Gun control and suicide: The impact of state firearm regulations, 1995–2004

Suicide is a major cause of preventable death. Restricting access to lethal means has been identified as an effective approach to suicide prevention, and firearms regulations are one way to reduce gun availability. This study examines the relationship between state firearms regulations and suicide among males, using negative binomial regression and state panel data for the years 1995–2004. Results suggest that firearms regulations which function to reduce overall gun availability have a significant deterrent effect on suicide, while prohibited persons categories have less of an effect. Overall, the results suggest that gun control measures such as permit and licensing requirements might have public health benefits.suicide, guns, state regulations, panel data

Epoch profiles: microarchitecture-based application analysis and optimization

The performance of data-intensive applications, when running on modern multi- and many-core processors, is largely determined by their memory access behavior. Its most important contributors are the frequency and latency of off-chip accesses and the extent to which long-latency memory accesses can be overlapped with useful computation or with each other. In this paper we present two methods to better understand application and microarchitectural interactions. An epoch profile is an intuitive way to understand the relationships between three important characteristics: the on-chip cache size, the size of the reorder window of an out-of-order processor, and the frequency of processor stalls caused by long-latency, off-chip requests (epochs). By relating these three quantities one can more easily understand an application’s memory reference behavior and thus significantly reduce the design space. While epoch profiles help to provide insight into the behavior of a single application, developing an understanding of a number of applications in the presence of area and core count constraints presents additional challenges. Epoch-based microarchitectural analysis is presented as a better way to understand the trade-offs for memory-bound applications in the presence of these physical constraints. Through epoch profiling and optimization, one can significantly reduce the multidimensional design space for hardware/software optimization through the use of high-level model-driven techniques

Gun control and suicide: The impact of state firearm regulations, 1995-2004

Suicide is a major cause of preventable death. Restricting access to lethal means has been identified as an effective approach to suicide prevention, and firearms regulations are one way to reduce gun availability. This study examines the relationship between state firearms regulations and suicide among males, using negative binomial regression and state panel data for the years 1995–2004. Results suggest that firearms regulations which function to reduce overall gun availability have a significant deterrent effect on suicide, while prohibited persons categories have less of an effect. Overall, the results suggest that gun control measures such as permit and licensing requirements might have public health benefits.suicide; guns; panel data; state regulations

Apollonian Circle Packings and the Riemann Hypothesis

In this paper, we describe how one can state the Riemann hypothesis in terms of a geometric problem about Apollonian circle packings. We use, as a black box, results of Zagier, and describe numerical experiments which were used in a recent paper by Athreya, Cobeli, and Zaharescu

Semiconductors 1853-1919: an historical study of selenium and some related materials

The history of semiconductors began in 1833 when Faraday noted that the conductivity of silver sulphide increased with temperature. This study ends in 1919 when Pohl went to Göttingen. Five periods are identified: 1833-1895; ^ 1895-1919; 1919-1931; 1931-1948; 1948-present. Only towards the close of the second period was the semiconductor 'class' recognised; until then researches on selenium did not interact with those on other materials. Faraday's discovery excited little interest, but photoconductivity in selenium, 1873, engendered considerable activity during which rectification and photovoltaicity were noted, Allotropic and electrolytic theories were suggested, (by 1877), with the latter being extensively developed. Theories of electricity were insufficiently agreed to form other than a qualitative base for conduction in solids; until the electron theory and Arrhenius's picture, electrolysis was not an unsatisfactory basis on which to construct an account of the properties of selenium. The understanding of electrolysis and the electron theory made an alternative description of the action of selenium desirable and attractive. Initially, to cl912, an allotropic theory was developed to be replaced, by 1914, by an electron theory for there was no direct empirical evidence in support of the former. With the adoption of an electron theory selenium was no longer unique and its properties were compared with those of other non-metallic, non-electrolytic conductors, (cl915). With the electron at the root of all electrical properties a new class of materials was defined, the halbleiter, but at the same time the shortcomings of the 'electron gas' theory were highlighted. By 1919 work on polycrystalline aelenium and naturally occurring materials had extended electrical knowledge; but Pohl's work on single crystals and the development of the quantum theory paved the way for the modern understanding; an understanding whose theoretical beginning was Wilson's theory of 1931

Machine Learning Assisted Non-Rigid Surface Tracking in Biological Systems

Occlusions, obstructions, and lighting changes that occur in a camera's field-of-view (FOV) during a medical procedure can cause tracking algorithms to lose track of a particular region-of-interest (ROI). Various approaches to reacquire the tracking of rigid objects have been developed, however, the non-rigid nature of biological structures requires more complicated approaches. The purpose of this research is to improve the performance of an existing non-rigid tracking algorithm under these types of adverse conditions. This existing algorithm was previously shown to be accurate and efficient under ideal conditions but exhibited a high rate of tracking failures due to the aforementioned occlusions, obstructions, and lighting changes. To improve tracking under these conditions, a tissue motion machine learning model was developed to provide predictions of future ROI grid motion. The combination of this machine learning technique along with various improvements to the base algorithm was shown to greatly reduce the number of tracking resets and allow the tracking grid to briefly follow an expected motion pattern during a simulated occlusion

The Penobscot Boom and the West Branch of the Penobscot River

The Penobscot River, the largest and most important drainage system in Maine, for many years made Bangor the lumber market of the world. Lumbering in Maine was confined to the coast and navigable parts of rivers until the most desirable timber had been removed from these areas. Gradually the lumbermen had to go farther inland to find the large trees. This meant the logs must be driven down the rivers to market. The farther inland the timber was cut, the greater were the obstacles to be overcome. The building of dams, the removal of rocks and other such work must be done to facilitate river driving. The history of the development of the Penobscot River for river driving has never been written. It is the purpose of this paper to make a beginning on such a history. It will be limited to a brief account of the Penobscot Boom above old Town and to the west branch of the Penobscot River. (A version of this thesis was published in 1931 by the University Press with the slightly different title, The Penobscot Boom and the Development of the West Branch of the Penobscot River for Log Driving.