Tank Tests of a Model of the NC Flying-boat Hull - N.A.C.A. Model 44

A 1/7.06 full-size model of the NC-type hull was tested in the N.A.C.A. tank by both the general method and the specific or free-to-trim method. The results of the tests are given in curves plotted as non dimensional coefficients and are compared with the test results of N.A.C.A. model 11-A. The NC model (N.A.C.A. model 44) shows higher resistance than model 11-A at hump speed but lower resistance at high speeds. Model 44 has a higher best trim angle at the jump and a lower maximum positive trimming moment than model 11-A. At high speeds the best trim angle and the trimming moments of the two models are approximately the same

Tank Tests of Two Floats for High-speed Seaplanes

At the request of the Bureau of Aeronautics, Navy Department, a study of the design of floats especially suitable for use on high-speed seaplanes was undertaken in the N.A.C.A. tank. This note give the results obtained in tests of one-quarter full-size models of two floats for high-speed seaplanes. One was a float similar to that used on the Macchi high-speed seaplane which competed in the 1926 Schneider Trophy races, and the other a float designed at the N.A.C.A. tank in an attempt to improve on the water performance of the Macchi float. The model of the latter showed considerably better water performance than the model of the Macchi float

The effect of depth of step on the water performance of a flying-boat hull model

NACA model 11-C was tested with four different depths of step to obtain information as to the effect of the depth of step on the water performance. The depths of step were selected to cover the practicable range of depths and in each case the included angle between the forebody and afterbody keels was kept the same 6-1/2 degrees. Small depths of step were found to give lower resistance at speeds below and at the hump speed of the model and greater depths of step lower resistance at high speeds. For low resistance throughout the speed range of the model investigated the most desirable depth of step is from 2.5 to 4.0 percent of the beam. The change of the best trim angle caused by variation of the depth of step was not appreciable. Increased depth of step caused increases in the maximum positive trimming moments at all trim angles investigated

Demonstrable Evidence of Beneficial Physical Outcomes from University Physical Education Activity Courses

Introduction: Engagement in physical activity (PA) is often dramatically reduced during the transition from high school into college. There appears to be more stability in PA patterns during the transition from college into post-graduate life. Consequently, researchers have highlighted the years in higher education as pivotal for shaping lasting PA habits. Sadly, there is a widespread lack of evidence regarding the outcomes from physical education activity courses (PEAC) offered on campuses of higher education. Thus, their overall value lacks validation. The purpose of this work was to offer evidence of outcomes from engagement in a single, semester-long university PEAC class. Methods: Students were recruited from a variety of classes. There were no directions provided to the instructors of the courses. For grouping, classes were categorized as aerobic- (aerobics, jogging, and walking) or sport-activity (badminton, pickle ball, self-defense, strength training, and ultimate frisbee). Students in the aerobic-activity arm were randomized to aerobic testing where they underwent a submaximal treadmill protocol and grip strength (GS) testing or body composition testing (air displacement plethysmography) and GS. Those in the sport-activity arm underwent vertical jump and GS testing. Students reported to the human performance lab in the first two and final two weeks of the semester. Paired t-tests were conducted to identify differences in pre-post outcomes. Values were carried forward, not dropped, when a subject failed to return at post-test. Results: A total of 46 students (age = 21.7 ± 4.1) were randomized into the aerobic (n=25; m/f = 11/14) or body composition arms (n=21; m/f = 7/14). Additionally, 45 students (age = 20.8 ± 3.2; m/f = 23/22) from sport-activity classes were enrolled. Participation in aerobic-activity classes resulted in improvements in estimated maximal aerobic ability (p = 0.030; 42.9 ± 9.9 vs. 44.6 ± 10.1). Participation also resulted in increases in GS for those allocated to both the aerobic (p = 0.010; 56.4 ± 21.5 vs. 60.3 ± 22.3) and body composition (p = 0.022; 54.1 ± 22.1 vs. 58.1 ± 24.6) arms. Participation did not result in changes in body composition (p = 0.817; 24.7 ± 8.5 vs. 24.6 ± 7.4) despite a near-significant increase in weight (p = 0.057; 152.7 ± 38.5 vs. 154.5 ± 37.7). Participation in sport-activity classes resulted in an improvement in vertical jump (p = 0.007; 18.2 ± 6.1 vs. 18.9 ± 6.0) and GS (p = 0.002; 65.3 ± 25.6 vs. 70.0 ± 27.8). Discussion: An important first step in rebutting challenges about the credibility and worthiness of PEAC offerings is evidencing beneficial outcomes. These results represent simple, but important, markers of change. Additional demonstrable evidence is needed to ascertain elements such as what outcomes are achievable, what classes are most effective classes, and what components from class support lasting change

Survey Responses From “Wellness for Life” Classes: Overall Value and Barriers, Motivators, and Motives Towards Physical Activity

Introduction: Skill-based sport activity classes were the historical trend, but greater numbers of higher education institutions now offer courses that encompass “wellness for life” concepts. The goal of these offerings is to guide students in the development of knowledge, skills, and behaviors to adopt and maintain healthful behaviors. There is a need to amass evidence of the outcomes arising from engagement in these classes. Purpose: The purpose of this work was to document outcomes from participation in a single, semester-long, university wellness for life class. Methods: Students were recruited from courses at two universities. Survey responses were collected in the first two and final two weeks of class. The survey items included identification of: engagement in regular physical activity (PA), perceptions about PA (“view of self as an exerciser”, “contentment with current PA level”, among others), and barriers, motivators, and motives towards PA. There were no intervention suggestions provided to instructors. Results: A total of 173 students (m/f/not identified = 51/118/4; age 19.6 ± 1.4) participated. When questioned, many students identified as being an “exerciser.” Some perceived “no need to change their program” (n=37) but most “wanted more regular exercise” (n=88). A lesser number of students identified as being a “non-exerciser.” Most all “wanted more regular exercise” (n=46), but two had “no desire to start a program.” At post-test, the respective numbers were: 37, 95, 41, and 3. Numbers did not always align due to incomplete survey responses. The perceived value of the class to current and future health, rated on a scale from 0 (no impact)-100 (most influential), improved pre-post class (p \u3c 0.001) from 61.7 (±24.5) to 67.8 (±23.5). The top barrier, motivator, and motive at pre-test were: “I need to do better at managing my time to exercise more often,” “If I better organized my time or schedule I could exercise more,” and “I get pleasure or enjoy sports so I exercise,” respectively. There was shuffling among the top choices from pre- to post-test, but the top barrier remained the same. The top motivator became, “If I had more time I would exercise more,” and the top motive became, “I feel less stress after I exercise.” Discussion: Evidenced by the pre-post responses, students feel that wellness for life classes have some benefit and that perception improves after experiencing the class. There appears to be consistency in those who view themselves as “exercisers” and “non-exercisers,” which might represent a precarious situation. There is constancy in the primary barrier to exercise – the socially acceptable answer – time. It is obvious that time management is a critical element for inclusion in these classes. Students may also benefit more if instructors would offer insight on the use of motivators and motives in overcoming personal barriers

A Bell Inequality Analog in Quantum Measure Theory

One obtains Bell's inequalities if one posits a hypothetical joint probability distribution, or {\it measure}, whose marginals yield the probabilities produced by the spin measurements in question. The existence of a joint measure is in turn equivalent to a certain causality condition known as ``screening off''. We show that if one assumes, more generally, a joint {\it quantal measure}, or ``decoherence functional'', one obtains instead an analogous inequality weaker by a factor of $\sqrt{2}$. The proof of this ``Tsirel'son inequality'' is geometrical and rests on the possibility of associating a Hilbert space to any strongly positive quantal measure. These results lead both to a {\it question}: ``Does a joint measure follow from some quantal analog of `screening off'?'', and to the {\it observation} that non-contextual hidden variables are viable in histories-based quantum mechanics, even if they are excluded classically.Comment: 38 pages, TeX. Several changes and added comments to bring out the meaning more clearly. Minor rewording and extra acknowledgements, now closer to published versio

ACR guidance document on MR safe practices: 2013

Because there are many potential risks in the MR environment and reports of adverse incidents involving patients, equipment and personnel, the need for a guidance document on MR safe practices emerged. Initially published in 2002, the ACR MR Safe Practices Guidelines established de facto industry standards for safe and responsible practices in clinical and research MR environments. As the MR industry changes the document is reviewed, modified and updated. The most recent version will reflect these changes. J. Magn. Reson. Imaging 2013;37:501–530. © 2013 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96674/1/24011_ftp.pd

Quantum Histories and Quantum Gravity

This paper reviews the histories approach to quantum mechanics. This discussion is then applied to theories of quantum gravity. It is argued that some of the quantum histories must approximate (in a suitable sense) to classical histories, if the correct classical regime is to be recovered. This observation has significance for the formulation of new theories (such as quantum gravity theories) as it puts a constraint on the kinematics, if the quantum/classical correspondence principle is to be preserved. Consequences for quantum gravity, particularly for Lorentz symmetry and the idea of "emergent geometry", are discussed.Comment: 35 pages (29 pages main body), two figure