98 research outputs found
Size Relationships of Big History Objects: From the Universe to the Atomic Nucleus
Big History involves a variety of sizes from the atomic nucleus to the size of the universe. How can we make sense of this? A popular video (Eames 1977) about the power of 10 took a “picture” for every factor of 10 in distance with over 40 “stops” from a nucleus (not even the smallest distance we can talk about) to the edge of the universe. Instead, we will explore just nine steps in distances of things we know about: the atomic nucleus, the atom, a bacterium, a human, the Earth, the distance to the sun, the distance to the closest star, the size of the galaxy, and the size of the universe. Quite amazingly, many of these distances can be estimated with only a few fundamental physics constants. Also, the ratio of the distances of the larger to the next smaller is about the same (with some exceptions): about 150,000. How can this factor of 150,000 be visualized? It is about the ratio of a commercial jet’s height compared to your palm, or, using the American standard unit of a football field, the smaller distance would be about 1/32 of an inch
An Exploration of Historical Transitions with Simple Analogies and Empirical Event Rates
Various qualitative models have been suggested for major historical social and technological transitions. Many of these transitions still have puzzling aspects such as the early transition from hunter-gatherer to agriculturally-based society which required dramatically increased effort. Another puzzle is the emergence of the scientific and industrial revolution in Europe despite many previous similar discoveries in other regions. Explorations of simple models with aggregate, dynamic, and nonlinear processes might lead to insights of the unique aspects of each transition. Topics include the transitions between hunter-gatherers, agricultural societies, early civilizations, market development, capitalism, industrialization, and sustainable societies with factors of land-pressures, economies of scale, suppressed growth, and chain reactions.Many types of models could be applied to these transitions. First, basic characteristics, such as width and midpoint of the transitions, are determined by analyzing historical events contributing to the transition. However, this does give much insight into the dynamics or parameters of the transition. For more understanding, each of six transitions is explored with a simple phenomenological model. These simplified models do not attempt to quantitatively address the details of the actual historical mechanisms Instead analogies to more natural systems are invoked to gain insights
Factors affecting the initiation of a shared decision making program in obstetric practices
As healthcare systems progress toward initiatives that increase patient engagement, stake-holder hopes are that shared decision making (SDM) will become routine practice. Yet, there is limited empirical evidence to guide such SDM program implementations, particularly in obstetric practices. The first stage of any project implementation is the “initiation stage”, in which project leaders define a project’s purpose and stakeholders and structures are put in place to support the new initiative. Our study’s objective was to identify factors affecting the initiation stage of an SDM program implementation project for TOLAC, trial of labor after Cesarean. We conducted a multiple-case study of an SDM program implementation in three obstetric settings in Washington State. The research design and analysis were guided by implementation science frameworks and project management literature. Data sources included interviews with key informants from the State, SDM tool vendors, and three project sites, as well as implementation documents. The study results provide insight into how the identified project implementation factors provide an essential foundation for informing project planning, execution, and reflection/evaluation. In this study, the State’s decision aid certification program pressured the project sites to shape the project purpose and engage stakeholders that would meet immediate project requirements (specifically, state require-ments). The study reveals that external demands may not be in perfect alignment with the internal necessities required for an SDM program’s long-term viability and sustainability. Findings may be used by implementers and researchers to model and strategize the early stages of SDM program implementation projects, particularly in the obstetric setting
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RISKIND: An enhanced computer code for National Environmental Policy Act transportation consequence analysis
The RISKIND computer program was developed for the analysis of radiological consequences and health risks to individuals and the collective population from exposures associated with the transportation of spent nuclear fuel (SNF) or other radioactive materials. The code is intended to provide scenario-specific analyses when evaluating alternatives for environmental assessment activities, including those for major federal actions involving radioactive material transport as required by the National Environmental Policy Act (NEPA). As such, rigorous procedures have been implemented to enhance the code`s credibility and strenuous efforts have been made to enhance ease of use of the code. To increase the code`s reliability and credibility, a new version of RISKIND was produced under a quality assurance plan that covered code development and testing, and a peer review process was conducted. During development of the new version, the flexibility and ease of use of RISKIND were enhanced through several major changes: (1) a Windows{sup {trademark}} point-and-click interface replaced the old DOS menu system, (2) the remaining model input parameters were added to the interface, (3) databases were updated, (4) the program output was revised, and (5) on-line help has been added. RISKIND has been well received by users and has been established as a key component in radiological transportation risk assessments through its acceptance by the U.S. Department of Energy community in recent environmental impact statements (EISs) and its continued use in the current preparation of several EISs
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RESRAD connection for facilitating MARSSIM analysis : an illustration of applying the OpenLink concept.
The focus of this work is to more tightly integrate tools traditionally used in MARSSIM (Multi-Agency Radiation Survey and Site Investigation Manual) final status survey design. MARSSIM provides guidance on appropriate methodologies for establishing that dose or risk-based standards for a site contaminated with radionuclides have been achieved. RESidual RADioactive (RESRAD) codes are used by the U.S. Department of Energy, the U.S. Nuclear Regulatory Commission, and other federal agencies to convert dose-based cleanup criteria to site-specific-derived concentration guideline level (DCGL) requirements. By implementing MARSSIM concepts directly within RESRAD, users can now directly generate site-specific DCGL requirements and associated area factors
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Applications of RESRAD family of computer codes to sites contaminated with radioactive residues.
The RESIL4D family of computer codes was developed to provide a scientifically defensible answer to the question ''How clean is clean?'' and to provide useful tools for evaluating human health risk at sites contaminated with radioactive residues. The RESRAD codes include (1) RESRAD for soil contaminated with radionuclides; (2) RESRAD-BUILD for buildings contaminated with radionuclides; (3) RESRAD-CHEM for soil contaminated with hazardous chemicals; (4) RESRAD-BASELINE for baseline risk assessment with measured media concentrations of both radionuclides and chemicals; (5) RESRAD-ECORISK for ecological risk assessment; (6) RESRAD-RECYCLE for recycle and reuse of radiologically contaminated metals and equipment; and (7) RESRAD-OFFSITE for off-site receptor radiological dose assessment. Four of these seven codes (RESRAD, RESRAD-BUILD, RESRAD-RECYCLE, and RESRAD-OFFSITE) also have uncertainty analysis capabilities that allow the user to input distributions of parameters. RESRAD has been widely used in the United States and abroad and approved by many federal and state agencies. Experience has shown that the RESRAD codes are useful tools for evaluating sites contaminated with radioactive residues. The use of RESRAD codes has resulted in significant savings in cleanup cost. Analysis of 19 site-specific uranium guidelines is discussed in the paper
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User's manual for RESRAD version 6.
This manual provides information on the design and application of the RESidual RADioactivity (RESRAD) code. It describes the basic models and parameters used in the RESRAD code to calculate doses and risks from residual radioactive materials and the procedures for applying these models to calculate operational guidelines for soil contamination. RESRAD has undergone many improvements to make it more realistic in terms of the models used in the code and the parameters used as defaults. Version 6 contains a total of 145 radionuclides (92 principal and 53 associated radionuclides), and the cutoff half-life for associated radionuclides has been reduced to 1 month. Other major improvements to the RESRAD code include its ability to run uncertainty analyses, additional options for graphical and text output, a better dose conversion factor editor, updated databases, a better groundwater transport model for long decay chains, an external ground radiation pathway model, an inhalation area factor model, time-integration of dose and risk, and a better graphical user interface. In addition, RESRAD has been benchmarked against other codes in the environmental assessment and site cleanup arena, and RESRAD models have been verified and validated
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Environmental impacts of options for disposal of depleted uranium tetrafluoride (UF{sub 4}).
The U.S. Department of Energy (DOE) evaluated options for managing its depleted uranium hexafluoride (UF{sub 6}) inventory in the Programmatic Environmental Impact Statement for the Long-Term Management and Use of Depleted Uranium Hexafluoride (PEIS) of April 1999. Along with the impacts from other management options, the PEIS discussed the environmental impacts from the disposal of depleted uranium oxide, which could result from the chemical conversion of depleted UF{sub 6}. It has been suggested that the depleted UF{sub 6} could also be converted to uranium tetrafluoride (UF{sub 4}) and disposed of. This report considers the potential environmental impacts from the disposal of DOE's depleted UF{sub 6} inventory after its conversion to UF{sub 4}. The impacts were evaluated for the same three disposal facility options that were considered in the PEIS for uranium oxide: shallow earthen structures, belowground vaults, and mines. They were evaluated for a dry environmental setting representative of the western United States. To facilitate comparisons and future decision making, the depleted UF{sub 4} disposal analyses performed and the results presented in this report are at the same level of detail as that in the PEIS
Verificação do funcionamento de derivações ventrĂculo-peritoneais com válvula mediante emprego de radioisĂłtopos: contribuição tĂ©cnica pessoal
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