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Sample records for interaural time difference

  1. Speech segregation based-on binaural cue: interaural time difference (itd) and interaural level difference (ild)

    Science.gov (United States)

    Nur Farid, Mifta; Arifianto, Dhany

    2016-11-01

    A person who is suffering from hearing loss can be helped by using hearing aids and the most optimal performance of hearing aids are binaural hearing aids because it has similarities to human auditory system. In a conversation at a cocktail party, a person can focus on a single conversation even though the background sound and other people conversation is quite loud. This phenomenon is known as the cocktail party effect. In an early study, has been explained that binaural hearing have an important contribution to the cocktail party effect. So in this study, will be performed separation on the input binaural sound with 2 microphone sensors of two sound sources based on both the binaural cue, interaural time difference (ITD) and interaural level difference (ILD) using binary mask. To estimate value of ITD, is used cross-correlation method which the value of ITD represented as time delay of peak shifting at time-frequency unit. Binary mask is estimated based on pattern of ITD and ILD to relative strength of target that computed statistically using probability density estimation. Results of sound source separation performing well with the value of speech intelligibility using the percent correct word by 86% and 3 dB by SNR.

  2. Localization by interaural time difference (ITD): Effects of interaural frequency mismatch

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    Bonham, B.H. [Department of Otolaryngology and W. M. Keck Center for Integrative Neuroscience, Box 0732, University of California, San Francisco, California 94143-0732 (United States); Lewis, E.R. [Department of Electrical Engineering and Computer Science, University of California, Berkeley, California 94720 (United States)

    1999-07-01

    A commonly accepted physiological model for lateralization of low-frequency sounds by interaural time delay (ITD) stipulates that binaural comparison neurons receive input from frequency-matched channels from each ear. Here, the effects of hypothetical interaural frequency mismatches on this model are reported. For this study, the cat{close_quote}s auditory system peripheral to the binaural comparison neurons was represented by a neurophysiologically derived model, and binaural comparison neurons were represented by cross-correlators. The results of the study indicate that, for binaural comparison neurons receiving input from one cochlear channel from each ear, interaural CF mismatches may serve to either augment or diminish the effective difference in ipsilateral and contralateral axonal time delays from the periphery to the binaural comparison neuron. The magnitude of this increase or decrease in the effective time delay difference can be up to 400 {mu}s for CF mismatches of 0.2 octaves or less for binaural neurons with CFs between 250 Hz and 2.5 kHz. For binaural comparison neurons with nominal CFs near 500 Hz, the 25-{mu}s effective time delay difference caused by a 0.012-octave CF mismatch is equal to the ITD previously shown to be behaviorally sufficient for the cat to lateralize a low-frequency sound source. {copyright} {ital 1999 Acoustical Society of America.}

  3. Anatomical limits on interaural time differences: An ecological perspective

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    WILLIAM MORRIS HARTMANN

    2014-02-01

    Full Text Available Human listeners, and other animals too, use interaural time differences (ITDto localize sounds. If the sounds are pure tones, a simple frequency factorrelates the ITD to the interaural phase difference (IPD, for which there areknown iso-IPD boundaries, 90$^circ$, 180$^circ$~ldots defining regions ofspatial perception. In this article, iso-IPD boundaries for humans aretranslated into azimuths using a spherical head model, and the calculationsare checked by free-field measurements. The translated boundaries providequantitative tests of an ecological interpretation for the dramatic onset ofITD insensitivity at high frequencies. According to this interpretation, theinsensitivity serves as a defense against misinformation and can be attributedto limits on binaural processing in the brainstem. Calculations show that theecological explanation passes the tests only if the binaural brainstemproperties evolved or developed consistent with heads that are 50% smallerthan current adult heads. Measurements on more realistic head shapes relaxthat requirement only slightly. The problem posed by the discrepancy betweenthe current head size and a smaller, ideal head size was apparently solved bythe evolution or development of central processes that discount large IPDs infavor of interaural level differences. The latter become more important withincreasing head size.

  4. Detection of Interaural Time Differences in the Alligator

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    Carr, Catherine E.; Soares, Daphne; Smolders, Jean; Simon, Jonathan Z.

    2011-01-01

    The auditory systems of birds and mammals use timing information from each ear to detect interaural time difference (ITD). To determine whether the Jeffress-type algorithms that underlie sensitivity to ITD in birds are an evolutionarily stable strategy, we recorded from the auditory nuclei of crocodilians, who are the sister group to the birds. In alligators, precisely timed spikes in the first-order nucleus magnocellularis (NM) encode the timing of sounds, and NM neurons project to neurons in the nucleus laminaris (NL) that detect interaural time differences. In vivo recordings from NL neurons show that the arrival time of phase-locked spikes differs between the ipsilateral and contralateral inputs. When this disparity is nullified by their best ITD, the neurons respond maximally. Thus NL neurons act as coincidence detectors. A biologically detailed model of NL with alligator parameters discriminated ITDs up to 1 kHz. The range of best ITDs represented in NL was much larger than in birds, however, and extended from 0 to 1000 μs contralateral, with a median ITD of 450 μs. Thus, crocodilians and birds employ similar algorithms for ITD detection, although crocodilians have larger heads. PMID:19553438

  5. Effects of Interaural Intensity Difference on the Processing of Interaural Time Difference in the Owl’s Nucleus Laminaris

    OpenAIRE

    Viete, Svenja; Peña, José Luis; Konishi, Masakazu

    1997-01-01

    Interaural time and intensity differences (ITD and IID) are processed independently in the owl’s auditory system. This paper examines whether this independence is established in nucleus laminaris (NL), the first site of ITD processing. A plot of discharge rate against time difference (ITD curve) is sinusoidal in NL. The ITDs that produce the peaks are called the most favorable ITDs, and those that produce the troughs are called the least favorable ITDs. IID had little effect on the discharge ...

  6. The effect of interaural-time-difference fluctuations on apparent source width

    DEFF Research Database (Denmark)

    Käsbach, Johannes; May, Tobias; Oskarsdottir, Gudrun

    2014-01-01

    For the perception of spaciousness, the temporal fluctuations of the interaural time differences (ITDs) and interaural level differences (ILDs) provide important binaural cues. One major characteristic of spatial perception is apparent source width (ASW), which describes the perceived width of a ...

  7. Modelling of human low frequency sound localization acuity demonstrates dominance of spatial variation of interaural time difference and suggests uniform just-noticeable differences in interaural time difference.

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    Rosanna C G Smith

    Full Text Available Sound source localization is critical to animal survival and for identification of auditory objects. We investigated the acuity with which humans localize low frequency, pure tone sounds using timing differences between the ears. These small differences in time, known as interaural time differences or ITDs, are identified in a manner that allows localization acuity of around 1° at the midline. Acuity, a relative measure of localization ability, displays a non-linear variation as sound sources are positioned more laterally. All species studied localize sounds best at the midline and progressively worse as the sound is located out towards the side. To understand why sound localization displays this variation with azimuthal angle, we took a first-principles, systemic, analytical approach to model localization acuity. We calculated how ITDs vary with sound frequency, head size and sound source location for humans. This allowed us to model ITD variation for previously published experimental acuity data and determine the distribution of just-noticeable differences in ITD. Our results suggest that the best-fit model is one whereby just-noticeable differences in ITDs are identified with uniform or close to uniform sensitivity across the physiological range. We discuss how our results have several implications for neural ITD processing in different species as well as development of the auditory system.

  8. Neural maps of interaural time and intensity differences in the optic tectum of the barn owl.

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    Olsen, J F; Knudsen, E I; Esterly, S D

    1989-07-01

    This report describes the binaural basis of the auditory space map in the optic tectum of the barn owl (Tyto alba). Single units were recorded extracellularly in ketamine-anesthetized birds. Unit tuning for interaural differences in timing and intensity of wideband noise was measured using digitally synthesized sound presented through earphones. Spatial receptive fields of the same units were measured with a free field sound source. Auditory units in the optic tectum are sharply tuned for both the azimuth and the elevation of a free field sound source. To determine the binaural cues that could be responsible for this spatial tuning, we measured in the ear canals the amplitude and phase spectra produced by a free field noise source and calculated from these measurements the interaural differences in time and intensity associated with each of 178 locations throughout the frontal hemisphere. For all frequencies, interaural time differences (ITDs) varied systematically and most strongly with source azimuth. The pattern of variation of interaural intensity differences (IIDs) depended on frequency. For low frequencies (below 4 kHz) IID varied primarily with source azimuth, whereas for high frequencies (above 5 kHz) IID varied primarily with source elevation. Tectal units were tuned for interaural differences in both time and intensity of dichotic stimuli. Changing either parameter away from the best value for the unit decreased the unit's response. The tuning of units to either parameter was sharp: the width of ITD tuning curves, measured at 50% of the maximum response with IID held constant (50% tuning width), ranged from 18 to 82 microsecs. The 50% tuning widths of IID tuning curves, measured with ITD held constant, ranged from 8 to 37 dB. For most units, tuning for ITD was largely independent of IID, and vice versa. A few units exhibited systematic shifts of the best ITD with changes in IID (or shifts of the best IID with changes in ITD); for these units, a change in

  9. Temporal weighting of binaural information at low frequencies: Discrimination of dynamic interaural time and level differences.

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    Diedesch, Anna C; Stecker, G Christopher

    2015-07-01

    The importance of sound onsets in binaural hearing has been addressed in many studies, particularly at high frequencies, where the onset of the envelope may carry much of the useful binaural information. Some studies suggest that sound onsets might play a similar role in the processing of binaural cues [e.g., fine-structure interaural time differences (ITD)] at low frequencies. This study measured listeners' sensitivity to ITD and interaural level differences (ILD) present in early (i.e., onset) and late parts of 80-ms pure tones of 250-, 500-, and 1000-Hz frequency. Following previous studies, tones carried static interaural cues or dynamic cues that peaked at sound onset and diminished to zero at sound offset or vice versa. Although better thresholds were observed in static than dynamic conditions overall, ITD discrimination was especially impaired, regardless of frequency, when cues were not available at sound onset. Results for ILD followed a similar pattern at 1000 Hz; at lower frequencies, ILD thresholds did not differ significantly between dynamic-cue conditions. The results support the "onset" hypothesis of Houtgast and Plomp [(1968). J. Acoust. Soc. Am. 44, 807-812] for ITD discrimination, but not necessarily ILD discrimination, in low-frequency pure tones.

  10. Maps of interaural time difference in the chicken’s brainstem nucleus laminaris

    OpenAIRE

    Köppl, Christine; Carr, Catherine E.

    2008-01-01

    Animals, including humans, use interaural time differences (ITDs) that arise from different sound path lengths to the two ears as a cue of horizontal sound source location. The nature of the neural code for ITD is still controversial. Current models differentiate between two population codes: either a map-like rate-place code of ITD along an array of neurons, consistent with a large body of data in the barn owl, or a population rate code, consistent with data from small mammals. Recently, it ...

  11. Sensitivity to Interaural Time Differences with Combined Cochlear Implant and Acoustic Stimulation

    OpenAIRE

    Francart, Tom; Brokx, Jan; Wouters, Jan

    2008-01-01

    The interaural time difference (ITD) is an important cue to localize sound sources. Sensitivity to ITD was measured in eight users of a cochlear implant (CI) in the one ear and a hearing aid (HA) in the other severely impaired ear. The stimulus consisted of an electric pulse train of 100 pps and an acoustic filtered click train. Just-noticeable differences (JNDs) in ITD were measured using a lateralization paradigm. Four subjects exhibited median JNDs in ITD of 156, 341, 254, and 91 mus; the ...

  12. A Novel Model of Interaural Time Difference Based on Spatial Fourier Analysis

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    ZHONG Xiao-Li; XIE Bo-Sun

    2007-01-01

    Based on the spatial Fourier analysis, a statistical model of the individualized interaural time difference (ITD) is derived from the head-related transfer function database for a Chinese subject. The model reflects the spatial left-right symmetry and front-back asymmetry of ITD. Moreover, by using three anatomical parameters of head and pinna, the model is able to predict individualized ITD in the horizontal plane. Performance of the four subjects outside the database demonstrates that the mean of the total error is less than 20 us, while the lateral performance is inferior to that at other directions.

  13. Functional modelling of interaural time difference discrimination in acoustical and electrical hearing

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    Prokopiou, Andreas; Moncada-Torres, Arturo; Wouters, Jan; Francart, Tom

    2017-08-01

    Objective. Interaural time differences (ITDs) are important for sound source localisation. We present a model to predict the just noticeable differences (JNDs) in ITD discrimination for normal hearing and electric stimulation through a cochlear implant. Approach. We combined periphery models of acoustic and electric stimulation with a novel JND in the ITD estimation stage, which consists of a shuffled cross correlogram and a binary classifier characterisation method. Furthermore, an evaluation framework is presented based on a large behavioural dataset. Main results. The model correctly predicts behavioural observations for unmodulated stimuli (such as pure tones and electric pulse trains) and modulated stimuli for modulation frequencies below 30 Hz. For higher modulation frequencies, the model predicts the observed behavioural trends, but tends to estimate higher ITD sensitivity. Significance. The presented model can be used to investigate the implications of modifying the stimulus waveform on ITD sensitivity, and as such be applied in investigating sound encoding strategies.

  14. Sensitivity to interaural time differences with combined cochlear implant and acoustic stimulation.

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    Francart, Tom; Brokx, Jan; Wouters, Jan

    2009-03-01

    The interaural time difference (ITD) is an important cue to localize sound sources. Sensitivity to ITD was measured in eight users of a cochlear implant (CI) in the one ear and a hearing aid (HA) in the other severely impaired ear. The stimulus consisted of an electric pulse train of 100 pps and an acoustic filtered click train. Just-noticeable differences (JNDs) in ITD were measured using a lateralization paradigm. Four subjects exhibited median JNDs in ITD of 156, 341, 254, and 91 mus; the other subjects could not lateralize the stimuli consistently. Only the subjects who could lateralize had average acoustic hearing thresholds at 1,000 and 2,000 Hz better than 100-dB SPL. The electric signal had to be delayed by 1.5 ms to achieve synchronous stimulation at the auditory nerves.

  15. Representation of interaural time difference in the central nucleus of the barn owl's inferior colliculus.

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    Wagner, H; Takahashi, T; Konishi, M

    1987-10-01

    This paper investigates the role of the central nucleus of the barn owl's inferior colliculus in determination of the sound-source azimuth. The central nucleus contains many neurons that are sensitive to interaural time difference (ITD), the cue for azimuth in the barn owl. The response of these neurons varies in a cyclic manner with the ITD of a tone or noise burst. Response maxima recur at integer multiples of the period of the stimulating tone, or, if the stimulus is noise, at integer multiples of the period corresponding to the neuron's best frequency. Such neurons can signal, by means of their relative spike rate, the phase difference between the sounds reaching the left and right ears. Since an interaural phase difference corresponds to more than one ITD, these neurons represent ITD ambiguously. We call this phenomenon phase ambiguity. The central nucleus is tonotopically organized and its neurons are narrowly tuned to frequency. Neurons in an array perpendicular to isofrequency laminae form a physiological and anatomical unit; only one ITD, the array-specific ITD, activates all neurons in an array at the same relative level. We, therefore, may say that, in the central nucleus, an ITD is conserved in an array of neurons. Array-specific ITDs are mapped and encompass the entire auditory space of the barn owl. Individual space-specific neurons of the external nucleus, which receive inputs from a wide range of frequency channels (Knudsen and Konishi, 1978), are selective for a unique ITD. Space-specific neurons do not show phase ambiguity when stimulated with noise (Takahashi and Konishi, 1986). Space-specific neurons receive inputs from arrays that are selective for the same ITD. The collective response of the neurons in an array may be the basis for the absence of phase ambiguity in space-specific neurons.

  16. Maps of interaural time difference in the chicken's brainstem nucleus laminaris.

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    Köppl, Christine; Carr, Catherine E

    2008-06-01

    Animals, including humans, use interaural time differences (ITDs) that arise from different sound path lengths to the two ears as a cue of horizontal sound source location. The nature of the neural code for ITD is still controversial. Current models differentiate between two population codes: either a map-like rate-place code of ITD along an array of neurons, consistent with a large body of data in the barn owl, or a population rate code, consistent with data from small mammals. Recently, it was proposed that these different codes reflect optimal coding strategies that depend on head size and sound frequency. The chicken makes an excellent test case of this proposal because its physical prerequisites are similar to small mammals, yet it shares a more recent common ancestry with the owl. We show here that, like in the barn owl, the brainstem nucleus laminaris in mature chickens displayed the major features of a place code of ITD. ITD was topographically represented in the maximal responses of neurons along each isofrequency band, covering approximately the contralateral acoustic hemisphere. Furthermore, the represented ITD range appeared to change with frequency, consistent with a pressure gradient receiver mechanism in the avian middle ear. At very low frequencies, below 400 Hz, maximal neural responses were symmetrically distributed around zero ITD and it remained unclear whether there was a topographic representation. These findings do not agree with the above predictions for optimal coding and thus revive the discussion as to what determines the neural coding strategies for ITDs.

  17. Asymmetric excitatory synaptic dynamics underlie interaural time difference processing in the auditory system.

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    Pablo E Jercog

    Full Text Available Low-frequency sound localization depends on the neural computation of interaural time differences (ITD and relies on neurons in the auditory brain stem that integrate synaptic inputs delivered by the ipsi- and contralateral auditory pathways that start at the two ears. The first auditory neurons that respond selectively to ITD are found in the medial superior olivary nucleus (MSO. We identified a new mechanism for ITD coding using a brain slice preparation that preserves the binaural inputs to the MSO. There was an internal latency difference for the two excitatory pathways that would, if left uncompensated, position the ITD response function too far outside the physiological range to be useful for estimating ITD. We demonstrate, and support using a biophysically based computational model, that a bilateral asymmetry in excitatory post-synaptic potential (EPSP slopes provides a robust compensatory delay mechanism due to differential activation of low threshold potassium conductance on these inputs and permits MSO neurons to encode physiological ITDs. We suggest, more generally, that the dependence of spike probability on rate of depolarization, as in these auditory neurons, provides a mechanism for temporal order discrimination between EPSPs.

  18. Interaural intensity and latency difference in the dolphin's auditory system.

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    Popov, V V; Supin AYa

    1991-12-09

    Binaural hearing mechanisms were measured in dolphins (Inia geoffrensis) by recording the auditory nerve evoked response from the body surface. The azimuthal position of a sound source at 10-15 degrees from the longitudinal axis elicited interaural intensity disparity up to 20 dB and interaural latency difference as large as 250 microseconds. The latter was many times greater than the acoustical interaural time delay. This latency difference seems to be caused by the intensity disparity. The latency difference seems to be an effective way of coding of intensity disparity.

  19. Interaural time sensitivity of high-frequency neurons in the inferior colliculus.

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    Yin, T C; Kuwada, S; Sujaku, Y

    1984-11-01

    Recent psychoacoustic experiments have shown that interaural time differences provide adequate cues for lateralizing high-frequency sounds, provided the stimuli are complex and not pure tones. We present here physiological evidence in support of these findings. Neurons of high best frequency in the cat inferior colliculus respond to interaural phase differences of amplitude modulated waveforms, and this response depends upon preservation of phase information of the modulating signal. Interaural phase differences were introduced in two ways: by interaural delays of the entire waveform and by binaural beats in which there was an interaural frequency difference in the modulating waveform. Results obtained with these two methods are similar. Our results show that high-frequency cells can respond to interaural time differences of amplitude modulated signals and that they do so by a sensitivity to interaural phase differences of the modulating waveform.

  20. Effects of Interaural Level and Time Differences on the Externalization of Sound

    DEFF Research Database (Denmark)

    Dau, Torsten; Catic, Jasmina; Santurette, Sébastien;

    - such as wide dynamic range compression - affects the ILDs and thereby potentially reduces the perceived degree of externalization. In the present study, the effect of room reverberation on the spectro-temporal behavior of ILDs was investigated. This was done by analyzing speech played at different distances...... and recorded on a head-andtorso simulator in a standard IEC 268-13 listening room. Next, the effect of ILD fluctuations on the degree of externalization was investigated in a listening experiment with normal-hearing listeners. The experiment was performed in the same standard listening room and a distant...... speech source was simulated via headphones using individual binaural impulse responses. The speech signal was then processed such that the naturally occurring ILD fluctuations were compressed. This manipulation reduced the perceived degree of externalization in the listening experiment, which...

  1. [Auditory-evoked responses to a monaural or a binaural click, recorded from the vertex, as in two temporal derivations; effect of interaural time differences (author's transl)].

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    Botte, M C; Chocholle, R

    1976-01-01

    The auditory-evoked responses have been recorded on 5 subject by vertex, right temporal and left temporal electrodes simultaneously. 30 dB sensation level clicks were used as stimuli; one click was presented only to the right ear, or one click only to the left ear, or one click to the right ear and another click to the left ear with a variable interaural time difference in this latter case (0-150 ms). The N-P amplitude variations and the N and P latency variations have been studied and compared to those observed in the perceived lateralizations of the sound source.

  2. Effects of interaural level differences on the externalization of sound

    DEFF Research Database (Denmark)

    Catic, Jasmina; Santurette, Sébastien; Dau, Torsten

    2012-01-01

    Distant sound sources in our environment are perceived as externalized and are thus properly localized in both direction and distance. This is due to the acoustic filtering by the head, torso, and external ears, which provides frequency-dependent shaping of binaural cues such as interaural level...... differences (ILDs) and interaural time differences (ITDs). In rooms, the sound reaching the two ears is further modified by reverberant energy, which leads to increased fluctuations in short-term ILDs and ITDs. In the present study, the effect of ILD fluctuations on the externalization of sound...... was investigated. A psychoacoustic experiment was performed in a standard IEC 268-13 listening room by normal-hearing listeners. Individual binaural room impulse responses were used to simulate a distant speech source delivered via headphones. The speech signal was then processed such that the naturally occurring...

  3. Binaural model for artificial spatial sound localization based on interaural time delays and movements of the interaural axis.

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    Kneip, Laurent; Baumann, Claude

    2008-11-01

    This paper presents a mathematical model for sound localization in space using two-microphone devices that possess at least two degrees of freedom. It proves a series of theorems and lemmas that are based on time difference of arrival measurements and movements of the interaural axis, forming a powerful instrument for practical robot applications. For instance, it shows that a single determined rotation of the interaural axis is sufficient to exactly yield the azimuth or the elevation of an immobile sound source in the far field, independently of microphone spacing and the speed of sound and hence of the surrounding medium. It proves that at any moment the knowledge of one value determines the magnitude of the other, with the restriction that the sign of the second value is undefined, which means that, depending on the rotation, either the back-front or the up-down ambiguity is kept unsolved. This paper also shows that parallax motion unlocks essential information about the distance and the Cartesian coordinates of the sound source. Shifting the microphone system sideways fixes the distance and the coordinate on the interaural axis. Combining rotation and translation movements completely solves the localization problem. In order to illustrate the efficacy of the model, this paper presents experiments with a low cost robot developer kit during which the azimuth, the elevation, and the distance of continuous sound sources are determined at a precision of 10 degrees and 0.5 m, respectively. Achieving this performance with low power material demonstrates how easily the model can be implemented into any robotic system.

  4. Functional dissociation of transient and sustained fMRI BOLD components in human auditory cortex revealed with a streaming paradigm based on interaural time differences.

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    Schadwinkel, Stefan; Gutschalk, Alexander

    2010-12-01

    A number of physiological studies suggest that feature-selective adaptation is relevant to the pre-processing for auditory streaming, the perceptual separation of overlapping sound sources. Most of these studies are focused on spectral differences between streams, which are considered most important for streaming. However, spatial cues also support streaming, alone or in combination with spectral cues, but physiological studies of spatial cues for streaming remain scarce. Here, we investigate whether the tuning of selective adaptation for interaural time differences (ITD) coincides with the range where streaming perception is observed. FMRI activation that has been shown to adapt depending on the repetition rate was studied with a streaming paradigm where two tones were differently lateralized by ITD. Listeners were presented with five different ΔITD conditions (62.5, 125, 187.5, 343.75, or 687.5 μs) out of an active baseline with no ΔITD during fMRI. The results showed reduced adaptation for conditions with ΔITD ≥ 125 μs, reflected by enhanced sustained BOLD activity. The percentage of streaming perception for these stimuli increased from approximately 20% for ΔITD = 62.5 μs to > 60% for ΔITD = 125 μs. No further sustained BOLD enhancement was observed when the ΔITD was increased beyond ΔITD = 125 μs, whereas the streaming probability continued to increase up to 90% for ΔITD = 687.5 μs. Conversely, the transient BOLD response, at the transition from baseline to ΔITD blocks, increased most prominently as ΔITD was increased from 187.5 to 343.75 μs. These results demonstrate a clear dissociation of transient and sustained components of the BOLD activity in auditory cortex.

  5. Trading of dynamic interaural time and level difference cues and its effect on the auditory motion-onset response measured with electroencephalography.

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    Altmann, Christian F; Ueda, Ryuhei; Bucher, Benoit; Furukawa, Shigeto; Ono, Kentaro; Kashino, Makio; Mima, Tatsuya; Fukuyama, Hidenao

    2017-07-27

    Interaural time (ITD) and level differences (ILD) constitute the two main cues for sound localization in the horizontal plane. Despite extensive research in animal models and humans, the mechanism of how these two cues are integrated into a unified percept is still far from clear. In this study, our aim was to test with human electroencephalography (EEG) whether integration of dynamic ITD and ILD cues is reflected in the so-called motion-onset response (MOR), an evoked potential elicited by moving sound sources. To this end, ITD and ILD trajectories were determined individually by cue trading psychophysics. We then measured EEG while subjects were presented with either static click-trains or click-trains that contained a dynamic portion at the end. The dynamic part was created by combining ITD with ILD either congruently to elicit the percept of a right/leftward moving sound, or incongruently to elicit the percept of a static sound. In two experiments that differed in the method to derive individual dynamic cue trading stimuli, we observed an MOR with at least a change-N1 (cN1) component for both the congruent and incongruent conditions at about 160-190 ms after motion-onset. A significant change-P2 (cP2) component for both the congruent and incongruent ITD/ILD combination was found only in the second experiment peaking at about 250 ms after motion onset. In sum, this study shows that a sound which - by a combination of counter-balanced ITD and ILD cues - induces a static percept can still elicit a motion-onset response, indicative of independent ITD and ILD processing at the level of the MOR - a component that has been proposed to be, at least partly, generated in non-primary auditory cortex. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Response of auditory units in the barn owl's inferior colliculus to continuously varying interaural phase differences.

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    Moiseff, A; Haresign, T

    1992-06-01

    1. We studied the response of single units in the central nucleus of the inferior colliculus (ICc) of the barn owl (Tyto alba) to continuously varying interaural phase differences (IPDs) and static IPDs. Interaural phase was varied in two ways: continuously, by delivering tones to each ear that varied by a few hertz (binaural beat, Fig. 1), and discretely, by delaying in fixed steps the phase of sound delivered to one ear relative to the other (static phase). Static presentations were repeated at several IPDs to characterize interaural phase sensitivity. 2. Units sensitive to IPDs responded to the binaural beat stimulus over a broad range of delta f(Fig. 4). We selected a 3-Hz delta f for most of our comparative measurements on the basis of constraints imposed by our stimulus generation system and because it allowed us to reduce the influence of responses to stimulus onset and offset (Fig. 3A). 3. Characteristic interaural time or phase sensitivity obtained by the use of the binaural beat stimulus were comparable with those obtained by the use of the static technique (Fig. 5; r2 = 0.93, Fig. 6). 4. The binaural beat stimulus facilitated the measurement of characteristic delay (CD) and characteristic phase (CP) of auditory units. We demonstrated that units in the owl's inferior colliculus (IC) include those that are maximally excited by specific IPDs (CP = 0 or 1.0) as well as those that are maximally suppressed by specific IPDs (CP = 0.5; Figs. 7 and 8). 5. The selectivity of units sensitive to IPD or interaural time difference (ITD) were weakly influenced by interaural intensity difference (IID).(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Interaural difference values of vestibular evoked myogenic.

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    Marziyeh Moallemi

    2015-01-01

    Full Text Available Migraine is a neurologic disease, which often is associated with a unilateral headache. Vestibular abnormalities are common in migraine. Vestibular evoked myogenic potentials (VEMPs assess otolith function in particular functional integrity of the saccule and the inferior vestibular nerve. We used VEMP to evaluate if the migraine headache can affect VEMP asymmetry parameters. A total of 25 patients with migraine (22 females and 3 males who were diagnosed according to the criteria of IHS-1988 were enrolled in this cross-sectional study. Control group consisted of 26 healthy participants (18 female and 8 male, without neurotological symptoms and history of migraine. The short tone burst (95 dB nHL, 500 Hz was presented to ears. VEMP was recorded with surface electromyography over the contracted ipsilateral sternocleidomastoid (SCM muscle. Although current results showed that the amplitude ratio is greater in migraine patients than normal group, there was no statistical difference between two groups in mean asymmetry parameters of VEMP. Asymmetry measurements in vestibular evoked myogenic potentials probably are not indicators of unilateral deficient in saccular pathways of migraine patients.

  8. Regularly firing neurons in the inferior colliculus have a weak interaural intensity difference sensitivity.

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    Nasimi, Ali; Rees, Adrian

    2010-12-01

    The spike discharge regularity may be important in the processing of information in the auditory pathway. It has already been shown that many cells in the central nucleus of the inferior colliculus fire regularly in response to monaural stimulation by the best frequency tones. The aim of this study was to find how the regularity of units was affected by adding ipsilateral tone, and how interaural intensity difference sensitivity is related to regularity. Single unit recordings were performed from 66 units in the inferior colliculus of the anaesthetized guinea pig in response to the best frequency tone. Regularity of firing was measured by calculating the coefficient of variation as a function of time of a unit's response. There was a positive correlation between coefficient of variation and interaural intensity difference sensitivity, indicating that highly regular units had very weak and irregular units had strong interaural intensity difference sensitivity responses. Three effects of binaural interaction on the sustained regularity were observed: constant coefficient of variation despite change in rate (66% of the units), negative (20%) and positive (13%) rate-CV relationships. A negative rate-coefficient of variation relationship was the dominant pattern of binaural interaction on the onset regularity.

  9. Neuronal specializations for the processing of interaural difference cues in the chick

    Directory of Open Access Journals (Sweden)

    Harunori eOhmori

    2014-05-01

    Full Text Available Sound information is encoded as a series of spikes of the auditory nerve fibers (ANFs, and then transmitted to the brainstem auditory nuclei. Features such as timing and level are extracted from ANFs activity and further processed as the interaural time difference (ITD and the interaural level difference (ILD, respectively. These two interaural difference cues are used for sound source localization by behaving animals. Both cues depend on the head size of animals and are extremely small, requiring specialized neural properties in order to process these cues with precision. Moreover, the sound level and timing cues are not processed independently from one another. Neurons in the nucleus angularis (NA are specialized for coding sound level information in birds and the ILD is processed in the posterior part of the dorsal lateral lemniscus nucleus (LLDp. Processing of ILD is affected by the phase difference of binaural sound. Temporal features of sound are encoded in the pathway starting in nucleus magnocellularis (NM, and ITD is processed in the nucleus laminaris (NL. In this pathway a variety of specializations are found in synapse morphology, neuronal excitability, distribution of ion channels and receptors along the tonotopic axis, which reduces spike timing fluctuation in the ANFs-NM synapse, and imparts precise and stable ITD processing to the NL. Moreover, the contrast of ITD processing in NL is enhanced over a wide range of sound level through the activity of GABAergic inhibitory systems from both the superior olivary nucleus (SON and local inhibitory neurons that follow monosynaptic to NM activity.

  10. Reproduction of nearby sources by imposing true interaural differences on a sound field control approach

    DEFF Research Database (Denmark)

    Badajoz, Javier; Chang, Ji-ho; Agerkvist, Finn T.

    2015-01-01

    In anechoic conditions, the Interaural Level Difference (ILD) is the most significant auditory cue to judge the distance to a sound source located within 1 m of the listener's head. This is due to the unique characteristics of a point source in its near field, which result in exceptionally high, ...

  11. Direction-dependent spectral sensitivity and interaural spectral difference in a dolphin: evoked potential study.

    Science.gov (United States)

    Supin AYa; Popov, V V

    1993-06-01

    Sensitivity and interaural intensity difference (IID) dependence on sound frequency and direction was measured in an Amazon river dolphin Inia geoffrensis by recording the auditory nerve evoked response from the body surface. The maximal sensitivity in the horizontal plane was found when the sound direction was 5 degrees to 10 degrees ipsilateral to the recorded ear; the direction dependence of sensitivity was more pronounced at higher frequencies than at lower ones. The IID reached its peak at small azimuthal angles (7.5 degrees to 15 degrees) and higher sound frequencies (100 kHz), or at large azimuthal angles (30 degrees to 45 degrees) and lower sound frequencies (20 to 30 kHz). Each sound direction featured its specific pattern of spectral sensitivity and of interaural spectral difference. The interaural spectral difference fluctuated within a range of more than 20 dB depending on sound direction. The data indicate that interaural intensity as well as spectral difference may be cues for binaural localization of sound direction by dolphins.

  12. Electrophysiological study of interaural sound intensity difference in the dolphin Inia geoffrensis.

    Science.gov (United States)

    Supin AYa; Popov, V V; Klishin, V O

    1991-09-15

    A wave observed in the auditory brainstem responses (ABR), sensitive to the side of sound presentation, is described in a dolphin (Inia geoffrensis). Dependence of the wave threshold on location of the sound source showed that the interaural intensity difference was more than 20 dB.

  13. Acoustic and perceptual effects of magnifying interaural difference cues in a simulated "binaural" hearing aid.

    Science.gov (United States)

    de Taillez, Tobias; Grimm, Giso; Kollmeier, Birger; Neher, Tobias

    2017-04-10

    To investigate the influence of an algorithm designed to enhance or magnify interaural difference cues on speech signals in noisy, spatially complex conditions using both technical and perceptual measurements. To also investigate the combination of interaural magnification (IM), monaural microphone directionality (DIR), and binaural coherence-based noise reduction (BC). Speech-in-noise stimuli were generated using virtual acoustics. A computational model of binaural hearing was used to analyse the spatial effects of IM. Predicted speech quality changes and signal-to-noise-ratio (SNR) improvements were also considered. Additionally, a listening test was carried out to assess speech intelligibility and quality. Listeners aged 65-79 years with and without sensorineural hearing loss (N = 10 each). IM increased the horizontal separation of concurrent directional sound sources without introducing any major artefacts. In situations with diffuse noise, however, the interaural difference cues were distorted. Preprocessing the binaural input signals with DIR reduced distortion. IM influenced neither speech intelligibility nor speech quality. The IM algorithm tested here failed to improve speech perception in noise, probably because of the dispersion and inconsistent magnification of interaural difference cues in complex environments.

  14. Trading of interaural differences in high-rate Gabor click trains

    Science.gov (United States)

    Stecker, G. Christopher

    2010-01-01

    In this study, combinations of interaraural time differences (ITD) and interaural level differences (ILD) were applied to trains of 4000 Hz Gabor clicks (Gaussian-filtered impulses) and presented to listeners over headphones. ITD / ILD equivalence functions, or “trading ratios” (TR) were estimated using two different procedures: a “closed-loop” procedure in which subjects adjusted (via head-turn) the ILD of a target click train to counteract the effects of an imposed ITD, and an “open-loop” procedure in which subjects indicated (also via head-turn) the lateral position of click trains containing independent combinations of ITD and ILD. For both tasks, TR values increasingly favored ILD over ITD as inter-click interval (ICI) decreased from 10 to 2 ms. Subsequent analysis confirmed that this change reflected a loss of sensitivity to envelope ITD at short ICI rather than a gain in sensitivity to ILD, consistent with prior studies demonstrating rate-limited processing of ongoing envelope ITD. Significant intersubject differences in the data included two subjects whose TR values obtained under both procedures were consistently lower (greater influence of ITD) than other subjects', and did not vary with ICI. Such differences suggest that multiple mechanisms of ITD/ILD combination may be utilized to varying degrees by individual listeners. By at least one of those mechanisms, ITD sensitivity (but not ILD sensitivity) is limited to low modulation rates. PMID:20547218

  15. Transformation of binaural response properties in the ascending auditory pathway: influence of time-varying interaural phase disparity.

    Science.gov (United States)

    Spitzer, M W; Semple, M N

    1998-12-01

    Transformation of binaural response properties in the ascending auditory pathway: influence of time-varying interaural phase disparity. J. Neurophysiol. 80: 3062-3076, 1998. Previous studies demonstrated that tuning of inferior colliculus (IC) neurons to interaural phase disparity (IPD) is often profoundly influenced by temporal variation of IPD, which simulates the binaural cue produced by a moving sound source. To determine whether sensitivity to simulated motion arises in IC or at an earlier stage of binaural processing we compared responses in IC with those of two major IPD-sensitive neuronal classes in the superior olivary complex (SOC), neurons whose discharges were phase locked (PL) to tonal stimuli and those that were nonphase locked (NPL). Time-varying IPD stimuli consisted of binaural beats, generated by presenting tones of slightly different frequencies to the two ears, and interaural phase modulation (IPM), generated by presenting a pure tone to one ear and a phase modulated tone to the other. IC neurons and NPL-SOC neurons were more sharply tuned to time-varying than to static IPD, whereas PL-SOC neurons were essentially uninfluenced by the mode of stimulus presentation. Preferred IPD was generally similar in responses to static and time-varying IPD for all unit populations. A few IC neurons were highly influenced by the direction and rate of simulated motion, but the major effect for most IC neurons and all SOC neurons was a linear shift of preferred IPD at high rates-attributable to response latency. Most IC and NPL-SOC neurons were strongly influenced by IPM stimuli simulating motion through restricted ranges of azimuth; simulated motion through partially overlapping azimuthal ranges elicited discharge profiles that were highly discontiguous, indicating that the response associated with a particular IPD is dependent on preceding portions of the stimulus. In contrast, PL-SOC responses tracked instantaneous IPD throughout the trajectory of simulated

  16. Neural map of interaural phase difference in the owl's brainstem.

    OpenAIRE

    Sullivan, W. E.; Konishi, M

    1986-01-01

    Neurons of the barn owl's (Tyto alba) nucleus laminaris, the first site of binaural convergence, respond in a phase-locked fashion to a tone delivered to either ear. It may take longer to elicit phase-locked spikes from one ear than from the other. This disparity in delay differs from neuron to neuron and is independent of tonal frequency. In binaural stimulation, neurons respond best when sound in one ear leads that in the other by an amount equal to their delay disparities but opposite in s...

  17. Interaural level difference-dependent gain control and synaptic scaling underlying binaural computation.

    Science.gov (United States)

    Xiong, Xiaorui R; Liang, Feixue; Li, Haifu; Mesik, Lukas; Zhang, Ke K; Polley, Daniel B; Tao, Huizhong W; Xiao, Zhongju; Zhang, Li I

    2013-08-21

    Binaural integration in the central nucleus of inferior colliculus (ICC) plays a critical role in sound localization. However, its arithmetic nature and underlying synaptic mechanisms remain unclear. Here, we showed in mouse ICC neurons that the contralateral dominance is created by a "push-pull"-like mechanism, with contralaterally dominant excitation and more bilaterally balanced inhibition. Importantly, binaural spiking response is generated apparently from an ipsilaterally mediated scaling of contralateral response, leaving frequency tuning unchanged. This scaling effect is attributed to a divisive attenuation of contralaterally evoked synaptic excitation onto ICC neurons with their inhibition largely unaffected. Thus, a gain control mediates the linear transformation from monaural to binaural spike responses. The gain value is modulated by interaural level difference (ILD) primarily through scaling excitation to different levels. The ILD-dependent synaptic scaling and gain adjustment allow ICC neurons to dynamically encode interaural sound localization cues while maintaining an invariant representation of other independent sound attributes. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Commissural connections mediate inhibition for the computation of interaural level difference in the barn owl.

    Science.gov (United States)

    Takahashi, T T; Keller, C H

    1992-02-01

    In the barn owl (Tyto alba), the posterior nucleus of the ventral lateral lemniscus (VLVp) is the first site of binaural convergence in the pathway that processes interaural level difference (ILD), an important sound-localization cue. The neurons of VLVp are sensitive to ILD because of an excitatory input from the contralateral ear and an inhibitory input from the ipsilateral ear. A previously described projection from the contralateral cochlear nucleus, can account for the excitation. The present study addresses the source of the inhibitory input. We demonstrate with standard axonal transport methods that the left and right VLVps are interconnected via fibers of the commissure of Probst. We further show that the anesthetization of one VLVp renders ineffective the inhibition that is normally evoked by stimulation of the ipsilateral ear. Thus, one cochlear nucleus (driven by the ipsilateral ear) appears to provide inhibition to the ipsilateral VLVp by exciting commissurally-projecting inhibitory neurons in the contralateral VLVp.

  19. Blind people are more sensitive than sighted people to binaural sound-location cues, particularly inter-aural level differences.

    Science.gov (United States)

    Nilsson, Mats E; Schenkman, Bo N

    2016-02-01

    Blind people use auditory information to locate sound sources and sound-reflecting objects (echolocation). Sound source localization benefits from the hearing system's ability to suppress distracting sound reflections, whereas echolocation would benefit from "unsuppressing" these reflections. To clarify how these potentially conflicting aspects of spatial hearing interact in blind versus sighted listeners, we measured discrimination thresholds for two binaural location cues: inter-aural level differences (ILDs) and inter-aural time differences (ITDs). The ILDs or ITDs were present in single clicks, in the leading component of click pairs, or in the lagging component of click pairs, exploiting processes related to both sound source localization and echolocation. We tested 23 blind (mean age = 54 y), 23 sighted-age-matched (mean age = 54 y), and 42 sighted-young (mean age = 26 y) listeners. The results suggested greater ILD sensitivity for blind than for sighted listeners. The blind group's superiority was particularly evident for ILD-lag-click discrimination, suggesting not only enhanced ILD sensitivity in general but also increased ability to unsuppress lagging clicks. This may be related to the blind person's experience of localizing reflected sounds, for which ILDs may be more efficient than ITDs. On the ITD-discrimination tasks, the blind listeners performed better than the sighted age-matched listeners, but not better than the sighted young listeners. ITD sensitivity declines with age, and the equal performance of the blind listeners compared to a group of substantially younger listeners is consistent with the notion that blind people's experience may offset age-related decline in ITD sensitivity. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  20. Linear processing of interaural level difference underlies spatial tuning in the nucleus of the brachium of the inferior colliculus.

    Science.gov (United States)

    Slee, Sean J; Young, Eric D

    2013-02-27

    The spatial location of sounds is an important aspect of auditory perception, but the ways in which space is represented are not fully understood. No space map has been found within the primary auditory pathway. However, a space map has been found in the nucleus of the brachium of the inferior colliculus (BIN), which provides a major auditory projection to the superior colliculus. We measured the spectral processing underlying auditory spatial tuning in the BIN of unanesthetized marmoset monkeys. Because neurons in the BIN respond poorly to tones and are broadly tuned, we used a broadband stimulus with random spectral shapes (RSSs) from which both spatial receptive fields and frequency sensitivity can be derived. Responses to virtual space (VS) stimuli, based on the animal's own ear acoustics, were compared with the predictions of a weight-function model of responses to the RSS stimuli. First-order (linear) weight functions had broad spectral tuning (approximately three octaves) and were excitatory in the contralateral ear, inhibitory in the ipsilateral ear, and biased toward high frequencies. Responses to interaural time differences and spectral cues were relatively weak. In cross-validation tests, the first-order RSS model accurately predicted the measured VS tuning curves in the majority of neurons, but was inaccurate in 25% of neurons. In some cases, second-order weighting functions led to significant improvements. Finally, we found a significant correlation between the degree of binaural weight asymmetry and the best azimuth. Overall, the results suggest that linear processing of interaural level difference underlies spatial tuning in the BIN.

  1. Synaptic mechanisms underlying interaural level difference selectivity in rat auditory cortex

    Science.gov (United States)

    Kyweriga, Michael; Stewart, Whitney; Cahill, Carolyn

    2014-01-01

    The interaural level difference (ILD) is a sound localization cue that is extensively processed in the auditory brain stem and midbrain and is also represented in the auditory cortex. Here, we asked whether neurons in the auditory cortex passively inherit their ILD tuning from subcortical sources or whether their spiking preferences were actively shaped by local inhibition. If inherited, the ILD selectivity of spiking output should match that of excitatory synaptic input. If shaped by local inhibition, by contrast, excitation should be more broadly tuned than spiking output with inhibition suppressing spiking for nonpreferred stimuli. To distinguish between these two processing strategies, we compared spiking responses with excitation and inhibition in the same neurons across a range of ILDs and average binaural sound levels. We found that cells preferring contralateral ILDs (often called EI cells) followed the inheritance strategy. In contrast, cells that were unresponsive to monaural sounds but responded predominantly to near-zero ILDs (PB cells) instead showed evidence of the local processing strategy. These PB cells received excitatory inputs that were similar to those received by the EI cells. However, contralateral monaural sounds and ILDs >0 dB elicited strong inhibition, quenching the spiking output. These results suggest that in the rat auditory cortex, EI cells do not utilize inhibition to shape ILD sensitivity, whereas PB cells do. We conclude that an auditory cortical circuit computes sensitivity for near-zero ILDs. PMID:25185807

  2. Representation of dynamic interaural phase difference in auditory cortex of awake rhesus macaques.

    Science.gov (United States)

    Scott, Brian H; Malone, Brian J; Semple, Malcolm N

    2009-04-01

    Neurons in auditory cortex of awake primates are selective for the spatial location of a sound source, yet the neural representation of the binaural cues that underlie this tuning remains undefined. We examined this representation in 283 single neurons across the low-frequency auditory core in alert macaques, trained to discriminate binaural cues for sound azimuth. In response to binaural beat stimuli, which mimic acoustic motion by modulating the relative phase of a tone at the two ears, these neurons robustly modulate their discharge rate in response to this directional cue. In accordance with prior studies, the preferred interaural phase difference (IPD) of these neurons typically corresponds to azimuthal locations contralateral to the recorded hemisphere. Whereas binaural beats evoke only transient discharges in anesthetized cortex, neurons in awake cortex respond throughout the IPD cycle. In this regard, responses are consistent with observations at earlier stations of the auditory pathway. Discharge rate is a band-pass function of the frequency of IPD modulation in most neurons (73%), but both discharge rate and temporal synchrony are independent of the direction of phase modulation. When subjected to a receiver operator characteristic analysis, the responses of individual neurons are insufficient to account for the perceptual acuity of these macaques in an IPD discrimination task, suggesting the need for neural pooling at the cortical level.

  3. Effect of background noise on neuronal coding of interaural level difference cues in rat inferior colliculus

    Science.gov (United States)

    Mokri, Yasamin; Worland, Kate; Ford, Mark; Rajan, Ramesh

    2015-01-01

    Humans can accurately localize sounds even in unfavourable signal-to-noise conditions. To investigate the neural mechanisms underlying this, we studied the effect of background wide-band noise on neural sensitivity to variations in interaural level difference (ILD), the predominant cue for sound localization in azimuth for high-frequency sounds, at the characteristic frequency of cells in rat inferior colliculus (IC). Binaural noise at high levels generally resulted in suppression of responses (55.8%), but at lower levels resulted in enhancement (34.8%) as well as suppression (30.3%). When recording conditions permitted, we then examined if any binaural noise effects were related to selective noise effects at each of the two ears, which we interpreted in light of well-known differences in input type (excitation and inhibition) from each ear shaping particular forms of ILD sensitivity in the IC. At high signal-to-noise ratios (SNR), in most ILD functions (41%), the effect of background noise appeared to be due to effects on inputs from both ears, while for a large percentage (35.8%) appeared to be accounted for by effects on excitatory input. However, as SNR decreased, change in excitation became the dominant contributor to the change due to binaural background noise (63.6%). These novel findings shed light on the IC neural mechanisms for sound localization in the presence of continuous background noise. They also suggest that some effects of background noise on encoding of sound location reported to be emergent in upstream auditory areas can also be observed at the level of the midbrain. PMID:25865218

  4. Effect of background noise on neuronal coding of interaural level difference cues in rat inferior colliculus.

    Science.gov (United States)

    Mokri, Yasamin; Worland, Kate; Ford, Mark; Rajan, Ramesh

    2015-07-01

    Humans can accurately localize sounds even in unfavourable signal-to-noise conditions. To investigate the neural mechanisms underlying this, we studied the effect of background wide-band noise on neural sensitivity to variations in interaural level difference (ILD), the predominant cue for sound localization in azimuth for high-frequency sounds, at the characteristic frequency of cells in rat inferior colliculus (IC). Binaural noise at high levels generally resulted in suppression of responses (55.8%), but at lower levels resulted in enhancement (34.8%) as well as suppression (30.3%). When recording conditions permitted, we then examined if any binaural noise effects were related to selective noise effects at each of the two ears, which we interpreted in light of well-known differences in input type (excitation and inhibition) from each ear shaping particular forms of ILD sensitivity in the IC. At high signal-to-noise ratios (SNR), in most ILD functions (41%), the effect of background noise appeared to be due to effects on inputs from both ears, while for a large percentage (35.8%) appeared to be accounted for by effects on excitatory input. However, as SNR decreased, change in excitation became the dominant contributor to the change due to binaural background noise (63.6%). These novel findings shed light on the IC neural mechanisms for sound localization in the presence of continuous background noise. They also suggest that some effects of background noise on encoding of sound location reported to be emergent in upstream auditory areas can also be observed at the level of the midbrain.

  5. Interaural phase difference modulates the neural activity in the nucleus angularis and improves the processing of level difference cue in the lateral lemniscal nucleus in the chicken.

    Science.gov (United States)

    Sato, Tatsuo; Fukui, Iwao; Ohmori, Harunori

    2010-02-01

    We investigated the chicken auditory system to understand how an interaural level difference (ILD) is processed. Sound intensity is extracted in the nucleus angularis (NA) and an ILD is processed in the dorsal lateral lemniscal nucleus (LLD). We found that the neural activity in these nuclei is affected by the interaural phase difference (IPD). Activity in the NA was suppressed by strong contralateral sound when binaural stimuli were presented in-phase, but the activity was enhanced by out-of-phase stimuli. These IPD dependent suppression or enhancement probably occurs through acoustic interference across the interaural canal connecting the middle ears of the two sides. The LLD neurons were excited by contralateral sound and inhibited by ipsilateral sound, reflecting excitation by the contralateral NA and inhibition from the ipsilateral NA, probably through the contralateral LLD as in the barn owl. The LLD unit activity encoded an ILD and was strongly modulated by the IPD. We propose a simple model to explain the interaural coupling effects and IPD modulation of LLD activity, and conclude that the modulation of neuronal activity by IPD may improve ILD processing and the direction sensitivity of LLD neurons to the contralateral ear, compensating for the small ILD cues.

  6. The across frequency independence of equalization of interaural time delay in the equalization-cancellation model of binaural unmasking

    Science.gov (United States)

    Akeroyd, Michael A.

    2004-08-01

    The equalization stage in the equalization-cancellation model of binaural unmasking compensates for the interaural time delay (ITD) of a masking noise by introducing an opposite, internal delay [N. I. Durlach, in Foundations of Modern Auditory Theory, Vol. II., edited by J. V. Tobias (Academic, New York, 1972)]. Culling and Summerfield [J. Acoust. Soc. Am. 98, 785-797 (1995)] developed a multi-channel version of this model in which equalization was ``free'' to use the optimal delay in each channel. Two experiments were conducted to test if equalization was indeed free or if it was ``restricted'' to the same delay in all channels. One experiment measured binaural detection thresholds, using an adaptive procedure, for 1-, 5-, or 17-component tones against a broadband masking noise, in three binaural configurations (N0S180, N180S0, and N90S270). The thresholds for the 1-component stimuli were used to normalize the levels of each of the 5- and 17-component stimuli so that they were equally detectable. If equalization was restricted, then, for the 5- and 17-component stimuli, the N90S270 and N180S0 configurations would yield a greater threshold than the N0S180 configurations. No such difference was found. A subsequent experiment measured binaural detection thresholds, via psychometric functions, for a 2-component complex tone in the same three binaural configurations. Again, no differential effect of configuration was observed. An analytic model of the detection of a complex tone showed that the results were more consistent with free equalization than restricted equalization, although the size of the differences was found to depend on the shape of the psychometric function for detection.

  7. The Preferred Initial Time Delay Gap and Inter-Aural Cross Correlation for a Javanese Gamelan Performance Hall

    Science.gov (United States)

    Sarwono, J.; Lam, Y. W.

    2002-11-01

    This paper discusses the application of a method based on human subjective preference to the acoustic design of a Javanese gamelan performance hall. Some important distinctions between Javanese gamelan ensembles and Western classical orchestra are the tuning system, orchestral blending process, and technique of playing. The results of subjective preference test using the rank order method showed that the subjects preferred 24·25 ms for the initial time delay gap ( ITDG) and the smallest value of the inter-aural cross-correlation ( IACC). The preferred ITDG agree with the ITDG from the room response measured in a traditional pendopo in Indonesia, which is not a common concert hall but an open-sided hall. However, the preferred IACC is not in agreement with the measured ITDG in the pendopo .

  8. Room Volume Estimation Based on Ambiguity of Short-Term Interaural Phase Differences Using Humanoid Robot Head

    Directory of Open Access Journals (Sweden)

    Ryuichi Shimoyama

    2016-07-01

    Full Text Available Humans can recognize approximate room size using only binaural audition. However, sound reverberation is not negligible in most environments. The reverberation causes temporal fluctuations in the short-term interaural phase differences (IPDs of sound pressure. This study proposes a novel method for a binaural humanoid robot head to estimate room volume. The method is based on the statistical properties of the short-term IPDs of sound pressure. The humanoid robot turns its head toward a sound source, recognizes the sound source, and then estimates the ego-centric distance by its stereovision. By interpolating the relations between room volume, average standard deviation, and ego-centric distance experimentally obtained for various rooms in a prepared database, the room volume was estimated by the binaural audition of the robot from the average standard deviation of the short-term IPDs at the estimated distance.

  9. Binaural interaction in low-frequency neurons in inferior colliculus of the cat. II. Effects of changing rate and direction of interaural phase.

    Science.gov (United States)

    Yin, T C; Kuwada, S

    1983-10-01

    We used the binaural beat stimulus to study the interaural phase sensitivity of inferior colliculus (IC) neurons in the cat. The binaural beat, produced by delivering tones of slightly different frequencies to the two ears, generates continuous and graded changes in interaural phase. Over 90% of the cells that exhibit a sensitivity to changes in the interaural delay also show a sensitivity to interaural phase disparities with the binaural beat. Cells respond with a burst of impulses with each complete cycle of the beat frequency. The period histogram obtained by binning the poststimulus time histogram on the beat frequency gives a measure of the interaural phase sensitivity of the cell. In general, there is good correspondence in the shapes of the period histograms generated from binaural beats and the interaural phase curves derived from interaural delays and in the mean interaural phase angle calculated from them. The magnitude of the beat frequency determines the rate of change of interaural phase and the sign determines the direction of phase change. While most cells respond in a phase-locked manner up to beat frequencies of 10 Hz, there are some cells tht will phase lock up to 80 Hz. Beat frequency and mean interaural phase angle are linearly related for most cells. Most cells respond equally in the two directions of phase change and with different rates of change, at least up to 10 Hz. However, some IC cells exhibit marked sensitivity to the speed of phase change, either responding more vigorously at low beat frequencies or at high beat frequencies. In addition, other cells demonstrate a clear directional sensitivity. The cells that show sensitivity to the direction and speed of phase changes would be expected to demonstrate a sensitivity to moving sound sources in the free field. Changes in the mean interaural phase of the binaural beat period histograms are used to determine the effects of changes in average and interaural intensity on the phase sensitivity

  10. Cochlear efferent feedback balances interaural sensitivity

    OpenAIRE

    2006-01-01

    Neurons in the lateral superior olive (LSO) compute sound location based on differences in interaural intensity, coded in ascending signals from the two cochleas. Unilateral destruction of the neuronal feedback from the LSO to the cochlea, the lateral olivocochlear efferents, disrupted the normal interaural correlation in response amplitudes to sounds of equal intensity. Thus, lateral olivocochlear feedback maintains the binaural balance in neural excitability required for accurate localizati...

  11. Translational Vestibulo-Ocular Reflex and Motion Perception During Interaural Linear Acceleration: Comparison of Different Motion Paradigms

    Science.gov (United States)

    Beaton, K. H.; Holly, J. E.; Clement, G. R.; Wood, S. J.

    2011-01-01

    The neural mechanisms to resolve ambiguous tilt-translation motion have been hypothesized to be different for motion perception and eye movements. Previous studies have demonstrated differences in ocular and perceptual responses using a variety of motion paradigms, including Off-Vertical Axis Rotation (OVAR), Variable Radius Centrifugation (VRC), translation along a linear track, and tilt about an Earth-horizontal axis. While the linear acceleration across these motion paradigms is presumably equivalent, there are important differences in semicircular canal cues. The purpose of this study was to compare translation motion perception and horizontal slow phase velocity to quantify consistencies, or lack thereof, across four different motion paradigms. Twelve healthy subjects were exposed to sinusoidal interaural linear acceleration between 0.01 and 0.6 Hz at 1.7 m/s/s (equivalent to 10 tilt) using OVAR, VRC, roll tilt, and lateral translation. During each trial, subjects verbally reported the amount of perceived peak-to-peak lateral translation and indicated the direction of motion with a joystick. Binocular eye movements were recorded using video-oculography. In general, the gain of translation perception (ratio of reported linear displacement to equivalent linear stimulus displacement) increased with stimulus frequency, while the phase did not significantly vary. However, translation perception was more pronounced during both VRC and lateral translation involving actual translation, whereas perceptions were less consistent and more variable during OVAR and roll tilt which did not involve actual translation. For each motion paradigm, horizontal eye movements were negligible at low frequencies and showed phase lead relative to the linear stimulus. At higher frequencies, the gain of the eye movements increased and became more inphase with the acceleration stimulus. While these results are consistent with the hypothesis that the neural computational strategies for

  12. Responses of Neurons in the Marmoset Primary Auditory Cortex to Interaural Level Differences: Comparison of Pure Tones and Vocalizations.

    Directory of Open Access Journals (Sweden)

    Leo L Lui

    2015-04-01

    Full Text Available Interaural level differences (ILDs are the dominant cue for localizing the sources of high frequency sounds that differ in azimuth. Neurons in the primary auditory cortex (A1 respond differentially to ILDs of simple stimuli such as tones and noise bands, but the extent to which this applies to complex natural sounds, such as vocalizations, is not known. In sufentanil/N2O anaesthetized marmosets, we compared the responses of 76 A1 neurons to three vocalizations (Ock, Tsik and Twitter and pure tones at cells’ characteristic frequency. Each stimulus was presented with ILDs ranging from 20dB favouring the contralateral ear to 20dB favouring the ipsilateral ear to cover most of the frontal azimuthal space. The response to each stimulus was tested at three average binaural levels (ABLs. Most neurons were sensitive to ILDs of vocalizations and pure tones. For all stimuli, the majority of cells had monotonic ILD sensitivity functions favouring the contralateral ear, but we also observed ILD sensitivity functions that peaked near the midline and functions favouring the ipsilateral ear. Representation of ILD in A1 was better for pure tones and the Ock vocalization in comparison to the Tsik and Twitter calls; this was reflected by higher discrimination indices and greater modulation ranges. ILD sensitivity was heavily dependent on ABL: changes in ABL by ±20 dB SPL from the optimal level for ILD sensitivity led to significant decreases in ILD sensitivity for all stimuli, although ILD sensitivity to pure tones and Ock calls was most robust to such ABL changes. Our results demonstrate differences in ILD coding for pure tones and vocalizations, showing that ILD sensitivity in A1 to complex sounds cannot be simply extrapolated from that to pure tones. They also show A1 neurons do not show level-invariant representation of ILD, suggesting that such a representation of auditory space is likely to require population coding, and further processing at subsequent

  13. Sensitivity to a break in interaural correlation is co-modulated by intensity level and interaural delay.

    Science.gov (United States)

    Kong, Lingzhi; Xie, Zilong; Lu, Lingxi; Wu, Xihong; Li, Liang

    2012-08-01

    This study investigated whether sound intensity affects listeners' sensitivity to a break in interaural correlation (BIC) embedded in wideband noise at different interaural delays. The results show that the detection duration threshold remained stable at the intensity between 60 and 70 dB SPL, but increased in accelerating fashion as the intensity decreased toward 40 dB SPL. Moreover, the threshold elevated linearly as the interaural delay increased from 0 to 4 ms, and the elevation slope became larger as the intensity decreased from 50 to 40 dB SPL. Thus, detecting the BIC is co-modulated by both intensity and interaural delay.

  14. The effect of interaural-level-difference fluctuations on the externalization of sound

    DEFF Research Database (Denmark)

    Catic, Jasmina; Santurette, Sébastien; Buchholz, Jörg M.

    2013-01-01

    in a standard listening room. Next, the effect of ILD fluctuations on the degree of externalization was investigated in a psychoacoustic experiment performed in the same listening room. Individual binaural impulse responses were used to simulate a distant sound source delivered via headphones. The ILDs were......Real-world sound sources are usually perceived as externalized and thus properly localized in both direction and distance. This is largely due to (1) the acoustic filtering by the head, torso, and pinna, resulting in modifications of the signal spectrum and thereby a frequency-dependent shaping...... with the analysis of short-term ILDs at different distances showing that a decreased distance to the sound source also reduced the ILD fluctuations. © 2013 Acoustical Society of America....

  15. Early monaural occlusion alters the neural map of interaural level differences in the inferior colliculus of the barn owl.

    Science.gov (United States)

    Mogdans, J; Knudsen, E I

    1993-08-13

    Monaural occlusion during early life causes adaptive changes in the tuning of units in the owl's optic tectum to interaural level differences (ILD) that tend to align the auditory with the visual map of space. We investigated whether these changes could be due to experience-dependent plasticity occurring in the auditory pathway prior to the optic tectum. Units were recorded in the external nucleus of the inferior colliculus (ICx), which is a major source of auditory input to the optic tectum. The tuning of ICx units to ILD was measured in normal barn owls and in barn owls raised with one ear occluded. ILD tuning at each recording site was measured with dichotic noise bursts, presented at a constant average binaural level, 20 dB above threshold. The best ILD at each site was defined as the midpoint of the range of ILD values which elicited more than 50% of the maximum response. A physiological map of ILD was found in the ICx of normal owls: best ILDs changed systematically from right-ear-greater to left-ear-greater as the electrode progressed from dorsal to ventral. Best ILDs ranged from 13 dB right-ear-greater to 15 dB left-ear-greater and progressed at an average rate of 12 dB/mm. The representations of ILD were similar on both sides of the brain. In the ICx of owls raised with one ear occluded, the map of ILD was shifted in the adaptive direction: ILD tuning was shifted towards values favoring the non-occluded ear (the direction that would restore a normal space map). The average magnitude of the shift was on the order of 8-10 dB in each of 4 owls. In one owl, the mean shift in ILD tuning was almost identical on both sides of the brain. In another owl, the mean shift was much larger on the side ipsilateral to the occlusion than on the contralateral side. In both cases, the mean shifts measured in each ICx were comparable to the mean shifts measured in the optic tectum on the same sides of the brain. Thus, the adjustments in ILD tuning that have been observed in

  16. On the use of click-evoked electric brainstem responses in audiological diagnosis. IV. Interaural latency differences (wave V) in cochlear hearing loss.

    Science.gov (United States)

    Rosenhamer, H J; Lindström, B; Lundborg, T

    1981-01-01

    Interaural latency differences (ILDs) of wave V of the brainstem electric response (BSER) were studied (1) in 20 normal-hearing subjects at 90, 80, 60 and 40 dB HL click level, (2) in 22 patients with symmetrical cochlear hearing loss at 90 dB HL, corresponding to 45-80 dB SL, and (3) in 45 patients with asymetrical cochlear hearing loss with interaural recruitment, at 90 dB HL on one hand and at a click sensation level corresponding to 90 dB HL in the poorer ear (range 10-75 dB SL) on the other hand. In the normal hearing group the ILDs did not exceed 0.2 ms except in one case at 40 dB HL (0.3 ms). In the symmetrical cochlear loss group the ILD did not exceed 0.2 ms in any patient. In the asymmetrical cochlear loss group the ILD at 90 dB HL exceeded 0.2 ms in 12 cases, but only in four cases after correction for pure tone hearing loss at 4 kHz by 0.1 for each 10 dB above 50 dB HL; at equal sensation levels the ILDs were all zero or negative meaning that the wave V latency was shorter on stimulation of the poorer ear. Assuming ILD to be a valid discriminator between cochlear and retrocochlear lesions, the corrected ILD at equal click hearing levels (90 dB HL), with the critical value set at 0.2 ms, thus gave a 9% false-positive rate whereas the ILS at equal sensation levels, with the critical value set at zero, gave no false-positives. It still remains to be shown that the latter criterion will not increase the number of false-negative results in retrocochlear lesions.

  17. Different Times?

    NARCIS (Netherlands)

    A. van den Broek; W.P. Knulst; K. Breedveld

    1999-01-01

    Original title: Naar andere tijden? The report Different times? Time use and time structuring in the Netherlands, 1975-1995 (Naar andere tijden? Tijdsbesteding en tijdsordening in Nederland, 1975-1995) paints a picture of the way in which the Dutch spend the 168 hours that are available each

  18. Different Times?

    NARCIS (Netherlands)

    A. van den Broek; W.P. Knulst; K. Breedveld

    1999-01-01

    Original title: Naar andere tijden? The report Different times? Time use and time structuring in the Netherlands, 1975-1995 (Naar andere tijden? Tijdsbesteding en tijdsordening in Nederland, 1975-1995) paints a picture of the way in which the Dutch spend the 168 hours that are available each week.

  19. Different Times?

    NARCIS (Netherlands)

    A. van den Broek; W.P. Knulst; K. Breedveld

    1999-01-01

    Original title: Naar andere tijden? The report Different times? Time use and time structuring in the Netherlands, 1975-1995 (Naar andere tijden? Tijdsbesteding en tijdsordening in Nederland, 1975-1995) paints a picture of the way in which the Dutch spend the 168 hours that are available each week.

  20. Bat Azimuthal Echolocation Using Interaural Level Differences: Modeling and Implementation by a VLSI-Based Hardware System

    Science.gov (United States)

    2006-01-01

    system ( Tsividis , 1997). Vdd Vτ Vw spkIn isyn v i M1 M4 M5 M2 M3 M6 M8 M7 C vc Iτ Figure 7.2: The basic synapse circuit. The pin “spkIn” receives the...Comput. Neurosci. 20(2):137–152. Tsividis Y (1997) Externally linear, time-invariant systems and their application to companding signal processors

  1. Similar Impacts of the Interaural Delay and Interaural Correlation on Binaural Gap Detection.

    Science.gov (United States)

    Kong, Lingzhi; Xie, Zilong; Lu, Lingxi; Qu, Tianshu; Wu, Xihong; Yan, Jun; Li, Liang

    2015-01-01

    The subjective representation of the sounds delivered to the two ears of a human listener is closely associated with the interaural delay and correlation of these two-ear sounds. When the two-ear sounds, e.g., arbitrary noises, arrive simultaneously, the single auditory image of the binaurally identical noises becomes increasingly diffuse, and eventually separates into two auditory images as the interaural correlation decreases. When the interaural delay increases from zero to several milliseconds, the auditory image of the binaurally identical noises also changes from a single image to two distinct images. However, measuring the effect of these two factors on an identical group of participants has not been investigated. This study examined the impacts of interaural correlation and delay on detecting a binaurally uncorrelated fragment (interaural correlation = 0) embedded in the binaurally correlated noises (i.e., binaural gap or break in interaural correlation). We found that the minimum duration of the binaural gap for its detection (i.e., duration threshold) increased exponentially as the interaural delay between the binaurally identical noises increased linearly from 0 to 8 ms. When no interaural delay was introduced, the duration threshold also increased exponentially as the interaural correlation of the binaurally correlated noises decreased linearly from 1 to 0.4. A linear relationship between the effect of interaural delay and that of interaural correlation was described for listeners participating in this study: a 1 ms increase in interaural delay appeared to correspond to a 0.07 decrease in interaural correlation specific to raising the duration threshold. Our results imply that a tradeoff may exist between the impacts of interaural correlation and interaural delay on the subjective representation of sounds delivered to two human ears.

  2. Similar Impacts of the Interaural Delay and Interaural Correlation on Binaural Gap Detection.

    Directory of Open Access Journals (Sweden)

    Lingzhi Kong

    Full Text Available The subjective representation of the sounds delivered to the two ears of a human listener is closely associated with the interaural delay and correlation of these two-ear sounds. When the two-ear sounds, e.g., arbitrary noises, arrive simultaneously, the single auditory image of the binaurally identical noises becomes increasingly diffuse, and eventually separates into two auditory images as the interaural correlation decreases. When the interaural delay increases from zero to several milliseconds, the auditory image of the binaurally identical noises also changes from a single image to two distinct images. However, measuring the effect of these two factors on an identical group of participants has not been investigated. This study examined the impacts of interaural correlation and delay on detecting a binaurally uncorrelated fragment (interaural correlation = 0 embedded in the binaurally correlated noises (i.e., binaural gap or break in interaural correlation. We found that the minimum duration of the binaural gap for its detection (i.e., duration threshold increased exponentially as the interaural delay between the binaurally identical noises increased linearly from 0 to 8 ms. When no interaural delay was introduced, the duration threshold also increased exponentially as the interaural correlation of the binaurally correlated noises decreased linearly from 1 to 0.4. A linear relationship between the effect of interaural delay and that of interaural correlation was described for listeners participating in this study: a 1 ms increase in interaural delay appeared to correspond to a 0.07 decrease in interaural correlation specific to raising the duration threshold. Our results imply that a tradeoff may exist between the impacts of interaural correlation and interaural delay on the subjective representation of sounds delivered to two human ears.

  3. Low frequency eardrum directionality in the barn owl induced by sound transmission through the interaural canal

    DEFF Research Database (Denmark)

    Kettler, Lutz; Christensen-Dalsgaard, Jakob; Larsen, Ole Næsbye

    2016-01-01

    The middle ears of birds are typically connected by interaural cavities that form a cranial canal. Eardrums coupled in this manner may function as pressure difference receivers rather than pressure receivers. Hereby, the eardrum vibrations become inherently directional. The barn owl also has...... a large interaural canal, but its role in barn owl hearing and specifically in sound localization has been controversial so far. We discuss here existing data and the role of the interaural canal in this species and add a new dataset obtained by laser Doppler vibrometry in a free-field setting....... Significant sound transmission across the interaural canal occurred at low frequencies. The sound transmission induces considerable eardrum directionality in a narrow band from 1.5 to 3.5 kHz. This is below the frequency range used by the barn owl for locating prey, but may conceivably be used for locating...

  4. Low frequency eardrum directionality in the barn owl induced by sound transmission through the interaural canal.

    Science.gov (United States)

    Kettler, Lutz; Christensen-Dalsgaard, Jakob; Larsen, Ole Næsbye; Wagner, Hermann

    2016-10-01

    The middle ears of birds are typically connected by interaural cavities that form a cranial canal. Eardrums coupled in this manner may function as pressure difference receivers rather than pressure receivers. Hereby, the eardrum vibrations become inherently directional. The barn owl also has a large interaural canal, but its role in barn owl hearing and specifically in sound localization has been controversial so far. We discuss here existing data and the role of the interaural canal in this species and add a new dataset obtained by laser Doppler vibrometry in a free-field setting. Significant sound transmission across the interaural canal occurred at low frequencies. The sound transmission induces considerable eardrum directionality in a narrow band from 1.5 to 3.5 kHz. This is below the frequency range used by the barn owl for locating prey, but may conceivably be used for locating conspecific callers.

  5. Better time-intensity trade revealed by bilateral giant magnetostrictive bone conduction.

    Science.gov (United States)

    Kuroki, Sozo; Kaga, Kimitaka

    2006-01-23

    Sound lateralization tests were performed to compare the magnet coil bone-conduction headphone with the giant magnetostrictive bone-conduction headphone using 18 healthy participants. Although, no significant difference between these bone-conduction headphones was obtained for the interaural time difference and interaural intensity difference, a significant difference was obtained for the time-intensity trade. This revealed that the difference between the headphones is apparent in the integration of the heterogeneous sensations of the time and intensity difference at the cognitive level, but no difference is apparent between the homogeneous sensations of the discrimination of interaural time difference or interaural intensity difference at the sensory level. It was concluded that the difference at the cognitive level indicates the better performance of the giant magnetostrictive headphone.

  6. Atenuação interaural: estudo comparativo com dois tipos de transdutores Interaural attenuation: comparative study with two types of transducers

    Directory of Open Access Journals (Sweden)

    Juliana Maria Pires Ramos

    2009-01-01

    Full Text Available OBJETIVO: Comparar os valores da atenuação interaural em um grupo de indivíduos com anacusia unilateral utilizando os fones de inserção e os supraaurais. MÉTODOS: Quinze indivíduos com anacusia unilateral foram submetidos à pesquisa do limiar de detecção de voz e à audiometria tonal liminar com os diferentes transdutores: fones TDH39 supraaurais e os fones de inserção ER-3A. Estes procedimentos foram realizados sem mascaramento contralateral. A subtração entre o limiar da melhor orelha e o limiar não mascarado da orelha anacúsica forneceu o tamanho da atenuação interaural para as frequências de 250 a 8000 Hz e para os estímulos de fala. RESULTADOS: Em todas as frequências e para os estímulos de fala, houve diferença significativa favorecendo o ER-3A. Não houve diferença significativa entre sexo e grupo etário. CONCLUSÃO: Os fones de inserção forneceram maior atenuação interaural quando comparados aos supraaurais. Esta maior atenuação pode ser muito útil na prática da audiologia, especialmente em relação ao uso do mascaramento.PURPOSE: To compare interaural attenuation values in a group of individuals with unilateral anacusis using supra-aural earphones and insert earphones. METHODS: Fifteen subjects with complete unilateral deafness underwent pure-tone audiometry and determination of speech detection threshold with two different transducers: TDH-39 supra-aural earphones, and ER-3A insert earphone. These procedures were carried out without contralateral masking. Interaural attenuation effects for the frequencies ranging from 250 to 8000 Hz were obtained by subtracting the unmasked threshold of the deaf ear from the threshold obtained for the normal ear. RESULTS: Interaural attenuation values were significantly greater when obtained with ER-3A earphones, for all frequencies and for speech stimuli. No differences were found between genders and age ranges. CONCLUSION: Insert earphones provided greater interaural

  7. Interaural Place-Mismatch Estimation With Two-Formant Vowels in Unilateral Cochlear- Implant Users

    DEFF Research Database (Denmark)

    Guérit, François; Santurette, Sébastien; Chalupper, Josef

    procedures such as interaural pitch-matching are rather tedious and time-consuming. Here, an alternative method using two-formant vowels was developed and tested. Methods Eight normal-hearing (NH) listeners were presented synthesized two-formant vowels embedded between consonants /t/ and /k/, with first......-choice task which of 6 vowels they perceived for different [F1, F2] combinations. Ten CI users (5 bimodal and 5 single-sided deaf) performed the same task for F1 presented acoustically to the non-CI ear and F2 presented either acoustically to the same ear or electrically to the CI ear. Results After some...... training, all NH listeners were able to fuse the unaltered F1 and vocoded F2 into a single vowel percept, and vowel distributions could be reliably derived in 7 listeners. Vocoder simulations of reduced CI insertion depth led to clear vowel-distribution shifts in these listeners. However, these shifts were...

  8. Lateralization of noise-burst trains based on onset and ongoing interaural delays.

    Science.gov (United States)

    Freyman, Richard L; Balakrishnan, Uma; Zurek, Patrick M

    2010-07-01

    The lateralization of 250-ms trains of brief noise bursts was measured using an acoustic pointing technique. Stimuli were designed to assess the contribution of the interaural time delay (ITD) of the onset binaural burst relative to that of the ITDs in the ongoing part of the train. Lateralization was measured by listeners' adjustments of the ITD of a pointer stimulus, a 50-ms burst of noise, to match the lateral position of the target train. Results confirmed previous reports of lateralization dominance by the onset burst under conditions in which the train is composed of frozen tokens and the ongoing part contains multiple ambiguous interaural delays. In contrast, lateralization of ongoing trains in which fresh noise tokens were used for each set of two alternating (left-leading/right-leading) binaural pairs followed the ITD of the first pair in each set, regardless of the ITD of the onset burst of the entire stimulus and even when the onset burst was removed by gradual gating. This clear lateralization of a long-duration stimulus with ambiguous interaural delay cues suggests precedence mechanisms that involve not only the interaural cues at the beginning of a sound, but also the pattern of cues within an ongoing sound.

  9. Binaural dereverberation based on interaural coherence histograms

    DEFF Research Database (Denmark)

    Westermann, Adam; Buchholz, Jorg M.; Dau, Torsten

    2013-01-01

    A binaural dereverberation algorithm is presented that utilizes the properties of the interaural coherence (IC) inspired by the concepts introduced in Allen et al. [J. Acoust. Soc. Am. 62, 912-915 (1977)]. The algorithm introduces a non-linear sigmoidal coherence-to-gain mapping that is controlled...... of the proposed algorithm was objectively and subjectively evaluated in terms of its impacts on the amount of reverberation and overall quality. A binaural spectral subtraction method based on Lebart et al. [Acta Acust. Acust. 87, 359-366 (2001)] and a binaural version of the original method of Allen et al. were...... considered as reference systems. The results revealed that the proposed coherence-based approach is most successful in acoustic scenarios that exhibit a significant spread in the coherence distribution where direct sound and reverberation can be segregated. This dereverberation algorithm is thus particularly...

  10. Effects of envelope shape on interaural envelope delay sensitivity in acoustic and electric hearing.

    Science.gov (United States)

    Laback, Bernhard; Zimmermann, Inge; Majdak, Piotr; Baumgartner, Wolf-Dieter; Pok, Stefan-Marcel

    2011-09-01

    The envelope shape is important for the perception of interaural time difference (ITD) in the envelope as supported by the improved sensitivity for transposed tones compared to sinusoidally amplitude-modulated (SAM) tones. The present study investigated the effects of specific envelope parameters in nine normal-hearing (NH) and seven cochlear-implant (CI) listeners, using high-rate carriers with 27-Hz trapezoidal modulation. In NH listeners, increasing the off time (the silent interval in each modulation cycle) up to 12 ms, increasing the envelope slope from 6 to 8 dB/ms, and increasing the peak level improved ITD sensitivity. The combined effect of the off time and slope accounts for the gain in sensitivity for transposed tones relative to SAM tones. In CI listeners, increasing the off time up to 20 ms improved sensitivity, but increasing the slope showed no systematic effect. A 27-pulses/s electric pulse train, representing a special case of modulation with infinitely steep slopes and maximum possible off time, yielded considerably higher sensitivity compared to the best condition with trapezoidal modulation. Overall, the results of this study indicate that envelope-ITD sensitivity could be improved by using CI processing schemes that simultaneously increase the off time and the peak level of the signal envelope. © 2011 Acoustical Society of America

  11. Binaural dereverberation based on interaural coherence histograms.

    Science.gov (United States)

    Westermann, Adam; Buchholz, Jörg M; Dau, Torsten

    2013-05-01

    A binaural dereverberation algorithm is presented that utilizes the properties of the interaural coherence (IC) inspired by the concepts introduced in Allen et al. [J. Acoust. Soc. Am. 62, 912-915 (1977)]. The algorithm introduces a non-linear sigmoidal coherence-to-gain mapping that is controlled by an online estimate of the present coherence statistics. The algorithm automatically adapts to a given acoustic environment and provides a stronger dereverberation effect than the original method presented in Allen et al. [J. Acoust. Soc. Am. 62, 912-915 (1977)] in most acoustic conditions. The performance of the proposed algorithm was objectively and subjectively evaluated in terms of its impacts on the amount of reverberation and overall quality. A binaural spectral subtraction method based on Lebart et al. [Acta Acust. Acust. 87, 359-366 (2001)] and a binaural version of the original method of Allen et al. were considered as reference systems. The results revealed that the proposed coherence-based approach is most successful in acoustic scenarios that exhibit a significant spread in the coherence distribution where direct sound and reverberation can be segregated. This dereverberation algorithm is thus particularly useful in large rooms for short source-receiver distances.

  12. Investigation of Persian Speech Interaural Attenuation in Adults

    Directory of Open Access Journals (Sweden)

    Fahimeh Hajiabolhassan

    2010-06-01

    Full Text Available Background and Aim: As clinical audiometry assessment of each ear needs to know interaural attenuation (IA, the aim of this study was to investigate Persian speech IA in adults.Methods: This cross-sectional, analytic study was performed on 50 normal hearing students (25 males, 25 females, aged 18-25 years old in Faculty of Rehabilitation, Tehran University of Medical Sciences. Speech reception threshold (SRT was determined with descending method with and without noise. Then speech IA for Persian spondaic words was caculated with TDH-39 earphones.Results: Mean speech IA was 53.06±3.25 dB. There was no significant difference between mean IA in males (53.88±2.93 dB and females (52.24±3.40 dB(p>0.05. The lowest IA was in females (45 dB and the highest IA was in males (60 dB. Mother’s language has no significant effect on speech IA.Conclusion: We may consider 45 dB as the lowest IA for Persian speech assessment, however generalization needs more study on a larger sample.

  13. Investigating Interaural Frequency-Place Mismatches via Bimodal Vowel Integration

    DEFF Research Database (Denmark)

    Guérit, François; Santurette, Sébastien; Chalupper, Josef;

    2014-01-01

    For patients having residual hearing in one ear and a cochlear implant (CI) in the opposite ear, interaural place-pitch mismatches might be partly responsible for the large variability in individual benefit. Behavioral pitch-matching between the two ears has been suggested as a way to individuali...

  14. Circuits for Processing Dynamic Interaural Intensity Disparities in the Inferior Colliculus

    Science.gov (United States)

    Pollak, George D.

    2013-01-01

    Interaural intensity disparities (IIDs), the cues all animals use to localize high frequency sounds, are initially processed in the lateral superior olive (LSO) by a subtractive process where inputs from one ear excite and inputs from the other ear inhibit LSO neurons. Such cells are called excitatory-inhibitory (EI) neurons and are prominent not only in the LSO but also in higher nuclei, which include the dorsal nucleus of the lateral lemniscus (DNLL) and inferior colliculus (IC). The IC is of particular interest since its EI cells receive diverse innervation patterns from a large number of lower nuclei, which include the DNLLs and LSOs, and thus comprise a population with diverse binaural properties. The first part of this review focuses on the circuits that create EI cells in the LSO, DNLL and IC. The second section then turns to the responses evoked by dynamic IIDs that change over time, as with multiple sounds that emanate from different regions of space or moving sound sources. I show that many EI neurons in the IC respond to dynamic IIDs in ways that are not predictable from their responses to static IIDs, IIDs presented one at a time. In the final section, results from in vivo whole cell recording in the IC are presented and address the connectional basis for the responsiveness to dynamic IIDs. The principal conclusion is that EI cells comprise a diverse population. The diversity is created by the particular set of inputs each EI type receives and is expressed in the differences in the responses to dynamic IIDs that are generated by those inputs. These results show that the construction of EI neurons in the IC imparts features that not only encode the location of an individual sound source, but also that allow animals to determine the direction of a moving sound and to focus and localize a single sound in midst of many sounds, as typically occurs in the daily lives of all animals. PMID:22343068

  15. Time Reference in Different Cultures.

    Science.gov (United States)

    Khairullin, Vladimir

    1993-01-01

    Discusses time references in Russian- and English-speaking cultures by means of Russian translation variants of works by twentieth-century English-language writers. Suggests the different attitudes toward time as manifested by these two distinct cultures. (HB)

  16. Modernity: Are Modern Times Different?

    Directory of Open Access Journals (Sweden)

    Lynn Hunt

    2014-12-01

    Full Text Available “Modernity” has recently been the subject of considerable discussion among historians. This article reviews some of the debates and argues that modernity is a problematic concept because it implies a complete rupture with “traditional” ways of life. Studies of key terms are undertaken with the aid of Google Ngrams. These show that “modernity,” “modern times,” and “traditional” —in English and other languages— have a history of their own. A brief analysis of the shift from a self oriented toward equilibrium to a self oriented toward stimulation demonstrates that modernity is not necessary to historical analysis.

  17. Monaural and interaural intensity discrimination: Level effects and the ``binaural advantage''

    Science.gov (United States)

    Stellmack, Mark A.; Viemeister, Neal F.; Byrne, Andrew J.

    2004-08-01

    This study examined whether the level effects seen in monaural intensity discrimination (Weber's law and the ``near miss'') in a two-interval task are also observed in discrimination of interaural intensity differences (IIDs) in a single-interval task. Both tasks were performed for various standard levels of 4-kHz pure tones and broadband noise. The Weber functions (10 log ΔI/I versus I in dB) in the monaural and binaural conditions were parallel. For noise, the Weber functions had slopes close to zero (Weber's law) while the Weber functions for the tones had a mean slope of -0.089 (near miss). The near miss for the monaural and binaural tasks with tones was eliminated when a high-pass masker was gated with the listening intervals. The near-miss was also observed for 250- and 1000-Hz tones in the binaural task despite overall decreased sensitivity to changes in IID at 1000 Hz. The binaural thresholds showed a small (about 2-dB) advantage over monaural thresholds only in the broadband noise conditions. More important, however, is the fact that the level effects seen monaurally are also seen binaurally. This suggests that the basic mechanisms responsible for Weber's law and the near miss are common to monaural and binaural processing.

  18. Assessing Subgroup Differences in Item Response Times.

    Science.gov (United States)

    Schnipke, Deborah L.; Pashley, Peter J.

    Differences in test performance on time-limited tests may be due in part to differential response-time rates between subgroups, rather than real differences in the knowledge, skills, or developed abilities of interest. With computer-administered tests, response times are available and may be used to address this issue. This study investigates…

  19. Time-intensity trade of bilaterally bone-conducted sounds in normal hearing subjects.

    Science.gov (United States)

    Schmerber, S; Sheykholeslami, K; Kermany, M H; Hotta, S; Kaga, K

    2003-01-01

    In an effort to examine the rules by which information of bilaterally applied bone-conducted signals arising from interaural time differences (ITD) and interaural intensity differences (IID) is combined, data were measured for continuous 500 Hz narrow-band noise at 60 dBHL in 30 normal-hearing subjects using a centering method. Time-intensity trading functions were obtained by means of a sound image shifted towards one side by presenting an ITD, and shifted back to a centered sound image by varying the IID in the same ear. ITD values were varied from -600 to +600 microseconds at 200 microseconds steps, where negative values indicate delays to the right ear. Time-intensity trading functions in response to bone-conducted signals showed significantly lower discrimination thresholds across IIDs, when compared to a control group with applied air-conducted signals. These findings can be interpreted as a constructive interference effect related to the intimate mechanism of bilateral bone conduction, where interaural time differences play a major role. Time-intensity trade of bilaterally bone-conducted sounds in normal-hearing subjects is the highly sensitive. The high speed of sound through the skull may be the main reason for the high sensitivity of time-intensity trading.

  20. Time perception and time perspective differences between adolescents and adults.

    Science.gov (United States)

    Siu, Nicolson Y F; Lam, Heidi H Y; Le, Jacqueline J Y; Przepiorka, Aneta M

    2014-09-01

    The present experiment aimed to investigate the differences in time perception and time perspective between subjects representing two developmental stages, namely adolescence and middle adulthood. Twenty Chinese adolescents aged 15-25 and twenty Chinese adults aged 35-55 participated in the study. A time discrimination task and a time reproduction task were implemented to measure the accuracy of their time perception. The Zimbardo Time Perspective Inventory (Short-Form) was adopted to assess their time orientation. It was found that adolescents performed better than adults in both the time discrimination task and the time reproduction task. Adolescents were able to differentiate different time intervals with greater accuracy and reproduce the target duration more precisely. For the time reproduction task, it was also found that adults tended to overestimate the duration of the target stimuli while adolescents were more likely to underestimate it. As regards time perspective, adults were more future-oriented than adolescents, whereas adolescents were more present-oriented than adults. No significant relationship was found between time perspective and time perception.

  1. Demographic Group Differences in Adolescents' Time Attitudes

    Science.gov (United States)

    Andretta, James R.; Worrell, Frank C.; Mello, Zena R.; Dixson, Dante D.; Baik, Sharon H.

    2013-01-01

    In the present study, we examined demographic differences in time attitudes in a sample of 293 adolescents. Time attitudes were measured using the Adolescent Time Attitude Scale (Mello & Worrell, 2007; Worrell, Mello, & Buhl, 2011), which assesses positive and negative attitudes toward the past, the present, and the future. Generally, African…

  2. Time-dependent problems and difference methods

    CERN Document Server

    Gustafsson, Bertil; Oliger, Joseph

    2013-01-01

    Praise for the First Edition "". . . fills a considerable gap in the numerical analysis literature by providing a self-contained treatment . . . this is an important work written in a clear style . . . warmly recommended to any graduate student or researcher in the field of the numerical solution of partial differential equations."" -SIAM Review Time-Dependent Problems and Difference Methods, Second Edition continues to provide guidance for the analysis of difference methods for computing approximate solutions to partial differential equations for time-de

  3. Silicon timing response to different laser light

    Energy Technology Data Exchange (ETDEWEB)

    Ronzhin, Anatoly [Fermilab

    2017-01-17

    The purpose of the work was to measure pulse shape and timing response of the silicon under picosecond lasers light illumination. Timing response for different laser wavelengths, 405 nm, 635 nm and 1060 nm was a point of interest. The performed measurements could be useful for CMS HGCal upgrade

  4. Young people's leisure time: Gender differences

    Directory of Open Access Journals (Sweden)

    Marina Videnović

    2010-06-01

    Full Text Available Over the last three decades, topics relating to young peoples leisure time have become increasingly more present in academic literature. Among the numerous studies that delve into this subject, results point towards a relationship between the way teenagers spend their leisure time and their gender. In this study we wanted to answer the question if gender differences were evident in the way secondary school students in Serbia spent their leisure time. This problem was not looked into in more detail among secondary school students in Serbia. We conducted a survey on a sample of 922 secondary school teenagers from the 1st to 4th grade(ages 15–19 from nine Serbian towns. Research in this field commonly uses the rating scale. In this paper we have constructed an instrument that represents a methodological innovation in approaching a particular set of problems. It was a questionnaire. The task was to name all the activities they participated in, and the time frame in which the activities took place, over the course of one weekday and the Saturday of the previous week. The activities which best differentiate these two groups of surveyed teenagers are: sports, studying, computer use, spending time at friends’ homes and grooming. We did not discover differences in participating in creative activities while foreign studies show that such activities are more typical for girls.

  5. Envelope enhancement increases cortical sensitivity to interaural envelope delays with acoustic and electric hearing.

    Directory of Open Access Journals (Sweden)

    Douglas E H Hartley

    Full Text Available Evidence from human psychophysical and animal electrophysiological studies suggests that sensitivity to interaural time delay (ITD in the modulating envelope of a high-frequency carrier can be enhanced using half-wave rectified stimuli. Recent evidence has shown potential benefits of equivalent electrical stimuli to deaf individuals with bilateral cochlear implants (CIs. In the current study we assessed the effects of envelope shape on ITD sensitivity in the primary auditory cortex of normal-hearing ferrets, and profoundly-deaf animals with bilateral CIs. In normal-hearing animals, cortical sensitivity to ITDs (±1 ms in 0.1-ms steps was assessed in response to dichotically-presented i sinusoidal amplitude-modulated (SAM and ii half-wave rectified (HWR tones (100-ms duration; 70 dB SPL presented at the best-frequency of the unit over a range of modulation frequencies. In separate experiments, adult ferrets were deafened with neomycin administration and bilaterally-implanted with intra-cochlear electrode arrays. Electrically-evoked auditory brainstem responses (EABRs were recorded in response to bipolar electrical stimulation of the apical pair of electrodes with singe biphasic current pulses (40 µs per phase over a range of current levels to measure hearing thresholds. Subsequently, we recorded cortical sensitivity to ITDs (±800 µs in 80-µs steps within the envelope of SAM and HWR biphasic-pulse trains (40 µs per phase; 6000 pulses per second, 100-ms duration over a range of modulation frequencies. In normal-hearing animals, nearly a third of cortical neurons were sensitive to envelope-ITDs in response to SAM tones. In deaf animals with bilateral CI, the proportion of ITD-sensitive cortical neurons was approximately a fifth in response to SAM pulse trains. In normal-hearing and deaf animals with bilateral CI the proportion of ITD sensitive units and neural sensitivity to ITDs increased in response to HWR, compared with SAM stimuli

  6. Regional differences in waiting time to pregnancy

    DEFF Research Database (Denmark)

    Juul, Svend; Karmaus, W; Olsen, Jørn

    1999-01-01

    of the pregnancies were planned (64%) and approximately 14% were the result of contraceptive failures. The study shows that smoking, body mass index, age and parity did not explain the differences in fecundity found between the centres. Regional differences in fecundity exist and the causes may be genetic or due......The objective of this study was examine geographical variation in couple fecundity in Europe. The study was based upon all recently pregnant (or still pregnant) women within well-defined geographical areas in Europe (Denmark, Germany, Italy, Sweden and France) at a given time period in 1992....... Altogether, 4035 women responded to a highly structured questionnaire. Highest fecundity was found in Southern Italy and Northern Sweden; lowest fecundity was seen in data from the East German centre. Approximately 16% of the study population had a waiting time of more than 12 months to become pregnant. Most...

  7. Significance of time scale differences in psychophysics.

    Science.gov (United States)

    Klonowski, W

    2009-02-01

    We present modeling of both rational processes (thoughts) and emotional processes (feelings) on a two-dimensional lattice and on extremely simplified two-dimensional phase space of the brain. Our purpose is to analyze influence of differences in time-scales of various types of processes. In particular, we show that no 'central executive structure' between consciousness and unconsciousness, the existence of which was suggested by psychologists, is not needed.

  8. Automation: is it really different this time?

    Science.gov (United States)

    Wajcman, Judy

    2017-03-01

    This review examines several recent books that deal with the impact of automation and robotics on the future of jobs. Most books in this genre predict that the current phase of digital technology will create massive job loss in an unprecedented way, that is, that this wave of automation is different from previous waves. Uniquely digital technology is said to automate professional occupations for the first time. This review critically examines these claims, puncturing some of the hyperbole about automation, robotics and Artificial Intelligence. The review argues for a more nuanced analysis of the politics of technology and provides some critical distance on Silicon Valley's futurist discourse. Only by insisting that futures are always social can public bodies, rather than autonomous markets and endogenous technologies, become central to disentangling, debating and delivering those futures.

  9. The influence of aging on interaural asymmetries in middle latency response amplitude.

    Science.gov (United States)

    Weihing, Jeffrey; Musiek, Frank

    2014-04-01

    ear effects, variability for absolute amplitude measures was compared to ear effect variability using the Pitman t-test. To examine potential effects of background noise and aging, data were analyzed using a mixed-factorial analysis of variance with the within-subjects factor "background noise" and the between-subjects factor "age group." Within-group variability was significantly reduced by calculating ear effects for the youngest group only. Additionally, the oldest adults in the present sample showed significantly larger ear effects than younger and middle-aged adults. This effect did not appear to be a result of differences in peripheral hearing sensitivity. Finally, introducing noise into the paradigm did not influence the observed effects. Ear effects become larger in older adults possibly as a result of age-related changes in the subcortical and/or cortical generators of the MLR. Failure of the ear effect calculation to reduce within-group variability in the middle-aged and older adults suggests that interaural asymmetries in MLR amplitude become more variable across participants who are older than 50 yr. Information obtained from this measure may benefit the development of treatment plans for older adults with hearing difficulties. American Academy of Audiology.

  10. Interaural bimodal pitch matching with two-formant vowels

    DEFF Research Database (Denmark)

    2013-01-01

    practice. Behavioral pitch matching between the two ears has also been suggested, but has been shown to be tedious and unreliable. Here, an alternative method using two-formant vowels was developed and tested with a vocoder system simulating different CI insertion depths. The hypothesis was that patients...... may more easily identify vowels than perform a classical pitch-matching task. A spectral shift is inferred by comparing vowel spaces, measured by presenting the first formant in the HA and the second either in the HA or the CI. Preliminary results suggest that pitch mismatches can be derived from...... such vowel spaces. In order to take auditory adaptation in individual patients into account, the method will be tested with CI patients with contralateral residual hearing....

  11. Interaural bimodal pitch matching with two-formant vowels

    DEFF Research Database (Denmark)

    Guerit, Francois Marie Louis Paul; Chalupper, Josef; Santurette, Sébastien

    practice. Behavioral pitch matching between the two ears has also been suggested, but has been shown to be tedious and unreliable. Here, an alternative method using two-formant vowels was developed and tested with a vocoder system simulating different CI insertion depths. The hypothesis was that patients...... may more easily identify vowels than perform a classical pitch-matching task. A spectral shift is inferred by comparing vowel spaces, measured by presenting the first formant in the HA and the second either in the HA or the CI. Preliminary results suggest that pitch mismatches can be derived from...... such vowel spaces. In order to take auditory adaptation in individual patients into account, the method will be tested with CI patients with contralateral residual hearing....

  12. Exploratory analysis on the binaural characteristics of the rowing sound

    DEFF Research Database (Denmark)

    Hoffmann, Pablo F.; Hammershøi, Dorte; Ruffaldi, Emanuele

    2011-01-01

    Differences between the signals captured at the entrances to the left and right ears are generally quantified by interaural time differences (ITDs), interaural level differences (ILDs) and interaural crosscorrelation (IC). Here, we attempt to gain knowledge on the changes of these interaural param...

  13. Same but Different: Space, Time and Narrative

    Science.gov (United States)

    Bansel, Peter

    2013-01-01

    In this paper, I give an account of the ways in which narratives and identities change over space and time. I give an account of a mobile and changing human subject, one who does not simply express or represent her- or himself through narrative, but is constructed and reconstructed through narrative. I draw on Paul Ricoeur's concepts of "narrative…

  14. Same but Different: Space, Time and Narrative

    Science.gov (United States)

    Bansel, Peter

    2013-01-01

    In this paper, I give an account of the ways in which narratives and identities change over space and time. I give an account of a mobile and changing human subject, one who does not simply express or represent her- or himself through narrative, but is constructed and reconstructed through narrative. I draw on Paul Ricoeur's concepts of "narrative…

  15. Liquidity crises on different time scales

    Science.gov (United States)

    Corradi, Francesco; Zaccaria, Andrea; Pietronero, Luciano

    2015-12-01

    We present an empirical analysis of the microstructure of financial markets and, in particular, of the static and dynamic properties of liquidity. We find that on relatively large time scales (15 min) large price fluctuations are connected to the failure of the subtle mechanism of compensation between the flows of market and limit orders: in other words, the missed revelation of the latent order book breaks the dynamical equilibrium between the flows, triggering the large price jumps. On smaller time scales (30 s), instead, the static depletion of the limit order book is an indicator of an intrinsic fragility of the system, which is related to a strongly nonlinear enhancement of the response. In order to quantify this phenomenon we introduce a measure of the liquidity imbalance present in the book and we show that it is correlated to both the sign and the magnitude of the next price movement. These findings provide a quantitative definition of the effective liquidity, which proves to be strongly dependent on the considered time scales.

  16. Individual Differences in Time-Sharing Performance

    Science.gov (United States)

    1977-01-01

    relative to solitary task performance levels (e.g., North and Gopher, 1975; Parker, 1964; Sterky and Eysenck , 1965). In attempting such an analysis...Sterky, K. and Eysenck , H. J. Pursuit rotor performance as a function of different degrees of distraction. Life Sciences, 1965) 4, 889-897. Trankell, A

  17. Part-time and full-time medical specialists, are there differences in allocation of time?

    Directory of Open Access Journals (Sweden)

    Groenewegen Peter P

    2006-03-01

    Full Text Available Abstract Background An increasing number of medical specialists prefer to work part-time. This development can be found worldwide. Problems to be faced in the realization of part-time work in medicine include the division of night and weekend shifts, as well as communication between physicians and continuity of care. People tend to think that physicians working part-time are less devoted to their work, implying that full-time physicians complete a greater number of tasks. The central question in this article is whether part-time medical specialists allocate their time differently to their tasks than full-time medical specialists. Methods A questionnaire was sent by mail to all internists (N = 817, surgeons (N = 693 and radiologists (N = 621 working in general hospitals in the Netherlands. Questions were asked about the actual situation, such as hours worked and night and weekend shifts. The response was 53% (n = 411 for internists, 52% (n = 359 for surgeons, and 36% (n = 213 for radiologists. Due to non-response on specific questions there were 367 internists, 316 surgeons, and 71 radiologists included in the analyses. Multilevel analyses were used to analyze the data. Results Part-time medical specialists do not spend proportionally more time on direct patient care. With respect to night and weekend shifts, part-time medical specialists account for proportionally more or an equal share of these shifts. The number of hours worked per FTE is higher for part-time than for full-time medical specialists, although this difference is only significant for surgeons. Conclusion In general, part-time medical specialists do their share of the job. However, we focussed on input only. Besides input, output like the numbers of services provided deserves attention as well. The trend in medicine towards more part-time work has an important consequence: more medical specialists are needed to get the work done. Therefore, a greater number of medical specialists

  18. Time-intensity trading in bilateral congenital aural atresia patients.

    Science.gov (United States)

    Schmerber, Sébastien; Sheykholeslami, Kianoush; Kermany, Mohammad Habiby; Hotta, Shoko; Kaga, Kimitaka

    2005-04-01

    In an effort to examine the rules by which information of bilaterally applied bone-conducted signals arising from interaural time differences (ITD) and interaural intensity differences (IID) is combined, data were measured for continuous 500 Hz narrow band noise at 65-70 dB HL in 11 patients with bilateral congenital aural atresia. Time-intensity trading functions were obtained by shifting the sound image towards one side using ITD, and shifting back to a centered sound image by varying the IID in the same ear (auditory midline task). ITD values were varied from -600 to +600 micros at 200 micros steps, where negative values indicate delays to the right ear. The results indicate that time-intensity trading is present in patients with bilateral aural atresia. The gross response properties of time-intensity trading in response to bone-conducted signals were comparable in patients with bilateral aural atresia and normal-hearing subjects, though there was a larger inter-subject variability and higher discrimination thresholds across IIDs in the atresia group. These results suggest that the mature auditory brainstem has a potential to employ binaural cues later in life, although to a restricted degree. A binaural fitting of a bone-conducted hearing aid might optimize binaural hearing and improve sound lateralization, and we recommend now systematically bilateral fitting in aural atresia patients.

  19. Laboratory rats (Rattus norvegicus) do not use binaural phase differences to localize sound.

    Science.gov (United States)

    Wesolek, Christina M; Koay, Gimseong; Heffner, Rickye S; Heffner, Henry E

    2010-06-14

    The ability of Norway rats to use binaural time- and intensity-difference cues to localize sound was investigated by determining their ability to localize pure tones from 500 Hz to 32 kHz. In addition, their ability to use the binaural time cues present in the envelope of a signal was determined by presenting them with a 1-kHz tone that was amplitude modulated at either 250 or 500 Hz. Although the animals were easily able to localize tones above 2 kHz, indicating that they could use the binaural intensity-difference cue, they were virtually unable to localize the lower-frequency stimuli, indicating that they could not use the binaural phase (time) cue. Although some animals showed a residual ability to localize low-frequency tones, control tests indicated that they were using the transient interaural intensity difference in the onset of a sound that exists after it reaches the near ear but before it reaches the far ear. Thus, in contrast to earlier studies, we conclude that the Norway rat is unable to use the ongoing time cues available in low-frequency tones to localize sound, raising the possibility that the rat may not use interaural time differences to localize sound. 2010 Elsevier B.V. All rights reserved.

  20. Time-Varying Distortions of Binaural Information by Bilateral Hearing Aids

    Directory of Open Access Journals (Sweden)

    Andrew D. Brown

    2016-09-01

    Full Text Available In patients with bilateral hearing loss, the use of two hearing aids (HAs offers the potential to restore the benefits of binaural hearing, including sound source localization and segregation. However, existing evidence suggests that bilateral HA users’ access to binaural information, namely interaural time and level differences (ITDs and ILDs, can be compromised by device processing. Our objective was to characterize the nature and magnitude of binaural distortions caused by modern digital behind-the-ear HAs using a variety of stimuli and HA program settings. Of particular interest was a common frequency-lowering algorithm known as nonlinear frequency compression, which has not previously been assessed for its effects on binaural information. A binaural beamforming algorithm was also assessed. Wide dynamic range compression was enabled in all programs. HAs were placed on a binaural manikin, and stimuli were presented from an arc of loudspeakers inside an anechoic chamber. Stimuli were broadband noise bursts, 10-Hz sinusoidally amplitude-modulated noise bursts, or consonant–vowel–consonant speech tokens. Binaural information was analyzed in terms of ITDs, ILDs, and interaural coherence, both for whole stimuli and in a time-varying sense (i.e., within a running temporal window across four different frequency bands (1, 2, 4, and 6 kHz. Key findings were: (a Nonlinear frequency compression caused distortions of high-frequency envelope ITDs and significantly reduced interaural coherence. (b For modulated stimuli, all programs caused time-varying distortion of ILDs. (c HAs altered the relationship between ITDs and ILDs, introducing large ITD–ILD conflicts in some cases. Potential perceptual consequences of measured distortions are discussed.

  1. Time-Varying Distortions of Binaural Information by Bilateral Hearing Aids

    Science.gov (United States)

    Rodriguez, Francisco A.; Portnuff, Cory D. F.; Goupell, Matthew J.; Tollin, Daniel J.

    2016-01-01

    In patients with bilateral hearing loss, the use of two hearing aids (HAs) offers the potential to restore the benefits of binaural hearing, including sound source localization and segregation. However, existing evidence suggests that bilateral HA users’ access to binaural information, namely interaural time and level differences (ITDs and ILDs), can be compromised by device processing. Our objective was to characterize the nature and magnitude of binaural distortions caused by modern digital behind-the-ear HAs using a variety of stimuli and HA program settings. Of particular interest was a common frequency-lowering algorithm known as nonlinear frequency compression, which has not previously been assessed for its effects on binaural information. A binaural beamforming algorithm was also assessed. Wide dynamic range compression was enabled in all programs. HAs were placed on a binaural manikin, and stimuli were presented from an arc of loudspeakers inside an anechoic chamber. Stimuli were broadband noise bursts, 10-Hz sinusoidally amplitude-modulated noise bursts, or consonant–vowel–consonant speech tokens. Binaural information was analyzed in terms of ITDs, ILDs, and interaural coherence, both for whole stimuli and in a time-varying sense (i.e., within a running temporal window) across four different frequency bands (1, 2, 4, and 6 kHz). Key findings were: (a) Nonlinear frequency compression caused distortions of high-frequency envelope ITDs and significantly reduced interaural coherence. (b) For modulated stimuli, all programs caused time-varying distortion of ILDs. (c) HAs altered the relationship between ITDs and ILDs, introducing large ITD–ILD conflicts in some cases. Potential perceptual consequences of measured distortions are discussed. PMID:27698258

  2. Time difference based measurement of ultrasonic cavitations in wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    朱昌平

    2016-01-01

    Intensity of cavitation is significant in ultrasonic wastewater treatment, but is complicated to measure.A time difference based method of ultrasonic cavitation measurement is proposed.The time differences at different powers of 495kHz ultrasonic are measured in experiment in comparison with conductimetric method.Simulation results show that time difference and electrical conductivity are both approximately positive proportional to the ultrasonic power.The degradation of PNP solution verifies the availability in wastewater treatment by using ultrasonic.

  3. A comparison of inter-aural attenuation with the Etymotic ER-3A insert earphone and the Telephonics TDH-39 supra-aural earphone.

    Science.gov (United States)

    Munro, K J; Agnew, N

    1999-08-01

    One of the many reported advantages of the insert earphone over the supra-aural earphone is increased inter-aural attenuation (IA). Minimum values of IA determine the need for masking of the non-test ear in air-conduction audiometry. The aim of the present study was to measure inter-aural attenuation for the Etymotic Research ER-3A insert earphone (with deep and shallow insertion of the ear plug within the ear canal) and compare this with the supra-aural Telephonics TDH-39/MX41-AR earphone/cushion combination. Subjects were 18 adults ranging in age from 38 to 68 years (mean 50 years). Each subject had no hearing in one ear following translabyrinthine surgery for removal of an acoustic neuroma. The opposite ear had hearing thresholds better than 40 dB HL and an air-bone gap of less than 10 dB at any audiometric frequency. Pure tone air-conduction thresholds were obtained in the range 0.25-8 kHz. Deep insertion of the insert earphone was deemed to occur when the outside edge of the ear plug was flush with the entrance of the ear canal. Shallow insertion was deemed to occur when half of the ear plug (6 mm) was inside the entrance of the ear canal. IA was defined operationally as the difference between the good-ear and poor-ear not-masked air conduction threshold for a given audiometric frequency and earphone. The results show that the TDH-39/MX41-AR combination provides a median IA of approximately 60 dB with a lower limit of approximately 45 dB. Greater IA was obtained with the ER-3A insert earphone but this depended on the depth of insertion. With a deep insertion, the 1A values were some 15-20 dB greater than with the supra-aural earphone. Although frequency-specific IA values are provided, a simple rule of thumb is to apply masking to the non-test ear when the pure tone airconduction signal from the ER-3A insert earphone exceeds the bone conduction threshold of the non-test ear by 55 dB HL or more. If it is not possible to obtain a deep insertion depth this value

  4. Part-time and full-time medical specialists, are there differences in allocation of time?

    NARCIS (Netherlands)

    Jong, J.D. de; Heiligers, P.; Groenewegen, P.P.; Hingstman, L.

    2006-01-01

    BACKGROUND: An increasing number of medical specialists prefer to work part-time. This development can be found worldwide. Problems to be faced in the realization of part-time work in medicine include the division of night and weekend shifts, as well as communication between physicians and

  5. Different Starting Distances Affect 5-m Sprint Times.

    Science.gov (United States)

    Altmann, Stefan; Hoffmann, Marian; Kurz, Gunther; Neumann, Rainer; Woll, Alexander; Haertel, Sascha

    2015-08-01

    The purpose of this study was to quantify the effect of different starting distances on 5-m sprint time and the accuracy of the initial timing gate. A single-beam timing gate system (1 m high) was used to measure 5-m sprint time in 13 male sports students. Each subject performed 3 valid trials for 3 starting distances: 0.3, 0.5, and 1.0 m from the initial timing lights, respectively. A high-speed video camera was used to track a reflective marker placed on the subjects' hip within a field of view around the initial timing gate. Accuracy of the initial timing gate was defined as the time between the initial timing light trigger and passing of the reflective marker by the initial timing gate. Sprint times were significantly faster for the 1.0-m starting distance (0.98 ± 0.06 seconds) than for the 0.5-m (1.05 ± 0.07 seconds) and the 0.3-m (1.09 ± 0.08 seconds) starting distances (p sprint times but not the accuracy of the initial timing gate. Researchers and coaches should consider the effect of starting distance on 5-m sprint time and ensure consistent testing protocols. Based on the results of this study, we recommend a starting distance of 0.3 m that should be used for all sprint performance tests.

  6. Do English and Mandarin Speakers Think about Time Differently?

    Science.gov (United States)

    Boroditsky, Lera; Fuhrman, Orly; McCormick, Kelly

    2011-01-01

    Time is a fundamental domain of experience. In this paper we ask whether aspects of language and culture affect how people think about this domain. Specifically, we consider whether English and Mandarin speakers think about time differently. We review all of the available evidence both for and against this hypothesis, and report new data that…

  7. Residence time determination for adsorbent beds of different configurations

    Energy Technology Data Exchange (ETDEWEB)

    Otermat, J.E.; Wikoff, W.O.; Kovach, J.L.

    1995-02-01

    The residence time calculations of ASME AG-1 Code, Section FC, currently specify a screen surface area method, that is technically incorrect. Test data has been obtained on Type II adsorber trays of different configurations to establish residence time in the adsorber trays. These data indicate that the air volume/carbon volume ratio or the average screen area are more appropriate for the calculation of the residence time calculation than the currently used, smallest screen area basis.

  8. ON GLOBAL ROBUST STABILITY FOR COMPETITIVE NEURAL NETWORKS WITH TIME DELAYS AND DIFFERENT TIME SCALES

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, using the theory of topological degree and Liapunov functional methods, the authors study the competitive neural networks with time delays and different time scales and present some criteria of global robust stability for this neural network model.

  9. A new method of time difference measurement: The time difference method by dual phase coincidence points detection

    Science.gov (United States)

    Zhou, Wei

    1993-01-01

    In the high accurate measurement of periodic signals, the greatest common factor frequency and its characteristics have special functions. A method of time difference measurement - the time difference method by dual 'phase coincidence points' detection is described. This method utilizes the characteristics of the greatest common factor frequency to measure time or phase difference between periodic signals. It can suit a very wide frequency range. Measurement precision and potential accuracy of several picoseconds were demonstrated with this new method. The instrument based on this method is very simple, and the demand for the common oscillator is low. This method and instrument can be used widely.

  10. Modelling financial markets with agents competing on different time scales and with different amount of information

    Science.gov (United States)

    Wohlmuth, Johannes; Andersen, Jørgen Vitting

    2006-05-01

    We use agent-based models to study the competition among investors who use trading strategies with different amount of information and with different time scales. We find that mixing agents that trade on the same time scale but with different amount of information has a stabilizing impact on the large and extreme fluctuations of the market. Traders with the most information are found to be more likely to arbitrage traders who use less information in the decision making. On the other hand, introducing investors who act on two different time scales has a destabilizing effect on the large and extreme price movements, increasing the volatility of the market. Closeness in time scale used in the decision making is found to facilitate the creation of local trends. The larger the overlap in commonly shared information the more the traders in a mixed system with different time scales are found to profit from the presence of traders acting at another time scale than themselves.

  11. ERP Indications for Sustained and Transient Auditory Spatial Attention with Different Lateralization Cues

    Science.gov (United States)

    Widmann, Andreas; Schröger, Erich

    The presented study was designed to investigate ERP effects of auditory spatial attention in sustained attention condition (where the to-be-attended location is defined in a blockwise manner) and in a transient attention condition (where the to-be-attended location is defined in a trial-by-trial manner). Lateralization in the azimuth plane was manipulated (a) via monaural presentation of l- and right-ear sounds, (b) via interaural intensity differences, (c) via interaural time differences, (d) via an artificial-head recording, and (e) via free-field stimulation. Ten participants were delivered with frequent Nogo- and infrequent Go-Stimuli. In one half of the experiment participants were instructed to press a button if they detected a Go-stimulus at a predefined side (sustained attention), in the other half they were required to detect Go-stimuli following an arrow-cue at the cued side (transient attention). Results revealed negative differences (Nd) between ERPs elicited by to-be-attended and to-be-ignored sounds in all conditions. These Nd-effects were larger for the sustained than for the transient attention condition indicating that attentional selection according to spatial criteria is improved when subjects can focus to one and the same location for a series of stimuli.

  12. A genetic basis for intraspecific differences in developmental timing?

    Science.gov (United States)

    Tills, Oliver; Rundle, Simon D; Salinger, Moritz; Haun, Timm; Pfenninger, Markus; Spicer, John I

    2011-01-01

    Heterochrony, altered developmental timing between ancestors and their descendents, has been proposed as a pervasive evolutionary feature and recent analytical approaches have confirmed its existence as an evolutionary pattern. Yet, the mechanistic basis for heterochrony remains unclear and, in particular, whether intraspecific variation in the timing of developmental events generates, or has the potential to generate, future between-species differences. Here we make a key step in linking heterochrony at the inter- and intraspecific level by reporting an association between interindividual variation in both the absolute and relative timing (position within the sequence of developmental events) of key embryonic developmental events and genetic distance for the pond snail, Radix balthica. We report significant differences in the genetic distance of individuals exhibiting different levels of dissimilarity in their absolute and relative timing of developmental events such as spinning activity, eyespot formation, heart ontogeny, and hatching. This relationship between genetic and developmental dissimilarity is consistent with there being a genetic basis for variation in developmental timing and so suggests that intraspecific heterochrony could provide the raw material for natural selection to produce speciation.

  13. EFFECT OF GENDER DIFFERENCE ON BRAKE REACTION TIME

    Directory of Open Access Journals (Sweden)

    Ashok

    2016-02-01

    Full Text Available BACKGROUND OF THE STUDY Reaction time is the time taken to respond to a stimulus or change in the environment. It is a method to assess the time taken from the perception of a stimulus followed by mental processing for a motor response. Reaction time in various day to day activities as in driving a car is very important. Brake reaction time (BRT is the time taken for the driver to respond to visualize an object and to press the brake pedal. It is affected by many features like age, gender, neuromuscular disorders. OBJECTIVE OF THE STUDY Study has been undertaken to compare the BRT in male and female drivers and to analyze the effect of sex difference on Brake reaction time. MATERIALS & METHODS Male and female subjects between the age group of 25 – 35 years with driving license were included. Study is conducted in a stationary car. An in-house built; braking timer is fixed to the electric circuit of the braking system in the car. This device is wirelessly connected to the reaction time software installed in the laptop. The subject is instructed to press the brake pedal when the light changed from red to green in the laptop screen. 5 readings are taken and the mean BRT is recorded. STATISTICAL ANALYSIS & RESULTS Statistical analysis done with unpaired student t test indicates that the BRT was more in the females than the males and was statistically significant (p value - 0007. CONCLUSION Gender difference has a significant effect on BRT and reaction time in female is longer than for the males.

  14. Time course of muscle soreness following different types of exercise

    Directory of Open Access Journals (Sweden)

    Vickers Andrew J

    2001-10-01

    Full Text Available Abstract Background Post-exercise muscle soreness is a dull, aching sensation that follows unaccustomed muscular exertion. Primarily on the basis of previous laboratory-based research on eccentric exercise, soreness is usually said to follow an inverted U-shaped curve over time, peaking 24 – 48 hours after exercise. As such, it is often described as "delayed-onset" muscle soreness. In a study of long-distance runners, soreness seemed to peak immediately and then reduce gradually over time. The study is a secondary analysis of clinical trial data that aims to determine whether the time course of soreness following a natural exercise, long-distance running, is different from that following a laboratory-based exercise, bench-stepping. Methods This is a reanalysis of data from three previous clinical trials. The trials included 400 runners taking part in long-distance races and 82 untrained volunteers performing a bench-stepping test. Subjects completed a Likert scale of muscle soreness every morning and evening for the five days following their exercise. Results Interaction between trial and time is highly significant, suggesting a different time course of soreness following running and bench-stepping. 45% of subjects in the bench-stepping trial experienced peak soreness at the third or fourth follow-up (approximately 36 – 48 hours after exercise compared to only 14% of those in the running trial. The difference between groups is robust to multivariate analysis incorporating possible confounding variables. Conclusion Soreness in runners following long-distance running follows a different time course to that in untrained individuals undertaking bench-stepping. Research on exercise taking place in the laboratory context does not necessarily generalize to exercise undertaken by trained athletes when engaged in their chosen sport.

  15. Time course of muscle soreness following different types of exercise

    Science.gov (United States)

    Vickers, Andrew J

    2001-01-01

    Background Post-exercise muscle soreness is a dull, aching sensation that follows unaccustomed muscular exertion. Primarily on the basis of previous laboratory-based research on eccentric exercise, soreness is usually said to follow an inverted U-shaped curve over time, peaking 24 – 48 hours after exercise. As such, it is often described as "delayed-onset" muscle soreness. In a study of long-distance runners, soreness seemed to peak immediately and then reduce gradually over time. The study is a secondary analysis of clinical trial data that aims to determine whether the time course of soreness following a natural exercise, long-distance running, is different from that following a laboratory-based exercise, bench-stepping. Methods This is a reanalysis of data from three previous clinical trials. The trials included 400 runners taking part in long-distance races and 82 untrained volunteers performing a bench-stepping test. Subjects completed a Likert scale of muscle soreness every morning and evening for the five days following their exercise. Results Interaction between trial and time is highly significant, suggesting a different time course of soreness following running and bench-stepping. 45% of subjects in the bench-stepping trial experienced peak soreness at the third or fourth follow-up (approximately 36 – 48 hours after exercise) compared to only 14% of those in the running trial. The difference between groups is robust to multivariate analysis incorporating possible confounding variables. Conclusion Soreness in runners following long-distance running follows a different time course to that in untrained individuals undertaking bench-stepping. Research on exercise taking place in the laboratory context does not necessarily generalize to exercise undertaken by trained athletes when engaged in their chosen sport. PMID:11701094

  16. On Cremonian Dimensions Qualitatively Different from Time and Space

    CERN Document Server

    Saniga, M

    2004-01-01

    We examine a particular kind of six-dimensional Cremonian universe featuring one dimension of space, three dimensions of time and other two dimensions that can*not* be ranked as either time or space. One of these two, generated by a one-parametric aggregate of (straight-)lines lying on a quadratic cone, is more similar to the spatial dimension. The other, represented by a singly-parametrical set of singular space quartic curves situated on a proper ruled quadric surface, bears more resemblance to time. Yet, the two dimensions differ profoundly from both time and space because, although being macroscopic, they are not accessible to (detectable by) every Cremonian observer. This toy-model thus demonstrates that there might exist extra-dimensions that need not necessarily be compactified to remain unobservable.

  17. Fractal markets: Liquidity and investors on different time horizons

    Science.gov (United States)

    Li, Da-Ye; Nishimura, Yusaku; Men, Ming

    2014-08-01

    In this paper, we propose a new agent-based model to study the source of liquidity and the “emergent” phenomenon in financial market with fractal structure. The model rests on fractal market hypothesis and agents with different time horizons of investments. What is interesting is that though the agent-based model reveals that the interaction between these heterogeneous agents affects the stability and liquidity of the financial market the real world market lacks detailed data to bring it to light since it is difficult to identify and distinguish the investors with different time horizons in the empirical approach. results show that in a relatively short period of time fractal market provides liquidity from investors with different horizons and the market gains stability when the market structure changes from uniformity to diversification. In the real world the fractal structure with the finite of horizons can only stabilize the market within limits. With the finite maximum horizons, the greater diversity of the investors and the fractal structure will not necessarily bring more stability to the market which might come with greater fluctuation in large time scale.

  18. Finite-difference time-domain analysis of time-resolved terahertz spectroscopy experiments

    DEFF Research Database (Denmark)

    Larsen, Casper; Cooke, David G.; Jepsen, Peter Uhd

    2011-01-01

    In this paper we report on the numerical analysis of a time-resolved terahertz (THz) spectroscopy experiment using a modified finite-difference time-domain method. Using this method, we show that ultrafast carrier dynamics can be extracted with a time resolution smaller than the duration of the THz...... probe pulse and can be determined solely by the pump pulse duration. Our method is found to reproduce complicated two-dimensional transient conductivity maps exceedingly well, demonstrating the power of the time-domain numerical method for extracting ultrafast and dynamic transport parameters from time...

  19. Gender differences in leisure-time versus non-leisure-time physical activity among Saudi adolescents

    Directory of Open Access Journals (Sweden)

    Hana Al-Sobayel

    2015-05-01

    The study showed that female adolescents are much less active than males, especially in leisure-time physical activities. Programmes to promote physical activity among adolescents are urgently needed, with consideration of gender differences.

  20. Start time delays in operating room: Different perspectives

    Directory of Open Access Journals (Sweden)

    Babita Gupta

    2011-01-01

    Full Text Available Background: Healthcare expenditure is a serious concern, with escalating costs failing to meet the expectations of quality care. The treatment capacities are limited in a hospital setting and the operating rooms (ORs. Their optimal utilization is vital in efficient hospital management. Starting late means considerable wait time for staff, patients and waste of resources. We planned an audit to assess different perspectives of the residents in surgical specialities and anesthesia and OR staff nurses so as to know the causative factors of operative delay. This can help develop a practical model to decrease start time delays in operating room (ORs. Aims: An audit to assess different perspectives of the Operating room (OR staff with respect to the varied causative factors of operative delay in the OR. To aid in the development of a practical model to decrease start time delays in ORs and facilitate on-time starts at Jai Prakash Narayan Apex Trauma centre (JPNATC, All India Institute of Medical Sciences (AIIMS, New Delhi. Methods: We prepared a questionnaire seeking the five main reasons of delay as per their perspective. Results: The available data was analysed. Analysis of the data demonstrated the common causative factors in start time operative delays as: a lack of proper planning, deficiencies in team work, communication gap and limited availability of trained supporting staff. Conclusions: The preparation of the equipment and required material for the OR cases must be done well in advance. Utilization of newer technology enables timely booking and scheduling of cases. Improved inter-departmental coordination and compliance with preanesthetic instructions needs to be ensured. It is essential that the anesthesiologists perform their work promptly, well in time . and supervise the proceedings as the OR manager. This audit is a step forward in defining the need of effective OR planning for continuous quality improvement.

  1. Overestimation of the second time interval replaces time-shrinking when the difference between two adjacent time intervals increases

    Directory of Open Access Journals (Sweden)

    Yoshitaka eNakajima

    2014-05-01

    Full Text Available When the onsets of three successive sound bursts mark two adjacent time intervals, the second time interval can be underestimated when it is physically longer than the first time interval by up to 100 ms. This illusion, time-shrinking, is very stable when the first time interval is 200 ms or shorter (Nakajima et al., 2004, Perception, 33. Time-shrinking had been considered a kind of perceptual assimilation to make the first and the second time interval more similar to each other. Here we investigated whether the underestimation of the second time interval was replaced by an overestimation if the physical difference between the neighboring time intervals was too large for the assimilation to take place; this was a typical situation in which a perceptual contrast could be expected. Three experiments to measure the overestimation/underestimation of the second time interval by the method of adjustment were conducted. The first time interval was varied from 40 to 280 ms, and such overestimations indeed took place when the first time interval was 80-280 ms. The overestimations were robust when the second time interval was longer than the first time interval by 240 ms or more, and the magnitude of the overestimation was larger than 100 ms in some conditions. Thus, a perceptual contrast to replace time-shrinking was established. An additional experiment indicated that this contrast did not affect the perception of the first time interval substantially: The contrast in the present conditions seemed unilateral.

  2. Time Perspective and Age: A Review of Age Associated Differences.

    Science.gov (United States)

    Laureiro-Martinez, Daniella; Trujillo, Carlos A; Unda, Juliana

    2017-01-01

    We investigate the relationship between age and the five dimensions of time perspective measured by the Zimbardo Time Perspective Inventory (ZTPI) (past negative, past positive, present hedonistic, present fatalistic, and future). Time perspective is related to well-being, decision-making, level of development, and many other psychological issues. Hence, the existence of a systematic relationship between time perspective and age should be considered in all studies for which time is a relevant variable. However, no specific research about this has been conducted. We collected 407 papers that referenced the ZTPI between 2001 and 2015. From those, 72 studies met our inclusion criteria. They included 29,815 participants from 19 countries whose age spans most phases of adulthood (from 13.5 to 75.5 years, mean 28.7). We analyzed these studies adapting meta-analytical techniques. We found that present hedonistic and past negative dimensions are negatively related to aging with partial eta squared effect sizes of roughly 0.15. Our results have implications for the design of studies related to time as our findings highlight the importance of taking into account the differences associated with age.

  3. Time Perspective and Age: A Review of Age Associated Differences

    Science.gov (United States)

    Laureiro-Martinez, Daniella; Trujillo, Carlos A.; Unda, Juliana

    2017-01-01

    We investigate the relationship between age and the five dimensions of time perspective measured by the Zimbardo Time Perspective Inventory (ZTPI) (past negative, past positive, present hedonistic, present fatalistic, and future). Time perspective is related to well-being, decision-making, level of development, and many other psychological issues. Hence, the existence of a systematic relationship between time perspective and age should be considered in all studies for which time is a relevant variable. However, no specific research about this has been conducted. We collected 407 papers that referenced the ZTPI between 2001 and 2015. From those, 72 studies met our inclusion criteria. They included 29,815 participants from 19 countries whose age spans most phases of adulthood (from 13.5 to 75.5 years, mean 28.7). We analyzed these studies adapting meta-analytical techniques. We found that present hedonistic and past negative dimensions are negatively related to aging with partial eta squared effect sizes of roughly 0.15. Our results have implications for the design of studies related to time as our findings highlight the importance of taking into account the differences associated with age. PMID:28261119

  4. Time trade-off: one methodology, different methods

    OpenAIRE

    Attema, Arthur; Edelaar-Peeters, Yvette; Versteegh, Matthijs; Stolk, Elly

    2013-01-01

    textabstractAbstract There is no scientific consensus on the optimal specification of the time trade-off (TTO) task. As a consequence, studies using TTO to value health states may share the core element of trading length of life for quality of life, but can differ considerably on many other elements. While this pluriformity in specifications advances the understanding of TTO from a methodological point of view, it also results in incomparable health state values. Health state values are appli...

  5. Test of High Time Resolution MRPC with Different Readout Modes

    CERN Document Server

    Yang, S; Li, C; Heng, Y K; Qian, S; Chen, H F; Chen, T X; Dai, H L; Fan, H H; Liu, S B; Liu, S D; Jiang, X S; Shao, M; Tang, Z B; Zhang, H; Zhao, Z G

    2014-01-01

    In order to further enhance the particle identification capability of the Beijing Spectrometer (BESIII), it is proposed to upgrade the current end-cap time-of-flight (eTOF) detector with multi-gap resistive plate chamber (MRPC). The prototypes, together with the front end electronics (FEE) and time digitizer (TDIG) module have been tested at the E3 line of Beijing Electron Positron Collider (BEPCII) to study the difference between the single and double-end readout MRPC designs. The time resolutions (sigma) of the single-end readout MRPC are 47/53 ps obtained by 600 MeV/c proton/pion beam, while that of the double-end readout MRPC is 40 ps (proton beam). The efficiencies of three MRPC modules tested by both proton and pion beam are better than 98%. For the double-end readout MRPC, no incident position dependence is observed.

  6. Cognitive componets of speech at different time scales

    DEFF Research Database (Denmark)

    Feng, Ling; Hansen, Lars Kai

    2007-01-01

    Cognitive component analysis (COCA) is defined as unsupervised grouping of data leading to a group structure well aligned with that resulting from human cognitive activity. We focus here on speech at different time scales looking for possible hidden ‘cognitive structure’. Statistical regularities......, assumed to model the basic representation of the human auditory system. The basic features are aggregated in time to obtain features at longer time scales. Simple energy based filtering is used to achieve a sparse representation. Our hypothesis is now basically ecological: We hypothesize that features...... that are essentially independent in a reasonable ensemble can be efficiently coded using a sparse independent component representation. The representations are indeed shown to be very similar between supervised learning (invoking cognitive activity) and unsupervised learning (statistical regularities), hence lending...

  7. Individual differences in time perspective predict autonoetic experience.

    Science.gov (United States)

    Arnold, Kathleen M; McDermott, Kathleen B; Szpunar, Karl K

    2011-09-01

    Tulving (1985) posited that the capacity to remember is one facet of a more general capacity-autonoetic (self-knowing) consciousness. Autonoetic consciousness was proposed to underlie the ability for "mental time travel" both into the past (remembering) and into the future to envision potential future episodes (episodic future thinking). The current study examines whether individual differences can predict autonoetic experience. Specifically, the Zimbardo Time Perspective Inventory (ZTPI, Zimbardo & Boyd, 1999) was administered to 133 undergraduate students, who also rated phenomenological experiences accompanying autobiographical remembering and episodic future thinking. Scores on two of the five subscales of the ZTPI (Future and Present-Hedonistic) predicted the degree to which people reported feelings of mentally traveling backward (or forward) in time and the degree to which they reported re- or pre-experiencing the event, but not ten other rated properties less related to autonoetic consciousness.

  8. Modelling of UV radiation variations at different time scales

    Directory of Open Access Journals (Sweden)

    J. L. Borkowski

    2008-03-01

    Full Text Available Solar UV radiation variability in the period 1976–2006 is discussed with respect to the relative changes in the solar global radiation, ozone content, and cloudiness. All the variables were decomposed into separate components, representing variations of different time scales, using wavelet multi-resolution decomposition. The response of the UV radiation to the changes in the solar global radiation, ozone content, and cloudiness depends on the time scale, therefore, it seems reasonable to model separately the relation between UV and explanatory variables at different time scales. The wavelet components of the UV series are modelled and summed to obtain the fit of observed series. The results show that the coarser time scale components can be modelled with greater accuracy than fine scale components and the fitted values calculated by this method are in better agreement with observed values than values calculated by the regression method, in which variables were not decomposed. The residual standard error in the case of modelling with the use of wavelets is reduced by 14% in comparison to the regression method without decomposition.

  9. Perceiving Time Differences When You Should Not: Applying the El Greco Fallacy to Hypnotic Time Distortions

    Science.gov (United States)

    Martin, Jean-Rémy; Sackur, Jérôme; Anlló, Hernan; Naish, Peter; Dienes, Zoltan

    2016-01-01

    The way we experience and estimate time – subjective time – does not systematically correspond to objective time (the physical duration of an event). Many factors can influence subjective time and lead to mental dilation or compression of objective time. The emotional valence of stimuli or the levels of attention or expectancy are known to modulate subjective time even though objective time is constant. Hypnosis too is known to alter people’s perception of time. However, it is not known whether hypnotic time distortions are intrinsic perceptual effects, based for example on the changing rate of an internal clock, or rather the result of a response to demand characteristics. Here we distinguished the theories using the logic of the El Greco fallacy. When participants initially had to compare the duration of two successive events —with the same duration — while in “trance,” they responded that the second event was on average longer than the first event. As both events were estimated in “trance,” if hypnosis had impacted on an internal clock, they should have been affected to the same extent. Conversely, when only the first event was in “trance,” there was no difference in perceived duration. The findings conform to an El Greco fallacy effect and challenge theories of hypnotic time distortion arguing that “trance” itself changes subjective time. PMID:27625623

  10. Perceiving Time Differences When You Should Not: Applying the El Greco Fallacy to Hypnotic Time Distortions.

    Science.gov (United States)

    Martin, Jean-Rémy; Sackur, Jérôme; Anlló, Hernan; Naish, Peter; Dienes, Zoltan

    2016-01-01

    The way we experience and estimate time - subjective time - does not systematically correspond to objective time (the physical duration of an event). Many factors can influence subjective time and lead to mental dilation or compression of objective time. The emotional valence of stimuli or the levels of attention or expectancy are known to modulate subjective time even though objective time is constant. Hypnosis too is known to alter people's perception of time. However, it is not known whether hypnotic time distortions are intrinsic perceptual effects, based for example on the changing rate of an internal clock, or rather the result of a response to demand characteristics. Here we distinguished the theories using the logic of the El Greco fallacy. When participants initially had to compare the duration of two successive events -with the same duration - while in "trance," they responded that the second event was on average longer than the first event. As both events were estimated in "trance," if hypnosis had impacted on an internal clock, they should have been affected to the same extent. Conversely, when only the first event was in "trance," there was no difference in perceived duration. The findings conform to an El Greco fallacy effect and challenge theories of hypnotic time distortion arguing that "trance" itself changes subjective time.

  11. Perceiving time differences when you should not: Applying the El Greco fallacy to hypnotic time distortions

    Directory of Open Access Journals (Sweden)

    Jean-Rémy Martin

    2016-08-01

    Full Text Available The way we experience and estimate time – subjective time – does not systematically correspond to objective time (the physical duration of an event. Many factors can influence subjective time and lead to mental dilation or compression of objective time. The emotional valence of stimuli or the level of attention or expectancy are known to modulate subjective time although objective time is constant. Hypnosis too is known to alter people’s perception of time. However, it is not known whether hypnotic time distortions are intrinsic perceptual effects, based for example on the changing rate of an internal clock, or rather the result of a response to demand characteristics. Here we distinguished the theories using the logic of the El Greco fallacy. When participants initially had to compare the duration of two successive events —with the same duration — while in trance, they responded that the second event was on average longer than the first event. As both events were estimated in trance, if hypnosis impacted an internal clock, they should have been affected to the same extent. Conversely, when only the first event was in trance, there was no difference in perceived duration. The findings conform to an El Greco fallacy effect and challenge theories of hypnotic time distortion arguing that trance itself changes subjective time.

  12. Milk oligosaccharides over time of lactation from different dog breeds.

    Directory of Open Access Journals (Sweden)

    Shirin Macias Rostami

    Full Text Available The partnership of humans and dogs goes back to over 10'000 years, yet relatively little is known about a dog's first extra-uterine nutrition particularly when it comes to milk oligosaccharides. We set out to identify and quantify milk oligosaccharides over the course of lactation from different dog breeds (Labrador retriever, Schnauzer and 3 Alaskan husky crossbreeds. To this end, 2 different chromatographic methods with fluorescence and mass spectrometry detection were developed and one was validated for quantification. Besides lactose and lactose-sulphate, we identified 2 different trisaccharides composed of 3 hexose units, 3'sialyllactose (3'SL, 6'sialyllactose (6'SL, 2'fucosyllactose (2'FL, and a tetrasaccharide composed of 2 hexoses, an N-acetylhexosamine and a deoxyhexose. 3'SL was present at the highest levels in milk of all dog breeds starting at around 7.5 g/L and dropping to about 1.5 g/L in the first 10 days of lactation. 6'SL was about 10 times less abundant and 2'FL and the tetrasaccharide had rather varying levels in the milk of the different breeds with the tetrasaccharide only detectable in the Alaskan husky crossbreeds. The longitudinal and quantitative data of milk oligosaccharides from different dog breeds are an important basis to further our understanding on their specific biological roles and also on the specific nutritional requirements of lactating puppies.

  13. Variation of explosive force at different times of day

    Directory of Open Access Journals (Sweden)

    R Pereira

    2011-03-01

    Full Text Available AIM: The purpose of this study was to compare the explosive force and electromyographic (EMG activity at three different times of the day. METHODS: Thirty healthy subjects took part in the study, and carried out two maximum isometric voluntary knee extensions to measure explosive force, through contractile impulse (CI and rate of force development (RFD, and myoelectric signals from quadriceps muscles in the following periods: 07:30-09:30, 13:30-15:30 and 19:30-21:30 (called morning, afternoon and night respectively, on three non-consecutive days. RESULTS: The body temperature was lower in the morning than in the afternoon and night periods. The explosive force, evaluated through contractile impulse (CI and rate of force development (RFD, was greater at night than in the morning, without differences in the myoelectric signal. CONCLUSION: The ability to produce explosive force varies throughout different times of the day without variation in muscular recruitment, indicating that peripheral and not neural mechanisms could be responsible for this variation.

  14. Coincidence-anticipation timing requirements are different in racket sports.

    Science.gov (United States)

    Akpinar, Selçuk; Devrilmez, Erhan; Kirazci, Sadettin

    2012-10-01

    The aim of this study was to compare the coincidence-anticipation timing accuracy of athletes of different racket sports with various stimulus velocity requirements. Ninety players (15 girls, 15 boys for each sport) from tennis (M age = 12.4 yr., SD = 1.4), badminton (M age = 12.5 yr., SD = 1.4), and table tennis (M age = 12.4 yr., SD = 1.2) participated in this study. Three different stimulus velocities, low, moderate, and high, were used to simulate the velocity requirements of these racket sports. Tennis players had higher accuracy when they performed under the low stimulus velocity compared to badminton and table tennis players. Badminton players performed better under the moderate speed comparing to tennis and table tennis players. Table tennis players had better performance than tennis and badminton players under the high stimulus velocity. Therefore, visual and motor systems of players from different racket sports may adapt to a stimulus velocity in coincidence-anticipation timing, which is specific to each type of racket sports.

  15. Perihematoma Damage at Different Time Points in Experimental Intracerebral Hemorrhage

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The damage degree of neurons in perilesion at different time points was observed in order to explore the optimal operation occasion. Piglet lobar hematomas were produced by pressure-controlled infusions of 2.5 mL autonomous blood into the right frontal hemispheric white matter over 15 min, and the metabolic changes were ambulatorily detected with MRS at 3rd, 12th, 24th and 48th h after hematoma induction. Brain tissues of perihematoma were also obtained at different time points. The transcription level of Bax gene was detected by in situ hybridization and apoptosis by TUNEL technique, and the pathologic change of neurons was observed under an electron microscope. The results showed that the number of Bax positive cells reached the peak at 24 h (79.00±4. 243/5 fields). There was no significant difference in A values between 3 h and 6 h, 12 h (P>0.05), but there significant difference between 24 h and 3 h, 6 h, 12 h (P<0.05). The number of apoptotic cells reached the peak at 24 h (P<0. 001), and there was no significant difference betw een 3 h and 6 h (P=0. 999). The area of the apoptotic cells showed no significant difference between 3 h and 6 h or among 3 h, 6 h and 6 h (P>0.05). Lac peak mainly occurred at 24 h and 48 h, while on the healthy side, no Lac peak was detectable. The ratio of NAA/Cr presented a descent tendency, but there was no significant difference among the groups before 12 h (P>0.05), there was very significant difference between 3, 6 and 24, 48 h (P<0.01). Under electronic microscopy, the neuronal damage surrounding hematoma in 3 to 6 h was milder than in 24 h to 48 h. It was concluded that the secondary apoptosis, damage and metabolic disturbance of the neurons surround ing hematoma was milder in 3-6 h in acute intracerebral hemorrhage, while obviously aggravated in 24-48 h. An effective intervention is needed to reduce secondary damage as soon as possible.

  16. Acoustic radiation force analysis using finite difference time domain method.

    Science.gov (United States)

    Grinenko, A; Wilcox, P D; Courtney, C R P; Drinkwater, B W

    2012-05-01

    Acoustic radiation force exerted by standing waves on particles is analyzed using a finite difference time domain Lagrangian method. This method allows the acoustic radiation force to be obtained directly from the solution of nonlinear fluid equations, without any assumptions on size or geometry of the particles, boundary conditions, or acoustic field amplitude. The model converges to analytical results in the limit of small particle radii and low field amplitudes, where assumptions within the analytical models apply. Good agreement with analytical and numerical models based on solutions of linear scattering problems is observed for compressible particles, whereas some disagreement is detected when the compressibility of the particles decreases.

  17. Time, science and consensus: the different times involving scientific research, political decision and public opinion

    OpenAIRE

    José Aparecido; Isaac Epstein

    2010-01-01

    This essay analyses the asymmetrical relationship between the time of scientific research and the time of the different segments interested in their results, focusing mainly on necessity to establish technical consensus about the fields of science that require rigorous investigations and texts. In the last years, civil society sectors - mainly scientific journalism, legislative power, and public opinion - has shown growing interest in participating of the decision making process that regulate...

  18. Diurnal Differences in OLR Climatologies and Anomaly Time Series

    Science.gov (United States)

    Susskind, Joel; Lee, Jae N.; Iredell, Lena; Loeb, Norm

    2015-01-01

    AIRS (Atmospheric Infrared Sounder) Version-6 OLR (Outgoing Long-Wave Radiation) matches CERES (Clouds and the Earth's Radiant Energy System) Edition-2.8 OLR very closely on a 1x1 latitude x longitude scale, both with regard to absolute values, and also with regard to anomalies of OLR. There is a bias of 3.5 watts per meter squared, which is nearly constant both in time and space. Contiguous areas contain large positive or negative OLR difference between AIRS and CERES are where the day-night difference of OLR is large. For AIRS, the larger the diurnal cycle, the more likely that sampling twice a day is inadequate. Lower values of OLRclr (Clear Sky OLR) and LWCRF (Longwave Cloud Radiative Forcing) in AIRS compared to CERES is at least in part a result of AIRS sampling over cold and cloudy cases.

  19. Decomposition of wind speed fluctuations at different time scales

    Indian Academy of Sciences (India)

    Qinmin Zheng; S Rehman; Md Mahbub Alam; L M Alhems; A Lashin

    2017-04-01

    Understanding the inherent features of wind speed (variability on different time scales) has become critical for assured wind power availability, grid stability, and effective power management. The study utilizes the wavelet, autocorrelation, and FFT (fast Fourier transform) techniques to analyze and assimilate the fluctuating nature of wind speed data collected over a period of 29–42 years at different locations in the Kingdom of Saudi Arabia. The analyses extracted the intrinsic features of wind speed, including the long-term mean wind speed and fluctuations at different time scales (periods), which is critical for meteorological purposes including wind power resource assessment and weather forecasting. The longterm mean wind speed varied between 1.45 m/s at Mecca station and 3.73 m/s at Taif. The annual variation is the largest (±0.97 m/s) at Taif and the smallest (±0.25 m/s) at Mecca. Similarly, the wind speed fluctuation with different periods was also discussed in detail. The spectral characteristics obtained using FFT reveal that Al-Baha, Najran, Taif and Wadi-Al-Dawasser having a sharp peak at a frequency f = 0.00269 (1/day) retain a more regular annual repetition of wind speed than Bisha, Khamis-Mushait, Madinah, Mecca, and Sharourah. Based on the autocorrelation analysis and FFT results, the stations are divided into three groups: (i) having strong annual modulations (Al-Baha, Najran, Taif and Wadi-Al-Dawasser), (ii) having comparable annual and half-yearly modulations (Bisha, Khamis-Mushait, and Mecca) and (iii) having annual modulation moderately prominent (Madinah and Sharourah).

  20. Overcoming the Educational Time Warp: Anticipating a Different Future

    Directory of Open Access Journals (Sweden)

    Garry Jacobs

    2015-10-01

    Full Text Available Education abridges the time required for individual and social progress by preserving and propagating the essence of human experience. It delivers to youth the accumulated knowledge of countless past generations in an organized and abridged form, so that future generations can start off with all the capacities acquired by their predecessors. However, today education confronts a serious dilemma. We are living in an educational time warp. There is a growing gap between contemporary human experience and what is taught in our educational system and that gap is widening rapidly with each passing year. Today humanity confronts challenges of unprecedented scope, magnitude and intensity. The incremental development of educational content and pedagogy in recent decades has not kept with the ever-accelerating pace of technological and social evolution. Education is also subject to a generational time warp resulting from the fact that many of today’s teachers were educated decades ago during very different times and based on different values and perspectives. The challenge of preparing youth for the future is exasperated by the fact that the future for which we are educating youth does not yet exist and to a large extent is unknown or unknowable. The resulting gap between the content of education and societal needs inhibits our capacity to anticipate and effectively respond to social problems. All these factors argue for a major reorientation of educational content and pedagogy from transmission of acquired knowledge based on past experience to development of the knowledge, skills and capacities of personality needed in a future we cannot clearly envision. We may not be able to anticipate the precise nature of the future, but we can provide an education based on the understanding that it will be very different from the present. In terms of content, the emphasis needs to shift from facts regarding the actual state of affairs in the past, present and

  1. Is networking different with doctors working part-time? Differences in social networks of part-time and full-time doctors.

    NARCIS (Netherlands)

    Heiligers, P.J.M.; Groenewegen, P.P.; Jong, J.D. de; Hingstman, L.; Völker, B.; Spreeuwenberg, P.

    2008-01-01

    BACKGROUND: Part-time working is a growing phenomenon in medicine, which is expected to influence informal networks at work differently compared to full-time working. The opportunity to meet and build up social capital at work has offered a basis for theoretical arguments. METHODS: Twenty-eight team

  2. Is networking different with doctors working part-time? : Differences in social networks of part-time and full-time doctors

    NARCIS (Netherlands)

    Heiligers, Phil J.M.; Jong, Judith D. de; Groenewegen, Peter P.; Hingstman, Lammert; Völker, Beate; Spreeuwenberg, Peter

    2008-01-01

    Background: Part-time working is a growing phenomenon in medicine, which is expected to influence informal networks at work differently compared to full-time working. The opportunity to meet and build up social capital at work has offered a basis for theoretical arguments. Methods: Twenty-eight team

  3. HOW DIFFERENT VARIABLES AFFECT THE ACCURACY OF HAND-TIMING

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To analyze the process of hand-timing and the resulting data collected from the hand-timing computer system(HTCS),including the timing operator′s reaction times of starting and stopping the watch,the results from the timing,the simulated electronic timing,the major factor that affects the time-keeper′s accuracy of time-keeping were studied,i.e.the stability of the time-keeper′s reaction time,rather than the time-keeper′s reation time.The leading cause that inflicts error between the hand-time-keeping and the electrionic time-keeping consists in the pitfall that the time-keeper makes a wrong judgment in stopping the watch.The analytical results provide theoretic gist for the selection and training of time-keeping operators.

  4. Time, science and consensus: the different times involving scientific research, political decision and public opinion

    Directory of Open Access Journals (Sweden)

    José Aparecido de

    2010-01-01

    Full Text Available This essay analyses the asymmetrical relationship between the time of scientific research and the time of the different segments interested in their results, focusing mainly on necessity to establish technical consensus about the fields of science that require rigorous investigations and texts. In the last years, civil society sectors - mainly scientific journalism, legislative power, and public opinion - has shown growing interest in participating of the decision making process that regulates science routes. In this study, we analyzed the decision making process of the Biosafety Law, as it allows research with embryonic stem cells in Brazil. The results allow us to conclude that this asymmetrical relationship between the different times (of science, scientific disclosure, public opinion, and public power contribute to the maturing of the dialog on scientific policies, as well as to the establishment of a consensus concerning science routes, which aims at the democratization of scientific work.

  5. Trading people versus trading time: What is the difference?

    Directory of Open Access Journals (Sweden)

    Goldstein Christine C

    2005-11-01

    Full Text Available Abstract Background Person trade-off (PTO elicitations yield different values than standard utility measures, such as time trade-off (TTO elicitations. Some people believe this difference arises because the PTO captures the importance of distributive principles other than maximizing treatment benefits. We conducted a qualitative study to determine whether people mention considerations related to distributive principles other than QALY-maximization more often in PTO elicitations than in TTO elicitations and whether this could account for the empirical differences. Methods 64 members of the general public were randomized to one of three different face-to-face interviews, thinking aloud as they responded to TTO and PTO elicitations. Participants responded to a TTO followed by a PTO elicitation within contexts that compared either: 1 two life-saving treatments; 2 two cure treatments; or 3 a life-saving treatment versus a cure treatment. Results When people were asked to choose between life-saving treatments, non-maximizing principles were more common with the PTO than the TTO task. Only 5% of participants considered non-maximizing principles as they responded to the TTO elicitation compared to 68% of participants who did so when responding to the PTO elicitation. Non-maximizing principles that emerged included importance of equality of life and a desire to avoid discrimination. However, these principles were less common in the other two contexts. Regardless of context, though, participants were significantly more likely to respond from a societal perspective with the PTO compared to the TTO elicitation. Conclusion When lives are at stake, within the context of a PTO elicitation, people are more likely to consider non-maximizing principles, including the importance of equal access to a life-saving treatment, avoiding prejudice or discrimination, and in rare cases giving treatment priority based purely on the position of being worse-off.

  6. Computational electrodynamics the finite-difference time-domain method

    CERN Document Server

    Taflove, Allen

    2005-01-01

    This extensively revised and expanded third edition of the Artech House bestseller, Computational Electrodynamics: The Finite-Difference Time-Domain Method, offers engineers the most up-to-date and definitive resource on this critical method for solving Maxwell's equations. The method helps practitioners design antennas, wireless communications devices, high-speed digital and microwave circuits, and integrated optical devices with unsurpassed efficiency. There has been considerable advancement in FDTD computational technology over the past few years, and the third edition brings professionals the very latest details with entirely new chapters on important techniques, major updates on key topics, and new discussions on emerging areas such as nanophotonics. What's more, to supplement the third edition, the authors have created a Web site with solutions to problems, downloadable graphics and videos, and updates, making this new edition the ideal textbook on the subject as well.

  7. Accurate finite difference methods for time-harmonic wave propagation

    Science.gov (United States)

    Harari, Isaac; Turkel, Eli

    1994-01-01

    Finite difference methods for solving problems of time-harmonic acoustics are developed and analyzed. Multidimensional inhomogeneous problems with variable, possibly discontinuous, coefficients are considered, accounting for the effects of employing nonuniform grids. A weighted-average representation is less sensitive to transition in wave resolution (due to variable wave numbers or nonuniform grids) than the standard pointwise representation. Further enhancement in method performance is obtained by basing the stencils on generalizations of Pade approximation, or generalized definitions of the derivative, reducing spurious dispersion, anisotropy and reflection, and by improving the representation of source terms. The resulting schemes have fourth-order accurate local truncation error on uniform grids and third order in the nonuniform case. Guidelines for discretization pertaining to grid orientation and resolution are presented.

  8. Parallel finite-difference time-domain method

    CERN Document Server

    Yu, Wenhua

    2006-01-01

    The finite-difference time-domain (FTDT) method has revolutionized antenna design and electromagnetics engineering. This book raises the FDTD method to the next level by empowering it with the vast capabilities of parallel computing. It shows engineers how to exploit the natural parallel properties of FDTD to improve the existing FDTD method and to efficiently solve more complex and large problem sets. Professionals learn how to apply open source software to develop parallel software and hardware to run FDTD in parallel for their projects. The book features hands-on examples that illustrate the power of parallel FDTD and presents practical strategies for carrying out parallel FDTD. This detailed resource provides instructions on downloading, installing, and setting up the required open source software on either Windows or Linux systems, and includes a handy tutorial on parallel programming.

  9. Different Types of Synchronization in Time-Delayed Systems

    Institute of Scientific and Technical Information of China (English)

    FENG Cun-Fang; ZHANG Yan; WANG Ying-Hai

    2007-01-01

    @@ We investigate different types of synchronization between two unidirectionally nonlinearly coupled identical delaydifferential systems related to optical bistable or hybrid optical bistable devices. This system can represent some kinds of delay-differential models, I.e. Ikeda model, Vallée model, sine-square model, Mackey-Glass model, and so on. We find existence and sufficient stability conditions by theoretical analysis and test the correctness by numerical simulations. Lag, complete and anticipating synchronization are observed, respectively. It is found that the time-delay system can be divided into two parts, one is the instant term and the other is the delay term.Synchronization between two identical chaotic systems can be derived by adding a coupled term to the delay term in the driven system.

  10. Variation of atmospheric depth profile on different time scales

    CERN Document Server

    Wilczynska, B; Homola, P; Pekala, J; Risse, M; Wilczynski, H

    2006-01-01

    The vertical profile of atmospheric depth is an important element in extensive air shower studies. The depth of shower maximum is one of the most important characteristics of the shower. In the fluorescence technique of shower detection, the geometrical reconstruction provides the altitude of shower maximum, so that an accurate profile of atmospheric depth is needed to convert this altitude to the depth of shower maximum. In this paper the temporal variation of experimentally measured profiles of atmospheric depth at different sites is studied and implications for shower reconstruction are shown. The atmospheric profiles vary on time scales from hours to years. It is shown that the daily variation of the profile is as important as its seasonal variation and should be accounted for in air shower studies. For precise shower reconstruction, the daily profiles determined locally at the site of the air shower detector are recommended.

  11. Reflections on the different sides of idleness in contemporary times

    Directory of Open Access Journals (Sweden)

    Patrícia Zaczuk Bassinello

    2015-04-01

    Full Text Available Over the last century, idleness experienced a modernization and democratization process especially with the crisis of a society focused on work – the post-Industrial Revolution - and the emergence of new ideas that put the free time, the leisure and recreation in the role of structural elements of the new social context and like tools for the new ways of life. In this work, we we seek to focus on the significant aspects of reality and function of leisure in our time, clarifying their relationship with the processes of personal, social and economic innovation by establishing a balance of our acts in thinking the leisure and work and leisure and life from different angles of approach. In order to analyze this phenomenon, we were based on scientific sources which are representative in the context, and then we elaborated a general overview of the subject from the contributions of the bakhtinian perspectives. We observed that the increase in leisure options in the last decades of the twentieth century, along with the growth of the studies of the idleness phenomenon and its possibilities, allowed an evolution of its concepts, from activities or practices associated to the consumption and to digital entertainment, to its understanding as an experience whose key of the discussion is the subject living these experiences. We believe that this reflection about idleness may open possibilities of a better comprehension of its insertion in the social and human sciences field and, especially, in its contribution to a new attitude of the relational production, centered on the subject, which stimulates a society that creates and innovates goods and services and who deepens the studies of leisure from the dynamic experiential horizon to the right to the otherness and to its time – the own one and the others’ – such as "the right to unfunctionality", from listening to the other word.

  12. Membrane bioreactor sludge rheology at different solid retention times.

    Science.gov (United States)

    Laera, G; Giordano, C; Pollice, A; Saturno, D; Mininni, G

    2007-10-01

    Rheological characterization is of crucial importance in sludge management both in terms of biomass dewatering and stabilization properties and in terms of design parameters for sludge handling operations. The sludge retention time (SRT) has a significant influence on biomass properties in biological wastewater treatment systems and in particular in membrane bioreactors (MBRs). The aim of this work is to compare the rheological behaviour of the biomass in a MBR operated under different SRTs. A bench-scale MBR was operated for 4 years under the same conditions except for the SRT, which ranged from 20 days to complete sludge retention. The rheological properties were measured over time and the apparent viscosity was correlated with the concentration of solid material when equilibrium conditions were reached and maintained. The three models most commonly adopted for rheological simulations were evaluated and compared in terms of their parameters. Then, steady-state average values of these parameters were related to the equilibrium biomass concentration (MLSS). The models were tested to select the one better fitting the experimental data in terms of mean root square error (MRSE). The relationship between the apparent viscosity and the shear rate, as a function of solid concentration, was determined and is proposed here. Statistical analysis showed that, in general, the Bingham model provided slightly better results than the Ostwald one. However, considering that a strong correlation between the two parameters of the Ostwald model was found for all the SRTs tested, both in the transient growth phases and under steady-state conditions, this model might be used more conveniently. This feature suggests that the latter model is easier to be used for the determination of the sludge apparent viscosity.

  13. Time trade-off: one methodology, different methods.

    Science.gov (United States)

    Attema, Arthur E; Edelaar-Peeters, Yvette; Versteegh, Matthijs M; Stolk, Elly A

    2013-07-01

    There is no scientific consensus on the optimal specification of the time trade-off (TTO) task. As a consequence, studies using TTO to value health states may share the core element of trading length of life for quality of life, but can differ considerably on many other elements. While this pluriformity in specifications advances the understanding of TTO from a methodological point of view, it also results in incomparable health state values. Health state values are applied in health technology assessments, and in that context comparability of information is desired. In this article, we discuss several alternative specifications of TTO presented in the literature. The defining elements of these specifications are identified as being either methodological, procedural or analytical in nature. Where possible, it is indicated how these elements affect health state values (i.e., upward or downward). Finally, a checklist for TTO studies is presented, which incorporates a list of choices to be made by researchers who wish to perform a TTO task. Such a checklist enables other researchers to align methodologies in order to enhance the comparability of health state values.

  14. Detecting abrupt climate changes on different time scales

    Science.gov (United States)

    Matyasovszky, István

    2011-10-01

    Two concepts are introduced for detecting abrupt climate changes. In the first case, the sampling frequency of climate data is high as compared to the frequency of climate events examined. The method is based on a separation of trend and noise in the data and is applicable to any dataset that satisfies some mild smoothness and statistical dependence conditions for the trend and the noise, respectively. We say that an abrupt change occurs when the first derivative of the trend function has a discontinuity and the task is to identify such points. The technique is applied to Northern Hemisphere temperature data from 1850 to 2009, Northern Hemisphere temperature data from proxy data, a.d. 200-1995 and Holocene δ18O values going back to 11,700 years BP. Several abrupt changes are detected that are, among other things, beneficial for determining the Medieval Warm Period, Little Ice Age and Holocene Climate Optimum. In the second case, the sampling frequency is low relative to the frequency of climate events studied. A typical example includes Dansgaard-Oeschger events. The methodology used here is based on a refinement of autoregressive conditional heteroscedastic models. The key element of this approach is the volatility that characterises the time-varying variance, and abrupt changes are defined by high volatilities. The technique applied to δ18O values going back to 122,950 years BP is suitable for identifying DO events. These two approaches for the two cases are closely related despite the fact that at first glance, they seem quite different.

  15. Is networking different with doctors working part-time? Differences in social networks of part-time and full-time doctors

    Directory of Open Access Journals (Sweden)

    Hingstman Lammert

    2008-10-01

    Full Text Available Abstract Background Part-time working is a growing phenomenon in medicine, which is expected to influence informal networks at work differently compared to full-time working. The opportunity to meet and build up social capital at work has offered a basis for theoretical arguments. Methods Twenty-eight teams of medical specialists in the Netherlands, including 226 individuals participated in this study. Interviews with team representatives and individual questionnaires were used. Data were gathered on three types of networks: relationships of consulting, communication and trust. For analyses, network and multilevel applications were used. Differences between individual doctors and between teams were both analysed, taking the dependency structure of the data into account, because networks of individual doctors are not independent. Teams were divided into teams with and without doctors working part-time. Results and Discussion Contrary to expectations we found no impact of part-time working on the size of personal networks, neither at the individual nor at the team level. The same was found regarding efficient reachability. Whereas we expected part-time doctors to choose their relations as efficiently as possible, we even found the opposite in intended relationships of trust, implying that efficiency in reaching each other was higher for full-time doctors. But we found as expected that in mixed teams with part-time doctors the frequency of regular communication was less compared to full-time teams. Furthermore, as expected the strength of the intended relationships of trust of part-time and full-time doctors was equally high. Conclusion From these findings we can conclude that part-time doctors are not aiming at efficiency by limiting the size of networks or by efficient reachability, because they want to contact their colleagues directly in order to prevent from communication errors. On the other hand, together with the growth of teams, we found

  16. The different time courses of reading different levels of Chinese characters: an ERP study.

    Science.gov (United States)

    Lu, Qilin; Tang, Yi-Yuan; Zhou, Li; Yu, Qingbao

    2011-07-12

    The dual route processing was generally accepted in the reading of alphabetic languages, which suggests alphabetic words can be read by either addressed pathway or assembled pathway. However, it was still unclear whether there was a particular 'dual route mechanism' during reading Chinese characters. In our previous fMRI study, the result showed that there might be a particular 'dual route mechanism', and its addressed pathway was similar between Chinese and English, whereas for the need of spatial analysis, the assembled pathway of Chinese was different from that of English which involved grapheme-to-phoneme correspondences. The present study, using event-related potential, which provide more temporal information, aimed to further support our previous view, and peered inside the different time courses of reading different types of Chinese characters. It was found that reading high frequency Chinese characters increased the N170 component which was believed to enhance attention to the addressed pathway in the left occipital-temporal area. Pseudo Chinese characters could be read by a particular assembled pathway, which caused the largest amplitude of P320 component in the right occipital-temporal area, which considered as a key brain area for radical analysis. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  17. The limit order book on different time scales

    CERN Document Server

    Eisler, Zoltan; Lillo, Fabrizio

    2007-01-01

    Financial markets can be described on several time scales. We use data from the limit order book of the London Stock Exchange (LSE) to compare how the fluctuation dominated microstructure crosses over to a more systematic global behavior.

  18. The limit order book on different time scales

    Science.gov (United States)

    Eisler, Zoltán; Kertész, János; Lillo, Fabrizio

    2007-06-01

    Financial markets can be described on several time scales. We use data from the limit order book of the London Stock Exchange (LSE) to compare how the fluctuation dominated microstructure crosses over to a more systematic global behavior.

  19. Individual Differences in Impulsive Choice and Timing in Rats

    Science.gov (United States)

    Galtress, Tiffany; Garcia, Ana; Kirkpatrick, Kimberly

    2012-01-01

    Individual differences in impulsive choice behavior have been linked to a variety of behavioral problems including substance abuse, smoking, gambling, and poor financial decision-making. Given the potential importance of individual differences in impulsive choice as a predictor of behavioral problems, the present study sought to measure the extent…

  20. Time-dependent optimal heater control using finite difference method

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhen Zhe; Heo, Kwang Su; Choi, Jun Hoo; Seol, Seoung Yun [Chonnam National Univ., Gwangju (Korea, Republic of)

    2008-07-01

    Thermoforming is one of the most versatile and economical process to produce polymer products. The drawback of thermoforming is difficult to control thickness of final products. Temperature distribution affects the thickness distribution of final products, but temperature difference between surface and center of sheet is difficult to decrease because of low thermal conductivity of ABS material. In order to decrease temperature difference between surface and center, heating profile must be expressed as exponential function form. In this study, Finite Difference Method was used to find out the coefficients of optimal heating profiles. Through investigation, the optimal results using Finite Difference Method show that temperature difference between surface and center of sheet can be remarkably minimized with satisfying temperature of forming window.

  1. Individual difference predictors of change in career adaptability over time

    NARCIS (Netherlands)

    Zacher, Hannes

    2014-01-01

    Career adaptability is a psychosocial construct that reflects individuals' resources for managing career tasks and challenges. This study investigated the effects of demographic characteristics and three sets of individual difference variables (Big Five personality traits, core self-evaluations, and

  2. Individual difference predictors of change in career adaptability over time

    NARCIS (Netherlands)

    Zacher, Hannes

    2014-01-01

    Career adaptability is a psychosocial construct that reflects individuals' resources for managing career tasks and challenges. This study investigated the effects of demographic characteristics and three sets of individual difference variables (Big Five personality traits, core self-evaluations, and

  3. Reflections on the different sides of idleness in contemporary times

    OpenAIRE

    Patrícia Zaczuk Bassinello; Valdemir Miotello

    2015-01-01

    Over the last century, idleness experienced a modernization and democratization process especially with the crisis of a society focused on work – the post-Industrial Revolution - and the emergence of new ideas that put the free time, the leisure and recreation in the role of structural elements of the new social context and like tools for the new ways of life. In this work, we we seek to focus on the significant aspects of reality and function of leisure in our time, clarifying their relation...

  4. The effect of different cochlear implant microphones on acoustic hearing individuals’ binaural benefits for speech perception in noise

    Science.gov (United States)

    Aronoff, Justin M.; Freed, Daniel J.; Fisher, Laurel M.; Pal, Ivan; Soli, Sigfrid D.

    2011-01-01

    Objectives Cochlear implant microphones differ in placement, frequency response, and other characteristics such as whether they are directional. Although normal hearing individuals are often used as controls in studies examining cochlear implant users’ binaural benefits, the considerable differences across cochlear implant microphones make such comparisons potentially misleading. The goal of this study was to examine binaural benefits for speech perception in noise for normal hearing individuals using stimuli processed by head-related transfer functions (HRTFs) based on the different cochlear implant microphones. Design HRTFs were created for different cochlear implant microphones and used to test participants on the Hearing in Noise Test. Experiment 1 tested cochlear implant users and normal hearing individuals with HRTF-processed stimuli and with sound field testing to determine whether the HRTFs adequately simulated sound field testing. Experiment 2 determined the measurement error and performance-intensity function for the Hearing in Noise Test with normal hearing individuals listening to stimuli processed with the various HRTFs. Experiment 3 compared normal hearing listeners’ performance across HRTFs to determine how the HRTFs affected performance. Experiment 4 evaluated binaural benefits for normal hearing listeners using the various HRTFs, including ones that were modified to investigate the contributions of interaural time and level cues. Results The results indicated that the HRTFs adequately simulated sound field testing for the Hearing in Noise Test. They also demonstrated that the test-retest reliability and performance-intensity function were consistent across HRTFs, and that the measurement error for the test was 1.3 dB, with a change in signal-to-noise ratio of 1 dB reflecting a 10% change in intelligibility. There were significant differences in performance when using the various HRTFs, with particularly good thresholds for the HRTF based on the

  5. The effect of different cochlear implant microphones on acoustic hearing individuals' binaural benefits for speech perception in noise.

    Science.gov (United States)

    Aronoff, Justin M; Freed, Daniel J; Fisher, Laurel M; Pal, Ivan; Soli, Sigfrid D

    2011-01-01

    Cochlear implant microphones differ in placement, frequency response, and other characteristics such as whether they are directional. Although normal-hearing (NH) individuals are often used as controls in studies examining cochlear implant users' binaural benefits, the considerable differences across cochlear implant microphones make such comparisons potentially misleading. The goal of this study was to examine binaural benefits for speech perception in noise for NH individuals using stimuli processed by head-related transfer functions (HRTFs) based on the different cochlear implant microphones. HRTFs were created for different cochlear implant microphones and used to test participants on the Hearing in Noise Test. Experiment 1 tested cochlear implant users and NH individuals with HRTF-processed stimuli and with sound field (SF) testing to determine whether the HRTFs adequately simulated SF testing. Experiment 2 determined the measurement error and performance-intensity function for the Hearing in Noise Test with NH individuals listening to stimuli processed with the various HRTFs. Experiment 3 compared NH listeners' performance across HRTFs to determine how the HRTFs affected performance. Experiment 4 evaluated binaural benefits for NH listeners using the various HRTFs, including ones that were modified to investigate the contributions of interaural time and level cues. The results indicated that the HRTFs adequately simulated SF testing for the Hearing in Noise Test. They also demonstrated that the test-retest reliability and performance-intensity function were consistent across HRTFs, and that the measurement error for the test was 1.3 dB, with a change in signal-to-noise ratio of 1 dB reflecting a 10% change in intelligibility. There were significant differences in performance when using the various HRTFs, with particularly good thresholds for the HRTF based on the directional microphone when the speech and masker were spatially separated, emphasizing the

  6. University Instructors' Ratings Profiles: Stability Over Time, and Disciplinary Differences.

    Science.gov (United States)

    Hativa, Nira; Raviv, Alona

    1996-01-01

    A study compared the teaching behaviors of University of Tel Aviv (Israel) physics and chemistry faculty over two consecutive years, at mid- and end-semester. Findings indicate a high degree of stability in behaviors over time, with no clear-cut improvement during a semester except for faculty undertaking special instructional improvement…

  7. Differences in auditory timing between human and nonhuman primates

    NARCIS (Netherlands)

    Honing, H.; Merchant, H.

    2014-01-01

    The gradual audiomotor evolution hypothesis is proposed as an alternative interpretation to the auditory timing mechanisms discussed in Ackermann et al.'s article. This hypothesis accommodates the fact that the performance of nonhuman primates is comparable to humans in single-interval tasks (such

  8. Reflections on the different sides of idleness in contemporary times

    National Research Council Canada - National Science Library

    Patrícia Zaczuk Bassinello; Valdemir Miotello

    2015-01-01

    ... – the post-Industrial Revolution - and the emergence of new ideas that put the free time, the leisure and recreation in the role of structural elements of the new social context and like tools for the new ways of life...

  9. Time dependent wave envelope finite difference analysis of sound propagation

    Science.gov (United States)

    Baumeister, K. J.

    1984-01-01

    A transient finite difference wave envelope formulation is presented for sound propagation, without steady flow. Before the finite difference equations are formulated, the governing wave equation is first transformed to a form whose solution tends not to oscillate along the propagation direction. This transformation reduces the required number of grid points by an order of magnitude. Physically, the transformed pressure represents the amplitude of the conventional sound wave. The derivation for the wave envelope transient wave equation and appropriate boundary conditions are presented as well as the difference equations and stability requirements. To illustrate the method, example solutions are presented for sound propagation in a straight hard wall duct and in a two dimensional straight soft wall duct. The numerical results are in good agreement with exact analytical results.

  10. [Family formation in Flanders: new patterns, different timing].

    Science.gov (United States)

    Lee, H Y; Rajulton, F; Wijewickrema, S; Lesthaeghe, R

    1987-01-01

    "The article presents a statistical study of the starting age and the speed of transitions in the process of family formation in Flanders. It contrasts two sets of generations, three groups according to educational achievement and three groups with differing religious practice. The methodology of shifted proportional hazard models is used and transition probabilities are fed into a semi-Markovian chain. Higher educational achievement results in later starting points, but not in a differing pace once started. By contrast, lower religious involvement speeds up the transitions to first sexual contact and premarital cohabitation, while it considerably retards the transition to parenthood among the generations born after 1950." (SUMMARY IN ENG AND FRE)

  11. Timing Analysis with INTEGRAL: Comparing Different Reconstruction Algorithms

    Science.gov (United States)

    Grinberg, V.; Kreykenboehm, I.; Fuerst, F.; Wilms, J.; Pottschmidt, K.; Bel, M. Cadolle; Rodriquez, J.; Marcu, D. M.; Suchy, S.; Markowitz, A.; hide

    2010-01-01

    INTEGRAL is one of the few instruments capable of detecting X-rays above 20keV. It is therefore in principle well suited for studying X-ray variability in this regime. Because INTEGRAL uses coded mask instruments for imaging, the reconstruction of light curves of X-ray sources is highly non-trivial. We present results from the comparison of two commonly employed algorithms, which primarily measure flux from mask deconvolution (ii-lc-extract) and from calculating the pixel illuminated fraction (ii-light). Both methods agree well for timescales above about 10 s, the highest time resolution for which image reconstruction is possible. For higher time resolution, ii-light produces meaningful results, although the overall variance of the lightcurves is not preserved.

  12. Breast reconstruction: Correlation between different procedures, reconstruction timing and complications

    Directory of Open Access Journals (Sweden)

    Anđelkov Katarina

    2011-01-01

    Full Text Available Introduction. Improved psychophysical condition after breast reconstruction in women has been well documented Objective. To determine the most optimal technique with minimal morbidity, the authors examined their results and complications based on reconstruction timing (immediate and delayed reconstruction and three reconstruction methods: TRAM flap, latissimus dorsi flap and reconstruction with tissue expanders and implants. Methods. Reconstruction was performed in 60 women of mean age 51.1 years. We analyzed risk factors: age, body mass index (BMI, smoking history and radiation therapy in correlation with timing and method of reconstruction. Complications of all three methods of reconstruction were under 1.5-2-year follow-up after the reconstruction. All data were statistically analyzed. Results. Only radiation had significant influence on the occurrence of complications both before and after the reconstruction, while age, smoking and BMI had no considerable influence of the development of complications. There were no statistically significant correlation between the incidence of complications, time and method of reconstruction. Conclusion. Any of the aforementioned breast reconstruction techniques can yield good results and a low rate of re-operations. To choose the best method, the patient needs to be as well informed as possible about the options including the risks and benefits of each method.

  13. Esophageal impedance baseline according to different time intervals

    Directory of Open Access Journals (Sweden)

    Ummarino Dario

    2012-06-01

    Full Text Available Abstract Background The impedance baseline has been shown to reflect esophageal integrity, and to be decreased in patients with esophagitis. However, different methods for the determination of the impedance baseline have not been compared. Methods The median impedance baseline was calculated in 10 consecutive multichannel intraluminal impedance recordings in children with non-erosive reflux disease. All children underwent an endoscopy with a biopsy as part of the clinical work-up to exclude esophagitis. The impedance baseline was obtained both by including and excluding all impedance episodes (IE; reflux, swallows and gas episodes during the full recording, and during the first 1-minute period without an IE every hour (method 1, every 2 hours (method 2 or every 4 hours (method 3. The impedance baseline obtained during the full recording was set at 100%, and the variation (difference in impedance baseline for the different methods and variability (difference in impedance baseline during one analysis period were assessed. Results None of the participants had esophagitis. The mean difference over the six channels between the impedance baseline over the total recording with and without IE was approximately 2.5%, and comparable for each channel (range 0.47% to 5.55%. A mean of 1,028 IEs were excluded in each tracing, and it took between 4 and 24 hours to delete all events in one tracing. The difference in the impedance baseline obtained with and without IEs was mainly caused by the gas episodes in the upper channels and swallows in the lower channels. The median impedance baseline according to the three one-minute analysis methods was comparable to the median impedance baseline according to the 24 hour analysis. Conclusions The automatic determination of the median impedance baseline over the total tracing including IEs is an adequate method. In isolated tracings with numerous IEs, the calculation of the median impedance baseline over one minute

  14. It is time to consider cultural differences in debriefing

    DEFF Research Database (Denmark)

    Chung, Hyun Soo; Dieckmann, Peter; Issenberg, Saul Barry

    2013-01-01

    Debriefing plays a critical role in facilitated reflection of simulation after the experiential component of simulation-based learning. The concept of framing and reflective learning in a debriefing session has emanated primarily from Western cultures. However, non-Western cultures have significa...... debriefing sessions. Our goal was to raise awareness of cultural differences and stimulate work to make progress in this regard.......Debriefing plays a critical role in facilitated reflection of simulation after the experiential component of simulation-based learning. The concept of framing and reflective learning in a debriefing session has emanated primarily from Western cultures. However, non-Western cultures have significant...... characteristics that manifest themselves in teaching and learning practices substantially different from Western cultures. We need to consider how to balance standardization in debriefing with a culture-sensitive interpretation of simulation-based learning so that learners receive the maximum benefit from...

  15. Semidiscrete central difference method in time for determining surface temperatures

    Directory of Open Access Journals (Sweden)

    Zhi Qian

    2005-01-01

    the data. Eldén (1995 has used a difference method for solving this problem, but he did not obtain the convergence at x=0. In this paper, we gave a logarithmic stability of the approximation solution at x=0 under a stronger a priori assumption ‖u(0,t‖p≤E with p>1/2. A numerical example shows that the computational effect of this method is satisfactory.

  16. Different RAN Components Relate to Reading at Different Points in Time

    Science.gov (United States)

    Georgiou, George K.; Papadopoulos, Timothy C.; Kaizer, Eleni L.

    2014-01-01

    The present 10-year longitudinal study examined how rapid automatized naming (RAN) components--articulation time and pause time--relate to reading fluency. Seventy-five Greek-speaking children were followed from Grade 1 to Grade 10 and were assessed five times (in Grades 1, 2, 4, 6, and 10) on RAN (digits and objects) and reading fluency (word…

  17. Time and space: The difference between following time headway and distance headway instructions

    NARCIS (Netherlands)

    Risto, M.; Martens, M.H.

    2013-01-01

    In order to guarantee safety, drivers are advised to keep large enough headways. However, headway advice is often provided in terms of time headway, without knowing whether this is the right way of presenting the advice. According to a psychophysics theory, attaining a time headway would indeed

  18. Time and Space: The difference between following time headway and distance headway instructions

    NARCIS (Netherlands)

    Risto, Malte; Martens, Marieke Hendrikje

    2013-01-01

    In order to guarantee safety, drivers are advised to keep large enough headways. However, headway advice is often provided in terms of time headway, without knowing whether this is the right way of presenting the advice. According to a psychophysics theory, attaining a time headway would indeed

  19. Time and space: The difference between following time headway and distance headway instructions

    NARCIS (Netherlands)

    Risto, M.; Martens, M.H.

    2013-01-01

    In order to guarantee safety, drivers are advised to keep large enough headways. However, headway advice is often provided in terms of time headway, without knowing whether this is the right way of presenting the advice. According to a psychophysics theory, attaining a time headway would indeed allo

  20. Time and Space: The difference between following time headway and distance headway instructions

    NARCIS (Netherlands)

    Risto, M.; Martens, M.H.

    2013-01-01

    In order to guarantee safety, drivers are advised to keep large enough headways. However, headway advice is often provided in terms of time headway, without knowing whether this is the right way of presenting the advice. According to a psychophysics theory, attaining a time headway would indeed allo

  1. Market size structure and small business lending : Are crisis times different from normal times?

    NARCIS (Netherlands)

    Berger, Allen N.; Cerqueiro, G.M.; Penas, Maria

    2015-01-01

    Conventional wisdom holds that small banks have comparative advantages vis-à-vis large banks in serving small firms, while recent literature suggests this may not be the case. Using a panel of recent US start-ups, we investigate how small bank presence affects these firms in normal times (2004–06) a

  2. Different Gestalt Processing for Different Actions? Comparing Object-Directed Reaching and Looking Time Measures

    Science.gov (United States)

    Vishton, P.M.; Ware, E.A.; Badger, A.N.

    2005-01-01

    Six experiments compared the Gestalt processing that mediates infant reaching and looking behaviors. Experiment 1 demonstrated that the positioning and timing of 8- and 9-month-olds' reaching was influenced by remembered relative motion. Experiment 2 suggested that a visible gap, without this relative motion, was not sufficient to produce these…

  3. Different Gestalt Processing for Different Actions? Comparing Object-Directed Reaching and Looking Time Measures

    Science.gov (United States)

    Vishton, P.M.; Ware, E.A.; Badger, A.N.

    2005-01-01

    Six experiments compared the Gestalt processing that mediates infant reaching and looking behaviors. Experiment 1 demonstrated that the positioning and timing of 8- and 9-month-olds' reaching was influenced by remembered relative motion. Experiment 2 suggested that a visible gap, without this relative motion, was not sufficient to produce these…

  4. Sebaceous carcinoma of the eyelid - different diagnostic times, different outcomes: case reports

    Directory of Open Access Journals (Sweden)

    Lucas Monferrari Monteiro Vianna

    2011-12-01

    Full Text Available Sebaceous carcinoma of the eyelid is a very rare slow-growing tumor and is considered an aggressive eyelid neoplasm. It can reach mortality rate of about 6%. Diagnosis is often delayed because of its ability to masquerade as other periocular lesions, both clinically and histologically. We present three cases of sebaceous carcinoma, with different surgical outcomes, showing the importance of early diagnosis.

  5. Investment gestation lags: The difference between time-to-build and delivery lags

    OpenAIRE

    PEETERS, Marga

    1996-01-01

    The timing of investment and capital stock accumulation can differ as a result of time-to-build or delivery lags. In this study calibration methods are used to illustrate the difference in these sources of gestation lags.

  6. Limited segregation of different types of sound localization information among classes of units in the inferior colliculus.

    Science.gov (United States)

    Chase, Steven M; Young, Eric D

    2005-08-17

    The auditory system uses three cues to decode sound location: interaural time differences (ITDs), interaural level differences (ILDs), and spectral notches (SNs). Initial processing of these cues is done in separate brainstem nuclei, with ITDs in the medial superior olive, ILDs in the lateral superior olive, and SNs in the dorsal cochlear nucleus. This work addresses the nature of the convergence of localization information in the central nucleus of the inferior colliculus (ICC). Ramachandran et al. (1999) argued that ICC neurons of types V, I, and O, respectively, receive their predominant inputs from ITD-, ILD-, and SN-sensitive brainstem nuclei, suggesting that these ICC response types should be differentially sensitive to localization cues. Here, single-unit responses to simultaneous manipulation of pairs of localization cues were recorded, and the mutual information between discharge rate and individual cues was quantified. Although rate responses to cue variation were generally consistent with those expected from the hypothesized anatomical connections, the differences in information were not as large as expected. Type I units provide the most information, especially about SNs in the physiologically useful range. Type I and O units provide information about ILDs, even at low frequencies at which actual ILDs are very small. ITD information is provided by a subset of all low-frequency neurons. Type V neurons provide information mainly about ITDs and the average binaural intensity. These results are the first to quantify the relative representation of cues in terms of information and suggest a variety of degrees of cue integration in the ICC.

  7. Does time differ from change? Philosophical appraisal of the problem of time in quantum gravity and in physics

    Science.gov (United States)

    de Saint-Ours, Alexis

    2015-11-01

    After reviewing the problem of time in Quantum Gravity, I compare from a philosophical perspective, both Carlo Rovelli's and Julian Barbour's (before Shape Dynamics) understanding of time in Quantum Gravity and in dynamics in general, trying to show that those two relational understandings of time differ. Rovelli argues that there is change without time and that time can be abstracted from any change whereas Barbour claims that some motions are better than others for constituting duration standards and that time is to be abstracted from all change in the universe. I conclude by a few remarks on Bergson's criticism of physics in the light of those debates trying to show that both Rovelli and Barbour give surrationalist (as Bachelard understood it) answers to the critique of spatialized time in Physics.

  8. Different target-discrimination times can be followed by the same saccade-initiation timing in different stimulus conditions during visual searches.

    Science.gov (United States)

    Tanaka, Tomohiro; Nishida, Satoshi; Ogawa, Tadashi

    2015-07-01

    The neuronal processes that underlie visual searches can be divided into two stages: target discrimination and saccade preparation/generation. This predicts that the length of time of the prediscrimination stage varies according to the search difficulty across different stimulus conditions, whereas the length of the latter postdiscrimination stage is stimulus invariant. However, recent studies have suggested that the length of the postdiscrimination interval changes with different stimulus conditions. To address whether and how the visual stimulus affects determination of the postdiscrimination interval, we recorded single-neuron activity in the lateral intraparietal area (LIP) when monkeys (Macaca fuscata) performed a color-singleton search involving four stimulus conditions that differed regarding luminance (Bright vs. Dim) and target-distractor color similarity (Easy vs. Difficult). We specifically focused on comparing activities between the Bright-Difficult and Dim-Easy conditions, in which the visual stimuli were considerably different, but the mean reaction times were indistinguishable. This allowed us to examine the neuronal activity when the difference in the degree of search speed between different stimulus conditions was minimal. We found that not only prediscrimination but also postdiscrimination intervals varied across stimulus conditions: the postdiscrimination interval was longer in the Dim-Easy condition than in the Bright-Difficult condition. Further analysis revealed that the postdiscrimination interval might vary with stimulus luminance. A computer simulation using an accumulation-to-threshold model suggested that the luminance-related difference in visual response strength at discrimination time could be the cause of different postdiscrimination intervals.

  9. Directional spectrum of ocean waves from array measurements using phase/time/path difference methods

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, A.A.; Sarma, Y.V.B.; Menon, H.B.

    Wave direction has for the first time been consistently, accurately and unambiguously evaluated from array measurements using the phase/time/path difference (PTPD) methods of Esteva in case of polygonal arrays and Borgman in case of linear arrays...

  10. A newly discovered superoantero-orbital sinus connecting to the interaural canal may play a role in zebra finch hearing

    DEFF Research Database (Denmark)

    Jensen, Kenneth Kragh; Christensen-Dalsgaard, Jakob; Suthers, Roderick A.

    on the amplitude gain and time delay through IAC. Theoretically, different combinations of frequency dependent gains and delays produce very different directionalities of the ears but it is still uncertain how gain and delay can be shaped by evolution. We have discovered that a large forehead sinus superoanterior...... to the orbits (superoantero-orbital sinus, SAOS) connects to the IAC via a tube inferomedial to the orbits (IMT). SAOS has a very complex shape with connections through an arc over the eye to the bullae of each ear and also to two smaller lateral sinuses in front of each eye. The contribution of this structure...

  11. Effects of Different Time-Dependent Couplings on Two-Atom Entanglement

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ling; GAO Wen-Bin; YANG Guo-Hui; SONG He-Shan

    2007-01-01

    The effects of different time-independent and time-dependent couplings on two-atom entanglement are studied. The results show that the effects depend on the initial state. For the initial state |ee0>, it is found that different time-independent couplings make the case without entanglement exhibit entanglement, and time-dependent couplings turn the irregular entanglement regions into regular one. Under the case of decay, for the initial state |eg0>, the different time-dependent couplings have disbenefit.

  12. The Newsvendor Problem with Different Delivery Time, Resalable Returns, and an Additional Order

    National Research Council Canada - National Science Library

    Zeng, Fue; Chi, Yunjia; Zheng, Jinhui

    2015-01-01

    .... Considering demands for different delivery time, we explore a newsvendor model with resalable returns and an additional order to optimize the procurement decision under a stochastic demand distribution...

  13. A study on the frequency of participation and time spent on sport in different organisational settings

    NARCIS (Netherlands)

    Borgers, J.; Breedveld, K.; Tiessen-Raaphorst, A.; Thibaut, E.; Vandermeerschen, H.; Vos, S.B.; Scheerder, J.

    2016-01-01

    Research question: As a result of the expansion of opportunities for leisure-time sport participation (LTSP), the question arises if differing organisational settings relate to differences in participation behaviour. This paper compares participation frequency and time spent on sport between club-or

  14. A Maximum Time Difference Pipelined Arithmetic Unit Based on CMOS Gate Array

    Institute of Scientific and Technical Information of China (English)

    唐志敏; 夏培肃

    1995-01-01

    This paper describes a maximum time difference pipelined arithmetic chip,the 36-bit adder and subtractor based on 1.5μm CMOS gate array.The chip can operate at 60MHz,and consumes less than 0.5Watt.The results are also studied,and a more precise model of delay time difference is proposed.

  15. Gender Differences in Time Use among Adolescents in Developing Countries: Implications of Rising School Enrollment Rates

    Science.gov (United States)

    Lloyd, Cynthia B.; Grant, Monica; Ritchie, Amanda

    2008-01-01

    This comparative analysis of gender differences in time use among adolescents uses surveys from five developing countries and is motivated by an interest in gender role socialization and gendered patterns of behavior during adolescence. Exploring differences in work (both noneconomic household work and labor market work) and leisure time among…

  16. Ignoring Individual Differences in Times of Assessment in Growth Curve Modeling

    Science.gov (United States)

    Coulombe, Patrick; Selig, James P.; Delaney, Harold D.

    2016-01-01

    Researchers often collect longitudinal data to model change over time in a phenomenon of interest. Inevitably, there will be some variation across individuals in specific time intervals between assessments. In this simulation study of growth curve modeling, we investigate how ignoring individual differences in time points when modeling change over…

  17. A wavelet based approach to measure and manage contagion at different time scales

    Science.gov (United States)

    Berger, Theo

    2015-10-01

    We decompose financial return series of US stocks into different time scales with respect to different market regimes. First, we examine dependence structure of decomposed financial return series and analyze the impact of the current financial crisis on contagion and changing interdependencies as well as upper and lower tail dependence for different time scales. Second, we demonstrate to which extent the information of different time scales can be used in the context of portfolio management. As a result, minimizing the variance of short-run noise outperforms a portfolio that minimizes the variance of the return series.

  18. Synchronization of Different Fractional Order Time-Delay Chaotic Systems Using Active Control

    Directory of Open Access Journals (Sweden)

    Jianeng Tang

    2014-01-01

    Full Text Available Chaos synchronization of different fractional order time-delay chaotic systems is considered. Based on the Laplace transform theory, the conditions for achieving synchronization of different fractional order time-delay chaotic systems are analyzed by use of active control technique. Then numerical simulations are provided to verify the effectiveness and feasibility of the developed method. At last, effects of the fraction order and the time delay on synchronization are further researched.

  19. Synchronization of Different Fractional Order Time-Delay Chaotic Systems Using Active Control

    OpenAIRE

    Jianeng Tang

    2014-01-01

    Chaos synchronization of different fractional order time-delay chaotic systems is considered. Based on the Laplace transform theory, the conditions for achieving synchronization of different fractional order time-delay chaotic systems are analyzed by use of active control technique. Then numerical simulations are provided to verify the effectiveness and feasibility of the developed method. At last, effects of the fraction order and the time delay on synchronization are further researched.

  20. Time-Domain Nuclear Magnetic Resonance Investigation of Water Dynamics in Different Ginger Cultivars.

    Science.gov (United States)

    Huang, Chongyang; Zhou, Qi; Gao, Shan; Bao, Qingjia; Chen, Fang; Liu, Chaoyang

    2016-01-20

    Different ginger cultivars may contain different nutritional and medicinal values. In this study, a time-domain nuclear magnetic resonance method was employed to study water dynamics in different ginger cultivars. Significant differences in transverse relaxation time T2 values assigned to the distribution of water in different parts of the plant were observed between Henan ginger and four other ginger cultivars. Ion concentration and metabolic analysis showed similar differences in Mn ion concentrations and organic solutes among the different ginger cultivars, respectively. On the basis of Pearson's correlation analysis, many organic solutes and 6-gingerol, the main active substance of ginger, exhibited significant correlations with water distribution as determined by NMR T2 relaxation, suggesting that the organic solute differences may impact water distribution. Our work demonstrates that low-field NMR relaxometry provides useful information about water dynamics in different ginger cultivars as affected by the presence of different organic solutes.

  1. Effect of gait speed on gait rhythmicity in Parkinson's disease: variability of stride time and swing time respond differently

    Directory of Open Access Journals (Sweden)

    Peretz Chava

    2005-07-01

    Full Text Available Abstract Background The ability to maintain a steady gait rhythm is impaired in patients with Parkinson's disease (PD. This aspect of locomotor dyscontrol, which likely reflects impaired automaticity in PD, can be quantified by measuring the stride-to-stride variability of gait timing. Previous work has shown an increase in both the variability of the stride time and swing time in PD, but the origins of these changes are not fully understood. Patients with PD also generally walk with a reduced gait speed, a potential confounder of the observed changes in variability. The purpose of the present study was to examine the relationship between walking speed and gait variability. Methods Stride time variability and swing time variability were measured in 36 patients with PD (Hoehn and Yahr stage 2–2.5 and 30 healthy controls who walked on a treadmill at four different speeds: 1 Comfortable walking speed (CWS, 2 80% of CWS 3 90% of CWS, and 4 110% of CWS. In addition, we studied the effects of walking slowly on level ground, both with and without a walker. Results Consistent with previous findings, increased variability of stride time and swing time was observed in the patients with PD in CWS, compared to controls. In both groups, there was a small but significant association between treadmill gait speed and stride time variability such that higher speeds were associated with lower (better values of stride time variability (p = 0.0002. In contrast, swing time variability did not change in response to changes in gait speed. Similar results were observed with walking on level ground. Conclusion The present results demonstrate that swing time variability is independent of gait speed, at least over the range studied, and therefore, that it may be used as a speed-independent marker of rhythmicity and gait steadiness. Since walking speed did not affect stride time variability and swing time variability in the same way, it appears that these two aspects of

  2. Annoyance due to railway vibration at different times of the day.

    Science.gov (United States)

    Peris, Eulalia; Woodcock, James; Sica, Gennaro; Moorhouse, Andrew T; Waddington, David C

    2012-02-01

    The time of day when vibration occurs is considered as a factor influencing the human response to vibration. The aim of the present paper is to identify the times of day during which railway vibration causes the greatest annoyance, to measure the differences between annoyance responses for different time periods and to obtain estimates of the time of day penalties. This was achieved using data from case studies comprised of face-to-face interviews and internal vibration measurements (N=755). Results indicate that vibration annoyance differs with time of day and that separate time of day weights can be applied when considering exposure-response relationships from railway vibration in residential environments. © 2012 Acoustical Society of America

  3. Three-dimensional viscoelastic time-domain finite-difference seismic modelling using the staggered Adams-Bashforth time integrator

    Science.gov (United States)

    Bohlen, Thomas; Wittkamp, Florian

    2016-03-01

    We analyse the performance of a higher order accurate staggered viscoelastic time-domain finite-difference method, in which the staggered Adams-Bashforth (ABS) third-order and fourth-order accurate time integrators are used for temporal discretization. ABS is a multistep method that uses previously calculated wavefields to increase the order of accuracy in time. The analysis shows that the numerical dispersion is much lower than that of the widely used second-order leapfrog method. Numerical dissipation is introduced by the ABS method which is significantly smaller for fourth-order than third-order accuracy. In 1-D and 3-D simulation experiments, we verify the convincing improvements of simulation accuracy of the fourth-order ABS method. In a realistic elastic 3-D scenario, the computing time reduces by a factor of approximately 2.4, whereas the memory requirements increase by approximately a factor of 2.2. The ABS method thus provides an alternative strategy to increase the simulation accuracy in time by investing computer memory instead of computing time.

  4. Different Ultimate Factors Define Timing of Breeding in Two Related Species.

    Science.gov (United States)

    Pakanen, Veli-Matti; Orell, Markku; Vatka, Emma; Rytkönen, Seppo; Broggi, Juli

    2016-01-01

    Correct reproductive timing is crucial for fitness. Breeding phenology even in similar species can differ due to different selective pressures on the timing of reproduction. These selection pressures define species' responses to warming springs. The temporal match-mismatch hypothesis suggests that timing of breeding in animals is selected to match with food availability (synchrony). Alternatively, time-dependent breeding success (the date hypothesis) can result from other seasonally deteriorating ecological conditions such as intra- or interspecific competition or predation. We studied the effects of two ultimate factors on the timing of breeding, synchrony and other time-dependent factors (time-dependence), in sympatric populations of two related forest-dwelling passerine species, the great tit (Parus major) and the willow tit (Poecile montanus) by modelling recruitment with long-term capture-recapture data. We hypothesized that these two factors have different relevance for fitness in these species. We found that local recruitment in both species showed quadratic relationships with both time-dependence and synchrony. However, the importance of these factors was markedly different between the studied species. Caterpillar food played a predominant role in predicting the timing of breeding of the great tit. In contrast, for the willow tit time-dependence modelled as timing in relation to conspecifics was more important for local recruitment than synchrony. High caterpillar biomass experienced during the pre- and post-fledging periods increased local recruitment of both species. These contrasting results confirm that these species experience different selective pressures upon the timing of breeding, and hence responses to climate change may differ. Detailed information about life-history strategies is required to understand the effects of climate change, even in closely related taxa. The temporal match-mismatch hypothesis should be extended to consider subsequent

  5. Between-mode-differences in the value of travel time: Self-selection or strategic behaviour?

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Hjorth, Katrine; Lyk-Jensen, Stéphanie Vincent

    2010-01-01

    Using stated preference survey data, we measure the value of travel time for several transport modes. We find, like many before us, that the value of travel time varies across modes in the opposite direction of what would be the consequence of differences in comfort. We examine three candidate...... causes for the observed differences: Comfort effects, self-selection and strategic behaviour of respondents. Using experiments with both the current and an alternative mode we find that the differences in the value of travel time are consistent with self-selection and comfort effects. Moreover...

  6. Fractional Differential Equations in Terms of Comparison Results and Lyapunov Stability with Initial Time Difference

    Directory of Open Access Journals (Sweden)

    Coşkun Yakar

    2010-01-01

    Full Text Available The qualitative behavior of a perturbed fractional-order differential equation with Caputo's derivative that differs in initial position and initial time with respect to the unperturbed fractional-order differential equation with Caputo's derivative has been investigated. We compare the classical notion of stability to the notion of initial time difference stability for fractional-order differential equations in Caputo's sense. We present a comparison result which again gives the null solution a central role in the comparison fractional-order differential equation when establishing initial time difference stability of the perturbed fractional-order differential equation with respect to the unperturbed fractional-order differential equation.

  7. Changes in occupational class differences in leisure-time physical activity: a follow-up study

    Directory of Open Access Journals (Sweden)

    Lahelma Eero

    2011-03-01

    Full Text Available Abstract Background Physical activity is known to have health benefits across population groups. However, less is known about changes over time in socioeconomic differences in leisure-time physical activity and the reasons for the changes. We hypothesised that class differences in leisure-time physical activity would widen over time due to declining physical activity among the lower occupational classes. We examined whether occupational class differences in leisure-time physical activity change over time in a cohort of Finnish middle-aged women and men. We also examined whether a set of selected covariates could account for the observed changes. Methods The data were derived from the Helsinki Health Study cohort mail surveys; the respondents were 40-60-year-old employees of the City of Helsinki at baseline in 2000-2002 (n = 8960, response rate 67%. Follow-up questionnaires were sent to the baseline respondents in 2007 (n = 7332, response rate 83%. The outcome measure was leisure-time physical activity, including commuting, converted to metabolic equivalent tasks (MET. Socioeconomic position was measured by occupational class (professionals, semi-professionals, routine non-manual employees and manual workers. The covariates included baseline age, marital status, limiting long-lasting illness, common mental disorders, job strain, physical and mental health functioning, smoking, body mass index, and employment status at follow-up. Firstly the analyses focused on changes over time in age adjusted prevalence of leisure-time physical activity. Secondly, logistic regression analysis was used to adjust for covariates of changes in occupational class differences in leisure-time physical activity. Results At baseline there were no occupational class differences in leisure-time physical activity. Over the follow-up leisure-time physical activity increased among those in the higher classes and decreased among manual workers, suggesting the emergence of

  8. Isometric fatigue patterns in time and time-frequency domains of triceps surae muscle in different knee positions.

    Science.gov (United States)

    Pereira, Glauber Ribeiro; de Oliveira, Liliam Fernandes; Nadal, Jurandir

    2011-08-01

    The occurrence of fatigue in triceps surae (TS) muscles during sustained plantar flexion contraction is investigated by means of the RMS electromyogram (EMG) and the instantaneous median frequency (IMF) of the short time Fourier transform (STFT). Six male subjects realized a 40% maximal plantar flexion isometric voluntary contraction until fatigue in two knee positions. Electrodes were positioned on gastrocnemius medialis, gastrocnemius lateralis and soleus muscles. The torque (TO) and EMG signals were synchronized. The RMS and the median of the IMF values were obtained, respectively, for each 250 ms and 1s windows of signal. Each signal was segmented into 10 epochs, from which the mean values of IMF, RMS and TO were obtained and submitted to linear regressions to determine parameter trends. Friedman test with the Dunn's post hoc were used to test for differences among muscles activation for each knee position and among slopes of regression curves, as well as to observe changes in TS RMS values over time. The results indicate different activation strategies with the knee extended (KE) in contrast to knee flexed (KF). With the KE, the gastrocnemii showed typical fatigue behavior with significant (p<0.05) IMF reductions and RMS increases over time, while soleus showed concomitant RMS and IMF increases (p<0.05) suggesting an increased soleus contribution to the torque production. With KF, the gastrocnemii were under activated, increasing the role of soleus. Thus, time-frequency analysis represented an important tool for TS muscular fatigue evaluation, allowing differentiates the role of soleus muscle.

  9. LONG-TIME BEHAVIOR OF FINITE DIFFERENCE SOLUTIONS OF A NONLINEAR SCHRODINGER EQUATION WITH WEAKLY DAMPED

    Institute of Scientific and Technical Information of China (English)

    Fa-yong Zhang; Shu-juan Lu

    2001-01-01

    A weakly demped Schrodinger equation possessing a global attractor are considered.The dynamical properties of a class of finite difference scheme are analysed. The exsitence of global attractor is proved for the discrete system. The stability of the difference scheme and the error estimate of the difference solution are obtained in the autonomous system case. Finally, long-time stability and convergence of the class of finite difference scheme also are analysed in the nonautonomous system case.

  10. STUDY ON MIXIS POTENTIAL OF ROTIFER RESTING EGGS( BRACHIONUS PLICATILIS ) WITH DIFFERENT COLLECTION TIMES AND DIFFERENT PRESERVATION PERIODS

    Institute of Scientific and Technical Information of China (English)

    周利; 郑严; 相建海

    2001-01-01

    The present study investigated the possible changes in the mixis potential of rotifer resting eggs produced by a single stock of Brachionus plicatilis and collected and preserved annually from 1985 - 1998. Several clones derived from each batch of resting eggs were cultured under the same conditions for 21 days. The percentage of clones appearing resting eggs and the average yield of resting eggs produced from each clone were recorded and statistically analyzed to find the differences between the mixis potential of those resting egg batches. Results showed that different batches of resting eggs had different mictic levels among their descendent clones; but no regular relationship was found between the mixis potential of resting eggs and their collection times/preservation periods. Several internal and external factors that might affect the mixis potential of resting eggs were discussed.

  11. STUDY ON MIXIS POTENTIAL OF ROTIFER RESTING EGGS (BRACHIONUS PLICATILIS) WITH DIFFERENT COLLECTION TIMES AND DIFFERENT PRESERVATION PERIODS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The present study investigated the possible changes in the mixis potential of rotifer resting eggs produced by a single stock of Brachionus plicatilis and collected and preserved annually from 1985-1998. Several clones derived from each batch of resting eggs were cultured under the same conditions for 21 days. The percentage of clones appearing resting eggs and the average yield of resting eggs produced from each clone were recorded and statistically analyzed to find the differences between the mixis potential of those resting egg batches. Results showed that different batches of resting eggs had different mictic levels among their descendent clones; but no regular relationship was found between the mixis potential of resting eggs and their collection times/preservation periods. Several internal and external factors that might affect the mixis potential of resting eggs were discussed.

  12. Empirical study on structural properties in temporal networks under different time scales

    Science.gov (United States)

    Chen, Duanbing

    2015-12-01

    Many network analyzing methods are usually based on static networks. However, temporal networks should be considered so as to investigate real complex systems deeply since some dynamics on these systems cannot be described by static networks accurately. In this paper, four structural properties in temporal networks are empirically studied, including degree, clustering coefficient, adjacent correlation, and connected component. Three real temporal networks with different time scales are analyzed in this paper, including short message, telephone, and router networks. Moreover, structural properties of these temporal networks are compared with that of corresponding static aggregation networks in the whole time window. Some essential differences of structural properties between temporal and static networks are achieved through empirical analysis. Finally, the effect of structural properties on spreading dynamics under different time scales is investigated. Some interesting results such as turning point of structure evolving time scale corresponding to certain spreading dynamics time scale from the point of view of infected scale are achieved.

  13. Solution Estimates for Semilinear Difference-Delay Equations with Continuous Time

    Directory of Open Access Journals (Sweden)

    Michael Gil'

    2007-01-01

    Full Text Available We consider semilinear difference-delay equations with continuous time in a Euclidean space. Estimates are found for the solutions. Such estimates are then applied to obtain the stability and boundedness criteria for solutions.

  14. Study on the impacts of different time of moxibustion on regulating lipid effects of hyperlipidemia

    Institute of Scientific and Technical Information of China (English)

    陈仲杰

    2013-01-01

    Objective To observe the impacts of different time of moxibustion on its regulating lipid effects and safety of hyperlipidemia. Methods Seventy-six cases of hyperlipi-demia patients were randomly divided into

  15. Towards Real-Time Detection of Gait Events on Different Terrains Using Time-Frequency Analysis and Peak Heuristics Algorithm

    Directory of Open Access Journals (Sweden)

    Hui Zhou

    2016-10-01

    Full Text Available Real-time detection of gait events can be applied as a reliable input to control drop foot correction devices and lower-limb prostheses. Among the different sensors used to acquire the signals associated with walking for gait event detection, the accelerometer is considered as a preferable sensor due to its convenience of use, small size, low cost, reliability, and low power consumption. Based on the acceleration signals, different algorithms have been proposed to detect toe off (TO and heel strike (HS gait events in previous studies. While these algorithms could achieve a relatively reasonable performance in gait event detection, they suffer from limitations such as poor real-time performance and are less reliable in the cases of up stair and down stair terrains. In this study, a new algorithm is proposed to detect the gait events on three walking terrains in real-time based on the analysis of acceleration jerk signals with a time-frequency method to obtain gait parameters, and then the determination of the peaks of jerk signals using peak heuristics. The performance of the newly proposed algorithm was evaluated with eight healthy subjects when they were walking on level ground, up stairs, and down stairs. Our experimental results showed that the mean F1 scores of the proposed algorithm were above 0.98 for HS event detection and 0.95 for TO event detection on the three terrains. This indicates that the current algorithm would be robust and accurate for gait event detection on different terrains. Findings from the current study suggest that the proposed method may be a preferable option in some applications such as drop foot correction devices and leg prostheses.

  16. Preferred time headway in car-following and individual differences in perceptual-motor skills.

    Science.gov (United States)

    van Winsum, W

    1998-12-01

    18 subjects were tested in a simulator to assess whether choice of time headway in car-following is related to individual differences in perceptual-motor skills. Drivers with a larger preferred time headway committed larger steering errors while driving on a winding road and were less accurate in maintaining a constant distance to a lead vehicle that varied its speed between 80 and 100 km/hr. compared to drivers with a smaller preferred time headway. Also, time to collision with the lead vehicle hardly affected the braking response of drivers with a larger preferred time headway. In contrast, the braking response of drivers with a smaller preferred time headway was strongly affected by time to collision with the lead vehicle. The results support the hypothesis that preferred time headway is at least to some extent the result of adaptation to the driver's braking performance and perceptual-motor skills.

  17. Global Uniform Asymptotic Stability of Competitive Neural Networks with Different-Time Scales and Delay

    Institute of Scientific and Technical Information of China (English)

    LI Hong; L(U) Shu; ZHONG Shou-ming

    2005-01-01

    The global uniform asymptotic stability of competitive neural networks with different time scales and delay is investigated. By the method of variation of parameters and the method of inequality analysis, the condition for global uniformly asymptotically stable are given. A strict Lyapunov function for the flow of a competitive neural system with different time scales and delay is presented. Based on the function, the global uniform asymptotic stability of the equilibrium point can be proved.

  18. Minimum Energy Control of Descriptor Fractional Discrete–Time Linear Systems with Two Different Fractional Orders

    Directory of Open Access Journals (Sweden)

    Sajewski Łukasz

    2017-03-01

    Full Text Available Reachability and minimum energy control of descriptor fractional discrete-time linear systems with different fractional orders are addressed. Using the Weierstrass–Kronecker decomposition theorem of the regular pencil, a solution to the state equation of descriptor fractional discrete-time linear systems with different fractional orders is given. The reachability condition of this class of systems is presented and used for solving the minimum energy control problem. The discussion is illustrated with numerical examples.

  19. Time domain analysis for discrete difference equation on discrete linear system controllable problem's research

    Institute of Scientific and Technical Information of China (English)

    DENG Shu-xian; DING Yu; GE Lei

    2008-01-01

    We usually describle a comparatively more complex control system, especially a multi-inputs and multioutputs system by time domation analytical procedure. While the system's controllability means whether the system is controllable according to certain requirements. It involves not only the system's outputs' controllability but also the controllability of the system's partial or total conditions. The movement is described by difference equation in the linear discrete-time system. Therefore, the problem of controllability of the linear discrete-time system has been converted into a problem of the controllability of discrete-time difference equation. The thesis makes out the determination method of the discrete-time system's controllability and puts forward the sufficient and necessary conditions to determine it's controllability by making a study on the controllability of the linear discrete-time equation.

  20. Prefered time headway in car-following and individual differences in perceptual-motor skills

    NARCIS (Netherlands)

    Winsum, W. van

    1999-01-01

    18 Subjects were tested in a simulator to assess whether choice of time headway in car-following is related to individual differences in perceptual-motor skills. Drivers with a larger preferred time headway committed larger steering errors while driving on a winding road and were less accurate in

  1. Preferred time headway in car-following and individual differences in perceptual-motor skills

    NARCIS (Netherlands)

    van Winsum, W

    1998-01-01

    18 subjects were tested in a simulator to assess whether choice of time headway in car-following is related to individual differences in perceptual-motor skills. Drivers with a larger preferred time headway committed larger steering errors while driving on a winding road and were less accurate in

  2. Is networking different with part-time working colleagues? A study of medical teams.

    NARCIS (Netherlands)

    Heiligers, P.; Jong, J. de; Groenewegen, P.; Hingstman, L.

    2007-01-01

    Changes in work arrangements like the introduction of part-time work can affect both formal and informal organization. This study will focus on informal networks amongst teams of medical specialists, some but not all of which include part-time workers. Are there notable differences in the structure

  3. Preferred time headway in car-following and individual differences in perceptual-motor skills

    NARCIS (Netherlands)

    van Winsum, W

    1998-01-01

    18 subjects were tested in a simulator to assess whether choice of time headway in car-following is related to individual differences in perceptual-motor skills. Drivers with a larger preferred time headway committed larger steering errors while driving on a winding road and were less accurate in ma

  4. Prefered time headway in car-following and individual differences in perceptual-motor skills

    NARCIS (Netherlands)

    Winsum, W. van

    1999-01-01

    18 Subjects were tested in a simulator to assess whether choice of time headway in car-following is related to individual differences in perceptual-motor skills. Drivers with a larger preferred time headway committed larger steering errors while driving on a winding road and were less accurate in ma

  5. Time to Maximal Voluntary Isometric Contraction (MVC) for Five Different Muscle Groups in College Adults.

    Science.gov (United States)

    Morris, A. F.; And Others

    1983-01-01

    College men and women were studied to ascertain the force-time components of a rapid voluntary muscle contraction for five muscle groups. Researchers found that the time required for full contraction differs: (1) in men and women; and (2) among the five muscle groups. (Authors/PP)

  6. Time Perception in Severe Traumatic Brain Injury Patients: A Study Comparing Different Methodologies

    Science.gov (United States)

    Mioni, G.; Mattalia, G.; Stablum, F.

    2013-01-01

    In this study, we investigated time perception in patients with traumatic brain injury (TBI). Fifteen TBI patients and 15 matched healthy controls participated in the study. Participants were tested with durations above and below 1s on three different temporal tasks that involved time reproduction, production, and discrimination tasks. Data…

  7. Comparison of Sprint Reaction and Visual Reaction Times of Athletes in Different Branches

    Science.gov (United States)

    Akyüz, Murat; Uzaldi, Basar Basri; Akyüz, Öznur; Dogru, Yeliz

    2017-01-01

    The aims of this study are to analyse sprint reaction and visual reaction times of female athletes of different branches competing in Professional leagues and to show the differences between them. 42 voluntary female athletes from various branches of Professional leagues of Istanbul (volleyball, basketball, handball) were included in the…

  8. Correlation based networks of equity returns sampled at different time horizons

    CERN Document Server

    Tumminello, M; Aste, T; Mantegna, R N

    2006-01-01

    We investigate the planar maximally filtered graphs of the portfolio of the 300 most capitalized stocks traded at the New York Stock Exchange during the time period 2001-2003. Topological properties such as the average length of shortest paths, the betweenness and the degree are investigated on different planar maximally filtered graphs generated by sampling the returns at different time horizons ranging from 5 min up to one trading day. This investigation confirms that the selected stocks compose a hierarchical system progressively structuring as the sampling time horizon increases. Finally, a cluster formation, associated to economic sectors, is quantitatively investigated.

  9. Comparison of different synthetic 5-min rainfall time series regarding their suitability for urban drainage modelling

    Science.gov (United States)

    van der Heijden, Sven; Callau Poduje, Ana; Müller, Hannes; Shehu, Bora; Haberlandt, Uwe; Lorenz, Manuel; Wagner, Sven; Kunstmann, Harald; Müller, Thomas; Mosthaf, Tobias; Bárdossy, András

    2015-04-01

    For the design and operation of urban drainage systems with numerical simulation models, long, continuous precipitation time series with high temporal resolution are necessary. Suitable observed time series are rare. As a result, intelligent design concepts often use uncertain or unsuitable precipitation data, which renders them uneconomic or unsustainable. An expedient alternative to observed data is the use of long, synthetic rainfall time series as input for the simulation models. Within the project SYNOPSE, several different methods to generate synthetic precipitation data for urban drainage modelling are advanced, tested, and compared. The presented study compares four different approaches of precipitation models regarding their ability to reproduce rainfall and runoff characteristics. These include one parametric stochastic model (alternating renewal approach), one non-parametric stochastic model (resampling approach), one downscaling approach from a regional climate model, and one disaggregation approach based on daily precipitation measurements. All four models produce long precipitation time series with a temporal resolution of five minutes. The synthetic time series are first compared to observed rainfall reference time series. Comparison criteria include event based statistics like mean dry spell and wet spell duration, wet spell amount and intensity, long term means of precipitation sum and number of events, and extreme value distributions for different durations. Then they are compared regarding simulated discharge characteristics using an urban hydrological model on a fictitious sewage network. First results show a principal suitability of all rainfall models but with different strengths and weaknesses regarding the different rainfall and runoff characteristics considered.

  10. Blood serum metabolites and meat quality in crossbred pigs experiencing different lairage time

    Directory of Open Access Journals (Sweden)

    Ivan Juric

    2010-01-01

    Full Text Available Pigs of two crosses: A (Duroc x Swedish Landrace x Pietrain (n=24 and B (Swedish Landrace x Large White x Pietrain (n=26 were used to investigate the effects of different lairage time (2 and 24 hours on levels of stress and meat quality traits. No direct effect of lairage time on cortisol, lactate, electrolytes and meat quality parameters was observed. However, after long lairage time, pigs showed lower level of glucose and higher CK, AST and ALT activity. Crossbred B pigs exposed to short lairage time, showed higher blood lactate, sodium, and potassium level, higher drip loss and lower pHi, whereas there were no significant differences between the crossbreeds in the long lairage group. The results indicate that long lairage time decreases blood glucose level and produces signs of muscle damage. In the short lairage period, the crossbreed B showed a higher response to pre-slaughter handling affecting the meat quality.

  11. Effect of different timings of the day on semen and calcium and magnesium in it.

    Science.gov (United States)

    Valsa, James; Skandhan, Kalanghot P; Sumangala, Balakrishnan; Amith, Skandhan; Skandhan Avni, Kalanghot P

    2016-11-18

    The study was conducted to understand the effect of time of the day on semen parameters as well as on the level of two electrolytes, calcium and magnesium, in it. A total number of 27 normal healthy adults submitted 156 ejaculates during six different fixed timings of the day on six different occasions. A significant observation was that semen quality was superior in terms of total sperm count percentage and active motility at 0000 hours. A second peak was seen at 0800 hours. Calcium and magnesium level in seminal plasma was maximum at 0000 hours. No significant difference was observed in case of spermatozoa elements among different timings. The study showed that probably the release as well as the quality of sample was dependent on blood androgen.

  12. Separating timing, movement conditions and individual differences in the analysis of human movement

    DEFF Research Database (Denmark)

    Raket, Lars Lau; Grimme, Britta; Schöner, Gregor

    2016-01-01

    A central task in the analysis of human movement behavior is to determine systematic patterns and differences across experimental conditions, participants and repetitions. This is possible because human movement is highly regular, being constrained by invariance principles. Movement timing......-effects model for analyzing temporally continuous signals that contain systematic effects in both timing and path. Identifiability issues of path relative to timing are overcome by using maximum likelihood estimation in which the most likely separation of space and time is chosen given the variation found...

  13. Finite-time stochastic outer synchronization between two complex dynamical networks with different topologies.

    Science.gov (United States)

    Sun, Yongzheng; Li, Wang; Zhao, Donghua

    2012-06-01

    In this paper, the finite-time stochastic outer synchronization between two different complex dynamical networks with noise perturbation is investigated. By using suitable controllers, sufficient conditions for finite-time stochastic outer synchronization are derived based on the finite-time stability theory of stochastic differential equations. It is noticed that the coupling configuration matrix is not necessary to be symmetric or irreducible, and the inner coupling matrix need not be symmetric. Finally, numerical examples are examined to illustrate the effectiveness of the analytical results. The effect of control parameters on the settling time is also numerically demonstrated.

  14. A rapid reflectance-difference spectrometer for real-time semiconductor growth monitoring with sub-second time resolution.

    Science.gov (United States)

    Núñez-Olvera, O; Balderas-Navarro, R E; Ortega-Gallegos, J; Guevara-Macías, L E; Armenta-Franco, A; Lastras-Montaño, M A; Lastras-Martínez, L F; Lastras-Martínez, A

    2012-10-01

    We report on a rapid, 32-channel reflectance-difference (RD) spectrometer with sub-second spectra acquisition times and ΔR/R sensitivity in the upper 10(-4) range. The spectrometer is based on a 50 kHz photo-elastic modulator for light polarization modulation and on a lock-in amplifier for signal harmonic analysis. Multichannel operation is allowed by multiplexing the 32 outputs of the spectrometer into the input of the lock-in amplifier. The spectrometer spans a wavelength range of 230 nm that can be tuned to cover E(1) and E(1) + Δ(1) transitions for a number of III-V semiconductors at epitaxial growth temperatures, including GaAs, InAs, AlAs, and their alloys. We present two examples of real-time measurements to demonstrate the performance of the RD spectrometer, namely, the evolution of the RD spectrum of GaAs (001) annealed at 500 °C and the time-dependent RD spectrum during the first stages of the epitaxial growth of In(0.3)Ga(0.7)As on GaAs (001) substrates.

  15. Contributed Review: Source-localization algorithms and applications using time of arrival and time difference of arrival measurements

    Science.gov (United States)

    Li, Xinya; Deng, Zhiqun Daniel; Rauchenstein, Lynn T.; Carlson, Thomas J.

    2016-04-01

    Locating the position of fixed or mobile sources (i.e., transmitters) based on measurements obtained from sensors (i.e., receivers) is an important research area that is attracting much interest. In this paper, we review several representative localization algorithms that use time of arrivals (TOAs) and time difference of arrivals (TDOAs) to achieve high signal source position estimation accuracy when a transmitter is in the line-of-sight of a receiver. Circular (TOA) and hyperbolic (TDOA) position estimation approaches both use nonlinear equations that relate the known locations of receivers and unknown locations of transmitters. Estimation of the location of transmitters using the standard nonlinear equations may not be very accurate because of receiver location errors, receiver measurement errors, and computational efficiency challenges that result in high computational burdens. Least squares and maximum likelihood based algorithms have become the most popular computational approaches to transmitter location estimation. In this paper, we summarize the computational characteristics and position estimation accuracies of various positioning algorithms. By improving methods for estimating the time-of-arrival of transmissions at receivers and transmitter location estimation algorithms, transmitter location estimation may be applied across a range of applications and technologies such as radar, sonar, the Global Positioning System, wireless sensor networks, underwater animal tracking, mobile communications, and multimedia.

  16. The impact of different prioritisation policies on waiting times: case studies of Norway and Scotland.

    Science.gov (United States)

    Januleviciute, Jurgita; Askildsen, Jan Erik; Kaarboe, Oddvar; Holmås, Tor Helge; Sutton, Matt

    2013-11-01

    We investigate the distributional consequences of two different waiting times initiatives, one in Norway, and one in Scotland. The primary focus of Scotland's recent waiting time reforms, introduced in 2003, and modified in 2005 and 2007, has been on reducing maximum waiting times through the imposition of high profile national targets accompanied by increases in resources. In Norway, the focus of the reform introduced in September 2004, has been on assigning patients referred to hospital a maximum waiting time based on disease severity, the expected benefit and the cost-effectiveness of the treatment. We use large, national administrative datasets from before and after each of these reforms and assign priority groups based on the maximum waiting times stipulated in medical guidelines. The analysis shows that the lowest priority patients benefited most from both reforms. This was at the cost of longer waiting times for patients that should have been given higher priority in Norway, while Scotland's high priority patients remained unaffected.

  17. Regional differences in time to pregnancy among fertile women from five Colombian regions with different use of glyphosate.

    Science.gov (United States)

    Sanin, Luz-Helena; Carrasquilla, Gabriel; Solomon, Keith R; Cole, Donald C; Marshall, E J P

    2009-01-01

    The objective of this study was to test whether there was an association between the use of glyphosate when applied by aerial spray for the eradication of illicit crops (cocaine and poppy) and time to pregnancy (TTP) among fertile women. A retrospective cohort study (with an ecological exposure index) of first pregnancies was undertaken in 2592 fertile Colombian women from 5 regions with different uses of glyphosate. Women were interviewed regarding potential reproductive, lifestyle, and work history predictors of TTP, which was measured in months. Fecundability odds ratios (fOR) were estimated using a discrete time analogue of Cox's proportional hazard model. There were differences in TTP between regions. In the final multivariate model, the main predictor was the region adjusted by irregular relationship with partner, maternal age at first pregnancy, and, marginally, coffee consumption and self-perception of water pollution. Boyaca, a region with traditional crops and. recently, illicit crops without glyphosate eradication spraying (manual eradication), displayed minimal risk and was the reference region. Other regions, including Sierra Nevada (control area, organic agriculture), Putumayo and Narino (illicit crops and intensive eradication spray program), and Valle del Cauca, demonstrated greater risk of longer TTP, with the highest risk for Valle del Cauca (fOR 0.15, 95% CI 0.12, 0.18), a sugar-cane region with a history of use of glyphosate and others chemicals for more than 30 yr. The reduced fecundability in some regions was not associated with the use of glyphosate for eradication spraying. The observed ecological differences remain unexplained and may be produced by varying exposures to environmental factors, history of contraceptive programs in the region, or psychological distress. Future studies examining these or other possible causes are needed.

  18. Optimizing the train timetable with consideration of different kinds of headway time

    Directory of Open Access Journals (Sweden)

    Pei Liu

    2017-06-01

    Full Text Available The train timetable is a crucial document for organization of railway traffic. A high-quality train timetable is not only implementable in operational environment, but also efficient in terms of capacity utilization of railway infrastructure. In this paper, we try to solve the train timetabling problem of a double track high-speed railway line with heavy traffic and trains with different operational speeds are operated. In order to obtain a feasible timetable with high efficiency, different kinds of headway time are distinguished in the process of train timetabling. With a time expanded graph describing train movements, an integer linear programming is formulated. A branch and price algorithm is proposed to solve the model. The case study shows that more trains will be scheduled when different kinds of headway time considered.

  19. Data on noise environments at different times of day around airports

    Science.gov (United States)

    Fields, J. M.

    1985-01-01

    Sources of information about noise environments at different times of the day at civilian and military airports are identified. Information about movements of scheduled flights are available in machine readable form from the Official Airline Guide. Information about permanent noise monitoring sites is readily obtained from individual airports. Limited data on the timing of flights are available at centralized locations for military airports. An examination of scheduled flights at commercial airports leads to the conclusion that differences between daytime and nighttime noise levels (measured in Equivalent Continuous Noise Level, LEQ) vary from 7 to 15 decibels. Data from 128 permanent noise monitoring sites at 11 airports are also examined. Differences between daytime and nighttime noise levels at these 128 noise monitoring sites vary from 3 to 17 decibels (LEQ). Preliminary analyses suggest that accurate estimates of time-of-day weights could not be obtained from conventional social surveys at existing airports.

  20. Preconditioned time-difference methods for advection-diffusion-reaction equations

    Energy Technology Data Exchange (ETDEWEB)

    Aro, C.; Rodrigue, G. [Lawrence Livermore National Lab., CA (United States); Wolitzer, D. [California State Univ., Hayward, CA (United States)

    1994-12-31

    Explicit time differencing methods for solving differential equations are advantageous in that they are easy to implement on a computer and are intrinsically very parallel. The disadvantage of explicit methods is the severe restrictions placed on stepsize due to stability. Stability bounds for explicit time differencing methods on advection-diffusion-reaction problems are generally quite severe and implicit methods are used instead. The linear systems arising from these implicit methods are large and sparse so that iterative methods must be used to solve them. In this paper the authors develop a methodology for increasing the stability bounds of standard explicit finite differencing methods by combining explicit methods, implicit methods, and iterative methods in a novel way to generate new time-difference schemes, called preconditioned time-difference methods.

  1. Sex differences in time to task failure during early pubertal development.

    Science.gov (United States)

    Rudroff, Thorsten; Holmes, Matthew R; Melanson, Edward L; Kelsey, Megan M

    2014-06-01

    We compared fatigability and activation of elbow flexor muscles in children at 3 pubertal stages during a sustained submaximal contraction. In 72 healthy children (39 boys) aged 11 ± 3 years (range, 8-14 years), differences in fatigability (time to task failure) and muscle activation were compared at 3 Tanner stages (T1-T3). Time to task failure and muscle activation were similar between boys and girls at prepubertal Tanner stage 1. Time to task failure was briefer for girls than boys at Tanner stages 2 and 3 and was predicted by the coactivation indices and percent body fat in girls. Muscle torque was the only predictor for the time to task failure in boys. Differences in fatigability and muscle coactivation were evident during the initial pubertal stages (T2 and T3), but not before the onset of puberty (T1). Copyright © 2013 Wiley Periodicals, Inc.

  2. Difference in peak weight transfer and timing based on golf handicap.

    Science.gov (United States)

    Queen, Robin M; Butler, Robert J; Dai, Boyi; Barnes, C Lowry

    2013-09-01

    Weight shift during the golf swing has been a topic of discussion among golf professionals; however, it is still unclear how weight shift varies in golfers of different performance levels. The main purpose of this study was to examine the following: (a) the changes in the peak ground reaction forces (GRF) and the timing of these events between high (HHCP) and low handicap (LHCP) golfers and (b) the differences between the leading and trailing legs. Twenty-eight male golfers were recruited and divided based on having an LHCP 9. Three-dimensional GRF peaks and the timing of the peaks were recorded bilaterally during a golf swing. The golf swing was divided into different phases: (a) address to the top of the backswing, (b) top of the backswing to ball contact, and (c) ball contact to the end of follow through. Repeated measures analyses of variance (α = 0.05) were completed for each study variable: the magnitude and the timing of peak vertical GRF, peak lateral GRF, and peak medial GRF (α = 0.05). The LHCP group had a greater transfer of vertical force from the trailing foot to the leading foot in phase 2 than the HHCP group. The LHCP group also demonstrated earlier timing of peak vertical force throughout the golf swing than the HHCP group. The LHCP and HHCP groups demonstrated different magnitudes of peak lateral force. The LHCP group had an earlier timing of peak lateral GRF in phase 2 and earlier timing of peak medial GRF in phases 1 and 2 than the HHCP group. In general, LHCP golfers demonstrated greater and earlier force generation than HHCP golfers. It may be relevant to consider both the magnitude of the forces and the timing of these events during golf-specific training to improve performance. These data reveal weight shifting differences that can be addressed by teaching professionals to help their students better understand weight transfer during the golf swing to optimize performance.

  3. Arrival Time Differences between Gravitational Waves and Electromagnetic Signals due to Gravitational Lensing

    Science.gov (United States)

    Takahashi, Ryuichi

    2017-01-01

    In this study we demonstrate that general relativity predicts arrival time differences between gravitational wave (GW) and electromagnetic (EM) signals caused by the wave effects in gravitational lensing. The GW signals can arrive earlier than the EM signals in some cases if the GW/EM signals have passed through a lens, even if both signals were emitted simultaneously by a source. GW wavelengths are much larger than EM wavelengths; therefore, the propagation of the GWs does not follow the laws of geometrical optics, including the Shapiro time delay, if the lens mass is less than approximately 105 M⊙(f/Hz)‑1, where f is the GW frequency. The arrival time difference can reach ∼0.1 s (f/Hz)‑1 if the signals have passed by a lens of mass ∼8000 M⊙(f/Hz)‑1 with the impact parameter smaller than the Einstein radius; therefore, it is more prominent for lower GW frequencies. For example, when a distant supermassive black hole binary (SMBHB) in a galactic center is lensed by an intervening galaxy, the time lag becomes of the order of 10 days. Future pulsar timing arrays including the Square Kilometre Array and X-ray detectors may detect several time lags by measuring the orbital phase differences between the GW/EM signals in the SMBHBs. Gravitational lensing imprints a characteristic modulation on a chirp waveform; therefore, we can deduce whether a measured arrival time lag arises from intrinsic source properties or gravitational lensing. Determination of arrival time differences would be extremely useful in multimessenger observations and tests of general relativity.

  4. A conversion formula for comparing pulse oximeter desaturation rates obtained with different averaging times.

    Directory of Open Access Journals (Sweden)

    Jan Vagedes

    Full Text Available OBJECTIVE: The number of desaturations determined in recordings of pulse oximeter saturation (SpO2 primarily depends on the time over which values are averaged. As the averaging time in pulse oximeters is not standardized, it varies considerably between centers. To make SpO2 data comparable, it is thus desirable to have a formula that allows conversion between desaturation rates obtained using different averaging times for various desaturation levels and minimal durations. METHODS: Oxygen saturation was measured for 170 hours in 12 preterm infants with a mean number of 65 desaturations <90% per hour of arbitrary duration by using a pulse oximeter in a 2-4 s averaging mode. Using 7 different averaging times between 3 and 16 seconds, the raw red-to-infrared data were reprocessed to determine the number of desaturations (D. The whole procedure was carried out for 7 different minimal desaturation durations (≥ 1, ≥ 5, ≥ 10, ≥ 15, ≥ 20, ≥ 25, ≥ 30 s below SpO2 threshold values of 80%, 85% or 90% to finally reach a conversion formula. The formula was validated by splitting the infants into two groups of six children each and using one group each as a training set and the other one as a test set. RESULTS: Based on the linear relationship found between the logarithm of the desaturation rate and the logarithm of the averaging time, the conversion formula is: D2 = D1 (T2/T1(c, where D2 is the desaturation rate for the desired averaging time T2, and D1 is the desaturation rate for the original averaging time T1, with the exponent c depending on the desaturation threshold and the minimal desaturation duration. The median error when applying this formula was 2.6%. CONCLUSION: This formula enables the conversion of desaturation rates between different averaging times for various desaturation thresholds and minimal desaturation durations.

  5. [Analysis on therapeutic effects of different acupuncture times on peripheral facial paralysis].

    Science.gov (United States)

    Shui, Su-hua

    2006-02-01

    To observe clinical therapeutic effects of different acupuncture times on peripheral facial paralysis. Forty-nine cases of peripheral facial paralysis were randomly divided into 2 groups, group A and B. The group A received acupuncture, once daily, and the group B twice each week. Their therapeutic effects were assessed after 3 courses. The acupuncture times were not direct proportion to the therapeutic effect (P0.05). Acupuncture treatment can select twice each week for peripheral facial paralysis.

  6. The Impact of Time Difference between Satellite Overpass and Ground Observation on Cloud Cover Performance Statistics

    Directory of Open Access Journals (Sweden)

    Jędrzej S. Bojanowski

    2014-12-01

    Full Text Available Cloud property data sets derived from passive sensors onboard the polar orbiting satellites (such as the NOAA’s Advanced Very High Resolution Radiometer have global coverage and now span a climatological time period. Synoptic surface observations (SYNOP are often used to characterize the accuracy of satellite-based cloud cover. Infrequent overpasses of polar orbiting satellites combined with the 3- or 6-h SYNOP frequency lead to collocation time differences of up to 3 h. The associated collocation error degrades the cloud cover performance statistics such as the Hanssen-Kuiper’s discriminant (HK by up to 45%. Limiting the time difference to 10 min, on the other hand, introduces a sampling error due to a lower number of corresponding satellite and SYNOP observations. This error depends on both the length of the validated time series and the SYNOP frequency. The trade-off between collocation and sampling error call for an optimum collocation time difference. It however depends on cloud cover characteristics and SYNOP frequency, and cannot be generalized. Instead, a method is presented to reconstruct the unbiased (true HK from HK affected by the collocation differences, which significantly (t-test p < 0.01 improves the validation results.

  7. Introduction to the Finite-Difference Time-Domain (FDTD) Method for Electromagnetics

    CERN Document Server

    Gedney, Stephen

    2011-01-01

    Introduction to the Finite-Difference Time-Domain (FDTD) Method for Electromagnetics provides a comprehensive tutorial of the most widely used method for solving Maxwell's equations -- the Finite Difference Time-Domain Method. This book is an essential guide for students, researchers, and professional engineers who want to gain a fundamental knowledge of the FDTD method. It can accompany an undergraduate or entry-level graduate course or be used for self-study. The book provides all the background required to either research or apply the FDTD method for the solution of Maxwell's equations to p

  8. The effects of different application time on all-in-one self-etching adhesives

    OpenAIRE

    Feng, Pan; Afm, Almas Chowdhury; Shihchun, Ting; Shinichi, Kakuda; Shuhei, Hoshika; Yasuhiro, Matsuda; Takatsumi, Ikeda; Hidehiko, Sano

    2015-01-01

    The purpose of this study was to evaluate the effects of different application times in all-in-one systems on micro-tensile bond strength. Three all-in-one systems, EB (Easy Bond, 3M ESPE, St. Paul, MN, USA), BB (BeautiBond, Shofu Inc., Japan) and BF (BondForce, Tokuyama Denetal, Ibaraki, Japan)were used with four different application times: 10s, 20s, 30s, and 40s. Bond strengths to dentin were determined using μTBS test after 24h of water storage at 37℃. In addition, an evaluation of both r...

  9. Weighted permutation entropy based on different symbolic approaches for financial time series

    Science.gov (United States)

    Yin, Yi; Shang, Pengjian

    2016-02-01

    In this paper, we introduce weighted permutation entropy (WPE) and three different symbolic approaches to investigate the complexities of stock time series containing amplitude-coded information and explore the influence of using different symbolic approaches on obtained WPE results. We employ WPE based on symbolic approaches to the US and Chinese stock markets and make a comparison between the results of US and Chinese stock markets. Three symbolic approaches are able to help the complexity containing in the stock time series by WPE method drop whatever the embedding dimension is. The similarity between these stock markets can be detected by the WPE based on Binary Δ-coding-method, while the difference between them can be revealed by the WPE based on σ-method, Max-min-method. The combinations of the symbolic approaches: σ-method and Max-min-method, and WPE method are capable of reflecting the multiscale structure of complexity by different time delay and analyze the differences between complexities of stock time series in more detail and more accurately. Furthermore, the correlations between stock markets in the same region and the similarities hidden in the S&P500 and DJI, ShangZheng and ShenCheng are uncovered by the comparison of the WPE based on Binary Δ-coding-method of six stock markets.

  10. Practical stability with respect to initial time difference for Caputo fractional differential equations

    Science.gov (United States)

    Agarwal, Ravi; O'Regan, D.; Hristova, S.; Cicek, M.

    2017-01-01

    Practical stability with initial data difference for nonlinear Caputo fractional differential equations is studied. This type of stability generalizes known concepts of stability in the literature. It enables us to compare the behavior of two solutions when both initial values and initial intervals are different. In this paper the concept of practical stability with initial time difference is generalized to Caputo fractional differential equations. A definition of the derivative of Lyapunov like function along the given nonlinear Caputo fractional differential equation is given. Comparison results using this definition and scalar fractional differential equations are proved. Sufficient conditions for several types of practical stability with initial time difference for nonlinear Caputo fractional differential equations are obtained via Lyapunov functions. Some examples are given to illustrate the results.

  11. Total Field and Scattered Field Technique for Fourth-Order Symplectic Finite Difference Time Domain Method

    Institute of Scientific and Technical Information of China (English)

    SHA Wei; HUANG Zhi-Xiang; WU Xian-Liang; CHEN Ming-Sheng

    2006-01-01

    Using symplectic integrator propagator, a three-dimensional fourth-order symplectic finite difference time domain (SFDTD) method is studied, which is of the fourth order in both the time and space domains. The method is nondissipative and can save more memory compared with the traditional FDTD method. The total field and scattered field (TF-SF) technique is derived for the SFDTD method to provide the incident wave source conditions. The bistatic radar cross section (RCS) of a dielectric sphere is computed by using the SFDTD method for the first time. Numerical results suggest that the SFDTD algorithm acquires better stability and accuracy compared with the traditional FDTD method.

  12. Simulation of acoustic streaming by means of the finite-difference time-domain method

    DEFF Research Database (Denmark)

    Santillan, Arturo Orozco

    2012-01-01

    the finite-difference time-domain method. To simplify the problem, thermal effects are not considered. The motivation of the described investigation has been the possibility of using the numerical method to study acoustic streaming, particularly under non-steady conditions. Results are discussed for channels...... of different width, which illustrate the applicability of the method. The obtained numerical simulations agree quite will with analytical solutions available in the literature....

  13. Taylor polynomial solution of difference equation with constant coefficients via time scales calculus

    Directory of Open Access Journals (Sweden)

    Veysel Hatipoglu

    2015-09-01

    Full Text Available In this study, we present a practical matrix method to find an approximate solution of higher order linear difference equation with constant coefficients under the initial-boundary conditions in terms of Taylor polynomials. To obtain this goal, we first present time scale extension of previous polynomial approach, then restrict the formula to the Integers with h step. This method converts the difference equation to a matrix equation, which may be considered as a system of linear algebraic equations.

  14. Yield and crop cycle time of peaches cultivated in subtropical climates and subjected to different pruning times

    Directory of Open Access Journals (Sweden)

    Rafael Augusto Ferraz

    2015-12-01

    Full Text Available The cultivation of peaches in regions of subtropical and tropical climate is currently achieved through a set of practices such as using less demanding cultivars in cold conditions, applying plant growth regulators to break dormancy, and performing specific pruning, like production and renewal pruning. Research on the climate adaptation of cultivars is of great importance in establishing a crop in a given region. Therefore, the objective of this study was to evaluate the agronomic performance of three cultivars subjected to different production pruning times in Botucatu/SP, where 2-year old peach trees were evaluated, grown at a spacing of 6.0 x 4.0 meters. The experimental design was a split plot design with four blocks, using the cultivars Douradão, BRS Kampai and BRS Rubimel, and the subplots corresponded to pruning times in May, June, July and August. Ten plants were used per plot, with the four central plants considered useful and the remaining considered as margins. Pruning in June and July showed the best results in terms of percentage of fruit set and production. The cultivar BRS Rubimel showed the best percentage of fruit set when pruned in June (44.96%, and best fruit production when pruned in July (18.7 kg plant-1. Pruning in May anticipated the harvest of cultivar BRS Rubimel by 13 days whereas pruning carried out in July and August provided late harvests for cultivars Douradão and BRS Kampai.

  15. Contributed Review: Source-localization algorithms and applications using time of arrival and time difference of arrival measurements

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xinya [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Deng, Zhiqun Daniel [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Rauchenstein, Lynn T. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Carlson, Thomas J. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA

    2016-04-01

    Locating the position of fixed or mobile sources (i.e., transmitters) based on received measurements from sensors is an important research area that is attracting much research interest. In this paper, we present localization algorithms using time of arrivals (TOA) and time difference of arrivals (TDOA) to achieve high accuracy under line-of-sight conditions. The circular (TOA) and hyperbolic (TDOA) location systems both use nonlinear equations that relate the locations of the sensors and tracked objects. These nonlinear equations can develop accuracy challenges because of the existence of measurement errors and efficiency challenges that lead to high computational burdens. Least squares-based and maximum likelihood-based algorithms have become the most popular categories of location estimators. We also summarize the advantages and disadvantages of various positioning algorithms. By improving measurement techniques and localization algorithms, localization applications can be extended into the signal-processing-related domains of radar, sonar, the Global Positioning System, wireless sensor networks, underwater animal tracking, mobile communications, and multimedia.

  16. Influence of different anoxic time exposures on active biomass, protozoa and filamentous bacteria in activated sludge.

    Science.gov (United States)

    Rodriguez-Perez, S; Fermoso, F G; Arnaiz, C

    Medium-sized wastewater treatment plants are considered too small to implement anaerobic digestion technologies and too large for extensive treatments. A promising option as a sewage sludge reduction method is the inclusion of anoxic time exposures. In the present study, three different anoxic time exposures of 12, 6 and 4 hours have been studied to reduce sewage sludge production. The best anoxic time exposure was observed under anoxic/oxic cycles of 6 hours, which reduced 29.63% of the biomass production compared with the oxic control conditions. The sludge under different anoxic time exposures, even with a lower active biomass concentration than the oxic control conditions, showed a much higher metabolic activity than the oxic control conditions. Microbiological results suggested that both protozoa density and abundance of filamentous bacteria decrease under anoxic time exposures compared to oxic control conditions. The anoxic time exposures 6/6 showed the highest reduction in both protozoa density, 37.5%, and abundance of filamentous bacteria, 41.1%, in comparison to the oxic control conditions. The groups of crawling ciliates, carnivorous ciliates and filamentous bacteria were highly influenced by the anoxic time exposures. Protozoa density and abundance of filamentous bacteria have been shown as promising bioindicators of biomass production reduction.

  17. Biliary tract injury caused by different relative warm ischemia time in liver transplantation in rats

    Institute of Scientific and Technical Information of China (English)

    Hong-Feng Zhao; Guo-Wei Zhang; Jie Zhou; Jian-Hua Lin; Zhong-Lin Cui; Xiang-Hong Li

    2009-01-01

    BACKGROUND: There is a controversy over the degree of liver and biliary injury caused by the period of secondary warm ischemia. A liver autotransplantation model was adopted because it excludes the effects of infection and immunological rejection on bile duct injury. This study was undertaken to assess biliary tract injury caused by relative warm ischemia (secondary warm ischemia time in the biliary tract) and reperfusion. METHODS: One hundred and two rats were randomly divided into 5 groups: groupⅠ (control); groupsⅡ toⅤ, relative warm ischemia times of 0 minute, 30 minutes, 1 hour and 2 hours. In addition to the levels of serum alkaline phosphatase, and total bilirubin, pathomorphology assessment and TUNEL assay were performed to evaluate biliary tract damage. RESULTS: Under the conditions that there were no signiifcant differences in warm ischemia time, cold perfusion time and anhepatic phase, group comparisons showed statistically signiifcant differences. The least injury occurred in groupⅡ (portal vein and hepatic artery reperfused simultaneously) but the most severe injury occurred in groupⅤ (biliary tract relative warm ischemia time 2 hours). CONCLUSIONS: Relative warm ischemia is one of the factors that result in bile duct injury, and the relationship between relative warm ischemia time the bile injury degree is time-dependent. Simultaneous arterial and portal reperfusion is the best choice to avoid the bile duct injury caused by relative warm ischemia.

  18. Sex differences in accuracy and precision when judging time to arrival: data from two Internet studies.

    Science.gov (United States)

    Sanders, Geoff; Sinclair, Kamila

    2011-12-01

    We report two Internet studies that investigated sex differences in the accuracy and precision of judging time to arrival. We used accuracy to mean the ability to match the actual time to arrival and precision to mean the consistency with which each participant made their judgments. Our task was presented as a computer game in which a toy UFO moved obliquely towards the participant through a virtual three-dimensional space on route to a docking station. The UFO disappeared before docking and participants pressed their space bar at the precise moment they thought the UFO would have docked. Study 1 showed it was possible to conduct quantitative studies of spatiotemporal judgments in virtual reality via the Internet and confirmed reports that men are more accurate because women underestimate, but found no difference in precision measured as intra-participant variation. Study 2 repeated Study 1 with five additional presentations of one condition to provide a better measure of precision. Again, men were more accurate than women but there were no sex differences in precision. However, within the coincidence-anticipation timing (CAT) literature, of those studies that report sex differences, a majority found that males are both more accurate and more precise than females. Noting that many CAT studies report no sex differences, we discuss appropriate interpretations of such null findings. While acknowledging that CAT performance may be influenced by experience we suggest that the sex difference may have originated among our ancestors with the evolutionary selection of men for hunting and women for gathering.

  19. The difference is in the start: impact of timing and start procedure on sprint running performance.

    Science.gov (United States)

    Haugen, Thomas A; Tønnessen, Espen; Seiler, Stephen K

    2012-02-01

    The difference is in the start: impact of timing and start procedure on sprint running performance. The purpose of this study was to compare different sprint start positions and to generate correction factors between popular timing triggering methods on 40-m/40-yd sprint time. Fourteen female athletes (17 ± 1 years), personal best 100 m: 13.26 (±0.68) seconds and 11 male athletes (20 ± 5 years), personal best 100 m: 11.58 (±0.74) seconds participated. They performed 2 series of 3 40-m sprints in randomized order: (a) start from the block, measured by means of Brower audio sensor (BAS) and Dartfish video timing (DVT), (b) 3-point start, measured by using hand release pod (HR) and DVT, and (c) standing start, triggered by both photocell across starting line (SFC), and foot release (FR) plus DVT. Video analysis was performed by 2 independent observers and averaged. Simultaneous measurements at national athletics competitions demonstrated that DVT and BAS were equivalent to Omega Timing within the limits of precision of video timing (±0.01 seconds). Hand and floor timer triggering showed small but significant biases compared with movement captured from video (0.02-0.04 seconds), presumably because of sensitivity of pressure thresholds. Coefficient of variation for test-retest timing using different starting positions ranged from 0.7 to 1.0%. Compared with block starts reacting to gunfire, HR, SFC, and FR starts yielded 0.17 ± 0.09, 0.27 ± 0.12, and 0.69 ± 0.11 second faster times, respectively, over 40 m (all p sprint performances.

  20. Stability with respect to initial time difference for generalized delay differential equations

    Directory of Open Access Journals (Sweden)

    Ravi Agarwal

    2015-02-01

    Full Text Available Stability with initial data difference for nonlinear delay differential equations is introduced. This type of stability generalizes the known concept of stability in the literature. It gives us the opportunity to compare the behavior of two nonzero solutions when both initial values and initial intervals are different. Several sufficient conditions for stability and for asymptotic stability with initial time difference are obtained. Lyapunov functions as well as comparison results for scalar ordinary differential equations are employed. Several examples are given to illustrate the theory.

  1. Global generalized synchronization in networks of different time-delay systems

    Science.gov (United States)

    Senthilkumar, D. V.; Suresh, R.; Lakshmanan, M.; Kurths, J.

    2013-09-01

    We show that global generalized synchronization (GS) exists in structurally different time-delay systems, even with different orders, with quite different fractal (Kaplan-Yorke) dimensions, which emerges via partial GS in symmetrically coupled regular networks. We find that there exists a smooth transformation in such systems, which maps them to a common GS manifold as corroborated by their maximal transverse Lyapunov exponent. In addition, an analytical stability condition using the Krasvoskii-Lyapunov theory is deduced. This phenomenon of GS in strongly distinct systems opens a new way for an effective control of pathological synchronous activity by means of extremely small perturbations to appropriate variables in the synchronization manifold.

  2. A Normalized Difference Vegetation Index (NDVI Time-Series of Idle Agriculture Lands: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Andrew K Skidmore

    2011-01-01

    Full Text Available In this paper, the NDVI time-series collected from the study area between year 2003 and 2005 of all land cover types are plotted and compared. The study area is the agricultural zones in Banphai District, Khonkean, Thailand. The LANDSAT satellite images of different dates were first transformed into a time series of Normalized Difference Vegetation Index (NDVI images before the investigation. It can be visually observed that the NDVI time series of the Idle Agriculture Land (IAL has the NDVI values closed to zero. In other words, the trend of the NDVI values remains, approximately, unchanged about the zero level for the whole period of the study time. In contrast, the non-idle areas hold a higher level of the NDVI variation. The NDVI values above 0.5 can be found in these non-idle areas during the growing seasons. Thus, it can be hypothesized that the NDVI time-series of the different land cover types can be used for IAL classification. This outcome is a prerequisite to the follow-up study of the NDVI pattern classification that will be done in the near future.

  3. A comparison of different ways to approximate time-to-line crossing (TLC) during car driving

    NARCIS (Netherlands)

    van Winsum, W; Brookhuis, KA; de Waard, D

    2000-01-01

    Three experiments are presented: in which the accuracy of different methods to approximate time-to-line crossing is assessed. In the first experiment TLC was computed, using a trigonometric method, during normal driving while the vehicle stayed in lane. The minima of TLC were compared with two appro

  4. The finite difference time domain method on a massively parallel computer

    NARCIS (Netherlands)

    Ewijk, L.J. van

    1996-01-01

    At the Physics and Electronics Laboratory TNO much research is done in the field of computational electromagnetics (CEM). One of the tools in this field is the Finite Difference Time Domain method (FDTD), a method that has been implemented in a program in order to be able to compute electromagnetic

  5. Finite-difference time domain solution of light scattering by arbitrarily shaped particles and surfaces

    DEFF Research Database (Denmark)

    Tanev, Stoyan; Sun, Wenbo

    2012-01-01

    This chapter reviews the fundamental methods and some of the applications of the three-dimensional (3D) finite-difference time-domain (FDTD) technique for the modeling of light scattering by arbitrarily shaped dielectric particles and surfaces. The emphasis is on the details of the FDTD algorithms...

  6. Finite-difference, spectral and Galerkin methods for time-dependent problems

    Science.gov (United States)

    Tadmor, E.

    1983-01-01

    Finite difference, spectral and Galerkin methods for the approximate solution of time dependent problems are surveyed. A unified discussion on their accuracy, stability and convergence is given. In particular, the dilemma of high accuracy versus stability is studied in some detail.

  7. Viability of lymphocyte culture, at different times after blood collection, for karyotype analysis

    Directory of Open Access Journals (Sweden)

    Ligia Maria Crubelati Bulla

    2014-04-01

    Full Text Available Introduction:Cytogenetics is the area of genetics that studies chromosomes, including numerical changes, and their relationship to structural imbalances. Among the classical cytogenetics tests, the GTG banding karyotype is the most widely used. The period of culture establishment is a critical step, which can affect the pre-analytical phase of the test.Objective:To evaluate, at different establishment times, culture viability and banding resolution.Material and methods:Collection of 10 ml blood from 10 subjects was carried out for culture analysis. For viability analysis, mitotic index (MI and banding resolution were assessed. Results: The comparative analysis of MI showed significant difference between times. In the assessment of banding resolution, the mean value of the bands was higher at times zero and 24 hour.Discussion:The MI reflects inhibition of cell cycle progression and/or loss of ability to proliferate. When the pair analysis was performed, a difference between zero and 48 hours was observed. The average number of bands analyzed at times zero and 24 hours did not indicate difference in the quantity and quality of the bands when cultures were grown immediately after blood collection or within 24 hours. At the 48th hour after blood collection significant reduction of band resolution was observed.Conclusion:These data highlight the importance of the biological material quality, as viability is lower when the culture is grown after 24 hours, as well as the banding resolution.

  8. Correlates of sedentary time in different age groups: results from a large cross sectional Dutch survey

    NARCIS (Netherlands)

    Bernaards, C.; Hildebrandt, V.H.; Hendriksen, I.J.

    2016-01-01

    Background. Evidence shows that prolonged sitting is associated with an increased risk of mortality, independent of physical activity (PA). The aim of the study was to identify correlates of sedentary time (ST) in different age groups and day types (i.e. school-/work day versus non-school-/non-work

  9. Finite difference time domain modeling of light matter interaction in light-propelled microtools

    DEFF Research Database (Denmark)

    Bañas, Andrew Rafael; Palima, Darwin; Aabo, Thomas

    2013-01-01

    may trigger highly localized non linear processes in the surface of a cell. Since these functionalities are strongly dependent on design, it is important to use models that can handle complexities and take in little simplifying assumptions about the system. Hence, we use the finite difference time...

  10. Analysis of oscillational instabilities in acoustic levitation using the finite-difference time-domain method

    DEFF Research Database (Denmark)

    Santillan, Arturo Orozco

    2011-01-01

    The aim of the work described in this paper has been to investigate the use of the finite-difference time-domain method to describe the interactions between a moving object and a sound field. The main objective was to simulate oscillational instabilities that appear in single-axis acoustic...

  11. Finite-difference time domain solution of light scattering by arbitrarily shaped particles and surfaces

    DEFF Research Database (Denmark)

    Tanev, Stoyan; Sun, Wenbo

    2012-01-01

    This chapter reviews the fundamental methods and some of the applications of the three-dimensional (3D) finite-difference time-domain (FDTD) technique for the modeling of light scattering by arbitrarily shaped dielectric particles and surfaces. The emphasis is on the details of the FDTD algorithms...

  12. Staircase-free finite-difference time-domain formulation for general materials in complex geometries

    DEFF Research Database (Denmark)

    Dridi, Kim; Hesthaven, J.S.; Ditkowski, A.

    2001-01-01

    A stable Cartesian grid staircase-free finite-difference time-domain formulation for arbitrary material distributions in general geometries is introduced. It is shown that the method exhibits higher accuracy than the classical Yee scheme for complex geometries since the computational representation...

  13. A normalized difference vegetation index (NDVI) time-series of idle agriculture lands: A preliminary study

    NARCIS (Netherlands)

    Vaiphasa, C.; Piamduaytham, S.; Vaiphasa, T.; Skidmore, A.K.

    2011-01-01

    In this paper, the NDVI time-series collected from the study area between year 2003 and 2005 of all land cover types are plotted and compared. The study area is the agricultural zones in Banphai District, Khonkean, Thailand. The LANDSAT satellite images of different dates were first transformed into

  14. Short-term solar irradiance and irradiation forecasts via different time series techniques: A preliminary study

    CERN Document Server

    Join, Cédric; Fliess, Michel; Muselli, Marc; Nivet, Marie Laure; Paoli, Christophe; Chaxel, Frédéric

    2014-01-01

    This communication is devoted to solar irradiance and irradiation short-term forecasts, which are useful for electricity production. Several different time series approaches are employed. Our results and the corresponding numerical simulations show that techniques which do not need a large amount of historical data behave better than those which need them, especially when those data are quite noisy.

  15. Acoustic Analyses and Intelligibility Assessments of Timing Patterns among Chinese English Learners with Different Dialect Backgrounds

    Science.gov (United States)

    Chen, Hsueh Chu

    2015-01-01

    This paper includes two interrelated studies. The first production study investigates the timing patterns of English as spoken by Chinese learners with different dialect backgrounds. The second comprehension study explores native and non-native speakers' assessments of the intelligibility of Chinese-accented English, and examines the effects of…

  16. A comparison of different ways to approximate time-to-line crossing (TLC) during car driving

    NARCIS (Netherlands)

    van Winsum, W; Brookhuis, KA; de Waard, D

    2000-01-01

    Three experiments are presented: in which the accuracy of different methods to approximate time-to-line crossing is assessed. In the first experiment TLC was computed, using a trigonometric method, during normal driving while the vehicle stayed in lane. The minima of TLC were compared with two appro

  17. The finite-difference time-domain method for electromagnetics with Matlab simulations

    CERN Document Server

    Elsherbeni, Atef Z

    2016-01-01

    This book introduces the powerful Finite-Difference Time-Domain method to students and interested researchers and readers. An effective introduction is accomplished using a step-by-step process that builds competence and confidence in developing complete working codes for the design and analysis of various antennas and microwave devices.

  18. Television Time among Brazilian Adolescents: Correlated Factors are Different between Boys and Girls

    Directory of Open Access Journals (Sweden)

    Diego Augusto Santos Silva

    2014-01-01

    Full Text Available Objective. The aim of this study was to identify the prevalence of excess television time and verify correlated factors in adolescent males and females. Methods. This cross-sectional study included 2,105 adolescents aged from 13 to 18 years from the city of Aracaju, Northeastern Brazil. Television time was self-reported, corresponding to the time spent watching television in a typical week. Several correlates were examined including age, skin color, socioeconomic status, parent education, physical activity level, consumption of fruits and vegetables, smoking status, alcohol use, and sports team participation. Results. The prevalence excess television time (≥2 hours/day in girls and boys was 70.9% and 66.2%, respectively. Girls with low socioeconomic status or inadequate consumption of fruits and vegetables were more likely to have excess television time. Among boys, those >16 years of age or with black skin color were more likely to have excess television time. Conclusions. Excess television time was observed in more than two-thirds of adolescents, being more evident in girls. Correlated factors differed according to sex. Efforts to reduce television time among Brazilian adolescents, and replace with more active pursuits, may yield desirable public health benefits.

  19. No difference found in time to publication by statistical significance of trial results: a methodological review

    Science.gov (United States)

    Jefferson, L; Cooper, E; Hewitt, C; Torgerson, T; Cook, L; Tharmanathan, P; Cockayne, S; Torgerson, D

    2016-01-01

    Objective Time-lag from study completion to publication is a potential source of publication bias in randomised controlled trials. This study sought to update the evidence base by identifying the effect of the statistical significance of research findings on time to publication of trial results. Design Literature searches were carried out in four general medical journals from June 2013 to June 2014 inclusive (BMJ, JAMA, the Lancet and the New England Journal of Medicine). Setting Methodological review of four general medical journals. Participants Original research articles presenting the primary analyses from phase 2, 3 and 4 parallel-group randomised controlled trials were included. Main outcome measures Time from trial completion to publication. Results The median time from trial completion to publication was 431 days (n = 208, interquartile range 278–618). A multivariable adjusted Cox model found no statistically significant difference in time to publication for trials reporting positive or negative results (hazard ratio: 0.86, 95% CI 0.64 to 1.16, p = 0.32). Conclusion In contrast to previous studies, this review did not demonstrate the presence of time-lag bias in time to publication. This may be a result of these articles being published in four high-impact general medical journals that may be more inclined to publish rapidly, whatever the findings. Further research is needed to explore the presence of time-lag bias in lower quality studies and lower impact journals. PMID:27757242

  20. Geometric and material modeling environment for the finite-difference time-domain method

    Science.gov (United States)

    Lee, Yong-Gu; Muhammad, Waleed

    2012-02-01

    The simulation of electromagnetic problems using the Finite-Difference Time-Domain method starts with the geometric design of the devices and their surroundings with appropriate materials and boundary conditions. This design stage is one of the most time consuming part in the Finite-Difference Time-Domain (FDTD) simulation of photonics devices. Many FDTD solvers have their own way of providing the design environment which can be burdensome for a new user to learn. In this work, geometric and material modeling features are developed on the freely available Google SketchUp, allowing users who are fond of its environment to easily model photonics simulations. The design and implementation of the modeling environment are discussed.

  1. Underwater topography detection of Shuangzi Reefs with SAR images acquired in different time

    Institute of Scientific and Technical Information of China (English)

    YANG Jungang; ZHANG Jie; MENG Junmin

    2007-01-01

    Imaging mechanism of underwater topography by SAR and a underwater topography SAR detection model built on the theory of underwater topography detection with SAR image presented by Yuan Yeli are used to detect the underwater topography of Shuangzi Reefs in the Nansha Islands with three scenes of SAR images acquired in different time. Detection results of three SAR images are compared with the chart topography and the detection errors are analyzed. Underwater topography detection experiments of Shuangzi Reefs show that the detection model is practicable. The detection results indicate that SAR images acquired in different time also can be used to detect the underwater topography, and the detection results are affected by the ocean conditions in the SAR acquiring time.

  2. Impact of different discharge patterns on bed occupancy rate and bed waiting time: a simulation approach.

    Science.gov (United States)

    Zhu, Zhecheng

    2011-01-01

    Beds are one of the most important resources in a healthcare system. How to manage beds efficiently is an important indicator of the efficiency of the healthcare system. Bed management is challenging to many healthcare service providers in many aspects. In recent years, population growth and aging society impose extra pressure on bed requirement. There are usually two key performance indicators of a bed management system: bed occupancy rate and bed waiting time. In this paper, different discharge patterns and their impacts on the bed occupancy rate and bed waiting time are studied. A discrete event simulation model is constructed to evaluate the existing discharge pattern in a Singapore regional hospital using actual hospital admission and discharge transaction data. Then different discharge patterns are tested in the same context. Simulation results show that a proper discharge pattern significantly smoothes the fluctuation of bed occupancy rate and reduce the bed waiting time.

  3. An eye-tracking paradigm for analyzing the processing time of sentences with different linguistic complexities.

    Directory of Open Access Journals (Sweden)

    Dorothea Wendt

    Full Text Available An eye-tracking paradigm was developed for use in audiology in order to enable online analysis of the speech comprehension process. This paradigm should be useful in assessing impediments in speech processing. In this paradigm, two scenes, a target picture and a competitor picture, were presented simultaneously with an aurally presented sentence that corresponded to the target picture. At the same time, eye fixations were recorded using an eye-tracking device. The effect of linguistic complexity on language processing time was assessed from eye fixation information by systematically varying linguistic complexity. This was achieved with a sentence corpus containing seven German sentence structures. A novel data analysis method computed the average tendency to fixate the target picture as a function of time during sentence processing. This allowed identification of the point in time at which the participant understood the sentence, referred to as the decision moment. Systematic differences in processing time were observed as a function of linguistic complexity. These differences in processing time may be used to assess the efficiency of cognitive processes involved in resolving linguistic complexity. Thus, the proposed method enables a temporal analysis of the speech comprehension process and has potential applications in speech audiology and psychoacoustics.

  4. Reconciling extreme branch length differences: decoupling time and rate through the evolutionary history of filmy ferns.

    Science.gov (United States)

    Schuettpelz, Eric; Pryer, Kathleen M

    2006-06-01

    The rate of molecular evolution is not constant across the Tree of Life. Characterizing rate discrepancies and evaluating the relative roles of time and rate along branches through the past are both critical to a full understanding of evolutionary history. In this study, we explore the interactions of time and rate in filmy ferns (Hymenophyllaceae), a lineage with extreme branch length differences between the two major clades. We test for the presence of significant rate discrepancies within and between these clades, and we separate time and rate across the filmy fern phylogeny to simultaneously yield an evolutionary time scale of filmy fern diversification and reconstructions of ancestral rates of molecular evolution. Our results indicate that the branch length disparity observed between the major lineages of filmy ferns is indeed due to a significant difference in molecular evolutionary rate. The estimation of divergence times reveals that the timing of crown group diversification was not concurrent for the two lineages, and the reconstruction of ancestral rates of molecular evolution points to a substantial rate deceleration in one of the clades. Further analysis suggests that this may be due to a genome-wide deceleration in the rate of nucleotide substitution.

  5. Distinction between Clock and Time, and a Suggested Experiment with Different Types of Clocks in GPS

    Science.gov (United States)

    Smarandache, Florentin

    2013-03-01

    The clock is an instrument for measuring the time, instrument that may not run perfectly (accurately) under certain conditions (like, say, in strong electromagnetic field, in strong gravitational field, in extremely high or low temperature, pressure, etc.), but this does not mean that time itself runs slower or faster as Einstein's Theory of Relativity asserts. We are referring to an absolute time, i.e. time measured not with respect to ether or non-ether, but with respect to an absolute mathematical reference frame. Several types of clocks could run at a more slowly rate in a moving frame of reference than other types of clocks; it depends on the construction material and functioning principle of each type of clock. Relativists say that ``gravity slows time''. This is incorrect, since actually gravity slows today's types of clocks. And one type of clock is slowed more or less than another type of clock. Not only gravity but other (electric, magnetic, etc.) fields or various medium composition elements or structures may slow or accelerate clocks that are in that medium. The clocks used today in the satellites for the GPS necessitate a correction with respect to the Earth clocks. But in the future, when new types of clocks will be built based on different construction material and functioning principle, the correction of the GPS clocks would be different. In order to make the distinction between ``clock'' and ``time'', we suggest a Experiment # 1 with different types of clocks for the GPS clocks, in order to prove that the resulted dilation and contraction factors are different from those obtained with today's cesium atomic clock.

  6. Explicit finite-difference time domain for nonlinear analysis of waveguide modes

    Science.gov (United States)

    Barakat, N. M.; Shabat, M. M.; El-Azab, S.; Jaeger, Dieter

    2003-07-01

    The Finite Difference Time Domain Technique is at present the most widely used tool employed in the study of light propagation in various photonic waveguide structure. In this paper we derived an explicit finite-difference time-domain (FDTD) method for solving the wave equation in a four optical waveguiding rectangular structure. We derive the stability condition to achieve the stability in nonlinear media region, we also check that the wave equation used is consistence and convergent with the approximate finite difference equation. Our method is tested against some previous problems and we find a high degree of accuracy, moreover it is easy for programming. Numerical results are illustrated for a rectangular waveguide with four layers, where one of these layers is a nonlinear medium.

  7. Dependecy of the reaction time from the overlap of signal lights with different colors

    Science.gov (United States)

    Klinger, Karsten D.

    2005-02-01

    The rearward signal aspect consists of lights with different colors. With standard technics these signal lights are located at different places. With new technics it is possible to build signal lights with different colors together in one place. The signals overlap. In experiments at the University of Karlsruhe we studied the dependency between reaction time and overlap of signal lights. We can see, that the total overlap from a yellow turn signal and a red brake signal will increase the reaction time. The increase depends of the ratio between the luminance of the turn indicator signal and the luminance of the brake signal. With a ratio from one to one (best case with minimal increase) we found an increase of 300 milli seconds.

  8. Finite Difference Solution of Response Time Delay of Magneto-rhelological Damper

    Institute of Scientific and Technical Information of China (English)

    ZOU Mingsong; HOU Baolin

    2009-01-01

    Magneto-rhelological(MR) dampers are devices that employ rheological fluids to modify their mechanical properties. Their mechanical simplicity, high dynamic range, lower power requirements, large force capacity, robustness and safe manner of operation in cases of failure have made them attractive devices for semi-active real-time control in civil, aerospace and automotive applications. Time response characteristic is one of the most important technical performances of MR dampers, and response time directly affects the control frequency, application range and the actual effect of MR dampers. In this study, one kind of finite difference solution for predicting the response time of magneto-rheological dampers from "off-state" to "on-state" is put forward. A laminar flow model is used to describe the flow in the MR valve, and a bi-viscous fluid flow model is utilized to describe the relationship of shear stress and shear rate of MR fluid. An explicit difference format is used to discretize the Novior-Stoks equation, and stability condition of this algorithm is built by Von-Neumann stability criterion. The pressure gradient along the flow duct is solved by a dichotomy algorithm with iteration, and the changing curve of the damping force versus time of MR damper is obtained as well. According to the abovementioned numerical algorithm, the damping forces versus time curves from "off-state" to "on-state" of a cylindrical piston type MR damper are computed. Moreover, the MR damper is installed in a material test system(MTS), the magnetic field in the wire circles of the MR damper is "triggered" when the MR damper is imposed to do a constant speed motion, and the damping force curves are recorded. The comparison between numerical results and experimental results indicates that this finite difference algorithm can be used to estimate the response time delay of MR dampers.

  9. Comparison of Taxi Time Prediction Performance Using Different Taxi Speed Decision Trees

    Science.gov (United States)

    Lee, Hanbong

    2017-01-01

    In the STBO modeler and tactical surface scheduler for ATD-2 project, taxi speed decision trees are used to calculate the unimpeded taxi times of flights taxiing on the airport surface. The initial taxi speed values in these decision trees did not show good prediction accuracy of taxi times. Using the more recent, reliable surveillance data, new taxi speed values in ramp area and movement area were computed. Before integrating these values into the STBO system, we performed test runs using live data from Charlotte airport, with different taxi speed settings: 1) initial taxi speed values and 2) new ones. Taxi time prediction performance was evaluated by comparing various metrics. The results show that the new taxi speed decision trees can calculate the unimpeded taxi-out times more accurately.

  10. Differences in leisure-time activities according to level of physical activity in adolescents.

    Science.gov (United States)

    Mota, Jorge; Santos, Maria Paula; Ribeiro, Jose Carlos

    2008-03-01

    The main goals of this study were: (1) to examine the relationship between physical activity (PA) involvement and other leisure activities in a sample of Portuguese youth and (2) to analyze gender differences in PA and leisure-time activity structure. The sample comprised 1123 adolescents that were classified according to PA levels as active (n = 589) and nonactive (n = 534). A questionnaire assessing leisure-time activities was used. Girls were significantly more engaged in social leisure, dutiful, and individual artistic activities during leisure time, whereas boys were more involved in sports and computer and TV viewing activities. Significant associations between PA and social leisure were found in girls (r = .18, P artistic activities. This study has certain implications for health-related PA promotion efforts. Our data give additional reinforcement to the importance of organized and nonorganized sports/PA during leisure time for overall levels of PA in adolescents.

  11. The Timing of the Circadian Clock and Sleep Differ between Napping and Non-Napping Toddlers.

    Directory of Open Access Journals (Sweden)

    Lameese D Akacem

    Full Text Available The timing of the internal circadian clock shows large inter-individual variability across the lifespan. Although the sleep-wakefulness pattern of most toddlers includes an afternoon nap, the association between napping and circadian phase in early childhood remains unexplored. This study examined differences in circadian phase and sleep between napping and non-napping toddlers. Data were collected on 20 toddlers (34.2±2.0 months; 12 females; 15 nappers. Children followed their habitual napping and non-napping sleep schedules (monitored with actigraphy for 5 days before an in-home salivary dim light melatonin onset (DLMO assessment. On average, napping children fell asleep during their nap opportunities on 3.6±1.2 of the 5 days before the DLMO assessment. For these napping children, melatonin onset time was 38 min later (p = 0.044; d = 0.93, actigraphically-estimated bedtime was 43 min later (p = 0.014; d = 1.24, sleep onset time was 59 min later (p = 0.006; d = 1.46, and sleep onset latency was 16 min longer (p = 0.030; d = 1.03 than those not napping. Midsleep and wake time did not differ by napping status. No difference was observed in the bedtime, sleep onset, or midsleep phase relationships with DLMO; however, the wake time phase difference was 47 min smaller for napping toddlers (p = 0.029; d = 1.23. On average, nappers had 69 min shorter nighttime sleep durations (p = 0.006; d = 1.47 and spent 49 min less time in bed (p = 0.019; d = 1.16 than non-nappers. Number of days napping was correlated with melatonin onset time (r = 0.49; p = 0.014. Our findings indicate that napping influences individual variability in melatonin onset time in early childhood. The delayed bedtimes of napping toddlers likely permits light exposure later in the evening, thereby delaying the timing of the clock and sleep. Whether the early developmental trajectory of circadian phase involves an advance associated with the decline in napping is a question

  12. The effect of different adhesives and setting times on bond strength between Biodentine and composite.

    Science.gov (United States)

    Çolak, Hakan; Tokay, Uğur; Uzgur, Recep; Uzgur, Zeynep; Ercan, Ertuğrul; Hamidi, Mehmet M

    2016-05-18

    The aim of this study was to evaluate the effects of 3 different adhesives with different functional monomers, on the shear bond strength (SBS) of Biodentine®. Acrylic blocks (n = 90) were prepared and a 2-mm height x 4-mm diameter hole was opened in each block. Every hole was completely restored with Biodentine®. Before preparation of composite restorations over the Biodentine® (2-mm height x 2-mm diameter), 3 different adhesives (Etch-37 (37%) w/BAC by Bisco & Prime Bond N&T, Clearfil S3 Bond and Adper Prompt L-Pop) were applied. SBS was evaluated using a universal testing machine, and failure mode for each sample was recorded. The results were statistically analyzed using 2-way ANOVA and post hoc Tukey test. When the megapascal values of all groups were compared, although there was no statistically significant difference in the different setting times (p>0.05), statistically significant differences were observed among all adhesive groups (p<0.05). Moreover, the highest SBS values were observed in the Clearfil S3 Bond group. Clinical performance of Biodentine® may be affected by adhesive procedures and its setting time.

  13. Characterization of sputtered ZnO films under different sputter-etching time of substrate

    Institute of Scientific and Technical Information of China (English)

    LI Cui-ping; YANG Bao-he; QIAN Li-rong; XU Sheng; DAI Wei; LI Ming-ji; LI Xiao-wei; GAO Cheng-yao

    2011-01-01

    Polycrystalline ZnO films are prepared using radio frequency magnetron sputtering on glass substrates which are sputteretched for different time.Both the size of ZnO grains and the root-mean-square (RMS) roughness decrease,as the sputteretching time of the substrate increases.More Zn atoms are bound to O atoms in the films,and the defect concentration is decreased with increasing sputter-etching time of substrate.Meanwhile,the crystallinity and c-axis orientation are improved at longer sputter-etching time of the substrate.The Raman peaks at 99 cm-1,438 cm-1 and 589 cm-1 are identified as E2(low),E2(high) and E1(LO) modes,respectively,and the position of E1(LO) peak blue shifts at longer sputter-etching time.The transmittances of the films,which are deposited on the substrate and etched for 10 min and 20 min,are higher in the visible region than that of the films deposited under longer sputter-etching time of 30 min.The bandgap increases from 3.23 eV to 3.27 eV with the increase of the sputter-etching time of substrate.

  14. Snacking now or later? Individual differences in following intentions or habits explained by time perspective.

    Science.gov (United States)

    Onwezen, M C; Van 't Riet, J; Dagevos, H; Sijtsema, S J; Snoek, H M

    2016-12-01

    Even when individuals are aware of long-term health effects of their diet, and form healthy intentions, they often engage in relatively unhealthy snacking habits. Some individuals fall back on unhealthy habits more easily than others. We aim to explore whether time perspective can explain why some individuals are more prone to rely on habits and others on intentions. Study 1 (N = 1503) provides a first exploration of the role of time perspective by exploring individual differences in perception of long-term and short-term consequences. In accordance with our hypotheses, Study 1 shows that habits are associated with short-term consequences and intentions with long-term consequences. Study 2 (N = 1497) shows that the effects of habits on snacking behaviour are strengthened by a present time perspective, whereas the effects of intentions on snacking behaviour are strengthened by a future time perspective. These findings imply that there is a fundamental difference in the guiding function of intentions and habits which might explain individual differences in following intentions versus habits. Individuals with a long-term perspective are more inclined to follow intentions and individuals with a short-term perspective are more inclined to follow habits.

  15. Stochastic phase resetting of two coupled phase oscillators stimulated at different times

    Science.gov (United States)

    Tass, Peter A.

    2003-05-01

    A model of two coupled phase oscillators is presented, where the oscillators are subject to random forces and are stimulated at different times. Transient phase dynamics, synchronization, and desynchronization, which are stimulus locked (i.e., tightly time locked to a repetitively administered stimulus), are investigated. Complex coordinated responses, in terms of a noise-induced switching across trials between qualitatively different responses, may occur when the two oscillators are reset close to an unstable fixed point of their relative phases. This can be achieved with an appropriately chosen delay between the two stimuli. The switching of the responses shows up as a coordinated cross-trial (CT) response clustering of the oscillators, where the two oscillators produce two different pairs of responses. By varying noise amplitude and coupling strength we observe a stochastic resonance and a coupling-mediated resonance of the CT response clustering, respectively. The presented data analysis method makes it possible to detect such processes in numerical and experimental signals. Its time resolution is enormous, since it is only restricted by the time resolution of the preprocessing necessary for extracting the phases from experimental data. In contrast, standard data analysis tools applied across trials relative to stimulus onset, such as CT averaging (where an ensemble of poststimulus responses is simply averaged), CT standard deviation, and CT cross correlation, fail in detecting complex coordinated responses and lead to severe misinterpretations and artifacts. The consequences for the analysis of evoked responses in medicine and neuroscience are significant and are discussed in detail.

  16. Motor and perceptual sequence learning: different time course of parallel processes.

    Science.gov (United States)

    Dirnberger, Georg; Novak-Knollmueller, Judith

    2013-07-10

    The aim was to determine the extent and time course of motor and perceptual learning in a procedural learning task, and the relation of these two processes. Because environmental constraints modulate the relative impact of different learning mechanisms, we chose a simple learning task similar to real-life exercise. Thirty-four healthy individuals performed a visuomotor serial reaction time task. Learning blocks with high stimulus-response compatibility were practiced repeatedly; in between these, participants performed test blocks with the same or a different (mirror-inverted, or new) stimulus sequence and/or with the same or a different (mirror-inverted) stimulus-response allocation. This design allowed us to measure the progress of motor learning and perceptual learning independently. Results showed that in the learning blocks, a steady reduction of the reaction times indicated that - as expected - participants improved their skills continuously. Analysis of the test blocks indicated that both motor learning and perceptual learning were significant. The two mechanisms were correlated (r=0.62, Pperceptual learning was more stable but slower. In conclusion, in a simple visuomotor learning task, participants can learn the motor sequence and the stimulus sequence in parallel. The positive correlation of motor and perceptual learning suggests that the two mechanisms act in synergy and are not alternative opposing strategies. The impact of these two learning mechanisms changes over time: motor learning sets in later and becomes relevant only in the course of training.

  17. Streamflow response of a small forested catchment on different time scales

    Directory of Open Access Journals (Sweden)

    A. Zabaleta

    2012-08-01

    Full Text Available The hydrological response of a catchment to rainfall on different time scales is result of a complex system involving a range of physical processes which may operate simultaneously and have different spatial and temporal influences. This paper presents the analysis of streamflow response of a small humid-temperate catchment (Aixola, 4.8 km2 in the Basque Country on different time scales and discusses the role of the controlling factors. Firstly, daily time series analysis was used to establish a hypothesis on the general functioning of the catchment through the relationship between precipitation and discharge on an annual and multi-annual scale (2003–2008. Second, rainfall-runoff relationships and relationships among several hydrological variables, including catchment antecedent conditions, were explored at the event scale (222 events to check and improve the hypothesis. Finally, the evolution of electrical conductivity (EC during some of the monitored storm events (28 events was examined to identify the time-origin of waters. Quick response of the catchment to almost all the rainfall events as well as a considerable regulation capacity was deduced from the correlation and spectral analyses. These results agree with runoff event scale data analysis; however the event analysis revealed the non-linearity of the system, as antecedent conditions play a significant role in this catchment. Further, analysis at the event scale made possible to clarify factors controlling (precipitation, precipitation intensity and initial discharge the different aspects of the runoff response (runoff coefficient and discharge increase for this catchment. Finally, the evolution of EC of the waters enabled the time origin (event or pre-event waters of the quickflow to be established; specifically, the conductivity showed that pre-event waters usually represent a high percentage of the total discharge during runoff peaks. The importance of soil waters in the

  18. Residence times and alluvial architecture of a sediment superslug in response to different flow regimes

    Science.gov (United States)

    Moody, John A.

    2017-10-01

    A superslug was deposited in a basin in the Colorado Front Range Mountains as a consequence of an extreme flood following a wildfire disturbance in 1996. The subsequent evolution of this superslug was measured by repeat topographic surveys (31 surveys from 1996 through 2014) of 18 cross sections approximately uniformly spaced over 1500 m immediately above the basin outlet. These surveys allowed the identification within the superslug of chronostratigraphic units deposited and eroded by different geomorphic processes in response to different flow regimes. Over the time period of the study, the superslug went through aggradation, incision, and stabilization phases that were controlled by a shift in geomorphic processes from generally short-duration, episodic, large-magnitude floods that deposited new chronostratigraphic units to long-duration processes that eroded units. These phases were not contemporaneous at each channel cross section, which resulted in a complex response that preserved different chronostratigraphic units at each channel cross section having, in general, two dominant types of alluvial architecture-laminar and fragmented. Age and transit-time distributions for these two alluvial architectures evolved with time since the extreme flood. Because of the complex shape of the distributions they were best modeled by two-parameter Weibull functions. The Weibull scale parameter approximated the median age of the distributions, and the Weibull shape parameter generally had a linear relation that increased with time since the extreme flood. Additional results indicated that deposition of new chronostratigraphic units can be represented by a power-law frequency distribution, and that the erosion of units decreases with depth of burial to a limiting depth. These relations can be used to model other situations with different flow regimes where vertical aggradation and incision are dominant processes, to predict the residence time of possible contaminated

  19. Residence times and alluvial architecture of a sediment superslug in response to different flow regimes

    Science.gov (United States)

    Moody, John A.

    2017-01-01

    A superslug was deposited in a basin in the Colorado Front Range Mountains as a consequence of an extreme flood following a wildfire disturbance in 1996. The subsequent evolution of this superslug was measured by repeat topographic surveys (31 surveys from 1996 through 2014) of 18 cross sections approximately uniformly spaced over 1500 m immediately above the basin outlet. These surveys allowed the identification within the superslug of chronostratigraphic units deposited and eroded by different geomorphic processes in response to different flow regimes.Over the time period of the study, the superslug went through aggradation, incision, and stabilization phases that were controlled by a shift in geomorphic processes from generally short-duration, episodic, large-magnitude floods that deposited new chronostratigraphic units to long-duration processes that eroded units. These phases were not contemporaneous at each channel cross section, which resulted in a complex response that preserved different chronostratigraphic units at each channel cross section having, in general, two dominant types of alluvial architecture—laminar and fragmented. Age and transit-time distributions for these two alluvial architectures evolved with time since the extreme flood. Because of the complex shape of the distributions they were best modeled by two-parameter Weibull functions. The Weibull scale parameter approximated the median age of the distributions, and the Weibull shape parameter generally had a linear relation that increased with time since the extreme flood. Additional results indicated that deposition of new chronostratigraphic units can be represented by a power-law frequency distribution, and that the erosion of units decreases with depth of burial to a limiting depth. These relations can be used to model other situations with different flow regimes where vertical aggradation and incision are dominant processes, to predict the residence time of possible contaminated

  20. Music, clicks, and their imaginations favor differently the event-based timing component for rhythmic movements.

    Science.gov (United States)

    Bravi, Riccardo; Quarta, Eros; Del Tongo, Claudia; Carbonaro, Nicola; Tognetti, Alessandro; Minciacchi, Diego

    2015-06-01

    The involvement or noninvolvement of a clock-like neural process, an effector-independent representation of the time intervals to produce, is described as the essential difference between event-based and emergent timing. In a previous work (Bravi et al. in Exp Brain Res 232:1663-1675, 2014a. doi: 10.1007/s00221-014-3845-9 ), we studied repetitive isochronous wrist's flexion-extensions (IWFEs), performed while minimizing visual and tactile information, to clarify whether non-temporal and temporal characteristics of paced auditory stimuli affect the precision and accuracy of the rhythmic motor performance. Here, with the inclusion of new recordings, we expand the examination of the dataset described in our previous study to investigate whether simple and complex paced auditory stimuli (clicks and music) and their imaginations influence in a different way the timing mechanisms for repetitive IWFEs. Sets of IWFEs were analyzed by the windowed (lag one) autocorrelation-wγ(1), a statistical method recently introduced for the distinction between event-based and emergent timing. Our findings provide evidence that paced auditory information and its imagination favor the engagement of a clock-like neural process, and specifically that music, unlike clicks, lacks the power to elicit event-based timing, not counteracting the natural shift of wγ(1) toward positive values as frequency of movements increase.

  1. Striatal lesions produce distinctive impairments in reaction time performance in two different operant chambers.

    Science.gov (United States)

    Brasted, P J; Döbrössy, M D; Robbins, T W; Dunnett, S B

    1998-08-01

    The dorsal striatum plays a crucial role in mediating voluntary movement. Excitotoxic striatal lesions in rats have previously been shown to impair the initiation but not the execution of movement in a choice reaction time task in an automated lateralised nose-poke apparatus (the "nine-hole box"). Conversely, when a conceptually similar reaction time task has been applied in a conventional operant chamber (or "Skinner box"), striatal lesions have been seen to impair the execution rather than the initiation of the lateralised movement. The present study was undertaken to compare directly these two results by training the same group of rats to perform a choice reaction time task in the two chambers and then comparing the effects of a unilateral excitotoxic striatal lesion in both chambers in parallel. Particular attention was paid to adopting similar parameters and contingencies in the control of the task in the two test chambers. After striatal lesions, the rats showed predominantly contralateral impairments in both tasks. However, they showed a deficit in reaction time in the nine-hole box but an apparent deficit in response execution in the Skinner box. This finding confirms the previous studies and indicates that differences in outcome are not simply attributable to procedural differences in the lesions, training conditions or tasks parameters. Rather, the pattern of reaction time deficit after striatal lesions depends critically on the apparatus used and the precise response requirements for each task.

  2. Nitrogen fertilization in irrigated common bean at different times, with and without dose division

    Directory of Open Access Journals (Sweden)

    Danilo Pereira Ramos

    2014-03-01

    Full Text Available This article aims to evaluate the effect of nitrogen fertilization at different times on the agronomic characteristics of common bean cultivars, within the intercrop period. An experiment was installed in the town of Gurupi, Tocantins, Brazil, with randomized blocks, under a 3 x 5 factorial scheme, consisting of 3 cultivars and 5 nitrogen application times, with 4 repetitions. We evaluated the cultivars IAC Alvorada, IPR Juriti, and BRS Requinte. Regarding nitrogen fertilization, we evaluated 5 times, the first corresponding to control (E1 = N zero and the others applying 100 kg.ha-1 of nitrogen, using urea as their source, as follows: E2 = 100% of N applied at sowing; E3 = 100% of N applied 25 days after emergence (DAE; E4 = 50% of N applied 20 DAE and 50% 30 DAE; E5 = 33% of N applied 15 DAE, 33% 25 DAE, and 33% 35 DAE. There was genetic variability among cultivars with regard to response, as well as differences between nitrogen fertilization times. The cultivars IAC Alvorada and IPR Juriti obtained higher grain yields. The nitrogen application time divided into 15, 25 and 35 DAE enabled a higher grain yield for the cultivars IAC Alvorada and IPR Juriti.

  3. A detection model of underwater topography with a series of SAR images acquired at different time

    Institute of Scientific and Technical Information of China (English)

    YANG Jungang; ZHANG Jie; MENG Junmin

    2010-01-01

    underwater topography is one of oceanic features detected by Synthetic Aperture Radar. Under-water topography SAR imaging mechanism shows that tidal current is the important factor for underwater topography SAR imaging. Thus under the same wind field condition, SAR images for the same area acquired at different time include different information of the underwater topogra-phy. To utilize synchronously SAR images acquired at different time for the underwater topography SAR detection and improve the precision of detection, based on the detection model of underwater topography with single SAR image and the periodicity of tidal current, a detection model of under- water topography with a series of SAR images acquired at different time is developed by combing with tide and tidal current numerical simulation. To testify the feasibility of the presented model, Taiwan Shoal located at the south outlet of Taiwan Strait is selected as study area and three SAR images are used in the underwater topography detection. The detection results are compared with the field observation data of water depth carried out by R/V Dongfanghong 2, and the errors of the detection are compared with those of the single SAR image. All comparisons show that the detec- tion model presented in the paper improves the precision of underwater topography SAR detection, and the presented model is feasible.

  4. Individual differences affecting caffeine intake. Analysis of consumption behaviours for different times of day and caffeine sources.

    Science.gov (United States)

    Penolazzi, Barbara; Natale, Vincenzo; Leone, Luigi; Russo, Paolo Maria

    2012-06-01

    The main purpose of the present study was to investigate the individual variables contributing to determine the high variability in the consumption behaviours of caffeine, a psychoactive substance which is still poorly investigated in comparison with other drugs. The effects of a large set of specific personality traits (i.e., Impulsivity, Sensation Seeking, Anxiety, Reward Sensitivity and Circadian Preference) were compared along with some relevant socio-demographic variables (i.e., gender and age) and cigarette smoking behaviour. Analyses revealed that daily caffeine intake was significantly higher for males, older people, participants smoking more cigarettes and showing higher scores on Impulsivity, Sensation Seeking and a facet of Reward Sensitivity. However, more detailed analyses showed that different patterns of individual variables predicted caffeine consumption when the times of day and the caffeine sources were considered. The present results suggest that such detailed analyses are required to detect the critical predictive variables that could be obscured when only total caffeine intake during the entire day is considered. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Comparing trends in hydrometeorological average and extreme data sets around the world at different time scales

    Directory of Open Access Journals (Sweden)

    Thomas Rosmann

    2016-03-01

    New hydrological insights for the region: Results indicate that trends can be found for all variables and on all latitudes, with an increase of global temperature in the analysed time period. Fewer trends were observed in extreme value data. Trends in discharge data were predominantly negative, and precipitation trends were not very common. In some cases, an opposing pattern was observed in the northern and southern hemisphere. The highest number of trends was found at the annual and least on the daily resolution, nevertheless, trend patterns for discharges remained similar at different time scales. Some of the factors that might influence these results are discussed.

  6. SENSORY ANALYSIS OF CUCUMBER VARIETIES AT DIFFERENT HARVEST TIMES II. PICKLING CUCUMBERS

    Directory of Open Access Journals (Sweden)

    Galina PEVICHAROVA

    2010-02-01

    Full Text Available During the period 2001-2002 sensory analysis of Bulgarian pickling cucumber varieties Toni, Iren and Pobeda was carried out. The varieties had identical parent female breeding line G-3. Fresh and canned fruits were evaluated at three harvest times. It was established that sensory properties of canned fruits cannot be entirely prognosticated from panel test data of the fresh ones. For breeding purposes sensory analysis of pickling cucumbers for processing should be performed using sterilized pickling cucumbers but not only fresh ones. More precise information about visual and gustatory properties of new created lines and hybrids will be obtained by performing of sensory analysis at different harvest times.

  7. Effective optical response of silicon to sunlight in the finite-difference time-domain method.

    Science.gov (United States)

    Deinega, Alexei; John, Sajeev

    2012-01-01

    The frequency dependent dielectric permittivity of dispersive materials is commonly modeled as a rational polynomial based on multiple Debye, Drude, or Lorentz terms in the finite-difference time-domain (FDTD) method. We identify a simple effective model in which dielectric polarization depends both on the electric field and its first time derivative. This enables nearly exact FDTD simulation of light propagation and absorption in silicon in the spectral range of 300-1000 nm. Numerical precision of our model is demonstrated for Mie scattering from a silicon sphere and solar absorption in a silicon nanowire photonic crystal.

  8. Analysis of oscillational instabilities in acoustic levitation using the finite-difference time-domain method

    DEFF Research Database (Denmark)

    Santillan, Arturo Orozco

    2011-01-01

    The aim of the work described in this paper has been to investigate the use of the finite-difference time-domain method to describe the interactions between a moving object and a sound field. The main objective was to simulate oscillational instabilities that appear in single-axis acoustic...... levitation devices and to describe their evolution in time to further understand the physical mechanism involved. The study shows that the method gives accurate results for steady state conditions, and that it is a promising tool for simulations with a moving object....

  9. Real-Time Difference Imaging Analysis of MOA Galactic Bulge Observations During 2000

    OpenAIRE

    Bond, I. A.; Abe, F.; Dodd, R. J.; Hearnshaw, J. B.; Honda, M.; Jugaku, J.; Kilmartin, P. M.; Marles, A.; Masuda, K.; Matsubara, Y.; Muraki, Y.(Solar-Terrestrial Environment Laboratory, Nagoya University, Japan); Nakamura, T.; Nankivell, G.; Noda, S.; Noguchi, C.

    2001-01-01

    We describe observations carried out by the MOA group of the Galactic Bulge during 2000 that were designed to detect efficiently gravitational microlensing of faint stars in which the magnification is high and/or of short duration. These events are particularly useful for studies of extra-solar planets and faint stars. Approximately 17 degrees square were monitored at a sampling rate of up to 6 times per night. The images were analysed in real-time using a difference imaging technique. Twenty...

  10. Spectral difference Lanczos method for efficient time propagation in quantum control theory.

    Science.gov (United States)

    Farnum, John D; Mazziotti, David A

    2004-04-01

    Spectral difference methods represent the real-space Hamiltonian of a quantum system as a banded matrix which possesses the accuracy of the discrete variable representation (DVR) and the efficiency of finite differences. When applied to time-dependent quantum mechanics, spectral differences enhance the efficiency of propagation methods for evolving the Schrodinger equation. We develop a spectral difference Lanczos method which is computationally more economical than the sinc-DVR Lanczos method, the split-operator technique, and even the fast-Fourier-Transform Lanczos method. Application of fast propagation is made to quantum control theory where chirped laser pulses are designed to dissociate both diatomic and polyatomic molecules. The specificity of the chirped laser fields is also tested as a possible method for molecular identification and discrimination.

  11. Cost minimization analysis of different growth hormone pen devices based on time-and-motion simulations

    Directory of Open Access Journals (Sweden)

    Kim Jaewhan

    2010-04-01

    Full Text Available Abstract Background Numerous pen devices are available to administer recombinant Human Growth Hormone (rhGH, and both patients and health plans have varying issues to consider when selecting a particular product and device for daily use. Therefore, the present study utilized multi-dimensional product analysis to assess potential time involvement, required weekly administration steps, and utilization costs relative to daily rhGH administration. Methods Study objectives were to conduct 1 Time-and-Motion (TM simulations in a randomized block design that allowed time and steps comparisons related to rhGH preparation, administration and storage, and 2 a Cost Minimization Analysis (CMA relative to opportunity and supply costs. Nurses naïve to rhGH administration and devices were recruited to evaluate four rhGH pen devices (2 in liquid form, 2 requiring reconstitution via TM simulations. Five videotaped and timed trials for each product were evaluated based on: 1 Learning (initial use instructions, 2 Preparation (arrange device for use, 3 Administration (actual simulation manikin injection, and 4 Storage (maintain product viability between doses, in addition to assessment of steps required for weekly use. The CMA applied micro-costing techniques related to opportunity costs for caregivers (categorized as wages, non-drug medical supplies, and drug product costs. Results Norditropin® NordiFlex and Norditropin® NordiPen (NNF and NNP, Novo Nordisk, Inc., Bagsværd, Denmark took less weekly Total Time (p ® Pen (GTP, Pfizer, Inc, New York, New York or HumatroPen® (HTP, Eli Lilly and Company, Indianapolis, Indiana. Time savings were directly related to differences in new package Preparation times (NNF (1.35 minutes, NNP (2.48 minutes GTP (4.11 minutes, HTP (8.64 minutes, p Conclusions Time-and-motion simulation data used to support a micro-cost analysis demonstrated that the pen device with the greater time demand has highest net costs.

  12. The impact of different sampling rates and calculation time intervals on ROTI values

    Directory of Open Access Journals (Sweden)

    Jacobsen Knut Stanley

    2014-01-01

    Full Text Available The ROTI (Rate of TEC index is a commonly used measure of ionospheric irregularities level. The algorithm to calculate ROTI is easily implemented, and is the same from paper to paper. However, the sample rate of the GNSS data used, and the time interval over which a value of ROTI is calculated, varies from paper to paper. When comparing ROTI values from different studies, this must be taken into account. This paper aims to show what these differences are, to increase the awareness of this issue. We have investigated the effect of different parameters for the calculation of ROTI values, using one year of data from 8 receivers at latitudes ranging from 59° N to 79° N. We have found that the ROTI values calculated using different parameter choices are strongly positively correlated. However, the ROTI values are quite different. The effect of a lower sample rate is to lower the ROTI value, due to the loss of high-frequency parts of the ROT spectrum, while the effect of a longer calculation time interval is to remove or reduce short-lived peaks due to the inherent smoothing effect. The ratio of ROTI values based on data of different sampling rate is examined in relation to the ROT power spectrum. Of relevance to statistical studies, we find that the median level of ROTI depends strongly on sample rate, strongly on latitude at auroral latitudes, and weakly on time interval. Thus, a baseline “quiet” or “noisy” level for one location or choice or parameters may not be valid for another location or choice of parameters.

  13. Generalized Projective Synchronization between Two Different Neural Networks with Mixed Time Delays

    Directory of Open Access Journals (Sweden)

    Xuefei Wu

    2012-01-01

    Full Text Available The generalized projective synchronization (GPS between two different neural networks with nonlinear coupling and mixed time delays is considered. Several kinds of nonlinear feedback controllers are designed to achieve GPS between two different such neural networks. Some results for GPS of these neural networks are proved theoretically by using the Lyapunov stability theory and the LaSalle invariance principle. Moreover, by comparison, we determine an optimal nonlinear controller from several ones and provide an adaptive update law for it. Computer simulations are provided to show the effectiveness and feasibility of the proposed methods.

  14. The two chromosomes of Vibrio cholerae are initiated at different time points in the cell cycle

    DEFF Research Database (Denmark)

    Rasmussen, Tue; Jensen, Rasmus Bugge; Skovgaard, Ole

    2007-01-01

    The bacterium Vibrio cholerae, the cause of the diarrhoeal disease cholera, has its genome divided between two chromosomes, a feature uncommon for bacteria. The two chromosomes are of different sizes and different initiator molecules control their replication independently. Using novel methods...... at approximately the same time and the average number of replication origins per cell is higher for chromosome I than for chromosome II. Analysis of cell-cycle parameters shows that chromosome replication and segregation is exceptionally fast in V. cholerae. The divided genome and delayed replication of chromosome...

  15. Experimental study on remodeling strength of granular materials under different loads and lengths of time

    Institute of Scientific and Technical Information of China (English)

    韩流; 周伟; 才庆祥; 舒继森; 靖洪文; 李鑫

    2015-01-01

    Remodeled clay and sand rock specimens were prepared by designing lateral confinement and water drainage experiments based on the stress exerted on granular materials in a waste dump. An in situ test was conducted in an internal waste dump; the physical and mechanical parameters of the remodeled rock mass dumped at different time and depths were measured. Based on statistics, regression analysis was performed with regard to the shearing stress parameters acquired from the two tests. Other factors, such as remodeling pressure (burial depth), remodeling time (amount of time since waste was dumped), and the corresponding functional relationship, were determined. Analysis indicates that the cohesion of the remodeled clay and its remodeling pressure are correlated by a quadratic function but are not correlated with remodeling time length. In situ experimental results indicate that the shear strength of reshaped granular materials in the internal dump is positively correlated with burial depth but poorly correlated with time length. CohesionC and burial depthH follow a quadratic function, specifically for a short time since waste has been dumped. As revealed by both in situ and laboratory experiments, the remodeling strength of granular materials varies in a certain pattern. The consistency of such materials verifies the reliability of the remodeling experimental program.

  16. Damaging Effects of Multi-walled Carbon Nanotubes on Pregnant Mice with Different Pregnancy Times

    Science.gov (United States)

    Qi, Wei; Bi, Juanjuan; Zhang, Xiaoyong; Wang, Jing; Wang, Jianjun; Liu, Peng; Li, Zhan; Wu, Wangsuo

    2014-03-01

    The mechanism by which nanoparticles cross the placental barrier was studied by using isotopic tracers. The abortion rates and other related data were counted and analysed in pregnant mice with different pregnancy times. Results showed that oxidised multi-walled carbon nanotubes (oMWCNTs) crossed the placental barrier and entered the foetus body. The abortion rates in the pregnant mice depended on pregnancy times. The abortion rates in the first-time, second-time and fourth-time pregnant mice were 70%, 40% and 50%, respectively. The maternal body weight gain was inhibited until gestational ages of 13, 10 and 11 d. oMWCNTs decreased the serum progesterone level and increased the serum oestradiol level in a dose- and time-dependent manner. However, this effect decreased with gestational age. The histology and vascular endothelial growth factor/reactive oxygen species content in the placenta showed that oMWCNTs narrowed the blood vessel and decreased the number of blood vessels in the placenta.

  17. Study of the solar wind-magnetosphere coupling on different time scales

    CERN Document Server

    Badruddin,

    2013-01-01

    Solar wind-magnetosphere coupling, its causes and consequences have been studied for the last several decades. However, the assessment of continuously changing behaviour of the sun, plasma and field flows in the interplanetary space and their influence on geomagnetic activity is still a subject of intense research. Search for the best possible coupling function is also important for space weather prediction. We utilize four geomagnetic indices (ap, aa, AE and Dst) as parameters of geomagnetic activity level in the earth's magnetosphere. In addition to these indices, we utilize various solar wind plasma and field parameters for the corresponding periods. We analyse the geomagnetic activity and plasma/field parameters at yearly, half-yearly, 27-day, daily, 3-hourly, and hourly time resolutions. Regression analysis using geomagnetic and solar wind data of different time resolutions, over a continuous long period, and at different phases of solar activity (increasing including maximum/decreasing including minimum...

  18. Exact Finite-Difference Time-Domain Modelling of Broadband Huygens' Metasurfaces with Lorentz Dispersions

    CERN Document Server

    Smy, Tom J

    2016-01-01

    An explicit time-domain finite-difference technique for modelling zero-thickness Huygens' metasurfaces based on Generalized Sheet Transition Conditions (GSTCs), is proposed and demonstrated using full-wave simulations. The Huygens' metasurface is modelled using electric and magnetic surface susceptibilities, which are found to follow a double-Lorentz dispersion profile. To solve zero-thickness Huygens' metasurface problems for general broadband excitations, the double-Lorentz dispersion profile is combined with GSTCs, leading to a set of first-order differential fields equations in time-domain. Identifying the exact equivalence between Huygens' metasurfaces and coupled RLC oscillator circuits, the field equations are then subsequently solved using standard circuit modelling techniques based on a finite-difference formulation. Several examples including generalized refraction are shown to illustrate the temporal evolution of scattered fields from the Huygens' metasurface under plane-wave normal incidence, in b...

  19. Alzheimer’s Disease: Differences of Transdermal versus Oral Treatment on Caregiving Time

    Directory of Open Access Journals (Sweden)

    O. Riedel

    2012-11-01

    Full Text Available Background: Data on indirect effects of dementia treatment on caregiver burden obtained from naturalistic studies are still lacking. We explored differences between patients with oral and transdermal application of acetylcholine esterase inhibitors regarding caregiver’s time burden and psychopathology. Methods: A cross-sectional naturalistic cohort study of 403 patients in outpatient care with three treatment groups (none, oral, and transdermal was conducted. Assessments included a standardized clinical burden questionnaire and a standardized caregiver interview. Results: Any treatment was associated with lower burden in most measures. Transdermal treatment was superior regarding (1 administration time (p Conclusions: Benefits associated with transdermal treatment do not translate into a better ‘generic quality of life’ of the caregiver. The substantially different perceptions of patients’ improvements need to be considered in future studies.

  20. Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth

    Directory of Open Access Journals (Sweden)

    A. Lastras-Martínez

    2014-03-01

    Full Text Available We report on real time-resolved Reflectance-difference (RD spectroscopy of GaAs(001 grown by molecular beam epitaxy, with a time-resolution of 500 ms per spectrum within the 2.3–4.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors.

  1. The Semantic Associative Ability in Preschoolers with Different Language Onset Time.

    Science.gov (United States)

    Di Giacomo, Dina; Ranieri, Jessica; Donatucci, Eliana; Caputi, Nicoletta; Passafiume, Domenico

    2016-01-01

    Aim of the study is to verify the semantic associative abilities in children with different language onset times: early, typical, and delayed talkers. The study was conducted on the sample of 74 preschool children who performed a Perceptual Associative Task, in order to evaluate the ability to link concepts by four associative strategies (function, part/whole, contiguity, and superordinate strategies). The results evidenced that the children with delayed language onset performed significantly better than the children with early language production. No difference was found between typical and delayed language groups. Our results showed that the children with early language onset presented weakness in the flexibility of elaboration of the concepts. The typical and delayed language onset groups overlapped performance in the associative abilities. The time of language onset appeared to be a predictive factor in the use of semantic associative strategies; the early talkers might present a slow pattern of conceptual processing, whereas the typical and late talkers may have protective factors.

  2. Influence of Different Temperature Sensors on Measuring Energy Efficiency and Heating-Up Time of Hobs

    Science.gov (United States)

    Beges, G.; Drnovsek, J.; Ogorevc, J.; Bojkovski, J.

    2015-03-01

    Measuring performance, mainly temperature dependence, for electric cooking ranges, hobs, ovens, and grills for household use is essential for producers as low power consumption of appliances represents a powerful selling point and also in terms of ecodesign requirements. It is also important from a consumer perspective, as these appliances are responsible for the significant share of households' electricity bills. The aim of the paper was to highlight and clearly define possible ambiguities and weaknesses of standardized procedures for measuring hob performance. Differences between measurement/test results of testing laboratories are possible due to lack of detailed information in the standard, and it is difficult to obtain technical accessories required in the standard. An energy consumption comparison of three different hobs is presented (standard iron electrical hob, radiant-glass ceramic, and induction hob). Various temperature sensors (different types of thermocouples and a platinum resistance thermometer) and technical accessories (e.g., different cookware) were used to research differences or influences on final result of hobs' energy efficiency. Results show that temperature measurements with different sensors have an influence on the time difference in critical points for determination of hob energy efficiency.

  3. Decay Time Measurement for Different Energy Depositions of Plastic Scintillator Fabricated by High Temperature Polymerization Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Cheol Ho; Son, Jaebum; Lee, Sangmin; Kim, Tae Hoon; Kim, Yong-Kyun [Hanyang University, Seoul (Korea, Republic of)

    2016-10-15

    Plastic scintillators are based on organic fluorite. They have many advantages such as fast rise and decay time, high optical transmission, ease of manufacturing, low cost, and large available size. For these reasons they are widely used for particle identification. Also, protection of people against a variety of threats (such as nuclear, radiological, and explosive) represents a true challenge along with the continuing development of science and technology. The plastic scintillator is widely used in various devise, which serves for nuclear, photonics, quantum, and high-energy physics. The plastic scintillator is probably the most widely used organic detector, and polystyrene is one of the most widely used materials in the making of the plastic scintillator detector. Thus, a styrene monomer as a solvent was used to fabricate the plastic scintillator by using high temperature polymerization reaction, and then the emission wavelength and the decay times for different energy depositions were measured by using the fabricated plastic scintillator. A plastic scintillator was fabricated to measure decay time for different energy depositions using the high temperature polymerization. Emission wavelength was measured of 426.05 nm to confirm a scintillator property using the spectrophotometer. Four gamma-ray sources (Cs-137, Co-60, Na-22, and Ba-133) were used to evaluate effect for decay time of different energy depositions. The average decay time of the fabricated plastic scintillator was measured to approximately 4.72 ns slightly higher more than commercial plastic scintillator. In future, light output and linearity will be measured to evaluate other property compared with the commercial scintillator.

  4. Impact of different cloud deployments on real-time video applications for mobile video cloud users

    Science.gov (United States)

    Khan, Kashif A.; Wang, Qi; Luo, Chunbo; Wang, Xinheng; Grecos, Christos

    2015-02-01

    The latest trend to access mobile cloud services through wireless network connectivity has amplified globally among both entrepreneurs and home end users. Although existing public cloud service vendors such as Google, Microsoft Azure etc. are providing on-demand cloud services with affordable cost for mobile users, there are still a number of challenges to achieve high-quality mobile cloud based video applications, especially due to the bandwidth-constrained and errorprone mobile network connectivity, which is the communication bottleneck for end-to-end video delivery. In addition, existing accessible clouds networking architectures are different in term of their implementation, services, resources, storage, pricing, support and so on, and these differences have varied impact on the performance of cloud-based real-time video applications. Nevertheless, these challenges and impacts have not been thoroughly investigated in the literature. In our previous work, we have implemented a mobile cloud network model that integrates localized and decentralized cloudlets (mini-clouds) and wireless mesh networks. In this paper, we deploy a real-time framework consisting of various existing Internet cloud networking architectures (Google Cloud, Microsoft Azure and Eucalyptus Cloud) and a cloudlet based on Ubuntu Enterprise Cloud over wireless mesh networking technology for mobile cloud end users. It is noted that the increasing trend to access real-time video streaming over HTTP/HTTPS is gaining popularity among both research and industrial communities to leverage the existing web services and HTTP infrastructure in the Internet. To study the performance under different deployments using different public and private cloud service providers, we employ real-time video streaming over the HTTP/HTTPS standard, and conduct experimental evaluation and in-depth comparative analysis of the impact of different deployments on the quality of service for mobile video cloud users. Empirical

  5. DIFFERENCES IN EXERCISE PERFORMANCE AND LEISURE-TIME PHYSICAL ACTIVITY IN OLDER MEN AND WOMEN

    OpenAIRE

    Andrew W. Gardner; Montgomery, Polly S.

    2008-01-01

    Purposes: (a) To compare exercise performance and leisure-time physical activity (LTPA) between older men and women, (b) to assess the relationship between exercise performance and LTPA, and (c) to determine whether group differences in exercise performance persist after controlling for LTPA.Methods: A total of 105 women and 155 men who were 65 years of age and older participated in this study. Subjects were characterized on exercise performance by a 6-minute walk test, and by a short physi...

  6. Dental enamel roughness with different acid etching times: Atomic force microscopy study

    OpenAIRE

    2012-01-01

    Objective: An important characteristic of human dental enamel not yet studied in detail is its surface roughness in mesoscopic scale. This study evaluated quantitatively and qualitatively the surface topography of acid etched enamel with different etching times. Materials and Methods: Ninety-six human maxillary bicuspids were randomly distributed into three groups (n=32): T0 (control), pumiced; T15, 35% phosphoric acid etched enamel for 15 s; T30, 35% phosphoric acid etched enamel for 30 s. R...

  7. A Novel Absorbing Boundary Condition for the Frequency-DependentFinite-Difference Time-Domain Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new absorbing boundary condition (ABC) for frequency-dependent finite-difference time-domain algorithm for the arbitrary dispersive media is presented. The concepts of the digital systems are introduced to the (FD)2TD method. On the basis of digital filter designing and vector algebra, the absorbing boundary condition under arbitrary angle of incidence are derived. The transient electromagnetic problems in two-dimensions and three-dimensions are calculated and the validity of the ABC is verified.

  8. Individual variation in habituation: behaviour over time toward different stimuli in threespine sticklebacks (Gasterosteus aculeatus)

    OpenAIRE

    Bell, Alison M.; Peeke, Harman V.S.

    2012-01-01

    Habituation, or the relatively permanent waning of a response as a result of repeated stimulation, is a form of behavioural plasticity that allows animals to filter out irrelevant stimuli and to focus selectively on important stimuli. Individuals that fail to habituate might be at a disadvantage if they continue to respond to irrelevant stimuli; therefore, habituation can have adaptive significance. In this study we compared rates of behaviour over time toward three different ecologically-rel...

  9. Accurate finite-difference time-domain simulation of anisotropic media by subpixel smoothing.

    Science.gov (United States)

    Oskooi, Ardavan F; Kottke, Chris; Johnson, Steven G

    2009-09-15

    Finite-difference time-domain methods suffer from reduced accuracy when discretizing discontinuous materials. We previously showed that accuracy can be significantly improved by using subpixel smoothing of the isotropic dielectric function, but only if the smoothing scheme is properly designed. Using recent developments in perturbation theory that were applied to spectral methods, we extend this idea to anisotropic media and demonstrate that the generalized smoothing consistently reduces the errors and even attains second-order convergence with resolution.

  10. Mean Time Between Failure of Ring Arbiter with Requests Differing in Incidences

    OpenAIRE

    Sato, Yoichiro

    1990-01-01

    In asynchronous arbiters, failures may happen, caused by metastable operations. The purpose of this study is to derive a formula to estimate such failures in a ring arbiter as mean time between failures (MTBF), under the condition that incidences of requests issued in all devices are different from each other. The operation of the arbiter is formularized by a markov chain. This chain is used to decide the probability at which each of possible failures contributes to MTBF. The sum of such prob...

  11. Test of high time resolution MRPC with different readout modes for the BESIII upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S. [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Sun, Y.J., E-mail: sunday@ustc.edu.cn [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Li, C., E-mail: licheng@ustc.edu.cn [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Heng, Y.K.; Qian, S. [Institute of High Energy Physics, Chinese Academy of Sciences(IHEP), Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Chen, H.F.; Chen, T.X. [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Dai, H.L. [Institute of High Energy Physics, Chinese Academy of Sciences(IHEP), Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Fan, H.H.; Liu, S.B. [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Liu, S.D.; Jiang, X.S. [Institute of High Energy Physics, Chinese Academy of Sciences(IHEP), Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Shao, M.; Tang, Z.B.; Zhang, H.; Zhao, Z.G. [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China)

    2014-11-01

    In order to further enhance the particle identification capability of the Beijing Spectrometer (BESIII), it is proposed to upgrade the current end-cap time-of-flight (eTOF) detector with multi-gap resistive plate chamber (MRPC). The prototypes, together with the front end electronics (FEE) and time digitizer (TDIG) module have been tested at the E3 line of Beijing Electron Positron Collider (BEPCII) to study the difference between the single and double-end readout MRPC designs. The time resolutions (sigma) of the single-end readout MRPC are 47/53 ps obtained by 600 MeV/c proton/pion beam, while that of the double-end readout MRPC is 40 ps (proton beam). The efficiencies of three MRPC modules tested by both proton and pion beam are better than 98%. For the double-end readout MRPC, no incident position dependence is observed.

  12. Sex differences in relations of muscle power, lung function, and reaction time in athletes.

    Science.gov (United States)

    Gursoy, Recep

    2010-06-01

    In an earlier study, relations of nonverbal abilities with several bodily measures such as height, weight, and lung capacity were observed. The present aim was estimation of associations of muscle power and lung function with simple eye-hand reaction time. Sex differences for muscle power were significant even with the covariates of height, weight, and age included; however, these disappeared for lung functions (forced vital capacity and peak expiratory flow) and reaction time. The effects of leg power, forced vital capacity, and peak expiratory flow on the left eye-hand reaction time were significant after adjustment for height, weight, right- and left-hand powers and age. The positive effect of exercise may be especially associated with the right brain activity or left hand speed.

  13. Nonlinear Least-Squares Time-Difference Estimation from Sub-Nyquist-Rate Samples

    Science.gov (United States)

    Harada, Koji; Sakai, Hideaki

    In this paper, time-difference estimation of filtered random signals passed through multipath channels is discussed. First, we reformulate the approach based on innovation-rate sampling (IRS) to fit our random signal model, then use the IRS results to drive the nonlinear least-squares (NLS) minimization algorithm. This hybrid approach (referred to as the IRS-NLS method) provides consistent estimates even for cases with sub-Nyquist sampling assuming the use of compactly-supported sampling kernels that satisfies the recently-developed nonaliasing condition in the frequency domain. Numerical simulations show that the proposed NLS-IRS method can improve performance over the straight-forward IRS method, and provides approximately the same performance as the NLS method with reduced sampling rate, even for closely-spaced time delays. This enables, given a fixed observation time, significant reduction in the required number of samples, while maintaining the same level of estimation performance.

  14. An Efficient Finite Difference Method for Parameter Sensitivities of Continuous Time Markov Chains

    CERN Document Server

    Anderson, David F

    2011-01-01

    We present an efficient finite difference method for the computation of parameter sensitivities for a wide class of continuous time Markov chains. The motivating class of models, and the source of our examples, are the stochastic chemical kinetic models commonly used in the biosciences, though other natural application areas include population processes and queuing networks. The method is essentially derived by making effective use of the random time change representation of Kurtz, and is no harder to implement than any standard continuous time Markov chain algorithm, such as "Gillespie's algorithm" or the next reaction method. Further, the method is analytically tractable, and, for a given number of realizations of the stochastic process, produces an estimator with substantially lower variance than that obtained using other common methods. Therefore, the computational complexity required to solve a given problem is lowered greatly. In this work, we present the method together with the theoretical analysis de...

  15. Yield performance of upland rice cultivars at different rates and times of nitrogen application

    Directory of Open Access Journals (Sweden)

    José Hildernando Bezerra Barreto

    2012-04-01

    Full Text Available Nitrogen is the most important nutrient for rice (Oryza sativa L yields. This study aimed to evaluate the response of upland rice cultivars to N rate and application times in a randomized block design, in subdivided plots with four replications. The studied factors were five rice cultivars (BRS MG Curinga, BRS Monarca, BRS Pepita, BRS Primavera, and BRS Sertaneja, three application times (100 % at planting, 50 % at planting - 50 % at tillering and 100 % at tillering and four N rates (0, 50, 100, and 150 kg ha-1. All cultivars responded to increased rates and different times of N application, especially BRS Primavera and BRS Sertaneja, which were the most productive when 50 % N rates were applied at sowing and 50 % at tillering. The response of cultivar BRS Monarca to N fertilization was best when 100 % of the fertilizer was applied at tillering.

  16. Differences in time-dependent mechanical properties between extruded and molded hydrogels

    Science.gov (United States)

    Ersumo, N; Witherel, CE; Spiller, KL

    2016-01-01

    The mechanical properties of hydrogels used in biomaterials and tissue engineering applications are critical determinants of their functionality. Despite the recent rise of additive manufacturing, and specifically extrusion-based bioprinting, as a prominent biofabrication method, comprehensive studies investigating the mechanical behavior of extruded constructs remain lacking. To address this gap in knowledge, we compared the mechanical properties and swelling properties of crosslinked gelatin-based hydrogels prepared by conventional molding techniques or by 3D bioprinting using a BioBots Beta pneumatic extruder. A preliminary characterization of the impact of bioprinting parameters on construct properties revealed that both Young's modulus and optimal extruding pressure increased with polymer content, and that printing resolution increased with both printing speed and nozzle gauge. High viability (>95%) of encapsulated NIH 3T3 fibroblasts confirmed the cytocompatibility of the construct preparation process. Interestingly, the Young's moduli of extruded and molded constructs were not different, but extruded constructs did show increases in both the rate and extent of time-dependent mechanical behavior observed in creep. Despite similar polymer densities, extruded hydrogels showed greater swelling over time compared to molded hydrogels, suggesting that differences in creep behavior derived from differences in microstructure and fluid flow. Because of the crucial roles of time-dependent mechanical properties, fluid flow, and swelling properties on tissue and cell behavior, these findings highlight the need for greater consideration of the effects of the extrusion process on hydrogel properties. PMID:27550945

  17. Effects of moonlight on the capturability of frugivorous phyllostomid bats (Chiroptera: Phyllostomidae at different time scales

    Directory of Open Access Journals (Sweden)

    Marco A. R. Mello

    2013-08-01

    Full Text Available Some bat species seem to be lunar phobic, i.e., they avoid flying in bright areas or during bright periods of the night; however, the evidence is still controversial. We think that part of this controversy comes from pooling data on bat captures and moonlight intensity according to broad categories, such as moon phases, which conceal the high variability among nights. Therefore, we used detailed, long-term field data on three phyllostomid bat species, in order to test the hypothesis of lunar phobia at two different time scales: 1 among nights, by pooling data of different nights according to moon phases and testing for differences in the distribution of captures; and 2 within a night, by analyzing the relationship between capturability and moonlight intensity (measured as illuminance in one-hour intervals for 29 individual nights. Although most captures of the studied bat species occurred in the first half of the night, their activity pattern varied largely among nights, and was not always unimodal as commonly assumed. At the larger time scale, all studied bat species showed evidence of lunar phobia, as they were more frequently captured on dark moon phases. Nevertheless, at the smaller time scale, only Carollia perspicillata (Linnaeus, 1758 was less frequently captured on brighter periods of the night. We propose that the unimodal activity pattern assumed for frugivorous phyllostomid bats may be an artifact of data organization, and that activity and lunar phobia are much more variable than previously assumed.

  18. Sound field of thermoacoustic tomography based on a modified finite-difference time-domain method

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chi; WANG Yuanyuan

    2009-01-01

    A modified finite-difference time-domain (FDTD) method is proposed for the sound field simulation of the thermoacoustic tomography (TAT) in the acoustic speed inhomogeneous medium. First, the basic equations of the TAT are discretized to difference ones by the FDTD. Then the electromagnetic pulse, the excitation source of the TAT, is modified twice to eliminate the error introduced by high frequency electromagnetic waves. Computer simulations are carried out to validate this method. It is shown that the FDTD method has a better accuracy than the commonly used time-of-flight (TOF) method in the TAT with the inhomogeneous acoustic speed. The error of the FDTD is ten times smaller than that of the TOF in the simulation for the acoustic speed difference larger than 50%. So this FDTD method is an efficient one for the sound field simulation of the TAT and can provide the theoretical basis for the study of reconstruction algorithms of the TAT in the acoustic heterogeneous medium.

  19. Optimal timing for performing hysterectomy according to different phase of menstrual cycle: Which is best?

    Science.gov (United States)

    Kim, Jeong Jin; Kang, Jun Hyeok; Lee, Kyo Won; Kim, Kye Hyun; Song, Taejong

    2017-05-01

    The aim of this study was to determine whether the different phases of the menstrual cycle could affect operative bleeding in women undergoing laparoscopic hysterectomy. This was a retrospective comparative study. Based on the adjusted day of menstrual cycle, 212 women who underwent laparoscopic hysterectomy were classified into three groups: the follicular phase (n = 51), luteal phase group (n = 125), and menstruation group (n = 36). The primary outcome measure was the operative bleeding. There was no difference in the baseline characteristics of the patients belonging to the three groups. For the groups, there were no significant differences in operative bleeding (p = .469) and change in haemoglobin (p = .330), including operative time, length of hospital stay and complications. The menstrual cycle did not affect the operative bleeding and other parameters. Therefore, no phase of the menstrual cycle could be considered as an optimal timing for performing laparoscopic hysterectomy with minimal operative bleeding. Impact statement What is already known on this subject: the menstrual cycle results in periodic changes in haemostasis and blood flow in the reproductive organs. What the results of this study add: the menstrual cycle did not affect the operative bleeding and other operative parameters during laparoscopic hysterectomy. What the implications are of these findings for clinical practice and/or further research: no phase of the menstrual cycle could be considered as an optimal timing for performing laparoscopic hysterectomy with minimal operative bleeding.

  20. Investigating TIME-GCM Atmospheric Tides for Different Lower Boundary Conditions

    Science.gov (United States)

    Haeusler, K.; Hagan, M. E.; Lu, G.; Forbes, J. M.; Zhang, X.; Doornbos, E.

    2013-12-01

    It has been recently established that atmospheric tides generated in the lower atmosphere significantly influence the geospace environment. In order to extend our knowledge of the various coupling mechanisms between the different atmospheric layers, we rely on model simulations. Currently there exist two versions of the Global Scale Wave Model (GSWM), i.e. GSWM02 and GSWM09, which are used as a lower boundary (ca. 30 km) condition for the Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIME-GCM) and account for the upward propagating atmospheric tides that are generated in the troposphere and lower stratosphere. In this paper we explore the various TIME-GCM upper atmospheric tidal responses for different lower boundary conditions and compare the model diagnostics with tidal results from satellite missions such as TIMED, CHAMP, and GOCE. We also quantify the differences between results associated with GSWM02 and GSWM09 forcing and results of TIMEGCM simulations using Modern-Era Retrospective Analysis for Research and Application (MERRA) data as a lower boundary condition.

  1. Arrival time differences between gravitational waves and electromagnetic signals due to gravitational lensing

    CERN Document Server

    Takahashi, Ryuichi

    2016-01-01

    In this study, we demonstrate that general relativity predicts arrival time differences between gravitational wave (GW) and electromagnetic (EM) signals caused by the wave effects in gravitational lensing. The GW signals can arrive $earlier$ than the EM signals in some cases if the GW/EM signals have passed through a lens, even if both signals were emitted simultaneously by a source. GW wavelengths are much larger than EM wavelengths; therefore, the propagation of the GWs does not follow the laws of geometrical optics, including the Shapiro time delay, if the lens mass is less than approximately $10^5 {\\rm M}_\\odot (f/{\\rm Hz})^{-1}$, where $f$ is the GW frequency. The arrival time difference can reach $\\sim 0.1 \\, {\\rm s} \\, (f/{\\rm Hz})^{-1}$; therefore, it is more prominent for lower GW frequencies. Gravitational lensing imprints a characteristic modulation on a chirp waveform; therefore, we can deduce whether a measured arrival time lag arises from intrinsic source properties or gravitational lensing. Det...

  2. Impact localization on composite structures using time difference and MUSIC approach

    Science.gov (United States)

    Zhong, Yongteng; Xiang, Jiawei

    2017-05-01

    1-D uniform linear array (ULA) has the shortcoming of the half-plane mirror effect, which does not allow discriminating between a target placed above the array and a target placed below the array. This paper presents time difference (TD) and multiple signal classification (MUSIC) based omni-directional impact localization on a large stiffened composite structure using improved linear array, which is able to perform omni-directional 360° localization. This array contains 2M+3 PZT sensors, where 2M+1 PZT sensors are arranged as a uniform linear array, and the other two PZT sensors are placed above and below the array. Firstly, the arrival times of impact signals observed by the other two sensors are determined using the wavelet transform. Compared with each other, the direction range of impact source can be decided in general, 0°to 180° or 180°to 360°. And then, two dimensional multiple signal classification (2D-MUSIC) based spatial spectrum formula using the uniform linear array is applied for impact localization by the general direction range. When the arrival times of impact signals observed by upper PZT is equal to that of lower PZT, the direction can be located in x axis (0°or 180°). And time difference based MUSIC method is present to locate impact position. To verify the proposed approach, the proposed approach is applied to a composite structure. The localization results are in good agreement with the actual impact occurring positions.

  3. Ranging behaviour and time budgets of male wood mice Apodemus sylvaticus in different habitats and seasons.

    Science.gov (United States)

    Corp, N; Gorman, Martyn L; Speakman, John R

    1997-01-01

    Radiotelemetry was used to measure the range areas, activity patterns and time budgets of 21 adult male wood mice (Apodemus sylvaticus) between May 1991 and August 1992. The study investigated variation in range, total distance travelled, speed of movement and time budgets between wood mice in the nonbreeding and breeding seasons in a deciduous woodland (n = 8 and 6 respectively). We also examined habitat differences by estimating these same parameters for wood mice inhabiting maritime sand-dunes in the breeding season (n = 7). Insufficient males of an appropriate mass for radiotracking were captured to study the sand-dune mice in the nonbreeding season. Significant variation was found across both season and site. In the breeding season, in woodland, range areas were 5 times larger than during the nonbreeding season. Wood mice on the sand-dunes exploited ranges 28 times greater than their woodland counterparts. The pattern of variation in range area was parallelled by significant differences in total distances and average speeds travelled per night. Diurnal activity, c. 60 min day(-1), was frequently recorded, at both sites, but only, in the breeding season, which was attributed to the need to forage in order to maintain energy balance. The comparatively lower availability of food on the sand-dunes was considered the main factor explaining the greater range area, total distance moved, speed travelled and level of activity of animals at this site.

  4. Research on the effect of noise at different times of day: Models, methods and findings

    Science.gov (United States)

    Fields, J. M.

    1985-01-01

    Social surveys of residents' responses to noise at different times of day are reviewed. Some of the discrepancies in published reports about the importance of noise at different times of day are reduced when the research findings are classified according to the type of time of day reaction model, the type of time of day weight calculated and the method which is used to estimate the weight. When the estimates of nighttime weights from 12 studies are normalized, it is found that they still disagree, but do not support stronger nighttime weights than those used in existing noise indices. Challenges to common assumptions in nighttime response models are evaluated. Two of these challenges receive enough support to warrant further investigation: the impact of changes in numbers of noise events may be less at night than in the day and nighttime annoyance may be affected by noise levels in other periods. All existing social survey results in which averages of nighttime responses were plotted by nighttime noise levels are reproduced.

  5. Repeatability of the timing of eye-hand coordinated movements across different cognitive tasks.

    Science.gov (United States)

    de Boer, C; van der Steen, J; Schol, R J; Pel, J J M

    2013-08-15

    Quantification of eye-hand coordinated behaviour is a relatively new tool to study neurodegeneration in humans. Its sensitivity depends on the assessment of different behavioural strategies, multiple task testing and repeating tasks within one session. However, large numbers of repetition trials pose a significant burden on subjects. To introduce this method in large-scale population studies, it is necessary to determine whether reducing the number of task repetitions, which will lower subject burden, still leads to acceptable measurement accuracy. The objective of this study was to investigate the validity and reliability of eye-hand coordination outcome parameters in eight healthy volunteers using a test-retest approach. Subjects were assessed during a shortened test procedure consisting of eight repetitions of three behavioural tasks: a reflex-based tapping task, a planning-based tapping task and a memory-based tapping task. Eye-hand coordination was quantified in terms of timing (eye and hand latencies), kinematics and accuracy. Eye and hand latencies were found within a normal range (between 150 and 450ms). A paired samples t-test revealed no differences in timing parameters between the first and second measurements. It was concluded that eight trial repetitions are sufficient for quantifying eye-hand coordination in terms of timing, kinematics and accuracy. This approach demonstrates the testing of multiple visuomotor behaviours within a reasonable time span of a few minutes per task.

  6. Measuring DHEA-S in saliva: time of day differences and positive correlations between two different types of collection methods

    Directory of Open Access Journals (Sweden)

    Klein Laura C

    2010-07-01

    Full Text Available Abstract Background The anabolic steroid, dehydroepiandosterone sulfate (DHEA-S, is secreted from the adrenal cortex. It plays a significant role in the body as a precursor to sex steroids as well as a lesser known role in the hypothalamic pituitary adrenal axis (HPA response to stress. DHEA-S can be measured reliably in saliva, making saliva collection a valuable tool for health research because it minimizes the need for invasive sampling procedures (e.g., blood draws. Typical saliva collection methods include the use of plain cotton swab collection devices (e.g., Salivette® or passive drool. There has been some speculation that the plain saliva cotton collection device may interfere with determination of DHEA-S by enzyme immunoassay (EIA bringing this saliva collection method into question. Because of the increasing popularity of salivary biomarker research, we sought to determine whether the cotton swab interferes with DHEA-S determination through EIA techniques. Findings Fifty-six healthy young adult men and women aged 18-30 years came to the lab in the morning (0800 hrs; 14 men, 14 women or late afternoon (1600 hrs; 14 men, 14 women and provided saliva samples via cotton Salivette and passive drool. Passive drool collection was taken first to minimize particle cross contamination from the cotton swab. Samples were assayed for DHEA-S in duplicate using a commercially available kit (DSL, Inc., Webster, TX. DHEA-S levels collected via Salivette and passive drool were positively correlated (r = + 0.83, p Conclusions Results suggest that DHEA-S can be measured accurately using passive drool or cotton Salivette collection methods. Results also suggest that DHEA-S levels change across the day and that future studies need to take this time of day difference into account when measuring DHEA-S.

  7. One-shot or Embedded? Assessing Different Delivery Timing for Information Resources Relevant to Assignments

    Directory of Open Access Journals (Sweden)

    Megan Sapp Nelson

    2013-03-01

    Full Text Available Objective – This study aims to determine if the timing of library in-class presentations makes a difference in the type and quality of resources students use for each of four assignments in an introductory speech class. This comparison of content delivery timing contrasts a single, 50-minute lecture early in the semester with four approximately 12-minute lectures offered just before each assignment.Methods – First-year engineering students taking Fundamentals of Speech Communication provide the study group. Each speech assignment requires students to turn in an outline and list of references. The list of references for each student was given to the librarians, after the assignments were appropriately anonymized, for analysis of resource type, quality of resource, and completeness of citation. Researchers coded arandom sample of bibliographies from the assignments using a framework to identify resource type (book, periodical, Web, facts & figures, unknown and quality, based on intended audience and purpose (scholarly, entertainment, persuasion/bias, and compared them to each other to determine if a difference is evident. The authors coordinated what material would be presented to the students to minimize variation between the sections.Results – The study found a statistically significant difference between groups of students, demonstrating that the frequent, short library instruction sessions produce an increased use of high-quality content. Similarly, the sections with multiple library interactions show more use of periodicals than websites, while completeness of references is not significantly different across teaching methods.Conclusions – More frequent and timely interaction between students and library instruction increases the quality of sources used and the completeness of the citations written. While researchers found statistically significant differences, the use of a citation coding framework developed for specific engineering

  8. Changes in setting time of alginate impression material with different water temperature

    Directory of Open Access Journals (Sweden)

    Decky J. Indrani

    2013-03-01

    Full Text Available Background: Previous studies showed that setting process of alginates can be influenced by temperature. Purpose: To determine the changes in setting time due to differences in water temperature and to determine the correlation between water temperature and the setting time. Methods: Seven groups of dough alginate were prepared by mixing alginate powder and water, each using a temperature between 13° C–28° C with a interval of 2.5° C. A sample mold (Θ = 30 mm, t = 16 mm was placed on a flat plate and filled with doug alginate. Immediately the flat end of a polished acrylic rod was placed in contact with the surface of dough alginate. Setting time of alginat was measured from the starting of the mix to the time when the alginate does not adhere to the end of the rod. Setting time alginate data were analyzed using one way ANOVA, LSD and Pearson. Results: Setting time of alginate with water temperature between 13° C–28° C were 87 to 119.4 seconds and were significantly different (p < 0.01. The setting time between group were also significantly different (p<0.01. There was an inverse correlation between water temperature and the setting time (r = -0.968. Conclusion: Water temperature between 13° C–28°C with a difference of 2.5° C produced significant differences in alginate setting time; the lower the water temperature being used the longer the setting time was produced.Latar belakang: Penelitian-penelitian sebelumnya menunjukkan bahwa proses pengerasan alginat dapat dipengaruhi oleh suhu. Tujuan: Mengetahui perubahan waktu pengerasan alginat akibat perbedaan suhu air serta mengetahui hubungan antara suhu air dan waktu pengerasan. Metode: Tujuh kelompok adonan alginat yang dipersiapkan dengan mencampur bubuk alginat dan air, masingmasing menggunakan suhu antara 13°C–28° C dengan interval 2,5° C. Pengukuran waktu pengerasan alginat dilakukan sesuai dengan spesifikasi ADA no.18. Sebuah cetakan sampel terbuat dari pralon berbentuk

  9. Acute effect of different time periods of passive static stretching on the hamstring flexibility.

    Science.gov (United States)

    Cini, Anelize; de Vasconcelos, Gabriela Souza; Lima, Claudia Silveira

    2017-01-01

    Several factors are associated with the presence of chronic low back pain; one of them is the flexibility of the hamstring muscles that influences the posture of the pelvic spine. Investigate the influence of two different time periods of passive static stretching on the flexibility of the hamstring. Forty-six physiotherapy students were divided into two groups performing stretching exercises: 30 s and 60 s duration. The collections consisted of: (1) pre-test: evaluation of the flexibility of the hip and knee, using a manual goniometer by means of the following tests: Straight Leg Raise Test (SLR), Passive Hip Flexion Test (PHFT) and Modified Knee Extension Test (MKET), (2) intervention: stretching with different runtimes, (3) post-test: reappraisal of flexibility, conducted immediately after the intervention. Significant difference was observed intra groups, group that did stretching exercises lasting 30 seconds (G30) (SLR p = 0.000. PHFT p = 0.003 and MKET p = 0.000) and group that did stretching exercises lasting 60 seconds (G60) (SLR p = 0.000. PHFT p = 0.001 and MKET p = 0.002). Comparing the groups, no significant difference was found (SLR p = 0.307; PHFT p = 0.904; MKET p = 0.132). Thus it can be inferred that 30 seconds are sufficient for increased flexibility of young women. Therefore the time-treatment sessions can be optimized. Only the acute effect of stretching was observed; further investigation of the long-term effect is required.

  10. Effects of Low Temperature on Freezing Injury of Various Winter Wheat Cultivars at Different Sowing Time

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Freezing injury is one of the major disasters for the production of winter wheat in the North China Plain, which leads to a significant decrease of wheat yield. This study was conducted to investigate the impact of subfreezing temperature on freezing injury of various winter wheat cultivars at different sowing time. Three wheat cultivars, including Zhengmai 9023, Wanmai 48 and Wanmai 50, were sowed on 25 September and 5 October, respectively. Plant anatomy was applied to investi- gate the impact of subfreezing temperature on cells of three wheat cultivars, results showed that severe plasmolysis occurred in wheat sowed earlier suddenly encoun- tered subfreezing temperature without cold acclimation, compared with wheat sowed at proper sowing time. The degree of plasmolysis of different cultivars and tissues of wheat had significant differences and showed positive correlation with subfreezing temperature. Wanmai 50 had the highest cold resistance compared with Zhengmai 9023 and Wanmai 48, and there was no significant difference between Zhengmai 9023 and Wanmai 48. This study concluded that wheat cold resistance may be im- proved by adopting proper cultivars and sowing dates.

  11. Difference resonances in a controlled van der Pol-Duffing oscillator involving time delay

    Energy Technology Data Exchange (ETDEWEB)

    Ji, J.C. [Faculty of Engineering, University of Technology, Sydney, Level 20, Building 1, PO Box 123, Broadway, NSW 2007 (Australia)], E-mail: jin.ji@uts.edu.au; Zhang, N.; Gao Wei [Faculty of Engineering, University of Technology, Sydney, Level 20, Building 1, PO Box 123, Broadway, NSW 2007 (Australia)

    2009-10-30

    A non-resonant interaction of two Hopf bifurcations may appear after the trivial solution of a controlled van der Pol-Duffing oscillator without external excitation loses its stability, when two critical time delays corresponding to two Hopf bifurcations have the same value. In the vicinity of the non-resonant Hopf bifurcations, the presence of a periodic excitation in the controlled oscillator can induce difference resonances in the forced response, when the forcing frequency and the frequencies of the two Hopf bifurcations satisfy certain relationships. It is found that the frequency response curves of the controlled system under difference resonances are an isolated closed curve. The difference resonance response may admit two stable motions on a three-dimensional torus consisting of three frequencies. Illustrative examples are given to show the quasi-periodic motions.

  12. Differences in Crenate Broomrape Parasitism Dynamics on Three Legume Crops Using a Thermal Time Model

    Science.gov (United States)

    Pérez-de-Luque, Alejandro; Flores, Fernando; Rubiales, Diego

    2016-01-01

    Root parasitic weeds are a major limiting production factor in a number of crops, and control is difficult. Genetic resistance and chemical control lead the fight, but without unequivocal success. Models that help to describe and even predict the evolution of parasitism underground are a valuable tool for herbicide applications, and even could help in breeding programs. Legumes are heavily affected by Orobanche crenata (crenate broomrape) in the Mediterranean basin. This work presents a descriptive model based on thermal time and correlating growing degree days (GDD) with the different developmental stages of the parasite. The model was developed in three different legume crops (faba bean, grass pea and lentil) attacked by crenate broomrape. The developmental stages of the parasite strongly correlated with the GDD and differences were found depending on the host crop. PMID:28018421

  13. Sex differences in voice onset time: A developmental study of phonetic context effects in British English

    Science.gov (United States)

    Whiteside, Sandra P.; Henry, Luisa; Dobbin, Rachel

    2004-08-01

    Voice onset time (VOT) data for the plosives /p b t d k g/ in two vowel contexts (eye opena) for 5 groups of 46 boys and girls aged 5; 8 (5 years, 8 months) to 13;2 years were investigated to examine patterns of sex differences. Results indicated that there was some evidence of females displaying longer VOT values than the males. In addition, these were found to be most marked for the data of the 13;2-year olds. Furthermore, the sex differences in the VOT values displayed phonetic context effects. For example, the greatest sex differences were observed for the voiceless plosives, and within the context of the vowel /i/.

  14. Measurement invariance of the perceived stress scale and latent mean differences across gender and time.

    Science.gov (United States)

    Barbosa-Leiker, Celestina; Kostick, Marylynne; Lei, Ming; McPherson, Sterling; Roper, Virginia; Hoekstra, Trynke; Wright, Bruce

    2013-08-01

    Measurement invariance of the 2-factor model of the Perceived Stress Scale--10-item version (Cohen & Williamson, 1988) was tested across men and women at two time points and in the combined total sample over a 2-year time frame (n = 871). Measurement invariance results indicated that the scale measured the latent factors, stress and counter-stress, equivalently in men and women and over time. With measurement invariance demonstrated, differences in latent means were tested. Results indicated that men had lower levels of frequencies of stressors, and at one time point, higher levels of counter-stress, when compared with women. When examining change in frequencies of stressors and counter-stress over 2 years with the combined male and female sample, stressors remained stable, yet counter-stress increased over time. These findings may aid in the interpretation of results when examining stressors and counter-stress in clinical samples where one would expect stress to increase, whereas positive psychological states decrease.

  15. Simple reaction time and decision making performance after different physical workloads: an examination with elite athletes

    Directory of Open Access Journals (Sweden)

    Recep Ali Özdemir

    2010-09-01

    Full Text Available The purpose of the present study was to investigate effects of both local and general physical fatigue on visual simple and visual choice reaction time of elite level athletes. 15 male and 3 female national Muay-Thai athletes (Mage = 21.55, SD= 3.47 who participated at least 5 training sessions per week volunteered to participate present study. Subjects were asked to perform Wingate anaerobic test on a mechanically braked cycle ergometer (834 E, Monark to induce general fatigue. Hand grip dynamometer was used for resistance exercises to induce local fatigue. Simple, two-choice and three-choice visual reaction times were measured at resting, after local and general physical fatigue conditions both on right and left hands, respectively. The results of repeated measure ANOVAs yielded that compared to resting conditions simple reaction time significantly increased after inducing the local and general physical fatigue on both hands. On the other hand, although two-choice and three-choice reaction time mean scores increased from resting to both general and local physical fatigue conditions, these increments were not statistically different among measurements. It was concluded that both dynamic and resistance exercise induced fatigue may seems to lengthen only simple reaction time and did not affect decision making processes of elite level Muay-Thai athletes.

  16. Manufacturing Enhancement through Reduction of Cycle Time using Different Lean Techniques

    Science.gov (United States)

    Suganthini Rekha, R.; Periyasamy, P.; Nallusamy, S.

    2017-08-01

    In recent manufacturing system the most important parameters in production line are work in process, TAKT time and line balancing. In this article lean tools and techniques were implemented to reduce the cycle time. The aim is to enhance the productivity of the water pump pipe by identifying the bottleneck stations and non value added activities. From the initial time study the bottleneck processes were identified and then necessary expanding processes were also identified for the bottleneck process. Subsequently the improvement actions have been established and implemented using different lean tools like value stream mapping, 5S and line balancing. The current state value stream mapping was developed to describe the existing status and to identify various problem areas. 5S was used to implement the steps to reduce the process cycle time and unnecessary movements of man and material. The improvement activities were implemented with required suggested and the future state value stream mapping was developed. From the results it was concluded that the total cycle time was reduced about 290.41 seconds and the customer demand has been increased about 760 units.

  17. Effect of different aerodynamic time trial cycling positions on muscle activation and crank torque.

    Science.gov (United States)

    Fintelman, D M; Sterling, M; Hemida, H; Li, F-X

    2016-05-01

    To reduce air resistance, time trial cyclists and triathletes lower their torso angle. The aim of this study was to investigate the effect of lowering time trial torso angle positions on muscle activation patterns and crank torque coordination. It was hypothesized that small torso angles yield a forward shift of the muscle activation timing and crank torque. Twenty-one trained cyclists performed three exercise bouts at 70% maximal aerobic power in a time trial position at three different torso angles (0°, 8°, and 16°) at a fixed cadence of 85 rpm. Measurements included surface electromyography, crank torques and gas exchange. A significant increase in crank torque range and forward shift in peak torque timing was found at smaller torso angles. This relates closely with the later onset and duration of the muscle activation found in the gluteus maximus muscle. Torso angle effects were only observed in proximal monoarticular muscles. Moreover, all measured physiological variables (oxygen consumption, breathing frequency, minute ventilation) were significantly increased with lowering torso angle and hence decreased the gross efficiency. The findings provide support for the notion that at a cycling intensity of 70% maximal aerobic power, the aerodynamic gains outweigh the physiological/biomechanical disadvantages in trained cyclists.

  18. Difference-based clustering of short time-course microarray data with replicates

    Directory of Open Access Journals (Sweden)

    Kim Jihoon

    2007-07-01

    Full Text Available Abstract Background There are some limitations associated with conventional clustering methods for short time-course gene expression data. The current algorithms require prior domain knowledge and do not incorporate information from replicates. Moreover, the results are not always easy to interpret biologically. Results We propose a novel algorithm for identifying a subset of genes sharing a significant temporal expression pattern when replicates are used. Our algorithm requires no prior knowledge, instead relying on an observed statistic which is based on the first and second order differences between adjacent time-points. Here, a pattern is predefined as the sequence of symbols indicating direction and the rate of change between time-points, and each gene is assigned to a cluster whose members share a similar pattern. We evaluated the performance of our algorithm to those of K-means, Self-Organizing Map and the Short Time-series Expression Miner methods. Conclusions Assessments using simulated and real data show that our method outperformed aforementioned algorithms. Our approach is an appropriate solution for clustering short time-course microarray data with replicates.

  19. Comparison of different nonlinear solvers for 2D time-implicit stellar hydrodynamics

    CERN Document Server

    Viallet, Maxime; Walder, Rolf

    2013-01-01

    Time-implicit schemes are attractive since they allow numerical time steps that are much larger than those permitted by the Courant-Friedrich-Lewy criterion characterizing time-explicit methods. This advantage comes, however, with a cost: the solution of a system of nonlinear equations is required at each time step. In this work, the nonlinear system results from the discretization of the hydrodynamical equations with the Crank-Nicholson scheme. We compare the cost of different methods, based on Newton-Raphson iterations, to solve this nonlinear system, and benchmark their performances against time-explicit schemes. Since our general scientific objective is to model stellar interiors, we use as test cases two realistic models for the convective envelope of a red giant and a young Sun. Focusing on 2D simulations, we show that the best performances are obtained with the quasi-Newton method proposed by Broyden. Another important concern is the accuracy of implicit calculations. Based on the study of an idealized...

  20. Regional differences in seasonal timing of rainfall discriminate between genetically distinct East African giraffe taxa.

    Directory of Open Access Journals (Sweden)

    Henri A Thomassen

    Full Text Available Masai (Giraffa tippelskirchi, Reticulated (G. reticulata and Rothschild's (G. camelopardalis giraffe lineages in East Africa are morphologically and genetically distinct, yet in Kenya their ranges abut. This raises the question of how divergence is maintained among populations of a large mammal capable of long-distance travel, and which readily hybridize in zoos. Here we test four hypotheses concerning the maintenance of the phylogeographic boundaries among the three taxa: 1 isolation-by-distance; 2 physical barriers to dispersal; 3 general habitat differences resulting in habitat segregation; or 4 regional differences in the seasonal timing of rainfall, and resultant timing of browse availability. We used satellite remotely sensed and climate data to characterize the environment at the locations of genotyped giraffes. Canonical variate analysis, random forest algorithms, and generalized dissimilarity modelling were employed in a landscape genetics framework to identify the predictor variables that best explained giraffes' genetic divergence. We found that regional differences in the timing of precipitation, and resulting green-up associated with the abundance of browse, effectively discriminate between taxa. Local habitat conditions, topographic and human-induced barriers, and geographic distance did not aid in discriminating among lineages. Our results suggest that selection associated with regional timing of events in the annual climatic cycle may help maintain genetic and phenotypic divergence in giraffes. We discuss potential mechanisms of maintaining divergence, and suggest that synchronization of reproduction with seasonal rainfall cycles that are geographically distinct may contribute to reproductive isolation. Coordination of weaning with green-up cycles could minimize the costs of lactation and predation on the young. Our findings are consistent with theory and empirical results demonstrating the efficacy of seasonal or phenologically

  1. Regional differences in seasonal timing of rainfall discriminate between genetically distinct East African giraffe taxa.

    Science.gov (United States)

    Thomassen, Henri A; Freedman, Adam H; Brown, David M; Buermann, Wolfgang; Jacobs, David K

    2013-01-01

    Masai (Giraffa tippelskirchi), Reticulated (G. reticulata) and Rothschild's (G. camelopardalis) giraffe lineages in East Africa are morphologically and genetically distinct, yet in Kenya their ranges abut. This raises the question of how divergence is maintained among populations of a large mammal capable of long-distance travel, and which readily hybridize in zoos. Here we test four hypotheses concerning the maintenance of the phylogeographic boundaries among the three taxa: 1) isolation-by-distance; 2) physical barriers to dispersal; 3) general habitat differences resulting in habitat segregation; or 4) regional differences in the seasonal timing of rainfall, and resultant timing of browse availability. We used satellite remotely sensed and climate data to characterize the environment at the locations of genotyped giraffes. Canonical variate analysis, random forest algorithms, and generalized dissimilarity modelling were employed in a landscape genetics framework to identify the predictor variables that best explained giraffes' genetic divergence. We found that regional differences in the timing of precipitation, and resulting green-up associated with the abundance of browse, effectively discriminate between taxa. Local habitat conditions, topographic and human-induced barriers, and geographic distance did not aid in discriminating among lineages. Our results suggest that selection associated with regional timing of events in the annual climatic cycle may help maintain genetic and phenotypic divergence in giraffes. We discuss potential mechanisms of maintaining divergence, and suggest that synchronization of reproduction with seasonal rainfall cycles that are geographically distinct may contribute to reproductive isolation. Coordination of weaning with green-up cycles could minimize the costs of lactation and predation on the young. Our findings are consistent with theory and empirical results demonstrating the efficacy of seasonal or phenologically dictated

  2. Dimensional Stability of Two Polyvinyl Siloxane Impression Materials in Different Time Intervals

    Directory of Open Access Journals (Sweden)

    Aalaei Sh

    2015-12-01

    Full Text Available Statement of the Problem: Dental prosthesis is usually made indirectly; there- fore dimensional stability of the impression material is very important. Every few years, new impression materials with different manufacturers’ claims regarding their better properties are introduced to the dental markets which require more research to evaluate their true dimensional changes. Objectives: The aim of this study was to evaluate dimensional stability of additional silicone impression material (Panasil® and Affinis® in different time intervals. Materials and Methods: In this experimental study, using two additional silicones (Panasil® and Affinis®, we made sixty impressions of standard die in similar conditions of 23 °C and 59% relative humidity by a special tray. The die included three horizontal and two vertical lines that were parallel. The vertical line crossed the horizontal ones at a point that served as reference for measurement. All impressions were poured with high strength dental stone. The dimensions were measured by stereo-microscope by two examiners in three interval storage times (1, 24 and 168 hours.The data were statistically analyzed using t-test and ANOVA. Results: All of the stone casts were larger than the standard die. Dimensional changes of Panasil and Affinis were 0.07%, 0.24%, 0.27% and 0.02%, 0.07%, 0.16% after 1, 24 and 168 hours, respectively. Dimensional change for two impression materials wasn’t significant in the interval time, expect for Panasil after one week (p = 0.004. Conclusions: According to the limitations of this study, Affinis impressions were dimensionally more stable than Panasil ones, but it was not significant. Dimensional change of Panasil impression showed a statistically significant difference after one week. Dimensional changes of both impression materials were based on ADA standard limitation in all time intervals (< 0.5%; therefore, dimensional stability of this impression was accepted at least

  3. Evaluation of cytotoxicity and degree of conversion of orthodontic adhesives over different time periods

    Directory of Open Access Journals (Sweden)

    Matheus Melo Pithon

    2010-06-01

    Full Text Available As new orthodontic resin adhesives continue to be marketed, rapid and sensitive tests for examining their toxic effects at the ' cell and tissue level ' are needed because patient safety has been identifi ed as a legal concept. The objective of the present study was to evaluate the cytotoxicity and degree of monomer conversion of orthodontic adhesives over different time periods. Seven adhesives: Transbond® XT, Transbond® Color Change, Quick Cure, EagleBond, Orthobond®, Fill Mágic® and Biofix® were evaluated for their cytotoxicity in L929 fibroblastic cells and for their degree of monomer conversion over different time periods. Three control groups were also analysed: Positive control (C+, consisting of Tween 80 cell detergent; Negative control (C-, consisting of PBS; and cell control (CC, consisting of cells exposed to any material. The dye-uptake technique that involves the absorption of a neutral red dye in viable cells was used for the cytotoxicity evaluation and the degree of conversion was evaluated using spectroscopy with infrared. The results showed the cytotoxicity of the adhesives at 24, 48, 72 and 168 hours. At these times, the viability values presented for these materials were statistically different from the groups CC and C- (p 0.05. In the monomer conversions there was a percentage increase of monomer conversion from 24 to 72 hours. A direct correlation could be observed between cytotoxicity and monomer conversions. From this work it can be concluded that all adhesives evaluated are cytotoxic at the times of 24, 48 and 72 hours. Monomers continued conversion even after photopolymerization had stopped.

  4. Concentration of Umami Compounds in Pork Meat and Cooking Juice with Different Cooking Times and Temperatures.

    Science.gov (United States)

    Rotola-Pukkila, Minna K; Pihlajaviita, Seija T; Kaimainen, Mika T; Hopia, Anu I

    2015-12-01

    This study examined the concentrations of umami compounds in pork loins cooked at 3 different temperatures and 3 different lengths of cooking times. The pork loins were cooked with the sous vide technique. The free amino acids (FAAs), glutamic acid and aspartic acid; the 5'-nucleotides, inosine-5'-monophosphate (IMP) and adenosine-5'-monophosphate (AMP); and corresponding nucleoside inosine of the cooked meat and its released juice were determined by high-performance liquid chromatography. Under the experimental conditions used, the cooking temperature played a more important role than the cooking time in the concentration of the analyzed compounds. The amino acid concentrations in the meat did not remain constant under these experimental conditions. The most notable effect observed was that of the cooking temperature and the higher amino acid concentrations in the released juice of meat cooked at 80 °C compared with 60 and 70 °C. This is most likely due to the heat induced hydrolysis of proteins and peptides releasing water soluble FAAs from the meat into the cooking juice. In this experiment, the cooking time and temperature had no influence on the IMP concentrations observed. However, the AMP concentrations increased with the increasing temperature and time. This suggests that the choice of time and temperature in sous vide cooking affects the nucleotide concentration of pork meat. The Sous vide technique proved to be a good technique to preserve the cooking juice and the results presented here show that cooking juice is rich in umami compounds, which can be used to provide a savory or brothy taste. © 2015 Institute of Food Technologists®

  5. Diabetes patients show different time-course of myocardial perfusion improvement after coronary artery bypass grafting

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. J.; Seok, J. W.; Eo, J. S. [Seoul National University Hospital, Seoul (Korea, Republic of)] (and others)

    2005-07-01

    Diabetes mellitus is an independent risk factor of cardiovascular disease. Diabetes is known to cause microangiopathy. The microangiopathy is hardly detectable on the coronary angiography. Myocardial perfusion imaging shows the resultant perfusion status which reflects the microangiopathy. For patients who underwent revascularization, the microangiopathy could affect the myocardial perfusion improvement. Diabetes patients probably experience the different myocardial perfusion improvement as compared to the non-diabetes patients although they have similar angiographic findings. The aim of this study is to find out whether there is a time-course difference of perfusion improvement between the diabetes and non diabetes patients who showed patent angiographic findings after coronary artery grafting surgery (CABG). A total of 129 patients who underwent coronary artery bypass grafting surgery were enrolled in this study. Myocardial SPECTs performed at previous, short-term (3 month), and mid-term (1 year) to CABG. One-year follow up angiography was done 411{+-}121 days after surgery. Graft patency was determined according to the FitzGibbon et al. Segments were assigned to vascular territories using a 20 segment model. The segments of excellent patency were included in this study. Time course differences of concerned segments were analyzed using RMANOVA. The number of segments enrolled was 764 of diabetes and 1083 of non-diabetes. At short-term follow up, reversibility score was 2.8{+-}8.1% in diabetes and 0.3{+-}7.5% in non-diabetes. At long-term follow up, reversibility score was 1.8{+-}8.0% in diabetes and 0.1{+-}7.3% in non-diabetes. The time-course of reversibility score was significantly different between the diabetes and non diabetes (p<0.001) Diabetic segments showed high residual reversibility score than non-diabetic segments after CABG although the angiographic finding was patent in both groups. This result is maybe attributable to microangiopathy induced by

  6. A time for learning and a time for sleep: the effect of sleep deprivation on contextual fear conditioning at different times of the day.

    Science.gov (United States)

    Hagewoud, Roelina; Whitcomb, Shamiso N; Heeringa, Amarins N; Havekes, Robbert; Koolhaas, Jaap M; Meerlo, Peter

    2010-10-01

    Sleep deprivation negatively affects memory consolidation, especially in the case of hippocampus-dependent memories. Studies in rodents have shown that 5 hours of sleep deprivation immediately following footshock exposure selectively impairs the formation of a contextual fear memory. In these studies, both acquisition and subsequent sleep deprivation were performed in the animals' main resting phase. However, in everyday life, subjects most often learn during their active phase. Here we examined the effects of sleep deprivation on memory consolidation for contextual fear in rats when the task was performed at different times of the day, particularly, at the beginning of the resting phase or right before the onset of the active phase. Results show that sleep deprivation immediately following training affects consolidation of contextual fear, independent of time of training. However, in the resting phase memory consolidation was impaired by 6 hours of posttraining sleep deprivation, whereas, in the active phase, the impairment was only seen after 12 hours of sleep deprivation. Since rats sleep at least twice as much during the resting phase compared with the active phase, these data suggest that the effect of sleep deprivation depends on the amount of sleep that was lost. Also, control experiments show that effects of sleep deprivation were not related to the amount of stimulation the animals received and were therefore not likely an indirect effect of the sleep-deprivation method. These results support the notion that sleep immediately following acquisition, independent of time of day, promotes memory consolidation and that sleep deprivation may disrupt this process depending on the amount of sleep that is lost.

  7. Gender, Parenthood and Wage Differences: The Importance of Time-Consuming Job Characteristics.

    Science.gov (United States)

    Magnusson, Charlotta; Nermo, Magnus

    2017-01-01

    Using data from the Swedish Level of Living Survey (2000, 2010), we investigate how the gender wage gap varies with occupational prestige and family status and also examine the extent to which this gap is explained by time-consuming working conditions. In addition, we investigate whether there is an association between parenthood, job characteristics and wage (as differentiated by gender). The analyses indicate that there are gender differences regarding prestige-based pay-offs among parents that are partly explained by fathers' greater access to employment characterized by time-consuming conditions. Separate analyses for men and women demonstrate the presence of a marriage wage premium for both genders, although only men have a parenthood wage premium. This fatherhood premium is however only present in high-prestigious occupations. Compared with childless men, fathers are also more advantaged in terms of access to jobs with time-consuming working conditions, but the wage gap between fathers and childless men is not explained by differences in access to such working conditions.

  8. Two-dimensional time-domain finite-difference modeling for viscoelastic seismic wave propagation

    Science.gov (United States)

    Fan, Na; Zhao, Lian-Feng; Xie, Xiao-Bi; Ge, Zengxi; Yao, Zhen-Xing

    2016-09-01

    Real Earth media are not perfectly elastic. Instead, they attenuate propagating mechanical waves. This anelastic phenomenon in wave propagation can be modeled by a viscoelastic mechanical model consisting of several standard linear solids. Using this viscoelastic model, we approximate a constant Q over a frequency band of interest. We use a four-element viscoelastic model with a trade-off between accuracy and computational costs to incorporate Q into 2-D time-domain first-order velocity-stress wave equations. To improve the computational efficiency, we limit the Q in the model to a list of discrete values between 2 and 1000. The related stress and strain relaxation times that characterize the viscoelastic model are pre-calculated and stored in a database for use by the finite-difference calculation. A viscoelastic finite-difference scheme that is second order in time and fourth order in space is developed based on the MacCormack algorithm. The new method is validated by comparing the numerical result with analytical solutions that are calculated using the generalized reflection/transmission coefficient method. The synthetic seismograms exhibit greater than 95 per cent consistency in a two-layer viscoelastic model. The dispersion generated from the simulation is consistent with the Kolsky-Futterman dispersion relationship.

  9. The relative effect of noise at different times of day: An analysis of existing survey data

    Science.gov (United States)

    Fields, J. M.

    1986-01-01

    This report examines survey evidence on the relative impact of noise at different times of day and assesses the survey methodology which produces that evidence. Analyses of the regression of overall (24-hour) annoyance on noise levels in different time periods can provide direct estimates of the value of the parameters in human reaction models which are used in environmental noise indices such as LDN and CNEL. In this report these analyses are based on the original computer tapes containing the responses of 22,000 respondents from ten studies of response to noise in residential areas. The estimates derived from these analyses are found to be so inaccurate that they do not provide useful information for policy or scientific purposes. The possibility that the type of questionnaire item could be biasing the estimates of the time-of-day weightings is considered but not supported by the data. Two alternatives to the conventional noise reaction model (adjusted energy model) are considered but not supported by the data.

  10. Soft sensor modelling by time difference, recursive partial least squares and adaptive model updating

    Science.gov (United States)

    Fu, Y.; Yang, W.; Xu, O.; Zhou, L.; Wang, J.

    2017-04-01

    To investigate time-variant and nonlinear characteristics in industrial processes, a soft sensor modelling method based on time difference, moving-window recursive partial least square (PLS) and adaptive model updating is proposed. In this method, time difference values of input and output variables are used as training samples to construct the model, which can reduce the effects of the nonlinear characteristic on modelling accuracy and retain the advantages of recursive PLS algorithm. To solve the high updating frequency of the model, a confidence value is introduced, which can be updated adaptively according to the results of the model performance assessment. Once the confidence value is updated, the model can be updated. The proposed method has been used to predict the 4-carboxy-benz-aldehyde (CBA) content in the purified terephthalic acid (PTA) oxidation reaction process. The results show that the proposed soft sensor modelling method can reduce computation effectively, improve prediction accuracy by making use of process information and reflect the process characteristics accurately.

  11. Age differences in multiple outcome measures of time-based prospective memory.

    Science.gov (United States)

    Mäntylä, Timo; Missier, Fabio Del; Nilsson, Lars-Göran

    2009-11-01

    This study examined time-based prospective memory performance in relation to age, monitoring strategy, response accuracy, and dual-task demands. Young, middle-aged and older adults (N = 115) completed a prospective memory task, in which they indicated the passing of time every 5 min while listening to a short story (low task demands) or completing a series of cognitive tasks (high task demands). Young and older adults showed similar patterns of monitoring behavior, with low rates of clock checking during the early phase of each 5-min interval, followed by linearly accelerating monitoring functions. However, to obtain the same level of prospective memory performance older adults needed more frequent clock checks than young adults. Furthermore, older adults' compensatory monitoring strategy was associated with an additional cost in primary task performance. Finally, increased primary task demands shifted age differences in prospective memory from monitoring frequency to response accuracy. These findings suggest that goal-directed behavior requires efficient task coordination and resource allocation, and that age-related differences in time-based prospective memory should be evaluated by using multiple outcome measures.

  12. Two pulse-coupled non-identical, frequency-different BZ oscillators with time delay.

    Science.gov (United States)

    Lavrova, Anastasia I; Vanag, Vladimir K

    2014-04-14

    Two non-identical, frequency-different pulse-coupled oscillators with time delay have been systematically studied using four-variable model of the Belousov-Zhabotinsky (BZ) reaction at mutual inhibitory, mutual excitatory, and mixed excitatory-inhibitory types of coupling. Different resonances like 1 : 2, 2 : 3, 1 : 3, etc., as well as complex rhythms and abrupt changes between them occur depending on the coupling strengths, time delay, and frequency ratio. Analogously to in-phase and anti-phase oscillations for 1 : 1 resonance, a similar phase locking exists for 1 : 2 resonance in the case of inhibitory coupling. For excitatory coupling, a bursting regime is found. The number of spikes in a single burst can be tuned by both the frequency ratio and time delay. For excitatory-inhibitory coupling, a region where one oscillator is suppressed (OS zone) has been found. Boundary of the OS zone depends on the frequency ratio. For weakly coupled oscillators, Farey sequence has been found for excitatory-inhibitory and mutual excitatory coupling.

  13. Residence times in shallow waters help explain regional differences in Wadden Sea eutrophication

    Science.gov (United States)

    Schwichtenberg, Fabian; Callies, Ulrich; van Beusekom, Justus E. E.

    2016-11-01

    Regional variations in eutrophication levels of tidal basins in the Wadden Sea can be caused by external factors, like organic matter import, and internal factors like the morphology and hydrodynamics of the receiving tidal basin. For instance, benthic nutrients from remineralized organic matter may be more concentrated in shallow basins or diluted in basins with high exchange rates. In addition, the location of a monitoring station may determine which basin-specific water masses are actually observed. In the present paper a hydrodynamic intertidal imprint (IMP) is estimated for ten stations in various tidal basins of the Wadden Sea. The fraction of time water masses spent in intertidal areas prior to observation is calculated by linking the Lagrangian transport module PELETS to already existing hourly reconstructions of currents between 1959 and 2003. Irrespective of water depth, additional calculations of mean residence times (MRT) in the Wadden Sea indicate whether, in the case of low IMP values, water masses originate from coastal areas or tidal channels. Results show distinct regional differences, with highest values in the eastern part of the Dutch sector of the southern Wadden Sea (IMP=77%, MRT=99%) and lowest values in the German/Danish sector of the northern Wadden Sea (IMP=1.1%, MRT=21%). The IMP correlates positively with observed nutrient levels (R2=0.83). Evidently, this residence time-based intertidal signal is pivotal in explaining regional variations in eutrophication levels revealed by long-term comparative data from different monitoring stations.

  14. Social behavior in a genetic model of dopamine dysfunction at different neurodevelopmental time points.

    Science.gov (United States)

    Kabitzke, P A; Simpson, E H; Kandel, E R; Balsam, P D

    2015-09-01

    Impairments in social behavior characterize many neurodevelopmental psychiatric disorders. In fact, the temporal emergence and trajectory of these deficits can define the disorder, specify their treatment and signal their prognosis. The sophistication of mouse models with neurobiological endophenotypes of many aspects of psychiatric diseases has increased in recent years, with the necessity to evaluate social behavior in these models. We adapted an assay for the multimodal characterization of social behavior at different development time points (juvenile, adolescent and adult) in control mice in different social contexts (specifically, different sex pairings). Although social context did not affect social behavior in juvenile mice, it did have an effect on the quantity and type of social interaction as well as ultrasonic vocalizations in both adolescence and adulthood. We compared social development in control mice to a transgenic mouse model of the increase in postsynaptic striatal D2R activity observed in patients with schizophrenia (D2R-OE mice). Genotypic differences in social interactions emerged in adolescence and appeared to become more pronounced in adulthood. That vocalizations emitted from dyads with a D2R-OE subject were negatively correlated with active social behavior while vocalizations from control dyads were positively correlated with both active and passive social behavior also suggest social deficits. These data show that striatal dopamine dysfunction plays an important role in the development of social behavior and mouse models such as the one studied here provide an opportunity for screening potential therapeutics at different developmental time points. © 2015 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  15. The time-lapse AVO difference inversion for changes in reservoir parameters

    Science.gov (United States)

    Longxiao, Zhi; Hanming, Gu; Yan, Li

    2016-12-01

    The result of conventional time-lapse seismic processing is the difference between the amplitude and the post-stack seismic data. Although stack processing can improve the signal-to-noise ratio (SNR) of seismic data, it also causes a considerable loss of important information about the amplitude changes and only gives the qualitative interpretation. To predict the changes in reservoir fluid more precisely and accurately, we also need the quantitative information of the reservoir. To achieve this aim, we develop the method of time-lapse AVO (amplitude versus offset) difference inversion. For the inversion of reservoir changes in elastic parameters, we apply the Gardner equation as the constraint and convert the three-parameter inversion of elastic parameter changes into a two-parameter inversion to make the inversion more stable. For the inversion of variations in the reservoir parameters, we infer the relation between the difference of the reflection coefficient and variations in the reservoir parameters, and then invert reservoir parameter changes directly. The results of the theoretical modeling computation and practical application show that our method can estimate the relative variations in reservoir density, P-wave and S-wave velocity, calculate reservoir changes in water saturation and effective pressure accurately, and then provide reference for the rational exploitation of the reservoir.

  16. Keystroke dynamics and timing: accuracy, precision and difference between hands in pianist's performance.

    Science.gov (United States)

    Minetti, Alberto E; Ardigò, Luca P; McKee, Tom

    2007-01-01

    A commercially available acoustic grand piano, originally provided with keystroke speed sensors, is proposed as a standard instrument to quantitatively assess the technical side of pianist's performance, after the mechanical characteristics of the keyboard have been measured. We found a positional dependence of the relationship between the applied force and the resulting downstroke speed (i.e. treble keys descend fastest) due to the different hammer/hammer shaft mass to be accelerated. When this effect was removed by a custom software, the ability of 14 pianists was analysed in terms of variability in stroke intervals and keystroke speeds. C-major scales played by separate hands at different imposed tempos and at 5 subjectively chosen graded force levels were analysed to get insights into the achieved neuromuscular control. Accuracy and precision of time intervals and descent velocity of keystrokes were obtained by processing the generated MIDI files. The results quantitatively show: the difference between hands, the trade off between force range and tempo, and between time interval precision and tempo, the lower precision of descent speed associated to 'soft' playing, etc. Those results reflect well-established physiological and motor control characteristics of our movement system. Apart from revealing fundamental aspects of pianism, the proposed method could be used as a standard tool also for ergonomic (e.g. the mechanical work and power of playing), didactic and rehabilitation monitoring of pianists.

  17. CONTROL OF DICHELOPS MELACANTHUS WITH INSECTICIDES ASSOCIATED WITH SULPHUR APPLIED IN DIFFERENT TIMES IN CORN

    Directory of Open Access Journals (Sweden)

    J. C. Guerreiro

    2017-02-01

    Full Text Available The stink bug Dichelops melacanthus has become an important pest for corn crop and it has been causing several losses even in the initial phase of the crop. The objective of the experiment was the evaluation of effectiveness of the insecticides on the control of D. melacanthus in corn by adding of sulfur or not, in different control times. In order to evaluate the effect of the insecticide by adding or not sulfur on the control of D. melacanthus, 17 treatments with 4 different insecticides (with and without sulfur, in two different control times plus control were used to get the results. The experimental design used was the randomized blocks, with four repetitions. The evaluation of effectiveness on stink bugs control was gotten by visual evaluation of the symptoms at 6, 13 and 20 days after emergence (DAE. Analysis of variance by F test (Anova was done and the averages compared through Scott-knott test (p≤0,05. The pulverization of insecticides was more effective when it was done 4 (DAE, reducing the symptoms and injuries occasioned by the stink bug D. melacanthus and the mortality of damaged plants. The insecticide bifentrina+carbosulfano showed the higher effectiveness on stink bug control. To conclude, the use of sulfur associated to insecticides did not present a significant effect.

  18. A Characteristic Difference Scheme for Time-Fractional Heat Equations Based on the Crank-Nicholson Difference Schemes

    Directory of Open Access Journals (Sweden)

    Ibrahim Karatay

    2012-01-01

    Full Text Available We consider the numerical solution of a time-fractional heat equation, which is obtained from the standard diffusion equation by replacing the first-order time derivative with Riemann-Liouville fractional derivative of order α, where . The main purpose of this work is to extend the idea on Crank-Nicholson method to the time-fractional heat equations. We prove that the proposed method is unconditionally stable, and the numerical solution converges to the exact one with the order . Numerical experiments are carried out to support the theoretical claims.

  19. Moult Strategies Affect Age Differences in Autumn Migration Timing in East Mediterranean Migratory Passerines

    Science.gov (United States)

    Kiat, Yosef; Izhaki, Ido

    2016-01-01

    Adult passerines renew their flight feathers at least once every year. This complete moult occurs either in the breeding areas, just after breeding (summer moult), or, in some long-distance migratory species, at the non-breeding areas, after arrival to the southern wintering area at the end of autumn migration (winter moult). The aim of this study was to relate moult strategies with the DMD, the difference in median migration date, through Israel, between juveniles and adults. Our data on autumn migration timing in juveniles and adults was based on ringing data of 49,125 individuals belonging to 23 passerine species that breed in Europe and Western Asia and migrate through Israel. We found that DMD was associated with moult timing. In all species that perform a winter moult, adults preceded juveniles during autumn. Among migrants who perform a summer moult, we found evidence of both migration timing patterns: juveniles preceding adults or adults preceding juveniles. In addition, in summer moulters, we found a significant, positive correlation between mean breeding latitude and DMD. Although previous studies described that moult duration and extent can be affected by migration, we suggest that moult strategies affect both migration timing and migration strategy. These two moult strategies (summer or winter moult) also represent two unique migration strategies. Our findings highlight the evolutionary interplay between moult and migration strategies. PMID:26797292

  20. Distribution of residence times as a marker to distinguish different pathways for quantum transport

    Science.gov (United States)

    Rudge, Samuel L.; Kosov, Daniel S.

    2016-10-01

    Electron transport through a nanoscale system is an inherently stochastic quantum mechanical process. Electric current is a time series of electron tunneling events separated by random intervals. Thermal and quantum noise are two sources of this randomness. In this paper we use the quantum master equation to consider the following questions. (i) Given that an electron has tunneled into the electronically unoccupied system from the source electrode at some particular time, how long is it until an electron tunnels out to the drain electrode to leave the system electronically unoccupied, where there are no intermediate tunneling events (the tunneling path)? (ii) Given that an electron tunneled into the unoccupied system from the source electrode at some particular time, how long is it until an electron tunnels out to the drain electrode to leave the system electronically unoccupied, where there are no intermediate tunneling events (a tunneling path)? (iii) What are the distributions of these times? We show that electron correlations suppress the difference between the electron tunneling path and an electron tunneling path.

  1. Volatile compound profile of sous-vide cooked lamb loins at different temperature-time combinations.

    Science.gov (United States)

    Roldán, Mar; Ruiz, Jorge; Del Pulgar, José Sánchez; Pérez-Palacios, Trinidad; Antequera, Teresa

    2015-02-01

    Lamb loins were subjected to sous-vide cooking at different combinations of temperature (60 and 80°C) and time (6 and 24h) to assess the effect on the volatile compound profile. Major chemical families in cooked samples were aliphatic hydrocarbons and aldehydes. The volatile compound profile in sous-vide cooked lamb loin was affected by the cooking temperature and time. Volatile compounds arising from lipid oxidation presented a high abundance in samples cooked at low or moderate cooking conditions (60°C for 6 and 24h, 80°C for 6h), while a more intense time and temperature combination (80°C for 24h) resulted on a higher concentration of volatile compounds arising from Strecker degradations of amino acids, as 2-methylpropanal and 3-methylbutanal. Therefore, sous-vide cooking at moderately high temperatures for long times would result in the formation of a stronger meaty flavor and roast notes in lamb meat. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Finite difference time domain modeling of steady state scattering from jet engines with moving turbine blades

    Science.gov (United States)

    Ryan, Deirdre A.; Langdon, H. Scott; Beggs, John H.; Steich, David J.; Luebbers, Raymond J.; Kunz, Karl S.

    1992-01-01

    The approach chosen to model steady state scattering from jet engines with moving turbine blades is based upon the Finite Difference Time Domain (FDTD) method. The FDTD method is a numerical electromagnetic program based upon the direct solution in the time domain of Maxwell's time dependent curl equations throughout a volume. One of the strengths of this method is the ability to model objects with complicated shape and/or material composition. General time domain functions may be used as source excitations. For example, a plane wave excitation may be specified as a pulse containing many frequencies and at any incidence angle to the scatterer. A best fit to the scatterer is accomplished using cubical cells in the standard cartesian implementation of the FDTD method. The material composition of the scatterer is determined by specifying its electrical properties at each cell on the scatterer. Thus, the FDTD method is a suitable choice for problems with complex geometries evaluated at multiple frequencies. It is assumed that the reader is familiar with the FDTD method.

  3. Divorcing Mothers’ Use of Protective Strategies: Differences Over Time and by Violence Experience

    Science.gov (United States)

    Haselschwerdt, Megan L.; Mitchell, Elissa Thomann; Raffaelli, Marcela; Hardesty, Jennifer L.

    2015-01-01

    Objective The current study considered protective strategy use at various points in time for divorcing mothers with a range of marital violence experiences (including no history of violence and different types of violence). Method Divorcing mothers (N = 170) from one Midwestern county participated in two in-person interviews that included structured assessments of intimate partner violence (IPV) during the last year of marriage and use of protective strategies at three time points – last year of marriage and at separation (both assessed at Time 1) and since the first interview (at a three month follow-up). Results Divorcing mothers, regardless of marital violence experience, used an array of private and public protective strategies during the last year of marriage, at separation, and at the three-month follow up interview. In general, mothers who experienced coercive controlling violence reported using more protective strategies than mothers who experienced situational couple violence or no violence. Strategy use peaked at separation with an increase in public strategy use. Conclusions All divorcing mothers use a range of active coping strategies over time, yet findings emphasize the importance of making distinctions between types of IPV so that divorcing mothers receive individualized resources and support that best meet their needs and minimize potentials risks and losses as they navigate the divorce process. PMID:26858851

  4. Fixation of competing strategies when interacting agents differ in the time scale of strategy updating

    Science.gov (United States)

    Zhang, Jianlei; Weissing, Franz J.; Cao, Ming

    2016-09-01

    A commonly used assumption in evolutionary game theory is that natural selection acts on individuals in the same time scale; e.g., players use the same frequency to update their strategies. Variation in learning rates within populations suggests that evolutionary game theory may not necessarily be restricted to uniform time scales associated with the game interaction and strategy adaption evolution. In this study, we remove this restricting assumption by dividing the population into fast and slow groups according to the players' strategy updating frequencies and investigate how different strategy compositions of one group influence the evolutionary outcome of the other's fixation probabilities of strategies within its own group. Analytical analysis and numerical calculations are performed to study the evolutionary dynamics of strategies in typical classes of two-player games (prisoner's dilemma game, snowdrift game, and stag-hunt game). The introduction of the heterogeneity in strategy-update time scales leads to substantial changes in the evolution dynamics of strategies. We provide an approximation formula for the fixation probability of mutant types in finite populations and study the outcome of strategy evolution under the weak selection. We find that although heterogeneity in time scales makes the collective evolutionary dynamics more complicated, the possible long-run evolutionary outcome can be effectively predicted under technical assumptions when knowing the population composition and payoff parameters.

  5. Assessment of the methods for determining net radiation at different time-scales of meteorological variables

    Directory of Open Access Journals (Sweden)

    Ni An

    2017-04-01

    Full Text Available When modeling the soil/atmosphere interaction, it is of paramount importance to determine the net radiation flux. There are two common calculation methods for this purpose. Method 1 relies on use of air temperature, while Method 2 relies on use of both air and soil temperatures. Nowadays, there has been no consensus on the application of these two methods. In this study, the half-hourly data of solar radiation recorded at an experimental embankment are used to calculate the net radiation and long-wave radiation at different time-scales (half-hourly, hourly, and daily using the two methods. The results show that, compared with Method 2 which has been widely adopted in agronomical, geotechnical and geo-environmental applications, Method 1 is more feasible for its simplicity and accuracy at shorter time-scale. Moreover, in case of longer time-scale, daily for instance, less variations of net radiation and long-wave radiation are obtained, suggesting that no detailed soil temperature variations can be obtained. In other words, shorter time-scales are preferred in determining net radiation flux.

  6. Comparison of SAR calculation algorithms for the finite-difference time-domain method.

    Science.gov (United States)

    Laakso, Ilkka; Uusitupa, Tero; Ilvonen, Sami

    2010-08-07

    Finite-difference time-domain (FDTD) simulations of specific-absorption rate (SAR) have several uncertainty factors. For example, significantly varying SAR values may result from the use of different algorithms for determining the SAR from the FDTD electric field. The objective of this paper is to rigorously study the divergence of SAR values due to different SAR calculation algorithms and to examine if some SAR calculation algorithm should be preferred over others. For this purpose, numerical FDTD results are compared to analytical solutions in a one-dimensional layered model and a three-dimensional spherical object. Additionally, the implications of SAR calculation algorithms for dosimetry of anatomically realistic whole-body models are studied. The results show that the trapezium algorithm-based on the trapezium integration rule-is always conservative compared to the analytic solution, making it a good choice for worst-case exposure assessment. In contrast, the mid-ordinate algorithm-named after the mid-ordinate integration rule-usually underestimates the analytic SAR. The linear algorithm-which is approximately a weighted average of the two-seems to be the most accurate choice overall, typically giving the best fit with the shape of the analytic SAR distribution. For anatomically realistic models, the whole-body SAR difference between different algorithms is relatively independent of the used body model, incident direction and polarization of the plane wave. The main factors affecting the difference are cell size and frequency. The choice of the SAR calculation algorithm is an important simulation parameter in high-frequency FDTD SAR calculations, and it should be explained to allow intercomparison of the results between different studies.

  7. Individual differences in components of reaction time distributions and their relations to working memory and intelligence.

    Science.gov (United States)

    Schmiedek, Florian; Oberauer, Klaus; Wilhelm, Oliver; Süss, Heinz-Martin; Wittmann, Werner W

    2007-08-01

    The authors bring together approaches from cognitive and individual differences psychology to model characteristics of reaction time distributions beyond measures of central tendency. Ex-Gaussian distributions and a diffusion model approach are used to describe individuals' reaction time data. The authors identified common latent factors for each of the 3 ex-Gaussian parameters and for 3 parameters central to the diffusion model using structural equation modeling for a battery of choice reaction tasks. These factors had differential relations to criterion constructs. Parameters reflecting the tail of the distribution (i.e., tau in the ex-Gaussian and drift rate in the diffusion model) were the strongest unique predictors of working memory, reasoning, and psychometric speed. Theories of controlled attention and binding are discussed as potential theoretical explanations.

  8. Wind speed forecasting at different time scales: a non parametric approach

    CERN Document Server

    D'Amico, Guglielmo; Prattico, Flavio

    2013-01-01

    The prediction of wind speed is one of the most important aspects when dealing with renewable energy. In this paper we show a new nonparametric model, based on semi-Markov chains, to predict wind speed. Particularly we use an indexed semi-Markov model, that reproduces accurately the statistical behavior of wind speed, to forecast wind speed one step ahead for different time scales and for very long time horizon maintaining the goodness of prediction. In order to check the main features of the model we show, as indicator of goodness, the root mean square error between real data and predicted ones and we compare our forecasting results with those of a persistence model.

  9. Phosphoproteomics analysis of postmortem porcine muscle with pH decline rate and time difference

    DEFF Research Database (Denmark)

    Huang, Honggang; Larsen, Martin R; Karlsson, Anders H

    2012-01-01

    The aim of this study was to characterize the protein phosphorylation in postmortem (PM) muscle and reveal the change during meat quality development. The gel-based phosphoproteomic analysis of PM porcine muscle was performed in three pig groups with different pH decline rates from PM 1h to 24 h...... the reverse case. The phosphorylation level of 12 bands in sarcoplasmic fraction and 3 bands in myofibrillar fraction were significantly affected by the synergy effects of pH and time (pproteins were identified. The phosphorylation patterns of pyruvate kinase, triosephosphate isomerase-1......, tropomyosin and myosin regulatory light chain 2 showed to be related to PM muscle pH decline rate and time. Our work sheds light on the potential role of protein phosphorylation on regulation of meat quality development....

  10. Trait differences between naturalized and invasive plant species independent of residence time and phylogeny.

    Science.gov (United States)

    Gallagher, R V; Randall, R P; Leishman, M R

    2015-04-01

    The ability to predict which alien plants will transition from naturalized to invasive prior to their introduction to novel regions is a key goal for conservation and has the potential to increase the efficacy of weed risk assessment (WRA). However, multiple factors contribute to plant invasion success (e.g., functional traits, range characteristics, residence time, phylogeny), and they all must be taken into account simultaneously in order to identify meaningful correlates of invasion success. We compiled 146 pairs of phylogenetically paired (congeneric) naturalized and invasive plant species in Australia with similar minimum residence times (i.e., time since introduction in years). These pairs were used to test for differences in 5 functional traits (flowering duration, leaf size, maximum height, specific leaf area [SLA], seed mass) and 3 characteristics of species' native ranges (biome occupancy, mean annual temperature, and rainfall breadth) between naturalized and invasive species. Invasive species, on average, had larger SLA, longer flowering periods, and were taller than their congeneric naturalized relatives. Invaders also exhibited greater tolerance for different environmental conditions in the native range, where they occupied more biomes and a wider breadth of rainfall and temperature conditions than naturalized congeners. However, neither seed mass nor leaf size differed between pairs of naturalized and invasive species. A key finding was the role of SLA in distinguishing between naturalized and invasive pairs. Species with high SLA values were typically associated with faster growth rates, more rapid turnover of leaf material, and shorter lifespans than those species with low SLA. This suite of characteristics may contribute to the ability of a species to transition from naturalized to invasive across a wide range of environmental contexts and disturbance regimes. Our findings will help in the refinement of WRA protocols, and we advocate the inclusion

  11. The time aspect of bioenergy. Climate impacts of bioenergy due to differences in carbon uptake rates

    Energy Technology Data Exchange (ETDEWEB)

    Zetterberg, Lars [IVL Swedish Environmental Research Institute, Stockholm (Sweden); Chen, Deliang [Dept. of Earth Sciences, Univ. of Gothenburg, Gothenburg (Sweden)

    2011-07-01

    This paper investigates the climate impacts from bioenergy due to how they influence carbon stocks over time and more specifically how fast combustion related carbon emissions are compensated by uptake of atmospheric carbon. A set of fuel types representing different uptake rates are investigated, namely willow, branches and tops, stumps and coal. Net emissions are defined as emissions from utilizing the fuel minus emissions from a reference case of no utilisation. In the case of forest residues, the compensating 'uptake' is avoided emissions from the reference case of leaving the residues to decompose on the ground. Climate impacts are estimated using the measures radiative forcing and global average surface temperature, which have been calculated by an energy balance climate model. We conclude that there is a climate impact from using bioenergy due to how fast the emission pulse is compensated by uptake of atmospheric carbon (or avoided emissions). Biofuels with slower uptake rates have a stronger climate impact than fuels with a faster uptake rate, assuming all other parameters equal. The time perspective over which the analysis is done is crucial for the climate impact of biofuels. If only biogenic fluxes are considered, our results show that over a 100 year perspective branches and tops are better for climate mitigation than stumps which in turn are better than coal. Over a 20 year time perspective this conclusion holds, but the differences between these fuels are relatively smaller. Establishing willow on earlier crop land may reduce atmospheric carbon, provided new land is available. However, these results are inconclusive since we haven't considered the effects, if needed, of producing the traditional agricultural crops elsewhere. The analysis is not a life cycle assessment of different fuels and does therefore not consider the use of fossil fuels for logging, transportation and refining, other greenhouse gases than carbon or energy

  12. KEY FACTORS AND TIMING PATTERNS IN THE TENNIS FOREHAND OF DIFFERENT SKILL LEVELS

    Directory of Open Access Journals (Sweden)

    Johannes Landlinger

    2010-12-01

    Full Text Available The main purpose of the present study was to quantify and compare selected kinematic variables and their timing during the tennis forehand of different skill levels. An eight-camera 400 Hz, Vicon motion analysis system recorded kinematic data of six ATP- professionals (elite and seven high performance (HP players when shots were played cross court and down the line. Timing of the maximum angles, linear and angular velocities was measured prior to and after impact. A total of twelve strokes per subject were analyzed from the beginning to the end of horizontal racquet movement. Significant differences (p < 0.01 and large effect sizes were observed between elite and HP players in the timing of maximum pelvis (-0.075 ± 0.008 vs. -0.093 ± 0.012 s and trunk angular velocities (-0.057 ± 0.004 vs. -0.075 ± 0.011 s before impact. The elite group showed a tendency (p < 0.05 towards higher peak horizontal shoulder (3.0 ± 0.4 vs. 2.5 ± 0.4 m·s-1 and racquet velocities (33.1 ± 2.4 vs. 31.1 ± 1.9 m·s-1 compared to the HP players. Depending on the situation (cross court vs. down the line, different peak hip, racquet and separation angles were found for both groups. Similar peak values were detected between groups for maximum angular velocities and displacement of key variables that had been selected for analysis. The findings of this study can be vital for successful player development, improved performance or injury prevention. The later occurrence of maximum angular pelvis and trunk rotations were the main reasons for the tendency towards higher horizontal shoulder and racquet velocities in the elite group.

  13. Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities

    Directory of Open Access Journals (Sweden)

    A.E. Lima-Silva

    2009-05-01

    Full Text Available This study examined the effects of pre-exercise carbohydrate availability on the time to exhaustion for moderate and heavy exercise. Seven men participated in a randomized order in two diet and exercise regimens each lasting 3 days with a 1-week interval for washout. The tests were performed at 50% of the difference between the first (LT1 and second (LT2 lactate breakpoint for moderate exercise (below LT2 and at 25% of the difference between the maximal load and LT2 for heavy exercise (above LT2 until exhaustion. Forty-eight hours before each experimental session, subjects performed a 90-min cycling exercise followed by 5-min rest periods and a subsequent 1-min cycling bout at 125% VO2max/1-min rest periods until exhaustion to deplete muscle glycogen. A diet providing 10% (CHOlow or 65% (CHOmod energy as carbohydrates was consumed for 2 days until the day of the experimental test. In the exercise below LT2, time to exhaustion did not differ between the CHOmod and the CHOlow diets (57.22 ± 24.24 vs 57.16 ± 25.24 min. In the exercise above LT2, time to exhaustion decreased significantly from 23.16 ± 8.76 min on the CHOmod diet to 18.30 ± 5.86 min on the CHOlow diet (P < 0.05. The rate of carbohydrate oxidation, respiratory exchange ratio and blood lactate concentration were reduced for CHOlow only during exercise above LT2. These results suggest that muscle glycogen depletion followed by a period of a low carbohydrate diet impairs high-intensity exercise performance.

  14. How does landscape structure influence catchment transit time across different geomorphic provinces?

    Science.gov (United States)

    Tetzlaff, D.; Seibert, J.; McGuire, K.J.; Laudon, H.; Burns, Douglas A.; Dunn, S.M.; Soulsby, C.

    2009-01-01

    Despite an increasing number of empirical investigations of catchment transit times (TTs), virtually all are based on individual catchments and there are few attempts to synthesize understanding across different geographical regions. Uniquely, this paper examines data from 55 catchments in five geomorphic provinces in northern temperate regions (Scotland, United States of America and Sweden). The objective is to understand how the role of catchment topography as a control on the TTs differs in contrasting geographical settings. Catchment inverse transit time proxies (ITTPs) were inferred by a simple metric of isotopic tracer damping, using the ratio of standard deviation of ??18O in streamwater to the standard deviation of ??18O in precipitation. Quantitative landscape analysis was undertaken to characterize the catchments according to hydrologically relevant topographic indices that could be readily determined from a digital terrain model (DTM). The nature of topographic controls on transit times varied markedly in different geomorphic regions. In steeper montane regions, there are stronger gravitational influences on hydraulic gradients and TTs tend to be lower in the steepest catchments. In provinces where terrain is more subdued, direct topographic control weakened; in particular, where flatter areas with less permeable soils give rise to overland flow and lower TTs. The steeper slopes within this flatter terrain appear to have a greater coverage of freely draining soils, which increase sub-surface flow, therefore increasing TTs. Quantitative landscape analysis proved a useful tool for intercatchment comparison. However, the critical influence of sub-surface permeability and connectivity may limit the transferability of predictive tools of hydrological function based on topographic parameters alone. Copyright ?? 2009 John Wiley & Sons, Ltd.

  15. Single-stage laparoscopic management of acute gallstone pancreatitis: outcomes at different timings.

    Science.gov (United States)

    Navarro-Sanchez, Antonio; Ashrafian, Hutan; Laliotis, Aggelos; Qurashi, Kamran; Martinez-Isla, Alberto

    2016-06-01

    Definitive therapy for gallstone pancreatitis requires eradication of gallstones with cholecystectomy and common bile duct (CBD) clearance. Current guidelines recommend this be done within the same admission and preferably by laparoscopic cholecystectomy and CBD exploration. We report our experience of laparoscopic single-stage management with cholecystectomy and intraoperative cholangiogram followed by laparoscopic bile duct exploration (LBDE) when necessary performed at three different stages. From January 1998 to December 2012, 134 patients (100 females and 34 males) underwent single-stage laparoscopic management of gallstone pancreatitis. Patients were classified according to the timing of surgery: "A", ≤7 days from symptom onset (n=27); "B", 8 to 30 days (n=58) and "C", >30 days (n=49). LBDE was performed in 30 patients with a success rate of 100%. CBD stones were found in 25 patients (A: 22.2%, B: 22.4%, C: 12.2%). CBD stones were more common in patients undergoing surgery within 30 days of presentation than after this time point (P=0.35). Multiple choledocholithiasis was more frequent in patients treated within 7 days (P=0.04). The 30-day mortality after surgery was 0, with no conversion to an open approach. Overall complication rate was 11.9%, which did not differ significantly between patients treated within 7 days or after this time point (P=0.83). This study demonstrated the feasibility and reproducibility of single-stage laparoscopic management of acute gallstone pancreatitis, which has a low complication rate at any stage. Patients undergoing early treatment have a higher incidence of choledocholithiasis and multiple stones than those treated after 30 days, supporting the passage of stones with time.

  16. [Differences between Dutch provinces in perinatal mortality and travel time to hospital].

    Science.gov (United States)

    Ravelli, Anita C J; Rijninks-van Driel, Greta C; Erwich, Jan Jaap H M; Mol, Ben Willem J; Brouwers, Hens A A; Abu Hanna, Ameen; Eskes, Martine

    2011-01-01

    To investigate differences in perinatal mortality between Dutch provinces and to determine the significance of risk factors including travel time from home to the hospital during labour. Cohort study. The study was based on 1,242,725 singleton births in 2000-2006 as recorded in the Netherlands Perinatal Registry. The influence of province on perinatal mortality was estimated, with logistic regression analysis adjusting for risk factors (age, parity, ethnicity, socioeconomic status) and care factors such as start of antenatal care and travel time. The perinatal mortality rate in the Netherlands was 9.9 per 1000 births. The provinces with the highest mortality rates were Friesland (11.3‰), Groningen (11.1‰), Zeeland (10.6‰) and Flevoland (10.4‰). Noord-Brabant (9.2‰) and Limburg (9.2‰) had the lowest mortality rates. These differences were significantly higher for Friesland (odds ratio: 1.16; 95%-CI: 1.05-1.28) and Groningen (odds ratio: 1.13; 95%-CI: 1.02-1.26). Starting late with perinatal care, at 18 weeks of gestation or later was an important risk factor (adjusted odds ratio 1.8; 95%-CI: 1.7-1.8). Low socio-economic status could partly be associated with the higher mortality risk in Groningen. Longer travel time (≥ 20 minutes) was an independent risk factor associated with perinatal mortality. On average 19% of the women travelled ≥ 20 minutes to the hospital. In the provinces Groningen, Friesland, Flevoland and Zeeland these percentages ranged between 32 and 36%. The adjusted odds ratio of travel time was 1.7 (95%-CI 1.6-1.7). The perinatal mortality differs per province. This can be explained by longer travel time to the hospital during labour. Late start of perinatal care and low socio-economic status also affect the mortality rate. These risk factors need to be taken into account during registration, investigation, audit and obstetric policy.

  17. New approximate solutions per unit of time for periodically checked systems with different lifetime distributions

    Directory of Open Access Journals (Sweden)

    J. Rodrigues Dias

    2006-11-01

    Full Text Available Systems with different lifetime distributions, associated with increasing, decreasing, constant, and bathtub-shaped hazard rates, are examined in this paper. It is assumed that a failure is only detected if systems are inspected. New approximate solutions for the inspection period and for the expected duration of hidden faults are presented, on the basis of the assumption that only periodic and perfect inspections are carried out. By minimizing total expected cost per unit of time, on the basis of numerical results and a range of comparisons, the conclusion is drawn that these new approximate solutions are extremely useful and simple to put into practice.

  18. Finite-difference time-domain analysis of light propagation in cholesteric liquid crystalline droplet array

    Science.gov (United States)

    Yamamoto, Kaho; Iwai, Yosuke; Uchida, Yoshiaki; Nishiyama, Norikazu

    2016-08-01

    We numerically analyzed the light propagation in cholesteric liquid crystalline (CLC) droplet array by the finite-difference time-domain (FDTD) method. The FDTD method successfully reproduced the experimental light path observed in the complicated photonic structure of the CLC droplet array more accurately than the analysis of CLC droplets by geometric optics with Bragg condition, and this method help us understand the polarization of the propagating light waves. The FDTD method holds great promise for the design of various photonic devices composed of curved photonic materials like CLC droplets and microcapsules.

  19. Scattering analysis of periodic structures using finite-difference time-domain

    CERN Document Server

    ElMahgoub, Khaled; Elsherbeni, Atef Z

    2012-01-01

    Periodic structures are of great importance in electromagnetics due to their wide range of applications such as frequency selective surfaces (FSS), electromagnetic band gap (EBG) structures, periodic absorbers, meta-materials, and many others. The aim of this book is to develop efficient computational algorithms to analyze the scattering properties of various electromagnetic periodic structures using the finite-difference time-domain periodic boundary condition (FDTD/PBC) method. A new FDTD/PBC-based algorithm is introduced to analyze general skewed grid periodic structures while another algor

  20. The Effect of Interchannel Time Difference on Localisation in Vertical Stereophony

    OpenAIRE

    Wallis, Rory; Lee, Hyunkook

    2015-01-01

    Listening tests were conducted in order to analyse the localisation of band-limited stimuli in vertical stereophony. The test stimuli were seven octave bands of pink noise, with centre frequencies ranging from 125–8000Hz, as well as broadband pink noise. Stimuli were presented from vertically arranged loudspeakers either monophonically or as vertical phantom images, created with the upper loudspeaker delayed with respect to the lower by 0, 0.5, 1, 5 and 10ms (i.e. interchannel time difference...

  1. Adaptive Synchronization between Two Different Complex Networks with Time-Varying Delay Coupling

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-Rui; JIAO Li-Cheng; WU Jian-She; WANG Xiao-Hua

    2009-01-01

    A new general network model for two complex networks with time-varying delay coupling is presented.Then we investigate its synchronization phenomena.The two complex networks of the model differ in dynamic nodes,the number of nodes and the coupling connections.By using adaptive controllers,a synchronization criterion is derived.Numerical examples are given to demonstrate the effectiveness of the obtained synchronization criterion.This study may widen the application range of synchronization,such as in chaotic secure communication.

  2. Cost, Time, and Risk Assessment of Different Wave Energy Converter Technology Development Trajectories: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Jochem W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Laird, Daniel [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Costello, Ronan [Wave Venture; Roberts, Jesse [Sandia National Laboratories; Bull, Diana [Sandia National Laboratories; Babarit, Aurelien [Ecole Centrale de Nantes; Nielsen, Kim [Ramboll; Ferreira, Claudio Bittencourt [DNV-GL; Kennedy, Ben [Wave Venture

    2017-09-14

    This paper presents a comparative assessment of three fundamentally different wave energy converter technology development trajectories. The three technology development trajectories are expressed and visualised as a function of technology readiness levels and technology performance levels. The assessment shows that development trajectories that initially prioritize technology readiness over technology performance are likely to require twice the development time, consume a threefold of the development cost, and are prone to a risk of technical or commercial failure of one order of magnitude higher than those development trajectories that initially prioritize technology performance over technology readiness.

  3. Design of Real-time Communication Adapter for Different Protocol Sensors in Sensor Web

    Directory of Open Access Journals (Sweden)

    Longlong Lu

    2012-09-01

    Full Text Available A real-time communication adapter named SensorAdapter is designed to communicate between different protocols sensors and data service layer in Sensor Web. The adapter is extended and restructured based on SensorBus, an open source project raised by a German company called 52north. By structuring the receiving module and extending the proxies of sensors according to the communication protocols the sensors use, the adapter can receive sensing information detected by different protocols sensors simultaneously. The receiving module identifies a sensor and finds its corresponding proxy in SensorAdapter by sensor ID (SensorID, and then packages the sensing information to XMPP messages and sends them to XMPPServer by invoking the methods in its proxy. At last, an example of SOS is achieved to verify the effect of the adapter.

  4. Impact of Different Electrical Time-Based Activations on NiTi Shape Memory Alloys

    Science.gov (United States)

    Fleczok, Benjamin; Rathmann, Christian; Otibar, Dennis; Weirich, Antonia; Kuhlenkötter, Bernd

    2017-06-01

    The use of NiTi shape-memory alloys (SMA) in actuators bears significant advantages for designing robust, simple and lightweight applications. The SMA effect is based on a phase transformation of the atomic lattice in response to stress, strain and temperature. The resulting crystallographic configurations lead to a complex behavior revealing different electrical and mechanical characteristics. In view of the impact of thermo-mechanical cyclization on the operational lifetime, this paper investigates the influences of different types of electrical activation. For this purpose, six current curves with six samples each are compared to a reference activation with regard to the operational lifetime. The chosen time of activation is 1 second in accordance with an industrially relevant cycle of technical actuators. Based on the results of these investigations, recommendations of the activation type shall be developed for the operational lifetime of NiTi-SMA.

  5. Comparison of different Kalman filter approaches in deriving time varying connectivity from EEG data.

    Science.gov (United States)

    Ghumare, Eshwar; Schrooten, Maarten; Vandenberghe, Rik; Dupont, Patrick

    2015-08-01

    Kalman filter approaches are widely applied to derive time varying effective connectivity from electroencephalographic (EEG) data. For multi-trial data, a classical Kalman filter (CKF) designed for the estimation of single trial data, can be implemented by trial-averaging the data or by averaging single trial estimates. A general linear Kalman filter (GLKF) provides an extension for multi-trial data. In this work, we studied the performance of the different Kalman filtering approaches for different values of signal-to-noise ratio (SNR), number of trials and number of EEG channels. We used a simulated model from which we calculated scalp recordings. From these recordings, we estimated cortical sources. Multivariate autoregressive model parameters and partial directed coherence was calculated for these estimated sources and compared with the ground-truth. The results showed an overall superior performance of GLKF except for low levels of SNR and number of trials.

  6. Separating timing, movement conditions and individual differences in the analysis of human movement

    DEFF Research Database (Denmark)

    Raket, Lars Lau; Grimme, Britta; Schöner, Gregor;

    2016-01-01

    mixed-effects models as viable alternatives to conventional analysis frameworks. The model is then combined with a novel factor-analysis model that estimates the low-dimensional subspace within which movements vary when the task demands vary. Our framework enables us to visualize different dimensions......A central task in the analysis of human movement behavior is to determine systematic patterns and differences across experimental conditions, participants and repetitions. This is possible because human movement is highly regular, being constrained by invariance principles. Movement timing...... of movement variation and to test hypotheses about the effect of obstacle placement and height on the movement path. We demonstrate that the approach can be used to uncover new properties of human movement....

  7. Diastolic time – frequency relation in the stress echo lab: filling timing and flow at different heart rates

    Directory of Open Access Journals (Sweden)

    Faita Francesco

    2008-04-01

    Full Text Available Abstract A cutaneous force-frequency relation recording system based on first heart sound amplitude vibrations has been recently validated. Second heart sound can be simultaneously recorded in order to quantify both systole and diastole duration. Aims 1- To assess the feasibility and extra-value of operator-independent, force sensor-based, diastolic time recording during stress. Methods We enrolled 161 patients referred for stress echocardiography (exercise 115, dipyridamole 40, pacing 6 patients. The sensor was fastened in the precordial region by a standard ECG electrode. The acceleration signal was converted into digital and recorded together with ECG signal. Both systolic and diastolic times were acquired continuously during stress and were displayed by plotting times vs. heart rate. Diastolic filling rate was calculated as echo-measured mitral filling volume/sensor-monitored diastolic time. Results Diastolic time decreased during stress more markedly than systolic time. At peak stress 62 of the 161 pts showed reversal of the systolic/diastolic ratio with the duration of systole longer than diastole. In the exercise group, at 100 bpm HR, systolic/diastolic time ratio was lower in the 17 controls (0.74 ± 0.12 than in patients (0.86 ± 0.10, p Diastolic filling rate increased from 101 ± 36 (rest to 219 ± 92 ml/m2* s-1 at peak stress (p Conclusion Cardiological systolic and diastolic duration can be monitored during stress by using an acceleration force sensor. Simultaneous calculation of stroke volume allows monitoring diastolic filling rate. Stress-induced "systolic-diastolic mismatch" can be easily quantified and is associated to several cardiac diseases, possibly expanding the spectrum of information obtainable during stress.

  8. REAL-TIME STABILITY AND PROFILE COMPARISON MEASUREMENTS BETWEEN TWO DIFFERENT LTPS.

    Energy Technology Data Exchange (ETDEWEB)

    QIAN, S.; WANG, D.J.

    2005-07-31

    The Long Trace Profiler (LTP) is a precise angle measurement instrument, with a sensitivity and accuracy that can be in the sub-micron radian range. LTP characteristics depend on the particular LTP system schematic design, and the quality of components and assembly. The conditions of temperature, alignment, and mirror support during the measurement process vary between different laboratories, which influences significantly the test repeatability and accuracy. In this paper we introduce a direct comparison method to test the same object at the same point in the same environment at the same time by using two LTPs, which significantly increases the reliability of the comparison. A compact, portable LTP (PTLTP), which can be carried to different laboratories around the world, is used for comparison testing. Stability Comparison experiments between the LTP II at the National Synchrotron Radiation Research Center (NSRRC), and the PTLTP of Brookhaven National Laboratory (BNL) reveal significant differences in performance between the instruments. The experiment is set up so that each optical head simultaneously records both its own sample probe beam and also the probe beam from the other optical head. The two probe beams are reflected from same point on the mirror. Tests show that the stability of the PTLTP with a monolithic beam splitter is 10 times better than the stability of the LTP II which has a separated beam splitter unit. A scheme for comparing scanning measurements of a mirror is introduced. Experimental results show a significant difference between the two LTPs due mainly to distortions in the optical components inside the optical head. A new scheme is proposed for further mirror comparison scanning tests.

  9. Effect of irradiation times on the polymerization depth of contemporary fissure sealants with different opacities

    Directory of Open Access Journals (Sweden)

    Boniek Castillo Dutra Borges

    2011-04-01

    Full Text Available The aim of this study was to evaluate the depth of curing of 10 contemporary blue light-activated dental flowable materials at several opacities, influenced by different irradiation times using FT-IR spectroscopy. Fifty-five specimens (n = 5 with a 5-mm diameter and 1-mm thickness of translucent (Opallis Flow T, yellowed (Master Flow A2; Opallis Flow A2; Natural Flow A2; Fluroshield Yellowed, and opaque materials (Master Flow OA2; Natural Flow O; Opallis Flow OA3.5; Opallis Flow OP; Fluroshield White were obtained at six curing times (10s, 20s, 30s, 40s, 50s, and 60s using a high-intensity LED (Coltolux, Coltène/Whaledent. The degree of conversion (DC (% was obtained using the Nexus 470 FTIR Spectrometer (Nicolet Instruments, USA. The FTIR-ATR spectra for uncured and cured samples were analyzed using a ZnSe crystal. The top and bottom surfaces of the cured specimens were analyzed to obtain the depth of curing. Two-way ANOVA was used to analyze the data. The highest curing depth was obtained by Natural Flow OA2, while the lowest was shown by Master Flow OA2. The shortest curing time generated similar depths of cure in comparison with the most extensive for Opallis Flow A2 and Fluroshield Yellowed. Therefore, depth of curing, influenced by the irradiation time, was dependent on the materials. Using the Natural Flow OA2 opaque sealant and the 10-s curing time for Opallis Flow A2 and Fluroshield Yellowed may represent alternative approaches to sealing tooth fissures.

  10. Different time concepts in the classroom. From monologue to dialogue: space

    Directory of Open Access Journals (Sweden)

    Leonor Sáez Méndez

    2012-12-01

    Full Text Available This paper explores, taking as its starting point cognitive variables, the essential function which affective variables have in the teaching of foreign languages. The conceptual transposition a reorientation required to acquire a second language involves distinguishing different philosophical concepts about space and time. From the 1970s and on, the linguistic requirements of teaching a language have taken a Kantian turn. Together with the principles of pragmatics and interculturality, it is important to work with concepts such as perception, disposition, motivation, intuition, level of empathy, and fear. Bearing in mind that these are complex factors which have a great impact on the process of immersion in a foreign language, it is worth asking if they are just temporal. The actual learning process, involving self-study, requires additional support to focus the learner’s resources and encourage them to immerse themselves in and identify with the culture associated with the language they are learning. These areas are in the critical period, especially in the post-Kantian critical, empirical thresholds that shape our thinking and guide the choice of exercises. Our study aims 1 to refl ect on the diff erent conceptions of time (as inner meaning, cognitive time underlying foreign language teaching; 2 to explore whether is it possible to develop a methodology based just on time, therefore leaving, space to one side or, in contrast, whether it is space which rules over time in the process of foreign language acquisition.

  11. Cross-cultural differences in mental representations of time: evidence from an implicit nonlinguistic task.

    Science.gov (United States)

    Fuhrman, Orly; Boroditsky, Lera

    2010-11-01

    Across cultures people construct spatial representations of time. However, the particular spatial layouts created to represent time may differ across cultures. This paper examines whether people automatically access and use culturally specific spatial representations when reasoning about time. In Experiment 1, we asked Hebrew and English speakers to arrange pictures depicting temporal sequences of natural events, and to point to the hypothesized location of events relative to a reference point. In both tasks, English speakers (who read left to right) arranged temporal sequences to progress from left to right, whereas Hebrew speakers (who read right to left) arranged them from right to left, replicating previous work. In Experiments 2 and 3, we asked the participants to make rapid temporal order judgments about pairs of pictures presented one after the other (i.e., to decide whether the second picture showed a conceptually earlier or later time-point of an event than the first picture). Participants made responses using two adjacent keyboard keys. English speakers were faster to make "earlier" judgments when the "earlier" response needed to be made with the left response key than with the right response key. Hebrew speakers showed exactly the reverse pattern. Asking participants to use a space-time mapping inconsistent with the one suggested by writing direction in their language created interference, suggesting that participants were automatically creating writing-direction consistent spatial representations in the course of their normal temporal reasoning. It appears that people automatically access culturally specific spatial representations when making temporal judgments even in nonlinguistic tasks. Copyright © 2010 Cognitive Science Society, Inc.

  12. Influence of Short-time Oxidation on Corrosion Properties of Directionally Solidified Superalloys with Different Orientations

    Directory of Open Access Journals (Sweden)

    MA Luo-ning

    2016-07-01

    Full Text Available In order to investigate the corrosion performance on intersecting and longitudinal surfaces of unoxidized and oxidized directionally solidified superalloys, Ni-base directionally solidified superalloy DZ125 and Co-base directionally solidified superalloy DZ40M were selected. Oxidation behavior on both alloys with different orientations was investigated at 1050℃ at different times, simulating the oxidation process of vanes or blades in service; subsequent electrochemical performance in 3.5%NaCl aqueous solution was studied on two orientations of unoxidized and oxidized alloys, simulating the corrosion process of superalloy during downtime. The results show that grain boundaries and sub-boundaries of directionally solidified superalloys are susceptible to corrosion and thus longitudinal surface with lower area fraction of grain boundaries has higher corrosion resistance. Compared to intersecting surface of alloys, the structure of grain boundaries of longitudinal surface is less conducive to diffusion and thus the oxidation rate on longitudinal surface is lower. Formation of oxide layers on alloys after short-time oxidation provides protective effect and enhances the corrosion resistance.

  13. Modelling of the acid base properties of two thermophilic bacteria at different growth times

    Science.gov (United States)

    Heinrich, Hannah T. M.; Bremer, Phil J.; McQuillan, A. James; Daughney, Christopher J.

    2008-09-01

    Acid-base titrations and electrophoretic mobility measurements were conducted on the thermophilic bacteria Anoxybacillus flavithermus and Geobacillus stearothermophilus at two different growth times corresponding to exponential and stationary/death phase. The data showed significant differences between the two investigated growth times for both bacterial species. In stationary/death phase samples, cells were disrupted and their buffering capacity was lower than that of exponential phase cells. For G. stearothermophilus the electrophoretic mobility profiles changed dramatically. Chemical equilibrium models were developed to simultaneously describe the data from the titrations and the electrophoretic mobility measurements. A simple approach was developed to determine confidence intervals for the overall variance between the model and the experimental data, in order to identify statistically significant changes in model fit and thereby select the simplest model that was able to adequately describe each data set. Exponential phase cells of the investigated thermophiles had a higher total site concentration than the average found for mesophilic bacteria (based on a previously published generalised model for the acid-base behaviour of mesophiles), whereas the opposite was true for cells in stationary/death phase. The results of this study indicate that growth phase is an important parameter that can affect ion binding by bacteria, that growth phase should be considered when developing or employing chemical models for bacteria-bearing systems.

  14. Alzheimer's Disease: Differences of Transdermal versus Oral Treatment on Caregiving Time

    Science.gov (United States)

    Riedel, O.; Emmrich, A.; Klotsche, J.; Dodel, R.; Förstl, H.; Maier, W.; Reichmann, H.; Wittchen, H.-U.

    2012-01-01

    Background Data on indirect effects of dementia treatment on caregiver burden obtained from naturalistic studies are still lacking. We explored differences between patients with oral and transdermal application of acetylcholine esterase inhibitors regarding caregiver's time burden and psychopathology. Methods A cross-sectional naturalistic cohort study of 403 patients in outpatient care with three treatment groups (none, oral, and transdermal) was conducted. Assessments included a standardized clinical burden questionnaire and a standardized caregiver interview. Results Any treatment was associated with lower burden in most measures. Transdermal treatment was superior regarding (1) administration time (p < 0.001); (2) rates of administration problems (p = 0.031); (3) burden in activities of daily living (p = 0.008), and (4) caregiver anxiety (OR 0.25; 95% CI 0.05–0.99). Caregivers did not report better quality of life regarding mental/physical health. Physicians’ and caregivers’ ratings of patients’ improvements were not associated (κ = 0.01–0.06). Conclusions Benefits associated with transdermal treatment do not translate into a better ‘generic quality of life’ of the caregiver. The substantially different perceptions of patients’ improvements need to be considered in future studies. PMID:23277781

  15. Effect of four different starting stances on sprint time in collegiate volleyball players.

    Science.gov (United States)

    Johnson, Trevor M; Brown, Lee E; Coburn, Jared W; Judelson, Daniel A; Khamoui, Andy V; Tran, Tai T; Uribe, Brandon P

    2010-10-01

    Starting stance plays an important role in influencing short-distance sprint speed and, therefore, the ability to reach a ball during sport play. The purpose of this study was to evaluate 4 different starting stances on sprint time. Twenty-six male and female collegiate volleyball players volunteered to participate in 1 testing session. Each subject performed 3 15-ft sprint trials at each of 4 different starting stances (P-parallel, FS-false step, S-staggered, and SFS-staggered false step) in random order. Analysis of variance revealed that there was no significant interaction of sex by stance, but there were main effects for sex (men were faster than women) and stance. The FS (1.18 ± 0.10 seconds), S (1.16 ± 0.07 seconds), and SFS (1.14 ± 0.06 seconds) stances were faster than the P (1.25 ± 0.09 seconds) stance, and the SFS stance was faster than the FS stance. This indicates that starting with a staggered stance (regardless of stepping back) produced the greatest sprinting velocity over the initial 15 feet. Although taking a staggered stance seems counterproductive, the resultant stretch-shortening cycle action and forward body lean likely increase force production of the push-off phase and place the total body center of mass ahead of the contacting foot, thereby, decreasing sprint time.

  16. Interdecadal Variations of Phase Delays Between Two Ni(n)o Indices at Different Time Scales

    Institute of Scientific and Technical Information of China (English)

    BIAN Jianchun; YANG Peicai

    2005-01-01

    Phase delays between two Nino indices-sea surface temperatures in Nino regions 1+2 and 3.4(1950-2001)-at different time scales are detected by wavelet analysis. Analysis results show that thereare two types of period bifurcations in the Nino indices and that period bifurcation points exist only in the region where the wavelet power is small. Interdecadal variation features of phase delays between the two indices vary with different time scales. In the periods of 40-72 months, the phase delay changes its sign in 1977: Nino 1+2 indices are 2-4 months earlier than Nino 3.4 indices before 1977, but 3-6 months later afterwards. In the periods of 20-40 months, however, the phase delay changes its sign in another way:Nino 1+2 indices are 1-4 months earlier before 1980 and during 1986-90, but 1-4 months later during 1980-83 and 1993-2001.

  17. Dental enamel roughness with different acid etching times: Atomic force microscopy study

    Directory of Open Access Journals (Sweden)

    Bruno Bochnia Cerci

    2012-01-01

    Full Text Available Objective: An important characteristic of human dental enamel not yet studied in detail is its surface roughness in mesoscopic scale. This study evaluated quantitatively and qualitatively the surface topography of acid etched enamel with different etching times. Materials and Methods: Ninety-six human maxillary bicuspids were randomly distributed into three groups (n=32: T0 (control, pumiced; T15, 35% phosphoric acid etched enamel for 15 s; T30, 35% phosphoric acid etched enamel for 30 s. Roughness measurements Ra, Rz and root mean square (RMS and 3D images of enamel′s topography were obtained with atomic force microscopy (AFM, which is a powerful technique to obtain direct measurements on microscale features. Results and Conclusions: Roughness variables Ra, Rz and RMS presented statistically significant differences to all groups (P<0.000, with values increasing with etching time. This increase was greater from T0 to T15 than from T15 to T30. Enamel surface alterations T15 to T30 occur mainly due to increase in height and deepening of prisms central region.

  18. Personal Best Time, Percent Body Fat, and Training Are Differently Associated with Race Time for Male and Female Ironman Triathletes

    Science.gov (United States)

    Knechtle, Beat; Wirth, Andrea; Baumann, Barbara; Knechtle, Patrizia; Rosemann, Thomas

    2010-01-01

    We studied male and female nonprofessional Ironman triathletes to determine whether percent body fat, training, and/or previous race experience were associated with race performance. We used simple linear regression analysis, with total race time as the dependent variable, to investigate the relationship among athletes' percent body fat, average…

  19. Physical Activity and Sedentary Screen Time in Obese and Overweight Children Living in Different Environments.

    Science.gov (United States)

    Raistenskis, Juozas; Sidlauskiene, Aurelija; Cerkauskiene, Rimante; Burokiene, Sigita; Strukcinskiene, Birute; Buckus, Raimondas

    2015-11-01

    To assess the relationship of children's physical activity and sedentary screen time with overweight and obesity in children living in different environments (town and city) in Lithuania. An analysis of anthropometric data from 532 children living in town and city areas was performed. A youth physical activity questionnaire (YPAQ) was conducted to evaluate physical activity and sedentary screen time. The prevalence of overweight and obesity among the children was 25.5% in the town and 18.6% in the city. Children living in the town on average engaged 9.3 min/day less in moderate to vigorous physical activity (p=0.050) and had 33.2 MET-min/day lower energy expenditure than children living in the city. Sedentary screen time was extremely high on weekends in both town and city children. A higher prevalence of overweight and obesity and a lower amount of moderate-to-vigorous physical activity was found in children living in the town compared to children living in the city. Copyright© by the National Institute of Public Health, Prague 2015.

  20. Impact of Donor Age, Gender and Handling Time on the DNA Concentration Left on Different Surfaces

    Directory of Open Access Journals (Sweden)

    Branka Gršković

    2014-09-01

    Full Text Available Background: We analyzed the correlation between several factors (donor age and gender, and handling time and trace DNA concentration that participants left on different surfaces (paper, plastic, plastic coated metal while holding items in their hands or rubbing them with their fingers, their palms, and the side of the palm of the dominant hand. Material and Methods: Sixty participants took part in the study. Items were swabbed with a moistened cotton swab. DNA was isolated using the Chelex procedure and quantified by real-time PCR. Results: We found that DNA concentration transferred to an item was independent of the handling time. On the contrary, it was dependent on the item’s texture; the greatest concentration was left on plastic coated metal (PCM and the least on paper. The greatest concentration of trace DNA was left by participants from 35 to 44 years of age. Results of the study showed that men deposit a higher DNA concentration than do women. Conclusion: Item texture, donor age, and gender influence trace DNA concentration. Further investigations are necessary to fully understand the process of DNA transfer from donors to handled items.

  1. Effect of lipstick on composite resin color at different application times

    Directory of Open Access Journals (Sweden)

    Avilmar Passos Galvão

    2010-12-01

    Full Text Available OBJECTIVES: The aim of this study was to evaluate the influence of the contact of two lipsticks, one with common fixer and one with ultra fixer, on the color of a composite resin immediately, 30 min and 24 h after photoactivation. MATERIAL AND METHODS: Ninety specimens were prepared with a composite resin, Filtek-Z350. Specimens were polished and divided into 9 groups (n=10 according to time elapsed after photoactivation (A- immediately; B- 30 min; C- 24 h and the contact with lipstick (UF- lipstick with ultra fixer; F- lipstick with common fixer. The control group was represented by specimens that did not have any contact with lipstick (C- without lipstick. Color measurements of the specimens were carried out using a spectrophotometer (Easyshade - CIE L* a* b* system. For UF and F groups, the baseline color of the specimens was measured immediately before pigmentation and the lipsticks were applied dry after 1 hour. The excess lipstick was removed with absorbent paper and final color checking was performed, including the control group. Differences between the final and baseline color measurements were calculated and data were analyzed statistically by the Kruskal-Wallis test at 5%. RESULTS: The means between the differences of color values were: AUF: 16.0; AF: 12.4; AC: 1.07; BUF: 9.51; BF: 8.3; BC: 0.91; CUF: 17.7; CF: 12.41; CC: 0.82. CONCLUSION: Groups where lipstick was applied showed greater staining than the control group at the three evaluation times. The lipstick with ultra fixer stained more than the lipstick with common fixer. Time elapsed between photoactivation and contact with lipstick had a similar influence on the groups that received lipstick application.

  2. Correlation Coefficients Between Different Methods of Expressing Bacterial Quantification Using Real Time PCR

    Directory of Open Access Journals (Sweden)

    Bahman Navidshad

    2012-02-01

    Full Text Available The applications of conventional culture-dependent assays to quantify bacteria populations are limited by their dependence on the inconsistent success of the different culture-steps involved. In addition, some bacteria can be pathogenic or a source of endotoxins and pose a health risk to the researchers. Bacterial quantification based on the real-time PCR method can overcome the above-mentioned problems. However, the quantification of bacteria using this approach is commonly expressed as absolute quantities even though the composition of samples (like those of digesta can vary widely; thus, the final results may be affected if the samples are not properly homogenized, especially when multiple samples are to be pooled together before DNA extraction. The objective of this study was to determine the correlation coefficients between four different methods of expressing the output data of real-time PCR-based bacterial quantification. The four methods were: (i the common absolute method expressed as the cell number of specific bacteria per gram of digesta; (ii the Livak and Schmittgen, ΔΔCt method; (iii the Pfaffl equation; and (iv a simple relative method based on the ratio of cell number of specific bacteria to the total bacterial cells. Because of the effect on total bacteria population in the results obtained using ΔCt-based methods (ΔΔCt and Pfaffl, these methods lack the acceptable consistency to be used as valid and reliable methods in real-time PCR-based bacterial quantification studies. On the other hand, because of the variable compositions of digesta samples, a simple ratio of cell number of specific bacteria to the corresponding total bacterial cells of the same sample can be a more accurate method to quantify the population.

  3. Effect of lipstick on composite resin color at different application times.

    Science.gov (United States)

    Galvão, Avilmar Passos; Jacques, Letícia Borges; Dantas, Luciana; Mathias, Paula; Mallmann, André

    2010-12-01

    The aim of this study was to evaluate the influence of the contact of two lipsticks, one with common fixer and one with ultra fixer, on the color of a composite resin immediately, 30 min and 24 h after photoactivation. Ninety specimens were prepared with a composite resin, Filtek-Z350. Specimens were polished and divided into 9 groups (n=10) according to time elapsed after photoactivation (A- immediately; B- 30 min; C- 24 h) and the contact with lipstick (UF- lipstick with ultra fixer; F- lipstick with common fixer). The control group was represented by specimens that did not have any contact with lipstick (C- without lipstick). Color measurements of the specimens were carried out using a spectrophotometer (Easyshade - CIE L* a* b* system). For UF and F groups, the baseline color of the specimens was measured immediately before pigmentation and the lipsticks were applied dry after 1 hour. The excess lipstick was removed with absorbent paper and final color checking was performed, including the control group. Differences between the final and baseline color measurements were calculated and data were analyzed statistically by the Kruskal-Wallis test at 5%. The means between the differences of color values were: AUF: 16.0; AF: 12.4; AC: 1.07; BUF: 9.51; BF: 8.3; BC: 0.91; CUF: 17.7; CF: 12.41; CC: 0.82. Groups where lipstick was applied showed greater staining than the control group at the three evaluation times. The lipstick with ultra fixer stained more than the lipstick with common fixer. Time elapsed between photoactivation and contact with lipstick had a similar influence on the groups that received lipstick application.

  4. Response of vegetation to different time-scales drought across China: Spatiotemporal patterns, causes and implications

    Science.gov (United States)

    Zhang, Qiang; Kong, Dongdong; Singh, Vijay P.; Shi, Peijun

    2017-05-01

    Based on Normalized Difference Vegetation Index (NDVI) and Standardized Precipitation Evapotranspiration Index (SPEI), we investigated vegetation response to different time-scales drought across different vegetation types and homogeneous clusters in China, by annual maximum Pearson correlation (Rmax) and the corresponding time-scales of drought. Results showed that: (1) 8 subregions with homogeneous climate-vegetation conditions were identified using Fuzzy C-Means algorithm; (2) SPEI and NDVI's annual Rmax were in significantly positive correlation in most regions of China, indicating that vegetation biomass were influenced mainly by the spatiotemporal characteristics of the water availability. The southeastern Yangtze River basin and the lower Pearl River basin are dominated by abundant precipitation, and vegetation is not sensitive to droughts in these regions. The northeastern Heilongjiang province, the Changbai Mountains and western Sichuan province are characterized by weak NDVI versus SPEI relations, indicating a relatively small effect of drought on vegetation; (3) The effects of annual average water balance, annual average annual precipitation, annual average effective accumulative temperature, and annual average daily sunshine hours on the NDVI versus SPEI correlation show that the annual average water balance is the key factor behind the change of vegetation vigor. It can therefore be concluded that the change of water availability is the key factor behind the change of vegetation activity and biomass. Regional precipitation or water balance was significantly related to the correlation between SPEI and NDVI. Vegetation in the regions with longer sunshine hours is more sensitive to droughts. In general, the sensitivity of grassland to droughts is the largest, followed by the sensitivity of shrubs and forests to droughts.

  5. The Effect of Skill Complexity during Different Time Lags on Bilateral Transfer

    Directory of Open Access Journals (Sweden)

    Zahra Zolfaghari

    2014-04-01

    Full Text Available The present paper aims to study the effect of skill complexity during different delays on bidirectional transfer on bidirectional transfer of tracking task in different stages (pretest, acquisition phase, immediate transfer, one-day delayed transfer, two-day delayed transfer, and seven-day delayed transfer. Three variables including handedness, time lagges, and skill complexity were studied. This study was a semi-empirical and applied research and a pretest-posttest plan with two experimental groups was used. Statistical sample included 28 volunteer girl students, with a mean age of 16±0.93 years old, who were all right-handed and had no experience of performing the tracking task. After initial familiarization with designed software, the subjects were randomly divided into two groups of right practice and left practice. The results revealed significant effects of time lags and skill complexity on bidirectional transfer (p≤0.05, as at all stages of research more bidirectional transfer was observed in easy task compared with the hard one. The highest bilateral transfer in easy and hard tasks was found in the second and the seventh day, respectively. Possible reasons for these results include the differences in task processing in terms of skill complexity and the impact of special features of continuous task on retention. Transfer from non-dominant hand to dominant one occurred more frequently than the reverse mode in both groups, which is probably due to higher speed of transfer of data from the right hemisphere to the left hemisphere in the right-handed.

  6. Investigation of Vegetation Dynamics using Long-Term Normalized Difference Vegetation Index Time-Series

    Directory of Open Access Journals (Sweden)

    Tamara Bellone

    2009-01-01

    Full Text Available Problem statement: The Normalized Difference Vegetation Index (NDVI is the most extensively used satellite-derived index of vegetation health and density. Since climate is one of the most important factors affecting vegetation condition, satellite-derived vegetation indexes have been often used to evaluate climatic and environmental changes at regional and global scale. The proposed study attempted to investigate the temporal vegetation dynamics in the whole Africa using historical NDVI time-series. Approach: For this aim, 15 day maximum value NDVI composites at 8 km spatial resolution produced from the NASA Global Inventory Mapping and Monitoring System (GIMMS had been used. They were derived from data collected daily by NOAA AVHRR satellites. The AVHRR NDVI GIMMS dataset was freely available and gives global coverage over an extensive time period. First of all, the selected NDVI base data had been geometrically pre-processed and organized into a historical database implemented in order to grant their spatial integration. Starting from this archive, monthly and yearly NDVI historical time-series, extended from 1982-2006, had been then developed and analysed on a pixel basis. Several routines hade been developed in IDL (Interactive Data Language programming tool with the purpose of applying suitable statistical analysis techniques to the historical information in the database in order to identify the long-term trend components of generated NDVI time-series and extract vegetation dynamics. Specific tests had been then considered in order to define the validity of results. Results: The existence of clear regional trends of NDVI, both decreasing and increasing had been showed, which helped to highlight areas subject, respectively to reduction or increase in vegetation greenness. Conclusion: As the relationship between the NDVI and vegetation productivity was well established, these estimated long-term trend components may be also, with much more

  7. Different Types of Employee Well-Being Across Time and Their Relationships With Job Crafting.

    Science.gov (United States)

    Hakanen, Jari J; Peeters, Maria C W; Schaufeli, Wilmar B

    2017-02-13

    We used and integrated the circumplex model of affect (Russell, 1980) and the conservation of resources theory (Hobfoll, 1998) to hypothesize how various types of employee well-being, which can be differentiated on theoretical grounds (i.e., work engagement, job satisfaction, burnout, and workaholism), may differently predict various job crafting behaviors (i.e., increasing structural and social resources and challenging demands, and decreasing hindering demands) and each other over time. At Time 1, we measured employee well-being, and 4 years later at Time 2, job crafting and well-being, using a large sample of Finnish dentists (N = 1,877). The results of structural equation modeling showed that (a) work engagement positively predicted both types of increasing resources and challenging demands and negatively predicted decreasing hindering demands; (b) workaholism positively predicted increasing structural resources and challenging demands; (c) burnout positively predicted decreasing hindering demands and negatively predicted increasing structural resources, whereas (d) job satisfaction did not relate to job crafting over time; and (e) work engagement positively influenced job satisfaction and negatively influenced burnout, whereas (f) workaholism predicted burnout after controlling for baseline levels. Thus, work engagement was a stronger predictor of future job crafting and other types of employee well-being than job satisfaction. Although workaholism was positively associated with job crafting, it also predicted burnout. We conclude that the relationship between job crafting and employee well-being may be more complex than assumed, because the way in which employees will craft their jobs in the future seems to depend on how they currently feel. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  8. The effect of β-alanine supplementation on cycling time trials of different length.

    Science.gov (United States)

    Bellinger, Phillip M; Minahan, Clare L

    2016-10-01

    The varying results reported in response to β-alanine supplementation may be related to the duration and nature of the exercise protocol employed. We investigated the effects of β-alanine supplementation on a wide range of cycling performance tests in order to produce a clear concise set of criteria for its efficacy. Fourteen trained cyclists (Age = 24.8 ± 6.7 years; VO2max = 65.4 ± 10.2 mL·kg·min(-1)) participated in this placebo-controlled, double-blind study. Prior to supplementation, subjects completed two (familiarization and baseline) supramaximal cycling bouts until exhaustion (120% pre-supplementation VO2max) and two 1-, 4- and 10-km cycling time trial (TT). Subjects then supplemented orally for 4 weeks with 6.4 g/d placebo or β-alanine and repeated the battery of performance tests. Blood lactate was measured pre-exercise, post-exercise and 5  min post-exercise. β-alanine supplementation elicited significant increases in time to exhaustion (TTE) (17.6 ± 11.5 s; p = 0.013, effect compared with placebo) and was likely to be beneficial to 4-km TT performance time (-7.8 ± 8.1 s; 94% likelihood), despite not being statistically different (p = 0.060). Performance times in the 1- and 10-km TT were not affected by treatment. For the highly trained cyclists in the current study, β-alanine supplementation significantly extended supramaximal cycling TTE and may have provided a worthwhile improvement to 4-km TT performance. However, 1- and 10-km cycling TT performance appears to be unaffected by β-alanine supplementation.

  9. Comparison of Different Techniques for Processing GNSS Data in Real Time for Tsunami Warning

    Science.gov (United States)

    Schmidt, M.; Dragert, H.; Lu, Y.; Henton, J.; MacLeod, K.

    2012-12-01

    Real-time processing and dissemination of GNSS derived co-seismic position offsets for tsunami early warning has been under development at the Geological Survey of Canada (NRCan) for the past six years. Using streamed data from the Western Canada Deformation Array (WCDA), results from two variations of Precise Point Positioning (PPP) and two variations of network-based solutions are evaluated: NRCan's real-time PPP software, and two commercial software packages RTD and RTNET, licensed from Geodetics Inc. and GPS Solutions Inc. respectively. Of the two commercial packages, the former provides independent, epoch-by-epoch network solutions, while the latter has the capability to process data using both PPP and Network approaches. There are clear advantages and disadvantages to the independent PPP solutions vs. the network based solutions. PPP solutions (smoothed and un-smoothed) provide position estimates for single stations in a global framework. They are not reliant on 'fixed' reference stations that, if located within the seismogenic zone, will clearly experience co-seismic displacements. Under best-case scenarios, error levels of 1-2 cm horizontal and 3-6cm vertical are achievable for network based solutions whereas PPP solutions with ambiguity resolution are currently somewhat noisier. Both analysis methodologies are critically dependent on data continuity and robust tracking of all available satellites at each site. A clear case is made for the requirement for network based processing capacity for baselines of greater than 150km in order to ensure robust co-seismic displacement estimates during large earthquakes. Results from tests within the WCDA network using the different techniques are presented as well as recommendations for computational and operational improvements. NRCan's real-time web based interface offers the user community with a real-time display of position offset estimates for sites in southwestern coastal British Columbia.

  10. Further development of the attitude difference method for estimating deflections of the vertical in real time

    Science.gov (United States)

    Zhu, Jing; Zhou, Zebo; Li, Yong; Rizos, Chris; Wang, Xingshu

    2016-07-01

    An improvement of the attitude difference method (ADM) to estimate deflections of the vertical (DOV) in real time is described in this paper. The ADM without offline processing estimates the DOV with a limited accuracy due to the response delay. The proposed model selection-based self-adaptive delay feedback (SDF) method takes the results of the ADM as the a priori information, then uses fitting and extrapolation to estimate the DOV at the current epoch. The active region selection factor F th is used to take full advantage of the Earth model EGM2008 and the SDF with different DOV exhibitions. The factors which affect the DOV estimation accuracy are analyzed and modeled. An external observation which is specified by the velocity difference between the global navigation satellite system (GNSS) and the inertial navigation system (INS) with DOV compensated is used to select the optimal model. The response delay induced by the weak observability of an integrated INS/GNSS to the violent DOV disturbances in the ADM is compensated. The DOV estimation accuracy of the SDF method is improved by approximately 40% and 50% respectively compared to that of the EGM2008 and the ADM. With an increase in GNSS accuracy, the DOV estimation accuracy could improve further.

  11. Contour Detection-Based Realistic Finite-Difference-Time- Domain Models for Microwave Breast Cancer Detection

    Institute of Scientific and Technical Information of China (English)

    王梁; 肖夏; 宋航; 路红; 刘佩芳

    2016-01-01

    In this paper, a collection of three-dimensional(3D)numerical breast models are developed based on clinical magnetic resonance images(MRIs). A hybrid contour detection method is used to create the contour, and the internal space is filled with different breast tissues, with each corresponding to a specified interval of MRI pixel intensity. The developed models anatomically describe the complex tissue structure and dielectric properties in breasts. Besides, they are compatible with finite-difference-time-domain(FDTD)grid cells. Convolutional perfect matched layer(CPML)is applied in conjunction with FDTD to simulate the open boundary outside the model. In the test phase, microwave breast cancer detection simulations are performed in four models with varying radio-graphic densities. Then, confocal algorithm is utilized to reconstruct the tumor images. Imaging results show that the tumor voxels can be recognized in every case, with 2 mm location error in two low density cases and 7 mm─8 mm location errors in two high density cases, demonstrating that the MRI-derived models can characterize the indi-vidual difference between patients’ breasts.

  12. Monthly Rainfall Erosivity: Conversion Factors for Different Time Resolutions and Regional Assessments

    Directory of Open Access Journals (Sweden)

    Panos Panagos

    2016-03-01

    Full Text Available As a follow up and an advancement of the recently published Rainfall Erosivity Database at European Scale (REDES and the respective mean annual R-factor map, the monthly aspect of rainfall erosivity has been added to REDES. Rainfall erosivity is crucial to be considered at a monthly resolution, for the optimization of land management (seasonal variation of vegetation cover and agricultural support practices as well as natural hazard protection (landslides and flood prediction. We expanded REDES by 140 rainfall stations, thus covering areas where monthly R-factor values were missing (Slovakia, Poland or former data density was not satisfactory (Austria, France, and Spain. The different time resolutions (from 5 to 60 min of high temporal data require a conversion of monthly R-factor based on a pool of stations with available data at all time resolutions. Because the conversion factors show smaller monthly variability in winter (January: 1.54 than in summer (August: 2.13, applying conversion factors on a monthly basis is suggested. The estimated monthly conversion factors allow transferring the R-factor to the desired time resolution at a European scale. The June to September period contributes to 53% of the annual rainfall erosivity in Europe, with different spatial and temporal patterns depending on the region. The study also investigated the heterogeneous seasonal patterns in different regions of Europe: on average, the Northern and Central European countries exhibit the largest R-factor values in summer, while the Southern European countries do so from October to January. In almost all countries (excluding Ireland, United Kingdom and North France, the seasonal variability of rainfall erosivity is high. Very few areas (mainly located in Spain and France show the largest from February to April. The average monthly erosivity density is very large in August (1.67 and July (1.63, while very small in January and February (0.37. This study addresses

  13. T(2) relaxation time of hyaline cartilage in presence of different gadolinium-based contrast agents.

    Science.gov (United States)

    Wiener, Edzard; Settles, Marcus; Diederichs, Gerd

    2010-01-01

    The transverse relaxation time, T(2), of native cartilage is used to quantify cartilage degradation. T(2) is frequently measured after contrast administration, assuming that the impact of gadolinium-based contrast agents on cartilage T(2) is negligible. To verify this assumption the depth-dependent variation of T(2) in the presence of gadopentetate dimeglumine, gadobenate dimeglumine and gadoteridol was investigated. Furthermore, the r(2)/r(1) relaxivity ratios were quantified in different cartilage layers to demonstrate differences between T(2) and T(1) relaxation effects. Transverse high-spatial-resolution T(1)- and T(2)-maps were simultaneously acquired on a 1.5 T MR scanner before and after contrast administration in nine bovine patellae using a turbo-mixed sequence. The r(2)/r(1) ratios were calculated for each contrast agent in cartilage. Profiles of T(1), T(2) and r(2)/r(1) across cartilage thickness were generated in the absence and presence of contrast agent. The mean values in different cartilage layers were compared for global variance using the Kruskal-Wallis test and pairwise using the Mann-Whitney U-test. T(2) of unenhanced cartilage was 98 +/- 5 ms at 1 mm and 65 +/- 4 ms at 3 mm depth. Eleven hours after contrast administration significant differences (p cartilage thickness were close to 1.0 (range 0.9-1.3). At 1.5 T, T(2) decreased significantly in the presence of contrast agents, more pronounced in superficial than in deep cartilage. The change in T(2) relaxation rate was similar to the change in T(1). Cartilage T(2) measurements after contrast administration will lead to systematic errors in the quantification of cartilage degradation. 2010 John Wiley & Sons, Ltd.

  14. Finite-Difference Time-Domain Simulation for Three-dimensional Polarized Light Imaging

    CERN Document Server

    Menzel, Miriam; De Raedt, Hans; Michielsen, Kristel

    2016-01-01

    Three-dimensional Polarized Light Imaging (3D-PLI) is a promising technique to reconstruct the nerve fiber architecture of human post-mortem brains from birefringence measurements of histological brain sections with micrometer resolution. To better understand how the reconstructed fiber orientations are related to the underlying fiber structure, numerical simulations are employed. Here, we present two complementary simulation approaches that reproduce the entire 3D-PLI analysis: First, we give a short review on a simulation approach that uses the Jones matrix calculus to model the birefringent myelin sheaths. Afterwards, we introduce a more sophisticated simulation tool: a 3D Maxwell solver based on a Finite-Difference Time-Domain algorithm that simulates the propagation of the electromagnetic light wave through the brain tissue. We demonstrate that the Maxwell solver is a valuable tool to better understand the interaction of polarized light with brain tissue and to enhance the accuracy of the fiber orientati...

  15. Computation of the acoustic radiation force using the finite-difference time-domain method.

    Science.gov (United States)

    Cai, Feiyan; Meng, Long; Jiang, Chunxiang; Pan, Yu; Zheng, Hairong

    2010-10-01

    The computational details related to calculating the acoustic radiation force on an object using a 2-D grid finite-difference time-domain method (FDTD) are presented. The method is based on propagating the stress and velocity fields through the grid and determining the energy flow with and without the object. The axial and radial acoustic radiation forces predicted by FDTD method are in excellent agreement with the results obtained by analytical evaluation of the scattering method. In particular, the results indicate that it is possible to trap the steel cylinder in the radial direction by optimizing the width of Gaussian source and the operation frequency. As the sizes of the relating objects are smaller than or comparable to wavelength, the algorithm presented here can be easily extended to 3-D and include torque computation algorithms, thus providing a highly flexible and universally usable computation engine.

  16. Dispersive finite-difference time-domain (FDTD) analysis of the elliptic cylindrical cloak

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. Y.; Ahn, D. [University of Seoul, Seoul (Korea, Republic of)

    2012-05-15

    A dispersive full-wave finite-difference time-domain (FDTD) model is used to calculate the performance of elliptic cylindrical cloaking devices. The permittivity and the permeability tensors for the cloaking structure are derived by using an effective medium approach in general relativity. The elliptic cylindrical invisibility devices are found to show imperfect cloaking, and the cloaking performance is found to depend on the polarization of the incident waves, the direction of the propagation of those waves, the semi-focal distances and the loss tangents of the meta-material. When the semifocal distance of the elliptic cylinder decreases, the performance of the cloaking becomes very good, with neither noticeable scatterings nor field penetrations. For a larger semi-focal distance, only the TM wave with a specific propagation direction shows good cloaking performance. Realistic cloaking materials with loss still show a cloak that is working, but attenuated back-scattering waves exist.

  17. Finite difference time domain method forward simulation of complex geoelectricity ground penetrating radar model

    Institute of Scientific and Technical Information of China (English)

    DAI Qian-wei; FENG De-shan; HE Ji-shan

    2005-01-01

    The ground penetrating radar(GPR) forward simulation all aims at the singular and regular models, such as sandwich model, round cavity, square cavity, and so on, which are comparably simple. But as to the forward of curl interface underground or "v" figure complex model, it is difficult to realize. So it is important to forward the complex geoelectricity model. This paper takes two Maxwell's vorticity equations as departure point, makes use of the principles of Yee's space grid model theory and the basic principle finite difference time domain method, and deduces a GPR forward system of equation of two dimensional spaces. The Mur super absorbed boundary condition is adopted to solve the super strong reflection on the interceptive boundary when there is the forward simulation. And a self-made program is used to process forward simulation to two typical geoelectricity model.

  18. Acoustic Analyses and Intelligibility Assessments of Timing Patterns Among Chinese English Learners with Different Dialect Backgrounds.

    Science.gov (United States)

    Chen, Hsueh Chu

    2015-12-01

    This paper includes two interrelated studies. The first production study investigates the timing patterns of English as spoken by Chinese learners with different dialect backgrounds. The second comprehension study explores native and non-native speakers' assessments of the intelligibility of Chinese-accented English, and examines the effects of the listeners' language backgrounds on their perceptions of Chinese-accented English. The results showed that the Hong Kong (HK) group performed better in unstressed syllable duration compared with the Taiwan (TW) and Beijing (BJ) groups. The results also revealed that all six listener groups achieved at least 78% intelligibility, with the native speaker accent achieving the highest rating, followed by the HK, TW, and BJ accents. A shared first language (L1) background may have little or no impact on intelligibility. The speech properties might prevail over the shared L1 effect. All listeners perceived inappropriate word-stress shift and consonant cluster simplifications to be the most unintelligible features.

  19. Efficient Non-Uniform Orthogonal Mesh Generation Algorithm for Cylindrical Finite Difference Time Domain Applications

    Institute of Scientific and Technical Information of China (English)

    ZHOU Guoxiang; CHEN Yinchao; SHEN Guoqiang

    2001-01-01

    The paper presents an efficient andfast non-uniform, orthogonal mesh generation algo-rithm for the analysis and design of cylindrical mi-crowave devices and integrated circuits using thecylindrical finite-difference time-domain (CFDTD)methods. By using this algorithm, we can easily gen-erate a suitable CFDTD grid fitting for the devel-oped CFDTD Maxwell's solver. In the paper, wewill introduce in detail the algorithm and the graph-ical functions of the corresponding software package,CylinMesh. In addition, we will illustrate the algo-rithm by demonstrating various one, two, and three-dimensional grid patterns for a double-layered cylin-drical microstrip stepped-impedance low pass filter.

  20. The analysis of reactively loaded microstrip antennas by finite difference time domain modelling

    Science.gov (United States)

    Hilton, G. S.; Beach, M. A.; Railton, C. J.

    1990-01-01

    In recent years, much interest has been shown in the use of printed circuit antennas in mobile satellite and communications terminals at microwave frequencies. Although such antennas have many advantages in weight and profile size over more conventional reflector/horn configurations, they do, however, suffer from an inherently narrow bandwidth. A way of optimizing the bandwidth of such antennas by an electronic tuning technique using a loaded probe mounted within the antenna structure is examined, and the resulting far-field radiation patterns are shown. Simulation results from a 2D finite difference time domain (FDTD) model for a rectangular microstrip antenna loaded with shorting pins are given and compared to results obtained with an actual antenna. It is hoped that this work will result in a design package for the analysis of microstrip patch antenna elements.

  1. The time-dependent Ginzburg-Landau equation for the two-velocity difference model

    Institute of Scientific and Technical Information of China (English)

    Wu Shu-zhen; Cheng Rong-Jun; Ge Hong-xia

    2011-01-01

    A thermodynamic theory is formulated to describe the phase transition and critical phenomenon in traffic flow.Based on the two-velocity difference model,the time-dependent Ginzburg-Landau(TDGL)equation under certain condition is derived to describe the traffic flow near the critical point through the nonlinear analytical method.The corresponding two solutions,the uniform and the kink solutions,are given.The coexisting curve,spinodal line and critical point are obtained by the first and second derivatives of the thermodynamic potential.The modified Kortewegde Vries(mKdV)equation around the critical point is derived by using the reductive perturbation method and its kink-antikink solution is also obtained.The relation between the TDGL equation and the mKdV equation is shown.The simulation result is consistent with the nonlinear analytical result.

  2. Modeling laser-induced periodic surface structures: Finite-difference time-domain feedback simulations

    Energy Technology Data Exchange (ETDEWEB)

    Skolski, J. Z. P., E-mail: j.z.p.skolski@utwente.nl; Vincenc Obona, J. [Materials innovation institute M2i, Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Römer, G. R. B. E.; Huis in ' t Veld, A. J. [Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2014-03-14

    A model predicting the formation of laser-induced periodic surface structures (LIPSSs) is presented. That is, the finite-difference time domain method is used to study the interaction of electromagnetic fields with rough surfaces. In this approach, the rough surface is modified by “ablation after each laser pulse,” according to the absorbed energy profile, in order to account for inter-pulse feedback mechanisms. LIPSSs with a periodicity significantly smaller than the laser wavelength are found to “grow” either parallel or orthogonal to the laser polarization. The change in orientation and periodicity follow from the model. LIPSSs with a periodicity larger than the wavelength of the laser radiation and complex superimposed LIPSS patterns are also predicted by the model.

  3. Modeling laser-induced periodic surface structures: Finite-difference time-domain feedback simulations

    Science.gov (United States)

    Skolski, J. Z. P.; Römer, G. R. B. E.; Vincenc Obona, J.; Huis in't Veld, A. J.

    2014-03-01

    A model predicting the formation of laser-induced periodic surface structures (LIPSSs) is presented. That is, the finite-difference time domain method is used to study the interaction of electromagnetic fields with rough surfaces. In this approach, the rough surface is modified by "ablation after each laser pulse," according to the absorbed energy profile, in order to account for inter-pulse feedback mechanisms. LIPSSs with a periodicity significantly smaller than the laser wavelength are found to "grow" either parallel or orthogonal to the laser polarization. The change in orientation and periodicity follow from the model. LIPSSs with a periodicity larger than the wavelength of the laser radiation and complex superimposed LIPSS patterns are also predicted by the model.

  4. The Newsvendor Problem with Different Delivery Time, Resalable Returns, and an Additional Order

    Directory of Open Access Journals (Sweden)

    Fue Zeng

    2015-01-01

    Full Text Available In a B2C scenario, the retailer is confronted with two kinds of demand. One requires an immediate delivery after placing an order, while the other prefers a delayed shipment due to some personal reasons. Considering demands for different delivery time, we explore a newsvendor model with resalable returns and an additional order to optimize the procurement decision under a stochastic demand distribution. The impact of the proportion of the instant delivery needs and the return rate on the order quantity and the expected profit is illustrated through numerical tests. It is shown that the expected profit decreases as the ratios of immediate delivery needs and returned products increase. Besides, if the sum of the percentage of the instant delivery needs and the return rate is less than 1, the expected profit is always greater than the result if the sum of them is equal to or greater than 1. Management implications are also discussed.

  5. The Coupled Model Predictability of the Western North Pacific Summer Monsoon with Different Leading Times

    Institute of Scientific and Technical Information of China (English)

    LU Ri-Yu; LI Chao-Fan; Se-Hwan YANG; Buwen DONG

    2012-01-01

    Leading time length is an important issue for modeling seasonal forecasts. In this study, a comparison of the interannual predictability of the Western North Pacific (WNP) summer monsoon between different leading months was performed by using one-, four-, and sevenmonth lead retrospective forecasts (hindcasts) of four coupled models from Ensembles-Based Predictions of Climate Changes and Their Impacts (ENSEMBLES) for the period of 1960 2005. It is found that the WNP summer anomalies, including lower-tropospheric circulation and precipitation anomalies, can be well predicted for all these leading months. The accuracy of the four-month lead prediction is only slightly weaker than that of the one-month lead prediction, although the skill decreases with the increase of leading months.

  6. Simulation of acoustic streaming by means of the finite-difference time-domain method

    DEFF Research Database (Denmark)

    Santillan, Arturo Orozco

    2012-01-01

    Numerical simulations of acoustic streaming generated by a standing wave in a narrow twodimensional cavity are presented. In this case, acoustic streaming arises from the viscous boundary layers set up at the surfaces of the walls. It is known that streaming vortices inside the boundary layer have...... directions of rotation that are opposite to those of the outer streaming vortices (Rayleigh streaming). The general objective of the work described in this paper has been to study the extent to which it is possible to simulate both the outer streaming vortices and the inner boundary layer vortices using...... the finite-difference time-domain method. To simplify the problem, thermal effects are not considered. The motivation of the described investigation has been the possibility of using the numerical method to study acoustic streaming, particularly under non-steady conditions. Results are discussed for channels...

  7. Full-wave finite-difference time-domain simulation of electromagnetic cloaking structures.

    Science.gov (United States)

    Zhao, Yan; Argyropoulos, Christos; Hao, Yang

    2008-04-28

    This paper proposes a radial dependent dispersive finite-difference time-domain method for the modeling of electromagnetic cloaking structures. The permittivity and permeability of the cloak are mapped to the Drude dispersion model and taken into account in dispersive FDTD simulations. Numerical simulations demonstrate that under ideal conditions, objects placed inside the cloak are 'invisible' to external electromagnetic fields. However for the simplified cloak based on linear transformations, the back scattering has a similar level to the case of a PEC cylinder without any cloak, rendering the object still being 'visible'. It is also demonstrated numerically that the simplified cloak based on high-order transformations can indeed improve the cloaking performance.

  8. Judgments of damage to public versus private property in Chinese children at different historical times.

    Science.gov (United States)

    Chen, Xinyin; Li, Dan; Liu, Junsheng; Chen, Huichang; Zhao, Siman

    2016-12-15

    This study examined children's judgments of damage to public versus private property in China at two historical times. Participants were two cohorts (1980 and 2012) of elementary school children at ages 7, 9, and 11 years. The children were administered paired stories that described a protagonist who damaged public or private property with a good or bad intention. The results showed that children in the 2012 cohort were less likely than their counterparts in the 1980 cohort to judge damage to public property as more culpable than damage to private property. The cohort differences were more evident in older children than in younger children. The results suggest that macro-level contexts may play an important role in shaping children's judgments.

  9. The Impacts of Heatwaves on Mortality Differ with Different Study Periods: A Multi-City Time Series Investigation.

    Science.gov (United States)

    Wang, Xiao Yu; Guo, Yuming; FitzGerald, Gerry; Aitken, Peter; Tippett, Vivienne; Chen, Dong; Wang, Xiaoming; Tong, Shilu

    2015-01-01

    Different locations and study periods were used in the assessment of the relationships between heatwaves and mortality. However, little is known about the comparability and consistency of the previous effect estimates in the literature. This study assessed the heatwave-mortality relationship using different study periods in the three largest Australian cities (Brisbane, Melbourne and Sydney). Daily data on climatic variables and mortality for the three cities were obtained from relevant government agencies between 1988 and 2011. A consistent definition of heatwaves was used for these cities. Poisson generalised additive model was fitted to assess the impact of heatwaves on mortality. Non-accidental and circulatory mortality significantly increased during heatwaves across the three cities even with different heatwave definitions and study periods. Using the summer data resulted in the largest increase in effect estimates compared to those using the warm season or the whole year data. The findings may have implications for developing standard approaches to evaluating the heatwave-mortality relationship and advancing heat health warning systems. It also provides an impetus to methodological advance for assessing climate change-related health consequences.

  10. The Impacts of Heatwaves on Mortality Differ with Different Study Periods: A Multi-City Time Series Investigation.

    Directory of Open Access Journals (Sweden)

    Xiao Yu Wang

    Full Text Available Different locations and study periods were used in the assessment of the relationships between heatwaves and mortality. However, little is known about the comparability and consistency of the previous effect estimates in the literature. This study assessed the heatwave-mortality relationship using different study periods in the three largest Australian cities (Brisbane, Melbourne and Sydney.Daily data on climatic variables and mortality for the three cities were obtained from relevant government agencies between 1988 and 2011. A consistent definition of heatwaves was used for these cities. Poisson generalised additive model was fitted to assess the impact of heatwaves on mortality.Non-accidental and circulatory mortality significantly increased during heatwaves across the three cities even with different heatwave definitions and study periods. Using the summer data resulted in the largest increase in effect estimates compared to those using the warm season or the whole year data.The findings may have implications for developing standard approaches to evaluating the heatwave-mortality relationship and advancing heat health warning systems. It also provides an impetus to methodological advance for assessing climate change-related health consequences.

  11. A Different Look at Dark Energy and the Time Variation of Fundamental Constants

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Marvin; /SLAC

    2011-02-07

    This paper makes the simple observation that a fundamental length, or cutoff, in the context of Friedmann-Lemaitre-Robertson-Walker (FRW) cosmology implies very different things than for a static universe. It is argued that it is reasonable to assume that this cutoff is implemented by fixing the number of quantum degrees of freedom per co-moving volume (as opposed to a Planck volume) and the relationship of the vacuum-energy of all of the fields in the theory to the cosmological constant (or dark energy) is re-examined. The restrictions that need to be satisfied by a generic theory to avoid conflicts with current experiments are discussed, and it is shown that in any theory satisfying these constraints knowing the difference between w and minus one allows one to predict w. It is argued that this is a robust result and if this prediction fails the idea of a fundamental cutoff of the type being discussed can be ruled out. Finally, it is observed that, within the context of a specific theory, a co-moving cutoff implies a predictable time variation of fundamental constants. This is accompanied by a general discussion of why this is so, what are the strongest phenomenological limits upon this predicted variation, and which limits are in tension with the idea of a co-moving cutoff. It is pointed out, however, that a careful comparison of the predicted time variation of fundamental constants is not possible without restricting to a particular model field-theory and that is not done in this paper.

  12. Time course of auditory streaming: Do CI users differ from normal-hearing listeners?

    Directory of Open Access Journals (Sweden)

    Martin eBöckmann-Barthel

    2014-07-01

    Full Text Available In a complex acoustical environment with multiple sound sources the auditory system uses streaming as a tool to organize the incoming sounds in one or more streams depending on the stimulus parameters. Streaming is commonly studied by alternating sequences of signals. These are often tones with different frequencies. The present study investigates stream segregation in cochlear implant (CI users, where hearing is restored by electrical stimulation of the auditory nerve. CI users listened to 30-s long sequences of alternating A and B harmonic complexes at four different fundamental frequency separations, ranging from 2 to 14 semitones. They had to indicate as promptly as possible after sequence onset, if they perceived one stream or two streams and, in addition, any changes of the percept throughout the rest of the sequence. The conventional view is that the initial percept is always that of a single stream which may after some time change to a percept of two streams. This general build-up hypothesis has recently been challenged on the basis of a new analysis of data of normal-hearing listeners which showed a build-up response only for an intermediate frequency separation. Using the same experimental paradigm and analysis, the present study found that the results of CI users agree with those of the normal-hearing listeners: (i the probability of the first decision to be a one-stream percept decreased and that of a two-stream percept increased as Δf increased, and (ii a build-up was only found for 6 semitones. Only the time elapsed before the listeners made their first decision of the percept was prolonged as compared to normal-hearing listeners. The similarity in the data of the CI user and the normal-hearing listeners indicates that the quality of stream formation is similar in these groups of listeners.

  13. Efficacy of Microwave Disinfection on Moist and Dry Dental Stone Casts with Different Irradiation Times

    Directory of Open Access Journals (Sweden)

    Mahmood Robati Anaraki

    2015-07-01

    Full Text Available Objectives: Dental practice contains the use of instruments and multiuse items that should be sterilized or disinfected properly. The aim of the current study was to investigate the effect of microwave irradiation on dental stone cast disinfection in moist and dry condition. Materials and Methods: In this in vitro study, 76 stone casts were prepared by a sterile method. The casts were contaminated by Pseudomonas aeruginosa (ATCC 9027, Staphylococcus aureus (ATCC 6538, Enterococcus faecalis (ATCC 29212 as well as Candida albicans (ATCC 10231. Half the samples were dried for two hours and the other half was studied while still moist. The samples were irradiated by a household microwave at 600 W for 3, 5 and 7 minutes. The microorganisms on the samples were extracted by immersion in tryptic soy broth and .001 ml of that was cultured in nutrient agar media, incubated overnight and counted and recorded as colony forming unit per milliliter (CFU/mL. Results: The findings showed that microorganisms reduced to 4.87 logarithm of CFU/mL value on dental cast within seven minutes in comparison with positive control. Although microbial count reduction was observed as a result of exposure time increase, comparison between moist and dried samples showed no significant difference. Conclusions: Seven-minute microwave irradiation at 600 W can effectively reduce the microbial load of dental stone casts. Wetting the casts does not seem to alter the efficacy of irradiation.   Keywords: Microwave Disinfection; Dental Stone Casts; Irradiation Times

  14. An individual differences approach to the suggestibility of memory over time.

    Science.gov (United States)

    Frost, Peter; Nussbaum, Gregory; Loconto, Taylor; Syke, Richard; Warren, Casey; Muise, Christina

    2013-04-01

    We examined how certain personality traits might relate to the formation of suggestive memory over time. We hypothesised that compliance and trust relate to initial acceptance of misinformation as memory, whereas fantasy proneness might relate to integration of misinformation into memory after later intervals (relative to the time of exposure to misinformation). Participants watched an excerpt from a movie--the simulated eyewitness event. They next answered a recall test that included embedded misinformation about the movie. Participants then answered a yes/no recognition test. A week later, participants answered a second yes/no recognition test about the movie (each yes/no recognition test included different questions). Before both recognition tests, participants were warned about the misinformation shown during recall and were asked to base their answer on the movie excerpt only. After completing the second recognition test, participants answered questions from the Neuroticism Extroversion Openness Personality Inventory-3 (McCrae, Costa, & Martin, 2005) and Creative Experiences Questionnaire (Merckelbach, Horselenberg, & Muris, 2001). While compliance correlated with misinformation effects immediately after exposure to misinformation, fantasy-prone personality accounted for more of the variability in false recognition rates than compliance after a 1-week interval.

  15. Electromagnetic wave propagation in Body Area Networks using the Finite-Difference-Time-Domain method.

    Science.gov (United States)

    Bringuier, Jonathan N; Mittra, Raj

    2012-01-01

    A rigorous full-wave solution, via the Finite-Difference-Time-Domain (FDTD) method, is performed in an attempt to obtain realistic communication channel models for on-body wireless transmission in Body-Area-Networks (BANs), which are local data networks using the human body as a propagation medium. The problem of modeling the coupling between body mounted antennas is often not amenable to attack by hybrid techniques owing to the complex nature of the human body. For instance, the time-domain Green's function approach becomes more involved when the antennas are not conformal. Furthermore, the human body is irregular in shape and has dispersion properties that are unique. One consequence of this is that we must resort to modeling the antenna network mounted on the body in its entirety, and the number of degrees of freedom (DoFs) can be on the order of billions. Even so, this type of problem can still be modeled by employing a parallel version of the FDTD algorithm running on a cluster. Lastly, we note that the results of rigorous simulation of BANs can serve as benchmarks for comparison with the abundance of measurement data.

  16. Unconditionally stable finite-difference time-domain methods for modeling the Sagnac effect.

    Science.gov (United States)

    Novitski, Roman; Scheuer, Jacob; Steinberg, Ben Z

    2013-02-01

    We present two unconditionally stable finite-difference time-domain (FDTD) methods for modeling the Sagnac effect in rotating optical microsensors. The methods are based on the implicit Crank-Nicolson scheme, adapted to hold in the rotating system reference frame-the rotating Crank-Nicolson (RCN) methods. The first method (RCN-2) is second order accurate in space whereas the second method (RCN-4) is fourth order accurate. Both methods are second order accurate in time. We show that the RCN-4 scheme is more accurate and has better dispersion isotropy. The numerical results show good correspondence with the expression for the classical Sagnac resonant frequency splitting when using group refractive indices of the resonant modes of a microresonator. Also we show that the numerical results are consistent with the perturbation theory for the rotating degenerate microcavities. We apply our method to simulate the effect of rotation on an entire Coupled Resonator Optical Waveguide (CROW) consisting of a set of coupled microresonators. Preliminary results validate the formation of a rotation-induced gap at the center of a transfer function of a CROW.

  17. Comparison of shear bond strengths of ceramic brackets after different time lags between lasing and debonding.

    Science.gov (United States)

    Tozlu, Murat; Oztoprak, Mehmet Oguz; Arun, Tülin

    2012-11-01

    Laser use is effective in the debonding of ceramic brackets. However, a standardization of the laser debonding techniques used has not yet been implemented. The purpose of this study was to evaluate the effect of the time lag elapsed between lasing and shearing on debonding of ceramic brackets. One hundred polycrystalline ceramic brackets were placed on human premolar teeth, which were randomly divided into five groups of 20. One group was assigned as the control. The Er-YAG laser was applied on each bracket in four experimental groups at 5 W for 6 s with the scanning method. Debonding was performed 1 s, 18 s, 30 s, or 60 s after laser exposure. Shear bond strengths and adhesive remnant index scores were measured. Statistically significant difference was observed between the control and experimental groups when the data for the shear bond strengths was considered (p  0.05). Debonding ceramic brackets after 18 s when lased 6 s using an Er-YAG laser with the scanning method is safe and also suitable for clinical use since three brackets can be debonded at a time in succession.

  18. CLINICAL OBSERVATION ON TREATMENT OF STUBBORN HICCUP BY ACUPUNCTURE WITH DIFFERENT NEEDLE RETAINING TIME

    Institute of Scientific and Technical Information of China (English)

    包飞; 梁中; 王凤琴

    2003-01-01

    Purpose:Observe the effect of different duration of needle-retention on acupuncture treatment of stub-born hiccup. Methods: 85 cases of stubborn hiccup patients are randomly divided into control group (n=40) and treat-rment grcup(n=45) according to their visiting time. For patients of control group, acupuncture needles (in both scalppoints and body acupoints) are retained for 30 min, While for patients of treatment group, the needles inserted in thebody acupoints are retained for 1 hr, and that inserted in scalp-point is retained for more than 6 hrs. The treatment isconducted once daily, continuously for 5 times. Results: The cure rate of treatment group is 88.9% (that for deficiencysyndrome is 85.3%), and that of control group is 65% (that for deficiency syndrome is 53.3% ). There is a significantdifference between two groups in the cure rate (P<0.05). The cure rates for excess syndrome of two groups both are100%. Conclusion: Longer retention of acupuncture needle has a better therapeutic effect for deficiency-syndrome typehiccup.

  19. Detecting Different Types of Directional Land Cover Changes Using MODIS NDVI Time Series Dataset

    Directory of Open Access Journals (Sweden)

    Lili Xu

    2016-06-01

    Full Text Available This study proposed a multi-target hierarchical detection (MTHD method to simultaneously and automatically detect multiple directional land cover changes. MTHD used a hierarchical strategy to detect both abrupt and trend land cover changes successively. First, Grubbs’ test eliminated short-lived changes by considering them outliers. Then, the Brown-Forsythe test and the combination of Tomé’s method and the Chow test were applied to determine abrupt changes. Finally, Sen’s slope estimation coordinated with the Mann-Kendall test detection method was used to detect trend changes. Results demonstrated that both abrupt and trend land cover changes could be detected accurately and automatically. The overall accuracy of abrupt land cover changes was 87.0% and the kappa index was 0.74. Detected trends of land cover change indicated high consistency between NDVI (Normalized Difference Vegetation Index, change trends from LTS (Landsat Thematic Mapper and Enhanced Thematic Mapper Plus time series dataset, and MODIS (Moderate Resolution Imaging Spectroradiometer time series datasets with the percentage of samples indicating consistency of 100%. For cropland, trends of millet yield per unit and average NDVI of cropland indicated high consistency with a linear regression determination coefficient of 0.94 (p < 0.01. Compared with other multi-target change detection methods, the changes detected by the MTHD could be related closely with specific ecosystem changes, reducing the risk of false changes in the area with frequent and strong interannual fluctuations.

  20. A Parallel Algorithm for the Two-Dimensional Time Fractional Diffusion Equation with Implicit Difference Method

    Directory of Open Access Journals (Sweden)

    Chunye Gong

    2014-01-01

    Full Text Available It is very time consuming to solve fractional differential equations. The computational complexity of two-dimensional fractional differential equation (2D-TFDE with iterative implicit finite difference method is O(MxMyN2. In this paper, we present a parallel algorithm for 2D-TFDE and give an in-depth discussion about this algorithm. A task distribution model and data layout with virtual boundary are designed for this parallel algorithm. The experimental results show that the parallel algorithm compares well with the exact solution. The parallel algorithm on single Intel Xeon X5540 CPU runs 3.16–4.17 times faster than the serial algorithm on single CPU core. The parallel efficiency of 81 processes is up to 88.24% compared with 9 processes on a distributed memory cluster system. We do think that the parallel computing technology will become a very basic method for the computational intensive fractional applications in the near future.

  1. Study of broadband THz time-domain spectroscopy at different relative humidity levels

    Institute of Scientific and Technical Information of China (English)

    Chiajen Lin; Ichen Ho; X. C. Zhang

    2012-01-01

    Two detection techniques of broadband terahertz (THz) time-domain spectroscopy-THz air-biased coherent detection (THz-ABCD; from 0.3 to 14 THz) and electro-optical (EO) detection (from 0.3 to 7 THz) - are both performed at several different relative humidity levels.The THz power exponentially decays with the increase in relative humidity.The dynamic range of the main pulse in the time domain linearly decreases as the relative humidity increases from 0% to 40%,and linear fittings show that the slopes are -0.017 and -0.019 for THz-ABCD and EO detection,respectively.Because of the multiple reflections caused by the crystal in the common EO detection,THz-ABCD has better spectral resolution (17 GHz) than that of EO detection (170 GHz).The spectrum of water vapor absorption measured by THz-ABCD is also compared with that measured by the Fourier transform infrared spectroscopy (FTIR).

  2. Reliability and Analysis of Changes in Bite Marks at Different Time Intervals and Temperature Ranges

    Directory of Open Access Journals (Sweden)

    Parul Khare Sinha

    2017-04-01

    Full Text Available Objectives: The purpose of this study is to assess time-dependent changes in the morphology of bitemarks and to investigate the utility of matching bitemarks on both perishable and non-perishable objects with the passage of time at different temperatures. Subjects and Methods: The study was conducted at Maharana Pratap College of Dentistry and Research Centre, Gwalior, India. 20 volunteers were asked to bite 6 items each. These included perishable and nonperishable items. Perishable items were apple, banana and Burfi, (a milk-based popular sweet confectionary while non-perishable items included wax, clay, and rubber. Photographs were taken with a digital camera at 0-hours and 24-hours after biting these objects at temperature ranges of 24 ºC to 28 ºC and 36 ºC to 40 ºC, respectively. Life-size photographs of these bitten objects were printed on transparent overlays and compared to hand drawn transparencies prepared from suspect dentition using an X-ray viewer. The comparison of all the 960 transparencies was done by two researchers, independently. Results: All objects gave a positive identification of the biter on matching just after biting. After24-hours, all items also showed positive matching except banana and apples. Conclusion: This proposed method is simple, reliable and less technique sensitive. It narrows down the subjectivity of interpretation. It highlights that due to decomposition changes occur in perishable food items and more so in apples and bananas, making bitemarks less reliable evidence.

  3. [Effect on the quality of corn oil in different cooking temperature and time].

    Science.gov (United States)

    Liao, Jing; Wang, Zhu; Liu, Jing; Xiang, Xuesong; Guo, Shiyin; Yang, Yuexin

    2013-05-01

    To research the effect on fatty acid and oxidation products of corn oil under different temperature and time. Corn oil was heated in 140 degrees C, 200 degrees C, 240 degrees C, after 60 s-300 s, then detected the fatty acid, POV and AV. Corn oil was heated in 240 degrees C, after 138 s, the corn oil started to fire, the contains of SFA rised from 14.18 g/100 g to 20.29 g/100 g, the contains of MUFA rised from 28. 30 g/100 g to 33. 33 g/100 g, the contains of PUFA reduced from 53. 13 g/100 g to 28.98 g/100 g, and tFA, POV, AV, TOV arrived to the highest value, they were 11.29 g/100 g, 108.9, 17.12 mmol/kg, 177.37 mmol/kg respectively. As the cooking time and the cooking temperature increased, the MUFA, tFA and the TV of the corn oil increased, on the contrary the PUFA reduced.

  4. Electromagnetic Wave Propagation in Body Area Networks Using the Finite-Difference-Time-Domain Method

    Directory of Open Access Journals (Sweden)

    Raj Mittra

    2012-07-01

    Full Text Available A rigorous full-wave solution, via the Finite-Difference-Time-Domain (FDTD method, is performed in an attempt to obtain realistic communication channel models for on-body wireless transmission in Body-Area-Networks (BANs, which are local data networks using the human body as a propagation medium. The problem of modeling the coupling between body mounted antennas is often not amenable to attack by hybrid techniques owing to the complex nature of the human body. For instance, the time-domain Green’s function approach becomes more involved when the antennas are not conformal. Furthermore, the human body is irregular in shape and has dispersion properties that are unique. One consequence of this is that we must resort to modeling the antenna network mounted on the body in its entirety, and the number of degrees of freedom (DoFs can be on the order of billions. Even so, this type of problem can still be modeled by employing a parallel version of the FDTD algorithm running on a cluster. Lastly, we note that the results of rigorous simulation of BANs can serve as benchmarks for comparison with the abundance of measurement data.

  5. Effect of the thawing time of castor bean pollen grains stored at different temperatures

    Directory of Open Access Journals (Sweden)

    Cristina Copstein Cuchiara

    2012-11-01

    Full Text Available This paper aimed at evaluating the effect of thawing time of pollen grains of castor bean cultivars undergoing different environmental conditions and storage periods. For this, pollen grains were maintained in four environments: refrigerator (4ºC, freezer (-18ºC, ultrafreezer (-72ºC, and liquid nitrogen (-196ºC for 60 days. To evaluate viability, in vitro germination was carried out in three tests: 15, 30, and 60 days, in which the pollens grains germinated within an hour were analyzed up to 6h and after 24h. In a completely randomized design, 100 pollen grains were analyzed in the 6 replications of each treatment. For the cultivar IAC 80, both after 15 and 30 days of storage in ultrafreezer, about 50% of pollen grains germinated required from 5h to 6h of incubation for the resumption of metabolism, respectively. For the cultivar AL Guarany 2002, ultrafreezer presented a higher degree of technical uniformity; however, the best germination was achieved through criopreservation. After 60 days, there was a dramatic decrease in the viability under all environmental conditions. Depending on the temperature, there may be a need for a larger thawing time for the resumption of physiological activities.

  6. The sigmoid volvulus: surgical timing and mortality for different clinical types

    Directory of Open Access Journals (Sweden)

    Spizzirri Alessandro

    2010-01-01

    Full Text Available Abstract Background In western countries intestinal obstruction caused by sigmoid volvulus is rare and its mortality remains significant in patients with late diagnosis. The aim of this work is to assess what is the correct surgical timing and how the prognosis changes for the different clinical types. Methods We realized a retrospective clinical study including all the patients treated for sigmoid volvulus in the Department of General Surgery, St Maria Hospital, Terni, from January 1996 till January 2009. We selected 23 patients and divided them in 2 groups on the basis of the clinical onset: patients with clear clinical signs of obstruction and patients with subocclusive symptoms. We focused on 30-day postoperative mortality in relation to the surgical timing and procedure performed for each group. Results In the obstruction group mortality rate was 44% and it concerned only the patients who had clinical signs and symptoms of peritonitis and that were treated with a sigmoid resection (57%. Conversely none of the patients treated with intestinal derotation and colopexy died. In the subocclusive group mortality was 35% and it increased up to 50% in those patients with a late diagnosis who underwent a sigmoid resection. Conclusions The mortality of patients affected by sigmoid volvulus is related to the disease stage, prompt surgical timing, functional status of the patient and his collaboration with the clinicians in the pre-operative decision making process. Mortality is higher in both obstructed patients with generalized peritonitis and patients affected by subocclusion with late diagnosis and surgical treatment; in both scenarios a Hartmann's procedure is the proper operation to be considered.

  7. Associations among Different Internet Access Time, Gender and Cyberbullying Behaviors in Taiwan’s Adolescents

    Directory of Open Access Journals (Sweden)

    Cheng-Min Chao

    2017-06-01

    Full Text Available With the increasing convenience of social networking sites and their interconnectedness with human interaction, verbal and image bullying have turned digital, making cyberbullying a new form of bullying attracting the attention of researchers, social workers, and schools. This study focuses on the status quo of attitude toward cyberbullying and cyberbullying behavior, explores associations of attitude toward behavior on cyberbullying behavior in gender and different internet access times. In a cross-sectional survey, adolescents were surveyed through self-report questionnaires, 13,864 respondents were received among 150 high schools in Taiwan. Statistical analyses were performed using structural equation modeling (SEM. The study revealed that attitude toward cyberbullying has a direct effect on cyberbullying behavior; among the greatest direct impact were when students use the Internet during the time frame 10:00–14:00. Parents and schoolteachers pay special attention to students using the Internet during this time frame 10:00–14:00 and give guidance, express care, and help those being bullied to communicate and use the Internet in a correct manner. Among genders, male student attitude toward behavior has a greater effect than those of female students. Both male and female students know what cyberbullying is and have witnessed, heard of, or personally encountered cyberbullying behavior. We recommend students talk to parents or teachers or other people who care to reduce the negative effects of cyberbullying. We hopeful that the conceptualization model presented in this study serves as an activator for researches on attitude toward cyberbullying and cyberbullying behavior, and serves a guide and a call to attract more researches in this area.

  8. The cooling time of fertile chicken eggs at different stages of incubation.

    Science.gov (United States)

    Mortola, Jacopo P; Gaonac'h-Lovejoy, Vanda

    2016-01-01

    We asked whether or not the thermal characteristics of fertile avian eggs changed throughout incubation. The cooling and warming times, expressed by the time constant τ of the egg temperature response to a rapid change in ambient temperature, were measured in fertile chicken eggs at early (E7), intermediate (E11) and late (E20) stages of embryonic development. Same measurements were conducted on eggs emptied of their content and refilled with water by various amounts. The results indicated that (1) the τ of a freshly laid egg was ~50 min; (2) τ decreased linearly with the drop in egg water volume; (3) the dry eggshell had almost no thermal resistance but its wet inner membrane contributed about one-third to the stability of egg temperature; (4) the egg constituents (yolk, albumen and embryonic tissues) and the chorioallantoic circulation had no measurable effect on τ; (5) the presence of an air pocket equivalent in volume to the air cell of fertile eggs reduced τ by about 3 min (E7), 5 min (E11) and 11 min (E20). Hence, in response to warming the egg τ at E20 was slightly shorter than at E7. In response to cooling, the egg τ at E20 was similar to, or longer than, E7 because embryonic thermogenesis (evaluated by measurements of oxygen consumption during cold) offset the reduction in τ introduced by the air cell. In conclusion, until the onset of thermogenesis the thermal behavior of a fertile egg is closely approximated by that of a water-filled egg with an air volume equivalent to the air cell. It is possible to estimate the cooling τ of avian eggs of different species from their weight and incubation time. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. The Timing of Vision – How Neural Processing Links to Different Temporal Dynamics

    Directory of Open Access Journals (Sweden)

    Timothée eMasquelier

    2011-06-01

    Full Text Available We review here our recent attempts to model the neural correlates of visual perception with biologically-inspired networks of spiking neurons, emphasizing the dynamical aspects. Experimental evidence suggests distinct processing modes depending on the type of task the visual system is engaged in. A first mode deals with rapidly extracting the glimpse of a visual scene in the first 100ms after its presentation. The promptness of this process points to mainly feedforward processing, which may be shaped by Spike Timing-Dependent Plasticity. Our simulations confirm the plausibility and efficiency of such a scheme. A second mode can be engaged whenever one needs to perform finer perceptual discrimination through evidence accumulation. Here, our simulations, together with theoretical considerations, show how predominantly local recurrent connections and long neural time-constants enable the integration and build-up of firing rates on this timescale. A third mode, involving additional top-down attentional signals, is relevant for more complex visual scene processing. In the model, as in the brain, these top-down attentional signals shape visual processing by biasing the competition between different neuron pools. The winning pools may not only have a higher firing rate, but also more synchronous oscillatory activity. This fourth mode, oscillatory activity, leads to faster reaction times and enhanced information transfers in the model. This has indeed been observed experimentally. Moreover, oscillatory activity can encode information in the spike phases with respect to the oscillatory cycle. This phenomenon is referred to as Phase-of-Firing Coding, and experimental evidence for it is accumulating in the visual system. Simulations show that this code can again be efficiently decoded by STDP. Future work should focus on continuous natural vision, bio-inspired hardware vision systems, and novel experimental paradigms to further distinguish current modeling

  10. Associations among Different Internet Access Time, Gender and Cyberbullying Behaviors in Taiwan’s Adolescents

    Science.gov (United States)

    Chao, Cheng-Min; Yu, Tai-Kuei

    2017-01-01

    With the increasing convenience of social networking sites and their interconnectedness with human interaction, verbal and image bullying have turned digital, making cyberbullying a new form of bullying attracting the attention of researchers, social workers, and schools. This study focuses on the status quo of attitude toward cyberbullying and cyberbullying behavior, explores associations of attitude toward behavior on cyberbullying behavior in gender and different internet access times. In a cross-sectional survey, adolescents were surveyed through self-report questionnaires, 13,864 respondents were received among 150 high schools in Taiwan. Statistical analyses were performed using structural equation modeling (SEM). The study revealed that attitude toward cyberbullying has a direct effect on cyberbullying behavior; among the greatest direct impact were when students use the Internet during the time frame 10:00–14:00. Parents and schoolteachers pay special attention to students using the Internet during this time frame 10:00–14:00 and give guidance, express care, and help those being bullied to communicate and use the Internet in a correct manner. Among genders, male student attitude toward behavior has a greater effect than those of female students. Both male and female students know what cyberbullying is and have witnessed, heard of, or personally encountered cyberbullying behavior. We recommend students talk to parents or teachers or other people who care to reduce the negative effects of cyberbullying. We hopeful that the conceptualization model presented in this study serves as an activator for researches on attitude toward cyberbullying and cyberbullying behavior, and serves a guide and a call to attract more researches in this area. PMID:28713309

  11. Effects of different timing of stress on corticosterone, BDNF and memory in male rats.

    Science.gov (United States)

    Radahmadi, Maryam; Alaei, Hojjatallah; Sharifi, Mohammad Reza; Hosseini, Nasrin

    2015-02-01

    Learning and memory seem to be affected by chronic stress. Previous reports have considered chronic stress as a precipitating factor of different neuropsychological disorders, while others reported neurobiological adaptations following stress. The present study investigated the effects of chronic stress before, after, and during learning on the changes of learning and memory, on serum and hippocampal levels of corticosterone (CORT), brain-derived neurotrophic factor (BDNF) and body weight in rats. Male Wistar rats were randomly divided into four groups (n=10) including Control (Co), Stress-Learning-Rest (St-L-Re), Rest-Learning-Stress (Re-L-St), and Stress-Learning-Stress (St-L-St) groups. The chronic restraint stress was applied 6 h/day for 21 days. Moreover, the passive avoidance test was used to assess memory deficit, 1, 7, and 21 days after training. At the end of experiments, CORT and BDNF levels were measured. The findings did not support adaptation in chronic stress conditions. The acquisition time as well as the short and mid-term memories was significantly impaired in the St-L-Re group. Short, mid, and long-term memories were significantly impaired in the Re-L-St and St-L-St groups compared with the Co group, as a result of the enhancement of CORT and reduction of BDNF levels. In the St-L-St group, changes in memory functions were less pronounced than in the Re-L-St group. Also, body weight declined following the chronic stress, while recovery period enhanced the body weight gain in stressed rats. It can be concluded that a potential time-dependent involvement of stress and recovery period on the level of BDNF. Longer duration time of chronic stress might promote adaptive effects on memory and CORT level. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Background Subtraction and Frame Difference Based Moving Obiect Detection for Real-Time Surveillance

    Institute of Scientific and Technical Information of China (English)

    黄中文; 戚飞虎; 岑峰

    2003-01-01

    A new real-time algorithm is proposed in this paper for detecting moving object in color image sequences taken from stationary cameras. This algorithm combines a temporal difference with an adaptive background subtraction where the combination is novel. When changes occur, the background is automatically adapted to suit the new conditions. For the background model, a new model is proposed with each frame decomposed into regions and the model is based not only upon single pixel but also on the characteristic of a region. The hybrid presentation includes a model for single pixel information and a model for the pixel's neighboring area information.This new model of background can both improve the accuracy of segmentation due to that spatial information is taken into account and saliently speed up the processing procedure because portion of neighboring pixel can be selected into modeling. The algorithm was successfully used in a video surveillance system and the experiment result shows it can obtain a clearer foreground than the single frame difference or background subtraction method.

  13. Estimation of Interchannel Time Difference in Frequency Subbands Based on Nonuniform Discrete Fourier Transform

    Directory of Open Access Journals (Sweden)

    Qiu Bo

    2008-01-01

    Full Text Available Binaural cue coding (BCC is an efficient technique for spatial audio rendering by using the side information such as interchannel level difference (ICLD, interchannel time difference (ICTD, and interchannel correlation (ICC. Of the side information, the ICTD plays an important role to the auditory spatial image. However, inaccurate estimation of the ICTD may lead to the audio quality degradation. In this paper, we develop a novel ICTD estimation algorithm based on the nonuniform discrete Fourier transform (NDFT and integrate it with the BCC approach to improve the decoded auditory image. Furthermore, a new subjective assessment method is proposed for the evaluation of auditory image widths of decoded signals. The test results demonstrate that the NDFT-based scheme can achieve much wider and more externalized auditory image than the existing BCC scheme based on the discrete Fourier transform (DFT. It is found that the present technique, regardless of the image width, does not deteriorate the sound quality at the decoder compared to the traditional scheme without ICTD estimation.

  14. Estimation of Interchannel Time Difference in Frequency Subbands Based on Nonuniform Discrete Fourier Transform

    Directory of Open Access Journals (Sweden)

    Bo Qiu

    2008-05-01

    Full Text Available Binaural cue coding (BCC is an efficient technique for spatial audio rendering by using the side information such as interchannel level difference (ICLD, interchannel time difference (ICTD, and interchannel correlation (ICC. Of the side information, the ICTD plays an important role to the auditory spatial image. However, inaccurate estimation of the ICTD may lead to the audio quality degradation. In this paper, we develop a novel ICTD estimation algorithm based on the nonuniform discrete Fourier transform (NDFT and integrate it with the BCC approach to improve the decoded auditory image. Furthermore, a new subjective assessment method is proposed for the evaluation of auditory image widths of decoded signals. The test results demonstrate that the NDFT-based scheme can achieve much wider and more externalized auditory image than the existing BCC scheme based on the discrete Fourier transform (DFT. It is found that the present technique, regardless of the image width, does not deteriorate the sound quality at the decoder compared to the traditional scheme without ICTD estimation.

  15. Different methods of real-time PCR for detection of pseudorabies virus

    Directory of Open Access Journals (Sweden)

    Carolina Kymie Vasques Nonaka

    Full Text Available ABSTRACT: Pseudorabies (PR is a highly contagious viral disease of great animal health and economic importance in swine industry. The aim of this study was to evaluate different genomic regions, real-time PCR chemistries and equipment for the molecular diagnosis of PR. Eight primer pairs targeting four genes (gB, gC, gE, gD, three different qPCR chemistries (SybrGreen, hydrolysis probes and plexor and two equipment (ABI7500, Rotorgene 3000 were evaluated. Oligonucleotides targeting gB using hydrolysis probes showed the best performance after evaluating efficiency (99%, the detection limit (10-1.5 TCID50 mL-1 and diagnostic sensitivity and; therefore, those primers were selected for performance verification factors such as repeatability, reproducibility and robustness (1.39% variance between days, 24% variance between analysts and 4.07% variance in analysis error. The qPCR standardized and validated in this research proved to be reliable for the diagnosis of PR and may be used in diagnostic laboratories that follow ISO 17025 and ISO 16140.

  16. Effects of mouthwashes on Knoop hardness and surface roughness of dental composites after different immersion times

    Directory of Open Access Journals (Sweden)

    Diogo de Azevedo Miranda

    2011-04-01

    Full Text Available The aim of this in vitro study was to evaluate the effect of different mouthwashes on superficial roughness and Knoop hardness of two resin composites. Eighty specimens (6 mm Ø and 2 mm height were prepared and divided into eight experimental groups (n = 10 according to the resin composites (4 Seasons and Esthet X, and storage solutions (G1 - Distilled water; G2 - Colgate Plax Overnight; G3 - Colgate Plax Alcohol Free; and G4 - Colgate Plax Whitening. The initial hardness and roughness readings (T1 were measured and then the specimens were stored in 2 mL of mouthwash for 12 h (T2 and 24 h (T3. The data were analyzed with repeat-measures two-way ANOVA and Tukey's test (α = 5%. Regardless of the type of solution and time of exposure, there was no statistical difference for roughness between the resins (p = 0.44. G4 and G8 presented higher roughness means than G1, G3, G5 and G7, after 12 and 24 hours of immersion. For Knoop microhardness analysis, there was a significant reduction for all groups after 12 hours and 24 hours. We conclude that the mouthwashes containing hydrogen peroxide and/or alcohol decrease the microhardness of the resins tested; however, the mouthwash containing hydrogen peroxide had a higher deleterious effect on roughness.

  17. How Cross-Linguistic Differences in the Grammaticalization of Future Time Reference Influence Intertemporal Choices.

    Science.gov (United States)

    Thoma, Dieter; Tytus, Agnieszka E

    2017-08-22

    According to Chen's (2013) Linguistic Savings Hypothesis (LSH), our native language affects our economic behavior. We present three studies investigating how cross-linguistic differences in the grammaticalization of future-time reference (FTR) affect intertemporal choices. In a series of decision scenarios about finance and health issues, we let speakers of altogether five languages that represent FTR with increasing strength, that is, Chinese, German, Danish, Spanish, and English, choose between hypothetical sooner-smaller and later-larger reward options. While the LSH predicts a present-bias that increases with FTR-strength, our decision makers preferred later-larger options and this future-bias increased with FTR-strength. In multiple regressions, the FTR-strength effect persisted when controlled for socioeconomic and cultural differences. We discuss why our findings deviate from the LSH and ask in how far the FTR-strength effect represents a habitual constitution of linguistic relativity or an instance of online decision framing. Copyright © 2017 Cognitive Science Society, Inc.

  18. Trends over time in tree and seedling phylogenetic diversity indicate regional differences in forest biodiversity change.

    Science.gov (United States)

    Potter, Kevin M; Woodall, Christopher W

    2012-03-01

    Changing climate conditions may impact the short-term ability of forest tree species to regenerate in many locations. In the longer term, tree species may be unable to persist in some locations while they become established in new places. Over both time frames, forest tree biodiversity may change in unexpected ways. Using repeated inventory measurements five years apart from more than 7000 forested plots in the eastern United States, we tested three hypotheses: phylogenetic diversity is substantially different from species richness as a measure of biodiversity; forest communities have undergone recent changes in phylogenetic diversity that differ by size class, region, and seed dispersal strategy; and these patterns are consistent with expected early effects of climate change. Specifically, the magnitude of diversity change across broad regions should be greater among seedlings than in trees, should be associated with latitude and elevation, and should be greater among species with high dispersal capacity. Our analyses demonstrated that phylogenetic diversity and species richness are decoupled at small and medium scales and are imperfectly associated at large scales. This suggests that it is appropriate to apply indicators of biodiversity change based on phylogenetic diversity, which account for evolutionary relationships among species and may better represent community functional diversity. Our results also detected broadscale patterns of forest biodiversity change that are consistent with expected early effects of climate change. First, the statistically significant increase over time in seedling diversity in the South suggests that conditions there have become more favorable for the reproduction and dispersal of a wider variety of species, whereas the significant decrease in northern seedling diversity indicates that northern conditions have become less favorable. Second, we found weak correlations between seedling diversity change and latitude in both zones

  19. Changes in transverse relaxation time of quadriceps femoris muscles after active recovery exercises with different intensities.

    Science.gov (United States)

    Mukaimoto, Takahiro; Semba, Syun; Inoue, Yosuke; Ohno, Makoto

    2014-01-01

    The purpose of this study was to examine the changes in the metabolic state of quadriceps femoris muscles using transverse relaxation time (T2), measured by muscle functional magnetic resonance (MR) imaging, after inactive or active recovery exercises with different intensities following high-intensity knee-extension exercise. Eight healthy men performed recovery sessions with four different conditions for 20 min after high-intensity knee-extension exercise on separate days. During the recovery session, the participants conducted a light cycle exercise for 20 min using a cycle (50%, 70% and 100% of the lactate threshold (LT), respectively: active recovery), and inactive recovery. The MR images of quadriceps femoris muscles were taken before the trial and after the recovery session every 30 min for 120 min. The percentage changes in T2 for the rectus femoris and vastus medialis muscles after the recovery session in 50% LT and 70% LT were significantly lower than those in either inactive recovery or 100% LT. There were no significant differences in those for vastus lateralis and vastus intermedius muscles among the four trials. The percentage changes in T2 of rectus femoris and vastus medialis muscles after the recovery session in 50% LT and 70% LT decreased to the values before the trial faster than those in either inactive recovery or 100% LT. Those of vastus lateralis and vastus intermedius muscles after the recovery session in 50% LT and 70% LT decreased to the values before the trial faster than those in 100% LT. Although the changes in T2 after active recovery exercises were not uniform in exercised muscles, the results of this study suggest that active recovery exercise with the intensities below LT are more effective to recover the metabolic state of quadriceps femoris muscles after intense exercise than with either intensity at LT or inactive recovery.

  20. Internalizing versus Externalizing Control: Different Ways to Perform a Time-Based Prospective Memory Task

    Science.gov (United States)

    Huang, Tracy; Loft, Shayne; Humphreys, Michael S.

    2014-01-01

    "Time-based prospective memory" (PM) refers to performing intended actions at a future time. Participants with time-based PM tasks can be slower to perform ongoing tasks (costs) than participants without PM tasks because internal control is required to maintain the PM intention or to make prospective-timing estimates. However, external…

  1. Internalizing versus Externalizing Control: Different Ways to Perform a Time-Based Prospective Memory Task

    Science.gov (United States)

    Huang, Tracy; Loft, Shayne; Humphreys, Michael S.

    2014-01-01

    "Time-based prospective memory" (PM) refers to performing intended actions at a future time. Participants with time-based PM tasks can be slower to perform ongoing tasks (costs) than participants without PM tasks because internal control is required to maintain the PM intention or to make prospective-timing estimates. However, external…

  2. Shear bond strengths of composite resin and giomer to mineral trioxide aggregate at different time intervals.

    Science.gov (United States)

    Ajami, Amir-Ahmad; Bahari, Mahmoud; Hassanpour-Kashani, Arezoo; Abed-Kahnamoui, Mehdi; Savadi-Oskoee, Ayda; Azadi-Oskoee, Farhad

    2017-07-01

    The efficacy of the bond between the restorative materials and the pulp capping materials has an important role in the success of vital pulp therapy. Therefore, the aim of this study was to evaluate the shear bond strength of composite resin and giomer to MTA at different time intervals after mixing of MTA. Ninety cylindrical MTA samples were prepared and assigned to two groups (n=45) based on the restorative materials used (composite resin or giomer). Each group was subdivided into 3 subgroups (n=15) based on the evaluation intervals (immediately, 2.45 hours and 3 days after mixing MTA). After the bonding procedures, the shear bond strengths of the samples were measured in MPa at a strain rate of 0.5 mm/min. Data were analyzed with repeated-measures ANOVA, post hoc tests and t-test (Pcomposite resin was minimum at baseline but it increased significantly 2.45 hours after mixing MTA (P=0.002), with no significant changes in bond strength up to three days (P=0.08). Bond strength of giomer did not exhibit any significant changes from baseline to 2.45 hours after mixing MTA (P=078); however, at 3 days it reached a minimum (P=0.000). In addition, the means of bond strength of composite resin 2.45 hours and 3 days after mixing were significantly higher than those of giomer (P=0.001 and P=0.000, respectively). Bond strengths of composite resin 2.45 hours and also 3 days after mixing were significantly higher than those of giomer. In addition, the shear bond strength of giomer decreased over time; however, the shear bond strength of composite resin increased. Key words:Composite resin, Giomer, Shear bond strength, Vital pulp therapy.

  3. Techno-economic analysis and climate change impacts of sugarcane biorefineries considering different time horizons.

    Science.gov (United States)

    Junqueira, Tassia L; Chagas, Mateus F; Gouveia, Vera L R; Rezende, Mylene C A F; Watanabe, Marcos D B; Jesus, Charles D F; Cavalett, Otavio; Milanez, Artur Y; Bonomi, Antonio

    2017-01-01

    Ethanol production from lignocellulosic feedstocks (also known as 2nd generation or 2G ethanol process) presents a great potential for reducing both ethanol production costs and climate change impacts since agricultural residues and dedicated energy crops are used as feedstock. This study aimed at the quantification of the economic and environmental impacts considering the current and future scenarios of sugarcane biorefineries taking into account not only the improvements of the industrial process but also of biomass production systems. Technology assumptions and scenarios setup were supported by main companies and stakeholders, involved in the lignocellulosic ethanol production chain from Brazil and abroad. For instance, scenarios considered higher efficiencies and lower residence times for pretreatment, enzymatic hydrolysis, and fermentation (including pentoses fermentation); higher sugarcane yields; and introduction of energy cane (a high fiber variety of cane). Ethanol production costs were estimated for different time horizons. In the short term, 2G ethanol presents higher costs compared to 1st generation (1G) ethanol. However, in the long term, 2G ethanol is more competitive, presenting remarkable lower production cost than 1G ethanol, even considering some uncertainties regarding technology and market aspects. In addition, environmental assessment showed that both 1G (in the medium and long term) and 2G ethanol can reduce climate change impacts by more than 80% when compared to gasoline. This work showed the great potential of 2G ethanol production in terms of economic and environmental aspects. These results can support new research programs and public policies designed to stimulate both production and consumption of 2G ethanol in Brazil, accelerating the path along the learning curve. Some examples of mechanisms include: incentives to the establishment of local equipment and enzyme suppliers; and specific funding programs for the development and use of

  4. PCS: an Euler--Lagrange method for treating convection in pulsating stars using finite difference techniques in two spatial dimensions. [Finite difference method, time dependence

    Energy Technology Data Exchange (ETDEWEB)

    Deupree, R.G.

    1977-01-01

    Finite difference techniques were used to examine the coupling of radial pulsation and convection in stellar models having comparable time scales. Numerical procedures are emphasized, including diagnostics to help determine the range of free parameters.

  5. Timing of developmental sequences in different brain structures: physiological and pathological implications.

    Science.gov (United States)

    Dehorter, N; Vinay, L; Hammond, C; Ben-Ari, Y

    2012-06-01

    The developing brain is not a small adult brain. Voltage- and transmitter-gated currents, like network-driven patterns, follow a developmental sequence. Studies initially performed in cortical structures and subsequently in subcortical structures have unravelled a developmental sequence of events in which intrinsic voltage-gated calcium currents are followed by nonsynaptic calcium plateaux and synapse-driven giant depolarising potentials, orchestrated by depolarizing actions of GABA and long-lasting NMDA receptor-mediated currents. The function of these early patterns is to enable heterogeneous neurons to fire and wire together rather than to code specific modalities. However, at some stage, behaviourally relevant activities must replace these immature patterns, implying the presence of programmed stop signals. Here, we show that the developing striatum follows a developmental sequence in which immature patterns are silenced precisely when the pup starts locomotion. This is mediated by a loss of the long-lasting NMDA-NR2C/D receptor-mediated current and the expression of a voltage-gated K(+) current. At the same time, the descending inputs to the spinal cord become fully functional, accompanying a GABA/glycine polarity shift and ending the expression of developmental patterns. Therefore, although the timetable of development differs in different brain structures, the g sequence is quite similar, relying first on nonsynaptic events and then on synaptic oscillations that entrain large neuronal populations. In keeping with the 'neuroarcheology' theory, genetic mutations or environmental insults that perturb these developmental sequences constitute early signatures of developmental disorders. Birth dating developmental disorders thus provides important indicators of the event that triggers the pathological cascade leading ultimately to disease.

  6. Comparison of different real time VOC measurement techniques in a ponderosa pine forest

    Science.gov (United States)

    Kaser, L.; Karl, T.; Schnitzhofer, R.; Graus, M.; Herdlinger-Blatt, I. S.; DiGangi, J. P.; Sive, B.; Turnipseed, A.; Hornbrook, R. S.; Zheng, W.; Flocke, F. M.; Guenther, A.; Keutsch, F. N.; Apel, E.; Hansel, A.

    2013-03-01

    Volatile organic compound (VOC) mixing ratios measured by five independent instruments are compared at a forested site dominated by ponderosa pine (Pinus Ponderosa) during the BEACHON-ROCS field study in summer 2010. The instruments included a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS), a Proton Transfer Reaction Quadrupole Mass Spectrometer (PTR-MS), a Fast Online Gas-Chromatograph coupled to a Mass Spectrometer (GC/MS; TOGA), a Thermal Dissociation Chemical Ionization Mass Spectrometer (PAN-CIMS) and a Fiber Laser-Induced Fluorescence Instrument (FILIF). The species discussed in this comparison include the most important biogenic VOCs and a selected suite of oxygenated VOCs that are thought to dominate the VOC reactivity at this particular site as well as typical anthropogenic VOCs that showed low mixing ratios at this site. Good agreement was observed for methanol, the sum of the oxygenated hemiterpene 2-methyl-3-buten-2-ol (MBO) and the hemiterpene isoprene, acetaldehyde, the sum of acetone and propanal, benzene and the sum of methyl ethyl ketone (MEK) and butanal. Measurements of the above VOCs conducted by different instruments agree within 20%. The ability to differentiate the presence of toluene and cymene by PTR-TOF-MS is tested based on a comparison with GC-MS measurements, suggesting a study-average relative contribution of 74% for toluene and 26% for cymene. Similarly, 2-hydroxy-2-methylpropanal (HMPR) is found to interfere with the sum of methyl vinyl ketone and methacrolein (MVK + MAC) using PTR-(TOF)-MS at this site. A study-average relative contribution of 85% for MVK + MAC and 15% for HMPR was determined. The sum of monoterpenes measured by PTR-MS and PTR-TOF-MS was generally 20-25% higher than the sum of speciated monoterpenes measured by TOGA, which included α-pinene, β-pinene, camphene, carene, myrcene, limonene, cineole as well as other terpenes. However, this difference is consistent throughout the study, and

  7. Comparison of different real time VOC measurement techniques in a ponderosa pine forest

    Directory of Open Access Journals (Sweden)

    L. Kaser

    2012-10-01

    Full Text Available Volatile organic compound (VOC mixing ratios measured by five independent instruments are compared at a forested site dominated by ponderosa pine (Pinus Ponderosa during the BEACHON-ROCS field study in summer 2010. The instruments included a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS, a Proton Transfer Reaction Quadrupole Mass Spectrometer (PTR-MS, a Fast Online Gas-Chromatograph coupled to a Mass Spectrometer (GC/MS; TOGA, a Thermal Dissociation Chemical Ionization Mass Spectrometer (PAN-CIMS and a Fiber Laser-Induced Fluorescence Instrument (FILIF. The species discussed in this comparison include the most important biogenic VOCs and a selected suite of oxygenated VOCs that are thought to dominate the VOC reactivity at this particular site as well as typical anthropogenic VOCs that showed low mixing ratios at this site. Good agreement was observed for methanol, the sum of the oxygenated hemiterpene 2-methyl-3-buten-2-ol (MBO and the hemiterpene isoprene, acetaldehyde, the sum of acetone and propanal, benzene and the sum of methyl ethyl ketone (MEK and butanal. Measurements of the above VOCs conducted by different instruments agree within 20%. The ability to differentiate the presence of toluene and cymene by PTR-TOF-MS is tested based on a comparison with GC-MS measurements, suggesting a study-average relative contribution of 74% for toluene and 26% for cymene. Similarly, 2-hydroxy-2-methylpropanal (HMPR is found to interfere with the sum of methyl vinyl ketone and methacrolein (MVK+MAC using PTR-(TOF-MS at this site. A study-average relative contribution of 85% for MVK+MAC and 15% for HMPR was determined. The sum of monoterpenes measured by PTR-MS and PTR-TOF-MS was generally 20–25% higher than the sum of speciated monoterpenes measured by TOGA, which included α-pinene, β-pinene, camphene, carene, myrcene, limonene, cineole as well as other terpenes. However, this difference is consistent throughout the

  8. Comparison of different real time VOC measurement techniques in a ponderosa pine forest

    Directory of Open Access Journals (Sweden)

    L. Kaser

    2013-03-01

    Full Text Available Volatile organic compound (VOC mixing ratios measured by five independent instruments are compared at a forested site dominated by ponderosa pine (Pinus Ponderosa during the BEACHON-ROCS field study in summer 2010. The instruments included a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS, a Proton Transfer Reaction Quadrupole Mass Spectrometer (PTR-MS, a Fast Online Gas-Chromatograph coupled to a Mass Spectrometer (GC/MS; TOGA, a Thermal Dissociation Chemical Ionization Mass Spectrometer (PAN-CIMS and a Fiber Laser-Induced Fluorescence Instrument (FILIF. The species discussed in this comparison include the most important biogenic VOCs and a selected suite of oxygenated VOCs that are thought to dominate the VOC reactivity at this particular site as well as typical anthropogenic VOCs that showed low mixing ratios at this site. Good agreement was observed for methanol, the sum of the oxygenated hemiterpene 2-methyl-3-buten-2-ol (MBO and the hemiterpene isoprene, acetaldehyde, the sum of acetone and propanal, benzene and the sum of methyl ethyl ketone (MEK and butanal. Measurements of the above VOCs conducted by different instruments agree within 20%. The ability to differentiate the presence of toluene and cymene by PTR-TOF-MS is tested based on a comparison with GC-MS measurements, suggesting a study-average relative contribution of 74% for toluene and 26% for cymene. Similarly, 2-hydroxy-2-methylpropanal (HMPR is found to interfere with the sum of methyl vinyl ketone and methacrolein (MVK + MAC using PTR-(TOF-MS at this site. A study-average relative contribution of 85% for MVK + MAC and 15% for HMPR was determined. The sum of monoterpenes measured by PTR-MS and PTR-TOF-MS was generally 20–25% higher than the sum of speciated monoterpenes measured by TOGA, which included α-pinene, β-pinene, camphene, carene, myrcene, limonene, cineole as well as other terpenes. However, this difference is consistent throughout the study

  9. Renal Toxicity of Mercuric Chloride at Different Time Intervals in Rats

    Directory of Open Access Journals (Sweden)

    W.A. Al-Madani

    2009-01-01

    Full Text Available This study was undertaken to study the renal toxicity of mercuric chloride in rats at different periods of time. The following groups of rats were studied: i control, ii placebo, iii rats injected with a single ip dose of 100 mg/kg body weight of 2, 3 dimercapto- 1-propanesulfonic acid, iv rats injected with a single ip dose of 100 mg/kg body weight of 2, 3 dimercapto-1-propanesulfonic acid (DMPS followed by a single dose ip of 2.0 mg HgCl2/kg body weight one hour after DMPS injection v rats injected with a single ip dose of 2.0 mg HgCl2/kg body weight. Results indicate that mercuric chloride was more toxic after 48 hours of its administration when compared to 24 hours. Mercuric chloride administration caused an impairment of renal function which was evident from a significant decrease in urine volume, urinary excretion of urea, creatinine and glomerular filteration rate (P < 0.001 when compared to other treated groups. There was an increased excretion of protein, albumin and γ—glutamyltransferase in the urine of mercuric chloride treated rats. Administration of 2, 3 dimercapto-1-propanesulfonic acid before mercuric chloride treatment caused the altered indices to return to near normal levels.

  10. Germanium nanoparticles grown at different deposition times for memory device applications

    Energy Technology Data Exchange (ETDEWEB)

    Mederos, M., E-mail: melissa.mederos@gmail.com [Center for Semiconductor Components and Nanotechnology (CCSNano), University of Campinas (Unicamp), Rua João Pandia Calógeras 90, Campinas, CEP: 13083-870, São Paulo (Brazil); Mestanza, S.N.M. [Federal University of ABC (UFABC), Rua Santa Adélia 166, Bangu, Santo André, CEP: 09210-170, São Paulo (Brazil); Lang, R. [Institute of Science and Technology, Federal University of São Paulo (UNIFESP), Rua Talim, 330, São José dos Campos, CEP: 12231-280, São Paulo (Brazil); Doi, I.; Diniz, J.A. [Center for Semiconductor Components and Nanotechnology (CCSNano), University of Campinas (Unicamp), Rua João Pandia Calógeras 90, Campinas, CEP: 13083-870, São Paulo (Brazil); School of Electrical and Computer Engineering, University of Campinas (Unicamp), Av. Albert Einstein 400, Campinas, CEP: 13083-852, São Paulo (Brazil)

    2016-07-29

    In the present work, circular Metal-Oxide-Semiconductor capacitors with 200 μm of diameter and germanium (Ge) nanoparticles (NPs) embedded in the gate oxide are studied for memory applications. Optimal process parameters are investigated for Ge NPs growing by low pressure chemical vapor deposition at different deposition times. Photoluminescence measurements showed room-temperature size-dependent green-red region bands attributed to quantum confinement effects present in the NPs. High-frequency capacitance versus voltage measurements demonstrated the memory effects on the MOS structures due to the presence of Ge NPs in the gate oxide acting as discrete floating gates. Current versus voltage measurements confirmed the Fowler-Nordheim tunneling as the programming mechanism of the devices. - Highlights: • Ge nanoparticles with high density and uniforms sizes were obtained by LPCVD. • Room-temperature size-dependent bands of photoluminescence were observed. • MOS capacitors with Ge nanoparticles embedded in the oxide were fabricated. • Ge nanoparticles are the main responsible for the memory properties in the devices. • Fowler-Nordheim tunneling is the conduction mechanism observed on the devices.

  11. Finite difference time domain model of ultrasound propagation in agarose scaffold containing collagen or chondrocytes.

    Science.gov (United States)

    Inkinen, Satu I; Liukkonen, Jukka; Malo, Markus K H; Virén, Tuomas; Jurvelin, Jukka S; Töyräs, Juha

    2016-07-01

    Measurement of ultrasound backscattering is a promising diagnostic technique for arthroscopic evaluation of articular cartilage. However, contribution of collagen and chondrocytes on ultrasound backscattering and speed of sound in cartilage is not fully understood and is experimentally difficult to study. Agarose hydrogels have been used in tissue engineering applications of cartilage. Therefore, the aim of this study was to simulate the propagation of high frequency ultrasound (40 MHz) in agarose scaffolds with varying concentrations of chondrocytes (1 to 32 × 10(6) cells/ml) and collagen (1.56-200 mg/ml) using transversely isotropic two-dimensional finite difference time domain method (FDTD). Backscatter and speed of sound were evaluated from the simulated pulse-echo and through transmission measurements, respectively. Ultrasound backscatter increased with increasing collagen and chondrocyte concentrations. Furthermore, speed of sound increased with increasing collagen concentration. However, this was not observed with increasing chondrocyte concentrations. The present study suggests that the FDTD method may have some applicability in simulations of ultrasound scattering and propagation in constructs containing collagen and chondrocytes. Findings of this study indicate the significant role of collagen and chondrocytes as ultrasound scatterers and can aid in development of modeling approaches for understanding how cartilage architecture affects to the propagation of high frequency ultrasound.

  12. Devulcanization of ground tire rubber: Physical and chemical changes after different microwave exposure times

    Directory of Open Access Journals (Sweden)

    P. S. Garcia

    2015-11-01

    Full Text Available Microwave devulcanization is known to be a promising and an efficient rubber recycling method which makes possible for the rubber to regain its fluidity, and makes it capable of being remolded and revulcanized. The focus of this work is to understand the physical and chemical changes that occur in the ground tire rubber after different microwave exposure periods. For this purpose chemical, thermal, rheological and morphological analyses were performed on the tire rubber, which contains natural rubber (NR and styrene-butadiene rubber (SBR as polymeric material. The results showed that the microwave treatment promoted the breaking of sulfur cross-links and consequently increased the rubber fluidity. However, long periods of exposure led to degradation and modification of some properties. At nanoscale, the deformation of the devulcanized NR domain under stress was observed, and the morphology obtained appears to be a droplet dispersion morphology. The most exposed samples presented only one glass transition temperature, and from this it was concluded that the treatment may have played an important role in the compatibilization of the elastomeric blend. Based on the results, it is required to control the microwave exposure time and polymeric degradation in order to achieve a regenerated rubber with satisfactory properties.

  13. Three-dimensional Sound Source Localization Using Inter-channel Time Difference Trajectory

    Directory of Open Access Journals (Sweden)

    Sangmoon Lee

    2015-12-01

    Full Text Available Sound source localization is one of the basic and essential techniques for intelligent robots in terms of human-robot interaction and has been utilized in various engineering fields. This paper suggests a new localization method using an inter-channel time difference trajectory, which is a new localization cue for efficient 3-D localization. As one of the ways to realize the proposed cue, a two-channel rotating array is employed. Two microphones are attached on the left and right sides of the spherical head. One microphone is in a circular motion on the right side, while the other is fixed on the left side. According to the rotating motion of the array, the (source direction-dependent characteristics of the trajectories are analysed using the Ray-Tracing formula extended for 3-D models. In simulation, the synthesized signals generated by the fixed and rotating microphone signal models were used as the output signals of the two microphones. The simulation showed that the localization performance is strongly dependent on the azimuthal position of a source, which is caused by the asymmetry of the trajectory amplitude. Additionally, the experimental results of the two experiments carried out in the room environment demonstrated that the proposed system can localize a Gaussian noise source and a voice source in 3-D space.

  14. Transfer-matrix approach for finite-difference time-domain simulation of periodic structures.

    Science.gov (United States)

    Deinega, Alexei; Belousov, Sergei; Valuev, Ilya

    2013-11-01

    Optical properties of periodic structures can be calculated using the transfer-matrix approach, which establishes a relation between amplitudes of the wave incident on a structure with transmitted or reflected waves. The transfer matrix can be used to obtain transmittance and reflectance spectra of finite periodic structures as well as eigenmodes of infinite structures. Traditionally, calculation of the transfer matrix is performed in the frequency domain and involves linear algebra. In this work, we present a technique for calculation of the transfer matrix using the finite-difference time-domain (FDTD) method and show the way of its implementation in FDTD code. To illustrate the performance of our technique we calculate the transmittance spectra for opal photonic crystal slabs consisting of multiple layers of spherical scatterers. Our technique can be used for photonic band structure calculations. It can also be combined with existing FDTD methods for the analysis of periodic structures at an oblique incidence, as well as for modeling point sources in a periodic environment.

  15. Different Approaches for Moller's Energy in the Kasner-type Space-time

    CERN Document Server

    Salti, M

    2005-01-01

    Considering the Moller energy definition in both Einstein's theory of general relativity and tele-parallel theory of gravity, we find the energy of the universe based on viscous Kasner-type metrics. The energy distribution which includes both the matter and gravitational field is found to be zero in both of these different gravitation theories and this result agrees with previous works of Cooperstock and Israelit, Rosen, Johri et al., Banerjee-Sen, Vargas who investigated the problem of the energy in Friedmann-Robertson-Walker universe in Einstein's theory of general relativity and Aydogdu-Salti who considered the same problem in tele-parallel gravity. In all of these works, they found that the energy of the Friedmann-Robertson-Walker space-time is zero. Our result is the same as obtained in the studies of Salti and Havare. They used the viscous Kasner-type metric and found total energy and momentum by using Bergmann-Thomson energy-momentum formulation in both general relativity and tele-parallel gravity. The...

  16. Experimental Study of the Recovery Times of Spark Gap Switch with Different Gases

    Institute of Scientific and Technical Information of China (English)

    YIN Yi; LIU Jinliang; ZHONG Huihuang; FENG Jiahuai

    2008-01-01

    A two-pulse method is used to determine the insulation recovery time of the gas spark gap switch with different types of gas applied in a high power accelerator with a water dielectric pulse forming line. At the breakdown voltage of 450 kV, with the vacuum diode voltage of about 200 kV, and a current of 30 kA, recovery characteristics of H2, N2, SF6 were studied. The recovery percentages of the gas breakdown voltage and vacuum diode voltage were determined. The results show that hydrogen has the best recovery characteristics. At a pulse interval of 8.8 ms, the recovery percentages of both the gas breakdown voltage and vacuum diode voltage for hydrogen exceed 95%. For SF6 and N2 with an interval of 25 ms and 50 ms respectively, a 90% voltage recovery was obtained. The experiments also proved that the repetitive rate of the high power accelerator with a pulse forming line is mainly restricted by the gas switch repetitive rate; the recovery percentages of the vacuum diode voltage are limited by the recovery percentages of the gas switch breakdown voltage. The hydrogen switch can be employed for a high repetitive rate-high power accelerator with a pulse forming line.

  17. Individual variation in habituation: behaviour over time toward different stimuli in threespine sticklebacks (Gasterosteus aculeatus)

    Science.gov (United States)

    Bell, Alison M.; Peeke, Harman V.S.

    2014-01-01

    Habituation, or the relatively permanent waning of a response as a result of repeated stimulation, is a form of behavioural plasticity that allows animals to filter out irrelevant stimuli and to focus selectively on important stimuli. Individuals that fail to habituate might be at a disadvantage if they continue to respond to irrelevant stimuli; therefore, habituation can have adaptive significance. In this study we compared rates of behaviour over time toward three different ecologically-relevant stimuli (food, a male intruder and a gravid female) in threespine sticklebacks (Gasterosteus aculeatus). We detected evidence for habituation to the stimuli, and males in this study were especially aggressive toward both male and female conspecifics. Although there were some clear temporal patterns that could be detected by looking at average behaviour, not all individuals behaved in the same ‘average’ way. We detected substantial inter-individual variation in behaviour toward all three stimuli, inter-individual variation in rates of habituation to both male and female conspecifics, but no evidence for correlations between behaviours across stimuli (behavioural syndromes). These results suggest that individual animals vary in rates of habituation, and prompt hypotheses about the causes and consequences of variation in rates of habituation. PMID:25678715

  18. Histological, histomorphometric and microtomographic analyses of retrieval hip resurfacing arthroplasty failed at different times

    Directory of Open Access Journals (Sweden)

    Salamanna Francesca

    2013-01-01

    Full Text Available Abstract Background Metal-on-metal hip resurfacing arthroplasty (HR has been gaining popularity especially for young and active patients. Although different series report good mid-term results, the long-term outcome and failure mechanisms are still concerning. In this consecutive revision case series, 9 retrieved specimens of a failed Birmingham Hip Resurfacing (BHR were divided according to the time to fracture: 3 specimens failed at less than 6 months (Group 1, 3 failed between 6 months and 3 years (Group 2 and 3 failed later than 3 years (Group 3. The objective of the study was to examine by a specific quantitative histomorphometry and microtomography (micro-CT method the characteristics of bone quality and its microarchitecture in retrieved metal-on-metal HR. Methods A series of 948 BHR were performed between 2001 and 2009. Among these implants 10 failures occurred and nine of these underwent revision surgery and were examined by histomorphometry and micro-CT. Results Histomorphometry showed a significant increase in trabecular separation (Tb.Sp in Group 3 in comparison with Group 1 (113%, p  Conclusions This study showed that the morphometric parameters considered are crucial for a good understanding of mechanical properties of HR and may be of significant importance in the pathogenesis of HR failure particularly in the development of late fractures.

  19. Gender Differences Time Trends for Metabolic Syndrome and Its Components among Tehranian Children and Adolescents

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    Maryam Barzin

    2012-01-01

    Full Text Available Aims. To investigate the trend of metabolic syndrome and its components in Tehran children and adolescents during a median followup of 6.6 years. Methods. Data from 1999–2001 (phase I, 2002–2005 (phase II, and 2006–2008 (phase III of the Tehran, Lipid and Glucose Study were analyzed (=5439; age 6–18 years for the trend of metabolic syndrome (MetS and its components. General estimation equation (GEE models were used to analyze this correlated data. Results. The crude prevalence of MetS for boys at baseline was 13.2%, which increased to 16.4% in the third phase. In girls, the prevalence of Mets decreased from 11.8% at baseline to 6% during followup. The odd ratios (OR of obesity over the whole study period were raised in both sexes. The OR of abdominal obesity increased significantly in boys, but no change was observed in girls. No significant OR was observed in boys, while OR for MetS was shown to have a decreasing trend in girls during the followup. In the three time points, the ORs of MetS decreased significantly in girls but no significant difference was observed in boys. Conclusion. Inspite of increasing trend for obesity in both sexes, the trend of MetS decreased in girls and was relatively stable in boys, in Tehranian children, and adolescents.

  20. Relations between Adolescents' Self-Evaluations, Time Perspectives, Motivation for School and Their Achievement in Different Countries and at Different Ages

    Science.gov (United States)

    Peetsma, Thea; Hascher, Tina; van der Veen, Ineke; Roede, Ewoud

    2005-01-01

    The present study focused on the relations between the self-efficacy, social self-concept, time perspectives, school investment and academic achievement of students in four different European countries and in different adolescence periods. A total of 1623 students completed questionnaires. The relations between the concepts proved not to be…