BELAY TECHNIQUES ON STOP FALLING OF A CLIMBER

The purpose of the present study was to identify the kinematic differences between two popular rock climbing belay techniques used in the United States: brake, under, slide (BUS) and slip, slap, slide (SSS) and their efficiency in stopping the fall of a climber. Five male subjects with no previous belaying experience from two different beginning rock climbing classes were recruited to participate in the study (n = 10). Each subject passed a practical belay test before participating in the study. Data of time to stop the fall of a climber, vertical displacement of the falling climber, maximum negative vertical velocity of the falling climber, and percentage of time each belayer was in the braked position were collected. Results showed that the climber had significant greater falling displacement, longer time to stop, and higher maximum negative velocity when SSS was performed

The Stokes conjecture for waves with vorticity

We study stagnation points of two-dimensional steady gravity free-surface water waves with vorticity. We obtain for example that, in the case where the free surface is an injective curve, the asymptotics at any stagnation point is given either by the “Stokes corner flow” where the free surface has a corner of 120°, or the free surface ends in a horizontal cusp, or the free surface is horizontally flat at the stagnation point. The cusp case is a new feature in the case with vorticity, and it is not possible in the absence of vorticity. In a second main result we exclude horizontally flat singularities in the case that the vorticity is 0 on the free surface. Here the vorticity may have infinitely many sign changes accumulating at the free surface, which makes this case particularly difficult and explains why it has been almost untouched by research so far. Our results are based on calculations in the original variables and do not rely on structural assumptions needed in previous results such as isolated singularities, symmetry and monotonicity

Work functioning of Dutch workers with a chronic disease in early, mid and late working life:Cross-sectional findings from 38,470 participants in the Lifelines Cohort Study

Insight into the work functioning of workers with chronic diseases may help to improve their sustainable employability. This study examines the work functioning of workers with cardiovascular disease (CVD), diabetes mellitus type 2 (DM2), chronic obstructive pulmonary disease (COPD), rheumatoid arthritis and depression across early, mid, and late working life. This cross-sectional study used data from 38,470 participants of the Dutch Lifelines study. Chronic diseases were classified based on clinical measures, self-reports, and medication. Work functioning was measured with the Work Role Functioning Questionnaire (WRFQ), covering work scheduling and output demands, physical demands, mental and social demands, and flexibility demands. Multivariable linear and logistic regression analyses were used to examine associations between chronic diseases and work functioning (continuous) and low work functioning (dichotomous). Depression was associated with lower work functioning across all subscales and working life stages, with the lowest score in the work scheduling and output demands subscale in late working life (B:-9.51;95%CI:-11.4,-7.65). Rheumatoid arthritis was most strongly associated with lower work functioning in the physical demands subscale, with the lowest score in early working life (B:-9.97;95%CI:-19.0,-0.89). Associations between CVD and DM2 and work functioning were absent in early working life but present in mid and late working life. Associations between COPD and work functioning were absent in mid working life but present in late working life. Occupational health professionals could use the WRFQ to identify workers' perceived difficulties in meeting specific work demands, pointing out directions for interventions to mitigate perceived difficulties and thereby improve sustainable employability.</p

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

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)

A dimension-breaking phenomenon for water waves with weak surface tension

It is well known that the water-wave problem with weak surface tension has small-amplitude line solitary-wave solutions which to leading order are described by the nonlinear Schr\"odinger equation. The present paper contains an existence theory for three-dimensional periodically modulated solitary-wave solutions which have a solitary-wave profile in the direction of propagation and are periodic in the transverse direction; they emanate from the line solitary waves in a dimension-breaking bifurcation. In addition, it is shown that the line solitary waves are linearly unstable to long-wavelength transverse perturbations. The key to these results is a formulation of the water wave problem as an evolutionary system in which the transverse horizontal variable plays the role of time, a careful study of the purely imaginary spectrum of the operator obtained by linearising the evolutionary system at a line solitary wave, and an application of an infinite-dimensional version of the classical Lyapunov centre theorem.Comment: The final publication is available at Springer via http://dx.doi.org/10.1007/s00205-015-0941-

Defrosting and cooking frozen meat: The effect of method of defrosting and of the manner and temperature of cooking upon weight loss and palatability

The primary objective of this study was to determine the time for defrosting cuts of beef, veal, Iamb and pork by four methods and to consider the effect of the method of defrosting upon the palatability of the cooked meat. The methods of defrosting were: (1) in the refrigerator, (2) at room temperature, (3) in water and (4) during cooking. Data to determine the weight loss during defrosting, weight loss during cooking, time for cooking and the amount of fuel needed for cooking were also recorded. The methods of cooking employed with the different cuts of meat were roasting, broiling, pan-broiling, pan-frying, deep-fat frying, braising and cooking in water. More than one cooking temperature was used for most of the cooking methods

Particle trajectories in linearized irrotational shallow water flows

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

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}

We prove uniqueness of ground state solutions $Q = Q(|x|) \geq 0$ for the nonlinear equation $(-\Delta)^s Q + Q - Q^{\alpha+1}= 0$ in $\mathbb{R}$, where $0 < s < 1$ and $0 < \alpha < \frac{4s}{1-2s}$ for $s < 1/2$ and $0 < \alpha < \infty$ for $s \geq 1/2$. Here $(-\Delta)^s$ 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 $s=1/2$ and $\alpha=1$ in [Acta Math., \textbf{167} (1991), 107--126]. As a technical key result in this paper, we show that the associated linearized operator $L_+ = (-\Delta)^s + 1 - (\alpha+1) Q^\alpha$ is nondegenerate; i.\,e., its kernel satisfies $\mathrm{ker}\, L_+ = \mathrm{span}\, \{Q'\}$. This result about $L_+$ 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