Effect of plyometric training on swimming block start performance in adolescents

This study aimed to identify the effect of plyometric training (PT), when added to habitual training (HT) regimes, on swim start performance. After the completion of a baseline competitive swim start, 22 adolescent swimmers were randomly assigned to either a PT (n = 11, age: 13.1 ± 1.4 yr, mass: 50.6 ± 12.3 kg, stature: 162.9 ± 11.9 cm) or an HT group (n = 11, age: 12.6 ± 1.9 yr, mass: 43.3 ± 11.6 kg, stature: 157.6 ± 11.9 cm). Over an 8-week preseason period, the HT group continued with their normal training program, whereas the PT group added 2 additional 1-hour plyometric-specific sessions, incorporating prescribed exercises relating to the swimming block start (SBS). After completion of the training intervention, post-training swim start performance was reassessed. For both baseline and post-trials, swim performance was recorded using videography (50Hz Canon MVX460) in the sagital plane of motion. Through the use of Silicon Coach Pro analysis package, data revealed significantly greater change between baseline and post-trials for PT when compared with the HT group for swim performance time to 5.5 m (−0.59 s vs. −0.21 s; p < 0.01) and velocity of take-off to contact (0.19 ms−1 vs. −0.07 ms−1; p < 0.01). Considering the practical importance of a successful swim start to overall performance outcome, the current study has found that inclusion of suitable and safely implemented PT to adolescent performers, in addition to HT routines, can have a positive impact on swim start performance

Combined pyrolysis and radiochemical gas chromatography for studying the thermal degradation of polymers

Pyrolysis gas chromatography and radioactive tracer techniques have been used independently to study the thermal degradation of polymers. In these laboratories the two techniques have been combined to elucidate some of the mechanisms of the thermal degradation of epoxy resins and polyimides. This paper describes the apparatus developed for this work

The Hoyle Family: break-up measurements to probe α-condensation in light nuclei

The 12C Hoyle state is a candidate for α-condensation, due to its large volume and αcluster structure. This paper discusses precision break-up measurements and how they can elucidate α-condensate structures. Two experiments are discussed in detail, firstly concerning the break-up of 12C and then the decays of heavier nuclei. With more theoretical input, and increasingly complex detector setups, precision break-up measurements can, in principle, provide insight into the structures of states in α-conjugate nuclei. At present, such searches have not delivered evidence for α-condensation in 12C or 16O

A Ripple-Turned-Tidal Wave: \u3cem\u3eSEC v. Ripple Labs\u3c/em\u3e as an Inflection Point in the Regulatory Approach to Innovation in Complex Systems

This Comment makes both an observation and an argument about the SEC v. Ripple Labs, Inc. litigation. First, this Comment observes that the facts of the case constitute a challenge to the lack of clarity surrounding the current regulatory regime governing blockchains and initial coin offerings (ICOs). Second, this Comment argues that the Ripple case provides regulators an opportunity to, if they choose, use complexity theory to address technological innovation—such as blockchain—as an emergent phenomenon in a complex system rather than as a binary policy choice to be either encouraged or discouraged. Ripple, the U.S. company behind one of the world’s largest crypto assets by capitalization, deployed a blockchain network designed to remove the traditional friction points of intermediation and settlement from money transfer systems. To obtain widespread adoption of its crypto asset, XRP, both Ripple and its executives sold XRP to speculators and professional investors, but more than five years later—and following a rash of enforcement actions against other blockchain companies—the U.S. Security and Exchange Commission (SEC) brought Ripple and its executives into federal court for allegedly violating U.S. securities laws. The lawsuit is unique because it was not only brought against the company and personnel behind one of the most successful iterations of a novel technology, but effectively, it was brought against a widely held cryptocurrency at a time when pandemic- driven economic and social pressure and billions of dollars in main-street investment in new blockchain technologies was occurring in the wider U.S. economy. But as important as the result of the case is, this Comment suggests that the long view of the case’s impact should be understood through the lens of complexity theory: regulators should, in cases of innovative technology, use this discipline to see the case as both an emergent phenomenon and a point in the trajectory of the larger U.S. economy where innovation and consumer protection are not binary, opposed considerations. To flesh this out, this Comment offers a broad, high-level overview informed by complexity science of the basic operation and recent history of blockchain technology and ICOs as well as the economic forces at work in the U.S. and an explanation of Ripple’s use case. This Comment then will turn to the regulatory history between the SEC and Ripple and analyze the merits of the investment contract approach necessary for SEC jurisdiction. Understanding the history, the parties, and the litigation as parts of a complex system, this Comment concludes by listing several expert suggestions regarding blockchain technologies consistent with obtaining short term stability that the court can take up in dealing with the facts of the case in the light of existing precedent

A CCIR aeronautical mobile satellite report

Propagation effects in the aeronautical mobile-satellite service differ from those in the fixed-satellite service and other mobile-satellite services because: small antennas are used on aircraft, and the aircraft body may affect the performance of the antenna; high aircraft speeds cause large Doppler spreads; aircraft terminals must accommodate a large dynamic range in transmission and reception; and due to their high speeds, banking maneuvers, and three-dimensional operation, aircraft routinely require exceptionally high integrity of communications, making even short-term propagation effects very important. Data and models specifically required to characterize the path impairments are discussed, which include: tropospheric effects, including gaseous attenuation, cloud and rain attenuation, fog attenuation, refraction and scintillation; surface reflection (multipath) effects; ionospheric effects such as scintillation; and environmental effects (aircraft motion, sea state, land surface type). Aeronautical mobile-satellite systems may operate on a worldwide basis, including propagation paths at low elevation angles. Several measurements of multipath parameters over land and sea were conducted. In some cases, laboratory simulations are used to compare measured data and verify model parameters. The received signals is considered in terms of its possible components: a direct wave subject to atmospheric effects, and a reflected wave, which generally contains mostly a diffuse component

Gabor and wavelet analysis with applications to Schatten class integral operators

This thesis addresses four topics in the area of applied harmonic analysis. First, we show that the affine densities of separable wavelet frames affect the frame properties. In particular, we describe a new relationship between the affine densities, frame bounds and weighted admissibility constants of the mother wavelets of pairs of separable wavelet frames. This result is also extended to wavelet frame sequences. Second, we consider affine pseudodifferential operators, generalizations of pseudodifferential operators that model wideband wireless communication channels. We find two classes of Banach spaces, characterized by wavelet and ridgelet transforms, so that inclusion of the kernel and symbol in appropriate spaces ensures the operator is Schatten p-class. Third, we examine the Schatten class properties of pseudodifferential operators. Using Gabor frame techniques, we show that if the kernel of a pseudodifferential operator lies in a particular mixed modulation space, then the operator is Schatten p-class. This result improves existing theorems and is sharp in the sense that larger mixed modulation spaces yield operators that are not Schatten class. The implications of this result for the Kohn-Nirenberg symbol of a pseudodifferential operator are also described. Lastly, Fourier integral operators are analyzed with Gabor frame techniques. We show that, given a certain smoothness in the phase function of a Fourier integral operator, the inclusion of the symbol in appropriate mixed modulation spaces is sufficient to guarantee that the operator is Schatten p-class.Ph.D.Committee Chair: Heil, Christopher; Committee Member: Green, William; Committee Member: Lacey, Michael; Committee Member: Lubinsky, Doron; Committee Member: Moore, Ellio

Research study for determination of liquid surface profile in a cryogenic tank during gas injection Quarterly progress report no. 9, Jun. 18 - Sep. 17, 1966

Determining liquid surface profiles in cryogenic tank during gas injectio

The development of spray-coated perovskite solar cells

Over the past six years, researchers have investigated the use of spray coating to fabricate perovskite solar cells (PSCs), with the aim of demonstrating its viability as an industrial manufacturing process. This spotlight on applications outlines the key benefits of this coating technology and summarizes progress made to date, with attention focused on varied efforts to control the crystallization and uniformity of the perovskite layer. The emerging understanding of processes required to create smooth, dense spray-cast perovskite films has recently led to the demonstration of fully spray-cast PSCs with a power conversion efficiency of 19.4%