The muon component of extensive air showers

This thesis describes the determination of various characteristics of the muon component of extensive air showers (EAS) using the magnet spectrograph situated at the British Universities joint air shower array at Haverah Park, near Harrogate. After an introduction concerning the relevance of muon studies to current problems in the studies of air showers (Chapter l), the air shower arrays and the magnet spectrograph are briefly described and a summary given of the analysis of the data from each (Chapters 2 and 5)-The lateral density distribution of muons of momentum above 1 GeV/c is determined (Chapter k) for use in the normalization of the measured momentum spectrum of muons. The dependence of the number of muons on shower size is found to be constant over a wide range of size. The momentum spectrum of muons in air showers is determined as a function of distance from the shower core. The variation of spectrum with shower size and zenith angle is also investigated. These measurements extend beyond previous experimental work (Chapter 5), and do not agree with theoretical predictions. All the features can be accounted for by a careful treatment of air showers initiated by primary particles of mass greater than ten (Chapter 6), provided the multiplicity of pions follows an E (^0.5) law for high energy. The average heights of origin of muons of various momenta are determined by two different methods. It is further shown that the muons originate at heights compatible with the modified model (Chapter 7). The implications of these observations are discussed in Chapter 8 and, finally, experiments are suggested which might confirm the proposed model

Implementation of the National Health Service Abdominal Aortic Aneurysm Screening Program in England

The National Health Service Abdominal Aortic Aneurysm Screening Program (NAAASP) has been introduced after research and analysis of data from a number of randomized trials and existing local screening programs in England that showed a reduction in aneurysm-related mortality when men aged ≥65 years were offered ultrasound screening. The evidence was assessed by the United Kingdom National Screening Committee against a set of internationally recognized criteria that confirmed that screening all men aged ≥65 years saves lives. The introduction of abdominal aortic aneurysm (AAA) screening to men aged 65 years is estimated to reduce premature death from ruptured AAAs by up to 50% over the next 10 years. This article describes the AAA screening program in England, its ongoing implementation and current challenges, and outcomes in the first 150,000 men

Content provisioning based on aesthetic qualities

A portion of content rendered on many websites is often provided by third parties, different from the website provider, which leads to a mix of different content styles. Examples of third-party content include advertisements, social media widgets, etc. In some cases, e.g., native advertising, third-party content is stylized to better fit the place of display within a webpage. However, many advertisers stipulate that their ads be displayed only if not modified substantially, or not modified at all. On the other hand, publishers try to achieve aesthetic uniformity across third-party and native content on their websites. This mismatch between publisher and advertiser preferences leads to the advertiser reaching a smaller audience and the publisher having unsold inventory, translating to lower ad revenue. This disclosure presents techniques that enable publishers and advertisers to match the aesthetics of their respective content. Aesthetically appropriate ads are displayed on publisher websites without necessitating modification of the ad as submitted by the advertiser

Content delivery adjusted based on user attention

Online content delivery is often personalized based on a user’s profile and characteristics or other relevant contextual factors. Such personalization is typically predetermined and not adjusted in real-time as a user interacts with the content. With user permission, the techniques of this disclosure utilize real-time signals regarding the user’s engagement with content and adjust content delivery to fit the engagement patterns of the user, thus better matching user expectations

Viscous instabilities in flowing foams: A Cellular Potts Model approach

The Cellular Potts Model (CPM) succesfully simulates drainage and shear in foams. Here we use the CPM to investigate instabilities due to the flow of a single large bubble in a dry, monodisperse two-dimensional flowing foam. As in experiments in a Hele-Shaw cell, above a threshold velocity the large bubble moves faster than the mean flow. Our simulations reproduce analytical and experimental predictions for the velocity threshold and the relative velocity of the large bubble, demonstrating the utility of the CPM in foam rheology studies.Comment: 10 pages, 3 figures. Replaced with revised version accepted for publication in JSTA

The Fluctuations of the Quark Number and of the Chiral Condensate

The distributions of the quark number and chiral condensate over the gauge fields are computed for QCD in Euclidean space at nonzero quark chemical potential. As both operators are non-hermitian the distributions are in the complex plane. Moreover, because of the sign problem, the distributions are not real and positive. The computations are carried out within leading order chiral perturbation theory and give a direct insight into the delicate cancellations that take place in contributions to the total baryon number and the chiral condensate.Comment: 19 pages, 2 figure

Stiffness and energy losses in cylindrically symmetric superconductor levitating systems

Stiffness and hysteretic energy losses are calculated for a magnetically levitating system composed of a type-II superconductor and a permanent magnet when a small vibration is produced in the system. We consider a cylindrically symmetric configuration with only vertical movements and calculate the current profiles under the assumption of the critical state model. The calculations, based on magnetic energy minimization, take into account the demagnetization fields inside the superconductor and the actual shape of the applied field. The dependence of stiffness and hysteretic energy losses upon the different important parameters of the system such as the superconductor aspect ratio, the relative size of the superconductor-permanent magnet, and the critical current of the superconductor are all systematically studied. Finally, in view of the results, we provide some trends on how a system such as the one studied here could be designed in order to optimize both the stiffness and the hysteretic losses.Comment: 8 pages; 8 figure

Surgical infection

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