8,536 research outputs found
Associations of neighborhood characteristics with active park use : an observational study in two cities in the USA and Belgium
Background: Public parks can be an important setting for physical activity promotion, but to increase park use and the activity levels of park users, the crucial attributes related to active park use need to be defined. Not only user characteristics and structural park attributes, but also characteristics of the surrounding neighborhood are important to examine. Furthermore, internationally comparable studies are needed, to find out if similar intervention strategies might be effective worldwide. The main aim of this study was to examine whether the overall number of park visitors and their activity levels depend on study site, neighborhood walkability and neighborhood income.
Methods: Data were collected in 20 parks in Ghent, Belgium and San Diego, USA. Two trained observers systematically coded park characteristics using the Environmental Assessment of Public Recreation Spaces (EAPRS) tool, and park user characteristics using the System for Observing Play and recreation in Communities (SOPARC) tool. Multilevel multiple regression models were conducted in MLwiN 2.25.
Results: In San Diego parks, activity levels of park visitors and number of vigorously active visitors were higher than in Ghent, while the number of visitors walking and the overall number of park visitors were lower. Neighborhood walkability was positively associated with the overall number of visitors, the number of visitors walking, number of sedentary visitors and mean activity levels of visitors. Neighborhood income was positively associated with the overall number of visitors, but negatively with the number of visitors being vigorously active.
Conclusions: Neighborhood characteristics are important to explain park use. Neighborhood walkability-related attributes should be taken into account when promoting the use of existing parks or creating new parks. Because no strong differences were found between parks in high-and low-income neighborhoods, it seems that promoting park use might be a promising strategy to increase physical activity in low-income populations, known to be at higher risk for overweight and obesity
Probabilistic Solar Energetic Particle Models
To plan and design safe and reliable space missions, it is necessary to take into account the effects of the space radiation environment. This is done by setting the goal of achieving safety and reliability with some desired level of confidence. To achieve this goal, a worst-case space radiation environment at the required confidence level must be obtained. Planning and designing then proceeds, taking into account the effects of this worst-case environment. The result will be a mission that is reliable against the effects of the space radiation environment at the desired confidence level. In this paper we will describe progress toward developing a model that provides worst-case space radiation environments at user-specified confidence levels. We will present a model for worst-case event-integrated solar proton environments that provide the worst-case differential proton spectrum. This model is based on data from IMP-8 and GOES spacecraft that provide a data base extending from 1974 to the present. We will discuss extending this work to create worst-case models for peak flux and mission-integrated fluence for protons. We will also describe plans for similar models for helium and heavier ions
Human Exploration of the Moon and Mars: Space Radiation Data, Modeling and Instrumentation Needs
On January 14, 2004 President Bush announced the Vision for Space Exploration, a program for long-term human and robotic exploration of the solar system which will include a return of humans to the moon not later than 2020, followed by human missions to Mars. Since this announcement, NASA has been developing plans and mission architectures for these human missions as well as robotic precursor missions. Among the critical needs for research and development in support of this Vision are investigations on the ionizing radiation environment and development of instrumentation to guide NASA in managing the radiation exposure of the crew during the manned missions. For mission planning, models are needed for a reference worst-case solar energetic particle event and a reference worst-case galactic cosmic ray environment. During Lunar missions it will be necessary to carefully manage the radiation exposure of the crew in real time because of the variability of the radiation environment due to solar activity. In particular, prompt warnings will be needed when large solar energetic particle events occur. Accurate predictions will also be needed of the particle flux and flux history at the moon to support critical mission management decisions. A new generation of dosimeters and radiation monitors will also be needed to accompany the crew. These instruments must return data in real time so that they can be used in the critical decisions that must be made if a large solar energetic particle event occurs. This is especially true if it occurs during a lunar excursion. A substantial radiation exposure on extended lunar missions and Mars missions comes from galactic cosmic rays. This exposure must be mitigated by radiation shielding and other measures. During Mars missions the galactic cosmic ray exposure occurs primarily during the cruse phase between the Earth and Mars. This is especially true for opposition class missions. These missions would typically last -430 days with only 30-90 days on Mars. Solar energetic particle events are less of a concern on Mars because of its greater distance from the Sun (approximately 1.5 AU) and the partial protection afforded by its atmosphere (approximately 20 grams per square centimeter). The talk will describe the current plans for future human missions to Earth orbit, the Moon and Mars. The needs for data and models of the radiation environment and radiation detectors to support these missions will be discussed
Probabilistic Models for Solar Particle Events
Probabilistic Models of Solar Particle Events (SPEs) are used in space mission design studies to provide a description of the worst-case radiation environment that the mission must be designed to tolerate.The models determine the worst-case environment using a description of the mission and a user-specified confidence level that the provided environment will not be exceeded. This poster will focus on completing the existing suite of models by developing models for peak flux and event-integrated fluence elemental spectra for the Z>2 elements. It will also discuss methods to take into account uncertainties in the data base and the uncertainties resulting from the limited number of solar particle events in the database. These new probabilistic models are based on an extensive survey of SPE measurements of peak and event-integrated elemental differential energy spectra. Attempts are made to fit the measured spectra with eight different published models. The model giving the best fit to each spectrum is chosen and used to represent that spectrum for any energy in the energy range covered by the measurements. The set of all such spectral representations for each element is then used to determine the worst case spectrum as a function of confidence level. The spectral representation that best fits these worst case spectra is found and its dependence on confidence level is parameterized. This procedure creates probabilistic models for the peak and event-integrated spectra
Tuning and controlling gene expression noise in synthetic gene networks
Synthetic gene networks can be used to control gene expression and cellular phenotypes in a variety of applications. In many instances, however, such networks can behave unreliably due to gene expression noise. Accordingly, there is a need to develop systematic means to tune gene expression noise, so that it can be suppressed in some cases and harnessed in others, e.g. in cellular differentiation to create population-wide heterogeneity. Here, we present a method for controlling noise in synthetic eukaryotic gene expression systems, utilizing reduction of noise levels by TATA box mutations and noise propagation in transcriptional cascades. Specifically, we introduce TATA box mutations into promoters driving TetR expression and show that these mutations can be used to effectively tune the noise of a target gene while decoupling it from the mean, with negligible effects on the dynamic range and basal expression. We apply mathematical and computational modeling to explain the experimentally observed effects of TATA box mutations. This work, which highlights some important aspects of noise propagation in gene regulatory cascades, has practical implications for implementing gene expression control in synthetic gene networks
3. Launching the New Enterprise
As the academic year of 1945-46 approached, the intensity of activity in preparation for actually opening the school in the fall term became overwhelming. Incredible though it may seem, Ives and Day were able in a period of a few weeks to assemble the nucleus of a faculty, several of whom formed a continuing source of counsel and advice both during the school’s formative years and thereafter. Includes: The First Dean and the School’s Dedication; A Participant’s View of the Early Years; Ives Moves On; Several Views of Martin P. Catherwood; The Founders
The Ursinus Weekly, October 28, 1940
Senator J. A. Ellender holds Willkie temperamentally unfit for president • Importance of \u27but\u27 told by vespers talk • Connor calls news staff to plan for Jr. paper • Republican rally to hear Davis tomorrow evening • Rev. Mr. Faye \u2724, to speak on problems of college students • Prof. Mauchly gives lecture at conference of physicists • Hoosier prophet ventures vote prognostication • Get a mask for Friday! • Results of Berlin-Tokyo axis discussed in IRC panel talks • Meistersingers to sing at Collegeville-Trappe assembly • Minutes before, Huey and I were talking... • Campaigning with Yehudi! • Mules\u27 offensive attack swamps bears by 15-6 • Allison leads \u27Fords against bakermen, 3-0 • Rootin\u27 tootin\u27 bout slated, Nov. 5, Sam\u27s arena • Ursinus hockeyites blank Rosemont • Baker is optimistic on soccer future • English Club admits seven; discusses books for review • Joyce Ward reports plans of women\u27s archery practice • \u27Big sisters\u27 treat freshmen and co-ed transfers at movie • Pre-legals fingerprinted; hear of scientific detectionhttps://digitalcommons.ursinus.edu/weekly/1796/thumbnail.jp
CREME: The 2011 Revision of the Cosmic Ray Effects on Micro-Electronics Code
We describe a tool suite, CREME, which combines existing capabilities of CREME96 and CREME86 with new radiation environment models and new Monte Carlo computational capabilities for single event effects and total ionizing dose
Churchman\u27s Inquiring Systems: Kernel Theories for Knowledge Management
Churchman [1971] defines inquiry as an activity that produces knowledge. He examines the epistemologies of five schools of philosophy from the perspective of general systems theory, asking the question as to whether each is suitable as the basis for the design of computer-based inquiring systems. He considers systems design and design theory in some detail. We believe that Churchman\u27s inquiring systems can form the basis for the design of knowledge management systems and that the IS research community has hardly tapped the potential of inquiring systems in that regard. Mason and Mitroff [1973] brought inquiring systems into the IS literature early on, essentially making the work endogenous to the field. We argue that building on inquiring systems can contribute to developing IS as a discipline by maintaining continuity in research and developing a theory that IS can call its own. We believe that the lack of use of Churchman\u27s work may be due to its lack of visibility in recent years and attempt to remedy that by summarizing the basics of the inquirers in some detail, trying not to interpret, but to remain faithful to the original. The paper encourages readers to study the original and develop their own notion of how the inquirers might be used in knowledgemanagement work. There are probably as many different perspectives on how inquiring systems could support KMS as there are IS researchers willing to study them. We would like to encourage a proliferation of such perspectives
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