2,696 research outputs found

    The Effect of Alpha Brain-Wave Control on the Speech of Two Adult Stutterers

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    The purpose of this study was to examine, compare and describe the effect of alpha brain-wave conditioning upon the speech of two adult stutterers. Five sessions of baserate measurement were followed by a sequence of conditioning sessions (in which an electronic brain-wave monitor was used to train subjects to control their alpha rhythms), after which the speech of the stutterers was re-evaluated by a procedure which was identical to the baserate procedure. The four speech activities which were investigated were: reading without feedback of alpha-band brain activity from the monitor, monologue without feedback from the monitor, reading with feedback from the monitor, and monologue with feedback from the monitor. Subject I displayed a significant decrease in the number of stuttered words and severity ratings in monologue without feedback from the monitor when the re-evaluation measures were compared with baserate measures. Number of stuttered words and severity ratings were not significantly affected in the three other speech activities for Subject I. However, Subject II exhibited a significant increase in the number of stuttered words in both unmonitored and monitored reading samples when the re-evaluation measures were compared with baserate. Severity ratings were not significantly affected in either unmonitored or monitored reading samples. There were also no significant differences between baserate and re-evaluation measures of number of stuttered words and severity in either unmonitored or monitored monologues for Subject II. This procedure showed that a significant relationship exists between the number of stuttered words and the combined effect of session number, total time for reading sample, duration of alpha rhythm, severity rating of stuttering, and control of alpha rhythm in monitored reading samples for both subjects. There was no significant relationship, however, between severity rating and the combined effect of session number, total time for reading sample, duration of alpha rhythm, severity rating of stuttering, and control of alpha rhythm in monitored reading samples for either subject. There were also no significant relationships among the variables for the monitored monologue speech activity for either subject

    Cavity-enhanced optical frequency comb spectroscopy in the mid-infrared - application to trace detection of H2O2

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    We demonstrate the first cavity-enhanced optical frequency comb spectroscopy in the mid-infrared wavelength region and report the sensitive real-time trace detection of hydrogen peroxide in the presence of a large amount of water. The experimental apparatus is based on a mid-infrared optical parametric oscillator synchronously pumped by a high power Yb:fiber laser, a high finesse broadband cavity, and a fast-scanning Fourier transform spectrometer with autobalancing detection. The comb spectrum with a bandwidth of 200 nm centered around 3.75 {\mu}m is simultaneously coupled to the cavity and both degrees of freedom of the comb, i.e., the repetition rate and carrier envelope offset frequency, are locked to the cavity to ensure stable transmission. The autobalancing detection scheme reduces the intensity noise by a factor of 300, and a sensitivity of 5.4 {\times} 10^-9 cm^-1 Hz^-1/2 with a resolution of 800 MHz is achieved (corresponding to 6.9 {\times} 10^-11 cm^-1 Hz^-1/2 per spectral element for 6000 resolved elements). This yields a noise equivalent detection limit for hydrogen peroxide of 8 parts-per-billion (ppb); in the presence of 2.8% of water the detection limit is 130 ppb. Spectra of acetylene, methane and nitrous oxide at atmospheric pressure are also presented, and a line shape model is developed to simulate the experimental data.Comment: submitted to special FLAIR 2011 issue of Appl. Phys.

    Discrete phase-space structure of nn-qubit mutually unbiased bases

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    We work out the phase-space structure for a system of nn qubits. We replace the field of real numbers that label the axes of the continuous phase space by the finite field \Gal{2^n} and investigate the geometrical structures compatible with the notion of unbiasedness. These consist of bundles of discrete curves intersecting only at the origin and satisfying certain additional properties. We provide a simple classification of such curves and study in detail the four- and eight-dimensional cases, analyzing also the effect of local transformations. In this way, we provide a comprehensive phase-space approach to the construction of mutually unbiased bases for nn qubits.Comment: Title changed. Improved version. Accepted for publication in Annals of Physic

    The relationship between mental toughness and cognitive control: evidence from the item-method directed forgetting task

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    Previous research by the authors found that mental toughness, as measured by the Mental Toughness Questionnaire 48 (MTQ48; Clough, P.J., Earle, K., & Sewell, D. [2002]. Mental toughness: the concept and its measurement. In I. Cockerill (Ed.), Solutions in sport psychology [pp. 32–43]. London: Thomson Publishing), was significantly associated with performance on the list-method directed forgetting task. The current study extends this finding to the item-method directed forgetting task in which the instruction to Remember or Forget is given after each item in the study list. A significant positive association was found between the correct recognition of Remember words and the emotional control subscale of the MTQ48. No significant associations were observed with other measures of mental toughness or personality. The findings are discussed in terms of the relationship between mental toughness and cognitive control

    Hedging in Field Theory Models of the Term Structure

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    We use path integrals to calculate hedge parameters and efficacy of hedging in a quantum field theory generalization of the Heath, Jarrow and Morton (HJM) term structure model which parsimoniously describes the evolution of imperfectly correlated forward rates. We also calculate, within the model specification, the effectiveness of hedging over finite periods of time. We use empirical estimates for the parameters of the model to show that a low dimensional hedge portfolio is quite effective.Comment: 18 figures, Invited Talk, International Econophysics Conference, Bali, 28-31 August 200

    Direct measurements of DOCO isomers in the kinetics of OD+CO

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    Quantitative and mechanistically-detailed kinetics of the reaction of hydroxyl radical (OH) with carbon monoxide (CO) have been a longstanding goal of contemporary chemical kinetics. This fundamental prototype reaction plays an important role in atmospheric and combustion chemistry, motivating studies for accurate determination of the reaction rate coefficient and its pressure and temperature dependence at thermal reaction conditions. This intricate dependence can be traced directly to details of the underlying dynamics (formation, isomerization, and dissociation) involving the reactive intermediates cis- and trans-HOCO, which can only be observed transiently. Using time-resolved frequency comb spectroscopy, comprehensive mechanistic elucidation of the kinetics of the isotopic analogue deuteroxyl radical (OD) with CO has been realized. By monitoring the concentrations of reactants, intermediates, and products in real-time, the branching and isomerization kinetics and absolute yields of all species in the OD+CO reaction are quantified as a function of pressure and collision partner.Comment: 19 pages, 4 figure

    Alfalfa Yields from Mixtures of Dormant and Non-dormant Varieties

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    During the establishment year, alfalfa seedings typically yield only 40-60% of fully established stands. All alfalfa varieties grown in Iowa are classified as dormant or moderately dormant, a characteristic that is important for winter survival. However, as plants become dormant in late summer, their yield declines. Alfalfa varieties from the southwestern United States are non-dormant and continue to grow until the autumn freeze, but tend to die over winter. The objective of this experiment was to determine if including a proportion of non-dormant seed at planting could improve establishment year yield without affecting successive year yields or forage quality. The rationale for this experiment is that more plants are present in the first year of a stand than in successive years when individual plants grow larger as their crowns expand. Because of normal plant loss, we reasoned that death of non-dormant plants after the first winter might not adversely affect the yields of the remaining stand
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