3,613 research outputs found
Physiological Studies of Heat Stress Acclimation During a Specific Exercise Regimen
Eleven subjects were used to determine if the exercise regimen of racquetball could be used as a heat stress acclimator. Core temperature, skin temperature, sweat production, and weight loss were recorded during a racquetball match. Skin and core temperatures were determined by using thermistors. Sweat was collected with modified stress electrodes. Weight loss was recorded by comparing nude weights at the beginning and end of a match. The results indicated that an hour of strenuous racquetball play caused a significant increase in core temperature with subsequent sweating which resulted in a significant decrease in skin temperature and weight loss. The exercise regimen of racquetball can act as a good heat stress acclimator because it produces sufficiently high levels of hyperthermia
Determination of aerodynamic sensitivity coefficients for wings in transonic flow
The quasianalytical approach is applied to the 3-D full potential equation to compute wing aerodynamic sensitivity coefficients in the transonic regime. Symbolic manipulation is used to reduce the effort associated with obtaining the sensitivity equations, and the large sensitivity system is solved using 'state of the art' routines. The quasianalytical approach is believed to be reasonably accurate and computationally efficient for 3-D problems
Exploring Craft Brewery Owners\u27 Success Though Stakeholder Involvement
In 2014, 547 new breweries opened in the United States and more than 2 million barrels of beer were produced by American homebrewers. Craft brewery owners face challenges in increasing profit because of intense competition from existing breweries, new ventures, and homebrewers. The purpose of the study was to explore the strategies that craft brewery owners used to increase profits by collaboratively working with internal and external stakeholders, such as employees, distributors, customers, suppliers, lending groups, and community organizations. The conceptual framework of this multiple-case study was the stakeholder theory. The basic tenet of the stakeholder theory is that a business owner can maximize the firm\u27s financial performance if the business owner proactively meets the needs of the relevant stakeholders. Face-to-face interviews were conducted on a purposeful sample of 5 craft brewery owners who met the study criteria of operating a profitable brewery in southern Maine for a minimum of 5 years. Transcripts, direct observations, and industry documents were organized to create common themes for coding in accordance with Yin\u27s method of data analysis. Through methodological triangulation, the following 4 themes emerged: employee satisfaction and retention, nontraditional marketing, commitment to quality, and development of local relationships. Within these themes, craft brewery owners can apply a number of strategies to increase profits through stakeholder collaboration. The implications for social change include partnering of breweries with local establishments, which can foster increased sales for both businesses and provide better jobs for the local community
An Evaluation of the Physical Education Instructional Programs of Selected Community Colleges in the State of Washington
The specific problem dealt with in this study was the evaluation of existing physical education instructional programs at five community colleges in the State of Washington. The purposes of this study were to: (1) determine the present status of philosophy and objectives of physical education, (2) determine the role of administration in developing general principles and policies as they relate to the instructional program, (3) determine the instructional programs of physical education at the selected community colleges, and (4) determine the evaluation methods used at each of the community colleges as these methods relate to the instructional program of physical education
Satellite-Derived Bathymetry Using Multiple Images: The Alaska North Slope Case Study
Currently, charting data in much of the U.S. Arctic North Slope is inadequate or nonexistent and most of its areas have not been updated since the early-1950s. Although the charting infrastructure is out of date, ship transportation (such as, fishing and transit between the towns) has increased. NOAA conducted a preliminary multibeam survey in 2013 that reached Point Barrow, AK. However, all the Arctic North Slope remained untouched. Previous studies have shown that satellite-derived bathymetry (SDB) is a useful reconnaissance tool in tropical and sub-tropical waters in clear water conditions, especially over sandy seafloor. However, it is very difficult to extract good information over the Arctic using a single satellite image, especially over the U.S. North Slope. The glacial powder from land reduces the water clarity that limits the light penetration depth. Also, this turbidity is not uniform along the coast line and may affect the calculations. In this paper, a new SDB approach was developed that compiles multiple satellite images to extract only areas that were identified clear by comparison (i.e., minimum water clarity change between two satellite images). Preliminary results using Landsat 7 imagery from 1999-2002 and Landsat 8 imagery from 2013 are presented
Degenerate Variational Integrators for Magnetic Field Line Flow and Guiding Center Trajectories
Symplectic integrators offer many advantages for the numerical solution of
Hamiltonian differential equations, including bounded energy error and the
preservation of invariant sets. Two of the central Hamiltonian systems
encountered in plasma physics --- the flow of magnetic field lines and the
guiding center motion of magnetized charged particles --- resist symplectic
integration by conventional means because the dynamics are most naturally
formulated in non-canonical coordinates, i.e., coordinates lacking the familiar
partitioning. Recent efforts made progress toward non-canonical
symplectic integration of these systems by appealing to the variational
integration framework; however, those integrators were multistep methods and
later found to be numerically unstable due to parasitic mode instabilities.
This work eliminates the multistep character and, therefore, the parasitic mode
instabilities via an adaptation of the variational integration formalism that
we deem ``degenerate variational integration''. Both the magnetic field line
and guiding center Lagrangians are degenerate in the sense that their resultant
Euler-Lagrange equations are systems of first-order ODEs. We show that
retaining the same degree of degeneracy when constructing a discrete Lagrangian
yields one-step variational integrators preserving a non-canonical symplectic
structure on the original Hamiltonian phase space. The advantages of the new
algorithms are demonstrated via numerical examples, demonstrating superior
stability compared to existing variational integrators for these systems and
superior qualitative behavior compared to non-conservative algorithms
Indirect interaction between two native thistles mediated by an invasive exotic floral herbivore
Spatial and temporal variation in insect floral herbivory is common and often important. Yet, the determinants of such variation remain incompletely understood. Using 12 years of flowering data and 4 years of biweekly insect counts, we evaluated four hypotheses to explain variation in damage by the Eurasian flower head weevil, Rhinocyllus conicus, to the native North American wavyleaf thistle, Cirsium undulatum. The four factors hypothesized to influence weevil impact were variations in climate, weevil abundance, phenological synchrony, and number of flower heads available, either on wavyleaf thistle or on the other co-occurring, acquired native host plant (Platte thistle, Cirsium canescens), or on both. Climate did not contribute significantly to an explanation of variation in R. conicus damage to wavyleaf thistle. However, climate did influence weevil synchrony with wavyleaf flower head initiation, and phenological synchrony was important in determining R. conicus oviposition levels on wavyleaf thistle. The earlier R. conicus was active, the less it oviposited on wavyleaf thistle, even when weevils were abundant. Neither weevil abundance nor availability of wavyleaf flower heads predicted R. conicus egg load. Instead, the strongest predictor of R. conicus egg load on wavyleaf thistle was the availability of flower heads on Platte thistle, the more common, earlier flowering native thistle in the sand prairie. Egg load on wavyleaf thistle decreased as the number of Platte thistle flower heads at a site increased. Thus, wavyleaf thistle experienced associational defense in the presence of flowering by its now declining native congener, Platte thistle. These results demonstrate that prediction of damage to a native plant by an exotic insect may require knowledge of both likely phenological synchrony and total resource availability to the herbivore, including resources provided by other nontarget native species
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