1,018 research outputs found
Deconstructing the power resistance relationship for squats: a joint-level analysis
Generating high leg power outputs is important for executing rapid movements. Squats are commonly used to increase leg strength and power. Therefore, it is useful to understand factors affecting power output in squatting. We aimed to deconstruct the mechanisms behind why power is maximized at certain resistances in squatting. Ten male rowers (age = 20 ± 2.2 years; height = 1.82 ± 0.03 m; mass = 86 ± 11 kg) performed maximal power squats with resistances ranging from body weight to 80% of their one repetition maximum (1RM). Three-dimensional kinematics was combined with ground reaction force (GRF) data in an inverse dynamics analysis to calculate leg joint moments and powers. System center of mass (COM) velocity and power were computed from GRF data. COM power was maximized across a range of resistances from 40% to 60% 1RM. This range was identified because a trade-off in hip and knee joint powers existed across this range, with maximal knee joint power occurring at 40% 1RM and maximal hip joint power at 60% 1RM. A non-linear system force-velocity relationship was observed that dictated large reductions in COM power below 20% 1RM and above 60% 1RM. These reductions were due to constraints on the control of the movement
Prediction of Fretting Crack Location and Orientation in a Single Crystal Nickel Alloy
Fretting is a structural damage mechanism arising between two nominally clamped surfaces subjected to an oscillatory loading. A critical location for fretting induced damage has been identified at the blade/disk and blade/damper interfaces of gas turbine engine turbomachinery and space propulsion components. The high- temperature, high-frequency loading environment seen by these components lead to severe stress gradients at the edge-of-contact that could potentially foster crack growth leading to component failure. These contact stresses drive crack nucleation in fretting and are very sensitive to the geometry of the contacting bodies, the contact loads, materials, temperature, and contact surface tribology (friction). Recently, a high-frequency, high-temperature load frame has been designed for experimentally investigating fretting damage of single crystal nickel materials employed in aircraft and spacecraft turbomachinery. A modeling method for characterizing the fretting stresses of the spherical fretting contact stress behavior in this experiment is developed and described. The calculated fretting stresses for a series of experiments are then correlated to the observed fretting damage. Results show that knowledge of the normal stresses and resolved shear stresses on each crystal plane can aid in predicting crack locations and orientations
Plasminogen activator‐1 overexpression decreases experimental postthrombotic vein wall fibrosis by a non‐vitronectin‐dependent mechanism
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108289/1/jth12644.pd
Analysis of the superdefomed rotational bands
All available experimental data for the transition energies in
superdeformed bands are analyzed by using a new one-point formula. The
existence of deviations from the smooth behavior is confirmed in many bands.
However, we stress that one cannot necessarily speak about staggering patterns
as they are mostly irregular. Simulations of the experimental data suggest that
the irregularities may stem from the presence of irregular kinks in the
rotational spectra. This could be a clue but, at the moment, where such kinks
come from is an open question.Comment: 6 pages, RevTex, 7 p.s. figures, submitted to P.R.
“'Subaltern Victims’ or ‘Useful Resources”? Migrant Women in the Lega Nord Ideology and Politics"
Since the mid-2000s we have witnessed the emergence of a new phenomenon in several European countries: the mobilisation of issues of women’s rights and gender equality by populist radical right parties (PRR)1 in anti-immigration campaigns. Recent contributions have illustrated some aspects and contradictions of these phenomena, for instance in relation to the PRR parties’ embrace not only of women’s but also gay rights (Bracke 2011). Others have described the double standard applied to migrant men and women in the context of raising hostility towards the Muslim population, not only by PRR parties, but within the mainstream more generally; whereas Muslim men have been mostly described as representing a social and cultural danger to European societies as well as being inherently misogynist, Muslim women have been portrayed prevalently as victims to be rescued (Abu-Lughod 2013). Little however has been written on the gendered ideology and strategies of these parties, particularly when it comes to addressing the issue of migrant women. This chapter aims to address these gaps in the scholarly literature by focusing on the gendered dimensions of anti-immigration ideology, policy and politics in the case of the LN. In particular, we draw on the empirical findings of two research projects to analyse the instrumental mobilisation of women’s rights by the LN to stigmatise migrant, particularly Muslim, communities
High-Frequency, High-Temperature Fretting Experiments
Fretting is a structural damage mechanism observed when two nominally clamped surfaces are subjected to an oscillatory loading. A critical location for fretting induced damage has been identified at the blade/disk and blade/damper interfaces of gas turbine engine turbomachinery and space propulsion components. The high-temperature, high-frequency loading environment seen by these components lead to severe stress gradients at the edge-of-contact. These contact stresses drive crack nucleation and propagation in fretting and are very sensitive to the geometry of the contacting bodies, the contact loads, materials, temperature, and contact surface tribology (friction). To diagnose the threat that small and relatively undetectable fretting cracks pose to damage tolerance and structural integrity of in-service components, the objective of this work is to develop a well-characterized experimental fretting rig capable of investigating fretting behavior of advanced aerospace alloys subjected to load and temperature conditions representative of such turbomachinery components
Global distribution of two fungal pathogens threatening endangered sea turtles
This work was supported by grants of Ministerio de Ciencia e Innovación, Spain (CGL2009-10032, CGL2012-32934). J.M.S.R was supported by PhD fellowship of the CSIC (JAEPre 0901804). The Natural Environment Research Council and the Biotechnology and Biological Sciences Research Council supported P.V.W. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Thanks Machalilla National Park in Ecuador, Pacuare Nature Reserve in Costa Rica, Foundations Natura 2000 in Cape Verde and Equilibrio Azul in Ecuador, Dr. Jesus Muñoz, Dr. Ian Bell, Dr. Juan Patiño for help and technical support during samplingPeer reviewedPublisher PD
Sophisticated falsification and research cycles: Consequences for differential character weighting in phylogenetic systematics
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72703/1/j.1463-6409.1997.tb00424.x.pd
PARSIMONY JACKKNIFING OUTPERFORMS NEIGHBOR-JOINING
Because they are designed to produced just one tree, neighbor-joining programs can obscure ambiguities in data. Ambiguities can be uncovered by resampling, but existing neighbor-joining programs may give misleading bootstrap frequencies because they do not suppress zero-length branches and/or are sensitive to the order of terminals in the data. A new procedure, parsimony jackknifing, overcomes these problems while running hundreds of times faster than existing programs for neighbor-joining bootstrapping. For analysis of large matrices, parsimony jackknifing is hundreds of thousands of times faster than extensive branch-swapping, yet is better able to screen out poorly-supported groups.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73544/1/j.1096-0031.1996.tb00196.x.pd
A Thousand Contradictory Ways: Addiction, Neuroscience, and Expert Autobiography
Neuroscientific accounts of addiction are increasingly influential in health and medical circles. At the same time a diverse, if equally scientifically focused, opposition to addiction neuroscience is emerging. In this struggle over the merits of addiction neuroscience are elements of a uniquely 21st-century public engagement with science. No longer trusted by the public as the unerring source of objective knowledge about the world, science is, at least in some contexts, increasingly treated as just one voice among many. Observing the difficulties this loss of faith in science poses for effective action on pressing issues such as climate change, philosopher Bruno Latour develops a different (ecological) approach to scientific knowledge, one that for the first time allows scientists (and other “moderns”) to understand it for what it really is and locate it “diplomatically” alongside other modes of knowing. In this article, I ask whether a similar innovation is needed to allow more effective understanding of addiction. I explore this question by analyzing two recent, widely discussed, popular books (Marc Lewis’s Memoirs of an Addicted Brain: A Neuroscientist Examines His Former Life on Drugs, 2011 and Carl Hart’s High Price: A Neuroscientist’s Journey of Self-discovery that Challenges Everything You Think You Know About Drugs and Society, 2013) as well as reviews of these books. Written by neuroscientists, and drawing heavily on personal memoir to illustrate and ratify their competing views on drugs and addiction, both books crystallize contemporary dilemmas about science, empiricism, and the nature of evidence and truth. How are we to understand their mix of “scientific fact” and individual self-observation, what does this mix suggest about scientific knowledge, and what are its implications for dominant notions of “evidence-based” drug policy and treatment? I argue that these books both trouble and reinforce our taken-for-granted distinctions between science and personal stories, between objectivity and subjectivity, and note the lost opportunities the books represent for a more searching and productive (Latour might say “ecological”) engagement with science
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