481 research outputs found
EFFECTS OF THE BENCH SHIRT ON SELECTED BENCH PRESS MECHANICS
Power lifting is an individual sport enjoyed by participants in over 78 countries. Participants compete in three separate lifts and the Iifter with the highest total is the winner. However. this study is concerned purely with the bench press. The "bench shirt" is a cotton/polyester. single-ply form-fitting shirt that is used by lifters to enhance performance during the bench press. Power lifters use these shirts in an attempt to Increase the load lifted in competition. However, it Is possible that these shirts, due to their extreme form fit to the body, could alter the natural motion of the bench press exercise. Researchers have investigated the mechanics of the bench press. and identified proper technique (Judge, 1998; Madsen & McLaughlin, 1984). Proper mechanics dictate that for any experienced lifter there exists a consistent order of bar velocity (increasing velocity off of the chest, decreasing velocity throug the "sticking region," increasing velocity after the sticking region. final decreasing velocity at the finish) (Madsen & McLaughlin, 1984). The bar path should be as indicated in Figure 1. However, no published studies have demonstrated the effect the bench shirt on bench press lifting technique. Therefore. the purpose of this study was to determine the changes in bar path and bar velocity when performing the bench press shirted versus raw (no bench shirt)
The Black Lives Matter Movement: A Systemic Crisis that Expands Crisis Response Theory
Relevance to Marketing Educators, Researchers, and/or Practitioners â In response to George Floydâs death, a variety of organizations posted messages against racism and some began to openly support Black Lives Matter, often by name, in their corporate communication initiatives. With promises of financial commitments to uplift Black communities, calls for action, and initiatives to support internal changeâlarge and small companies, non-profits and universitiesâcould be perceived as courageous for establishing new protocols to support such a warranted change. However, in the era of âwoke washing,â or inauthentic social justice messaging, the need to assess the authenticity of corporate statements of support to social justice causes has become increasingly imperative to support both social justice causes and corporate outcomes
Surface Fuel Loadings in Mulching Treatments in Colorado Coniferous Forests
Recent large-scale, severe wildfires in the western United States have prompted extensive fuel treatment programs to reduce potential wildfire size and severity. Often, unmerchantable material is mechanically masticated because removing the material is cost-prohibitive. Mastication treatments involve shredding, chopping, or chipping small trees and/or shrubs into small chunks and leaving the material on site. While it is obvious that mechanical treatments will increase surface fuel loads, few studies have addressed how treatments alter fuel particle size and quantity. We examined how mastication treatments alter the distribution of woody material size by comparing paired masticated and untreated sites in lodgepole pine (Pinus contorta), ponderosa pine/Douglas-fir (Pinus ponderosa/Pseudotsuga menziesii), and 3) Pinyon pine (Pinus edulis) ecosystems 2-4 years after mechanical treatment. As expected, total woody fuel loadings increased in the treated areas of each ecosystem. However, the magnitude of the total increase differed among the ecosystems (lodgepole pine \u3e ponderosa pine \u3e pinyon-juniper). Average total woody fuel loads in the untreated areas ranged between 7 to 9 Mg/ha, but increased to 29 to 50 Mg/ha in treated areas. Large diameter fuels (\u3e7.62 cm) represent about 33 to 65% of the total woody fuel load in the untreated areas, but only about 11% of the total fuel load in the treated areas. The majority of woody fuels in treated areas were \u3c2.54 cm in diameter. Needle litter mass was similar among treatments, indicating that needles are still a component of the forest floor complex, but are mixed with other fuel types or buried. The increased surface woody fuel component in treated areas corresponds to a shift from a needle fuel bed to a compact woody/needle fuel bed. This change in the fuel bed composition and orientation will likely influence fire behavior and effects
Implementation of a Supervisor-Led Resilience Training Extension in the Royal Military College
Resilience training offered to military personnel often fails to reinforce training practices into routine military activities. We describe the implementation of a supervisor-led after action review designed to provide personnel with frequent opportunities for the supervisor reinforced application of resilience training skills at work. This paper provides a roadmap for engaging supervisors to support this program and details strategies used across its design and their contribution to implementation fidelity. Strategies included iterative stakeholder engagement in co-design and the use of mixed-methods data collection, including field observational ratings, open ended survey questions, and focus group interviews. The design and implementation process are reported in two phases: initial and re-implementation phases. Chi-square analyses and t-tests of initial phase data indicated that the after action review designed to guide the application of resilience training skills was distinct from preexisting after action reviews of tactical skills and drills. Reflexive interpretations of instructor feedback guided refinement to the extension and subsequent re-implementation phase data indicated implementation fidelity. When engaging leaders and resilience non-specialists in activities that support military resilience training, we recommend involving stakeholders in the design and implementation process, responding flexibly to their concerns, and balancing their experienced work change demands with appropriate resources
Sum of squares lower bounds for refuting any CSP
Let be a nontrivial -ary predicate. Consider a
random instance of the constraint satisfaction problem on
variables with constraints, each being applied to randomly
chosen literals. Provided the constraint density satisfies , such
an instance is unsatisfiable with high probability. The \emph{refutation}
problem is to efficiently find a proof of unsatisfiability.
We show that whenever the predicate supports a -\emph{wise uniform}
probability distribution on its satisfying assignments, the sum of squares
(SOS) algorithm of degree
(which runs in time ) \emph{cannot} refute a random instance of
. In particular, the polynomial-time SOS algorithm requires
constraints to refute random instances of
CSP when supports a -wise uniform distribution on its satisfying
assignments. Together with recent work of Lee et al. [LRS15], our result also
implies that \emph{any} polynomial-size semidefinite programming relaxation for
refutation requires at least constraints.
Our results (which also extend with no change to CSPs over larger alphabets)
subsume all previously known lower bounds for semialgebraic refutation of
random CSPs. For every constraint predicate~, they give a three-way hardness
tradeoff between the density of constraints, the SOS degree (hence running
time), and the strength of the refutation. By recent algorithmic results of
Allen et al. [AOW15] and Raghavendra et al. [RRS16], this full three-way
tradeoff is \emph{tight}, up to lower-order factors.Comment: 39 pages, 1 figur
- âŠ