484 research outputs found
Paper Session I-B - The Invention, Development and Commercialization of a Non-Invasive Intracranial Pressure Monitor
Defining the Problem - Why is a non-invasive intracranial pressure monitor needed?
The monitoring of intracranial pressure and pressure volume index is of significant diagnostic and post-operative importance for many patients with cranial injuries and for patients who have undergone brain surgery. Cranial injuries often affect the pressure of the subarachnoidal fluid around the brain. Abnormally elevated intracranial pressure (ICP) occurs in about 60% of patients with head trauma. When ICP increases above 20mmHg, a 95% death rate occurs. High ICP reduces blood flow to the brain, preventing oxygen and nutrients from reaching brain tissue. This starvation results in the death of brain tissue
Determining Wastewater User Service Charge Rates
Good financial management is a critical part of all wastewater operations. It allows you to establish the user service charge rates necessary to keep your utility financially healthy and running smoothly. This publication was designed to help small to medium-sized wastewater utility operations decide how much they should be charging their residential, commercial, and industrial customers for wastewater services. It includes a Lotus 1-2-3 computer model program and manual procedures to help you calculate specific values for your system\u27s user service charges. [The computer program referenced throughout this document is not available.
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Conceptualization and Empirical Definition of Time Perspective
The primary purpose of this thesis is to determine whether or not time perspective can be represented by a relatively simple unitary measure in the form of a questionnaire. More specifically, the aim is to determine whether or not time perspective can be represented as a scalable attitude in accordance with the Guttman scalogram model
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Indoor Particulate Matter during HOMEChem: Concentrations, Size Distributions, and Exposures.
It is important to improve our understanding of exposure to particulate matter (PM) in residences because of associated health risks. The HOMEChem campaign was conducted to investigate indoor chemistry in a manufactured test house during prescribed everyday activities, such as cooking, cleaning, and opening doors and windows. This paper focuses on measured size distributions of PM (0.001-20 ÎŒm), along with estimated exposures and respiratory-tract deposition. Number concentrations were highest for sub-10 nm particles during cooking using a propane-fueled stovetop. During some cooking activities, calculated PM2.5 mass concentrations (assuming a density of 1 g cm-3) exceeded 250 ÎŒg m-3, and exposure during the postcooking decay phase exceeded that of the cooking period itself. The modeled PM respiratory deposition for an adult residing in the test house kitchen for 12 h varied from 7 ÎŒg on a day with no indoor activities to 68 ÎŒg during a simulated day (including breakfast, lunch, and dinner preparation interspersed by cleaning activities) and rose to 149 ÎŒg during a simulated Thanksgiving day
Surface reservoirs dominate dynamic gas-surface partitioning of many indoor air constituents
Human health is affected by indoor air quality. One distinctive aspect of the indoor environment is its very large surface area that acts as a poorly characterized sink and source of gas-phase chemicals. In this work, air-surface interactions of 19 common indoor air contaminants with diverse properties and sources were monitored in a house using fast-response, on-line mass spectrometric and spectroscopic methods. Enhanced-ventilation experiments demonstrate that most of the contaminants reside in the surface reservoirs and not, as expected, in the gas phase. They participate in rapid air-surface partitioning that is much faster than air exchange. Phase distribution calculations are consistent with the observations when assuming simultaneous equilibria between air and large weakly polar and polar absorptive surface reservoirs, with acid-base dissociation in the polar reservoir. Chemical exposure assessments must account for the finding that contaminants that are fully volatile under outdoor air conditions instead behave as semivolatile compounds indoors
A North Atlantic tephrostratigraphical framework for 130-60 ka b2k:new tephra discoveries, marine-based correlations, and future challenges
Building chronological frameworks for proxy sequences spanning 130â60 ka b2k is plagued by difficulties and uncertainties. Recent developments in the North Atlantic region, however, affirm the potential offered by tephrochronology and specifically the search for cryptotephra. Here we review the potential offered by tephrostratigraphy for sequences spanning 130â60 ka b2k. We combine newly identified cryptotephra deposits from the NGRIP ice-core and a marine core from the Iceland Basin with previously published data from the ice and marine realms to construct the first tephrostratigraphical framework for this time-interval. Forty-three tephra or cryptotephra deposits are incorporated into this framework; twenty three tephra deposits are found in the Greenland ice-cores, including nine new NGRIP tephras, and twenty separate deposits are preserved in various North Atlantic marine sequences. Major, minor and trace element results are presented for the new NGRIP horizons together with age estimates based on their position within the ice-core record. Basaltic tephras of Icelandic origin dominate the framework with only eight tephras of rhyolitic composition found. New results from marine core MD99-2253 also illustrate some of the complexities and challenges of assessing the depositional integrity of marine cryptotephra deposits. Tephra-based correlations in the marine environment provide independent tie-points for this time-interval and highlight the potential of widening the application of tephrochronology. Further investigations, however, are required, that combine robust geochemical fingerprinting and a rigorous assessment of tephra depositional processes, in order to trace coeval events between the two depositional realms
A complex systems approach to constructing better models for managing financial markets and the economy
We outline a vision for an ambitious program to understand the economy and financial markets as a complex evolving system of coupled networks of interacting agents. This is a completely different vision from that currently used in most economic models. This view implies new challenges and opportunities for policy and managing economic crises. The dynamics of such models inherently involve sudden and sometimes dramatic changes of state. Further, the tools and approaches we use emphasize the analysis of crises rather than of calm periods. In this they respond directly to the calls of Governors Bernanke and Trichet for new approaches to macroeconomic modelling.The publication of this work was partially supported by the European Unionâs Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 284709, a Coordination and Support Action in the Information and Communication Technologies activity area (âFuturICTâ FET Flagship Pilot Project). Doyne Farmer, Mauro Gallegati and Cars Hommes also acknowledge financial support from the EU-7th framework collaborative project âComplexity Research Initiative for Systemic InstabilitieS (CRISIS)â, grant No. 288501. Cars Hommes acknowledges financial support from the Netherlands Organization for Scientific Research (NWO), project âUnderstanding Financial Instability through Complex Systemsâ. None of the above are responsible for errors in this paper.Publicad
Mutant Neurogenin-3 in congenital malabsorptive diarrhea
Background: Neurogenin-3 (NEUROG3) is expressed in endocrine progenitor cells and is required for endocrine-cell development in the pancreas and intestine. The NEUROG3 gene (NEUROG3) is therefore a candidate for the cause of a newly discovered autosomal recessive disorder characterized by generalized malabsorption and a paucity of enteroendocrine cells. Methods: We screened genomic DNA from three unrelated patients with sparse enteroendocrine cells for mutations of NEUROG3. We then tested the ability of the observed mutations to alter NEUROG3 function, using in vitro and in vivo assays. Results: The patients had few intestinal enteroendocrine cells positive for chromogranin A, but they had normal numbers of Paneth\u27s, goblet, and absorptive cells. We identified two homozygous mutations in NEUROG3, both of which rendered the NEUROG3 protein unable to activate NEUROD1, a downstream target of NEUROG3, and compromised the ability of NEUROG3 to bind to an E-box element in the NEUROD1 promoter. The injection of wild-type but not mutant NEUROG3 messenger RNA into xenopus embryos induced NEUROD1 expression. Conclusions: A newly discovered disorder characterized by malabsorptive diarrhea and a lack of intestinal enteroendocrine cells is caused by loss-of-function mutations in NEUROG3. Copyright © 2006 Massachusetts Medical Society
Next Generation Nuclear Plant Methods Technical Program Plan
One of the great challenges of designing and licensing the Very High Temperature Reactor (VHTR) is to confirm that the intended VHTR analysis tools can be used confidently to make decisions and to assure all that the reactor systems are safe and meet the performance objectives of the Generation IV Program. The research and development (R&D) projects defined in the Next Generation Nuclear Plant (NGNP) Design Methods Development and Validation Program will ensure that the tools used to perform the required calculations and analyses can be trusted. The Methods R&D tasks are designed to ensure that the calculational envelope of the tools used to analyze the VHTR reactor systems encompasses, or is larger than, the operational and transient envelope of the VHTR itself. The Methods R&D focuses on the development of tools to assess the neutronic and thermal fluid behavior of the plant. The fuel behavior and fission product transport models are discussed in the Advanced Gas Reactor (AGR) program plan. Various stress analysis and mechanical design tools will also need to be developed and validated and will ultimately also be included in the Methods R&D Program Plan. The calculational envelope of the neutronics and thermal-fluids software tools intended to be used on the NGNP is defined by the scenarios and phenomena that these tools can calculate with confidence. The software tools can only be used confidently when the results they produce have been shown to be in reasonable agreement with first-principle results, thought-problems, and data that describe the âhighly rankedâ phenomena inherent in all operational conditions and important accident scenarios for the VHTR
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