Anticipatory Effects on Lower Extremity Neuromechanics During a Cutting Task

Context: Continued research into the mechanism of noncontact anterior cruciate ligament injury helps to improve clinical interventions and injury-prevention strategies. A better understanding of the effects of anticipation on landing neuromechanics may benefit training interventions. Objective: To determine the effects of anticipation on lower extremity neuromechanics during a single-legged land-and-cut task. Design: Controlled laboratory study. Setting: University biomechanics laboratory. Participants: Eighteen female National Collegiate Athletic Association Division I collegiate soccer players (age = 19.7 ± 0.8 years, height = 167.3 ± 6.0 cm, mass = 66.1 ± 2.1 kg). Intervention(s): Participants performed a single-legged land-and-cut task under anticipated and unanticipated conditions. Main Outcome Measure(s): Three-dimensional initial contact angles, peak joint angles, and peak internal joint moments and peak vertical ground reaction forces and sagittal-plane energy absorption of the 3 lower extremity joints; muscle activation of selected hip- and knee-joint muscles. Results: Unanticipated cuts resulted in less knee flexion at initial contact and greater ankle toe-in displacement. Unanticipated cuts were also characterized by greater internal hip-abductor and external-rotator moments and smaller internal knee-extensor and external-rotator moments. Muscle-activation profiles during unanticipated cuts were associated with greater activation of the gluteus maximus during the precontact and landing phases. Conclusions: Performing a cutting task under unanticipated conditions changed lower extremity neuromechanics compared with anticipated conditions. Most of the observed changes in lower extremity neuromechanics indicated the adoption of a hip-focused strategy during the unanticipated condition

Fumigation of Burrowing Rodents with Carbon Monoxide: A Comparison to Alternative Management Options

Pocket gophers and ground squirrels cause extensive damage to many crops. Pressurized exhaust injection devices are increasingly used for managing these rodents, although no data were available to support their use. Therefore, we established a study to: 1) determine the efficacy of pressurized exhaust machines for pocket gopher and ground squirrel management, 2) compare these results to other burrow fumigant options, and 3) compare their cost effectiveness. Specifically, we tested two different pressurized exhaust machines for both ground squirrels and pocket gophers: Pressurized Exhaust Rodent Controller (PERC), and 2) Cheetah rodent control machine. For California ground squirrels, efficacy for the PERC machine was greater in moist soils (mean = 100%) than in drier soils (mean = 66%). Initial treatments using the PERC machine were more expensive than other burrow fumigation options, given the large cost of the machine. However, costs quickly dropped below that of gas cartridges (~44 days), and eventually dropped below that of aluminum phosphide if used extensively (~830 days). Efficacy for the Cheetah rodent control machine was far less encouraging for California ground squirrels, with results showing increased squirrel numbers at treatment sites (mean = +115%) post-treatment. For pocket gophers, aluminum phosphide (mean = 86%) and trapping (mean = 81%) proved to be more effective than PERC applications (mean = 56%) in heavy organic soils. We observed somewhat greater PERC efficacy in mineral soils (mean = 68%), suggesting potential variability in efficacy across soil types. At this point, the use of the PERC machine appears to be a viable option for inclusion into Integrated Pest Management programs for burrowing rodents where alternative options are limited; the Cheetah rodent control machine showed no utility for ground squirrel management in our study. More extensive testing of pressurized exhaust devices in differing soil types and under variable moisture levels is needed to determine their utility across a broader spectrum of treatment situations

The Association of Dorsiflexion Flexibility on Knee Kinematics and Kinetics during a Drop Vertical Jump in Healthy Female Athletes

Purpose While previous studies have examined the association between ankle dorsiflexion flexibility and deleterious landing postures, it is not currently known how landing kinetics are influenced by ankle dorsiflexion flexibility. The purpose of this study was to examine whether ankle dorsiflexion flexibility was associated with landing kinematics and kinetics that have been shown to increase the risk of anterior cruciate ligament (ACL) injury in female athletes. Methods Twenty-three female collegiate soccer players participated in a preseason screening that included the assessment of ankle dorsiflexion flexibility and lower-body kinematics and kinetics during a drop vertical jump task. Results The results demonstrated that females with less ankle dorsiflexion flexibility exhibited greater peak knee abduction moments (r = −.442), greater peak knee abduction angles (r = .355), and less peak knee flexion angles (r = .385) during landing. The range of dorsiflexion flexibility for the current study was between 9° and 23° (mean = 15.0°; SD 3.9°). Conclusion Dorsiflexion flexibility may serve as a useful clinical measure to predict poor landing postures and external forces that have been associated with increased knee injury risk. Rehabilitation specialists can provide interventions aimed at improving dorsiflexion flexibility in order to ameliorate the impact of this modifiable factor on deleterious landing kinematics and kinetics in female athletes

Hip External Rotator Strength Is Associated With Better Dynamic Control of the Lower Extremity During Landing Tasks

Hip external rotator strength is associated with better dynamic control of the lower extremity during landing tasks. J Strength Cond Res 30(1): 282–291, 2016—The purpose of this study was to determine the association between hip strength and lower extremity kinematics and kinetics during unanticipated single-leg landing and cutting tasks in collegiate female soccer players. Twenty-three National Collegiate Athletic Association division I female soccer players were recruited for strength testing and biomechanical analysis. Maximal isometric hip abduction and external rotation strength were measured using a hand-held dynamometer and expressed as muscle torque (force × femoral length) and normalized to body weight. Three-dimensional lower extremity kinematics and kinetics were assessed with motion analysis and force plates, and an inverse dynamics approach was used to calculate net internal joint moments that were normalized to body weight. Greater hip external rotator strength was significantly associated with greater peak hip external rotation moments (r = 0.47; p = 0.021), greater peak knee internal rotation moments (r = 0.41; p = 0.048), greater hip frontal plane excursion (r = 0.49; p = 0.017), and less knee transverse plane excursion (r = -0.56; p = 0.004) during unanticipated single-leg landing and cutting tasks. In addition, a statistical trend was detected between hip external rotator strength and peak hip frontal plane moments (r = 0.39; p = 0.06). The results suggest that females with greater hip external rotator strength demonstrate better dynamic control of the lower extremity during unanticipated single-leg landing and cutting tasks and provide further support for the link between hip strength and lower extremity landing mechanics

A Biomechanical Comparison of Successful and Unsuccessful Power Clean Attempts

Although the power clean is an almost ubiquitous exercise in the strength and conditioning setting, relatively little is known about the biomechanics of successful and unsuccessful power clean lift attempts. The purpose of this study was to determine biomechanical differences between successful and unsuccessful power clean lift attempts in male collegiate athletes. Fifteen male lacrosse players (Age: 20.1 ± 1.2; Height: 1.78 ± 0.07 m; Body mass: 80.4 ± 8.1 kg; Relative one-repetition maximum power clean: 1.25 ± 0.13 kg/kg) were videotaped during a lifting session that required the completion of maximal effort power cleans to establish a one-repetition maximum. The position of the barbell was digitised and used to calculate the displacement, velocity, acceleration, and acceleration vector of the barbell. The results revealed that unsuccessful attempts were characterised by differences during the second pull phase. Unsuccessful lifts exhibited greater peak forward barbell displacement, lower backward barbell velocities, and lower resultant acceleration angles during the second pull. Strength and conditioning coaches should therefore emphasise limited forward motion of the barbell during the second pull and instruct athletes to generate a more backward-directed force during the second pull in order to lift greater loads during testing and subsequent lifting sessions

Scalable Neural Decoder for Topological Surface Codes

With the advent of noisy intermediate-scale quantum (NISQ) devices, practical quantum computing has seemingly come into reach. However, to go beyond proof-of-principle calculations, the current processing architectures will need to scale up to larger quantum circuits which in turn will require fast and scalable algorithms for quantum error correction. Here we present a neural network based decoder that, for a family of stabilizer codes subject to depolarizing noise, is scalable to tens of thousands of qubits (in contrast to other recent machine learning inspired decoders) and exhibits faster decoding times than the state-of-the-art union find decoder for a wide range of error rates (down to 1%). The key innovation is to autodecode error syndromes on small scales by shifting a preprocessing window over the underlying code, akin to a convolutional neural network in pattern recognition approaches. We show that such a preprocessing step allows to effectively reduce the error rate by up to two orders of magnitude in practical applications and, by detecting correlation effects, shifts the actual error threshold to $p_{\rm threshold} = 0.167(0)$, some ten percent higher than the threshold of conventional error correction algorithms such as union find or minimum weight perfect matching. An in-situ implementation of such machine learning-assisted quantum error correction will be a decisive step to push the entanglement frontier beyond the NISQ horizon.Comment: 9 pages, 8 figures, 5 table

Phantoms to Placentas: MR Methods for Oxygen Quantification

Molecular oxygen (O2) is vital for efficient energy production and improper oxygenation is a hallmark of disease or metabolic dysfunction. In many pathologies, knowledge of tissue oxygen levels (pO2) could aid in diagnosis and treatment planning. The gold standard for pO2 measures in tissue are implantable probes, which are invasive, require surgery for placement, and are inaccessible to certain regions of the body. Methods for determining pO2 both non-invasively and quantitatively are lacking. The slight paramagnetic nature of O2 provides opportunities to non-invasively characterize pO2 in tissue via magnetic resonance (MR) techniques. As such, O2 can be treated as a weak endogenous contrast agent for longitudinal relaxation and, therefore, the measured longitudinal relaxation rate constant (R1) is directly proportional to pO2. Precise characterization of R1 in the absence of oxygen (R1,0) and the relaxivity of O2 (r1) would allow for an R1-based pO2 measurement. Additionally, the effective transverse relaxation rate constant (R2*) in tissue is strongly affected by the magnetic susceptibility effects of deoxyhemoglobin within the vasculature. Many forms of placental dysfunction, e. g. , pre-eclampsia and intrauterine growth restriction, are proposed to be caused by altered vasculature development within the placenta, potentially leading to adverse outcomes for both mother and fetus. Improved biomarkers of placental function would aide in optimal timing for early delivery once the placenta can no longer support fetal development. The objectives of this dissertation were to: 1) investigate the efficacy of an R1-based method of pO2 quantification in a tissue surrogate; and 2) apply MR methods of monitoring pO2 in tissue and O2 within the vasculature in mouse models of disease and insufficiency to assess placental development and function. For the first goal, Bayesian probability theory-based model selection was used to evaluate potential models of longitudinal relaxation in in vivo tissue and an in vitro tissue surrogate, crosslinked bovine serum albumin (xBSA). xBSA was then used to investigate physiologic confounds to an R1-based method of pO2 quantification, including temperature, pH, and protein concentration, and R1,0 and r1 were determined. For the second goal, mouse models of both placental insufficiency and Zika virus infection during pregnancy were monitored in late gestation for changes in volume, R1, and R2* at baseline and with a gas challenge to assess the placental response to an altered environment. It was found that 1) both in vivo and xBSA relaxation data are best fit with a biexponential model and, therefore, xBSA is a good surrogate for tissue, in terms of longitudinal relaxation; 2) physiologic confounds to an R1-based method of pO2 quantification exert considerable affects upon measured R1 and must, therefore, be precisely controlled or accounted for; 3) placental volume, R2*, and change in R2* due to a breathing gas challenge hold promise as biomarkers of placental development and dysfunction. These findings suggest that an R1-based method for pO2 quantification in vivo is likely not feasible on a routine basis due to the small water relaxivity of pO2 and confounds to the analysis due to relaxation effects of tissue pH, temperature, and protein concentration, but MR methods could provide much needed information regarding placental function in high risk pregnancies and warrants further investigation

A proposta do Programa de Extensão: técnicas de bioconstrução aplicadas ao contexto regional

Anais do 35º Seminário de Extensão Universitária da Região Sul - Área temática: Meio Ambiente, Tecnologia e ProduçãoNa formação do profissional arquiteto, os cursos de arquitetura trabalham uma variedade de conteúdos e algumas disciplinas são vistas de maneira rasa. Neste contexto generalista, estão as técnicas vernaculares de construção e a bioconstrução. No contexto atual de industrialização, constante renovação e desperdício de materiais, é necessário que se busque alternativas para minimizar as consequências geradas pelas atividades que competem à construção civil. A bioconstrução entrepõem-se neste contexto trazendo o conceito de sustentabilidade para a produção arquitetônica e proporcionando a aproximação com técnicas construtivas ligadas à cultura brasileira e ao meio ambiente por utilizarem materiais e mão de obra de construção locais. Buscando aproximar-se das técnicas e materiais não convencionais de construção, surge o programa de extensão “Técnicas de bioconstrução aplicadas ao contexto regional” que traz como proposta a abordagem de diversos conceitos ligados a sustentabilidade do ambiente construído e as técnicas de construção vernaculares, vivenciando-as de maneira teórica e prátic

O IMAGINÁRIO DA FORMAÇÃO DO IV REICH NA AMÉRICA LATINA

Após a Segunda Guerra Mundial houve a formação de um imaginário político conspiratório de que o IV Reich poderia se erguer na América Latina, devido ao fato de muitos dos integrantes do alto escalão nazista, como Eichmann, Mengele e Klaus Barbie, terem escapado do tribunal de Nuremberg e se refugiado em terras latino-americanas. Esse imaginário foi representado por livros, filmes, programas de televisão e matérias de jornais e revistas. Exemplo disso é a obra do escritor norte-americano Ladislas Farago que publicou em 1974 o livro intitulado “Aftermath. Martin Bormann and the Fourth Reich”, na qual é narrada a caça a Martin Bormann pela América do Sul, ao mesmo tempo em que denuncia uma conspiração para a formação do IV Reich no continente. Esse artigo visa identificar e analisar esse imaginário presente nos mais variados meios de comunicação. &nbsp