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Measuring dynamic hamstring flexibility: Dynamic versus static stretching in the warm-upRebello, Gayle, n/a January 2006 (has links)
The main purpose of this study was to compare the acute effects of static and dynamic stretching
in the warm-up, on hamstring flexibility using a reliable set-up for measurement.
Static and dynamic flexibility was measured using five modifications of the Straight Leg Raise
(SLR) test to measure hip flexion range of motion (ROM). In the first part of the study (n = 33)
hamstring flexibility was measured using a Static-passive, Static-active, Dynamic-supine and
Dynamic-standing tests. The results of this study were used to calculate reliability statistics and
to compare the various static and dynamic flexibility tests. There was a significant difference
between Static-passive (SPH) and the Dynamic-supine (DSUH) tests (p less than .05).
This was followed by an intervention study (n = 12) where participants were randomly assigned
to three intervention treatments of 225 seconds on separate days: No stretching (Treatment I),
Static stretching (Treatment 2) and Dynamic stretching (Treatment 3) in a cross-over study
design. Static stretching had no impact on dynamic hamstring flexibility; however, dynamic
stretching improved dynamic flexibility while simultaneously increasing static flexibility. This
has implications for the specificity of stretching in sport.
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Static Stability of Tension Leg PlatformsXu, Ning 2009 May 1900 (has links)
The static stability of a Tension Leg Platform (TLP) with an intact tendon system is principally provided by its tendons and hence quite different from those of a conventional ship or even a floating structure positioned by its mooring system. Because small deformations in tendons are capable of providing sufficient righting moment to a TLP, the contribution from the inclination of its hull is relatively insignificant, especially when its tendon system is intact. When the tendon system of a TLP is completely damaged, the static stability of a TLP behaves and is calculated in a similar manner as those of a conventional ship. In the case of a TLP with a partially damaged tendon system, the stability of a TLP may be provided by the deformation of its tendons and to a certain extent the inclination of its hull. Several hurricanes in recent years have raised concerns about the feasibility and the robustness of the TLP concept in the deep water Gulf of Mexico. To the best of our knowledge, existing publications on the research of static stability of TLPs are limited. This study investigates the static stability of different types of TLPs representing those deployed in the Gulf of Mexico, under three different scenarios. That is, a TLP with 1) an intact tendon system, 2) a partially damaged tendon system, and 3) a completely damaged tendon system. The four different types of TLP chosen for this study are 1) a conventional four-leg TLP, 2) three-leg mini TLP, 3) extended four-leg TLP and 4) mini four-leg TLP. To avoid buckling and yielding occurring in a tendon, we define that the maximum righting moment provided by an intact or partially damaged tendon system is reached when the tension in one or more tendons on the down tension leg becomes zero or when the tension in one or more tendons on the up tension leg starts to yield. This definition leads us to identify the most dangerous (or vulnerable) directions of met-ocean conditions to a TLP with an intact or partially damaged tendon system. Hence, our finding may also be used in the study on the pitch/roll dynamic stability of a TLP. The righting moments of each TLP in the three different scenarios are respectively computed and compared with related wind-induce static upsetting moment at certain velocities. By comparing their ratios, the static stability of a TLP and the redundancy of its tendon system may be revealed, which has important implication to the design of a TLP.
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Social factors that affect the behaviour and productivity of gestating sows in an electronic sow feeding systemStrawford, Megan Leah 07 March 2006
Previous research has shown that the productivity of sows housed in an Electronic Sow Feeding (ESF) system is affected by the housing management (static vs. dynamic), stage of gestation at mixing and parity. Familiarity has also been shown to affect the behaviour of group-housed sows. Thus, the objective of this experiment was to determine how the previously mentioned social factors affect the behaviour, physiology and productivity of sows housed in an ESF system. Sows were regrouped into either the static and dynamic pens. Within an introduction group, a subgroup of up to 24 focals sows was observed. The focal sows were chosen based on whether they were mixed pre vs. post-implantation (<12 vs. >46 days post-breeding), familiar vs. unfamiliar with group mates and parity (1st vs. 2nd and 3rd vs. 4th +). Aggression at mixing and at the feeder, injury scores, feeder entry order, space usage, salivary cortisol and farrowing productivity was recorded. The data was analyzed using Proc-Mixed and the General Model for SAS. Housing did not have a significant effect on the any of the parameters examined. Young sows had significantly more piglets born alive when housed in a dynamic system, while old sows had more piglets born alive when housed in a static system (p=0.03). Pre-implant sows initiated more aggressive encounters than post-implant sows (p=0.01). Post-implant sows ate later in the feeding cycle (p=0.03), rested on the slats more (p<0.001) and had higher salivary cortisol concentrations (p=0.0008). However, the cortisol concentrations increased throughout gestation for all sows (p<0.001). Familiarity did not have an effect on any of the variables examined except, familiar sows spent more time lying against the wall (p=0.03) and unfamiliar sows spent more time lying in the centre of the solid area of the pen (p=0.02). Old sows were involved in more aggressive encounters (p=0.04), spent more time fighting at mixing (p=0.02) and laid against the wall more (p<0.001). Young sows tended to received more scratches (p=0.07), ate later in the feeding cycle (p<0.001) and spent more time lying on the slats (p<0.001). Intermediate sows had significantly lower salivary cortisol concentrations (p=0.003). There was not a difference between the static and dynamic management systems. Sows should not be mixed until after embryonic implantation because they are more docile. The intermediate sows underwent the least amount of social stress due to their intermediate position within the dominance hierarchy.
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Design Guidelines for Test Level 3 (TL-3) Through Test Level 5 (TL-5) Roadside Barrier Systems Placed on Mechanically Stabilized Earth (MSE) Retaining WallSaez Barrios, Deeyvid 1980- 14 March 2013 (has links)
The use of Mechanically Stabilized Earth (MSE) wall structures has increased dramatically in recent years. Traffic barriers are frequently placed on top of the MSE wall to resist vehicular impact loads. The barrier systems are anchored to the concrete in case of rigid pavement. Nevertheless, in case of flexible pavement, the barriers are constructed in an L shape so that the impact load on the vertical part of the L can be resisted by the inertia force required to uplift the horizontal part of the L. The barrier must be designed to resist the full dynamic load but the size of the horizontal part of the L (moment slab) is determined using an equivalent static load.
Current design practice of barriers mounted on top of MSE retaining wall is well defined for passenger cars and light trucks. However, the information of this impact level is extrapolated to heavy vehicle impact. Therefore, the bases of this research is to develop design procedure and to help understand the dynamic behavior of a barrier-moment slab system on top of an MSE wall when subjected to heavy vehicle impact loads.
In a first part, numerical analyses were conducted to better understand the behavior of the barrier-moment slab system when subjected to heavy vehicle impact loads. The full-scale impact simulations were used to develop the recommendation for designing and sizing the barrier-moment slab system.
In a second part, the barrier-moment slab systems defined to contain heavy vehicle impact loads were placed on top of an MSE wall model to study the kinematic behavior of the system. Loads in the soil reinforcing strips and displacements on the barriers and wall components are evaluated to define recommendation for design of strip reinforcements against pullout and yielding.
In a third part, a full-scale crash test on a barrier-moment slab system on top of an instrumented 9.8 ft. (3 m) high MSE wall is described and analyzed. The MSE wall and barrier system were adequate to contain and redirected the vehicle and, therefore, it served as verification of the proposed recommendation.
Finally, conclusions are drawn on the basis of the information presented herein.
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Static Analysis for Efficient Affine Arithmetic on GPUsChan, Bryan January 2007 (has links)
Range arithmetic is a way of calculating with variables that hold ranges of real values. This ability to manage uncertainty during computation has many applications.
Examples in graphics include rendering and surface modeling,
and there are more general applications like global optimization and
solving systems of nonlinear equations.
This thesis focuses on affine arithmetic, one
kind of range arithmetic.
The main drawbacks of affine arithmetic are
that it taxes processors with heavy
use of floating point arithmetic
and uses expensive sparse vectors to represent
noise symbols.
Stream processors like graphics processing units (GPUs)
excel at intense computation, since they
were originally designed for high throughput
media applications. Heavy control flow and irregular
data structures pose problems though, so the
conventional implementation of affine arithmetic
with dynamically managed sparse vectors runs
slowly at best.
The goal of this thesis is to map affine arithmetic
efficiently onto GPUs by turning sparse vectors
into shorter dense vectors at compile time using
static analysis. In addition,
we look at how to improve efficiency further
during the static analysis using unique symbol
condensation. We demonstrate our implementation and
performance of the condensation on several
graphics applications.
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Static Analysis for Efficient Affine Arithmetic on GPUsChan, Bryan January 2007 (has links)
Range arithmetic is a way of calculating with variables that hold ranges of real values. This ability to manage uncertainty during computation has many applications.
Examples in graphics include rendering and surface modeling,
and there are more general applications like global optimization and
solving systems of nonlinear equations.
This thesis focuses on affine arithmetic, one
kind of range arithmetic.
The main drawbacks of affine arithmetic are
that it taxes processors with heavy
use of floating point arithmetic
and uses expensive sparse vectors to represent
noise symbols.
Stream processors like graphics processing units (GPUs)
excel at intense computation, since they
were originally designed for high throughput
media applications. Heavy control flow and irregular
data structures pose problems though, so the
conventional implementation of affine arithmetic
with dynamically managed sparse vectors runs
slowly at best.
The goal of this thesis is to map affine arithmetic
efficiently onto GPUs by turning sparse vectors
into shorter dense vectors at compile time using
static analysis. In addition,
we look at how to improve efficiency further
during the static analysis using unique symbol
condensation. We demonstrate our implementation and
performance of the condensation on several
graphics applications.
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Social factors that affect the behaviour and productivity of gestating sows in an electronic sow feeding systemStrawford, Megan Leah 07 March 2006 (has links)
Previous research has shown that the productivity of sows housed in an Electronic Sow Feeding (ESF) system is affected by the housing management (static vs. dynamic), stage of gestation at mixing and parity. Familiarity has also been shown to affect the behaviour of group-housed sows. Thus, the objective of this experiment was to determine how the previously mentioned social factors affect the behaviour, physiology and productivity of sows housed in an ESF system. Sows were regrouped into either the static and dynamic pens. Within an introduction group, a subgroup of up to 24 focals sows was observed. The focal sows were chosen based on whether they were mixed pre vs. post-implantation (<12 vs. >46 days post-breeding), familiar vs. unfamiliar with group mates and parity (1st vs. 2nd and 3rd vs. 4th +). Aggression at mixing and at the feeder, injury scores, feeder entry order, space usage, salivary cortisol and farrowing productivity was recorded. The data was analyzed using Proc-Mixed and the General Model for SAS. Housing did not have a significant effect on the any of the parameters examined. Young sows had significantly more piglets born alive when housed in a dynamic system, while old sows had more piglets born alive when housed in a static system (p=0.03). Pre-implant sows initiated more aggressive encounters than post-implant sows (p=0.01). Post-implant sows ate later in the feeding cycle (p=0.03), rested on the slats more (p<0.001) and had higher salivary cortisol concentrations (p=0.0008). However, the cortisol concentrations increased throughout gestation for all sows (p<0.001). Familiarity did not have an effect on any of the variables examined except, familiar sows spent more time lying against the wall (p=0.03) and unfamiliar sows spent more time lying in the centre of the solid area of the pen (p=0.02). Old sows were involved in more aggressive encounters (p=0.04), spent more time fighting at mixing (p=0.02) and laid against the wall more (p<0.001). Young sows tended to received more scratches (p=0.07), ate later in the feeding cycle (p<0.001) and spent more time lying on the slats (p<0.001). Intermediate sows had significantly lower salivary cortisol concentrations (p=0.003). There was not a difference between the static and dynamic management systems. Sows should not be mixed until after embryonic implantation because they are more docile. The intermediate sows underwent the least amount of social stress due to their intermediate position within the dominance hierarchy.
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In Vitro Modulation of Meniscus Biosynthesis: a Basis for Understanding Cellular Response to Physiologically Relevant StimuliImler, Stacy Marie 19 July 2005 (has links)
The meniscus is a soft, fibrocartilaginous tissue critical for the maintenance of normal knee biomechanics, providing shock absorbance and overall joint lubrication and stability. The adult tissue is highly avascular with a poor autonomous repair capacity in response to injury. Despite the estimated 850,000 arthroscopic surgeries performed per year to repair torn menisci and the increasing evidence showing a high incidence of meniscal degeneration during very early stages of osteoarthritis, little is currently known of the responses of meniscal fibrochondrocytes to physiological stimuli. Therefore, this work explored the responses of meniscal fibrochondrocytes to exogenous biomechanical and biochemical stimuli in an effort to better understand the sensitivity of these cells in their native tissue matrix as well as in a 3-D scaffold environment.
Using the immature bovine model, the changes in biosynthesis of fibrochondrocytes in tissue explants and in an agarose scaffold due to unconfined oscillatory compression were explored. This biomechanical stimulus, previously identified to stimulate matrix production of chondrocytes of articular cartilage, stimulated total protein synthesis in both culture environments. In contrast, the synthesis of proteoglycans, matrix components important in mechanical stiffness and hydration of the tissue, was not affected by these compression protocols. However, the use of a biochemical stimulus in the form of anabolic cytokines significantly enhanced both protein and proteoglycan synthesis as a function of culture environment as well as type of cytokine used. The superposition of oscillatory compression in addition to the use of these potent biochemical stimulators, insulin-like growth factor-I or transforming growth factor-beta 1, did not further enhance matrix synthesis of fibrochondrocytes in agarose culture, suggesting an insensitivity of the fibrochondrocytes to biomechanical stimuli during early stages of matrix maturation within the agarose scaffold. As a combination of biomechanical and biochemical stimuli are responsible for directing the development, maintenance, and repair of the tissue, these findings aid in understanding fibrocartilage maintenance through studying responses in a tissue explant model. Additionally, studying agarose scaffolds aid in the understanding fibrocartilage development and deposition of a de novo matrix.
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Statistical static timing analysis considering the impact of power supply noise in VLSI circuitsKim, Hyun Sung 02 June 2009 (has links)
As semiconductor technology is scaled and voltage level is reduced, the impact
of the variation in power supply has become very significant in predicting the realistic
worst-case delays in integrated circuits. The analysis of power supply noise is inevitable
because high correlations exist between supply voltage and delay. Supply noise analysis
has often used a vector-based timing analysis approach. Finding a set of test vectors in
vector-based approaches, however, is very expensive, particularly during the design
phase, and becomes intractable for larger circuits in DSM technology.
In this work, two novel vectorless approaches are described such that increases
in circuit delay, because of power supply noise, can be efficiently, quickly estimated.
Experimental results on ISCAS89 circuits reveal the accuracy and efficiency of my
approaches: in s38417 benchmark circuits, errors on circuit delay distributions are less
than 2%, and both of my approaches are 67 times faster than the traditional vector-based
approach. Also, the results show the importance of considering care-bits, which sensitize
the longest paths during the power supply noise analysis.
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Static Stability of Tension Leg PlatformsXu, Ning 2009 May 1900 (has links)
The static stability of a Tension Leg Platform (TLP) with an intact tendon system is principally provided by its tendons and hence quite different from those of a conventional ship or even a floating structure positioned by its mooring system. Because small deformations in tendons are capable of providing sufficient righting moment to a TLP, the contribution from the inclination of its hull is relatively insignificant, especially when its tendon system is intact. When the tendon system of a TLP is completely damaged, the static stability of a TLP behaves and is calculated in a similar manner as those of a conventional ship. In the case of a TLP with a partially damaged tendon system, the stability of a TLP may be provided by the deformation of its tendons and to a certain extent the inclination of its hull. Several hurricanes in recent years have raised concerns about the feasibility and the robustness of the TLP concept in the deep water Gulf of Mexico. To the best of our knowledge, existing publications on the research of static stability of TLPs are limited. This study investigates the static stability of different types of TLPs representing those deployed in the Gulf of Mexico, under three different scenarios. That is, a TLP with 1) an intact tendon system, 2) a partially damaged tendon system, and 3) a completely damaged tendon system. The four different types of TLP chosen for this study are 1) a conventional four-leg TLP, 2) three-leg mini TLP, 3) extended four-leg TLP and 4) mini four-leg TLP. To avoid buckling and yielding occurring in a tendon, we define that the maximum righting moment provided by an intact or partially damaged tendon system is reached when the tension in one or more tendons on the down tension leg becomes zero or when the tension in one or more tendons on the up tension leg starts to yield. This definition leads us to identify the most dangerous (or vulnerable) directions of met-ocean conditions to a TLP with an intact or partially damaged tendon system. Hence, our finding may also be used in the study on the pitch/roll dynamic stability of a TLP. The righting moments of each TLP in the three different scenarios are respectively computed and compared with related wind-induce static upsetting moment at certain velocities. By comparing their ratios, the static stability of a TLP and the redundancy of its tendon system may be revealed, which has important implication to the design of a TLP.
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