7,659 research outputs found
Lognormal scale invariant random measures
In this article, we consider the continuous analog of the celebrated
Mandelbrot star equation with lognormal weights. Mandelbrot introduced this
equation to characterize the law of multiplicative cascades. We show existence
and uniqueness of measures satisfying the aforementioned continuous equation;
these measures fall under the scope of the Gaussian multiplicative chaos theory
developed by J.P. Kahane in 1985 (or possibly extensions of this theory). As a
by product, we also obtain an explicit characterization of the covariance
structure of these measures. We also prove that qualitative properties such as
long-range independence or isotropy can be read off the equation.Comment: 31 pages; Probability Theory and Related Fields (2012) electronic
versio
Gaussian multiplicative Chaos for symmetric isotropic matrices
Motivated by isotropic fully developed turbulence, we define a theory of
symmetric matrix valued isotropic Gaussian multiplicative chaos. Our
construction extends the scalar theory developed by J.P. Kahane in 1985
Managing Complexity with the Department of Defense Architecture Framework: Development of a Dynamic System Architecture Model
Architecture frameworks are tools for managing system complexity by structuring data in a common language and format. By characterizing the form, function, and rules governing systems, architecture frameworks serve as a communication tool to stakeholder communities with different views of the system and facilitate comparative evaluation across architectures. The goal of this research is to explore the applicability of architecture frameworks to the study of emergent properties of satellites. The U.S. Department of Defense Architecture Framework was selected to achieve this goal given its orientation towards technical systems in contrast to the majority of architecture frameworks focused on business enterprises. Although developed by military planners in the 1990âs to support the acquisition of interoperable information systems, the Department of Defense Architecture Framework can be used to connect operational concepts and capabilities to the technical architecture of any system. While the views of the Department of Defense Architecture Framework are well-defined, little guidance is provided on how the views are to be constructed. Vitech Corporationâs software program CORE,Âź a systems engineering modeling tool with the ability rapidly to produce architecture views from a common data repository, was employed to complete Department of Defense Architecture Frameworks for the Hubble Space Telescope.
Upon characterizing Hubble within this common structure, the value of the Department of Defense Architecture Framework for conducting dynamic quantitative analyses of system architectures was explored. A methodology is proposed and tested for evaluating human and robotic architectures for on-orbit servicingâthe extension of the useful life of spacecraft through refueling, upgrading, repair, relocation, et al. In particular, a multi-year servicing campaign is modeled for Hubble including behavioral threads that characterize the Orbiting Observatory, servicing architecture, and science customers. Preliminary results indicate that, when coupled with an executable model, the Department of Defense Architecture Framework can be utilized for dynamic quantitative evaluation of space system architectures. The paper concludes with lessons learned from using the Department of Defense Architecture Framework and proposes improvements for the application of its static views to model-based systems engineering
Helioseismology, solar models and solar neutrinos
We review recent advances concerning helioseismology, solar models and solar
neutrinos. Particularly we shall address the following points: i) helioseismic
tests of recent SSMs; ii)the accuracy of the helioseismic determination of the
sound speed near the solar center; iii)predictions of neutrino fluxes based on
helioseismology, (almost) independent of SSMs; iv)helioseismic tests of exotic
solar models.Comment: 11 pages with 6 ps figures included, procsla style, based on the
talks presented at Neutrino Telescopes '99, Venice, February 1999, and at
Valencia '99, Valencia, May 1999, to appear in the proceeding
Nicotine Enemas for Active Crohn's Colitis: An Open Pilot Study
Background. Smoking has a detrimental effect in Crohn's disease (CD), but this may be due to factors in smoking other than nicotine. Given that transdermal nicotine benefits ulcerative colitis (UC), and there is a considerable overlap in the treatment of UC and CD, the possible beneficial effect of nicotine has been examined in patients with Crohn's colitis. Aims. To assess the efficacy and safety of nicotine enemas in active Crohn's colitis. Patients. Thirteen patients with active rectosigmoid CD; 3 patients were excluded because they received antibiotics.
Methods. Subjects were given 6 mg nicotine enemas, each day for 4 weeks, in an open pilot study. At the beginning and end of the trial, a Crohn's disease activity index (CDAI) score was calculated, sigmoidoscopy was performed, and haematological inflammatory markers measured.
Results. Mean CDAI decreased from 202 to 153âthe score was reduced in 6 patients, unchanged in 3, and increased in one. Frequency of bowel movements decreased in 8 patients and the sigmoidoscopy grade was reduced in 7. Mean C-reactive protein decreased from 22.0 to 12.3 mg/L. There were no withdrawals due to adverse events.
Conclusions. In this relatively small study of patients with active Crohn's colitis, 6 mg nicotine enemas appeared to be of clinical benefit in most patients. They were well tolerated and safe
Pittsburgh\u27s Mt. Lebanon Tunnels- Case History
Discussions of basic design philosophy and comparison of alternative contract bid options are presented. Also discussed are descriptions of field monitoring activities with respect to the construction methods, ground response, installation of materials and their performance. Finally, conclusions are reached relative to the NATM philosophy as applied to this project and its place as a design process within the context of United States underground construction practice
Deliberate Exercise of Pregnant Holstein Heifers Improves Milk Composition During Lactation
Exercise has substantial impacts on systemic physiology, but little research has been conducted to assess how it may influence dairy cattle in modern confined production systems. Dairy heifers were walked for up to 45 minutes, 4 days per week for 8 weeks during pregnancy to assess impacts on subsequent health and productivity. Heifers that were exercised had increased milk protein and solids-not-fat concentrations for up to 15 weeks into lactation, and increased milk fat and energy-corrected milk production at some time points during this period, as compared to sedentary contemporaries. No adverse or beneficial effects of exercise were found on locomotion, calving ease, date of parturition, or somatic cell scores. These findings point to potential impacts on lactation productivity following exercise in pregnant heifers
Post-Foucauldian governmentality: what does it offer critical social policy analysis?
This article considers the theoretical perspective of post-Foucauldian governmentality, especially the insights and challenges it poses for applied researchers within the critical social policy tradition. The article firstly examines the analytical strengths of this approach to understanding power and rule in contemporary society, before moving on to consider its limitations for social policy. It concludes by arguing that these insights can be retained, and some of the weaknesses overcome, by adopting a ârealist governmentalityâ approach (Stenson 2005, 2008). This advocates combining traditional discursive analysis with more ethnographic methods in order to render visible the concrete activity of governing, and unravel the messiness, complexity and unintended consequences involved in the struggles around subjectivity
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