Bifurcation analysis near the cessation of complete chatter and Shilnikov homoclinic trajectories in a pressure relief valve model

This thesis investigates bifurcations associated with periodic orbits with complete chatter, as well as bifurcations associated with homoclinic trajectories, in the dynamics of a pressure relief valve model. A combination of original numerical implementations with analytical tools found in the existing literature enables a deeper understanding of the dependence of the valve dynamics on system parameters. In particular, the transition from complete to incomplete chatter along a family of periodic orbits is explored to find a cascade of bifurcations that are then investigated further using a discrete-time approximation to the system dynamics. In addition, a toolbox that formulates a boundary value problem associated with a complete chatter sequence is developed within the computational framework of the continuation package coco. Lastly, a Shilnikov-type homoclinic bifurcation is located and the global manifold structure near this bifurcation point is explored using continuation methods applied to appropriate boundary value problems

Genetic diversity between mouse strains allows identification of the CC027/GeniUnc strain as an orally reactive model of peanut allergy

Background: Improved animal models are needed to understand the genetic and environmental factors that contribute to food allergy. Objective: We sought to assess food allergy phenotypes in a genetically diverse collection of mice. Methods: We selected 16 Collaborative Cross (CC) mouse strains, as well as the classic inbred C57BL/6J, C3H/HeJ, and BALB/cJ strains, for screening. Female mice were sensitized to peanut intragastrically with or without cholera toxin and then challenged with peanut by means of oral gavage or intraperitoneal injection and assessed for anaphylaxis. Peanut-specific immunoglobulins, T-cell cytokines, regulatory T cells, mast cells, and basophils were quantified. Results: Eleven of the 16 CC strains had allergic reactions to intraperitoneal peanut challenge, whereas only CC027/GeniUnc mice reproducibly experienced severe symptoms after oral food challenge (OFC). CC027/GeniUnc, C3H/HeJ, and C57BL/6J mice all mounted a T H 2 response against peanut, leading to production of IL-4 and IgE, but only the CC027/GeniUnc mice reacted to OFC. Orally induced anaphylaxis in CC027/GeniUnc mice was correlated with serum levels of Ara h 2 in circulation but not with allergen-specific IgE or mucosal mast cell protease 1 levels, indicating systemic allergen absorption is important for anaphylaxis through the gastrointestinal tract. Furthermore, CC027/GeniUnc, but not C3H/HeJ or BALB/cJ, mice can be sensitized in the absence of cholera toxin and react on OFC to peanut. Conclusions: We have identified and characterized CC027/GeniUnc mice as a strain that is genetically susceptible to peanut allergy and prone to severe reactions after OFC. More broadly, these findings demonstrate the untapped potential of the CC population in developing novel models for allergy research

Patient Access to U.S. Physicians Who Conduct Internet or E-mail Consults

BACKGROUND: E-mail communication has the potential to improve communication between patients and doctors. OBJECTIVE: The objective of the study is to describe the access of patients to physicians who conduct e-mail consults. METHODS: We analyzed data from the National Ambulatory Medical Care Survey (NAMCS), a nationally representative cross-sectional survey of office-based physician visits, in 2001, 2002, and 2003. The main outcome measure was the percentage of visits to a provider who reported doing internet or e-mail consults. RESULTS: There was fewer than 1 in 10 outpatient visits in 2001 (9.2%) to physicians who reported doing internet or e-mail consults, and this did not increase in 2002 (5.8%) or 2003 (5.5%). Access to these physicians was greater among patients who were male, nonminority, lived in the Western United States, seen for pre-/postoperative care, seen by a primary care provider, and not seen by a nurse during their visit. Access to physicians who conducted internet or e-mail consults was independent of other patient (e.g., chronic conditions), provider (e.g., office setting), and visit (e.g., medications prescribed) characteristics. CONCLUSIONS: Access to physicians who do internet or e-mail consults is generally low and did not increase between 2001 and 2003, despite growth in internet access and in other internet-related activities

Current and Future Drug Targets in Weight Management

Obesity will continue to be one of the leading causes of chronic disease unless the ongoing rise in the prevalence of this condition is reversed. Accumulating morbidity figures and a shortage of effective drugs have generated substantial research activity with several molecular targets being investigated. However, pharmacological modulation of body weight is extremely complex, since it is essentially a battle against one of the strongest human instincts and highly efficient mechanisms of energy uptake and storage. This review provides an overview of the different molecular strategies intended to lower body weight or adipose tissue mass. Weight-loss drugs in development include molecules intended to reduce the absorption of lipids from the GI tract, various ways to limit food intake, and compounds that increase energy expenditure or reduce adipose tissue size. A number of new preparations, including combinations of the existing drugs topiramate plus phentermine, bupropion plus naltrexone, and the selective 5-HT2C agonist lorcaserin have recently been filed for approval. Behind these leading candidates are several other potentially promising compounds and combinations currently undergoing phase II and III testing. Some interesting targets further on the horizon are also discussed

Contextualizing Game Literacy : A transhistorical approach to understanding Game-Based Learning environments

The nature of ‘reading’ different types of texts, across all media, is fundamentally beholden to the concept of ‘literacy’. The concept of literacy is well established in media studies – from books, to film, and visual, performing and interactive arts – and as such it has a wide range of applicability. All forms of media constitute a semiotic milieu in which signifiers and codes mean different things depending on the form’s unique language and the contexts and manner in which individual participants, or “readers”, approach them. In the field of digital games research, literacy is commonly defined as a narrower concept that refers to the ability to identify affordances and interact with game components with a high degree of confidence. This focus on capability is understandable to a degree: the unique aspect of games as a medium is often considered to specifically be its interactability, and thus being able to interact becomes synonymous with being ‘game literate’. In this paper, however, we will both describe how literacy in games would benefit from a more nuanced, transhistorical view of interactability, as well as provide examples from many kinds of media beyond games to demonstrate that interaction literacy is neither novel nor unique to the medium of games. Understanding this rich history would provide a broader foundation of referential literature for game scholars to use when discussing the concept of game literacy and the interactability of media in general.Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for third-party components of this work must be honored. For all other uses, contact the owner/author(s).</p