these sequences are capable of imaging tissues with short T2* relaxation time, such as cortical bone; however, they are difficult to use, expensive and time-consuming. Employing short echo-time (STE) MRI in combination with long echo-time (LTE) MRI, and along with high performance image processing algorithms is a good substitute for UTE-based PET attenuation correction; they are widely available, easy to use, inexpensive and much faster than UTE pulse sequences. In this work, we propose the use of STE sequences along with LTE ones, as well as a dedicated image processing method to differentiate bone from air cavities in the head area by creating contrast between the tissues. Attenuation coefficients at 511 kev, relying on literature [5], will then be assigned to the voxels. Acquisition was performed on a clinical 3T Tim Trio scanner (Siemens Medical Solution, Erlangen, Germany), employing a dual echo sequence. To achieve an optimized protocol with the best result for discrimination of bone and air, two types of acquisitions were performed, with and without fat suppression; the acquisition parameters were as follows: TE=1.21/5 ms, TR=5/17, FA=30, and TE=1.12/3.16 ms, TR=5/5, FA=12 for non-fat-suppressed and fat-suppressed protocol, respectively. Contrast enhancement and tissue segmentation were applied as processing steps, to successfully classify voxels into bone, air and soft tissue classes, yielding accuracy, sensitivity and specificity of 88%, 77% and 94%, for non-fat suppressed acquisition, respectively. This method could potentially be as an efficient method for generation of attenuation map in 511 keV for MR-based attenuation correction of PET data in clinical PET/MR applications with mixed air and bone signals.

Khateri, Parisa; Salighe Rad, Hamidreza; Fathi, Anahita; Ay, Mohammad Reza

2013-02-01

365

Regional metabolite concentrations in the brain of healthy dogs measured by use of short echo time, single voxel proton magnetic resonance spectroscopy at 3.0 Tesla.  

PubMed

OBJECTIVE To investigate regional differences of relative metabolite concentrations in the brain of healthy dogs with short echo time, single voxel proton magnetic resonance spectroscopy ((1)H MRS) at 3.0 T. ANIMALS 10 Beagles. PROCEDURES Short echo time, single voxel (1)H MRS was performed at the level of the right and left basal ganglia, right and left thalamus, right and left parietal lobes, occipital lobe, and cerebellum. Data were analyzed with an automated fitting method (linear combination model). Metabolite concentrations relative to water content were obtained, including N-acetyl aspartate, total choline, creatine, myoinositol, the sum of glutamine and glutamate (glutamine-glutamate complex), and glutathione. Metabolite ratios with creatine as the reference metabolite were calculated. Concentration differences between right and left hemispheres and sexes were evaluated with a Wilcoxon signed rank test and among various regions of the brain with an independent t test and 1-way ANOVA. RESULTS No significant differences were detected between sexes and right and left hemispheres. All metabolites, except the glutamine-glutamate complex and glutathione, had regional concentrations that differed significantly. The creatine concentration was highest in the basal ganglia and cerebellum and lowest in the parietal lobes. The N-acetyl aspartate concentration was highest in the parietal lobes and lowest in the cerebellum. Total choline concentration was highest in the basal ganglia and lowest in the occipital lobe. CONCLUSIONS AND CLINICAL RELEVANCE Metabolite concentrations differed among brain parenchymal regions in healthy dogs. This study may provide reference values for clinical and research studies involving (1)H MRS performed at 3.0 T. PMID:25629910

Carrera, Inés; Richter, Henning; Meier, Dieter; Kircher, Patrick R; Dennler, Matthias

2015-02-01

366

The Long and the Short of it: On the Nature and Origin of Functional Overlap Between Representations of Space and Time  

PubMed Central

When we describe time, we often use the language of space (The movie was long; The deadline is approaching). Experiments 1–3 asked whether—as patterns in language suggest—a structural similarity between representations of spatial length and temporal duration is easier to access than one between length and other dimensions of experience, such as loudness. Adult participants were shown pairings of lines of different length with tones of different duration (Experiment 1) or tones of different loudness (Experiment 2). The length of the lines and duration or loudness of the tones was either positively or negatively correlated. Participants were better able to bind particular lengths and durations when they were positively correlated than when they were not, a pattern not observed for pairings of lengths and tone amplitudes, even after controlling for the presence of visual cues to duration in Experiment 1 (Experiment 3). This suggests that representations of length and duration may functionally overlap to a greater extent than representations of length and loudness. Experiments 4 and 5 asked whether experience with and mastery of words like long and short—which can flexibly refer to both space and time—itself creates this privileged relationship. Nine-month-old infants, like adults, were better able to bind representations of particular lengths and durations when these were positively correlated (Experiment 4), and failed to show this pattern for pairings of lengths and tone amplitudes (Experiment 5). We conclude that the functional overlap between representations of length and duration does not result from a metaphoric construction processes mediated by learning to flexibly use words such as long and short. We suggest instead that it may reflect an evolutionary recycling of spatial representations for more general purposes. PMID:20537324

Srinivasan, Mahesh; Carey, Susan

2010-01-01

367

Lithium in the Pleiades Revisited  

NASA Astrophysics Data System (ADS)

New Li abundances have been derived for some 15-20 Pleiades dwarfs using new high-resolution and high S/N spectroscopy from HET/HRS. Previous studies suggested that our objects, all modest (projected) rotators, evinced considerable scatter in their Li abundances. We revisit the question of this scatter and its origin. This work has been supported by NSF grants AST 00-86576 and 02-39518, a South Carolina Space Grant Scholarship award, a generous donation from the Curry Foundation of Seneca, SC, and the NOAO Public Access Program.

King, J. R.; Hobbs, L. M.; Schuler, S. C.; Pinsonneault, M. H.

2003-12-01

368

Series RC circuits revisited  

Microsoft Academic Search

The measured and predicted properties of a series RC circuit containing a battery, a constant resistance R, and a time-dependent capacitance C are reported and compared with those of a conventional RC circuit with constant R and C and a time-dependent input voltage. The apparatus needed for these experiments is available in most undergraduate physics departments and the experiments are

J. E. Gordon; P. R. Grant

2004-01-01

369

Surface properties of nitrided layer on AISI 316L austenitic stainless steel produced by high temperature plasma nitriding in short time  

NASA Astrophysics Data System (ADS)

It has generally been believed that the formation of the S phase or expanded austenite ?N with enough thickness depends on the temperature (lower than 480 °C) and duration of the process. In this work, we attempt to produce nitrogen expanded austenite layer at high temperature in short time. Nitriding of AISI 316L austenitic stainless steel was carried out at high temperatures (>520 °C) for times ranging from 5 to 120 min. The microstructures, chemical composition, the thickness and the morphology of the nitrided layer, as well as its surface hardness, were investigated using X-ray diffraction, X-ray photoelectron spectroscopy, optical microscopy, scanning electron microscopy, and microhardness tester. The corrosion properties of the untreated and nitrided samples were evaluated using anodic polarization tests in 3.5% NaCl solution. The results confirmed that nitrided layer was shown to consist of ?N and a small amount of free-CrN and iron nitrides. High temperature plasma nitriding not only increased the surface hardness but also improved the corrosion resistance of the austenitic stainless steel, and it can critically reduce processing time compared with low temperature nitriding.

Li, Yang; Wang, Zhuo; Wang, Liang

2014-04-01

370

Retention of a 24-hour time memory in Syrian hamsters carrying the 20-hour short circadian period mutation in casein kinase-1? (ck1?tau/tau).  

PubMed

Circadian rhythmic expression of conditioned place avoidance (CPA) was produced in Syrian hamsters homozygous for the circadian short period mutation, tau. In constant dim red light neither the 20 h endogenous period, nor a 20 h place conditioning schedule eliminated the 24 h modulation of CPA behavior described previously for wild type (wt) hamsters and other species. Tau mutants exhibited a 20 h rhythm superimposed on the 24 h modulation. The 20 h component was removed selectively with lesions of the suprachiasmatic nucleus. Wt animals conditioned on a 20 h schedule did not produce a 20 h rhythm, but still expressed the 24 h modulation. The results show that the context entrainable oscillator (CEO) underlying memory for the timing of an unconditioned stimulus, retains a period of about 24 h regardless of clock gene background (tau mutation) and/or the conditioning schedule (24 vs 20 h). Therefore the CEO responsible for time memory is distinct from the biological clock controlling activity; the underlying circadian molecular mechanisms may differ from the ubiquitous transcription-translation feedback oscillator; and time memory itself is not classically conditioned. PMID:24933476

Cain, Sean W; Yoon, Jeena; Shrestha, Tenjin C; Ralph, Martin R

2014-10-01

371

Feature extraction and recognition for rolling element bearing fault utilizing short-time Fourier transform and non-negative matrix factorization  

NASA Astrophysics Data System (ADS)

Due to the non-stationary characteristics of vibration signals acquired from rolling element bearing fault, the time-frequency analysis is often applied to describe the local information of these unstable signals smartly. However, it is difficult to classify the high dimensional feature matrix directly because of too large dimensions for many classifiers. This paper combines the concepts of time-frequency distribution(TFD) with non-negative matrix factorization(NMF), and proposes a novel TFD matrix factorization method to enhance representation and identification of bearing fault. Throughout this method, the TFD of a vibration signal is firstly accomplished to describe the localized faults with short-time Fourier transform(STFT). Then, the supervised NMF mapping is adopted to extract the fault features from TFD. Meanwhile, the fault samples can be clustered and recognized automatically by using the clustering property of NMF. The proposed method takes advantages of the NMF in the parts-based representation and the adaptive clustering. The localized fault features of interest can be extracted as well. To evaluate the performance of the proposed method, the 9 kinds of the bearing fault on a test bench is performed. The proposed method can effectively identify the fault severity and different fault types. Moreover, in comparison with the artificial neural network(ANN), NMF yields 99.3% mean accuracy which is much superior to ANN. This research presents a simple and practical resolution for the fault diagnosis problem of rolling element bearing in high dimensional feature space.

Gao, Huizhong; Liang, Lin; Chen, Xiaoguang; Xu, Guanghua

2014-12-01

372

Increasing strength, ductility and impact toughness of ultrafine-grained 6063 aluminium alloy by combining ECAP and a high-temperature short-time aging  

NASA Astrophysics Data System (ADS)

Since fully-dense ultrafine or nanocrystalline bulk materials can be processed, there has been an increasing scientific interest in several plastic deformation (SPD) procedures, particularly in the last decade. Especially the equal-channel angular pressing (ECAP) has widely been investigated due to its ability of producing billets sufficiently large for industrial applications in functional or structural components. The significant strength increase based on grain refinement is typically accompanied by a significant decrease in ductility and toughness. Within this work, a new methodology was applied for combining ECAP with a subsequent high-temperature short-time aging for the 6063 aluminium alloy. An increase in strength, ductility as well as impact toughness regarding its coarse grained counterparts was reached. More precisely, ultimate tensile strength, elongation to failure and impact toughness were increased by 46%, 21% and 40% respectively. This was observed after only one run of ECAP at room temperature in a solid-solution treated condition and an aging at 170° C for 18 minutes. The regular aging time for maximum strength at 170° C is around 6 hours. Longer exposure times lead to recrystallisation and, as for regular aging, it leads to overaging, both causing a decrease of properties. The work demonstrates a strategy for an efficient processing of commercial Al-Mg-Si alloys with outstanding mechanical properties.

Meyer, L. W.; Schönherr, R.; Hockauf, M.

2010-07-01

373

EPR before EPR: A 1930 Einstein-Bohr thought Experiment Revisited  

ERIC Educational Resources Information Center

In 1930, Einstein argued against the consistency of the time-energy uncertainty relation by discussing a thought experiment involving a measurement of the mass of the box which emitted a photon. Bohr seemingly prevailed over Einstein by arguing that Einstein's own general theory of relativity saves the consistency of quantum mechanics. We revisit…

Nikolic, Hrvoje

2012-01-01

374

THE BOY WHO CRIED WOLF REVISITED: THE IMPACT OF FALSE ALARM INTOLERANCE ON  

E-print Network

THE BOY WHO CRIED WOLF REVISITED: THE IMPACT OF FALSE ALARM INTOLERANCE ON COST-LOSS SCENARIOS M's fable about the "The Boy who Cried Wolf", a young shepherd boy guarding the village flock cries. This event is repeated two or three times before a wolf actually does show up on the hillside. The boy cries

Stevenson, Paul

375

54 IEEE MICROWAVE AND GUIDED WAVE LETTERS, VOL. 9, NO. 2, FEBRUARY 1999 FDTD Dispersion Revisited  

E-print Network

54 IEEE MICROWAVE AND GUIDED WAVE LETTERS, VOL. 9, NO. 2, FEBRUARY 1999 FDTD Dispersion Revisited: Faster-Than-Light Propagation John B. Schneider, Member, IEEE, and Christopher L. Wagner Abstract--The numerical dispersion relation that governs the propagation of fields in a finite-difference time

Schneider, John B.

376

Foraging destinations and marine habitat use of short-tailed albatrosses: A multi-scale approach using first-passage time analysis  

USGS Publications Warehouse

We used satellite telemetry, remotely sensed data (bathymetry, chlorophyll a (chl a), sea-surface temperature (SST), wind speed) and first-passage time (FPT) analysis to determine the distribution, movement patterns, and habitat associations of short-tailed albatrosses (Phoebastria albatrus) during the non-breeding season, 2002 and 2003. Satellite transmitters were deployed on birds immediately prior to their departure from a breeding colony at Torishima, Japan (n = 11), or at-sea in the Aleutian Islands (n = 3). Tracking durations ranged from 51 to 138 days for a total of 6709 locations after filtering (131 - 808 per bird). FPT (time required to transit a circle of given radius) revealed the location and spatial scale of area-restricted search (ARS) patterns along flight paths. On average, ARS occurred within 70 km radii. Consequently, the fit of the habitat use models increased at spatial scales beyond a 40 km FPT radius (R2 = 0.31) and stabilized for scales of 70 km and larger (R2=0.40- 0.51). At all scales, wind speed, depth or depth gradient, and chl a or chl a gradient had a significant effect on FPT (i.e., residence time). FPT increased within regions of higher gradients of depth and chl a. In contrast, FPT decreased within regions of greater depth and wind speed, with a significant interaction of wind speed and depth at some scales. Sea-surface temperature or its interactions were only significant at large spatial scales (???160 km FPT radius). Albatrosses engaged in ARS activities primarily over the shelf break and slope, including Kuroshio and Oyashio regions off the western subarctic gyre. Occasionally, birds transited the northern boundary of the Kuroshio Extension while in-route to the Aleutian Islands and Bering Sea, but overall spent little time in the western gyre. In the Aleutian Islands, ARS occurred within straits, particularly along the central and western part of the archipelago. In the Bering Sea, ARS occurred along the northern continental shelf break, the Kamchatka Current region, and east of the Commander Islands. Non-breeding short-tailed albatross concentrate foraging in oceanic areas characterized by gradients in topography and water column productivity. This study provides an understanding of the foraging ecology for a highly migratory, imperiled seabird, and confirms the importance of shelf break and slope regions as hot spots for a variety of top marine predators in the North Pacific.

Suryan, R.M.; Sato, F.; Balogh, G.R.; David, Hyrenbach K.; Sievert, P.R.; Ozaki, K.

2006-01-01

377

Foraging destinations and marine habitat use of short-tailed albatrosses: A multi-scale approach using first-passage time analysis  

NASA Astrophysics Data System (ADS)

We used satellite telemetry, remotely sensed data (bathymetry, chlorophyll a (chl a), sea-surface temperature (SST), wind speed) and first-passage time (FPT) analysis to determine the distribution, movement patterns, and habitat associations of short-tailed albatrosses ( Phoebastria albatrus) during the non-breeding season, 2002 and 2003. Satellite transmitters were deployed on birds immediately prior to their departure from a breeding colony at Torishima, Japan ( n=11), or at-sea in the Aleutian Islands ( n=3). Tracking durations ranged from 51 to 138 days for a total of 6709 locations after filtering (131 - 808 per bird). FPT (time required to transit a circle of given radius) revealed the location and spatial scale of area-restricted search (ARS) patterns along flight paths. On average, ARS occurred within 70 km radii. Consequently, the fit of the habitat use models increased at spatial scales beyond a 40 km FPT radius ( R2=0.31) and stabilized for scales of 70 km and larger ( R2=0.40- 0.51). At all scales, wind speed, depth or depth gradient, and chl a or chl a gradient had a significant effect on FPT (i.e., residence time). FPT increased within regions of higher gradients of depth and chl a. In contrast, FPT decreased within regions of greater depth and wind speed, with a significant interaction of wind speed and depth at some scales. Sea-surface temperature or its interactions were only significant at large spatial scales (?160 km FPT radius). Albatrosses engaged in ARS activities primarily over the shelf break and slope, including Kuroshio and Oyashio regions off the western subarctic gyre. Occasionally, birds transited the northern boundary of the Kuroshio Extension while in-route to the Aleutian Islands and Bering Sea, but overall spent little time in the western gyre. In the Aleutian Islands, ARS occurred within straits, particularly along the central and western part of the archipelago. In the Bering Sea, ARS occurred along the northern continental shelf break, the Kamchatka Current region, and east of the Commander Islands. Non-breeding short-tailed albatross concentrate foraging in oceanic areas characterized by gradients in topography and water column productivity. This study provides an understanding of the foraging ecology for a highly migratory, imperiled seabird, and confirms the importance of shelf break and slope regions as hot spots for a variety of top marine predators in the North Pacific.

Suryan, Robert M.; Sato, Fumio; Balogh, Gregory R.; David Hyrenbach, K.; Sievert, Paul R.; Ozaki, Kiyoaki

2006-02-01

378

Smith Theory Revisited William G. Dwyer  

E-print Network

Smith Theory Revisited William G. Dwyer Clarence W. Wilkerson* 1 Introduction In the late 1930's, P. A. Smith began the investigation. This thread has continued now for almost fifty years. Smith was successful in calculating the cohomology

Wilkerson, Clarence

379

The Reunion Fund Revisited.  

ERIC Educational Resources Information Center

Minicapital campaigns at the 25th and 50th reunions at Williams College are described. Leadership, organization, timing, budget, purpose, marketing, and a solid foundation of positive alumni attitudes toward supporting the college help to make a successful campaign. (MLW)

Carpenter, Russell F.

1982-01-01

380

Short stature  

MedlinePLUS

... while in the womb ( intrauterine growth restriction ) or small for gestational age This list does not include every possible cause ... by 2 - 3 inches. The child was born small for gestational age If your child is a boy with short ...

381

Critical boundary sine-Gordon revisited  

SciTech Connect

We revisit the exact solution of the two space-time dimensional quantum field theory of a free massless boson with a periodic boundary interaction and self-dual period. We analyze the model by using a mapping to free fermions with a boundary mass term originally suggested in Ref. [J. Polchinski, L. Thorlacius, Phys. Rev. D 50 (1994) 622]. We find that the entire SL (2, C) family of boundary states of a single boson are boundary sine-Gordon states and we derive a simple explicit expression for the boundary state in fermion variables and as a function of sine-Gordon coupling constants. We use this expression to compute the partition function. We observe that the solution of the model has a strong-weak coupling generalization of T-duality. We then examine a class of recently discovered conformal boundary states for compact bosons with radii which are rational numbers times the self-dual radius. These have simple expression in fermion variables. We postulate sine-Gordon-like field theories with discrete gauge symmetries for which they are the appropriate boundary states.

Hasselfield, M. [Pacific Institute for Theoretical Physics, Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada); Lee, Taejin [Pacific Institute for Theoretical Physics, Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada); Department of Physics, Kangwon University, Chuncheon 200-701 (Korea, Republic of); Asia Pacific Center for Theoretical Physics, Pohang 790-784 (Korea, Republic of); Semenoff, G.W. [Pacific Institute for Theoretical Physics, Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada) and Institute des Hautes Etudes Scientifiques, Le Bois-Marie 35, F-91440 Bures-sur-Yvette (France)]. E-mail: gordonws@phas.ubc.ca; Stamp, P.C.E. [Pacific Institute for Theoretical Physics, Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada)

2006-12-15

382

Monitoring of hematopoietic chimerism after transplantation for pediatric myelodysplastic syndrome: real-time or conventional short tandem repeat PCR in peripheral blood or bone marrow?  

PubMed

Quantitative real-time PCR (qPCR) has been proposed as a highly sensitive method for monitoring hematopoietic chimerism and may serve as a surrogate marker for the detection of minimal residual disease minimal residual disease in myelodysplastic syndrome (MDS), until specific methods of detection become available. Because a systematic comparison of the clinical utility of qPCR with the gold standard short tandem repeat (STR)-PCR has not been reported, we retrospectively measured chimerism by qPCR in 54 children transplanted for MDS in a previous study. Results obtained by STR-PCR in the initial study served as comparison. Because the detection limit of qPCR was sufficiently low to detect an autologous background, we defined the sample as mixed chimera if the proportion of recipient-derived cells exceeded .5%. The true positive rates were 100% versus 80% (qPCR versus STR-PCR, not significant), and mixed chimerism in most cases was detected earlier by qPCR than by STR-PCR (median, 31 days) when chimerism was quantified concurrently in peripheral blood and bone marrow. Both methods revealed a substantial rate of false positives (22.7% versus 13.6%, not significant), indicating the importance of serial testing of chimerism to monitor its progression. Finally, we propose criteria for monitoring chimerism in pediatric MDS with regard to the subtypes, specimens, PCR method, and timing of sampling. PMID:25087899

Willasch, Andre M; Kreyenberg, Hermann; Shayegi, Nona; Rettinger, Eva; Meyer, Vida; Zabel, Marion; Lang, Peter; Kremens, Bernhard; Meisel, Roland; Strahm, Brigitte; Rossig, Claudia; Gruhn, Bernd; Klingebiel, Thomas; Niemeyer, Charlotte M; Bader, Peter

2014-12-01

383

Climate-induced variations in lake levels: A mechanism for short-term sea level change during non-glacial times  

SciTech Connect

Variations in insolation due to periodic orbital parameters can cause climatic changes and associated variations in the intensity of monsoonal circulation. This can lead to significant variations in the levels of internally draining lakes on timescales of 10,000 to 100,000 years in regions affected by the monsoon (20,000 years for orbital precession). These variations may be responsible for small scale (few meters) eustatic sea level changes in an ice-free Earth, and may contribute to sea level changes in the presence of ice as well. The authors have estimated the volume of empty present lake basins in the regions of Asia and North Africa influenced by the monsoon. The surface water volume alone of these basins is equivalent to a two meter difference in sea level, but is considerably augmented by groundwater associated with an increase in lake level. The lake variation mechanism for sea level change has its basis in the Quaternary record of climate change and associated explanatory models. However, the argument also applies to earlier, non-glacial periods of geologic time. Clear evidence for the presence of ice in the Triassic is lacking. However, there is evidence for short-term periodic fluctuations of lake levels as well as sea level during that time. These sea level changes, as well as those in the Devonian, Jurassic, and Cretaceous, may be driven by periodic fluctuation in lacustrine and groundwater storage resulting from orbitally forced changes in monsoon intensity, even in the absence of significant glacial ice.

Jacobs, D. (American Museum of Natural History, N.Y. (United States)); Sahagian, D. (Ohio State Univ., Columbus, OH (United States). Dept of Geological Sciences)

1992-01-01

384

Fermat's Principle Revisited.  

ERIC Educational Resources Information Center

A principle is presented to show that, if the time of passage of light is expressible as a function of discrete variables, one may dispense with the more general method of the calculus of variations. The calculus of variations and the alternative are described. The phenomenon of mirage is discussed. (Author/KR)

Kamat, R. V.

1991-01-01

385

Green Science: Revisiting Recycling  

ERIC Educational Resources Information Center

Recycling has been around for a long time--people have reused materials and refashioned them into needed items for thousands of years. More recently, war efforts encouraged conservation and reuse of materials, and in the 1970s recycling got its official start when recycling centers were created. Now, curbside recycling programs and recycling…

Palliser, Janna

2011-01-01

386

Projectile Motion Revisited.  

ERIC Educational Resources Information Center

Analyzes projectile motion using symmetry and simple geometry. Deduces the direction of velocity at any point, range, time of flight, maximum height, safety parabola, and maximum range for a projectile launched upon a plane inclined at any angle with respect to the horizontal. (Author/GA)

Lucie, Pierre

1979-01-01

387

...... Frechet Distance Revisited and Extended Sariel Har-Peled1  

E-print Network

. ...... Fr´echet Distance Revisited and Extended Sariel Har-Peled1 Benjamin Raichel1 1UIUC, Illinois, USA June 15, 2011 Har-Peled and Raichel (UIUC) Fr´echet Distance Revisited and Extended June 15 recognition, etc. Har-Peled and Raichel (UIUC) Fr´echet Distance Revisited and Extended June 15, 2011 2 / 26

Har-Peled, Sariel

388

Improving medication adherence in diabetes type 2 patients through Real Time Medication Monitoring: a Randomised Controlled Trial to evaluate the effect of monitoring patients' medication use combined with short message service (SMS) reminders  

Microsoft Academic Search

BACKGROUND: Innovative approaches are needed to support patients' adherence to drug therapy. The Real Time Medication Monitoring (RTMM) system offers real time monitoring of patients' medication use combined with short message service (SMS) reminders if patients forget to take their medication. This combination of monitoring and tailored reminders provides opportunities to improve adherence. This article describes the design of an

Marcia Vervloet; Liset van Dijk; Jacqueline Santen-Reestman; Bas van Vlijmen; Marcel L Bouvy; Dinny H de Bakker

2011-01-01

389

GLOBAL STAR FORMATION REVISITED  

SciTech Connect

A general treatment of disk star formation is developed from a dissipative multiphase model, with the dominant dissipation due to cloud collisions. The Schmidt-Kennicutt (SK) law emerges naturally for star-forming disks and starbursts. We predict that there should be an inverse correlation between Tully-Fisher law and SK law residuals. The model is extended to include a multiphase treatment of supernova feedback that leads to a turbulent pressure-regulated generalization of the star formation law and is applicable to gas-rich starbursts. Enhanced pressure, as expected in merger-induced star formation, enhances star formation efficiency. An upper limit is derived for the disk star formation rate in starbursts that depends on the ratio of global ISM to cloud pressures. We extend these considerations to the case where the interstellar gas pressure in the inner galaxy is dominated by outflows from a central active galactic nucleus (AGN). During massive spheroid formation, AGN-driven winds trigger star formation, resulting in enhanced supernova feedback and outflows. The outflows are comparable to the AGN-boosted star formation rate and saturate in the super-Eddington limit. Downsizing of both SMBH and spheroids is a consequence of AGN-driven positive feedback. Bondi accretion feeds the central black hole with a specific accretion rate that is proportional to the black hole mass. AGN-enhanced star formation is mediated by turbulent pressure and relates spheroid star formation rate to black hole accretion rate. The relation between black hole mass and spheroid velocity dispersion has a coefficient (Salpeter time to gas consumption time ratio) that provides an arrow of time. Highly efficient, AGN-boosted star formation can occur at high redshift.

Silk, Joseph [Physics Department, University of Oxford, 1 Keble Road, Oxford OX1 3RH (United Kingdom); Norman, Colin [Physics Department, Johns Hopkins University, 2400 North Charles Street, Baltimore, MD 21218 (United States)], E-mail: silk@astro.ox.ac.uk, E-mail: norman@stsci.edu

2009-07-20

390

Phantom Thermodynamics Revisited  

E-print Network

Although generalized Chaplygin phantom models do not show any big rip singularities, we investigated k-essence models together with noncanonical kinetic energy for which there might be a big rip future singularity in the phantom region. We present our results by finely tuning the parameter ($\\beta$) which is closely related to the canonical kinetic term in $k$-essence formalism. The scale factor $a(t)$ could be negative and decreasing within a specific range of $\\beta$ during the initial evolutional period. There will be no singularity for the scale factor for all times once $\\beta$ is carefully selected.

A. Kwang-Hua Chu

2005-04-18

391

Schrödinger equation revisited  

PubMed Central

The time-dependent Schrödinger equation is a cornerstone of quantum physics and governs all phenomena of the microscopic world. However, despite its importance, its origin is still not widely appreciated and properly understood. We obtain the Schrödinger equation from a mathematical identity by a slight generalization of the formulation of classical statistical mechanics based on the Hamilton–Jacobi equation. This approach brings out most clearly the fact that the linearity of quantum mechanics is intimately connected to the strong coupling between the amplitude and phase of a quantum wave. PMID:23509260

Schleich, Wolfgang P.; Greenberger, Daniel M.; Kobe, Donald H.; Scully, Marlan O.

2013-01-01

392

The super collider revisited  

SciTech Connect

In this paper, the authors suggest a revised version of the Superconducting Super Collider (SSC) that employs the planned SSC first stage machine as an injector of 0.5 TeV protons into a power laser accelerator. The recently developed Non-linear Amplification of Inverse Bremsstrahlung Acceleration (NAIBA) concept dictates the scenario of the next stage of acceleration. Post Star Wars lasers, available at several laboratories, can be used for the purpose. The 40 TeV CM energy, a target of the SSC, can be obtained with a new machine which can be 20 times smaller than the planned SSC.

Hussein, M.S.; Pato, M.P. (Nuclear Theory and Elementary Particle Phenomenology Group, Inst. de Fisica, Univ. de Sao Paulo, C.P. 20516, 01498 Sao Paulo (BR))

1992-05-20

393

Ancient deforestation revisited.  

PubMed

The image of the classical Mediterranean environment of the Greeks and Romans had a formative influence on the art, literature, and historical perception of modern Europe and America. How closely does is this image congruent with the ancient environment as it in reality existed? In particular, how forested was the ancient Mediterranean world, was there deforestation, and if so, what were its effects? The consensus of historians, geographers, and other scholars from the mid-nineteenth century through the first three quarters of the twentieth century was that human activities had depleted the forests to a major extent and caused severe erosion. My research confirmed this general picture. Since then, revisionist historians have questioned these conclusions, maintaining instead that little environmental damage was done to forests and soils in ancient Greco-Roman times. In a reconsideration of the question, this paper looks at recent scientific work providing proxy evidence for the condition of forests at various times in ancient history. I look at three scientific methodologies, namely anthracology, palynology, and computer modeling. Each of these avenues of research offers support for the concept of forest change, both in abundance and species composition, and episodes of deforestation and erosion, and confirms my earlier work. PMID:20669043

Hughes, J Donald

2011-01-01

394

Time-Course Study of Different Innate Immune Mediators Produced by Ultraviolet-Irradiated Skin. Comparative Effects of Short and Daily versus a Single Harmful UV Exposure.  

PubMed

The modulatory effects of solar ultraviolet radiation (UVR) on the immune system have been widely studied. As the skin is the main target of UVR, our purpose was to compare the impact of two contrasting ways to be exposed to sunlight on the skin innate immunity. Hairless mice were UV irradiated with a single high UV dose (shUVd) simulating a harmful exposure, or with repetitive low UV doses (rlUVd) simulating short occasional daily exposures. Skin samples were taken at different times post-UV irradiation to evaluate skin histology, inflammatory cell recruitment, epidermal T cell population and the mitochondrial function of epidermal cells. The transcriptional profiles of pro-inflammatory cytokines, chemokines, antimicrobial peptides and TLRs were evaluated by RT-PCR and ELISA in tissue homogenates. Finally, a lymphangiography was performed to assess modification in the lymphatic vessel system. A shUVd produces a deep inflammatory state characterized by the production of pro-inflammatory cytokines and chemokines that, in turn, induces the recruitment of neutrophils and macrophages into the irradiated area. On the other hand, rlUVd drive the skin to a photo-induced alert state in which there is no sign of inflammation, but the epithelium undergoes changes in thickness, the lymphatic circulation increases, and the transcription of antimicrobial peptides is induced. This article is protected by copyright. All rights reserved. PMID:25438991

Cela, E M; Friedrich, A; Paz, M L; Vanzulli, S I; Leoni, J; González Maglio, D H

2014-11-28

395

Statistical Time-Resolved Spectroscopy: A higher fraction of short-period binaries for metal-rich F-type dwarfs in SDSS  

E-print Network

Stellar multiplicity lies at the heart of many problems in modern astrophysics, including the physics of star formation, the observational properties of unresolved stellar populations, and the rates of interacting binaries such as cataclysmic variables, X-ray binaries, and Type Ia supernovae. However, little is known about the stellar multiplicity of field stars in the Milky Way, in particular about the differences in the multiplicity characteristics between metal-rich disk stars and metal-poor halo stars. In this study we perform a statistical analysis of ~15,000 F-type dwarf stars in the Milky Way through time-resolved spectroscopy with the sub-exposures archived in the Sloan Digital Sky Survey. We obtain absolute radial velocity measurements through template cross-correlation of individual sub-exposures with temporal baselines varying from minutes to years. These sparsely sampled radial velocity curves are analyzed using Markov chain Monte Carlo techniques to constrain the very short-period binary fraction...

Hettinger, T; Strader, J; Bickerton, S J; Beers, T C

2015-01-01

396

Dynamic quantification of intracellular calcium and protein tyrosine phosphorylation in cryopreserved boar spermatozoa during short-time incubation with oviductal fluid.  

PubMed

Freshly ejaculated boar spermatozoa require several hours of exposure to capacitating conditions to undergo capacitation. We hypothesized that cryopreserved boar spermatozoa might elicit a capacitation response after a relatively shorter time of exposure to capacitating conditions. Washed, frozen-thawed boar spermatozoa were incubated separately with pre-ovulatory isthmic oviductal fluid (EODF), post-ovulatory ODF (MODF), capacitation medium (CM), and noncapacitating medium (NCM) for 60 minutes. Aliquots of spermatozoa were taken at 0, 5, 15, 30, and 60 minutes during incubation and sperm kinematics, intracellular calcium [Ca2(+)]i content, and protein tyrosine phosphorylation (PTP) were studied. The proportion of motile spermatozoa increased significantly after 5 minutes of incubation with EODF. A similar increase was not observed in the other groups. During the initial 5 minutes of incubation, the proportion of spermatozoa with high [Ca(2+)]i decreased significantly in all four groups. The proportion of tyrosine phosphorylated spermatozoa increased from 6.49 ± 1.93% to 15.42 ± 3.58% and 18.41 ± 1.57% in EODF and MODF groups, respectively, at 5 minutes of incubation. Neither CM nor NCM elicited any immediate effect on PTP in spermatozoa. There was a positive and significant correlation between [Ca(2+)]i and sperm motility (P = 0.009). It may be concluded that frozen-thawed boar spermatozoa undergo capacitation-associated changes after a relatively short exposure to EODF, and there are some subpopulations of spermatozoa that undergo PTP despite possessing low [Ca(2+)]i. PMID:25175760

Kumaresan, A; González, R; Johannisson, A; Berqvist, A-S

2014-11-01

397

[Revisiting bipolar disorder].  

PubMed

According to the theory of evolution of Charles Darwin which is an author of The Origin of Species, human being evolves after long time to be profitable to "prosperity of a kind", and it is thought that there is the adaptive meaning. In other words, man stand on various creatures in number, and it may be said that human being building a high civilized society is the creature which was able to have an element of chosen mind and body in natural selection. However, a disease does not disappear from our daily life and tends to consider us to be "the misfortune" even if we human being is easy to suffer from a disease. "Evolution medicine" (Darwinian medicine) drop hint of meaning/the significance in aging and the process of the pathology. This paper refers to such a conception of bipolar disorder. PMID:17877000

Senjyu, Yoshika; Ozawa, Hiroki

2007-09-01

398

Polynomial Supertree Methods Revisited  

PubMed Central

Supertree methods allow to reconstruct large phylogenetic trees by combining smaller trees with overlapping leaf sets into one, more comprehensive supertree. The most commonly used supertree method, matrix representation with parsimony (MRP), produces accurate supertrees but is rather slow due to the underlying hard optimization problem. In this paper, we present an extensive simulation study comparing the performance of MRP and the polynomial supertree methods MinCut Supertree, Modified MinCut Supertree, Build-with-distances, PhySIC, PhySIC_IST, and super distance matrix. We consider both quality and resolution of the reconstructed supertrees. Our findings illustrate the tradeoff between accuracy and running time in supertree construction, as well as the pros and cons of voting- and veto-based supertree approaches. Based on our results, we make some general suggestions for supertree methods yet to come. PMID:22229028

Brinkmeyer, Malte; Griebel, Thasso; Böcker, Sebastian

2011-01-01

399

The Shakespearean Principle Revisited  

PubMed Central

Let every eye negotiate for itself and trust no agent. That line is from William Shakespeare's Much Ado About Nothing. 1 To me, it is a fundamental doctrine of patient care, and I have named it the Shakespearean Principle.2 It stimulates skepticism,3 promotes doubt,4 improves communication, fosters proper decision-making, and protects against a malady that currently plagues our profession—herd mentality.5 This editorial shows what can happen when doctors violate the Shakespearean Principle. The story is real and tells of a woman whose doctor unintentionally killed her. To ensure anonymity, the time and place of the tragedy, as well as the players involved, have been changed. PMID:22412219

Fred, Herbert L.

2012-01-01

400

de Sitter supersymmetry revisited  

NASA Astrophysics Data System (ADS)

We present the basic = 1 superconformal field theories in four-dimensional de Sitter space-time, namely the non-abelian super Yang-Mills theory and the chiral multiplet theory with gauge interactions or cubic superpotential. These theories have eight supercharges and are invariant under the full SO(4, 2) group of conformal symmetries, which includes the de Sitter isometry group SO(4, 1) as a subgroup. The theories are ghost-free and the anti-commutator ? ? { Q ? , Q ? †} is positive. SUSY Ward identities uniquely select the Bunch-Davies vacuum state. This vacuum state is invariant under superconformal transformations, despite the fact that de Sitter space has non-zero Hawking temperature. The = 1 theories are classically invariant under the SU(2 , 2|1) superconformal group, but this symmetry is broken by radiative corrections. However, no such difficulty is expected in the = 4 theory, which is presented in appendix B.

Anous, Tarek; Freedman, Daniel Z.; Maloney, Alexander

2014-07-01

401

Revisiting sample entropy analysis  

NASA Astrophysics Data System (ADS)

We modify the definition of sample entropy (SaEn) by incorporating a time delay between the components of the block (from which the densities are estimated) and show that the modified method characterizes the complexity of the system better than the original version. We apply the modified SaEn to the standard deterministic systems and stochastic processes (uncorrelated and long range correlated (LRC) processes) and show that the underlying complexity of the system is better quantified by the modified method. We extend this analysis to the RR intervals of the normal and congestive heart failure (CHF) subjects (available via www.physionet.org) and show that there is a good degree of separation between the two groups.

Govindan, R. B.; Wilson, J. D.; Eswaran, H.; Lowery, C. L.; Preißl, H.

2007-03-01

402

Forensic seismology revisited  

NASA Astrophysics Data System (ADS)

The first technical discussions, held in 1958, on methods of verifying compliance with a treaty banning nuclear explosions, concluded that a monitoring system could be set up to detect and identify such explosions anywhere except underground: the difficulty with underground explosions was that there would be some earthquakes that could not be distinguished from an explosion. The development of adequate ways of discriminating between earthquakes and underground explosions proved to be difficult so that only in 1996 was a Comprehensive Nuclear Test Ban Treaty (CTBT) finally negotiated. Some of the important improvements in the detection and identification of underground tests—that is in forensic seismology—have been made by the UK through a research group at the Atomic Weapons Establishment (AWE). The paper describes some of the advances made in identification since 1958, particularly by the AWE Group, and the main features of the International Monitoring System (IMS), being set up to verify the Test Ban. Once the Treaty enters into force, then should a suspicious disturbance be detected the State under suspicion of testing will have to demonstrate that the disturbance was not a test. If this cannot be done satisfactorily the Treaty has provisions for on-site inspections (OSIs): for a suspicious seismic disturbance for example, an international team of inspectors will search the area around the estimated epicentre of the disturbance for evidence that a nuclear test really took place. Early observations made at epicentral distances out to 2,000 km from the Nevada Test Site showed that there is little to distinguish explosion seismograms from those of nearby earthquakes: for both source types the short-period (SP: ˜1 Hz) seismograms are complex showing multiple arrivals. At long range, say 3,000 10,000 km, loosely called teleseismic distances, the AWE Group noted that SP P waves—the most widely and well-recorded waves from underground explosions—were in contrast simple, comprising one or two cycles of large amplitude followed by a low-amplitude coda. Earthquake signals on the other hand were often complex with numerous arrivals of similar amplitude spread over 35 s or more. It therefore appeared that earthquakes could be recognised on complexity. Later however, complex explosion signals were observed which reduced the apparent effectiveness of complexity as a criterion for identifying earthquakes. Nevertheless, the AWE Group concluded that for many paths to teleseismic distances, Earth is transparent for P signals and this provides a window through which source differences will be most clearly seen. Much of the research by the Group has focused on understanding the influence of source type on P seismograms recorded at teleseismic distances. Consequently the paper concentrates on teleseismic methods of distinguishing between explosions and earthquakes. One of the most robust criteria for discriminating between earthquakes and explosions is the m b : M s criterion which compares the amplitudes of the SP P waves as measured by the body-wave magnitude m b, and the long-period (LP: ˜0.05 Hz) Rayleigh-wave amplitude as measured by the surface-wave magnitude M s; the P and Rayleigh waves being the main wave types used in forensic seismology. For a given M s, the m b for explosions is larger than for most earthquakes. The criterion is difficult to apply however, at low magnitude (say m b < 4.5) and there are exceptions—earthquakes that look like explosions. A difficulty with identification criteria developed in the early days of forensic seismology was that they were in the main empirical—it was not known why they appeared to work and if there were test sites or earthquakes where they would fail. Consequently the AWE Group in cooperation with the University of Cambridge used seismogram modelling to try and understand what controls complexity of SP P seismograms, and to put the m b : M s criterion on a theoretical basis. The results of this work show that the m b : M s criterion is robust because several factors con

Douglas, A.

2007-01-01

403

Chemical surface inhomogeneities in late B-type stars with Hg and Mn peculiarity. I. Spot evolution in HD 11753 on short and long time scales  

NASA Astrophysics Data System (ADS)

Aims: Time series of high-resolution spectra of the late B-type star HD 11753 exhibiting HgMn chemical peculiarity are used to study the surface distribution of different chemical elements and their temporal evolution. Methods: High-resolution and high signal-to-noise ratio spectra were obtained using the CORALIE spectrograph at La Silla in 2000, 2009, and 2010. Surface maps of Y ii, Sr ii, Ti ii, and Cr ii were calculated using the Doppler imaging technique. The results were also compared to equivalent width measurements. The evolution of chemical spots both on short and long time scales were investigated. Results: We determine the binary orbit of HD 11753 and fine-tune the rotation period of the primary. The earlier discovered fast evolution of the chemical spots is confirmed by an analysis using both the chemical spot maps and equivalent width measurements. In addition, a long-term decrease in the overall Y ii and Sr ii abundances is discovered. A detailed analysis of the chemical spot configurations reveals some possible evidence that a very weak differential rotation is operating in HD 11753. Based on observations obtained with the CORALIE Échelle Spectrograph on the 1.2-m Euler Swiss telescope, situated at La Silla, Chile; based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programmes 076.D-0172 and 077.D-0477; and based on data obtained from the ESO Science Archive Facility under request number HHKorhonen15448.Table 2 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/553/A27Table 1 and Figs. 12-19, 22, and 23 are available in electronic form at http://www.aanda.org

Korhonen, H.; González, J. F.; Briquet, M.; Flores Soriano, M.; Hubrig, S.; Savanov, I.; Hackman, T.; Ilyin, I. V.; Eulaers, E.; Pessemier, W.

2013-05-01

404

Gravitational Wave asteroseismology revisited  

E-print Network

The frequencies and damping times of the non radial oscillations of neutron stars are computed for a set of recently proposed equations of state (EOS) which describe matter at supranuclear densites. These EOS are obtained within two different approaches, the nonrelativistic nuclear many-body theory and the relativistic mean field theory, that model hadronic interactions in different ways leading to different composition and dynamics. Being the non radial oscillations associated to the emission of gravitational waves, we fit the eigenfrequencies of the fundamental mode and of the first pressure and gravitational-wave mode (polar and axial) with appropriate functions of the mass and radius of the star, comparing the fits, when available, with those obtained by Andersson and Kokkotas in 1998. We show that the identification in the spectrum of a detected gravitational signal of a sharp pulse corresponding to the excitation of the fundamental mode or of the first p-mode, combined with the knowledge of the mass of the star - the only observable on which we may have reliable information - would allow to gain interesting information on the composition of the inner core. We further discuss the detectability of these signals by gravitational detectors.

O. Benhar; V. Ferrari; L. Gualtieri

2004-07-26

405

Hotspot swells revisited  

NASA Astrophysics Data System (ADS)

The first attempts to quantify the width and height of hotspot swells were made more than 30 years ago. Since that time, topography, ocean-floor age, and sediment thickness datasets have improved considerably. Swell heights and widths have been used to estimate the heat flow from the core-mantle boundary, constrain numerical models of plumes, and as an indicator of the origin of hotspots. In this paper, we repeat the analysis of swell geometry and buoyancy flux for 54 hotspots, including the 37 considered by Sleep (1990) and the 49 considered by Courtillot et al. (2003), using the latest and most accurate data. We are able to calculate swell geometry for a number of hotspots that Sleep was only able to estimate by comparison with other swells. We find that in spite of the increased resolution in global bathymetry models there is significant uncertainty in our calculation of buoyancy fluxes due to differences in our measurement of the swells’ width and height, the integration method (volume integration or cross-sectional area), and the variations of the plate velocities between HS2-Nuvel1a (Gripp and Gordon, 1990) and HS3-Nuvel1a (Gripp and Gordon, 2002). We also note that the buoyancy flux for Pacific hotspots is in general larger than for Eurasian, North American, African and Antarctic hotspots. Considering that buoyancy flux is linearly related to plate velocity, we speculate that either the calculation of buoyancy flux using plate velocity over-estimates the actual vertical flow of material from the deep mantle or that convection in the Pacific hemisphere is more vigorous than the Atlantic hemisphere.

King, Scott D.; Adam, Claudia

2014-10-01

406

The Armstrong experiment revisited  

NASA Astrophysics Data System (ADS)

When a high-voltage direct-current is applied to two beakers filled with water or polar liquid dielectrica, a horizontal bridge forms between the two beakers. This experiment was first carried out by Lord Armstrong in 1893 and then forgotten until recently. Such bridges are stable by the action of electrohydrodynamic (EHD) forces caused by electric field gradients counteracting gravity. Due to these gradients a permanent pumping of liquid from one beaker into the other is observed. At macroscopic scale several of the properties of a horizontal water bridge can be explained by modern electrohydrodynamics, analyzing the motion of fluids in electric fields. Whereas on the molecular scale water can be described by quantum mechanics, there is a conceptual gap at mesoscopic scale which is bridged by a number of theories including quantum mechanical entanglement and coherent structures in water - theories that we discuss here. Much of the phenomenon is already understood, but even more can still be learned from it, since such "floating" liquid bridges resemble a small high voltage laboratory of their own: The physics of liquids in electric fields of some kV/cm can be studied, even long time experiments like neutron or light scattering are feasible since the bridge is in a steady-state equilibrium and can be kept stable for hours. It is also an electro-chemical reactor where compounds are transported through by the EHD flow, enabling the study of electrochemical reactions under potentials which are otherwise not easily accessible. Last but not least the bridge provides the experimental biologist with the opportunity to expose living organisms such as bacteria to electric fields without killing them, but with a significant influence on their behavior, and possibly, even on their genome.

Fuchs, Elmar C.; Wexler, Adam D.; Paulitsch-Fuchs, Astrid H.; Agostinho, Luewton L. F.; Yntema, Doekle; Woisetschläger, Jakob

2014-04-01

407

MetaVelvet: An Extension of Velvet Assembler to de novo Metagenome Assembly from Short Sequence Reads (Metagenomics Informatics Challenges Workshop: 10K Genomes at a Time)  

SciTech Connect

Keio University's Yasumbumi Sakakibara on "MetaVelvet: An Extension of Velvet Assembler to de novo Metagenome Assembly from Short Sequence Reads" at the Metagenomics Informatics Challenges Workshop held at the DOE JGI on October 12-13, 2011.

Sakakibara, Yasumbumi [Keio University] [Keio University

2011-10-13

408

169 invasion of murine annexin A1 in bovine ovarian cortex tissue during short-time xenotransplantation in conventional and immune deficient mice.  

PubMed

In 2012, 6.7 million women worldwide were diagnosed with cancer, including young women and children. Almost 85% of the latter survive the disease. However, the necessary cytotoxic treatment reduces their reproductive potential by damaging the stock of, basically preantral, ovarian follicles. Current fertility preservation techniques try to overcome this problem. Still, the success rate is low due to a lack of optimization and standardization. Nowadays, culturing preantral follicles in vitro is not yet routinely possible. Therefore, we used an in vivo model based on xenotransplantation of bovine ovarian cortex tissue in recipient mice, as an alternative to studying human reproduction. To further characterise this model, we assessed the influence from the host on the graft at the protein level. Visualising murine annexin A1, an anti-inflammatory protein, in the transplanted bovine cortex tissue should help to elucidate the process of immunological rejection. Hereto its distribution around the present bovine follicles is measured. In total, 12 mice (6 conventional fluorescent C57BL/6-eGFP and 6 immune deficient Balb/c-Nu) were used as graft recipients. All mice were anesthetized with an intraperitoneal injection and subsequently sterilized. Small pieces (max. 9mm(3)) of adult bovine ovarian cortex, retrieved from slaughterhouse ovaries, were grafted retroperitoneal. After a transplantation period of 14 (3 mice/mice strain) or 28 (3 mice/mice strain) days, the mice were killed and all grafts were successfully recovered. These were fixed (4% formaldehyde) and processed into histological paraffin slides. Murine annexin A1 (Sigma-Aldrich HPA011271) was localised using immunofluorescence through a rhodamine label (RITC filter). We measured the shortest distances between 10 annexin fluorescent signals and the basal membrane of each follicle, found in the graft. We calculated the average of these measurements, resulting in one data point per follicle. The dataset was fitted in a linear mixed model with annexin as dependent variable, and transplantation period and mice strain as fixed effects. Fluorescent signals of murine annexin A1 were found in all grafts form both mice strains, surrounding bovine follicles. Data show no interaction between mice strain and the duration of the transplantation period. The influence of the mice strain showed a trend towards significance (P=0.08), possibly due to the immunological state of the host. To our knowledge, this is the first time an attempt has been made to characterise the host/donor interaction in xenografting procedures. We can conclude that annexin A1 from the murine host (whether immunodeficient or immunocompetent) invades the bovine graft tissue in a short period of time. PMID:25472218

Bartholomeus, E; Langbeen, A; Leblon, D; Fransen, E; Ponsaerts, P; Leroy, J L M R; Bols, P E J

2014-12-01

409

Inactivation of Bacillus anthracis spores by a combination of biocides and heating under high-temperature short-time pasteurization conditions.  

PubMed

The milk supply is considered a primary route for a bioterrorism attack with Bacillus anthracis spores because typical high-temperature short-time (HTST) pasteurization conditions cannot inactivate spores. In the event of intentional contamination, an effective method to inactivate the spores in milk under HTST processing conditions is needed. This study was undertaken to identify combinations and concentrations of biocides that can inactivate B. anthracis spores at temperatures in the HTST range in less than 1 min. Hydrogen peroxide (HP), sodium hypochlorite (SH), and peroxyacetic acid (PA) were evaluated for their efficacy in inactivating spores of strains 7702, ANR-1, and 9131 in milk at 72, 80, and 85 degrees C using a sealed capillary tube technique. Strains ANR-1 and 9131 were more resistant to all of the biocide treatments than strain 7702. Addition of 1,260 ppm SH to milk reduced the number of viable spores of each strain by 6 log CFU/ml in less than 90 and 60 s at 72 and 80 degrees C, respectively. After neutralization, 1,260 ppm SH reduced the time necessary to inactivate 6 log CFU/ml (TTI6-log) at 80 degrees C to less than 20 s. Treatment of milk with 7,000 ppm HP resulted in a similar level of inactivation in 60 s. Combined treatment with 1,260 ppm SH and 1,800 ppm HP inactivated spores of all strains in less than 20 s at 80 degrees C. Mixing 15 ppm PA with milk containing 1,260 ppm SH resulted in TTI6-log of 25 and 12 s at 72 and 80 degrees C, respectively. TTI6-log of less than 20 s were also achieved at 80 degrees C by using two combinations of biocides: 250 ppm SH, 700 ppm HP, and 150 ppm PA; and 420 ppm SH (pH 7), 1,100 ppm HP, and 15 ppm PA. These results indicated that different combinations of biocides could consistently result in 6-log reductions in the number of B. anthracis spores in less than 1 min at temperatures in the HTST range. This information could be useful for developing more effective thermal treatment strategies which could be used in HTST milk plants to process contaminated milk for disposal and decontamination, as well as for potential protective measures. PMID:18390680

Xu, Sa; Labuza, Theodore P; Diez-Gonzalez, Francisco

2008-06-01

410

Advanced chemistry-transport modeling and observing systems allow daily air quality observations, short-term forecasts, and real-time analyses of air quality at the global and  

E-print Network

Advanced chemistry-transport modeling and observing systems allow daily air quality observations, short-term forecasts, and real-time analyses of air quality at the global and European scales control measures that could be taken for managing such episodes, European-scale air quality forecasting

Paris-Sud XI, Université de

411

Short Circuit  

NSDL National Science Digital Library

In this activity about electricity, learners explore what happens when you blow a fuse. Learners short-circuit a battery using copper wire (a good conductor with very low resistance) and thin iron wire. Learners will discover that when they connect the clip to the iron wire, the voltage of the battery pushes electrons through the circuit against the resistance of the iron wire, causing the iron wire to heat up. Note: the wire gets very hot! Use this activity to introduce learners to basics of electricity including conductivity, resistance, and currents as well as electronics safety and circuit breakers.

Exploratorium, The

2011-12-02

412

Cholesterol and vitamins: revisited study.  

PubMed

The link between low density lipoprotein and coronary heart disease has been widely studied. Oxidized LDL damages the artery wall, and a diet rich in vitamins and low in saturated fat and cholesterol may reduce this risk. Not only hypercholesterolemia but also low levels of high density lipoprotein cholesterol are critical risk factors for atherosclerosis and related diseases. It has been reported that high doses of B complex vitamin may be useful in lowering blood cholesterol and triglyceride levels in the body, however the use of this compound has been limited by an annoying flush and concern for toxicity. Niacin is a B-complex vitamin with anti-atherosclerotic properties and is an effective medication for raising high density lipoprotein. The combination of niacin with other lipid-lowering drugs, such as statins, reduces the dynamic of atherosclerosis disease. In addition, vitamin E is one of the most important lipid soluble anti-oxidants in humans, and reduces atherosclerosis plaque, coronary artery diseases and myocardial infarction. Vitamin E protects the integrity of membranes by inhibiting lipid peroxidation. In this study we revisited the interrelationship between cholesterol, low density lipoproteins and vitamins. PMID:22217984

Saggini, A; Anogeianaki, A; Angelucci, D; Cianchetti, E; D'Alessandro, M; Maccauro, G; Salini, V; Caraffa, A; Teté, S; Conti, F; Tripodi, D; Fulcheri, M; Frydas, S; Shaik-Dasthagirisaheb, Y B

2011-01-01

413

The mycorrhiza helper bacteria revisited.  

PubMed

In natural conditions, mycorrhizal fungi are surrounded by complex microbial communities, which modulate the mycorrhizal symbiosis. Here, the focus is on the so-called mycorrhiza helper bacteria (MHB). This concept is revisited, and the distinction is made between the helper bacteria, which assist mycorrhiza formation, and those that interact positively with the functioning of the symbiosis. After considering some examples of MHB from the literature, the ecological and evolutionary implications of the relationships of MHB with mycorrhizal fungi are discussed. The question of the specificity of the MHB effect is addressed, and an assessment is made of progress in understanding the mechanisms of the MHB effect, which has been made possible through the development of genomics. Finally, clear evidence is presented suggesting that some MHB promote the functioning of the mycorrhizal symbiosis. This is illustrated for three critical functions of practical significance: nutrient mobilization from soil minerals, fixation of atmospheric nitrogen, and protection of plants against root pathogens. The review concludes with discussion of future research priorities regarding the potentially very fruitful concept of MHB. PMID:17803639

Frey-Klett, P; Garbaye, J; Tarkka, M

2007-01-01

414

Revisiting Bohr's semiclassical quantum theory.  

PubMed

Bohr's atomic theory is widely viewed as remarkable, both for its accuracy in predicting the observed optical transitions of one-electron atoms and for its failure to fully correspond with current electronic structure theory. What is not generally appreciated is that Bohr's original semiclassical conception differed significantly from the Bohr-Sommerfeld theory and offers an alternative semiclassical approximation scheme with remarkable attributes. More specifically, Bohr's original method did not impose action quantization constraints but rather obtained these as predictions by simply matching photon and classical orbital frequencies. In other words, the hydrogen atom was treated entirely classically and orbital quantized emerged directly from the Planck-Einstein photon quantization condition, E = h nu. Here, we revisit this early history of quantum theory and demonstrate the application of Bohr's original strategy to the three quintessential quantum systems: an electron in a box, an electron in a ring, and a dipolar harmonic oscillator. The usual energy-level spectra, and optical selection rules, emerge by solving an algebraic (quadratic) equation, rather than a Bohr-Sommerfeld integral (or Schroedinger) equation. However, the new predictions include a frozen (zero-kinetic-energy) state which in some (but not all) cases lies below the usual zero-point energy. In addition to raising provocative questions concerning the origin of quantum-chemical phenomena, the results may prove to be of pedagogical value in introducing students to quantum mechanics. PMID:17020371

Ben-Amotz, Dor

2006-10-12

415

Phytoplankton size structure and primary production in a highly dynamic coastal ecosystem (Ría de Vigo, NW-Spain): Seasonal and short-time scale variability  

NASA Astrophysics Data System (ADS)

Size-fractionated phytoplankton biomass and primary production, together with net community metabolism, were measured in a coastal ecosystem (Ría de Vigo, NW-Spain) during a full annual cycle (July 2001-July 2002). On a seasonal scale, this ecosystem was characterized by two distinct oceanographic conditions, namely upwelling and downwelling favourable seasons. During the upwelling season, total chlorophyll a (Chl a) and particulate organic carbon production rates (POC-pr) were in the range 36-129 mg Chl a m -2 and 89-834 mg C m -2 h -1, respectively, and were mainly accounted for (>80%) by the microphytoplankton size fraction (>20 ?m). During the downwelling season, total Chl a and POC-pr were much lower (<27 mg Chl a m -2 and <97 mg C m -2 h -1, respectively), and the pico- (<2 ?m) and nano- (2-20 ?m) phytoplankton size fractions significantly increased their contribution to total Chl a (46-87%) and POC-pr (30-86%). The seasonal and short-time scale variability in the hydrographic conditions, in particular upwelling intermittency, provides a feasible explanation for the continuous dominance of large-sized phytoplankton during the upwelling period. Shelf water intrusions, continuous vertical mixing and the size-dependent limitation in light acquisition (package effect), suffered in a higher degree by larger phytoplankton, were likely to account for the shift in phytoplankton size structure during the downwelling period. During the upwelling season, community respiration represented a minor fraction of gross primary production (15-30%), which highlights the large export potential of organic matter by this ecosystem. On the contrary, community respiration accounted for a major fraction of primary production (85%) during the downwelling period, which suggests that most of the photosynthesised organic matter was remineralised within the ecosystem. Although the microbial plankton community of the Ría de Vigo exhibits a net autotrophic functioning throughout the year, the magnitude of the carbon flows and budgets seems to be dependent on phytoplankton size structure.

Cermeño, Pedro; Marañón, Emilio; Pérez, Valesca; Serret, Pablo; Fernández, Emilio; Castro, Carmen G.

2006-03-01

416

Ant Foraging Revisited Liviu Alexandru Panait1  

E-print Network

Ant Foraging Revisited Liviu Alexandru Panait1 and Sean Luke1 1. Department of Computer Science: lpanait@cs.gmu.edu Abstract Previous artificial (non-biological) ant foraging models have to date relied ants with the knowledge of the nest direction. In contrast, the work presented solves ant foraging

Luke, Sean

417

The Fermat factorization method revisited Robert Erra  

E-print Network

The Fermat factorization method revisited Robert Erra Christophe Grenier 30th June 2009 Abstract We consider the well known Fermat factorization method, we call the Fermat factorization equation the equation works. 1 Introduction Fermat, in a letter to Mersenne around 1643, exposed an algorithm to factor odd

418

Patent Claims Revisited: Examiners and Trolls  

Microsoft Academic Search

In this article, the author revisits the writing of claims, and demonstrates two other styles of writing them. In one style, the author shows how to write a more narrow and focused claim. In the other style, he shows how to write claims that are beyond broad - claims that can be written prior to actually inventing anything. Note that

Philip G. Emma

2006-01-01

419

HARMONIC TWOSPHERES IN COMPACT SYMMETRIC SPACES, REVISITED  

E-print Network

HARMONIC TWO­SPHERES IN COMPACT SYMMETRIC SPACES, REVISITED F. E. Burstall and M. A. Guest Introduction The purpose of this article is to give a new description of harmonic maps from the two­sphere S 2 of such harmonic maps occur when G=K = S n or CP n . In 1967, E. Calabi gave a construction of all harmonic maps

Bath, University of

420

Biodiversity measures revisited Natalia Petrovskaya a  

E-print Network

Biodiversity measures revisited Natalia Petrovskaya a , Sergei Petrovskii b,c,*, Bai-Lian Li c, Riverside, CA 92521-0124, USA 1. Introduction Loss of biodiversity in various ecosystems all over the world to recognize the main threats for communities functioning and reasons for biodiversity loss; examples

Petrovskaya, Natalia B.

421

Common Knowledge Revisited \\Lambda Ronald Fagin  

E-print Network

that in order for something to be a convention, it must in fact be common knowledge among the members of a group #12; convention that green means ``go'' and red means ``stop'' is presumably common knowledge amongCommon Knowledge Revisited \\Lambda Ronald Fagin IBM Almaden Research Center 650 Harry Road San Jose

Vardi, Moshe Y.

422

Revisitation patterns in World Wide Web navigation  

Microsoft Academic Search

We report on users' revisitation patterns to World Wide Web pages, and use these to lay an empirical foundation for the design of history mechanisms in web browsers. Through history, a user can return quickly to a previously visited page, possibly reducing the cognitive and physical overhead required to navigate to it from scratch. We analyzed 6 weeks of usage

Linda Tauscher; Saul Greenberg

1997-01-01

423

Revisiting the Definition of Homo Sapiens  

Microsoft Academic Search

Research in genomics, human cloning, and transgenic technology has challenged bioethicists and scientists to rethink the definition of human be- ings as a species. For example, should the definition incorporate a genetic crite- rion and how does the capacity to genetically engineer human beings affect the definition of our species? In considering these contemporary bioethical dilem- mas, we revisit an

John D. Loike; Moshe David Tendler

2002-01-01

424

Internal waves revisited B.R. Sutherland  

E-print Network

Internal waves revisited B.R. Sutherland , G.O. Hughes y, S.B. Dalziel and P.F. Linden z Department and amplitude of internal waves. As well as being relatively inexpensive to set up, the technique is sensitive to small density uctuations: heat rising from a hand can easily be seen. If the internal wave eld

Sutherland, Bruce

425

The Rotating Morse-Pekeris Oscillator Revisited  

ERIC Educational Resources Information Center

The Morse-Pekeris oscillator model for the calculation of the vibration-rotation energy levels of diatomic molecules is revisited. This model is based on the realization of a second-order exponential expansion of the centrifugal term about the minimum of the vibrational Morse oscillator and the subsequent analytical resolution of the resulting…

Zuniga, Jose; Bastida, Adolfo; Requena, Alberto

2008-01-01

426

South Africa: Revisiting Capital's ‘Formative Action’  

Microsoft Academic Search

This article revisits Saul and Gelb's 1981 analysis of South African capital's ‘formative action’, employing their framework to assess how capital hasshaped the economic framework since 1990. I show that once prominentbusiness leaders became committed to non?racial democracy, the privatesector became enormously influential in shaping the economic programme.The policy changes permitted South African firms to restructure theiroperations largely on their

Carolyn Bassett

2008-01-01

427

Empirically Revisiting the Test Independence Assumption  

E-print Network

Empirically Revisiting the Test Independence Assumption Sai Zhang, Darioush Jalali, Jochen Wuttke}@cs.washington.edu ABSTRACT In a test suite, all the test cases should be independent: no test should affect any other test's result, and running the tests in any order should produce the same test results. Techniques such as test

Ernst, Michael

428

Women's Place, Revisited (NYT) 421 words  

E-print Network

Women's Place, Revisited (NYT) 421 words Published: January 19, 2006 The election on Sunday of Michelle Bachelet as Chile's president completes a three- continent long jump for women in politics. Ms strongman. On Monday, when Ellen Johnson Sirleaf was inaugurated as president of Liberia, she became Africa

Lopez-Carr, David

429

Security of Invertible Media Authentication Schemes Revisited  

Microsoft Academic Search

Dittmann, Katzenbeisser, Schallhart and Veith (IACR ePrint 2004) intro- duced the notion of invertible media authentication schemes, embedding authentication data in media objects via invertible watermarks. These invertible watermarks allow to recover the original media object (given a secret encryption key), as required for example in some medical applications where the distortion must be removable. Here we revisit the approach

Daniel Dönigus; Stefan Endler; Marc Fischlin; Andreas Hülsing; Patrick Jäger; Anja Lehmann; Sergey Podrazhansky; Sebastian Schipp; Erik Tews; Sven Vowe; Matthias Walthart; Frederik Weidemann

2007-01-01

430

ORIGINAL ARTICLE Cytosolic potassium homeostasis revisited: 42  

E-print Network

ORIGINAL ARTICLE Cytosolic potassium homeostasis revisited: 42 K-tracer analysis in Hordeum vulgare of the flexibility, rather than strict homeostasis, of cellular K+ maintenance, and of the dynamic interaction analysis Ã? 42 K Ã? Hordeum Ion transport Ã? Homeostasis Introduction Potassium (K+ ) availability in both

Britto, Dev T.

431

Navjot's nightmare revisited: logging, agriculture, and biodiversity  

E-print Network

tremendous biodiversity loss. This loss is exac- erbated by increased fire frequency. Therefore, we conNavjot's nightmare revisited: logging, agriculture, and biodiversity in Southeast Asia David S Raffles Museum of Biodiversity Research, National University of Singapore, 117546, Singapore 3 Centre

Vermont, University of

432

Revisiting Fascist Italy's Crime in Ethiopia ? I???? ???  

Microsoft Academic Search

This essay will make a brief historical synopsis and analysis of the crimes perpetrated by the Italian fascists against the Ethiopian people in the 1930s. At this particular juncture, it may sound ironic to revisit the crimes against humanity committed in Ethiopia by Fascist henchmen like Marshall Pietro Badoglio and Marshal Rodolfo Graziani, but sometimes the past contends with the

Ghelawdewos Araia

433

Smith Theory Revisited William G. Dwyer  

E-print Network

Smith Theory Revisited William G. Dwyer Clarence W. Wilkerson \\Lambda 1 Introduction In the late 1930's, P. A. Smith began the investigation of the cohomological properties of a group G of prime order fifty years. Smith was successful in calculating the cohomology of the the fixed point sets

Wilkerson, Clarence

434

Smith Theory Revisited William G. Dwyer  

E-print Network

Smith Theory Revisited William G. Dwyer Clarence W. Wilkerson 1 Introduction In the late 1930's, P. A. Smith began the investigation of the cohomological properties of a group G of prime order p. Smith was successful in calculating the cohomology of the the fixed point sets for involutions

Wilkerson, Clarence

435

DWORKIN'S ARGUMENT REVISITED: POINT PROCESSES, DYNAMICS, DIFFRACTION,  

E-print Network

********************************************** DWORKIN'S ARGUMENT REVISITED: POINT PROCESSES, DYNAMICS, DIFFRACTION, AND CORRELATIONS XINGHUA DENG sets by the vectors of Rd . Steven Dworkin's argument relates the diffraction of the typical point sets space of Rd under the diffraction measure into L2 (X, µ). We examine the image of this embedding

Moody, Robert Vaughan

436

Revisiting the Skills Agenda: A Complicated Geography  

ERIC Educational Resources Information Center

This paper revisits the skills agenda and suggests that in light of shifts from supply-side to demand-led provision within the UK higher education sector, there is a need to think more critically about the role and place of skills within university curricula. It suggests that if universities are to respond effectively to sector changes, then the…

Saunders, Angharad

2011-01-01

437

Time differences in the emergence of short- and long-term memory during post-embryonic development in the cuttlefish, Sepia  

Microsoft Academic Search

When shown prawns in a glass tube, cuttlefish quickly learn to inhibit their predatory behaviour. The available literature suggests that cuttlefish show an excellent retention between 2 and 8 min, a recovery of the predatory responses around 20 min, and good retention after 1 h of the training phase. These results have been interpreted as the product of separate short-

Ludovic Dickel; Marie-Paule Chichery; Raymond Chichery

1998-01-01

438

Screening Li-Ion Batteries for Internal Shorts  

NASA Technical Reports Server (NTRS)

The extremely high cost of aerospace battery failures due to internal shorts makes it essential that their occurrence be very rare, if not eliminated altogether. With Li-ion cells/batteries, the potentially catastrophic safety hazard that some internal shorts present adds additional incentive for prevention. Prevention can be achieved by design, manufacturing measures, and testing. Specifically for NASA s spacesuit application, a Li-ion polymer pouch cell battery design is in its final stages of production. One of the 20 flight batteries fabricated and tested developed a cell internal short, which did not present a safety hazard, but has required revisiting the entire manufacturing and testing process. Herein are the details of the failure investigation that followed to get to root cause of the internal short and the corrective actions that will be taken. The resulting lessons learned are applicable to most Li-ion battery applications.

Darcy, Eric

2006-01-01

439

Time  

ERIC Educational Resources Information Center

When a teacher gives their time to a student, it is more significant to that student than anything else one could do for him or her. Music teachers deal with time all the time. Someone once said that "time is like money: we never have enough." This may seem true; however, time is not like money. One can make more money, but one cannot "make time."…

Circle, David

2005-01-01

440

Measurement of short bunches  

SciTech Connect

In recent years, there has been increasing interest in short electron bunches for different applications such as short wavelength FELs, linear colliders, and advanced accelerators such as laser or plasma wakefield accelerators. One would like to meet various requirements such as high peak current, low momentum spread, high luminosity, small ratio of bunch length to plasma wavelength, and accurate timing. Meanwhile, recent development and advances in RF photoinjectors and various bunching schemes make it possible to generate very short electron bunches. Measuring the longitudinal profile and monitoring bunch length are critical to understand the bunching process and longitudinal beam dynamics, and to commission and operate such short bunch machines. In this paper, several commonly used measurement techniques for subpicosecond bunches and their relative advantages and disadvantages are discussed. As examples, bunch length related measurements at Jefferson lab are presented. At Jefferson Lab, bunch lengths s short as 84 fs have been systematically measured using a zero-phasing technique. A highly sensitive Coherent Synchrotron Radiation (CSR) detector has been developed to noninvasively monitor bunch length for low charge bunches. Phase transfer function measurements provide a means of correcting RF phase drifts and reproducing RF phases to within a couple of tenths of a degree. The measurement results are in excellent agreement with simulations. A comprehensive bunch length control scheme is presented.

Wang, D.X.

1996-10-01

441

Long and short fiber amosite asbestos alters at a different extent the redox metabolism in human lung epithelial cells  

Microsoft Academic Search

The mechanism by which asbestos fibers are fibrogenic and tumorigenic is still matter of debate. The higher pathogenicity of longer fibers has been traditionally associated with their slower clearance in respiratory airways. However, short amosite fibers, obtained by grinding longer ones, exhibited a lower potential to damage nude DNA and a lower in vitro cytotoxicity. We have thus revisited the

Chiara Riganti; Elisabetta Aldieri; Loredana Bergandi; Maura Tomatis; Ivana Fenoglio; Costanzo Costamagna; Bice Fubini; Amalia Bosia; Dario Ghigo

2003-01-01

442

Free software, Open source software, licenses. A short presentation including a procedure for research software and data dissemination  

E-print Network

Free software, Open source software, licenses. A short presentation including a procedure for research software and data dissemination T. Gomez-Diaz CNRS, Universit´e Paris-Est, Laboratoire d to revisit the basic concepts in software distribution such as free software, open source software, licenses

443

Unit-specific event-based continuous-time approach for short-term scheduling of batch plants using RTN framework  

Microsoft Academic Search

The problem of short-term scheduling of batch plants has received remarkable attention in the past two decades. The state-task-network (STN) and resource-task-network (RTN) process representations are extensively used in modeling scheduling problems. In this paper, we propose a new model to investigate the RTN representation for unit-specific event-based models. For handling dedicated finite storage, a novel formulation is proposed without

Munawar A. Shaik; Christodoulos A. Floudas

2008-01-01

444

Associations between in-hospital bed occupancy and unplanned 72-h revisits to the emergency department: a register study  

PubMed Central

Background A possible downstream effect of high in-hospital bed occupancy is that patients in the emergency department (ED) who would benefit from in-hospital care are denied admission. The present study aimed at evaluating this hypothesis through investigating associations between in-hospital bed occupancy at the time of presentation in the ED and the probability for unplanned 72-hour (72-h) revisits to the ED among patients discharged at index. A second outcome was unplanned 72-h revisits resulting in admission. Methods All visits to the ED of a 420-bed emergency hospital in southern Sweden between 1 January 2011 and 31 December 2012, which did not result in admission, death, or transfer to another hospital were included. Revisiting fractions were computed for in-hospital occupancy intervals <85%, 85% to 90%, 90% to 95%, 95% to 100%, 100% to 105%, and ?105%. Multivariate models were constructed in an attempt to take confounding factors from, e.g., presenting complaints, age, referral status, and triage priority into account. Results Included in the study are 81,878 visits. The fraction of unplanned 72-h revisits/unplanned 72-h revisits resulting in admission was 5.8%/1.4% overall, 6.2%/1.4% for occupancy <85%, 6.4%/1.5% for occupancy 85% to 90%, 5.8%/1.4% for occupancy 90% to 95%, 6.0%/1.6% for occupancy 95% to 100%, 5.4%/1.6% for occupancy 100% to 105%, and 4.9%/1.4% for occupancy ?105%. In the multivariate models, a trend to lower probability of unplanned 72-h revisits was observed at occupancy ?105% compared to occupancy <95% (OR 0.88, CI 0.76 to 1.01). No significant associations between in-hospital occupancy at index and the probability of making unplanned 72-h revisits resulting in admission were observed. Conclusions The lack of associations between in-hospital occupancy and unplanned 72-h revisits does not support the hypothesis that ED patients are inappropriately discharged when in-hospital beds are scarce. The results are reassuring as they indicate that physicians are able to make good decisions, also while resources are constrained. PMID:25045408

2014-01-01

445

Revisiting symmetries of lattice fermions via spin-flavor representation  

E-print Network

Employing the spin-flavor representation, we investigate the structures of the doubler-mixing symmetries and the mechanisms of their spontaneous breakdown in four types of lattice fermion formulation. We first revisit the $U(4)\\timesU(4)A$ symmetries of the naive fermion with the vanishing bare mass m, and re-express them in terms of the spin-flavor representation. We apply the same method to the Wilson fermion, which possesses only the U(1) vector symmetry for general values of m. For a special value of m, however, there emerges an additional U(1) symmetry to be broken by pion condensation. We also explore two types of minimally doubled fermion, and discover a similar kind of symmetry enhancement and its spontaneous breakdown.

Taro Kimura; Shota Komatsu; Tatsuhiro Misumi; Toshifumi Noumi; Shingo Torii; Sinya Aoki

2011-12-23

446

Closing in on a Short-Hard Burst Progenitor: Constraints From Early-Time Optical Imaging and Spectroscopy of a Possible Host Galaxy of GRB 050509b  

SciTech Connect

The localization of the short-duration, hard-spectrum gamma-ray burst GRB050509b by the Swift satellite was a watershed event. Never before had a member of this mysterious subclass of classic GRBs been rapidly and precisely positioned in a sky accessible to the bevy of ground-based follow-up facilities. Thanks to the nearly immediate relay of the GRB position by Swift, we began imaging the GRB field 8 minutes after the burst and have continued during the 8 days since. Though the Swift X-ray Telescope (XRT) discovered an X-ray afterglow of GRB050509b, the first ever of a short-hard burst, thus far no convincing optical/infrared candidate afterglow or supernova has been found for the object. We present a re-analysis of the XRT afterglow and find an absolute position of R.A. = 12h36m13.59s, Decl. = +28{sup o}59'04.9'' (J2000), with a 1{sigma} uncertainty of 3.68'' in R.A., 3.52'' in Decl.; this is about 4'' to the west of the XRT position reported previously. Close to this position is a bright elliptical galaxy with redshift z = 0.2248 {+-} 0.0002, about 1' from the center of a rich cluster of galaxies. This cluster has detectable diffuse emission, with a temperature of kT = 5.25{sub -1.68}{sup +3.36} keV. We also find several ({approx}11) much fainter galaxies consistent with the XRT position from deep Keck imaging and have obtained Gemini spectra of several of these sources. Nevertheless we argue, based on positional coincidences, that the GRB and the bright elliptical are likely to be physically related. We thus have discovered reasonable evidence that at least some short-duration, hard-spectra GRBs are at cosmological distances. We also explore the connection of the properties of the burst and the afterglow, finding that GRB050509b was underluminous in both of these relative to long-duration GRBs. However, we also demonstrate that the ratio of the blast-wave energy to the {gamma}-ray energy is consistent with that of long-duration GRBs. We thus find plausible evidence that the radiation mechanisms of short-hard bursts could be the same as those of long-duration bursts, albeit with lower energy. Moreover, we argue for a comparable (and high) {gamma}-ray conversion efficiency in long-soft and short-hard GRBs. Based on this analysis, on the location of the GRB (40 {+-} 13 kpc from a bright galaxy), and on the galaxy type (elliptical), we suggest that there is now observational support for the hypothesis that short-hard bursts arise during the merger of a compact binary (two neutron stars, or a neutron star and a black hole). Other progenitor models are still viable, and additional rapidly localized bursts from the Swift mission will undoubtedly help to further clarify the progenitor picture.

Bloom, Joshua S.; Prochaska, J.X.; Pooley, D.; Blake, C.W.; Foley, R.J.; Jha, S.; Ramirez-Ruiz, E.; Granot, J.; Filippenko, A.V.; Sigurdsson, S.; Barth, A.J.; Chen,; Cooper, M.C.; Falco, E.E.; Gal, R.R.; Gerke, B.F.; Gladders, M.D.; Greene, J.E.; Hennanwi, J.; Ho, L.C.; Hurley, K.; /UC, Berkeley, Astron. Dept. /Lick Observ.

2005-06-07