387 research outputs found

    Test-Retest Reliability of the SWAY Balance Mobile Application

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    The SWAY Balance Mobile Application is an FDA-cleared balance testing system which uses the built-in tri-axial accelerometers of a mobile electronic device to objectively assess postural movement. The system was designed to provide a means of quantitative balance assessment in clinical and on-field environments. The purpose of this study was to determine the intrasession and intersession reliability, as well as the minimum difference to be considered real, of the SWAY Balance Mobile Application

    Artemis Curation: Preparing for Sample Return from the Lunar South Pole

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    Space Policy Directive-1 mandates that the United States will lead the return of humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations. In addition, the Vice President stated that It is the stated policy of this administration and the United States of America to return American astronauts to the Moon within the next five years, that is, by 2024. These efforts, under the umbrella of the recently formed Artemis Program, include such historic goals as the flight of the first woman to the Moon and the exploration of the lunar south-polar region. Among the top priorities of the Artemis Program is the return of a suite of geologic samples, providing new and significant opportunities for progressing lunar science and human exploration. In particular, successful sample return is necessary for understanding the history of volatiles in the Solar System and the evolution of the Earth-Moon system, fully constraining the hazards of the lunar polar environment for astronauts, and providing the necessary data for constraining the abundance and distribution of resources for in-situ resource utilization (ISRU). Here we summarize the ef-forts of the Astromaterials Acquisition and Curation Office (hereafter referred to as the Curation Office) to ensure the success of Artemis sample return (per NASA Policy Directive (NPD) 7100.10E)

    Particle trajectories in linearized irrotational shallow water flows

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    We investigate the particle trajectories in an irrotational shallow water flow over a flat bed as periodic waves propagate on the water's free surface. Within the linear water wave theory, we show that there are no closed orbits for the water particles beneath the irrotational shallow water waves. Depending on the strength of underlying uniform current, we obtain that some particle trajectories are undulating path to the right or to the left, some are looping curves with a drift to the right and others are parabolic curves or curves which have only one loop

    Patterns of Sexual Arousal in Young, Heterosexual Men Who Experience Condom-Associated Erection Problems (CAEP)

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    Introduction Condom-associated erection problems (CAEP) are reported by a substantial number of young men and are associated with inconsistent and/or incomplete condom use. The underlying mechanisms of CAEP are not well understood and research examining the possibility that men who report CAEP differ from other men in their sexual responsivity is lacking. Aim This study used psychophysiological methods to examine whether men who report CAEP have a higher threshold for sexual arousal, a stronger need for tactile stimulation, and/or more easily lose their sexual arousal due to neutral distractors or performance-related demands. Methods A total of 142 young, heterosexual men (53% reporting CAEP) were presented with four 3-minute erotic film clips. Three film clips were combined with one of the following manipulations: 1) distraction, 2) performance demand, or 3) vibrotactile stimulation. One erotic film clip was presented with no further instructions or manipulations. Main Outcome Measures Average penile circumference changes during the first, second, and third minute (Time) of the erotic film stimuli (Condition) were submitted to a mixed-model ANOVA with Condition and Time as within-subjects factors and Group (CAEP/No-CAEP) as between-subjects factor. Results Significant main effects of Condition and Time and a significant interaction of Group×Time were found. No significant interactions involving Condition were found. Men who reported CAEP had smaller erectile responses during the first minute, regardless of film condition, than men who reported no CAEP (F(1,141)=8.64, p<.005). Conclusion The findings suggest that men with and without CAEP differ in the ease with which they become sexually aroused. Men reporting CAEP needed more time and/or more intense stimulation to become aroused. To our knowledge, this study is the first to use psychophysiological methods to assess sexual responsivity in men who report CAEP

    Does the timing and duration of mental health problems during childhood and adolescence matter for labour market participation of young adults?

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    BACKGROUND: Little is known about the timing and duration of mental health problems (MHPs) on young adults’ labour market participation (LMP). This life-course study aims to examine whether and how the timing and duration of MHPs between childhood and young adulthood are associated with LMP in young adulthood. METHODS: Logistic regression analyses were performed with data from the Tracking Adolescents’ Individual Lives Survey (TRAILS), a Dutch prospective cohort study with 15-year follow-up (N=874). Internalising and externalising problems were measured by the Youth/Adult Self-Report at ages 11, 13, 16, 19 and 22. Labour market participation (having a paid job yes/no) was assessed at age 26. RESULTS: Internalising problems at all ages and externalising problems at age 13, 19 and 22 were associated with an increased risk of not having a paid job (internalising problems ORs ranging from 2.24, 95% CI 1.02 to 4.90 at age 11 to OR 6.58, CI 3.14 to 13.80 at age 22; externalising problems ORs from 2.84, CI 1.11 to 7.27 at age 13 to OR 6.36, CI 2.30 to 17.56 at age 22). Especially a long duration of internalising problems increased the risk of not having a paid job in young adulthood. CONCLUSION: The duration of MHPs during childhood and adolescence is strongly associated with not having paid work in young adulthood. This emphasises the necessity of applying a life-course perspective when investigating the effect of MHPs on LMP. Early monitoring, mental healthcare and the (early) provision of employment support may improve young adult’s participation in the labour market

    A rigorous implementation of the Jeans--Landau--Teller approximation

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    Rigorous bounds on the rate of energy exchanges between vibrational and translational degrees of freedom are established in simple classical models of diatomic molecules. The results are in agreement with an elementary approximation introduced by Landau and Teller. The method is perturbative theory ``beyond all orders'', with diagrammatic techniques (tree expansions) to organize and manipulate terms, and look for compensations, like in recent studies on KAM theorem homoclinic splitting.Comment: 23 pages, postscrip

    Steady water waves with multiple critical layers: interior dynamics

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    We study small-amplitude steady water waves with multiple critical layers. Those are rotational two-dimensional gravity-waves propagating over a perfect fluid of finite depth. It is found that arbitrarily many critical layers with cat's-eye vortices are possible, with different structure at different levels within the fluid. The corresponding vorticity depends linearly on the stream function.Comment: 14 pages, 3 figures. As accepted for publication in J. Math. Fluid Mec

    On the particle paths and the stagnation points in small-amplitude deep-water waves

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    In order to obtain quite precise information about the shape of the particle paths below small-amplitude gravity waves travelling on irrotational deep water, analytic solutions of the nonlinear differential equation system describing the particle motion are provided. All these solutions are not closed curves. Some particle trajectories are peakon-like, others can be expressed with the aid of the Jacobi elliptic functions or with the aid of the hyperelliptic functions. Remarks on the stagnation points of the small-amplitude irrotational deep-water waves are also made.Comment: to appear in J. Math. Fluid Mech. arXiv admin note: text overlap with arXiv:1106.382

    Uniqueness and Nondegeneracy of Ground States for (−Δ)sQ+Q−Qα+1=0(-\Delta)^s Q + Q - Q^{\alpha+1} = 0 in R\mathbb{R}

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    We prove uniqueness of ground state solutions Q=Q(∣x∣)≥0Q = Q(|x|) \geq 0 for the nonlinear equation (−Δ)sQ+Q−Qα+1=0(-\Delta)^s Q + Q - Q^{\alpha+1}= 0 in R\mathbb{R}, where 0<s<10 < s < 1 and 0<α<4s1−2s0 < \alpha < \frac{4s}{1-2s} for s<1/2s < 1/2 and 0<α<∞0 < \alpha < \infty for s≥1/2s \geq 1/2. Here (−Δ)s(-\Delta)^s denotes the fractional Laplacian in one dimension. In particular, we generalize (by completely different techniques) the specific uniqueness result obtained by Amick and Toland for s=1/2s=1/2 and α=1\alpha=1 in [Acta Math., \textbf{167} (1991), 107--126]. As a technical key result in this paper, we show that the associated linearized operator L+=(−Δ)s+1−(α+1)QαL_+ = (-\Delta)^s + 1 - (\alpha+1) Q^\alpha is nondegenerate; i.\,e., its kernel satisfies ker L+=span {Q′}\mathrm{ker}\, L_+ = \mathrm{span}\, \{Q'\}. This result about L+L_+ proves a spectral assumption, which plays a central role for the stability of solitary waves and blowup analysis for nonlinear dispersive PDEs with fractional Laplacians, such as the generalized Benjamin-Ono (BO) and Benjamin-Bona-Mahony (BBM) water wave equations.Comment: 45 page
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