From O\u27Callahan to Chappell: The Burger Court and the Military

In 1969, the United States was deeply committed to a ground war in Southeast Asia in which the suffering and death was brought home daily to the American television viewer. Distrust of the military was never higher, as the repeated assertions of the imminent collapse of the enemy had apparently been graphically belied a year earlier in the Tet Offensive. As a newly elected President pledged to bring peace with honor to a war which seemed amenable to neither, Justice Douglas announced the decision of the Court in O\u27Callahan v. Parker

Correspondence of perceived vs. objective proximity to parks and their relationship to park-based physical activity

<p>Abstract</p> <p>Background</p> <p>Parks are key environmental resources for encouraging population-level physical activity (PA). In measuring availability of parks, studies have employed both self-reported and objective indicators of proximity, with little correspondence observed between these two types of measures. However, little research has examined how the degree of correspondence between self-reported and objectively-measured distance to parks is influenced by individual, neighborhood, and park-related variables, or which type of measure is more strongly related to physical activity outcomes.</p> <p>Methods</p> <p>We used data from 574 respondents who reported the distance to their closest park and compared this with objective measurements of proximity to the closest park. Both indicators were dichotomized as having or not having a park within 750 m. Audits of all park features within this distance were also conducted and other personal characteristics and neighborhood context variables (safety, connectedness, aesthetics) were gleaned from participants' survey responses. Participants also completed detailed seven-day PA log booklets from which measures of neighborhood-based and park-based PA were derived.</p> <p>Results</p> <p>Agreement was poor in that only 18% of respondents achieved a match between perceived and objective proximity to the closest park (kappa = 0.01). Agreement was higher among certain subgroups, especially those who reported engaging in at least some park-based PA. As well, respondents with a greater number of parks nearby, whose closest park had more features, and whose closest park contained a playground or wooded area were more likely to achieve a match. Having a ball diamond or soccer field in the closest park was negatively related to achieving a match between perceived and objective proximity. Finally, engaging in at least some park-based PA was not related to either perceived or objective proximity to a park, but was more likely when a match between and perceived and objective proximity occurred.</p> <p>Conclusion</p> <p>Poor levels of correspondence were observed between self-reported and objective proximity to parks, but certain individual, neighborhood, and park variables increased the likelihood of a participant being aware of local parks. Future research should examine how people conceptualize parks and what urban and park planners can do to increase awareness and use of these community assets.</p

High-energy impact testing of agglomerated cork at extremely low and high temperatures

Agglomerated cork, made from the scraps of wine stoppers, has been finding a wide set of applications due to its excellent thermal and acoustic insulation properties. The random orientation of grains makes the material nearly isotropic, while its dominant viscoelastic behaviour and nearly zero Poisson's ratio make the material also very interesting in applications where dimensional stability is highly demanded. With proven properties, agglomerated cork has been widely used for manufacturing of architectural facades, in civil construction, aerospace engineering and even home appliances production. For outdoor applications, the performance of cork material under different working temperatures is a vital point to be considered. This paper assesses the capability of five different types of cork agglomerates to withstand 500 J impact energy under different temperature conditions. Keeping 11.2 kg impact mass and velocity of 9.2 m/s, impact tests were performed for a wide range of temperatures starting from sub-zero temperature (−30°C) up to 100°C in order to cover a full span of working circumstances. Results show significant variations of amount of absorbed energy depending on testing temperature, calling the attention of designers and product developers for important aspects to be considered upon the application of this material under extreme weather conditions.publishe

Computational Topology Techniques for Characterizing Time-Series Data

Topological data analysis (TDA), while abstract, allows a characterization of time-series data obtained from nonlinear and complex dynamical systems. Though it is surprising that such an abstract measure of structure - counting pieces and holes - could be useful for real-world data, TDA lets us compare different systems, and even do membership testing or change-point detection. However, TDA is computationally expensive and involves a number of free parameters. This complexity can be obviated by coarse-graining, using a construct called the witness complex. The parametric dependence gives rise to the concept of persistent homology: how shape changes with scale. Its results allow us to distinguish time-series data from different systems - e.g., the same note played on different musical instruments.Comment: 12 pages, 6 Figures, 1 Table, The Sixteenth International Symposium on Intelligent Data Analysis (IDA 2017

Streaming Algorithm for Euler Characteristic Curves of Multidimensional Images

We present an efficient algorithm to compute Euler characteristic curves of gray scale images of arbitrary dimension. In various applications the Euler characteristic curve is used as a descriptor of an image. Our algorithm is the first streaming algorithm for Euler characteristic curves. The usage of streaming removes the necessity to store the entire image in RAM. Experiments show that our implementation handles terabyte scale images on commodity hardware. Due to lock-free parallelism, it scales well with the number of processor cores. Our software---CHUNKYEuler---is available as open source on Bitbucket. Additionally, we put the concept of the Euler characteristic curve in the wider context of computational topology. In particular, we explain the connection with persistence diagrams