A biomechanical analysis of the heavy sprint-style sled pull and comparison with the back squat

This study compared the biomechanical characteristics of the heavy sprint-style sled pull and squat. Six experienced male strongman athletes performed sled pulls and squats at 70% of their 1RM squat. Significant kinematic and kinetic differences were observed between the sled pull start and squat at the start of the concentric phase and at maximum knee extension. The first stride of the heavy sled pull demonstrated significantly (

Is the Urban Coyote a Misanthropic Synanthrope? The Case from Chicago

Coyotes appear to be one of the few mammalian carnivores that occur in urban areas, although their true relationship with urbanization remains poorly understood. We summarize results from a long-term study of the urban ecology of coyotes in the Chicago metropolitan area to determine the degree of synanthropy for this species and discuss the subsequent management implications for human-coyote conflicts. Local population densities were slightly higher, and survival rates for pups were five times higher compared to rural populations. In contrast to demographic patterns, behavioral responses to urbanization, including home range size, avoidance of developed land cover, activity budget, and diet, were not consistent with synanthropy, even for coyotes located in the urban matrix. We discuss the management implications of the paradoxical relationship coyotes have with people and cities

The mixed problem in Lipschitz domains with general decompositions of the boundary

This paper continues the study of the mixed problem for the Laplacian. We consider a bounded Lipschitz domain $\Omega\subset \reals^n$, $n\geq2$, with boundary that is decomposed as $\partial\Omega=D\cup N$, $D$ and $N$ disjoint. We let $\Lambda$ denote the boundary of $D$ (relative to $\partial\Omega$) and impose conditions on the dimension and shape of $\Lambda$ and the sets $N$ and $D$. Under these geometric criteria, we show that there exists $p_0>1$ depending on the domain $\Omega$ such that for $p$ in the interval $(1,p_0)$, the mixed problem with Neumann data in the space $L^p(N)$ and Dirichlet data in the Sobolev space $W^ {1,p}(D)$ has a unique solution with the non-tangential maximal function of the gradient of the solution in $L^p(\partial\Omega)$. We also obtain results for $p=1$ when the Dirichlet and Neumann data comes from Hardy spaces, and a result when the boundary data comes from weighted Sobolev spaces.Comment: 36 page

Highly Sensitive Dual-Core Photonic Metal Fiber

In this study, we propose an all-solid cladding dual-core metal fiber (DC-MF) filled with toluene and ethanol for temperature sensing applications. Instead of using air holes in the cladding region, we employ fluorine doped silica glass to form an all-solid cladding. By selectively filling toluene and ethanol into three air holes near the core region, we investigate the temperature sensing characteristics numerically. Simulation results demonstrate that the average sensitivity of the temperature sensing can reach -11.64 and -7.41 nm/C within the temperature ranges of 0 to 70 C and -80 to 0 C, respectively, even with a short DC-MF length of 1.6 mm. The maximum sensitivity in the considered temperature ranges can reach up to -15 and -9 nm/C, respectively. Furthermore, the proposed temperature sensor exhibits insensitivity to hydrostatic pressure

Agreement of a Novel Vertical Jump System to Measure Vertical Jump Height: Brower Vertical Jump and Vertec Vertical Jump Systems

Topics in Exercise Science and Kinesiology Volume 2: Issue 1, Article 12, 2021. Validity refers to the ability of a device to measure what it was intended to measure. Therefore, purpose of this study was to assess the validity and reliability of a novel vertical jump height tool designed by Brower Timing Systems (Salt Lake City, Ut). The Brower vertical jump system was compared to the Vertec jump tester. A convenience sample (n=67) of college students performed three maximum countermovement jumps, with the average score being recorded. Data was collected simultaneously for both devices. Results showed a strong and statistically significant correlation between the Vertec vertical jump tester and Brower vertical jump (r = 0.971, p \u3c 0.001.) A paired t-test showed no significant difference (p = 0.170, t = 1.386) between the two systems. An analysis of equivalence was also performed with alpha set at 0.05 and an upper and lower bound set at +/- 0.5. The observed effect was statistically not different from zero and statistically equivalent to zero. Based on the statistical analysis, it can be concluded the Vertec and Brower vertical jump height systems have a high correlation and are equivalent. The Brower system can be an option for assessing vertical jump height, specifically, the Brower system may be useful for high throughput field environments such as testing teams or larger groups to provide valid data

Body Composition of Utah Highway Patrol Officers: No Difference Between Air Displacement Plethysmography and Alternative Tools for Measurement and Prediction.

Topics in Exercise Science and Kinesiology Volume 3: Issue 1, Article 6, 2022. Different techniques exist for examining body composition. The purpose of this study was to examine differences in body fat percentage as measured by air displacement plethysmography (ADP), body adiposity index (BAI), bioelectrical impedance (BIA), a body mass index conversion equation (BMID), and skinfolds (SKF). Twenty-one male Utah Highway Patrol Officers participated in this study (age 35.19 ± 10.32 years, 1.79 ± 0.09 m tall, 92.20 ± 14.56 kg in weight, and 105.52 ± 10.01 cm hip circumference). All measurements were taken during a single visit and performed in the same order for all participants beginning with BIA, followed by ADP, and SKF. The BAI and BMI conversion equation were later calculated. For ADP and SKF the Brozek equation was used to convert body density to percent body fat (%BF). No significant differences were found among the different measurement techniques. No significant correlations were found between ADP, BAI, BIA, BMID, and SKF. Bland-Altman plots revealed small levels of bias, however, the upper and lower limits of agreement were large for all measures. Prediction equations such as BAI and BMID may be cheaper and faster for assessing large populations when compared with traditional laboratory techniques. This study found no significant different among the measurement techniques. Despite the non-significant differences, the authors suggest using a single measurement technique and not using techniques interchangeably

Dissecting a wildlife disease hotspot: the impact of multiple host species, environmental transmission and seasonality in migration, breeding and mortality

Avian influenza viruses (AIVs) have been implicated in all human influenza pandemics in recent history. Despite this, surprisingly little is known about the mechanisms underlying the maintenance and spread of these viruses in their natural bird reservoirs. Surveillance has identified an AIV ‘hotspot’ in shorebirds at Delaware Bay, in which prevalence is estimated to exceed other monitored sites by an order of magnitude. To better understand the factors that create an AIV hotspot, we developed and parametrized a mechanistic transmission model to study the simultaneous epizootiological impacts of multi-species transmission, seasonal breeding, host migration and mixed transmission routes. We scrutinized our model to examine the potential for an AIV hotspot to serve as a ‘gateway’ for the spread of novel viruses into North America. Our findings identify the conditions under which a novel influenza virus, if introduced into the system, could successfully invade and proliferate

Dissecting a wildlife disease hotspot: the impact of multiple host species, environmental transmission and seasonality in migration, breeding and mortality

Avian influenza viruses (AIVs) have been implicated in all human influenza pandemics in recent history. Despite this, surprisingly little is known about the mechanisms underlying the maintenance and spread of these viruses in their natural bird reservoirs. Surveillance has identified an AIV ‘hotspot’ in shorebirds at Delaware Bay, in which prevalence is estimated to exceed other monitored sites by an order of magnitude. To better understand the factors that create an AIV hotspot, we developed and parametrized a mechanistic transmission model to study the simultaneous epizootiological impacts of multi-species transmission, seasonal breeding, host migration and mixed transmission routes. We scrutinized our model to examine the potential for an AIV hotspot to serve as a ‘gateway’ for the spread of novel viruses into North America. Our findings identify the conditions under which a novel influenza virus, if introduced into the system, could successfully invade and proliferate

2169 steel waveform experiments.

In support of LLNL efforts to develop multiscale models of a variety of materials, we have performed a set of eight gas gun impact experiments on 2169 steel (21% Cr, 6% Ni, 9% Mn, balance predominantly Fe). These experiments provided carefully controlled shock, reshock and release velocimetry data, with initial shock stresses ranging from 10 to 50 GPa (particle velocities from 0.25 to 1.05 km/s). Both windowed and free-surface measurements were included in this experiment set to increase the utility of the data set, as were samples ranging in thickness from 1 to 5 mm. Target physical phenomena included the elastic/plastic transition (Hugoniot elastic limit), the Hugoniot, any phase transition phenomena, and the release path (windowed and free-surface). The Hugoniot was found to be nearly linear, with no indications of the Fe-phase transition. Releases were non-hysteretic, and relatively consistent between 3- and 5-mm-thick samples (the 3 mm samples giving slightly lower wavespeeds on release). Reshock tests with explosively welded impactors produced clean results; those with glue bonds showed transient releases prior to the arrival of the reshock, reducing their usefulness for deriving strength information. The free-surface samples, which were steps on a single piece of steel, showed lower wavespeeds for thin (1 mm) samples than for thicker (2 or 4 mm) samples. A configuration used for the last three shots allows release information to be determined from these free surface samples. The sample strength appears to increase with stress from ~1 GPa to ~ 3 GPa over this range, consistent with other recent work but about 40% above the Steinberg model