Language

State Department: Staffing and Foreign Language Shortfalls Persist Despite Initiatives to Address Gaps (open access)

State Department: Staffing and Foreign Language Shortfalls Persist Despite Initiatives to Address Gaps

Testimony issued by the Government Accountability Office with an abstract that begins "GAO has reported in recent years on a number of human capital issues that have hampered the Department of State's (State) ability to carry out U.S. foreign policy priorities and objectives, particularly at posts central to the war on terror. In 2002, State implemented the Diplomatic Readiness Initiative (DRI) to address shortfalls in the number and skills of State employees. This testimony addresses State's progress in (1) addressing staffing shortfalls since the implementation of DRI and (2) filling gaps in the language proficiency of Foreign Service officers and other staff. To accomplish these objectives, GAO analyzed staffing and language data and met with State officials."
Date: August 1, 2007
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Capitol Power Plant: Status of Utility Tunnel Projects (open access)

Capitol Power Plant: Status of Utility Tunnel Projects

Testimony issued by the Government Accountability Office with an abstract that begins "The Architect of the Capitol (AOC), through the Capitol Power Plant, operates five walkable utility tunnels containing steam and chilled water pipes associated with serving the heating and cooling requirements of the U.S. Capitol and over 20 surrounding facilities. In our work last fall, we addressed conditions in the tunnels and AOC's plans for addressing them. The Office of Compliance (OOC), which is responsible for advancing safety, health, and workplace rights in the legislative branch, and the tunnel workers had raised concerns about health and safety issues in the tunnels. As a result of these concerns, in January 2006, OOC issued citations for and asked AOC to address a potential asbestos hazard and heat stress conditions in the tunnels. In addition, in February 2006, OOC filed a complaint against AOC concerning hazards in the tunnels, including falling concrete, an inadequate communication system for these confined spaces, and inadequate escape exits (egresses). According to OOC officials, these conditions had been brought to AOC's attention by OOC inspectors as early as 1999, but AOC had not made sufficient progress in addressing them, and conditions in the tunnels had deteriorated further. …
Date: August 1, 2007
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Aviation Finance: Observations on the Current FAA Funding Structure's Support for Aviation Activities, Issues Affecting Future Costs, and Proposed Funding Changes (open access)

Aviation Finance: Observations on the Current FAA Funding Structure's Support for Aviation Activities, Issues Affecting Future Costs, and Proposed Funding Changes

Testimony issued by the Government Accountability Office with an abstract that begins "The Federal Aviation Administration (FAA) operates one of the safest air transportation systems in the world, but this system is under growing strain as the demand for air travel increases. Recognizing the need to transform this system, Congress created the Joint Planning and Development Office (JPDO), housed within FAA, to plan and develop the Next Generation Air Transportation System (NextGen). The current authorization for FAA, the Airport and Airway Trust Fund (Trust Fund), and most of the excise taxes that support the Trust Fund will expire September 30, 2007. Several proposals, including two reauthorization bills--H.R. 2881 and S. 1300--identify various funding sources for FAA activities, including NextGen. Among these are current excise taxes, fees, and flight surcharges. Concerned about the need for stable, sustainable financing for the nation's multibillion-dollar transportation infrastructure investments, including NextGen, GAO has designated transportation financing as high risk. GAO's statement addresses (1) the extent to which the current funding structure can support FAA's activities, including NextGen, (2) issues that could affect the overall cost of NextGen, and (3) the implications of selected proposals to fund aviation activities. The statement is based on recent GAO …
Date: August 1, 2007
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
A vadose zone Transport Processes Investigation within the glacial till at the Fernald Environmental Management Project. (open access)

A vadose zone Transport Processes Investigation within the glacial till at the Fernald Environmental Management Project.

This report describes a model Transport Processes Investigation (TPI) where field-scale vadose zone flow and transport processes are identified and verified through a systematic field investigation at a contaminated DOE site. The objective of the TPI is to help with formulating accurate conceptual models and aid in implementing rational and cost effective site specific characterization strategies at contaminated sites with diverse hydrogeologic settings. Central to the TPI are Transport Processes Characterization (TPC) tests that incorporate field surveys and large-scale infiltration experiments. Hypotheses are formulated based on observed pedogenic and hydrogeologic features as well as information provided by literature searches. The field and literature information is then used to optimize the design of one or more infiltration experiments to field test the hypothesis. Findings from the field surveys and infiltration experiments are then synthesized to formulate accurate flow and transport conceptual models. Here we document a TPI implemented in the glacial till vadose zone at the Fernald Environmental Management Project (FEMP) in Fernald, Ohio, a US Department of Energy (DOE) uranium processing site. As a result of this TPI, the flow and transport mechanisms were identified through visualization of dye stain within extensive macro pore and fracture networks which provided the …
Date: August 1, 2007
Creator: Schwing, J. (FERMCO Technology Development, Cincinnati, OH); Roepke, Craig Senninger; Brainard, James Robert; Glass, Robert John, Jr.; Mann, Michael J. A.; Holt, Robert M. et al.
Object Type: Report
System: The UNT Digital Library
Supporting Multiple Cognitive Processing Styles Using Tailored Support Systems (open access)

Supporting Multiple Cognitive Processing Styles Using Tailored Support Systems

According to theories of cognitive processing style or cognitive control mode, human performance is more effective when an individual’s cognitive state (e.g., intuition/scramble vs. deliberate/strategic) matches his/her ecological constraints or context (e.g., utilize intuition to strive for a "good-enough" response instead of deliberating for the "best" response under high time pressure). Ill-mapping between cognitive state and ecological constraints are believed to lead to degraded task performance. Consequently, incorporating support systems which are designed to specifically address multiple cognitive and functional states e.g., high workload, stress, boredom, and initiate appropriate mitigation strategies (e.g., reduce information load) is essential to reduce plant risk. Utilizing the concept of Cognitive Control Models, this paper will discuss the importance of tailoring support systems to match an operator's cognitive state, and will further discuss the importance of these ecological constraints in selecting and implementing mitigation strategies for safe and effective system performance. An example from the nuclear power plant industry illustrating how a support system might be tailored to support different cognitive states is included.
Date: August 1, 2007
Creator: Tran, Tuan Q.; Feigh, Karen M. & Pritchett, Amy R.
Object Type: Article
System: The UNT Digital Library
Kinetics of the water adsorption driven structural transformationof ZnS nanoparticles (open access)

Kinetics of the water adsorption driven structural transformationof ZnS nanoparticles

Nanoparticles of certain materials can respond structurally to changes in their surface environments. We have previously shown that methanol, water adsorption, and aggregation-disaggregation can change the structure of 3 nm diameter zinc sulfide (ZnS). However, in prior observations of water-driven structure change, aggregation may also have taken place. Therefore, we investigated the structural consequences of water adsorption alone on anhydrous nanoparticles that were dried to minimize changes in aggregation. Using simultaneously collected small- and wide-angle x-ray scattering (SAXS/WAXS) data, we show that water vapor adsorption alone drives a structural transformation in ZnS nanoparticles in the temperature range 22-40 C. The transition kinetics are strongly temperature dependent, with an activation energy of 58.1 {+-} 9.8 kJ/mol, consistent with atom displacement rather than bond breaking. At 50 C, aggregate restructuring occurred, increasing the transition kinetics beyond the rate expected for water adsorption alone. The observation of isosbestic points in the WAXS data suggests that the particles do not transform continuously between the initial and final structural state but rather undergo an abrupt change from a less ordered to a more ordered state.
Date: August 1, 2007
Creator: Goodell, C. M.; Gilbert, B.; Weigand, S. J. & Banfield, J. F.
Object Type: Article
System: The UNT Digital Library
IMG/M: A data management and analysis system for metagenomes (open access)

IMG/M: A data management and analysis system for metagenomes

IMG/M is a data management and analysis system for microbial community genomes (metagenomes) hosted at the Joint Genome Institute (JGI). IMG/M consists of metagenome data integrated with isolate microbial genomes from the Integrated Microbial Genomes (IMG) system. IMG/M provides IMG's comparative data analysis tools extended to handle metagenome data, together with metagenome-specific analysis tools. IMG/M is available at http://img.jgi.doe.gov/m. Studies of the collective genomes (also known as metagenomes) of environmental microbial communities (also known as microbiomes) are expected to lead to advances in environmental cleanup, agriculture, industrial processes, alternative energy production, and human health (1). Metagenomes of specific microbiome samples are sequenced by organizations worldwide, such as the Department of Energy's (DOE) Joint Genome Institute (JGI), the Venter Institute and the Washington University in St. Louis using different sequencing strategies, technology platforms, and annotation procedures. According to the Genomes OnLine Database, about 28 metagenome studies have been published to date, with over 60 other projects ongoing and more in the process of being launched (2). The Department of Energy's (DOE) Joint Genome Institute (JGI) is one of the major contributors of metagenome sequence data, currently sequencing more than 50% of the reported metagenome projects worldwide. Due to the higher complexity, …
Date: August 1, 2007
Creator: Markowitz, Victor M.; Ivanova, Natalia N.; Szeto, Ernest; Palaniappan, Krishna; Chu, Ken; Dalevi, Daniel et al.
Object Type: Article
System: The UNT Digital Library
Neutral Beam Injection for Plasma and Magnetic FieldDiagnostics (open access)

Neutral Beam Injection for Plasma and Magnetic FieldDiagnostics

At the Lawrence Berkeley National Laboratory (LBNL) adiagnostic neutral beam injection system for measuring plasma parameters,flow velocity, and local magnetic field is being developed. High protonfraction and small divergence is essential for diagnostic neutral beams.In our design, a neutral hydrogen beam with an 8 cm x 11 cm (or smaller)elliptical beam spot at 2.5 m from the end of the extraction column isproduced. The beam will deliver up to 5 A of hydrogen beam to the targetwith a pulse width of ~;1 s, once every 1 - 2 min. The H1+ ion species ofthe hydrogen beamwill be over 90 percent. For this application, we havecompared two types of RF driven multicusp ion sources operating at 13.56MHz. The first one is an ion source with an external spiral antennabehind a dielectric RF-window. The second one uses an internal antenna insimilar ion source geometry. The source needs to generate uniform plasmaover a large (8 cm x 5 cm) extraction area. We expect that the ion sourcewith internal antenna will be more efficient at producing the desiredplasma density but might have the issue of limited antenna lifetime,depending on the duty factor. For both approaches there is a need forextra shielding to protect the …
Date: August 1, 2007
Creator: Vainionpaa, Jaakko Hannes; Leung, Ka Ngo; Kwan, Joe W. & Levinton,Fred
Object Type: Article
System: The UNT Digital Library
Neutrino oscillation results from MINOS (open access)

Neutrino oscillation results from MINOS

The Main Injector Neutrino Oscillation Search (MINOS) long-baseline experiment has been actively collecting beam data since 2005, having already accumulated 3 x 10{sup 20} protons-on-target (POT). MINOS uses the Neutrinos at the Main Injector (NuMI) neutrino beam measured in two locations: at Fermilab, close to beam production, and 735 km downstream, in Northern Minnesota. By observing the oscillatory structure in the neutrino energy spectrum, MINOS can precisely measure the neutrino oscillation parameters in the atmospheric sector. These parameters were determined to be |{Delta}m{sub 32}{sup 2}| = 2.74{sub -0.26}{sup +0.44} x 10{sup -3} eV{sup 2}/c{sup 4} and sin{sup 2}(2{theta}{sub 23}) > 0.87 (68% C.L.) from analysis of the first year of data, corresponding to 1.27 x 10{sup 20} POT.
Date: August 1, 2007
Creator: Sousa, Alexandre
Object Type: Article
System: The UNT Digital Library
Energy in the Mountain West: Colonialism and Independence (open access)

Energy in the Mountain West: Colonialism and Independence

In many ways, the mountain west (Alaska, Arizona, Colorado, Idaho, Montana, New Mexico, Nevada, Utah, Wyoming) is an energy colony for the rest of the United States: it is rich in energy resources that are extracted to fuel economic growth in the wealthier and more populous coastal regions. Federal agencies and global corporations often behave as if the mountain west is a place to be exploited or managed for the benefit of customers and consumers elsewhere. Yet, the area. is not vast empty space with a limitless supply of natural resources, but rather a fast-growing region with a diverse economic base dependent on a limited supply of water. New decision processes and collaborations are slowly changing this situation, but in a piecemeal fashion that places local communities at odds with powerful external interests. Proper planning of major development is needed to insure that the west has a strong economic and cultural future after the fossil energy resources decline, even if that might be a century from now. To encourage the necessary public discussions, this paper identifies key differences between the mountain west and the rest of the United States and suggests some holistic approaches that could improve our future. This …
Date: August 1, 2007
Creator: Piet, Steven; Brown, Lloyd; Cherry, Robert; Cooper, Craig; Heydt, Harold; Holman, Richard et al.
Object Type: Article
System: The UNT Digital Library
Advantages and Disadvantages of Physiological Assessment For Next Generation Control Room Design (open access)

Advantages and Disadvantages of Physiological Assessment For Next Generation Control Room Design

Abstract - We propose using non-obtrusive physiological assessment (e.g., eye tracking,) to assess human information processing errors (e.g., loss of vigilance) and limitations (e.g., workload) for advanced energy systems early in the design process. This physiological approach for assessing risk will circumvent many limitations of current risk methodologies such as subjective rating (e.g., rater’s biases) and performance modeling (e.g., risk assessment is scripted and is based upon the individual modeler’s judgment). Key uses will be to evaluate (early in the design process) novel control room equipment and configurations as well as newly developed automated systems that will inevitably place a high information load on operators. The physiological risk assessment tool will allow better precision in pinpointing problematic design issues and will provide a “real-time” assessment of risk. Furthermore, this physiological approach would extend the state-of-the-art of human reliability methods from a “static” measure to more “dynamic.” This paper will discuss a broad range of the current popular online performance gauges as well as its advantages and disadvantages for use in next generation control room.
Date: August 1, 2007
Creator: Tran, Tuan Q.; Boring, Ronald L.; Dudenhoeffer, Donald D.; Hallbert, Bruce P; Keller, M. David & Anderson, Tessa M.
Object Type: Article
System: The UNT Digital Library
Final report : PATTON Alliance gazetteer evaluation project. (open access)

Final report : PATTON Alliance gazetteer evaluation project.

In 2005 the National Ground Intelligence Center (NGIC) proposed that the PATTON Alliance provide assistance in evaluating and obtaining the Integrated Gazetteer Database (IGDB), developed for the Naval Space Warfare Command Research group (SPAWAR) under Advance Research and Development Activity (ARDA) funds by MITRE Inc., fielded to the text-based search tool GeoLocator, currently in use by NGIC. We met with the developers of GeoLocator and identified their requirements for a better gazetteer. We then validated those requirements by reviewing the technical literature, meeting with other members of the intelligence community (IC), and talking with both the United States Geologic Survey (USGS) and the National Geospatial Intelligence Agency (NGA), the authoritative sources for official geographic name information. We thus identified 12 high-level requirements from users and the broader intelligence community. The IGDB satisfies many of these requirements. We identified gaps and proposed ways of closing these gaps. Three important needs have not been addressed but are critical future needs for the broader intelligence community. These needs include standardization of gazetteer data, a web feature service for gazetteer information that is maintained by NGA and USGS but accessible to users, and a common forum that brings together IC stakeholders and federal agency …
Date: August 1, 2007
Creator: Bleakly, Denise Rae
Object Type: Report
System: The UNT Digital Library
Searches for squarks and gluinos at CDF and D0 detectors (open access)

Searches for squarks and gluinos at CDF and D0 detectors

This contribution reports on preliminary measurements of searches for squarks and gluinos at CDF and D0 detectors in p{bar p} collisions at {radical}s = 1.96 TeV using 1 fb{sup -1} of data. The analyses are optimized for event topologies with multiple jets and large missing transverse energy in the final state. No excess with respect to the Standard Model predictions is observed and new limits on the gluino and squark masses are extracted in a mSUGRA scenario with R-parity conservation.
Date: August 1, 2007
Creator: Portell, Xavier
Object Type: Article
System: The UNT Digital Library
Quantitative X-ray microanalysis of submicron carbide formation in chromium (III) oxide rich scale (open access)

Quantitative X-ray microanalysis of submicron carbide formation in chromium (III) oxide rich scale

This paper discusses the chemical microanalysis techniques adapted to identify the precipitates that form on the surface of, or within, the oxide scale of a Fe-22Cr ferritic steel during exposure to a carbon-monoxide rich environment at 750C for 800 hours. Examination of oxidized test coupons revealed the presence of a fiber like structure at the surface, shown in figure 1. Other studies have reported that these structures are carbon precipitates.
Date: August 1, 2007
Creator: Collins, W.K.; Ziomek-Moroz, M.; Holcomb, G.R.; Danielson, P. & Hunt, A.H
Object Type: Article
System: The UNT Digital Library
Safety and Nonsafety Communications and Interactions in International Nuclear Power Plants (open access)

Safety and Nonsafety Communications and Interactions in International Nuclear Power Plants

Current industry and NRC guidance documents such as IEEE 7-4.3.2, Reg. Guide 1.152, and IEEE 603 do not sufficiently define a level of detail for evaluating interdivisional communications independence. The NRC seeks to establish criteria for safety systems communications that can be uniformly applied in evaluation of a variety of safety system designs. This report focuses strictly on communication issues related to data sent between safety systems and between safety and nonsafety systems. Further, the report does not provide design guidance for communication systems nor present detailed failure modes and effects analysis (FMEA) results for existing designs. This letter report describes communications between safety and nonsafety systems in nuclear power plants outside the United States. A limited study of international nuclear power plants was conducted to ascertain important communication implementations that might have bearing on systems proposed for licensing in the United States. This report provides that following information: 1.communications types and structures used in a representative set of international nuclear power reactors, and 2.communications issues derived from standards and other source documents relevant to safety and nonsafety communications. Topics that are discussed include the following: communication among redundant safety divisions, communications between safety divisions and nonsafety systems, control of …
Date: August 1, 2007
Creator: Kisner, Roger A; Mullens, James Allen; Wilson, Thomas L; Wood, Richard Thomas; Korsah, Kofi; Qualls, A L et al.
Object Type: Report
System: The UNT Digital Library
Technical Issues Associated With the Use of Intermediate Ethanol Blends (>E10) in the U.S. Legacy Fleet (open access)

Technical Issues Associated With the Use of Intermediate Ethanol Blends (>E10) in the U.S. Legacy Fleet

The Oak Ridge National Laboratory (ORNL) supports the U.S. Department of Energy (DOE) in assessing the impact of using intermediate ethanol blends (E10 to E30) in the legacy fleet of vehicles in the U.S. fleet. The purpose of this report is to: (1) identify the issues associated with intermediate ethanol blends with an emphasis on the end-use or vehicle impacts of increased ethanol levels; (2) assess the likely severity of the issues and whether they will become more severe with higher ethanol blend levels, or identify where the issue is most severe; (3) identify where gaps in knowledge exist and what might be required to fill those knowledge gaps; and (4) compile a current and complete bibliography of key references on intermediate ethanol blends. This effort is chiefly a critical review and assessment of available studies. Subject matter experts (authors and selected expert contacts) were consulted to help with interpretation and assessment. The scope of this report is limited to technical issues. Additional issues associated with consumer, vehicle manufacturer, and regulatory acceptance of ethanol blends greater than E10 are not considered. The key findings from this study are given.
Date: August 1, 2007
Creator: Rich, Bechtold; Thomas, John F; Huff, Shean P; Szybist, James P; West, Brian H; Theiss, Timothy J et al.
Object Type: Report
System: The UNT Digital Library
Anatomy of a SAR impulse response. (open access)

Anatomy of a SAR impulse response.

A principal measure of Synthetic Aperture Radar (SAR) image quality is the manifestation in the SAR image of a spatial impulse, that is, the SAR's Impulse Response (IPR). IPR requirements direct certain design decisions in a SAR. Anomalies in the IPR can point to specific anomalous behavior in the radar's hardware and/or software.
Date: August 1, 2007
Creator: Doerry, Armin Walter
Object Type: Report
System: The UNT Digital Library
Impact of the U.S. National Building Information Model Standard (NBIMS) on Building Energy Performance Simulation (open access)

Impact of the U.S. National Building Information Model Standard (NBIMS) on Building Energy Performance Simulation

The U.S. National Institute for Building Sciences (NIBS) started the development of the National Building Information Model Standard (NBIMS). Its goal is to define standard sets of data required to describe any given building in necessary detail so that any given AECO industry discipline application can find needed data at any point in the building lifecycle. This will include all data that are used in or are pertinent to building energy performance simulation and analysis. This paper describes the background that lead to the development of NBIMS, its goals and development methodology, its Part 1 (Version 1.0), and its probable impact on building energy performance simulation and analysis.
Date: August 1, 2007
Creator: Bazjanac, Vladimir
Object Type: Article
System: The UNT Digital Library
The integrated microbial genomes (IMG) system in 2007: datacontent and analysis tool extensions (open access)

The integrated microbial genomes (IMG) system in 2007: datacontent and analysis tool extensions

The Integrated Microbial Genomes (IMG) system is a data management, analysis and annotation platform for all publicly available genomes. IMG contains both draft and complete JGI microbial genomes integrated with all other publicly available genomes from all three domains of life, together with a large number of plasmids and viruses. IMG provides tools and viewers for analyzing and annotating genomes, genes and functions, individually or in a comparative context. Since its first release in 2005, IMG's data content and analytical capabilities have been constantly expanded through quarterly releases. IMG is provided by the DOE-Joint Genome Institute (JGI) and is available from http://img.jgi.doe.gov.
Date: August 1, 2007
Creator: Markowitz, Victor M.; Szeto, Ernest; Palaniappan, Krishna; Grechkin, Yuri; Chu, Ken; Chen, I-Min A. et al.
Object Type: Article
System: The UNT Digital Library
The Absolute, Relative and Multi-Wavelength Calibration of the Pierre Auger Observatory Fluorescence Detectors (open access)

The Absolute, Relative and Multi-Wavelength Calibration of the Pierre Auger Observatory Fluorescence Detectors

Absolute calibration of the Pierre Auger Observatory fluorescence detectors uses a 375 nm light source at the telescope aperture. This end-to-end technique accounts for the combined effects of all detector components in a single measurement. The relative response has been measured at wavelengths of 320, 337, 355, 380 and 405 nm, defining a spectral response curve which has been normalized to the absolute calibration. Before and after each night of data taking a relative calibration of the phototubes is performed. This relative calibration is used to track both short and long term changes in the detector's response. A cross check of the calibration in some phototubes is performed using an independent laser technique. Overall uncertainties, current results and future plans are discussed.
Date: August 1, 2007
Creator: Knapik, R.; Bauleo, P.; Becker, B.R.; Brack, J.; Caruso, R.; Fratte, C.Delle et al.
Object Type: Article
System: The UNT Digital Library
Results of LLNL investigation of NYCT data sets (open access)

Results of LLNL investigation of NYCT data sets

Upon examination we have concluded that none of the alarms indicate the presence of a real threat. A brief history and results from our examination of the NYCT ASP occupancy data sets dated from 2007-05-14 19:11:07 to 2007-06-20 15:46:15 are presented in this letter report. When the ASP data collection campaign at NYCT was completed, rather than being shut down, the Canberra ASP annunciator box was unplugged leaving the data acquisition system running. By the time it was discovered that the ASP was still acquiring data about 15,000 occupancies had been recorded. Among these were about 500 alarms (classified by the ASP analysis system as either Threat Alarms or Suspect Alarms). At your request, these alarms have been investigated. Our conclusion is that none of the alarm data sets indicate the presence of a real threat (within statistics). The data sets (ICD1 and ICD2 files with concurrent JPEG pictures) were delivered to LLNL on a removable hard drive labeled FOUO. The contents of the data disk amounted to 53.39 GB of data requiring over two days for the standard LLNL virus checking software to scan before work could really get started. Our first step was to walk through the directory …
Date: August 1, 2007
Creator: Sale, K.; Harrison, M.; Guo, M. & Groza, M.
Object Type: Report
System: The UNT Digital Library
High-Resolution Structure of the Photosynthetic Mn4Ca Catalyst from X-ray Spectroscopy (open access)

High-Resolution Structure of the Photosynthetic Mn4Ca Catalyst from X-ray Spectroscopy

The application of high-resolution X-ray spectroscopy methods to study the photosynthetic water oxidizing complex, which contains a unique hetero-nuclear catalytic Mn4Ca cluster, are described. Issues of X-ray damage especially at the metal sites in the Mn4Ca cluster are discussed. The structure of the Mn4Ca catalyst at high-resolution which has so far eluded attempts of determination by X-ray diffraction, EXAFS and other spectroscopic techniques has been addressed using polarized EXAFS techniques applied to oriented PS II membrane preparations and PS II single crystals. A review of how the resolution of traditional EXAFS techniques can be improved, using methods such as range-extended EXAFS is presented, and the changes that occur in the structure of the cluster as it advances through the catalytic cycle are described. X-ray absorption and emission techniques (XANES and K? emission) have been used earlier to determine the oxidation states of the Mn4Ca cluster, and in this report we review the use of X-ray resonant Raman spectroscopy to understand the electronic structure of the Mn4Ca cluster as it cycles through the intermediate S-states.
Date: August 1, 2007
Creator: Yachandra, Vittal; Yano, Junko; Kern, Jan; Pushkar, Yulia; Sauer, Kenneth; Glatzel, Pieter et al.
Object Type: Article
System: The UNT Digital Library
Topological Landscapes: A Terrain Metaphor for ScientificData (open access)

Topological Landscapes: A Terrain Metaphor for ScientificData

Scientific visualization and illustration tools are designed to help people understand the structure and complexity of scientific data with images that are as informative and intuitive as possible. In this context, the use of metaphors plays an important role, since they make complex information easily accessible by using commonly known concepts. In this paper we propose a new metaphor, called 'Topological Landscapes', which facilitates understanding the topological structure of scalar functions. The basic idea is to construct a terrain with the same topology as a given dataset and to display the terrain as an easily understood representation of the actual input data. In this projection from an n-dimensional scalar function to a two-dimensional (2D) model we preserve function values of critical points, the persistence (function span) of topological features, and one possible additional metric property (in our examples volume). By displaying this topologically equivalent landscape together with the original data we harness the natural human proficiency in understanding terrain topography and make complex topological information easily accessible.
Date: August 1, 2007
Creator: Weber, Gunther H.; Bremer, Peer-Timo & Pascucci, Valerio
Object Type: Article
System: The UNT Digital Library
Lessons Learned from Dependency Usage in HERA: Implications for THERP-Related HRA Methods (open access)

Lessons Learned from Dependency Usage in HERA: Implications for THERP-Related HRA Methods

Dependency occurs when the probability of success or failure on one action changes the probability of success or failure on a subsequent action. Dependency may serve as a modifier on the human error probabilities (HEPs) for successive actions in human reliability analysis (HRA) models. Discretion should be employed when determining whether or not a dependency calculation is warranted: dependency should not be assigned without strongly grounded reasons. Human reliability analysts may sometimes assign dependency in cases where it is unwarranted. This inappropriate assignment is attributed to a lack of clear guidance to encompass the range of scenarios human reliability analysts are addressing. Inappropriate assignment of dependency produces inappropriately elevated HEP values. Lessons learned about dependency usage in the Human Event Repository and Analysis (HERA) system may provide clarification and guidance for analysts using first-generation HRA methods. This paper presents the HERA approach to dependency assessment and discusses considerations for dependency usage in HRA, including the cognitive basis for dependency, direction for determining when dependency should be assessed, considerations for determining the dependency level, temporal issues to consider when assessing dependency, (e.g., considering task sequence versus overall event sequence, and dependency over long periods of time), and diagnosis and action influences …
Date: August 1, 2007
Creator: Whaley, April M.; Boring, Ronald L.; Blackman, Harold S.; McCabe, Patrick H. & Hallbert, Bruce P.
Object Type: Article
System: The UNT Digital Library