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Sample records for generation item reduction

  1. Development of a questionnaire to assess patient satisfaction with allergen-specific immunotherapy in adults: item generation, item reduction, and preliminary validation

    Directory of Open Access Journals (Sweden)

    Justícia JL

    2011-05-01

    Full Text Available Jose Luis Justícia1, Eva Baró2, Victoria Cardona3, Pedro Guardia4, Pedro Ojeda5, José Maria Olaguíbel6, José Maria Vega7, Carmen Vidal81Medical Department, Stallergenes Ibérica, Barcelona, Spain; 2Health Outcomes Research Department, 3D Health Research, Barcelona, Spain; 3Hospital Vall d'Hebron, Barcelona, Spain; 4Hospital Virgen Macarena, Sevilla, Spain; 5Clínica de Asma y Alergia Dres. Ojeda, Madrid, Spain; 6Complejo Hospitalario de Navarra, Pamplona, Spain; 7Hospital Regional Universitario Carlos Haya Málaga, Spain; 8Complejo Hospitalario Universitario de Santiago, Santiago de Compostela, SpainBackground: Allergen-specific immunotherapy (SIT is a treatment capable of modifying the natural course of allergy, so ensuring good adherence to SIT is fundamental. Up until now there has not existed an instrument specifically developed to measure patient satisfaction with SIT, although its assessment could help us to comprehend better and improve treatment adherence and effectiveness. The aim of this study was to develop an instrument to measure adult patient satisfaction with SIT.Methods: Items were generated from a literature review, focus groups with allergic adult patients undergoing SIT, and a meeting with experts. Potential items were administered to allergic patients undergoing SIT in an observational, cross-sectional, multicenter study. Item reduction was based on quantitative and qualitative criteria. A preliminary assessment of feasibility, reliability, and validity of the retained items was performed.Results: An initial pool of 70 items was administered to 257 patients undergoing SIT. Fifty-four items were eliminated resulting in a provisional instrument with 16 items. Factor analysis yielded four factors that were identified as perceived efficacy, activities and environment, cost-benefit balance, and overall satisfaction, explaining 74.8% of variance. Ceiling and floor effects were negligible for overall score. Overall score was

  2. Development of an assessment tool to measure students′ perceptions of respiratory care education programs: Item generation, item reduction, and preliminary validation

    Directory of Open Access Journals (Sweden)

    Ghazi Alotaibi

    2013-01-01

    Full Text Available Objectives: Students who perceived their learning environment positively are more likely to develop effective learning strategies, and adopt a deep learning approach. Currently, there is no validated instrument for measuring the educational environment of educational programs on respiratory care (RC. The aim of this study was to develop an instrument to measure students′ perception of the RC educational environment. Materials and Methods: Based on the literature review and an assessment of content validity by multiple focus groups of RC educationalists, potential items of the instrument relevant to RC educational environment construct were generated by the research group. The initial 71 item questionnaire was then field-tested on all students from the 3 RC programs in Saudi Arabia and was subjected to multi-trait scaling analysis. Cronbach′s alpha was used to assess internal consistency reliabilities. Results: Two hundred and twelve students (100% completed the survey. The initial instrument of 71 items was reduced to 65 across 5 scales. Convergent and discriminant validity assessment demonstrated that the majority of items correlated more highly with their intended scale than a competing one. Cronbach′s alpha exceeded the standard criterion of >0.70 in all scales except one. There was no floor or ceiling effect for scale or overall score. Conclusions: This instrument is the first assessment tool developed to measure the RC educational environment. There was evidence of its good feasibility, validity, and reliability. This first validation of the instrument supports its use by RC students to evaluate educational environment.

  3. The Role of Item Models in Automatic Item Generation

    Science.gov (United States)

    Gierl, Mark J.; Lai, Hollis

    2012-01-01

    Automatic item generation represents a relatively new but rapidly evolving research area where cognitive and psychometric theories are used to produce tests that include items generated using computer technology. Automatic item generation requires two steps. First, test development specialists create item models, which are comparable to templates…

  4. Approximation Preserving Reductions among Item Pricing Problems

    Science.gov (United States)

    Hamane, Ryoso; Itoh, Toshiya; Tomita, Kouhei

    When a store sells items to customers, the store wishes to determine the prices of the items to maximize its profit. Intuitively, if the store sells the items with low (resp. high) prices, the customers buy more (resp. less) items, which provides less profit to the store. So it would be hard for the store to decide the prices of items. Assume that the store has a set V of n items and there is a set E of m customers who wish to buy those items, and also assume that each item i ∈ V has the production cost di and each customer ej ∈ E has the valuation vj on the bundle ej ⊆ V of items. When the store sells an item i ∈ V at the price ri, the profit for the item i is pi = ri - di. The goal of the store is to decide the price of each item to maximize its total profit. We refer to this maximization problem as the item pricing problem. In most of the previous works, the item pricing problem was considered under the assumption that pi ≥ 0 for each i ∈ V, however, Balcan, et al. [In Proc. of WINE, LNCS 4858, 2007] introduced the notion of “loss-leader, ” and showed that the seller can get more total profit in the case that pi < 0 is allowed than in the case that pi < 0 is not allowed. In this paper, we derive approximation preserving reductions among several item pricing problems and show that all of them have algorithms with good approximation ratio.

  5. Using automatic item generation to create multiple-choice test items.

    Science.gov (United States)

    Gierl, Mark J; Lai, Hollis; Turner, Simon R

    2012-08-01

    Many tests of medical knowledge, from the undergraduate level to the level of certification and licensure, contain multiple-choice items. Although these are efficient in measuring examinees' knowledge and skills across diverse content areas, multiple-choice items are time-consuming and expensive to create. Changes in student assessment brought about by new forms of computer-based testing have created the demand for large numbers of multiple-choice items. Our current approaches to item development cannot meet this demand. We present a methodology for developing multiple-choice items based on automatic item generation (AIG) concepts and procedures. We describe a three-stage approach to AIG and we illustrate this approach by generating multiple-choice items for a medical licensure test in the content area of surgery. To generate multiple-choice items, our method requires a three-stage process. Firstly, a cognitive model is created by content specialists. Secondly, item models are developed using the content from the cognitive model. Thirdly, items are generated from the item models using computer software. Using this methodology, we generated 1248 multiple-choice items from one item model. Automatic item generation is a process that involves using models to generate items using computer technology. With our method, content specialists identify and structure the content for the test items, and computer technology systematically combines the content to generate new test items. By combining these outcomes, items can be generated automatically. © Blackwell Publishing Ltd 2012.

  6. Instructional Topics in Educational Measurement (ITEMS) Module: Using Automated Processes to Generate Test Items

    Science.gov (United States)

    Gierl, Mark J.; Lai, Hollis

    2013-01-01

    Changes to the design and development of our educational assessments are resulting in the unprecedented demand for a large and continuous supply of content-specific test items. One way to address this growing demand is with automatic item generation (AIG). AIG is the process of using item models to generate test items with the aid of computer…

  7. Automatic Item Generation via Frame Semantics: Natural Language Generation of Math Word Problems.

    Science.gov (United States)

    Deane, Paul; Sheehan, Kathleen

    This paper is an exploration of the conceptual issues that have arisen in the course of building a natural language generation (NLG) system for automatic test item generation. While natural language processing techniques are applicable to general verbal items, mathematics word problems are particularly tractable targets for natural language…

  8. Verbal fluency: Effect of time on item generation

    Directory of Open Access Journals (Sweden)

    Mayra Jacuviske Venegas

    Full Text Available Abstract The distribution of item generation/time in the performance of elderly on verbal fluency (VF remains unknown. Objective: To analyze the number of items, their distribution and impact of the first quartile on the final test result. Methods: 31 individuals performed the tests (average age=74 years; schooling=8.16 years. Results: The number of items produced in the first quartile differed from the other quartiles for both semantic and phonologic VF where 40% of items were produced in the first quartile. No effect of age was found and schooling influenced performance on the first and second quartiles of semantic VF and on the 1st, 2nd and 3rd quartiles of phonemic VF. Discussion: This study contributes with the finding that asymptotic levels are attained prior to the 30 seconds observed in other studies, being reached at the 15-second mark. Furthermore, schooling was found to be associated to the number of items produced in both the first and 2nd quartiles for semantic VF, and in 1st, 2nd and 3rd quartiles for phonemic fluency. Conclusion: The schooling effect was noted both in semantic and executive aspects of VF. The brief form of the VF test may represent a promising tool for clinical evaluation.

  9. Evaluating the Psychometric Characteristics of Generated Multiple-Choice Test Items

    Science.gov (United States)

    Gierl, Mark J.; Lai, Hollis; Pugh, Debra; Touchie, Claire; Boulais, André-Philippe; De Champlain, André

    2016-01-01

    Item development is a time- and resource-intensive process. Automatic item generation integrates cognitive modeling with computer technology to systematically generate test items. To date, however, items generated using cognitive modeling procedures have received limited use in operational testing situations. As a result, the psychometric…

  10. Evaluating the Psychometric Characteristics of Generated Multiple-Choice Test Items

    Science.gov (United States)

    Gierl, Mark J.; Lai, Hollis; Pugh, Debra; Touchie, Claire; Boulais, André-Philippe; De Champlain, André

    2016-01-01

    Item development is a time- and resource-intensive process. Automatic item generation integrates cognitive modeling with computer technology to systematically generate test items. To date, however, items generated using cognitive modeling procedures have received limited use in operational testing situations. As a result, the psychometric…

  11. A Model-Based Method for Content Validation of Automatically Generated Test Items

    Science.gov (United States)

    Zhang, Xinxin; Gierl, Mark

    2016-01-01

    The purpose of this study is to describe a methodology to recover the item model used to generate multiple-choice test items with a novel graph theory approach. Beginning with the generated test items and working backward to recover the original item model provides a model-based method for validating the content used to automatically generate test…

  12. A Process for Reviewing and Evaluating Generated Test Items

    Science.gov (United States)

    Gierl, Mark J.; Lai, Hollis

    2016-01-01

    Testing organization needs large numbers of high-quality items due to the proliferation of alternative test administration methods and modern test designs. But the current demand for items far exceeds the supply. Test items, as they are currently written, evoke a process that is both time-consuming and expensive because each item is written,…

  13. Analysis of Software Test Item Generation- Comparison Between High Skilled and Low Skilled Engineers

    Institute of Scientific and Technical Information of China (English)

    Masayuki Hirayama; Osamu Mizuno; Tohru Kikuno

    2005-01-01

    Recent software system contain many functions to provide various services. According to this tendency, it is difficult to ensure software quality and to eliminate crucial faults by conventional software testing methods. So taking the effect of test engineer's skill on test item generation into consideration, we propose a new test item generation method,which supports the generation of test items for illegal behavior of the system. The proposed method can generate test items based on use-case analysis, deviation analysis for legal behavior, and faults tree analysis for system fault situations. From the results of the experimental applications of our method, we confirmed that test items for illegal behavior of a system were effectively generated, and also the proposed method could effectively assist test item generation by an engineer with low-level skill.

  14. Explaining and Controlling for the Psychometric Properties of Computer-Generated Figural Matrix Items

    Science.gov (United States)

    Freund, Philipp Alexander; Hofer, Stefan; Holling, Heinz

    2008-01-01

    Figural matrix items are a popular task type for assessing general intelligence (Spearman's g). Items of this kind can be constructed rationally, allowing the implementation of computerized generation algorithms. In this study, the influence of different task parameters on the degree of difficulty in matrix items was investigated. A sample of N =…

  15. The Comparability of the Statistical Characteristics of Test Items Generated by Computer Algorithms.

    Science.gov (United States)

    Meisner, Richard; And Others

    This paper presents a study on the generation of mathematics test items using algorithmic methods. The history of this approach is briefly reviewed and is followed by a survey of the research to date on the statistical parallelism of algorithmically generated mathematics items. Results are presented for 8 parallel test forms generated using 16…

  16. A Method for Generating Educational Test Items That Are Aligned to the Common Core State Standards

    Science.gov (United States)

    Gierl, Mark J.; Lai, Hollis; Hogan, James B.; Matovinovic, Donna

    2015-01-01

    The demand for test items far outstrips the current supply. This increased demand can be attributed, in part, to the transition to computerized testing, but, it is also linked to dramatic changes in how 21st century educational assessments are designed and administered. One way to address this growing demand is with automatic item generation.…

  17. Using Automated Processes to Generate Test Items And Their Associated Solutions and Rationales to Support Formative Feedback

    Directory of Open Access Journals (Sweden)

    Mark Gierl

    2015-08-01

    Full Text Available Automatic item generation is the process of using item models to produce assessment tasks using computer technology. An item model is similar to a template that highlights the elements in the task that must be manipulated to produce new items. The purpose of our study is to describe an innovative method for generating large numbers of diverse and heterogeneous items along with their solutions and associated rationales to support formative feedback. We demonstrate the method by generating items in two diverse content areas, mathematics and nonverbal reasoning

  18. A Generative Approach to the Modeling of Isomorphic Hidden-Figure Items.

    Science.gov (United States)

    Bejar, Isaac I.; Yocom, Peter

    1991-01-01

    An approach to test modeling is illustrated that encompasses both response consistency and response difficulty. This generative approach makes validation an ongoing process. An analysis of hidden figure items with 60 high school students supports the feasibility of the method. (SLD)

  19. Ordering Cost Reduction in Inventory Model with Defective Items and Backorder Price Discount

    Directory of Open Access Journals (Sweden)

    Karuppuchamy Annadurai

    2014-01-01

    Full Text Available In the real market, as unsatisfied demands occur, the longer the length of lead time is, the smaller the proportion of backorder would be. In order to make up for the inconvenience and even the losses of royal and patient customers, the supplier may offer a backorder price discount to secure orders during the shortage period. Also, ordering policies determined by conventional inventory models may be inappropriate for the situation in which an arrival lot contains some defective items. To compensate for the inconvenience of backordering and to secure orders, the supplier may offer a price discount on the stockout item. The purpose of this study is to explore a coordinated inventory model including defective arrivals by allowing the backorder price discount and ordering cost as decision variables. There are two inventory models proposed in this paper, one with normally distributed demand and another with distribution free demand. A computer code using the software Matlab 7.0 is developed to find the optimal solution and present numerical examples to illustrate the models. The results in the numerical examples indicate that the savings of the total cost are realized through ordering cost reduction and backorder price discount.

  20. Reduction of Bumblebee Noise Generated by GSM

    Directory of Open Access Journals (Sweden)

    Han Su Kyi

    2014-09-01

    Full Text Available This research work presents a method for reducing a bumblebee noise generated by a GSM system. Global smart phone penetration has been very swift and 2nd generation, 3rd generation and 4th generation communication technology are commercially used in the world. GSM technology uses a channel access method that combines frequency division multiple access (FDMA and time division multiple access (TDMA. There are four commercial frequency bands. GSM technology has a burst structure by a TDMA method. And hence, the GSM technology has a disadvantage; radiation noise is generated from an antenna propagation signal of the smart phone, and consequently, the voice quality of the smart phone is degraded. This noise is commonly known as bumblebee noise, buzz noise or TDMA noise. There have been several studies to reduce the noise since a release of GSM technology in a commercial market. Those studies mainly focused on designing infinite impulse response (IIR notch filters by the signal processing technology or on data burst transmission schemes.

  1. Item reduction of the Voice Handicap Index (VHI) based on European translations.

    NARCIS (Netherlands)

    Nawka, T.; Leeuw, de I.M.; DeBodt, M.; Guimaraes, I.; Holmberg, E.B.; Schindler, A.; Woisard, V.; Whurr, R.; Konerding, U.

    2009-01-01

    Objective: Constructing an internationally applicable short-scale of the Voice Handicap Index (VHI). Methods: Subjects were 1,052 patients with 5 different types of voice disorder groups from Belgium, France, Sweden, Germany, Italy, The Netherlands, Portugal, and the USA. Different 9- and 12-item su

  2. A Generative Approach to the Development of Hidden-Figure Items.

    Science.gov (United States)

    Bejar, Issac I.; Yocom, Peter

    This report explores an approach to item development and psychometric modeling which explicitly incorporates knowledge about the mental models used by examinees in the solution of items into a psychometric model that characterize performances on a test, as well as incorporating that knowledge into the item development process. The paper focuses on…

  3. Computer Software Configuration Item-Specific Flight Software Image Transfer Script Generator

    Science.gov (United States)

    Bolen, Kenny; Greenlaw, Ronald

    2010-01-01

    A K-shell UNIX script enables the International Space Station (ISS) Flight Control Team (FCT) operators in NASA s Mission Control Center (MCC) in Houston to transfer an entire or partial computer software configuration item (CSCI) from a flight software compact disk (CD) to the onboard Portable Computer System (PCS). The tool is designed to read the content stored on a flight software CD and generate individual CSCI transfer scripts that are capable of transferring the flight software content in a given subdirectory on the CD to the scratch directory on the PCS. The flight control team can then transfer the flight software from the PCS scratch directory to the Electronically Erasable Programmable Read Only Memory (EEPROM) of an ISS Multiplexer/ Demultiplexer (MDM) via the Indirect File Transfer capability. The individual CSCI scripts and the CSCI Specific Flight Software Image Transfer Script Generator (CFITSG), when executed a second time, will remove all components from their original execution. The tool will identify errors in the transfer process and create logs of the transferred software for the purposes of configuration management.

  4. Generating an item pool for translational social cognition research: methodology and initial validation.

    Science.gov (United States)

    Keutmann, Michael K; Moore, Samantha L; Savitt, Adam; Gur, Ruben C

    2015-03-01

    Existing sets of social and emotional stimuli suitable for social cognition research are limited in many ways, including size, unimodal stimulus delivery, and restriction to major universal emotions. Existing measures of social cognition could be improved by taking advantage of item response theory and adaptive testing technology to develop instruments that obtain more efficient measures of multimodal social cognition. However, for this to be possible, large pools of emotional stimuli must be obtained and validated. We present the development of a large, high-quality multimedia stimulus set produced by professional adult and child actors (ages 5 to 74) containing both visual and vocal emotional expressions. We obtained over 74,000 audiovisual recordings of a wide array of emotional and social behaviors, including the main universal emotions (happiness, sadness, anger, fear, disgust, and surprise), as well as more complex social expressions (pride, affection, sarcasm, jealousy, and shame). The actors generated a high quantity of technically superior, ecologically valid stimuli that were digitized, archived, and rated for accuracy and intensity of expressions. A subset of these facial and vocal expressions of emotion and social behavior were submitted for quantitative ratings to generate parameters for validity and discriminability. These stimuli are suitable for affective neuroscience-based psychometric tests, functional neuroimaging, and social cognitive rehabilitation programs. The purposes of this report are to describe the method of obtaining and validating this database and to make it accessible to the scientific community. We invite all those interested in participating in the use and validation of these stimuli to access them at www.med.upenn.edu/bbl/actors/index.shtml .

  5. TIIREC: A Tensor Approach for Tag-Driven Item Recommendation with Sparse User Generated Content

    KAUST Repository

    Yu, Lu

    2017-05-17

    In recent years, tagging system has become a building block o summarize the content of items for further functions like retrieval or personalized recommendation in various web applications. One nontrivial requirement is to precisely deliver a list of suitable items when users interact with the systems via inputing a specific tag (i.e. a query term). Different from traditional recommender systems, we need deal with a collaborative retrieval (CR) problem, where both characteristics of retrieval and recommendation should be considered to model a ternary relationship involved with query× user× item. Recently, several works are proposed to study CR task from users’ perspective. However, they miss a significant challenge raising from the sparse content of items. In this work, we argue that items will suffer from the sparsity problem more severely than users, since items are usually observed with fewer features to support a feature-based or content-based algorithm. To tackle this problem, we aim to sufficiently explore the sophisticated relationship of each query× user× item triple from items’ perspective. By integrating item-based collaborative information for this joint task, we present an alternative factorized model that could better evaluate the ranks of those items with sparse information for the given query-user pair. In addition, we suggest to employ a recently proposed bayesian personalized ranking (BPR) algorithm to optimize latent collaborative retrieval problem from pairwise learning perspective. The experimental results on two real-world datasets, (i.e. Last.fm, Yelp), verified the efficiency and effectiveness of our proposed approach at top-k ranking metric.

  6. Using Likert-type and ipsative/forced choice items in sequence to generate a preference.

    Science.gov (United States)

    Ried, L Douglas

    2014-01-01

    Collaboration and implementation of a minimum, standardized set of core global educational and professional competencies seems appropriate given the expanding international evolution of pharmacy practice. However, winnowing down hundreds of competencies from a plethora of local, national and international competency frameworks to select the most highly preferred to be included in the core set is a daunting task. The objective of this paper is to describe a combination of strategies used to ascertain the most highly preferred items among a large number of disparate items. In this case, the items were >100 educational and professional competencies that might be incorporated as the core components of new and existing competency frameworks. Panelists (n = 30) from the European Union (EU) and United States (USA) were chosen to reflect a variety of practice settings. Each panelist completed two electronic surveys. The first survey presented competencies in a Likert-type format and the second survey presented many of the same competencies in an ipsative/forced choice format. Item mean scores were calculated for each competency, the competencies were ranked, and non-parametric statistical tests were used to ascertain the consistency in the rankings achieved by the two strategies. This exploratory study presented over 100 competencies to the panelists in the beginning. The two methods provided similar results, as indicated by the significant correlation between the rankings (Spearman's rho = 0.30, P Likert-type and ipsative/forced choice formats in sequence, appears to be useful in a situation where a clear preference is required from among a large number of choices. The ipsative/forced choice format resulted in some differences in the competency preferences because the panelists could not rate them equally by design. While this strategy was used for the selection of professional educational competencies in this exploratory study, it is applicable in other situations where

  7. Thermal lift generation and drag reduction in rarefied aerodynamics

    Science.gov (United States)

    Pekardan, Cem; Alexeenko, Alina

    2016-11-01

    With the advent of the new technologies in low pressure environments such as Hyperloop and helicopters designed for Martian applications, understanding the aerodynamic behavior of airfoils in rarefied environments are becoming more crucial. In this paper, verification of rarefied ES-BGK solver and ideas such as prediction of the thermally induced lift and drag reduction in rarefied aerodynamics are investigated. Validation of the rarefied ES-BGK solver with Runge-Kutta discontinous Galerkin method with experiments in transonic regime with a Reynolds number of 73 showed that ES-BGK solver is the most suitable solver in near slip transonic regime. For the quantification of lift generation, A NACA 0012 airfoil is studied with a high temperature surface on the bottom for the lift creation for different Knudsen numbers. It was seen that for lower velocities, continuum solver under predicts the lift generation when the Knudsen number is 0.00129 due to local velocity gradients reaching slip regime although lift coefficient is higher with the Boltzmann ES-BGK solutions. In the second part, the feasibility of using thermal transpiration for drag reduction is studied. Initial study in drag reduction includes an application of a thermal gradient at the upper surface of a NACA 0012 airfoil near trailing edge at a 12-degree angle of attack and 5 Pa pressure. It was seen that drag is reduced by 4 percent and vortex shedding frequency is reduced due to asymmetry introduced in the flow due to temperature gradient causing reverse flow due to thermal transpiration phenomena.

  8. Electricity generation: options for reduction in carbon emissions.

    Science.gov (United States)

    Whittington, H W

    2002-08-15

    Historically, the bulk production of electricity has been achieved by burning fossil fuels, with unavoidable gaseous emissions, including large quantities of carbon dioxide: an average-sized modern coal-burning power station is responsible for more than 10 Mt of CO(2) each year. This paper details typical emissions from present-day power stations and discusses the options for their reduction. Acknowledging that the cuts achieved in the past decade in the UK CO(2) emissions have been achieved largely by fuel switching, the remaining possibilities offered by this method are discussed. Switching to less-polluting fossil fuels will achieve some measure of reduction, but the basic problem of CO(2) emissions continues. Of the alternatives to fossil fuels, only nuclear power represents a zero-carbon large-scale energy source. Unfortunately, public concerns over safety and radioactive waste have still to be assuaged. Other approaches include the application of improved combustion technology, the removal of harmful gases from power-station flues and the use of waste heat to improve overall power-station efficiency. These all have a part to play, but many consider our best hope for emissions reduction to be the use of renewable energy. The main renewable energy contenders are assessed in this paper and realistic estimates of the contribution that each could provide are indicated. It appears that, in the time-scale envisaged by planners for reduction in CO(2) emission, in many countries renewable energy will be unlikely to deliver. At the same time, it is worth commenting that, again in many countries, the level of penetration of renewable energy will fall short of the present somewhat optimistic targets. Of renewable options, wind energy could be used in the short to medium term to cover for thermal plant closures, but for wind energy to be successful, the network will have to be modified to cope with wind's intermittent nature. Globally, hydroelectricity is currently the

  9. The Piper Fatigue Scale-12 (PFS-12): psychometric findings and item reduction in a cohort of breast cancer survivors.

    Science.gov (United States)

    Reeve, Bryce B; Stover, Angela M; Alfano, Catherine M; Smith, Ashley Wilder; Ballard-Barbash, Rachel; Bernstein, Leslie; McTiernan, Anne; Baumgartner, Kathy B; Piper, Barbara F

    2012-11-01

    Brief, valid measures of fatigue, a prevalent and distressing cancer symptom, are needed for use in research. This study's primary aim was to create a shortened version of the revised Piper Fatigue Scale (PFS-R) based on data from a diverse cohort of breast cancer survivors. A secondary aim was to determine whether the PFS captured multiple distinct aspects of fatigue (a multidimensional model) or a single overall fatigue factor (a unidimensional model). Breast cancer survivors (n = 799; stages in situ through IIIa; ages 29-86 years) were recruited through three SEER registries (New Mexico, Western Washington, and Los Angeles, CA) as part of the Health, Eating, Activity, and Lifestyle (HEAL) study. Fatigue was measured approximately 3 years post-diagnosis using the 22-item PFS-R that has four subscales (Behavior, Affect, Sensory, and Cognition). Confirmatory factor analysis was used to compare unidimensional and multidimensional models. Six criteria were used to make item selections to shorten the PFS-R: scale's content validity, items' relationship with fatigue, content redundancy, differential item functioning by race and/or education, scale reliability, and literacy demand. Factor analyses supported the original 4-factor structure. There was also evidence from the bi-factor model for a dominant underlying fatigue factor. Six items tested positive for differential item functioning between African-American and Caucasian survivors. Four additional items either showed poor association, local dependence, or content validity concerns. After removing these 10 items, the reliability of the PFS-12 subscales ranged from 0.87 to 0.89, compared to 0.90-0.94 prior to item removal. The newly developed PFS-12 can be used to assess fatigue in African-American and Caucasian breast cancer survivors and reduces response burden without compromising reliability or validity. This is the first study to determine PFS literacy demand and to compare PFS-R responses in African

  10. Energy Reductions Using Next-Generation Remanufacturing Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Sordelet, Daniel; Racek, Ondrej

    2012-02-24

    The goal of this project was to develop a radically new surface coating approach that greatly enhances the performance of thermal spray coatings. Rather than relying on a roughened grit blasted substrate surface for developing a mechanical bond between the coating and substrate, which is the normal practice with conventional thermal spraying, a hybrid approach of combining a focused laser beam to thermally treat the substrate surface in the vicinity of the rapidly approaching thermally-sprayed powder particles was developed. This new surface coating process is targeted primarily at enabling remanufacturing of components used in engines, drive trains and undercarriage systems; thereby providing a substantial global opportunity for increasing the magnitude and breadth of parts that are remanufactured through their life cycle, as opposed to simply being replaced by new components. The projected benefits of a new remanufacturing process that increases the quantity of components that are salvaged and reused compared to being fabricated from raw materials will clearly vary based on the specific industry and range of candidate components that are considered. At the outset of this project two different metal processing routes were considered, castings and forgings, and the prototypical components for each process were liners and crankshafts, respectively. The quantities of parts used in the analysis are based on our internal production of approximately 158,000 diesel engines in 2007. This leads to roughly 1,000,000 liners (assuming a mixture of 6- and 8-cylinder engines) and 158,000 crankshafts. Using energy intensity factors for casting and forgings, respectively, of 4450 and 5970 Btu-hr/lb along with the energy-induced CO2 generation factor of 0.00038 lbs CO2/Btu, energy savings of over 17 trillion BTUs and CO2 reductions of over 6.5 million lbs could potentially be realized by remanufacturing the above mentioned quantities of crankshafts and liners. This project

  11. Energy Reductions Using Next-Generation Remanufacturing Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Sordelet, Daniel; Racek, Ondrej

    2012-02-24

    The goal of this project was to develop a radically new surface coating approach that greatly enhances the performance of thermal spray coatings. Rather than relying on a roughened grit blasted substrate surface for developing a mechanical bond between the coating and substrate, which is the normal practice with conventional thermal spraying, a hybrid approach of combining a focused laser beam to thermally treat the substrate surface in the vicinity of the rapidly approaching thermally-sprayed powder particles was developed. This new surface coating process is targeted primarily at enabling remanufacturing of components used in engines, drive trains and undercarriage systems; thereby providing a substantial global opportunity for increasing the magnitude and breadth of parts that are remanufactured through their life cycle, as opposed to simply being replaced by new components. The projected benefits of a new remanufacturing process that increases the quantity of components that are salvaged and reused compared to being fabricated from raw materials will clearly vary based on the specific industry and range of candidate components that are considered. At the outset of this project two different metal processing routes were considered, castings and forgings, and the prototypical components for each process were liners and crankshafts, respectively. The quantities of parts used in the analysis are based on our internal production of approximately 158,000 diesel engines in 2007. This leads to roughly 1,000,000 liners (assuming a mixture of 6- and 8-cylinder engines) and 158,000 crankshafts. Using energy intensity factors for casting and forgings, respectively, of 4450 and 5970 Btu-hr/lb along with the energy-induced CO2 generation factor of 0.00038 lbs CO2/Btu, energy savings of over 17 trillion BTUs and CO2 reductions of over 6.5 million lbs could potentially be realized by remanufacturing the above mentioned quantities of crankshafts and liners. This project

  12. Reduction of chlorine dioxide emissions from a Mathieson generator

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, R.

    1998-03-01

    Chlorine dioxide emissions from the ClO{sub 2} Mathison generator at Crestbrook Forest Industries was studied to determine whether changes would be necessary to meet emission restrictions. The effect of water temperature, packing height and chlorine dioxide gas concentration on emissions was determined using the gas sample data and mass transfer equations for the absorption tower and scrubber. Operation of the generator was discovered to have a significant effect on final chlorine dioxide emissions. Final solutions were evaluated based on ensuring compliance as well as minimizing capital cost. The order in which the changes should be performed to ensure compliance was determined to be (1) change in permit restrictions, (2) better operation of the generator, (3) converting the scrubber to operate with water, and (4) souring the vented gas with SO{sub 2} before being scrubbed with caustic. This would reduce emissions to near zero. However, this solution would be effective only if the SO{sub 2} addition were carefully controlled to ensure that no sodium sulphite was produced. 2 refs., 8 figs.

  13. ADVANTG An Automated Variance Reduction Parameter Generator, Rev. 1

    Energy Technology Data Exchange (ETDEWEB)

    Mosher, Scott W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Johnson, Seth R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bevill, Aaron M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ibrahim, Ahmad M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Daily, Charles R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Evans, Thomas M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wagner, John C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Johnson, Jeffrey O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Grove, Robert E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-01

    The primary objective of ADVANTG is to reduce both the user effort and the computational time required to obtain accurate and precise tally estimates across a broad range of challenging transport applications. ADVANTG has been applied to simulations of real-world radiation shielding, detection, and neutron activation problems. Examples of shielding applications include material damage and dose rate analyses of the Oak Ridge National Laboratory (ORNL) Spallation Neutron Source and High Flux Isotope Reactor (Risner and Blakeman 2013) and the ITER Tokamak (Ibrahim et al. 2011). ADVANTG has been applied to a suite of radiation detection, safeguards, and special nuclear material movement detection test problems (Shaver et al. 2011). ADVANTG has also been used in the prediction of activation rates within light water reactor facilities (Pantelias and Mosher 2013). In these projects, ADVANTG was demonstrated to significantly increase the tally figure of merit (FOM) relative to an analog MCNP simulation. The ADVANTG-generated parameters were also shown to be more effective than manually generated geometry splitting parameters.

  14. 75 FR 66008 - Fossil Fuel-Generated Energy Consumption Reduction for New Federal Buildings and Major...

    Science.gov (United States)

    2010-10-27

    ... Parts 433 and 435 RIN 1904-AB96 Fossil Fuel-Generated Energy Consumption Reduction for New Federal... proposed rulemaking (NOPR) regarding the fossil fuel- generated energy consumption ] requirements for new... regarding the fossil fuel-generated energy consumption requirements for new Federal buildings and...

  15. Generating political priority for neonatal mortality reduction in Bangladesh.

    Science.gov (United States)

    Shiffman, Jeremy; Sultana, Sharmina

    2013-04-01

    The low priority that most low-income countries give to neonatal mortality, which now constitutes more than 40% of deaths to children younger than 5 years, is a stumbling block to the world achieving the child survival Millennium Development Goal. Bangladesh is an exception to this inattention. Between 2000 and 2011, newborn survival emerged from obscurity to relative prominence on the government's health policy agenda. Drawing on a public policy framework, we analyzed how this attention emerged. Critical factors included national advocacy, government commitment to the Millennium Development Goals, and donor resources. The emergence of policy attention involved interactions between global and national factors rather than either alone. The case offers guidance on generating priority for neglected health problems in low-income countries.

  16. Reduction in oxidatively generated DNA damage following smoking cessation

    Directory of Open Access Journals (Sweden)

    Freund Harold G

    2011-05-01

    Full Text Available Abstract Background Cigarette smoking is a known cause of cancer, and cancer may be in part due to effects of oxidative stress. However, whether smoking cessation reverses oxidatively induced DNA damage unclear. The current study sought to examine the extent to which three DNA lesions showed significant reductions after participants quit smoking. Methods Participants (n = 19 in this study were recruited from an ongoing 16-week smoking cessation clinical trial and provided blood samples from which leukocyte DNA was extracted and assessed for 3 DNA lesions (thymine glycol modification [d(TgpA]; formamide breakdown of pyrimidine bases [d(TgpA]; 8-oxo-7,8-dihydroguanine [d(Gh] via liquid chromatography tandem mass spectrometry (LC-MS/MS. Change in lesions over time was assessed using generalized estimating equations, controlling for gender, age, and treatment condition. Results Overall time effects for the d(TgpA (χ2(3 = 8.068, p fpA (χ2(3 = 8.477, p h (χ2(3 = 37.599, p gpA and d(PfpA lesions show relatively greater rebound at Week 16 compared to the d(Gh lesion (88% of baseline for d(TgpA, 64% of baseline for d(PfpA, vs 46% of baseline for d(Gh. Conclusions Overall, results from this analysis suggest that cigarette smoking contributes to oxidatively induced DNA damage, and that smoking cessation appears to reduce levels of specific damage markers between 30-50 percent in the short term. Future research may shed light on the broader array of oxidative damage influenced by smoking and over longer durations of abstinence, to provide further insights into mechanisms underlying carcinogenesis.

  17. Fuel Savings and Emission Reductions from Next-Generation Mobile Air Conditioning Technology in India: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Chaney, L.; Thundiyil, K.; Chidambaram, S.; Abbi, Y. P.; Anderson, S.

    2007-05-01

    This paper quantifies the mobile air-conditioning fuel consumption of the typical Indian vehicle, exploring potential fuel savings and emissions reductions these systems for the next generation of vehicles.

  18. Enhanced vanadium (V) reduction and bioelectricity generation in microbial fuel cells with biocathode

    Science.gov (United States)

    Qiu, Rui; Zhang, Baogang; Li, Jiaxin; Lv, Qing; Wang, Song; Gu, Qian

    2017-08-01

    Microbial fuel cells (MFCs) represent a promising approach for remediation of toxic vanadium (V) contaminated environment. Herein, enhanced V(V) reduction and bioelectricity generation are realized in MFCs with biocathode. Synergistically electrochemical and microbial reductions result in the nearly complete removals of V(V) within 7 d operation with initial concentration of 200 mg L-1. Maximum power density of 529 ± 12 mW m-2 is obtained. Electrochemical tests reveal that biocathode promotes electron transfers and reduces charge transfer resistance. XPS analysis confirms that V(IV) is the main reduction product, which precipitates naturally under neutral conditions. High-throughput 16S rRNA gene sequencing analysis indicates that the newly appeared Dysgonomonas is responsible for V(V) reduction and Klebsiella contributes mainly to bioelectricity generation in MFCs with biocathode. This study further improves the performance of remediating V(V) contaminated environment based on MFC technology.

  19. Fe(III) oxides accelerate microbial nitrate reduction and electricity generation by Klebsiella pneumoniae L17.

    Science.gov (United States)

    Liu, Tongxu; Li, Xiaomin; Zhang, Wei; Hu, Min; Li, Fangbai

    2014-06-01

    Klebsiella pneumoniae L17 is a fermentative bacterium that can reduce iron oxide and generate electricity under anoxic conditions, as previously reported. This study reveals that K. pneumoniae L17 is also capable of dissimilatory nitrate reduction, producing NO2(-), NH4(+), NO and N2O under anoxic conditions. The presence of Fe(III) oxides (i.e., α-FeOOH, γ-FeOOH, α-Fe2O3 and γ-Fe2O3) significantly accelerates the reduction of nitrate and generation of electricity by K. pneumoniae L17, which is similar to a previous report regarding another fermentative bacterium, Bacillus. No significant nitrate reduction was observed upon treatment with Fe(2+) or α-FeOOH+Fe(2+), but a slight facilitation of nitrate reduction and electricity generation was observed upon treatment with L17+Fe(2+). This result suggests that aqueous Fe(II) or mineral-adsorbed Fe(II) cannot reduce nitrate abiotically but that L17 can catalyze the reduction of nitrate and generation of electricity in the presence of Fe(II) (which might exist as cell surface-bound Fe(II)). To rule out the potential effect of Fe(II) produced by L17 during microbial iron reduction, treatments with the addition of TiO2 or Al2O3 instead of Fe(III) oxides also exhibited accelerated microbial nitrate reduction and electricity generation, indicating that cell-mineral sorption did account for the acceleration effect. However, the acceleration caused by Fe(III) oxides is only partially attributed to the cell surface-bound Fe(II) and cell-mineral sorption but may be driven by the iron oxide conduction band-mediated electron transfer from L17 to nitrate or an electrode, as proposed previously. The current study extends the diversity of bacteria of which nitrate reduction and electricity generation can be facilitated by the presence of iron oxides and confirms the positive role of Fe(III) oxides on microbial nitrate reduction and electricity generation by particular fermentative bacteria in anoxic environments. Copyright

  20. Emission reduction of NOx, PM, PM-carbon, and PAHs from a generator fuelled by biodieselhols.

    Science.gov (United States)

    Tsai, Jen-Hsiung; Chen, Shui-Jen; Huang, Kuo-Lin; Lin, Wen-Yinn; Lee, Wen-Jhy; Chao, How-Ran; Lin, Chih-Chung; Hsieh, Lien-Te

    2014-06-15

    This investigation examines the particulate matter (PM), particulate carbon, polycyclic aromatic hydrocarbons (PAHs), and nitrogen oxides (NOx) emitted from a generator fueled by petroleum diesel blended with waste-edible-oil-biodiesel and water-containing acetone. Experimental results show that using biodieselhols with water-containing (or pure) acetone as the fuel of generator, in comparison to using petroleum diesel, significantly reduces PM emission; roughly, this reduction increased as percentage of water-containing acetone increased. When the percentages of waste-edible-oil-biodiesel were ≤ 5 vol%, adding pure or water-containing acetone (1-3 vol%) to biodieselhols generated emission reductions of NOx, PM, particle-bound organic carbon (OC), total-PAHs, and total-BaPeq. Consequently, using water-containing acetone biodieselhols as an alternative generator fuel is feasible and helps recycle and reuse waste solvents containing water-containing acetone.

  1. Deciphering characteristics of bicyclic aromatics--mediators for reductive decolorization and bioelectricity generation.

    Science.gov (United States)

    Xu, Bin; Chen, Bor-Yann; Hsueh, Chung-Chuan; Qin, Lian-Jie; Chang, Chang-Tang

    2014-07-01

    This first-attempt study quantitatively assessed electron-mediating characteristics of bicyclic aromatics - 1-amino-2-naphthol, 4-amino-1-naphthol (i.e., decolorized intermediates of azo dyes - orange I and II) for color removal and power generation in MFCs. According to cyclic-voltammetric profiles, the presence of reduction and oxidation peak potentials clearly suggested a crucial role of these intermediates as electron-shuttling mediators. Shake-flask cultures also showed that appropriate accumulation of 1A2N, 4A1N apparently enhanced color-removal efficiencies of bacterial decolorization. This study clearly suggested that suitable supplementation of electrochemically active electron shuttle(s) to dye-bearing MFCs is a promising strategy to stimulate reductive decolorization and bioelectricity generation.

  2. Identification of intrinsic catalytic activity for electrochemical reduction of water molecules to generate hydrogen

    KAUST Repository

    Shinagawa, Tatsuya

    2015-01-01

    Insufficient hydronium ion activities at near-neutral pH and under unbuffered conditions induce diffusion-limited currents for hydrogen evolution, followed by a reaction with water molecules to generate hydrogen at elevated potentials. The observed constant current behaviors at near neutral pH reflect the intrinsic electrocatalytic reactivity of the metal electrodes for water reduction. This journal is © the Owner Societies.

  3. A sparse grid based method for generative dimensionality reduction of high-dimensional data

    Science.gov (United States)

    Bohn, Bastian; Garcke, Jochen; Griebel, Michael

    2016-03-01

    Generative dimensionality reduction methods play an important role in machine learning applications because they construct an explicit mapping from a low-dimensional space to the high-dimensional data space. We discuss a general framework to describe generative dimensionality reduction methods, where the main focus lies on a regularized principal manifold learning variant. Since most generative dimensionality reduction algorithms exploit the representer theorem for reproducing kernel Hilbert spaces, their computational costs grow at least quadratically in the number n of data. Instead, we introduce a grid-based discretization approach which automatically scales just linearly in n. To circumvent the curse of dimensionality of full tensor product grids, we use the concept of sparse grids. Furthermore, in real-world applications, some embedding directions are usually more important than others and it is reasonable to refine the underlying discretization space only in these directions. To this end, we employ a dimension-adaptive algorithm which is based on the ANOVA (analysis of variance) decomposition of a function. In particular, the reconstruction error is used to measure the quality of an embedding. As an application, the study of large simulation data from an engineering application in the automotive industry (car crash simulation) is performed.

  4. Size Reduction Techniques for Large Scale Permanent Magnet Generators in Wind Turbines

    Science.gov (United States)

    Khazdozian, Helena; Hadimani, Ravi; Jiles, David

    2015-03-01

    Increased wind penetration is necessary to reduce U.S. dependence on fossil fuels, combat climate change and increase national energy security. The U.S Department of Energy has recommended large scale and offshore wind turbines to achieve 20% wind electricity generation by 2030. Currently, geared doubly-fed induction generators (DFIGs) are typically employed in the drivetrain for conversion of mechanical to electrical energy. Yet, gearboxes account for the greatest downtime of wind turbines, decreasing reliability and contributing to loss of profit. Direct drive permanent magnet generators (PMGs) offer a reliable alternative to DFIGs by eliminating the gearbox. However, PMGs scale up in size and weight much more rapidly than DFIGs as rated power is increased, presenting significant challenges for large scale wind turbine application. Thus, size reduction techniques are needed for viability of PMGs in large scale wind turbines. Two size reduction techniques are presented. It is demonstrated that 25% size reduction of a 10MW PMG is possible with a high remanence theoretical permanent magnet. Additionally, the use of a Halbach cylinder in an outer rotor PMG is investigated to focus magnetic flux over the rotor surface in order to increase torque. This work was supported by the National Science Foundation under Grant No. 1069283 and a Barbara and James Palmer Endowment at Iowa State University.

  5. 41 CFR 101-30.701-2 - Item standardization code.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Item standardization code....7-Item Reduction Program § 101-30.701-2 Item standardization code. Item standardization code (ISC) means a code assigned an item in the supply system which identifies the item as authorized...

  6. Comparative Analysis of Pine Needles and Coal for Electricity Generation using Carbon Taxation and Emission Reductions

    Directory of Open Access Journals (Sweden)

    Dhaundiyal Alok

    2015-06-01

    Full Text Available Mitigating global climate change via emission control and taxation is promising for strengthening the economic benefits of bioenergy generation and utilization. This study examines the cost effectiveness of pine needles as an alternative fuel for off-grid electricity generation in India. We first examined the changes of prices in coal for electricity generation due to CO2 emission reductions and taxes using experimental data of gasification plants. The time value of money and depreciation scale were used to find out the real levellized cost of electricity generation of gasification plants. Then, the costs of electricity generation fuelled by pine needles and coal were estimated using the cost analysis method. Our results indicate that pine needles would have more competitive edge than coal if emission had taxed at about an emission tax INR 525.15 Mg-1 of CO2 (US$ 8.4, or higher would be needed for pine needles at a yield of 202.176 dry Mg hm-2 yr. The price of coal used for electricity generation would have significantly increased if global CO2 emission had abridged by 20% or more. However, pine needles were found a much better fuel source with an increasing yield of 5.05 Mg hm-2 yr (with respect to power generation and 2.335 Mg hm-2 yr (with respect to feedstock production.

  7. Agricultural Bio-Fueled Generation of Electricity and Development of Durable and Efficent NOx Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Rodney

    2007-08-08

    The objective of this project was to define the scope and cost of a technology research and development program that will demonstrate the feasibility of using an off-the-shelf, unmodified, large bore diesel powered generator in a grid-connected application, utilizing various blends of BioDiesel as fuel. Furthermore, the objective of project was to develop an emissions control device that uses a catalytic process and BioDiesel (without the presence of Ammonia or Urea)to reduce NOx and other pollutants present in a reciprocating engine exhaust stream with the goal of redefining the highest emission reduction efficiencies possible for a diesel reciprocating generator. Process: Caterpillar Power Generation adapted an off-the-shelf Diesel Generator to run on BioDiesel and various Petroleum Diesel/BioDiesel blends. EmeraChem developed and installed an exhaust gas cleanup system to reduce NOx, SOx, volatile organics, and particulates. The system design and function was optimized for emissions reduction with results in the 90-95% range;

  8. Generating political priority for maternal mortality reduction in 5 developing countries.

    Science.gov (United States)

    Shiffman, Jeremy

    2007-05-01

    I conducted case studies on the level of political priority given to maternal mortality reduction in 5 countries: Guatemala, Honduras, India, Indonesia, and Nigeria. Among the factors that shaped political priority were international agency efforts to establish a global norm about the unacceptability of maternal death; those agencies' provision of financial and technical resources; the degree of cohesion among national safe motherhood policy communities; the presence of national political champions to promote the cause; the deployment of credible evidence to show policymakers a problem existed; the generation of clear policy alternatives to demonstrate the problem was surmountable; and the organization of attention-generating events to create national visibility for the issue. The experiences of these 5 countries offer guidance on how political priority can be generated for other health causes in developing countries.

  9. Simultaneous microbial and electrochemical reductions of vanadium (V) with bioelectricity generation in microbial fuel cells.

    Science.gov (United States)

    Zhang, Baogang; Tian, Caixing; Liu, Ying; Hao, Liting; Liu, Ye; Feng, Chuanping; Liu, Yuqian; Wang, Zhongli

    2015-03-01

    Simultaneous microbial and electrochemical reductions of vanadium (V) with bioelectricity generation were realized in microbial fuel cells (MFCs). With initial V(V) concentrations of 75 mg/l and 150 mg/l in anolyte and catholyte, respectively, stable power output of 419±11 mW/m(2) was achieved. After 12h operation, V(V) concentration in the catholyte decreased to the value similar to that of the initial one in the anolyte, meanwhile it was nearly reduced completely in the anolyte. V(IV) was the main reduction product, which subsequently precipitated, acquiring total vanadium removal efficiencies of 76.8±2.9%. Microbial community analysis revealed the emergence of the new species of Deltaproteobacteria and Bacteroidetes as well as the enhanced Spirochaetes mainly functioned in the anode. This study opens new pathways to successful remediation of vanadium contamination.

  10. Generation IV Nuclear Energy Systems Construction Cost Reductions Through the Use of Virtual Environments

    Energy Technology Data Exchange (ETDEWEB)

    Timothy Shaw; Vaugh Whisker

    2004-02-28

    The objective of this multi-phase project is to demonstrate the feasibility and effectiveness of using full-scale virtual reality simulation in the design, construction, and maintenance of future nuclear power plants. The project will test the suitability of immersive virtual reality technology to aid engineers in the design of the next generation nuclear power plant and to evaluate potential cost reductions that can be realized by optimization of installation and construction sequences. The intent is to see if this type of information technology can be used in capacities similar to those currently filled by full-scale physical mockups. This report presents the results of the completed project.

  11. Modeling Joule Heating Effect on Lunar O2 Generation via Electrolytic Reduction.

    Science.gov (United States)

    Dominquez, Jesus; Poizeau, Sophie; Sibille, Laurent

    2009-01-01

    Kennedy Space Center is leading research work on lunar O2 generation via electrolytic reduction of regolith; the metal oxide present in the regolith is dissociated in oxygen anions and metal cations leading to the generation of gaseous oxygen at the anode and liquid metal at the cathode. Electrical resistance of molten regolith is high, leading to heating of the melt when electrical current is applied between the electrodes (Joule heating). The authors have developed a 3D model using a rigorous approach for two coupled physics (thermal and electrical potential) to not only study the effect of Joule heating on temperature distribution throughout the molten regolith but also to evaluate and optimize the design of the electrolytic cells. This paper presents the results of the thermal analysis performed on the model and used to validate the design of the electrolytic cell.

  12. Friction Reduction of Chrome-Coated Surface with Micro-Dimple Arrays Generated by Electrochemical Micromachining

    Science.gov (United States)

    Chen, Xiaolei; Qu, Ningsong; Hou, Zhibao; Wang, Xiaolei; Zhu, Di

    2017-02-01

    Surface coating and surface texture play a significant role in enhancing the tribological properties of mechanical components. In this study, to further improve the tribological properties of a chrome-coated surface, arrays of circular- and square-shaped micro-dimples were generated on chrome-coated surfaces via electrochemical machining. Through-mask electrochemical micromachining (TMEMM) is a popular electrochemical micromachining method for generating micro-dimple arrays. However, photolithography is a necessary process in conventional TMEMM before electrochemical micromachining, which is time-consuming and expensive when used in mass production. A reusable polydimethylsiloxane mask was introduced to prepare the micro-dimples. Circular micro-dimples of 120 μm diameter and square micro-dimples of 106 μm side length were fabricated on a chrome-coated surface. The results of friction tests indicated that at a load of 220 N, 10 μm deep micro-dimples reduced the coefficient of friction (CoF) significantly compared to an untextured surface. At a load of 320 and 420 N, the CoF continually decreased when the depth of the micro-dimples was increased from 0 to 20 μm. In addition, the results showed that, compared to circular micro-dimples, square micro-dimples contributed to a higher friction reduction ratio under the same conditions. The best friction reduction ratio was found for square dimples with a depth of 20 μm.

  13. NASA's Vision for Potential Energy Reduction from Future Generations of Propulsion Technology

    Science.gov (United States)

    Haller, Bill

    2015-01-01

    Through a robust partnership with the aviation industry, over the past 50 years NASA programs have helped foster advances in propulsion technology that enabled substantial reductions in fuel consumption for commercial transports. Emerging global trends and continuing environmental concerns are creating challenges that will very likely transform the face of aviation over the next 20-40 years. In recognition of this development, NASA Aeronautics has established a set of Research Thrusts that will help define the future direction of the agency's research technology efforts. Two of these thrusts, Ultra-Efficient Commercial Vehicles and Transition to Low-Carbon Propulsion, serve as cornerstones for the Advanced Air Transport Technology (AATT) project. The AATT project is exploring and developing high-payoff technologies and concepts that are key to continued improvement in energy efficiency and environmental compatibility for future generations of fixed-wing, subsonic transports. The AATT project is primarily focused on the N+3 timeframe, or 3 generations from current technology levels. As should be expected, many of the propulsion system architectures technologies envisioned for N+3 vary significantly from todays engines. The use of batteries in a hybrid-electric configuration or deploying multiple fans distributed across the airframe to enable higher bypass ratios are just two examples of potential advances that could enable substantial energy reductions over current propulsion systems.

  14. The Parent Psychological Flexibility Questionnaire (PPFQ: Item Reduction and Validation in a Clinical Sample of Swedish Parents of Children with Chronic Pain

    Directory of Open Access Journals (Sweden)

    Camilla Wiwe Lipsker

    2016-11-01

    Full Text Available In pediatric chronic pain, research indicates a positive relation between parental psychological flexibility (i.e., the parent’s willingness to experience distress related to the child’s pain in the service of valued behavior and level of functioning in the child. This points to the utility of targeting parental psychological flexibility in pediatric chronic pain. The Parent Psychological Flexibility Questionnaire (PPFQ is currently the only instrument developed for this purpose, and two previous studies have indicated its reliability and validity. The current study sought to validate the Swedish version of the 17-item PPFQ (PPFQ-17 in a sample of parents (n = 263 of children with chronic pain. Factor structure and internal reliability were evaluated by means of principal component analysis (PCA and Cronbach’s alpha. Concurrent criterion validity was examined by hierarchical multiple regression analyses with parental anxiety and depression as outcomes. The PCA supported a three-factor solution with 10 items explaining 69.5% of the total variance. Cronbach’s alpha (0.86 indicated good internal consistency. The 10-item PPFQ (PPFQ-10 further explained a significant amount of variance in anxiety (29%, and depression (35.6%, confirming concurrent validity. In conclusion, results support the reliability and validity of the PPFQ-10, and suggest its usefulness in assessing psychological flexibility in parents of children with chronic pain.

  15. Concurrent ethene generation and growth of Dehalococcoides containing vinyl chloride reductive dehalogenase genes during an enhanced reductive dechlorination field demonstration

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Durant, N. D.; Dennis, P.;

    2008-01-01

    Dehalococcoides bacteria that produce catabolic vinyl chloride (VC) reductive dehalogenase enzymes have been implicated as a requirement for successful biological dechlorination of VC to ethene in groundwater systems. Therefore, the functional genes in Dehalococcoides that produce VC reductase (e...

  16. AN EFFICIENT DATA MINING METHOD TO FIND FREQUENT ITEM SETS IN LARGE DATABASE USING TR- FCTM

    Directory of Open Access Journals (Sweden)

    Saravanan Suba

    2016-01-01

    Full Text Available Mining association rules in large database is one of most popular data mining techniques for business decision makers. Discovering frequent item set is the core process in association rule mining. Numerous algorithms are available in the literature to find frequent patterns. Apriori and FP-tree are the most common methods for finding frequent items. Apriori finds significant frequent items using candidate generation with more number of data base scans. FP-tree uses two database scans to find significant frequent items without using candidate generation. This proposed TR-FCTM (Transaction Reduction- Frequency Count Table Method discovers significant frequent items by generating full candidates once to form frequency count table with one database scan. Experimental results of TR-FCTM shows that this algorithm outperforms than Apriori and FP-tree.

  17. Reduction of Cogging Torque in Dual Rotor Permanent Magnet Generator for Direct Coupled Wind Energy Systems

    Directory of Open Access Journals (Sweden)

    Sivachandran Paulsamy

    2014-01-01

    Full Text Available In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG for direct coupled stand alone wind energy systems (SAWES. Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions.

  18. Reduction of cogging torque in dual rotor permanent magnet generator for direct coupled wind energy systems.

    Science.gov (United States)

    Paulsamy, Sivachandran

    2014-01-01

    In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand alone wind energy systems (SAWES). Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions.

  19. Generation process of FeS and its inhibition mechanism on iron mineral reduction in selective direct reduction of laterite nickel ore

    Institute of Scientific and Technical Information of China (English)

    Zhi-guo Liu; Ti-chang Sun; Xiao-ping Wang; En-xia Gao

    2015-01-01

    Numerous studies have demonstrated that Na2SO4 can significantly inhibit the reduction of iron oxide in the selective reduction process of laterite nickel ore. FeS generated in the process plays an important role in selective reduction, but the generation process of FeS and its inhibition mechanism on iron reduction are not clear. To figure this out, X-ray diffraction and scanning electron microscopy analyses were conducted to study the roasted ore. The results show that when Na2SO4 is added in the roasting, the FeO content in the roasted ore in-creases accompanied by the emergence of FeS phase. Further analysis indicates that Na2S formed by the reaction of Na2SO4 with CO reacts with SiO2 at the FeO surface to generate FeS and Na2Si2O5. As a result, a thin film forms on the surface of FeO, hindering the contact be-tween reducing gas and FeO. Therefore, the reduction of iron is depressed, and the FeO content in the roasted ore increases.

  20. Cathodic reduction of hexavalent chromium [Cr(VI)] coupled with electricity generation in microbial fuel cells.

    Science.gov (United States)

    Wang, Gang; Huang, Liping; Zhang, Yifeng

    2008-11-01

    A novel approach to Cr(VI)-contaminated wastewater treatment was investigated using microbial fuel cell technologies in fed-batch mode. By using synthetic Cr(VI)-containing wastewater as catholyte and anaerobic microorganisms as anodic biocatalyst, Cr(VI) at 100 mg/l was completely removed during 150 h (initial pH 2). The maximum power density of 150 mW/m(2) (0.04 mA/cm(2)) and the maximum open circuit voltage of 0.91 V were generated with Cr(VI) at 200 mg/l as electron acceptor. This work verifies the possibility of simultaneous electricity production and cathodic Cr(VI) reduction.

  1. Noise floor reduction of an Er:fiber laser-based photonic microwave generator

    CERN Document Server

    Jiang, Haifeng; Quinlan, Franklyn; Fortier, Tara; Diddams, Scott A

    2011-01-01

    The generation of microwaves from optical signals suffers from thermal and shot noise inherent in the photodetection process. This problem is more acute at lower pulse repetition rates where photodiode saturation limits the achievable signal-to-noise ratio. In this paper, we demonstrate a 10-15 dB reduction in the 10 GHz phase noise floor by multiplication of the pulse repetition rate. Starting with a 250 MHz fundamentally mode-locked erbium(Er):fiber laser, we compare two different approaches to repetition rate multiplication: Fabry-Perot cavity filtering and a cascaded, unbalanced Mach-Zehnder fiber-based interferometer. These techniques reduce the phase noise floor on the 10 GHz photodetected harmonic to -158 dBc/Hz and -162 dBc/Hz, respectively, for Fourier frequencies higher than 100 kHz.

  2. On a hypothetical generational relationship between HCN and constituents of the reductive citric acid cycle.

    Science.gov (United States)

    Eschenmoser, Albert

    2007-04-01

    Encouraged by observations made on the course of reactions the HCN-tetramer can undergo with acetaldehyde, I delineate a constitutional and potentially generational relationship between HCN and those constituents of the reductive citric acid cycle that are direct precursors of amino acids in contemporary metabolism. In this context, the robustness postulate of classical prebiotic chemistry is questioned, and, by an analysis of the (hypothetical) reaction-tree of a stepwise hydrolysis of the HCN-tetramer, it is shown how such a non-robust chemical reaction platform could harbor the potential for the emergence of autocatalytic cycles. It is concluded that the chemistry of HCN should be revisited by focussing on its non-robust parts in order to demonstrate its full potential as one of the possible roots of prebiotic self-organizing chemical processes.

  3. Reduction of greenhouse-gas emissions by utilization of superconductivity in electric-power generation

    Energy Technology Data Exchange (ETDEWEB)

    Hartikainen, T.; Lehtonen, J.; Mikkonen, R. [Tampere University of Technology (Finland). Institute of Electromagnetics

    2004-06-01

    The reduction of greenhouse-gas (GHG) emissions is becoming a topical issue due to the Kyoto Protocol which requires the European Union (EU) to reduce its emissions by 8% from the 1990 levels by between 2008 and 2012. The main source for GHG-emissions is energy production. Superconducting electrical machinery is starting to emerge into the market of power devices. High-temperature superconducting (HTS) windings in generators and transformers can approximately halve the losses compared to conventional devices. Higher efficiency saves electrical energy and also reduces GHG-emissions as well. In this paper, the reduction potential of GHG-emissions in the EU by HTS-machinery is calculated. The replacement of existing devices by HTS ones is considered from the environmental point-of- view. The structure of energy production for the EU was investigated and the emission data from different type of power plants were screened. The potential energy savings were converted to saved GHG-emission tonnes. (author)

  4. Reduction theories elucidate the origins of complex biological rhythms generated by interacting delay-induced oscillations.

    Directory of Open Access Journals (Sweden)

    Ikuhiro Yamaguchi

    Full Text Available Time delay is known to induce sustained oscillations in many biological systems such as electroencephalogram (EEG activities and gene regulations. Furthermore, interactions among delay-induced oscillations can generate complex collective rhythms, which play important functional roles. However, due to their intrinsic infinite dimensionality, theoretical analysis of interacting delay-induced oscillations has been limited. Here, we show that the two primary methods for finite-dimensional limit cycles, namely, the center manifold reduction in the vicinity of the Hopf bifurcation and the phase reduction for weak interactions, can successfully be applied to interacting infinite-dimensional delay-induced oscillations. We systematically derive the complex Ginzburg-Landau equation and the phase equation without delay for general interaction networks. Based on the reduced low-dimensional equations, we demonstrate that diffusive (linearly attractive coupling between a pair of delay-induced oscillations can exhibit nontrivial amplitude death and multimodal phase locking. Our analysis provides unique insights into experimentally observed EEG activities such as sudden transitions among different phase-locked states and occurrence of epileptic seizures.

  5. Reductions in greenhouse gas (GHG) generation and energy consumption in wastewater treatment plants.

    Science.gov (United States)

    Yerushalmi, L; Ashrafi, O; Haghighat, F

    2013-01-01

    Greenhouse gas (GHG) emission and energy consumption by on-site and off-site sources were estimated in two different wastewater treatment plants that used physical-chemical or biological processes for the removal of contaminants, and an anaerobic digester for sludge treatment. Physical-chemical treatment processes were used in the treatment plant of a locomotive repair factory that processed wastewater at 842 kg chemical oxygen demand per day. Approximately 80% of the total GHG emission was related to fossil fuel consumption for energy production. The emission of GHG was reduced by 14.5% with the recovery of biogas that was generated in the anaerobic digester and its further use as an energy source, replacing fossil fuels. The examined biological treatment system used three alternative process designs for the treatment of effluents from pulp and paper mills that processed wastewater at 2,000 kg biochemical oxygen demand per day. The three designs used aerobic, anaerobic, or hybrid aerobic/anaerobic biological processes for the removal of carbonaceous contaminants, and nitrification/denitrification processes for nitrogen removal. Without the recovery and use of biogas, the aerobic, anaerobic, and hybrid treatment systems generated 3,346, 6,554 and 7,056 kg CO(2)-equivalent/day, respectively, while the generated GHG was reduced to 3,152, 6,051, and 6,541 kg CO(2)-equivalent/day with biogas recovery. The recovery and use of biogas was shown to satisfy and exceed the energy needs of the three examined treatment plants. The reduction of operating temperature of the anaerobic digester and anaerobic reactor by 10°C reduced energy demands of the treatment plants by 35.1, 70.6 and 62.9% in the three examined treatment systems, respectively.

  6. Optimal item pool design for computerized adaptive tests with polytomous items using GPCM

    Directory of Open Access Journals (Sweden)

    Xuechun Zhou

    2014-09-01

    Full Text Available Computerized adaptive testing (CAT is a testing procedure with advantages in improving measurement precision and increasing test efficiency. An item pool with optimal characteristics is the foundation for a CAT program to achieve those desirable psychometric features. This study proposed a method to design an optimal item pool for tests with polytomous items using the generalized partial credit model (G-PCM. It extended a method for approximating optimality with polytomous items being described succinctly for the purpose of pool design. Optimal item pools were generated using CAT simulations with and without practical constraints of content balancing and item exposure control. The performances of the item pools were evaluated against an operational item pool. The results indicated that the item pools designed with stratification based on discrimination parameters performed well with an efficient use of the less discriminative items within the target accuracy levels. The implications for developing item pools are also discussed.

  7. Sharing the cost of redundant items

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Moulin, Hervé

    2014-01-01

    are network connectivity problems when an existing (possibly inefficient) network must be maintained. We axiomatize a family cost ratios based on simple liability indices, one for each agent and for each item, measuring the relative worth of this item across agents, and generating cost allocation rules......We ask how to share the cost of finitely many public goods (items) among users with different needs: some smaller subsets of items are enough to serve the needs of each user, yet the cost of all items must be covered, even if this entails inefficiently paying for redundant items. Typical examples...... additive in costs....

  8. A Conservation Voltage Reduction Scheme for a Distribution Systems with Intermittent Distributed Generators

    Directory of Open Access Journals (Sweden)

    Pyeong-Ik Hwang

    2016-08-01

    Full Text Available In this paper, a conservation voltage reduction (CVR scheme is proposed for a distribution system with intermittent distributed generators (DGs, such as photovoltaics and wind turbines. The CVR is a scheme designed to reduce energy consumption by lowering the voltages supplied to customers. Therefore, an unexpected under-voltage violation can occur due to the variation of active power output from the intermittent DGs. In order to prevent the under-voltage violation and improve the CVR effect, a new reactive power controller which complies with the IEEE Std. 1547TM, and a parameter determination method for the controller are proposed. In addition, an optimal power flow (OPF problem to determine references for the resources of CVR is formulated with consideration of the intermittent DGs. The proposed method is validated using a modified IEEE 123-node test feeder. With the proposed method, the voltages of the test system are maintained to be greater than the lower bound, even though the active power outputs of the DGs are varied. Moreover, the CVR effect is improved compared to that used with the conventional reactive power control methods.

  9. Optimal Placement and Sizing of Distributed Generation And Capacitor Bank For Loss Reduction And Reliability Improvement In Distribution Systems

    OpenAIRE

    Reza Baghipourr; Seyyed Mehdi Hosseini

    2014-01-01

    In this paper optimum size and location of the capacitors and distributed generators (DGs) are determined for reliability improvement and power loss reduction using genetic algorithm (GA). The main innovation of this paper is using both DG and Capacitor for the reliability improvement and power loss reduction. For this purpose an objective function consisting of reliability cost, power loss cost and also DG's and capacitor's investment cost are considered. The effectiveness of the proposed me...

  10. Health marketing in the supermarket: using prompting, product sampling, and price reduction to increase customer purchases of lower-fat items.

    Science.gov (United States)

    Paine-Andrews, A; Francisco, V T; Fawcett, S B; Johnston, J; Coen, S

    1996-01-01

    Reducing purchase and consumption of higher-fat foods is an important health objective for the nation since these behaviors are associated with cardiovascular disease and some cancers. Public health agents attempt to promote health-related behaviors, such as purchases of lower-fat foods, by changing key features of relevant environments. This study examined the effects of a marketing intervention in a supermarket on customer purchases of lower-fat products. Customers of one store of a major supermarket chain participated in this study. Direct observations of customer purchases of lower-fat milk, salad dressings, and frozen desserts were conducted. The supermarket intervention consisted of prompting, product sampling, and price reduction (store coupons). Using an interrupted time series design with switching replications, we found low to moderate increases for the lower-fat counterparts of milk, frozen desserts, and salad dressing. The greatest increase in purchases was found with frozen desserts. Findings from this study suggest that prompting, product sampling, and price reduction can increase customer purchases of some lower-fat products. Implications of these findings for the development and evaluation of health marketing interventions are discussed.

  11. Determination of Inorganic Arsenic Species by Electrochemical Hydride Generation Atomic Absorption Spectrometry with Selective Electrochemical Reduction

    Institute of Scientific and Technical Information of China (English)

    LI Xun; WANG Zheng-Hao

    2007-01-01

    A new direct procedure for the determination of inorganic arsenic species was developed by electrochemical hydride generation atomic absorption spectrometry (EcHG-AAS) with selective electrochemical reduction. The determination of inorganic arsenic species is based on the fact that As(Ⅲ) shows significantly higher absorbance at low electrolytic currents than As(Ⅴ) in 0.3 mol·L-1 H2SO4.The electrolytic current used for the determination of As(Ⅲ) without considerable interferences of As(V) was 0.4 A, whereas the current for the determination of As(Ⅲ)and As(V) was 1.2 A. For equal concentrations of As(Ⅲ) and As(V) in a sample, the interferences of As(V) during the As(Ⅲ) determination were smaller than 5%. The absorbance for As(V) could be calculated by subtracting that for As(Ⅲ) measured at 0.4 A from the total absorbance for As(Ⅲ) and As(V) measured at 1.2 A, and then the concentration of As(V) can be obtained by its calibration curve at 1.2 A. The methodology developed provided the detection limits of 0.3 and 0.6 ng·ml-1 for As(Ⅲ) and As(V) respectively.The relative standrad deviations were of 3.5% for 20 ng·ml-1 As(Ⅲ) and 302% for 20 ng·ml-1 As(V).The method was successfully applied to determination of soluble inorganic arsenic species in Chinese medicine.

  12. Medical waste: reducing its generation.

    Science.gov (United States)

    Belkin, N L

    1993-01-01

    1. Materials that can be recycled have yet to be proven to be a more cost-effective means of reducing medical waste. The literature indicates that the efficacy of reusable textiles is at least equal to that of some disposables--and reusable items reduce the generation of blood-contaminated waste. 2. The perioperative nursing community should consider replacing single-use items with materials intended for multiple uses. 3. "Source reduction" entails the replacement of single-use items with reusable items. Successful source-reduction programs require changes in individual and collective behavior patterns. 4. Recycling of materials renders them suitable for another use in a product similar to that in which they were originally used. On the other hand, reprocessing is an all-descriptive term of what must be done to an item to render it suitable for another identical use.

  13. 基于降价销售的EOQ模型下易变质商品库存分析%Analysis of Deteriorating Items Inventory under Economic Order Quantity Model Based on Price Reduction Sale

    Institute of Scientific and Technical Information of China (English)

    陈玲; 朱静

    2012-01-01

    This article has established Economic Order Quantity (EOQ) Model for price reduction sale of deteriorating items by taking demand as a constant, explains the existence of the optimal solution to the model, introduces the method for the optimal solution and provides theoretical basis for the promotion of deteriorating commodities.%建立了需求为常数的易变质商品降价促销的EOQ模型,对模型最优解的存在性进行了说明,并介绍了求最优解的方法,为易变质商品的促销提供理论依据。

  14. Estimating the Reduction of Generating System CO2 Emissions Resulting from Significant Wind Energy Penetration

    Energy Technology Data Exchange (ETDEWEB)

    Holttinen, Hannele; Kiviluoma, Juha; Pineda, Ivan; McCann, John; Clancy, Matthew; Milligan, Michael

    2014-11-13

    This paper presents ways of estimating CO2 reductions of wind power using different methodologies. The paper discusses pitfalls in methodology and proposes appropriate methods to perform the calculations. Results for CO2 emission reductions are shown from several countries. This paper is an international collaboration of IEA Wind Task 25 on wind integration.

  15. Sulphur dioxide reduction by electrochemically generated Ti{sup III} species

    Energy Technology Data Exchange (ETDEWEB)

    Cservenyak, I.; Kelsall, G.H.; Wang, W. [Imperial College, London (United Kingdom). Dept. of Earth Resources Engineering

    1995-12-31

    The kinetics and mechanism of the electrochemical and chemical reduction of aqueous sulfur dioxide are outlined, since reactions such as: SO{sub 2}(g) + 4Ti{sup 3+} + 2H{sub 2}O {yields} `S` + 4TiO{sup 2+} + 4H{sup +} could form the basis of novel indirect electrochemical reduction process for the desulfurisation of SO{sub 2}-containing flue gases. After separation of the sulfur, the aqueous phase would be recycled to the electrochemical reactor for regeneration of the Ti{sup III} reductant from the Ti{sup IV} precursors in the envisaged process. 15 refs., 5 figs.

  16. Faculty development on item writing substantially improves item quality.

    Science.gov (United States)

    Naeem, Naghma; van der Vleuten, Cees; Alfaris, Eiad Abdelmohsen

    2012-08-01

    The quality of items written for in-house examinations in medical schools remains a cause of concern. Several faculty development programs are aimed at improving faculty's item writing skills. The purpose of this study was to evaluate the effectiveness of a faculty development program in item development. An objective method was developed and used to assess improvement in faculty's competence to develop high quality test items. This was a quasi experimental study with a pretest-midtest-posttest design. A convenience sample of 51 faculty members participated. Structured checklists were used to assess the quality of test items at each phase of the study. Group scores were analyzed using repeated measures analysis of variance. The results showed a significant increase in participants' mean scores on Multiple Choice Questions, Short Answer Questions and Objective Structured Clinical Examination checklists from pretest to posttest (p development are generally lacking in quality. It also provides evidence of the value of faculty development in improving the quality of items generated by faculty.

  17. On-line pre-reduction of Se(VI) by thiourea for selenium speciation by hydride generation

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Jianhua [Department of Chemistry and the MOE Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (China); Wang Qiuquan [Department of Chemistry and the MOE Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (China)]. E-mail: qqwang@xmu.edu.cn; Ma Yuning [Department of Chemistry and the MOE Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (China); Yang Limin [Department of Chemistry and the MOE Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (China); Huang Benli [Department of Chemistry and the MOE Key Laboratory of Analytical Sciences, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (China)

    2006-07-15

    In this study, thiourea (TU) was novelly developed as a reduction reagent for on-line pre-reduction of selenium(VI) before conventional hydride generation (HG) by KBH{sub 4}/NaOH-HCl. After TU on-line pre-reduction, the HG efficiency of Se(VI) has been greatly improved and because even higher than that of the same amount of Se(IV) obtained in the conventional HG system. The possible pre-reduction mechanism is discussed. The detection limit (DL) of selenate reaches 10 pg mL{sup -1} when using on-line TU pre-reduction followed by HG atomic fluorescence detection. When TU pre-reduction followed by HG is used as an interface between ion-pair high performance liquid chromatography and atomic fluorescence spectrometry, selenocystine, selenomethionine, selenite and selenate can be measured simultaneously and quantitatively. The DLs of these are 0.06, 0.08, 0.05 and 0.04 ng mL{sup -1}, respectively, and the relative standard deviations of 9 duplicate runs for all the 4 species are less than 5%. Furthermore, it was successfully applied to Se speciation analysis of cultured garlic samples, and validated by determination of total selenium and selenium species in certified reference material NIST 1946.

  18. Screening Test Items for Differential Item Functioning

    Science.gov (United States)

    Longford, Nicholas T.

    2014-01-01

    A method for medical screening is adapted to differential item functioning (DIF). Its essential elements are explicit declarations of the level of DIF that is acceptable and of the loss function that quantifies the consequences of the two kinds of inappropriate classification of an item. Instead of a single level and a single function, sets of…

  19. Redox behaviour of nifuroxazide: generation of the one-electron reduction product.

    Science.gov (United States)

    Squella, J A; Letelier, M E; Lindermeyer, L; Nuñez-Vergara, L J

    1996-01-05

    The electrochemical properties of nifuroxazide have been investigated in aqueous and aqueous-DMF mixed solvents. In aqueous media, a single, irreversible four-electron reduction occurs to give the hydroxylamine derivative. In mixed media, a reversible one-electron reduction to form a nitro radical anion takes place. Cyclic voltammetric studies show that the anion radical product is stable, although the nitro radical anion intermediate shows a tendency to undergo further chemical reactions. A comparison with the voltammetric behaviour of other nitrofurans such as nifurtimox, nitrofurazone and furazolidone is made. The electrochemically-obtained parameters are correlated with the in vivo studies of oxygen consumption on Trypanosoma cruzi cell suspensions.

  20. A molecular copper catalyst for electrochemical water reduction with a large hydrogen-generation rate constant in aqueous solution.

    Science.gov (United States)

    Zhang, Peili; Wang, Mei; Yang, Yong; Yao, Tianyi; Sun, Licheng

    2014-12-08

    The copper complex [(bztpen)Cu](BF4)2 (bztpen=N-benzyl-N,N',N'-tris(pyridin-2-ylmethyl)ethylenediamine) displays high catalytic activity for electrochemical proton reduction in acidic aqueous solutions, with a calculated hydrogen-generation rate constant (k(obs)) of over 10000 s(-1). A turnover frequency (TOF) of 7000 h(-1) cm(-2) and a Faradaic efficiency of 96% were obtained from a controlled potential electrolysis (CPE) experiment with [(bztpen)Cu](2+) in pH 2.5 buffer solution at -0.90 V versus the standard hydrogen electrode (SHE) over two hours using a glassy carbon electrode. A mechanism involving two proton-coupled reduction steps was proposed for the dihydrogen generation reaction catalyzed by [(bztpen)Cu](2+).

  1. Water withdrawal and consumption reduction analysis for electrical energy generation system

    Science.gov (United States)

    Nouri, Narjes

    There is an increasing concern over shrinking water resources. Water use in the energy sector primarily occurs in electricity generation. Anticipating scarcer supplies, the value of water is undoubtedly on the rise and design, implementation, and utilization of water saving mechanisms in energy generation systems are becoming inevitable. Most power plants generate power by boiling water to produce steam to spin electricity-generating turbines. Large quantities of water are often used to cool the steam in these plants. As a consequence, most fossil-based power plants in addition to consuming water, impact the water resources by raising the temperature of water withdrawn for cooling. A comprehensive study is conducted in this thesis to analyze and quantify water withdrawals and consumption of various electricity generation sources such as coal, natural gas, renewable sources, etc. Electricity generation for the state of California is studied and presented as California is facing a serious drought problem affecting more than 30 million people. Integrated planning for the interleaved energy and water sectors is essential for both water and energy savings. A linear model is developed to minimize the water consumption while considering several limitations and restrictions. California has planned to shut down some of its hydro and nuclear plants due to environmental concerns. Studies have been performed for various electricity generation and water saving scenarios including no-hydro and no-nuclear plant and the results are presented. Modifications to proposed different scenarios have been applied and discussed to meet the practical and reliability constraints.

  2. Electricity generation and bivalent copper reduction as a function of operation time and cathode electrode material in microbial fuel cells

    Science.gov (United States)

    Wu, Dan; Huang, Liping; Quan, Xie; Li Puma, Gianluca

    2016-03-01

    The performance of carbon rod (CR), titanium sheet (TS), stainless steel woven mesh (SSM) and copper sheet (CS) cathode materials are investigated in microbial fuel cells (MFCs) for simultaneous electricity generation and Cu(II) reduction, in multiple batch cycle operations. After 12 cycles, the MFC with CR exhibits 55% reduction in the maximum power density and 76% increase in Cu(II) removal. In contrast, the TS and SSM cathodes at cycle 12 show maximum power densities of 1.7 (TS) and 3.4 (SSM) times, and Cu(II) removal of 1.2 (TS) and 1.3 (SSM) times higher than those observed during the first cycle. Diffusional resistance in the TS and SSM cathodes is found to appreciably decrease over time due to the copper deposition. In contrast to CR, TS and SSM, the cathode made with CS is heavily corroded in the first cycle, exhibiting significant reduction in both the maximum power density and Cu(II) removal at cycle 2, after which the performance stabilizes. These results demonstrate that the initial deposition of copper on the cathodes of MFCs is crucial for efficient and continuous Cu(II) reduction and electricity generation over prolonged time. This effect is closely associated with the nature of the cathode material. Among the materials examined, the SSM is the most effective and inexpensive cathode for practical use in MFCs.

  3. Strategies for Mitigating the Reduction in Economic Value of Variable Generation with Increasing Penetration Levels

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Andrew; Wiser, Ryan

    2014-03-03

    In this report, we evaluate individual options that have the potential to stem the decline in the marginal value of variable generation (VG) with increasing penetration levels. We focus only on the effectiveness of mitigation measures for wind and PV.

  4. New approaches for the reduction of plasma arc drop in second-generation thermionic converters

    Science.gov (United States)

    Hatziprokopiou, M. E.; Shaw, D. T.

    1981-03-01

    Investigations of ion generation and recombination mechanisms in the cesium plasma are described with respect to the advanced mode thermionic energy converter. The changes in plasma density and temperature within the converter were studied under the influence of several promising auxiliary ionization candidate sources. Three novel approaches of external cesium ion generation were studied in some detail, namely vibrationally excited N2 as an energy source of ionization of Cs ions in a dc discharge, microwave power as a means of resonant sustenance of the cesium plasma, and ion generation in a pulse N2-Cs mixture. The data obtained show that all three techniques - i.e., the non-LTE high voltage pulsing, the energy transfer from vibrationally excited diatomic gases, and the external pumping with a microwave power have considerable promise as schemes in auxiliary ion generation applicable to the advanced thermionic energy converter.

  5. Hematite Reduction Buffers Acid Generation and Enhances Nutrient Uptake by a Fermentative Iron Reducing Bacterium, Orenia metallireducens Strain Z6.

    Science.gov (United States)

    Dong, Yiran; Sanford, Robert A; Chang, Yun-Juan; McInerney, Michael J; Fouke, Bruce W

    2017-01-03

    Fermentative iron-reducing organisms have been identified in a variety of environments. Instead of coupling iron reduction to respiration, they have been consistently observed to use ferric iron minerals as an electron sink for fermentation. In the present study, a fermentative iron reducer, Orenia metallireducens strain Z6, was shown to use iron reduction to enhance fermentation not only by consuming electron equivalents, but also by generating alkalinity that effectively buffers the pH. Fermentation of glucose by this organism in the presence of a ferric oxide mineral, hematite (Fe2O3), resulted in enhanced glucose decomposition compared with fermentation in the absence of an iron source. Parallel evidence (i.e., genomic reconstruction, metabolomics, thermodynamic analyses, and calculation of electron transfer) suggested hematite reduction as a proton-consuming reaction effectively consumed acid produced by fermentation. The buffering effect of hematite was further supported by a greater extent of glucose utilization by strain Z6 in media with increasing buffer capacity. Such maintenance of a stable pH through hematite reduction for enhanced glucose fermentation complements the thermodynamic interpretation of interactions between microbial iron reduction and other biogeochemical processes. This newly discovered feature of iron reducer metabolism also has significant implications for groundwater management and contaminant remediation by providing microbially mediated buffering systems for the associated microbial and/or chemical reactions.

  6. Stoner versus Heisenberg: Ultrafast exchange reduction and magnon generation during laser-induced demagnetization

    Science.gov (United States)

    Turgut, Emrah; Zusin, Dmitriy; Legut, Dominik; Carva, Karel; Knut, Ronny; Shaw, Justin M.; Chen, Cong; Tao, Zhensheng; Nembach, Hans T.; Silva, Thomas J.; Mathias, Stefan; Aeschlimann, Martin; Oppeneer, Peter M.; Kapteyn, Henry C.; Murnane, Margaret M.; Grychtol, Patrik

    2016-12-01

    Understanding how the electronic band structure of a ferromagnetic material is modified during laser-induced demagnetization on femtosecond time scales has been a long-standing question in condensed matter physics. Here, we use ultrafast high harmonics to measure time-, energy-, and angle-resolved M -edge magnetic asymmetry spectra for Co films after optical pumping to induce ultrafast demagnetization. This provides a complete data set that we can compare with advanced ab initio magneto-optical calculations. Our analysis identifies that the dominant mechanisms contributing to ultrafast demagnetization on time scales up to several picoseconds are a transient reduction in the exchange splitting and the excitation of ultrafast magnons. Surprisingly, we find that the magnon contribution to ultrafast demagnetization is already strong on subpicosecond time scales, while the reduction in exchange splitting persists to several picoseconds.

  7. Efficient Generation of Chemiluminescence during the reduction of manganese(IV) ions with lactic acid

    Science.gov (United States)

    Tsaplev, Yu. B.

    2016-12-01

    The kinetics and mechanism of chemiluminescence during the reduction of manganese(IV) ions with lactic acid in an H2SO4-AcOH medium are studied. Kinetic spectrophotometric measurements are used to determine the profiles of change in the concentrations of Mn(IV) and Mn(III) ions during the reaction. The results from kinetic spectrophotometric measurements are compared to the light yield kinetics. The quantum chemiluminescence and chemiexcitation yields reach record values.

  8. PAPR Reduction Approach Based on Channel Estimation Pilots for Next Generations Broadcasting Systems

    Directory of Open Access Journals (Sweden)

    Anh-Tai Ho

    2011-01-01

    Full Text Available A novel peak-to-average power ratio (PAPR reduction technique for orthogonal frequency division multiplexing (OFDM systems is addressed. Instead of using dedicated pilots for PAPR reduction as with tone reservation (TR method selected by the DVB-T2 standard, we propose to use existing pilots used for channel estimation. In this way, we avoid the use of reserved tone pilots and then improve the spectral efficiency of the system. In order to allow their recovery at the receiver, these pilots have to follow particular laws which permit their blind detection and avoid sending side information. In this work, we propose and investigate a multiplicative law operating in discrete frequency domain. The operation in discrete domain aims at reducing degradation due to detection and estimation error in continuous domain. Simulation results are performed using the new DVB-T2 standard parameters. Its performance is compared to the DVB-T2 PAPR gradient algorithm and to the second-order cone programming (SOCP competitive technique proposed in the literature. We show that the proposed technique is efficient in terms of PAPR reduction value and of spectral efficiency while the channel estimation performance is maintained.

  9. Antimony speciation in soils: improving the detection limits using post-column pre-reduction hydride generation atomic fluorescence spectroscopy (HPLC/pre-reduction/HG-AFS).

    Science.gov (United States)

    Quiroz, Waldo; Olivares, David; Bravo, Manuel; Feldmann, Jorg; Raab, Andrea

    2011-04-15

    HG-AFS is highly sensitive and low cost detection system and its use for antimony chemical speciation coupled to HPLC is gaining popularity. However speciation analysis in soils is strongly hampered because the most efficient extractant reported in the literature (oxalic acid) strongly inhibits the generation of SbH(3) by Sb(V), the major species in this kind of matrix, severely affecting its detection limits. The purpose of this research is to reduce the detection limit of Sb(V), by using a post column on-line reduction system with l-cysteine reagent (HPLC/pre-reduction/HG-AFS). The system was optimized by experimental design, optimum conditions found were 2% (w/v) and 10°C temperature coil. Detection limits of Sb(V) and Sb(III) in oxalic acid (0.25 mol L(-1)) were improved from 0.3 and 0.1 μg L(-1) to 0.07 and 0.07 μg L(-1), respectively. The methodology developed was applied to Chilean soils, where Sb(V) was the predominant species. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Generation IV Nuclear Energy Systems Construction Cost Reductions through the Use of Virtual Environments - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Timothy Shaw; Anthony Baratta; Vaughn Whisker

    2005-02-28

    Final report of 3 year DOE NERI-sponsored effort evaluating immersive virtual reality (CAVE) technology for design review, construction planning, and maintenance planning and training for next generation nuclear power plants. Program covers development of full-scale virtual mockups generated from 3D CAD data presented in a CAVE visualization facility. Mockups applied to design review of AP600/1000, Construction planning for AP 600, and AP 1000 maintenance evaluation. Proof of concept study also performed for GenIV PBMR models.

  11. Effect of Set Potential on Hexavalent Chromium Reduction and Electricity Generation from Biocathode Microbial Fuel Cells

    KAUST Repository

    Huang, Liping

    2011-06-01

    Setting a biocathode potential at ?300 mV improved the subsequent performance of an MFC for Cr(VI) reduction compared to a control (no set potential). With this set potential, the startup time was reduced to 19 days, the reduction of Cr(VI) was improved to 19.7 mg/L d, and the maximum power density was increased to 6.4 W/m3 compared to the control (26 days, 14.0 mg/L d and 4.1 W/m3). Set potentials of ?150 mV and ?300 mV also improved system performance and led to similarly higher utilization of metabolic energy gained (PMEG) than set potentials of +200 mV and ?450 mV. We observed putative pili at ?150 and ?300 mV potentials, and aggregated precipitates on bacterial surfaces in both poised and nonpoised controls. These tests show that there are optimal potentials that can be set for developing a Cr(VI) biocathode. © 2011 American Chemical Society.

  12. Generation of tobacco lines with widely different reduction in nicotine levels via RNA silencing approaches

    Indian Academy of Sciences (India)

    Peng Wang; Zhifeng Liang; Jia Zeng Wenchao; Wenchao Li; Xiaofen Sun; Zhiqi Miao; Kexuan Tang

    2008-06-01

    Issues related to the nicotine content of tobacco have been public concerns. Several reports have described decreasing nicotine levels by silencing the putrescine N-methyltransferase (PMT) genes, but the reported variations of nicotine levels among transgenic lines are relatively low in general. Here we describe the generation in tobacco (Nicotiana tabacum) lines with widely different, reduced nicotine levels using three kinds of RNA-silencing approaches. The relative efficacies of suppression were compared among the three approaches regarding the aspect of nicotine level in tobacco leaves. By suppressing expression of the PMT genes, over 200 transgenic lines were obtained with nicotine levels reduced by 9.1–96.7%. RNA interference (RNAi) was the most efficient method of reducing the levels of nicotine, whereas cosuppression and antisense methods were less effective. This report gives clues to the efficient generation of plants with a variety of metabolite levels, and the results demonstrate the relative efficiencies of various RNA-silencing methods.

  13. Reduction of Lattice Thermal Conductivity in PbTe Induced by Artificially Generated Pores

    Directory of Open Access Journals (Sweden)

    Jae-Yeol Hwang

    2015-01-01

    Full Text Available Highly dense pore structure was generated by simple sequential routes using NaCl and PVA as porogens in conventional PbTe thermoelectric materials, and the effect of pores on thermal transport properties was investigated. Compared with the pristine PbTe, the lattice thermal conductivity values of pore-generated PbTe polycrystalline bulks were significantly reduced due to the enhanced phonon scattering by mismatched phonon modes in the presence of pores (200 nm–2 μm in the PbTe matrix. We obtained extremely low lattice thermal conductivity (~0.56 W m−1 K−1 at 773 K in pore-embedded PbTe bulk after sonication for the elimination of NaCl residue.

  14. Solid hydrocarbon assisted reduction: a new process of generating micron scale metal particles

    OpenAIRE

    Ryan M McCabe

    2015-01-01

    Approved for public release; distribution is unlimited The goal of this research is to test a central hypothesis: that gas species generated by the thermal and/or catalytically assisted decomposition of hydrocarbons in an inert atmosphere can reduce metal oxides to a metallic state. It is postulated that the decomposition releases gas phase radicals that can bind with oxygen in the metal oxides, forming volatile, stable oxides such as CO2 and water. This research consisted of thermally dec...

  15. Solar Pilot Plant, Phase I. Preliminary design report. Volume VI. Electrical power generation; master control subsystems; balance of plant CDRL item 2

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-05-01

    The Honeywell electrical power generation subsystem centers on a General Electric dual admission, triple extraction turbine generator sized to the output requirements of the Pilot Plant. The turbine receives steam from the receiver subsystem and/or the thermal storage subsystem and supplies those subsystems with feedwater. The turbine condensor is wet cooled. The plant control system consists of a coordinated digital master and subsystem digital/analog controls. The remainder of the plant, work spaces, maintenance areas, roads, and reception area are laid out to provide maximum convenience compatible with utility and safety. Most of the activities are housed in a complex around the base of the receiver tower. This volume contains a description of the relationship of the electrical power generation subsystem to the rest of the plant, the design methodology and evolution, the interface integration and control, and the operation and maintenance procedures.

  16. Decreasing ammonium generation using hydrogenotrophic bacteria in the process of nitrate reduction by nanoscale zero-valent iron

    Energy Technology Data Exchange (ETDEWEB)

    An, Yi; Li, Tielong [College of Environmental Science and Engineering/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/Ministry of Education Key Laboratory of Pollution Processed and Environmental Criteria, Nankai University, Tianjin 300071 (China); Jin, Zhaohui, E-mail: jinzh@nankai.edu.cn [College of Environmental Science and Engineering/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/Ministry of Education Key Laboratory of Pollution Processed and Environmental Criteria, Nankai University, Tianjin 300071 (China); Dong, Meiying; Li, Qianqian; Wang, Shuaima [College of Environmental Science and Engineering/Tianjin Key Laboratory of Environmental Remediation and Pollution Control/Ministry of Education Key Laboratory of Pollution Processed and Environmental Criteria, Nankai University, Tianjin 300071 (China)

    2009-10-15

    An integrated nitrate treatment using nanoscale zero-valent iron (NZVI) and Alcaligenes eutrophus, which is a kind of hydrogenotrophic denitrifying bacteria, was conducted to remove nitrate and decrease ammonium generation. Within 8 days, nitrate was removed completely in the reactors containing NZVI particles plus bacteria while the proportion of ammonium generated was only 33%. That is a lower reduction rate but a smaller proportion of ammonium relative to that in abiotic reactors. It was also found that ammonium generation experienced a biphasic process, involving an increasing period and a stable period. After domestication of the bacteria, the combined NZVI-cell system could remove all nitrate without ammonium released when the refreshed nitrate was introduced. Nitrate reduction and the final product distribution were also studied in batch reactors amended with different initial NZVI contents and biomass concentrations, respectively. Both the nitrate removal rate and the ammonium yield decreased when the initial content of NZVI reduced and the initial biomass concentration increased. However, about 27% of the nitrate was converted to ammonium when excess bacteria (OD{sub 422} = 0.026) were used, which was higher than that with appropriate amount of bacteria.

  17. Speckle noise reduction for computer generated holograms of objects with diffuse surfaces

    Science.gov (United States)

    Symeonidou, Athanasia; Blinder, David; Ahar, Ayyoub; Schretter, Colas; Munteanu, Adrian; Schelkens, Peter

    2016-04-01

    Digital holography is mainly used today for metrology and microscopic imaging and is emerging as an important potential technology for future holographic television. To generate the holographic content, computer-generated holography (CGH) techniques convert geometric descriptions of a 3D scene content. To model different surface types, an accurate model of light propagation has to be considered, including for example, specular and diffuse reflection. In previous work, we proposed a fast CGH method for point cloud data using multiple wavefront recording planes, look-up tables (LUTs) and occlusion processing. This work extends our method to account for diffuse reflections, enabling rendering of deep 3D scenes in high resolution with wide viewing angle support. This is achieved by modifying the spectral response of the light propagation kernels contained by the look-up tables. However, holograms encoding diffuse reflective surfaces depict significant amounts of speckle noise, a problem inherent to holography. Hence, techniques to improve the reduce speckle noise are evaluated in this paper. Moreover, we propose as well a technique to suppress the aperture diffraction during numerical, viewdependent rendering by apodizing the hologram. Results are compared visually and in terms of their respective computational efficiency. The experiments show that by modelling diffuse reflection in the LUTs, a more realistic yet computationally efficient framework for generating high-resolution CGH is achieved.

  18. Wind speed reductions by large-scale wind turbine deployments lower turbine efficiencies and set low generation limits.

    Science.gov (United States)

    Miller, Lee M; Kleidon, Axel

    2016-11-29

    Wind turbines generate electricity by removing kinetic energy from the atmosphere. Large numbers of wind turbines are likely to reduce wind speeds, which lowers estimates of electricity generation from what would be presumed from unaffected conditions. Here, we test how well wind power limits that account for this effect can be estimated without explicitly simulating atmospheric dynamics. We first use simulations with an atmospheric general circulation model (GCM) that explicitly simulates the effects of wind turbines to derive wind power limits (GCM estimate), and compare them to a simple approach derived from the climatological conditions without turbines [vertical kinetic energy (VKE) estimate]. On land, we find strong agreement between the VKE and GCM estimates with respect to electricity generation rates (0.32 and 0.37 We m(-2)) and wind speed reductions by 42 and 44%. Over ocean, the GCM estimate is about twice the VKE estimate (0.59 and 0.29 We m(-2)) and yet with comparable wind speed reductions (50 and 42%). We then show that this bias can be corrected by modifying the downward momentum flux to the surface. Thus, large-scale limits to wind power use can be derived from climatological conditions without explicitly simulating atmospheric dynamics. Consistent with the GCM simulations, the approach estimates that only comparatively few land areas are suitable to generate more than 1 We m(-2) of electricity and that larger deployment scales are likely to reduce the expected electricity generation rate of each turbine. We conclude that these atmospheric effects are relevant for planning the future expansion of wind power.

  19. Wet air oxidation pretreatment of biomethanated distillery effluent: mapping pretreatment efficiency in terms color, toxicity reduction and biogas generation.

    Science.gov (United States)

    Sarat Chandra, T; Malik, S N; Suvidha, G; Padmere, M L; Shanmugam, P; Mudliar, S N

    2014-04-01

    The effluents from molasses-based distilleries after biomethanation are beset with problems of intensified dark brown color, high residual COD, low biodegradability index (BOD/COD ratio Wet air oxidation (WAO) pretreatment of biomethanated distillery effluent resulted in substantial enhancement in the biodegradability index (BI) (up to 0.8). WAO pretreated effluent on anaerobic digestion indicated favorable biogas generation with methane content up to 64% along with concomitant COD reduction up to 54.75%. The HPLC analysis indicated that the pretreatment facilitated degradation of major color containing compounds-namely melanoidins, up to 97.8%. The pretreated effluent with enhanced biodegradability along with substantially reduced color also indicated positive effect on seed germination (up to 100%), implying toxicity reduction of the effluent post WAO pretreatment.

  20. Optimal Placement and Sizing of Distributed Generation And Capacitor Bank For Loss Reduction And Reliability Improvement In Distribution Systems

    Directory of Open Access Journals (Sweden)

    Reza Baghipourr

    2014-12-01

    Full Text Available In this paper optimum size and location of the capacitors and distributed generators (DGs are determined for reliability improvement and power loss reduction using genetic algorithm (GA. The main innovation of this paper is using both DG and Capacitor for the reliability improvement and power loss reduction. For this purpose an objective function consisting of reliability cost, power loss cost and also DG's and capacitor's investment cost are considered. The effectiveness of the proposed method is examined in the 10 and 33 bus test systems and comparative studies are conducted before and after DG and Capacitor installation in the test systems. The results obtained show the effectiveness of the proposed method.

  1. Reduction of ocean tide aliasing in the context of a next generation gravity field mission

    Science.gov (United States)

    Hauk, Markus; Daras, Ilias; Pail, Roland

    2017-04-01

    Ocean tide aliasing is currently one of the main limiting factors for temporal gravity field determination and the derivation of mass transport processes in the Earth system. This will be true even more for future gravity field missions with improved measurement technology, which cannot be fully exploited due to this dominant systematic error source. In several previous studies it has been shown that temporal aliasing, related to tidal and non-tidal sources, can be significantly reduced by double-pair formations, e.g., in a so-called Bender configuration, and its effects can be migrated to higher frequencies by an optimum orbit choice, especially the orbit altitude (Murböck et al. 2013). Improved processing strategies and extended parameter models should be able to further reduce the problem. Concerning non-tidal aliasing, it could be shown that the parameterization of short-period long-wavelength gravity field signals, the so-called Wiese approach, is a powerful method for aliasing reduction (Wiese et al. 2013), but it does not really work for the very short-period signals of ocean tides with mainly semi-diurnal and diurnal periods (Daras 2015). In this contribution, several methods dealing with the reduction of ocean tide aliasing are investigated both from a methodological and a numerical point of view. One of the promising strategies is the co-estimation of selected tidal constituents over long time periods, also considering the basic orbit frequencies of the satellites. These improved estimates for ocean tide signals can then be used in a second step as an enhanced de-aliasing product for the computation of short-period temporal gravity fields. From a number of theoretical considerations and numerical case-studies, recommendations for an optimum orbit selection with respect to reduction of ocean tide aliasing shall be derived for two main mission scenarios. The first one is a classical Bender configuration being composed of a (near-) polar and an inclined in

  2. Anesthesia-related changes in information transfer may be caused by reduction in local information generation.

    Science.gov (United States)

    Wollstadt, Patricia; Sellers, Kristin K; Hutt, Axel; Frohlich, Flavio; Wibral, Michael

    2015-08-01

    In anesthesia research it is an open question how general anesthetics lead to loss of consciousness (LOC). It has been proposed that LOC may be caused by the disruption of cortical information processing, preventing information integration. Therefore, recent studies investigating information processing under anesthesia focused on changes in information transfer, measured by transfer entropy (TE). However, often this complex technique was not applied rigorously, using time series in symbolic representation, or using TE differences without accounting for neural conduction delays, or without accounting for signal history. Here, we used current best-practice in TE estimation to investigate information transfer under anesthesia: We conducted simultaneous recordings in primary visual cortex (V1) and prefrontal cortex (PFC) of head-fixed ferrets in a dark environment under different levels of anesthesia (awake, 0.5% isoflurane, 1.0 % isoflurane). To elucidate reasons for changes in TE, we further quantified information processing within brain areas by estimating active information storage (AIS) as an estimator of predictable information, and Lempel-Ziv complexity (LZC) as an estimator of signal entropy. Under anesthesia, we found a reduction in information transfer (TE) between PFC and V1 with a stronger reduction for the feedback direction (PFC to V1), validating previous results. Furthermore, entropy (LZC) was reduced and activity became more predictable as indicated by higher values of AIS. We conclude that higher anesthesia concentrations indeed lead to reduced inter-areal information transfer, which may be partly caused by decreases in local entropy and increases in local predictability. In revealing a possible reason for reduced TE that is potentially independent of inter-areal coupling, we demonstrate the value of directly quantifying information processing in addition to focusing on dynamic properties such as coupling strength.

  3. Generation IV Nuclear Energy Systems Construction Cost Reductions through the use of Virtual Environments: Task 1 Completion Report

    Energy Technology Data Exchange (ETDEWEB)

    Whisker, V.E.; Baratta, A.J.; Shaw, T.S.; Winters, J.W.; Trikouros, N.; Hess, C.

    2002-11-26

    OAK B204 The objective of this project is to demonstrate the feasibility and effectiveness of using full-scale virtual reality simulation in the design, construction, and maintenance of future nuclear power plants. Specifically, this project will test the suitability of Immersive Projection Display (IPD) technology to aid engineers in the design of the next generation nuclear power plant and to evaluate potential cost reductions that can be realized by optimization of installation and construction sequences. The intent is to see if this type of information technology can be used in capacities similar to those currently filled by full-scale physical mockups.

  4. Uncertainty Reduction in Power Generation Forecast Using Coupled Wavelet-ARIMA

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Zhangshuan; Etingov, Pavel V.; Makarov, Yuri V.; Samaan, Nader A.

    2014-10-27

    In this paper, we introduce a new approach without implying normal distributions and stationarity of power generation forecast errors. In addition, it is desired to more accurately quantify the forecast uncertainty by reducing prediction intervals of forecasts. We use automatically coupled wavelet transform and autoregressive integrated moving-average (ARIMA) forecasting to reflect multi-scale variability of forecast errors. The proposed analysis reveals slow-changing “quasi-deterministic” components of forecast errors. This helps improve forecasts produced by other means, e.g., using weather-based models, and reduce forecast errors prediction intervals.

  5. NOx reduction using amine reclaimer wastes (ARW) generated in post combustion CO2 capture

    DEFF Research Database (Denmark)

    Botheju, Deshai; Glarborg, Peter; Tokheim, Lars-Andre

    2012-01-01

    Amine reclaimer wastes (ARW) generated in CO2 capture processes demand suitable disposal means. Such wastes contain remaining amine, NH3 and other degradation compounds. This study investigated the potential of using ARW as a NOx reducing agent, under laboratory conditions in a flow reactor....... A simulated flue gas containing about 500 ppm of NO and 5% O2 was injected with liquid ARW under different stoichiometric ratios (TN/NO – total N to nitric oxide ratio) and temperatures. The ARW was obtained from a distillation monoethanolamine reclaimer in an industrial CO2 capture facility with a coal fired...

  6. Achieving 60% CO{sub 2} reductions within the UK energy system-Implications for the electricity generation sector

    Energy Technology Data Exchange (ETDEWEB)

    Odenberger, M. [Energy Conversion, Department of Energy and Environment, Chalmers University of Technology, SE 412 96 Goeteborg (Sweden); Johnsson, F. [Energy Conversion, Department of Energy and Environment, Chalmers University of Technology, SE 412 96 Goeteborg (Sweden)]. E-mail: filip.johnsson@me.chalmers.se

    2007-04-15

    This paper explores how investment in the UK electricity generation sector can contribute to the UK goal of reducing CO{sub 2} emissions with 60% by the year 2050 relative to the 1990 emissions. Considering likely development of the transportation sector and industry over the period, i.e. a continued demand growth and dependency on fossil fuels and electricity, the analysis shows that this implies CO{sub 2} emission reductions of up to 90% by 2050 for the electricity sector. Emphasis is put on limitations imposed by the present system, described by a detailed database of existing power plants, together with meeting targets on renewable electricity generation (RES) including assumptions on gas acting as backup technology for intermittent RES. In particular, it is investigated to what extent new fossil fuelled and nuclear power is required to meet the year 2050 demand as specified by the Royal Commission on Environmental Pollution (RCEP). In addition, the number of sites required for centralized electricity generation (large power plants) is compared with the present number of sites. A simulation model was developed for the analysis. The model applies the UK national targets on RES, taken from Renewable Obligation (RO) for 2010 and 2020 and potentials given by RCEP for 2050, and assumed technical lifetimes of the power plants of the existing system and thus, links this system with targets for the years 2010, 2020 and 2050. The results illustrate the problem with lock-in effects due to long capital stock turnover times, which can either lead to political difficulty meeting targets in established policy or costly early retirement of power plants (stranded assets) to comply with emission goals prescribed in Kyoto targets or the 60% emission reduction goal. Assuming typical technical lifetimes of the power plants it can be concluded that the present electricity generation system continues to play a significant role for several decades generating about 50% of projected

  7. Achieving 60% CO{sub 2} reductions within the UK energy system - implications for the electricity generation sector

    Energy Technology Data Exchange (ETDEWEB)

    Odenberger, M.; Johnsson, F. [Chalmers University of Technology, Goeteborg (Sweden). Dept. of Energy and Environment

    2007-04-15

    This paper explores how investment in the UK electricity generation sector can contribute to the UK goal of reducing CO{sub 2} emissions with 60% by the year 2050 relative to the 1990 emissions. Considering likely development of the transportation sector and industry over the period, i.e. a continued demand growth and dependency on fossil fuels and electricity, the analysis shows that this implies CO{sub 2} emission reductions of up to 90% by 2050 for the electricity sector. Emphasis is put on limitations imposed by the present system, described by a detailed database of existing power plants, together with meeting targets on renewable electricity generation (RES) including assumptions on gas acting as backup technology for intermittent RES. In particular, it is investigated to what extent new fossil fuelled and nuclear power is required to meet the year 2050 demand as specified by the Royal Commission on Environmental Pollution (RCEP). In addition, the number of sites required for centralized electricity generation (large power plants) is compared with the present number of sites. A simulation model was developed for the analysis. The model applies the UK national targets on RES, taken from Renewable Obligation (RO) for 2010 and 2020 and potentials given by RCEP for 2050, and assumed technical lifetimes of the power plants of the existing system and thus, links this system with targets for the years 2010, 2020 and 2050. The results illustrate the problem with lock-in effects due to long capital stock turnover times, which can either lead to political difficulty meeting targets in established policy or costly early retirement of power plants (stranded assets) to comply with emission goals prescribed in Kyoto targets or the 60% emission reduction goal. Assuming typical technical lifetimes of the power plants it can be concluded that the present electricity generation system continues to play a significant role for several decades generating about 50% of projected

  8. Oxidation of diesel-generated volatile organic compounds in the selective catalytic reduction process

    Energy Technology Data Exchange (ETDEWEB)

    Koebel, M.; Elsener, M. [Paul Scherrer Inst., Villigen (Switzerland). Combustion Research

    1998-10-01

    The main part of the VOCs (volatile organic compounds) contained in diesel exhaust ({approx}80%) is oxidized to CO and CO{sub 2} over an SCR (selective catalytic reduction) catalyst. CO is the major product of this oxidation, representing about 50--70% of the formed products (CO + CO{sub 2}). This preferential formation of CO leads to a pronounced increase of CO emissions when an SCR process is added to a diesel engine. A small fraction of the VOCs is selectively oxidized to carboxylic acids over the SCR catalyst. This selectivity is due to the acidic properties of the catalyst causing the preferential desorption at the oxidation state of the acid. The main products of these oxidation reactions are the lower monocarboxylic acids and some dicarboxylic acids forming stable anhydrides, especially maleic and phthalic acid. The highest emissions of these acids are found at low temperatures; they decrease at higher temperatures. Formic acid is preferentially decomposed into carbon monoxide and water. It must therefore be assumed that the strong increase of CO mentioned above is due to a mechanism involving the thermal decomposition of formic acid formed from various primary VOCs.

  9. Item analysis and screening of second-generation sub-health questionnaire%第2代亚健康调查表的项目分析与筛选

    Institute of Scientific and Technical Information of China (English)

    陈晶; 赵晓山; 魏敏; 孙晓敏; 戴红芳; 李纪强; 罗仁

    2009-01-01

    目的:结合多种项目分析方法对第2代亚健康调查表各个条目进行分析与筛选,为进一步研制亚健康量表奠定基础.方法:调查分析于2006-12/2008-05在南方医科大学完成.按整群抽样法抽取广州市某医科大学在读大学生共6 000名.采用现场问卷调查的方式,内容包括躯体症状、心理症状和社会症状和生存质量的总评.发出问卷6 000份,收同有效问卷5 599份.采用离散程度法、相关系数法、因子分析法、区分度分析法及克朗巴赫α系数法等5种方法对83个条目进行分析.结果:汇总5种方法的提名,将每一个条目选出被提名次数达4次以上者作为最终结果,共有63个条目最终被入选.结论:筛选出的63个条目均具备有较好的敏感性、代表性、独立性、重要性及内部一致性,为下一步研制亚健康量表提供基础.%OBJECTIVE: To screen and analyze items of the second-generation sub-health questionnaire through various item analysis methods, so as to provide basic data for the further study of sub-health measuring scale. METHODS: The investigation and analysis was completed in Southem Medical University between November 2006 and May 2008. A total of 6 000 college students were selected as the investigation targets with cluster sampling method from a medical university in Guangzhou. 6 000 questionnaires were assigned to them in which the answerer was asked about their somatic symptoms, psychological symptoms and social symptoms, with 5 599 valid ones obtained. Eighty three items were analyzed through five methods based on dispersion, correlation coefficient, factor analysis, t-test and Cronbach's g. RESULTS: At last, 63 items were selected to constitute the item pool of the sub-health scale, which were nominated over 4 times according to the nomination summary of the 5 methods.CONCLUSION: All the 63 items kept in the second-generation sub-health questionnaire feature satisfactory sensibility

  10. Optimal Allocation of Distributed Generation and Capacitor Banks in Order to Loss Reduction in Reconfigured System

    Directory of Open Access Journals (Sweden)

    Noradin Ghadimi

    2012-01-01

    Full Text Available The concern about the limitation of fossil fuels and also rising consciousness of environmental protection, cause the installation of DGs increase annually. This study develops an optimal placement method in order to sizing and sitting of distributed generation and capacitor banks in IEEE 33 bus test system that reconfigured. The algorithm for optimization in this paper is simulated annealing. The proposed objective function considers active power losses of the system and the voltage profile in nominal load of system. High performance of the proposed algorithm in mention system is verified by simulations in MATLAB software and in order to illustrate of feasibility of proposed method this optimization will accomplish in two cases.

  11. Reduction of Error in Handoff Initiation Time Calculation for Next-Generation Wireless Systems

    Directory of Open Access Journals (Sweden)

    Debabrata Sarddar

    2010-09-01

    Full Text Available Recent research in wireless communications technologies has focused to the development of Next-generation wireless systems (NGWS which integrate various existing wireless networks technologies, each of which is optimized for some specific services such as WLANs, WiMAX, General Packet Radio Service (GPRS and Universal Mobile Telecommunications System (UMTS. The most important and challenging issue is to realize seamless handoffs with small handoff latency and packet loss to ensure the Quality of Service (QoS in NGWS. In this paper, we propose a handoff management architecture using relative signal strength of the present and neighboring base stations to calculate the handoff initiation time. To take the right decision of handoff initiation time we use mobile’s speed, handoff signaling delayinformation and also the size of the present and neighboring celland reduce the errors associated with them. The performance analysis shows that the approach ensures successful handoff and reduces call blocking probability.

  12. Laser speckle reduction by phase range limited computer generated hologram in laser projection display system.

    Science.gov (United States)

    Chang, Yan-Shuo; Lin, Chia-Hsin; Hsu, Ku-Hui; Hsu, Wei-Feng; Hsiao, Li-Jen; Lin, Hoang Yan

    2014-09-20

    The speckle phenomenon is an annoyance in laser projection display systems. We propose a novel speckle suppression method that utilizes the interference concept on a pixel point, which reduces the speckle contrast (SC) of the project image by limiting the phase distribution range in the optical field. The SC formula is derived in the uniform interval phase range for partially developed speckle conditions, showing that the SC can be lowered by lessening the phase range limitation. In the ideal simulation model, the SC can be reduced from 98.77% to 0% as the phase range limitation varies from 2π to 0. The phase range limitation model is a novel method using a computer generated hologram to provide beam shaping and phase limitation. In a more realistic simulation model, the SC is reduced from 99.18% to 16.68%.

  13. Writing better test items.

    Science.gov (United States)

    Aucoin, Julia W

    2005-01-01

    Professional development specialists have had little opportunity to learn how to write test items to meet the expectations of today's graduate nurse. Schools of nursing have moved away from knowledge-level test items and have had to develop more application and analysis items to prepare graduates for the National Council Licensure Examination (NCLEX). This same type of question can be used effectively to support a competence assessment system and document critical thinking skills.

  14. Fuel Savings and Emission Reductions from Next-Generation Mobile Air Conditioning Technology in India

    Energy Technology Data Exchange (ETDEWEB)

    Chaney, L.; Thundiyil, K.; Andersen, S.; Chidambaram, S.; Abbi, Y. P.

    2007-01-01

    Up to 19.4% of vehicle fuel consumption in India is devoted to air conditioning (A/C). Indian A/C fuel consumption is almost four times the fuel penalty in the United States and close to six times that in the European Union because India's temperature and humidity are higher and because road congestion forces vehicles to operate inefficiently. Car A/C efficiency in India is an issue worthy of national attention considering the rate of increase of A/C penetration into the new car market, India's hot climatic conditions and high fuel costs. Car A/C systems originally posed an ozone layer depletion concern. Now that industrialized and many developing countries have moved away from ozone-depleting substances per Montreal Protocol obligations, car A/C impact on climate has captured the attention of policy makers and corporate leaders. Car A/C systems have a climate impact from potent global warming potential gas emissions and from fuel used to power the car A/Cs. This paper focuses on car A/C fuel consumption in the context of the rapidly expanding Indian car market and how new technological improvements can result in significant fuel savings and consequently, emission reductions. A 19.4% fuel penalty is associated with A/C use in the typical Indian passenger car. Car A/C fuel use and associated tailpipe emissions are strong functions of vehicle design, vehicle use, and climate conditions. Several techniques: reducing thermal load, improving vehicle design, improving occupants thermal comfort design, improving equipment, educating consumers on impacts of driver behaviour on MAC fuel use, and others - can lead to reduced A/C fuel consumption.

  15. Reduction of chalcogen oxyanions and generation of nanoprecipitates by the photosynthetic bacterium Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Borghese, Roberto, E-mail: roberto.borghese@unibo.it [Department of Pharmacy and Biotechnology, University of Bologna (Italy); Baccolini, Chiara; Francia, Francesco [Department of Pharmacy and Biotechnology, University of Bologna (Italy); Sabatino, Piera [Department of Chemistry G. Ciamician, University of Bologna (Italy); Turner, Raymond J. [Department of Biological Sciences, University of Calgary, Calgary, Alberta (Canada); Zannoni, Davide, E-mail: davide.zannoni@unibo.it [Department of Pharmacy and Biotechnology, University of Bologna (Italy)

    2014-03-01

    Graphical abstract: - Highlights: • R. capsulatus cells produce extracellular chalcogens nanoprecipitates when lawsone is present. • Lawsone acts as a redox mediator from reducing equivalents to tellurite and selenite. • Nanoprecipitates production depends on carbon source and requires metabolically active cells. • Te{sup 0} and Se{sup 0} nanoprecipitates are identified by X-ray diffraction (XRD) spectroscopy. - Abstract: The facultative photosynthetic bacterium Rhodobacter capsulatus is characterized in its interaction with the toxic oxyanions tellurite (Te{sup IV}) and selenite (Se{sup IV}) by a highly variable level of resistance that is dependent on the growth mode making this bacterium an ideal organism for the study of the microbial interaction with chalcogens. As we have reported in the past, while the oxyanion tellurite is taken up by R. capsulatus cells via acetate permease and it is reduced to Te{sup 0} in the cytoplasm in the form of splinter-like black intracellular deposits no clear mechanism was described for Se{sup 0} precipitation. Here, we present the first report on the biotransformation of tellurium and selenium oxyanions into extracellular Te{sup 0} and Se{sup 0}nanoprecipitates (NPs) by anaerobic photosynthetically growing cultures of R. capsulatus as a function of exogenously added redox-mediator lawsone, i.e. 2-hydroxy-1,4-naphthoquinone. The NPs formation was dependent on the carbon source used for the bacterial growth and the rate of chalcogen reduction was constant at different lawsone concentrations, in line with a catalytic role for the redox mediator. X-ray diffraction (XRD) analysis demonstrated the Te{sup 0} and Se{sup 0} nature of the nanoparticles.

  16. Superoxide generated from the glutathione-mediated reduction of selenite damages the iron-sulfur cluster of chloroplastic ferredoxin.

    Science.gov (United States)

    Fisher, Brian; Yarmolinsky, Dmitry; Abdel-Ghany, Salah; Pilon, Marinus; Pilon-Smits, Elizabeth A; Sagi, Moshe; Van Hoewyk, Doug

    2016-09-01

    Selenium assimilation in plants is facilitated by several enzymes that participate in the transport and assimilation of sulfate. Manipulation of genes that function in sulfur metabolism dramatically affects selenium toxicity and accumulation. However, it has been proposed that selenite is not reduced by sulfite reductase. Instead, selenite can be non-enzymatically reduced by glutathione, generating selenodiglutathione and superoxide. The damaging effects of superoxide on iron-sulfur clusters in cytosolic and mitochondrial proteins are well known. However, it is unknown if superoxide damages chloroplastic iron-sulfur proteins. The goals of this study were twofold: to determine whether decreased activity of sulfite reductase impacts selenium tolerance in Arabidopsis, and to determine if superoxide generated from the glutathione-mediated reduction of selenite damages the iron-sulfur cluster of ferredoxin. Our data demonstrate that knockdown of sulfite reductase in Arabidopsis does not affect selenite tolerance or selenium accumulation. Additionally, we provide in vitro evidence that the non-enzymatic reduction of selenite damages the iron-sulfur cluster of ferredoxin, a plastidial protein that is an essential component of the photosynthetic light reactions. Damage to ferredoxin's iron-sulfur cluster was associated with formation of apo-ferredoxin and impaired activity. We conclude that if superoxide damages iron-sulfur clusters of ferredoxin in planta, then it might contribute to photosynthetic impairment often associated with abiotic stress, including toxic levels of selenium.

  17. Bulk Volume Reduction of the Kimmeridge Clay Formation, North Sea (UK Due to Compaction, Petroleum Generation and Expulsion

    Directory of Open Access Journals (Sweden)

    Kenneth S. Okiongbo

    2011-02-01

    Full Text Available In this study, the effects of petroleum generation and expulsion on shale porosity is explored by evaluating the compaction of the Kimmeridge Clay Formation (KCF within the oil window using log data and shale samples from the KCF within the depth and temperature range of ~1.5-5.0 km and 90-157ºC, respectively. Petrophysical properties e.g porosity and pore-size distribution were measured, and permeability was calculated using empirical models based on the measured porosities. Transit-time values from the sonic logs recorded at depths in the wells were the cores were recovered were calibrated against the porosities determined from the core samples. Bulk geochemical parameters e.g., Total Organic Carbon (TOC, Hydrogen Index (HI were determined. The volume reduction in the KCF within the oil window due to petroleum generation and expulsion, and compaction due to loss of pore space was determined using the geochemical and log derived porosity data emplaced into empirical relations. Porosities above the oil window range from ~15-20%, but decreased to <5% at the end of the oil window. Pore-sizes decrease from ~11 nm to between 6-8 nm at the depth range of 1.5-5.0 km. Permeability decreased from 4.8 nD to ~0.095 nD. The quantitative estimations of volume reduction within the oil window indicate that for ~8.0wt% initial TOC sediment, a bulk volume reduction of 13% of the initial volume is due to oil expulsion, and ~12% is due to loss of pore space.

  18. Electron transfer capacity dependence of quinone-mediated Fe(III) reduction and current generation by Klebsiella pneumoniae L17.

    Science.gov (United States)

    Li, Xiaomin; Liu, Liang; Liu, Tongxu; Yuan, Tian; Zhang, Wei; Li, Fangbai; Zhou, Shungui; Li, Yongtao

    2013-06-01

    Quinone groups in exogenous electron shuttles can accelerate extracellular electron transfer (EET) from bacteria to insoluble terminal electron acceptors, such as Fe(III) oxides and electrodes, which are important in biogeochemical redox processes and microbial electricity generation. However, the relationship between quinone-mediated EET performance and electron-shuttling properties of the quinones remains incompletely characterized. This study investigates the effects of a series of synthetic quinones (SQs) on goethite reduction and current generation by a fermenting bacterium Klebsiella pneumoniae L17. In addition, the voltammetric behavior and electron transfer capacities (ETCs) of SQ, including electron accepting (EAC) and donating (EDC) capacities, is also examined using electrochemical methods. The results showed that SQ can significantly increase both the Fe(III) reduction rates and current outputs of L17. Each tested SQ reversibly accepted and donated electrons as indicated by the cyclic voltammograms. The EAC and EDC results showed that Carmine and Alizarin had low relative capacities of electron transfer, whereas 9,10-anthraquinone-2,6-disulfonic acid (AQDS), 2-hydroxy-1,4-naphthoquinone (2-HNQ), and 5-hydroxy-1,4-naphthoquinone (5-HNQ) showed stronger relative ETC, and 9,10-anthraquinone-2-carboxylic acid (AQC) and 9,10-anthraquinone-2-sulfonic acid (AQS) had high relative ETC. Enhancement of microbial goethite reduction kinetics and current outputs by SQ had a good linear relationship with their ETC, indicating that the effectiveness of quinone-mediated EET may be strongly dependent on the ETC of the quinones. Therefore, the presence of quinone compounds and fermenting microorganisms may increase the diversity of microbial populations that contribute to element transformation in natural environments. Moreover, ETC determination of different SQ would help to evaluate their performance for microbial EET under anoxic conditions. Copyright © 2013 Elsevier

  19. Combustion efficiency: Greenhouse gas emission reductions from the power generation sector

    Energy Technology Data Exchange (ETDEWEB)

    Kane, R.; South, D.W.; Fish, A.L. [Argonne National Laboratory, Upton, IL (United States)

    1993-12-31

    Concern for the possibility of an enhanced greenhouse effect and global climate change (GCC) has often been associated with energy use in general, and fossil fuel combustion in particular, because of associated emissions of CO{sub 2} and other greenhouse gases (GHG). Therefore, energy policies play a significant role in determining greenhouse gas emissions. The generation of electricity and power from more efficient fossil energy technologies provides an opportunity to significantly lower GHG emissions, together with other pollutants. The U.S. government oversees a broad-based program to facilitate the development, demonstration, and deployment of these technologies. Advanced fossil technologies offer other benefits as well, in that they permit continued use of widely available fuels such as coal. An international perspective is critical for assessing the role of these fuels, since countries differ in terms of their ability to maximize these benefits. Often, new technologies are considered the domain of industrialized countries. Yet more efficient technologies may have their greatest potential - to concurrently permit the utilization of indigenous fuels and to lower global GHG emissions in developing countries, especially those in the Asia-Pacific region.

  20. Analysis of the Effect of Module Thickness Reduction on Thermoelectric Generator Output

    Science.gov (United States)

    Brito, F. P.; Figueiredo, L.; Rocha, L. A.; Cruz, A. P.; Goncalves, L. M.; Martins, J.; Hall, M. J.

    2016-03-01

    Conventional thermoelectric generators (TEGs) used in applications such as exhaust heat recovery are typically limited in terms of power density due to their low efficiency. Additionally, they are generally costly due to the bulk use of rare-earth elements such as tellurium. If less material could be used for the same output, then the power density and the overall cost per kilowatt (kW) of electricity produced could drop significantly, making TEGs a more attractive solution for energy harvesting of waste heat. The present work assesses the effect of reducing the amount of thermoelectric (TE) material used (namely by reducing the module thickness) on the electrical output of conventional bismuth telluride TEGs. Commercial simulation packages (ANSYS CFX and thermal-electric) and bespoke models were used to simulate the TEGs at various degrees of detail. Effects such as variation of the thermal and electrical contact resistance and the component thickness and the effect of using an element supporting matrix (e.g., eggcrate) instead of having air conduction in void areas have been assessed. It was found that indeed it is possible to reduce the use of bulk TE material while retaining power output levels equivalent to thicker modules. However, effects such as thermal contact resistance were found to become increasingly important as the active TE material thickness was decreased.

  1. Renewable energies for reduction of greenhouse gases in the Mexican electricity generation in 2025

    Energy Technology Data Exchange (ETDEWEB)

    Islas, J; Manzini, F; Martinez, M [Centre for Energy Research, UNAM, Temixco, Morelos (Mexico)

    2000-07-01

    This study presents three scenarios relating to the environmental futures of electricity generation in Mexico up to the year 2025. The first scenario emphasizes the use of oil products, particularly fuel oil, and represents the energy policy path that was in effect until 1990. The second scenario prioritizes the use of natural gas, reflecting the energy consumption pattern that arose in the mid-90's as a result of reforms in the energy sector. In the third scenario, the high participation of renewable sources of energy is considered feasible from a technical and economic point of view. The three scenarios are evaluated up to the year 2025 in terms of greenhouse gases (GHG) and acid rain precursor gases (ARPG). [Spanish] Este estudio presenta tres escenarios relacionados de los futuros ambientales de generacion de electricidad en Mexico hasta el ano 2025. El primer escenario enfatiza la utilizacion de productos del petroleo, particularmente el combustoleo, y representa el curso de la politica de energia vigente hasta 1990. El segundo escenario da prioridad al uso de gas natural, reflejando el patron de consumo de energia que surgio a mediados de los 90's como resultado de reformas en el sector energetico. En el tercer escenario, la alta participacion de las fuentes renovables de energia es considerada factible desde los puntos de vista tecnico y economico. Los tres escenarios son evaluados hasta el ano 2025 en terminos de los gases de efecto invernadero (GHG) y de gases precursores de lluvia acida (ARPG).

  2. Ag nanoparticles generated using bio-reduction and -coating cause microbial killing without cell lysis.

    Science.gov (United States)

    Gade, Aniket; Adams, Joshua; Britt, David W; Shen, Fen-Ann; McLean, Joan E; Jacobson, Astrid; Kim, Young-Cheol; Anderson, Anne J

    2016-04-01

    Cost-effective "green" methods of producing Ag nanoparticles (NPs) are being examined because of the potential of these NPs as antimicrobials. Ag NPs were generated from Ag ions using extracellular metabolites from a soil-borne Pythium species. The NPs were variable in size, but had one dimension less than 50 nm and were biocoated; aggregation and coating changed with acetone precipitation. They had dose-dependent lethal effects on a soil pseudomonad, Pseudomonas chlororaphis O6, and were about 30-fold more effective than Ag(+) ions. A role of reactive oxygen species in cell death was demonstrated by use of fluorescent dyes responsive to superoxide anion and peroxide accumulation. Also mutants of the pseudomonad, defective in enzymes that protect against oxidative stress, were more sensitive than the wild type strain; mutant sensitivity differed between exposure to Ag NPs and Ag(+) ions demonstrating a nano-effect. Imaging of bacterial cells treated with the biocoated Ag NPs revealed no cell lysis, but there were changes in surface properties and cell height. These findings support that biocoating the NPs results in limited Ag release and yet they retained potent antimicrobial activity.

  3. Biomass waste gasification - can be the two stage process suitable for tar reduction and power generation?

    Science.gov (United States)

    Sulc, Jindřich; Stojdl, Jiří; Richter, Miroslav; Popelka, Jan; Svoboda, Karel; Smetana, Jiří; Vacek, Jiří; Skoblja, Siarhei; Buryan, Petr

    2012-04-01

    A pilot scale gasification unit with novel co-current, updraft arrangement in the first stage and counter-current downdraft in the second stage was developed and exploited for studying effects of two stage gasification in comparison with one stage gasification of biomass (wood pellets) on fuel gas composition and attainable gas purity. Significant producer gas parameters (gas composition, heating value, content of tar compounds, content of inorganic gas impurities) were compared for the two stage and the one stage method of the gasification arrangement with only the upward moving bed (co-current updraft). The main novel features of the gasifier conception include grate-less reactor, upward moving bed of biomass particles (e.g. pellets) by means of a screw elevator with changeable rotational speed and gradual expanding diameter of the cylindrical reactor in the part above the upper end of the screw. The gasifier concept and arrangement are considered convenient for thermal power range 100-350 kW(th). The second stage of the gasifier served mainly for tar compounds destruction/reforming by increased temperature (around 950°C) and for gasification reaction of the fuel gas with char. The second stage used additional combustion of the fuel gas by preheated secondary air for attaining higher temperature and faster gasification of the remaining char from the first stage. The measurements of gas composition and tar compound contents confirmed superiority of the two stage gasification system, drastic decrease of aromatic compounds with two and higher number of benzene rings by 1-2 orders. On the other hand the two stage gasification (with overall ER=0.71) led to substantial reduction of gas heating value (LHV=3.15 MJ/Nm(3)), elevation of gas volume and increase of nitrogen content in fuel gas. The increased temperature (>950°C) at the entrance to the char bed caused also substantial decrease of ammonia content in fuel gas. The char with higher content of ash leaving the

  4. Fuel and Greenhouse Gas Emission Reduction Potentials by Appropriate Fuel Switching and Technology Improvement in the Canadian Electricity Generation Sector

    Directory of Open Access Journals (Sweden)

    Farshid Zabihian

    2010-01-01

    Full Text Available Problem statement: In recent years, Greenhouse Gas (GHG emissions and their potential effects on global climate change have been a worldwide concern. According to International Energy Agency (IEA, power generation contributes more than half of the global GHG emissions. Approach: Purpose of this study is to examine GHG emission reduction potentials in the Canadian electricity generation sector through fuel switching and adoption of advanced power generation systems. To achieve this objective, eight different scenarios were introduced. In the first scenario, existing power stations’ fuel was switched to natural gas. Existing power plants were replaced by Natural Gas Combined Cycle (NGCC, Integrated Gasification Combined Cycle (IGCC, Solid Oxide Fuel Cell (SOFC, hybrid SOFC and SOFC-IGCC hybrid power stations in scenario numbers 2 to 6, respectively. In last two scenarios, CO2 capture systems were installed in the existing power plants and in the second scenario, respectively. Results: The results showed that Canada’s GHG emissions can be reduced by 33, 59, 20, 64, 69, 29, 86 and 94% based on the first to eighth scenarios, respectively. On the other hand, the second scenario is the most practical and its technology has already matured and is available. In this scenario by replacing existing power plants by NGCC power plants, Canada can fulfill more than 25% of its 238,000 kt year-1 commitment of GHG emission reduction to the Kyoto Protocol. In addition, the GHG emission reduction potentials for each province and Canada as a whole were presented and compared. Based on the results, Alberta, Ontario and Saskatchewan are the biggest producers of GHG in Canada by emitting 49, 21 and 14% of Canada’s GHG emissions, respectively. Therefore, they have higher potential to reduce GHG emissions. The comparison of the results for different provinces revealed that based on efficiency of electricity generation and consumed fuel distribution; specific scenario

  5. Associations between appearance-related self-discrepancies and young women's and men's affect, body satisfaction, and emotional eating: a comparison of fixed-item and participant-generated self-discrepancies.

    Science.gov (United States)

    Halliwell, Emma; Dittmar, Helga

    2006-04-01

    This study examines the associations between appearance-related, actual-ideal self-discrepancies--from both own and romantic partner's standpoints--and negative affect, body satisfaction, and eating behavior. It extends previous research through studying both genders and the romantic partner standpoint, but its main novel contribution is a systematic comparison between idiographic, participant-generated, and nomothetic, fixed-item measures of appearance-related self-discrepancies. The findings show that these measures cannot be, and should not be, treated as equivalent. The idiographic measures were superior in predicting outcome variables when considering the own standpoint. Nomothetic measures did demonstrate some gender-specific associations, but only from the romantic partner standpoint, and only for women. These findings can be explained with respect to the assessment of accessible, versus available, self-discrepancies. Implications for self-discrepancy and body image theory and research are discussed.

  6. Distributed generation and their remuneration in the reduction of losses; Geracao distribuida e sua remuneracao na reducao de perdas

    Energy Technology Data Exchange (ETDEWEB)

    Chaves, Francisco David Moya; Jannuzzi, Gilberto de Martino [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica; Silva, Luiz Carlos Pereira da [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Eletrica e de Computacao

    2008-07-01

    The problematic associated to the Distribution Generation (DG) impact has several implications (economic, technical and environmental). The DG can to influence positive (reduction) or negatively (increase) about the level of losses. The impacts caused by the use of DG influence directly on the economic incentives that can get the DG. This paper presents some of the benefits and technical limitations in the use of DG in the provision of active and reactive power for each of the levels of transmission, sub transmission and distribution. An economic review where there is a decrease in the total cost of production of electric energy by the use of DG is shown. This reducing costs, can be used as an additional remuneration for the DG or used also in new investment in the expansion of DG without overlooking that within these technologies, deals are the Renewable Energy Sources. (author)

  7. Assessing "dangerous climate change": required reduction of carbon emissions to protect young people, future generations and nature.

    Directory of Open Access Journals (Sweden)

    James Hansen

    Full Text Available We assess climate impacts of global warming using ongoing observations and paleoclimate data. We use Earth's measured energy imbalance, paleoclimate data, and simple representations of the global carbon cycle and temperature to define emission reductions needed to stabilize climate and avoid potentially disastrous impacts on today's young people, future generations, and nature. A cumulative industrial-era limit of ∼500 GtC fossil fuel emissions and 100 GtC storage in the biosphere and soil would keep climate close to the Holocene range to which humanity and other species are adapted. Cumulative emissions of ∼1000 GtC, sometimes associated with 2°C global warming, would spur "slow" feedbacks and eventual warming of 3-4°C with disastrous consequences. Rapid emissions reduction is required to restore Earth's energy balance and avoid ocean heat uptake that would practically guarantee irreversible effects. Continuation of high fossil fuel emissions, given current knowledge of the consequences, would be an act of extraordinary witting intergenerational injustice. Responsible policymaking requires a rising price on carbon emissions that would preclude emissions from most remaining coal and unconventional fossil fuels and phase down emissions from conventional fossil fuels.

  8. Assessing 'Dangerous Climate Change': Required Reduction of Carbon Emissions to Protect Young People, Future Generations and Nature

    Science.gov (United States)

    Hansen, James; Kharecha, Pushker; Sato, Makiko; Masson-Demotte, Valerie; Ackerman, Frank; Beerling, David J.; Hearty, Paul J.; Hoegh-Guldberg, Ove; Hsu, Shi-Ling; Parmesan, Camille; hide

    2013-01-01

    We assess climate impacts of global warming using ongoing observations and paleoclimate data. We use Earth's measured energy imbalance, paleoclimate data, and simple representations of the global carbon cycle and temperature to define emission reductions needed to stabilize climate and avoid potentially disastrous impacts on today's young people, future generations, and nature. A cumulative industrial-era limit of approx.500 GtC fossil fuel emissions and 100 GtC storage in the biosphere and soil would keep climate close to the Holocene range to which humanity and other species are adapted. Cumulative emissions of approx.1000 GtC, sometimes associated with 2 C global warming, would spur "slow" feedbacks and eventual warming of 3-4 C with disastrous consequences. Rapid emissions reduction is required to restore Earth's energy balance and avoid ocean heat uptake that would practically guarantee irreversible effects. Continuation of high fossil fuel emissions, given current knowledge of the consequences, would be an act of extraordinary witting intergenerational injustice. Responsible policymaking requires a rising price on carbon emissions that would preclude emissions from most remaining coal and unconventional fossil fuels and phase down emissions from conventional fossil fuels.

  9. Oxygen reduction activity of carbon fibers cathode, and application for current generation from the NAD+ and NADH recycling reaction

    Directory of Open Access Journals (Sweden)

    H. Maeda

    2012-03-01

    Full Text Available Carbon fibers treated at 700 oC for 10 min were found to have O2 reduction activity when being used as a cathode. The special type of partition combined with both cationic and anionic exchange membranes was applied between anode cell and cathode cell in order to use a highly acidic solution such as 0.5 M H2SO4 as an electrolyte of the cathode cell for increasing the efficiency of O2 reduction activity. The current generation from NAD+ and NADH recycling system combined with D-gluconolactone production from 500 mg of D-glucose was performed by applying only carbon fibers for both anode and cathode. The total current volume obtained was 81.4 mAh during the reaction for 10 h, and the current efficiency was 93%. One gram of carbon fibers was pressed with Nafion paste on a piece of carbon paper(area : 50 mm×50mm with heating to prepare the cathode, and this construct was combined with conventional fuel cell. The power density was 3.6 mW/cm2, and the total power volume was calculated to be 90 mW per 1 g of carbon fibers.

  10. Modeling Local Item Dependence in Cloze and Reading Comprehension Test Items Using Testlet Response Theory

    Science.gov (United States)

    Baghaei, Purya; Ravand, Hamdollah

    2016-01-01

    In this study the magnitudes of local dependence generated by cloze test items and reading comprehension items were compared and their impact on parameter estimates and test precision was investigated. An advanced English as a foreign language reading comprehension test containing three reading passages and a cloze test was analyzed with a…

  11. Mitomycin C-DNA adducts generated by DT-diaphorase. Revised mechanism of the enzymatic reductive activation of mitomycin C.

    Science.gov (United States)

    Suresh Kumar, G; Lipman, R; Cummings, J; Tomasz, M

    1997-11-18

    Mitomycin C (MC) was reductively activated by DT-diaphorase [DTD; NAD(P)H:quinone oxidoreductase] from rat liver carcinoma cells in the presence of Micrococcus lysodeicticus DNA at pH 5.8 and 7.4. The resulting alkylated MC-DNA complexes were digested to the nucleoside level and the covalent MC-nucleoside adducts were separated, identified, and quantitatively analyzed by HPLC. In analogous experiments, two other flavoreductases, NADH-cytochrome c reductase and NADPH-cytochrome c reductase, as well as two chemical reductive activating agents Na2S2O4 and H2/PtO2 were employed as activators for the alkylation of DNA by MC. DTD as well as all the other activators generated the four known major guanine-N2-MC adducts at both pHs. In addition, at the lower pH, the guanine-N7-linked adducts of 2,7-diaminomitosene were detectable in the adduct patterns. At a given pH all the enzymatic and chemical reducing agents generated very similar adduct patterns which, however, differed dramatically at the acidic as compared to the neutral pH. Overall yield of MC adducts was 3-4-fold greater at pH 7.4 than at 5. 8 except in the case of DTD when it was 4-fold lower. Without exception, however, cross-link adduct yields were greater at the acidic pH (2-10-fold within the series). The ratio of adducts of bifunctional activation to those of monofunctional activation was 6-20-fold higher at the acidic as compared to the neutral pH. A comprehensive mechanism of the alkylation of DNA by activated MC was derived from the DNA adduct analysis which complements earlier model studies of the activation of MC. The mechanism consists of three competing activation pathways yielding three different DNA-reactive electrophiles 11, 12, and 17 which generate three unique sets of DNA adducts as endproducts. The relative amounts of these adducts are diagnostic of the relative rates of the competing pathways in vitro, and most likely, in vivo. Factors that influence the relative rates of individual pathways

  12. A NEW ASSOCIATION RULE MINING BASED ON FREQUENT ITEM SET

    Directory of Open Access Journals (Sweden)

    Ms. Sanober Shaikh

    2011-09-01

    Full Text Available In this paper a new mining algorithm is defined based on frequent item set. Apriori Algorithm scans the database every time when it finds the frequent item set so it is very time consuming and at each step it generates candidate item set. So for large databases it takes lots of space to store candidate item set. The defined algorithm scans the database at the start only once and then makes the undirected item set graph. From this graph by considering minimum support it finds the frequent item set and by considering the minimum confidence it generates the association rule. If database and minimum support is changed, the new algorithm finds the new frequent items by scanning undirected item set graph. That is why it’s executing efficiency is improved distinctly compared to traditional algorithm.

  13. Evaluation of item candidates: the PROMIS qualitative item review.

    Science.gov (United States)

    DeWalt, Darren A; Rothrock, Nan; Yount, Susan; Stone, Arthur A

    2007-05-01

    One of the PROMIS (Patient-Reported Outcome Measurement Information System) network's primary goals is the development of a comprehensive item bank for patient-reported outcomes of chronic diseases. For its first set of item banks, PROMIS chose to focus on pain, fatigue, emotional distress, physical function, and social function. An essential step for the development of an item pool is the identification, evaluation, and revision of extant questionnaire items for the core item pool. In this work, we also describe the systematic process wherein items are classified for subsequent statistical processing by the PROMIS investigators. Six phases of item development are documented: identification of extant items, item classification and selection, item review and revision, focus group input on domain coverage, cognitive interviews with individual items, and final revision before field testing. Identification of items refers to the systematic search for existing items in currently available scales. Expert item review and revision was conducted by trained professionals who reviewed the wording of each item and revised as appropriate for conventions adopted by the PROMIS network. Focus groups were used to confirm domain definitions and to identify new areas of item development for future PROMIS item banks. Cognitive interviews were used to examine individual items. Items successfully screened through this process were sent to field testing and will be subjected to innovative scale construction procedures.

  14. A Comparison of Anchor-Item Designs for the Concurrent Calibration of Large Banks of Likert-Type Items

    Science.gov (United States)

    Garcia-Perez, Miguel A.; Alcala-Quintana, Rocio; Garcia-Cueto, Eduardo

    2010-01-01

    Current interest in measuring quality of life is generating interest in the construction of computerized adaptive tests (CATs) with Likert-type items. Calibration of an item bank for use in CAT requires collecting responses to a large number of candidate items. However, the number is usually too large to administer to each subject in the…

  15. Reduction of cell viability induced by IFN-alpha generates impaired data on antiviral assay using Hep-2C cells.

    Science.gov (United States)

    de Oliveira, Edson R A; Lima, Bruna M M P; de Moura, Wlamir C; Nogueira, Ana Cristina M de A

    2013-12-31

    Type I interferons (IFNs) exert an array of important biological functions on the innate immune response and has become a useful tool in the treatment of various diseases. An increasing demand in the usage of recombinant IFNs, mainly due to the treatment of chronic hepatitis C infection, augmented the need of quality control for this biopharmaceutical. A traditional bioassay for IFN potency assessment is the cytopathic effect reduction antiviral assay where a given cell line is preserved by IFN from a lytic virus activity using the cell viability as a frequent measure of end point. However, type I IFNs induce other biological effects such as cell-cycle arrest and apoptosis that can influence directly on viability of many cell lines. Here, we standardized a cytopathic effect reduction antiviral assay using Hep-2C cell/mengovirus combination and studied a possible impact of cell viability variations caused by IFN-alpha 2b on responses generated on the antiviral assay. Using the four-parameter logistic model, we observed less correlation and less linearity on antiviral assay when responses from IFN-alpha 2b 1000 IU/ml were considered in the analysis. Cell viability tests with MTT revealed a clear cell growth inhibition of Hep-2C cells under stimulation with IFN-alpha 2b. Flow cytometric cell-cycle analysis and apoptosis assessment showed an increase of S+G2 phase and higher levels of apoptotic cells after treatment with IFN-alpha 2b 1000 IU/ml under our standardized antiviral assay procedure. Considering our studied dose range, we also observed strong STAT1 activation on Hep-2C cells after stimulation with the higher doses of IFN-alpha 2b. Our findings showed that the reduction of cell viability driven by IFN-alpha can cause a negative impact on antiviral assays. We assume that the cell death induction and the cell growth inhibition effect of IFNs should also be considered while employing antiviral assay protocols in a quality control routine and emphasizes the

  16. Dimensionality reduction in nonlinear optical datasets via diffusion mapping: case study of short-pulse second harmonic generation

    Science.gov (United States)

    Romanov, Dmitri; Smith, Stanley; Brady, John; Levis, Robert J.

    2008-02-01

    We have studied the application of the diffusion mapping technique to dimensionality reduction and clustering in multidimensional optical datasets. The combinational (input-output) data were obtained by sampling search spaces related to optimization of a nonlinear physical process, short-pulse second harmonic generation. The diffusion mapping technique hierarchically reduces the dimensionality of the data set and unifies the statistics of input (the pulse shape) and output (the integral output intensity) parameters. The information content of the emerging clustered pattern can be optimized by modifying the parameters of the mapping procedure. The low-dimensional pattern captures essential features of the nonlinear process, based on a finite sampling set. In particular, the apparently parabolic two-dimensional projection of this pattern exhibits regular evolution with the increase of higher-intensity data in the sampling set. The basic shape of the pattern and the evolution are relatively insensitive to the size of the sampling set, as well as to the details of the mapping procedure. Moreover, the experimental data sets and the sets produced numerically on the basis of a theoretical model are mapped into patterns of remarkable similarity (as quantified by the similarity of the related quadratic-form coefficients). The diffusion mapping method is robust and capable of predicting higher-intensity points from a set of low-intensity points. With these attractive features, diffusion mapping stands poised to become a helpful statistical tool for preprocessing analysis of vast and multidimensional combinational optical datasets.

  17. Heat transfer enhancement accompanying pressure-loss reduction with winglet-type vortex generators for fin-tube heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Torii, K.; Kwak, K.M.; Nishino, K. [Yokohama National Univ. (Japan). Dept. of Mechanical Engineering

    2002-08-01

    This paper proposes a novel technique that can augment heat transfer but nevertheless can reduce pressure-loss in a fin-tube heat exchanger with circular tubes in a relatively low Reynolds number flow, by deploying delta winglet-type vortex generators. The winglets are placed with a heretofore-unused orientation for the purpose of augmentation of heat transfer. This orientation is known as ''common flow up'' configuration. The proposed configuration causes significant separation delay, reduces form drag, and removes the zone of poor heat transfer from the near-wake of the tubes. This enhancement strategy has been successfully verified by experiments in the proposed configuration. In case of staggered tube banks, the heat transfer was augmented by 30% to 10%, and yet the pressure loss was reduced by 55% to 34% for the Reynolds number (based on two times channel height) ranging from 350 to 2100, when the present winglets were added. In case of in-line tube banks, these were found to be 20% to 10% augmentation, and 15% to 8% reduction, respectively. (author)

  18. A global approach to turbomachinery flow control: Loss reduction using endwall suction and midspan vortex generator jet blowing

    Science.gov (United States)

    Bloxham, Matthew Jon

    A flow control scheme using endwall suction and vortex generator jet (VGJ) blowing was employed in an effort to reduce the turbine passage losses associated with the endwall flow field and midspan separation. Unsteady midspan control at low Re had a significant impact on the wake area-average total pressure losses, decreasing the losses by 54%. Initially, the focus of the endwall control was the horseshoe vortex system. The addition of leading edge endwall suction resulted in an area-average total pressure loss reduction of 57%. The minimal additional gains achieved with leading edge endwall suction showed that the horseshoe vortex was a secondary contributor to endwall loss production (primary contributor-passage vortex). A similar flow control strategy was then employed with an emphasis on passage vortex (PV) control. During the design, a theoretical model was used that effectively predicted the trajectory of the passage vortex. The model required inviscid results obtained from two-dimensional CFD. It was used in the design of two flow control approaches, the removal and redirection approaches. The emphasis of the removal approach was the direct application of flow control on the endwall below the passage vortex trajectory. The redirection approach attempted to alter the trajectory of the PV by removing boundary layer fluid through judiciously placed suction holes. Suction hole positions were chosen using a potential flow model that emphasized the alignment of the endwall flow field with inviscid streamlines. Model results were validated using flow visualization and particle image velocimetry (PIV) in a linear turbine cascade comprised of the highly-loaded L1A blade profile. Detailed wake total pressure losses were measured while matching the suction and VGJ massflow rates, for the removal and redirection approaches at ReCx=25000 and blowing ratio, B, of 2. When compared with the no control results, the addition of steady VGJs and endwall suction reduced the wake

  19. Phosphate Shifted Oxygen Reduction Pathway on Fe@Fe2O3 Core-Shell Nanowires for Enhanced Reactive Oxygen Species Generation and Aerobic 4-Chlorophenol Degradation.

    Science.gov (United States)

    Mu, Yi; Ai, Zhihui; Zhang, Lizhi

    2017-07-18

    Phosphate ions widely exist in the environment. Previous studies revealed that the adsorption of phosphate ions on nanoscale zerovalent iron would generate a passivating oxide shell to block reactive sites and thus decrease the direct pollutant reduction reactivity of zerovalent iron. Given that molecular oxygen activation process is different from direct pollutant reduction with nanoscale zerovalent iron, it is still unclear how phosphate ions will affect molecular oxygen activation and reactive oxygen species generation with nanoscale zerovalent iron. In this study, we systematically studied the effect of phosphate ions on molecular oxygen activation with Fe@Fe2O3 nanowires, a special nanoscale zerovalent iron, taking advantages of rotating ring disk electrochemical analysis. It was interesting to find that the oxygen reduction pathway on Fe@Fe2O3 nanowires was gradually shifted from a four-electron reduction pathway to a sequential one-electron reduction one, along with increasing the phosphate ions concentration from 0 to 10 mmol·L(-1). This oxygen reduction pathway change greatly enhanced the molecular oxygen activation and reactive oxygen species generation performances of Fe@Fe2O3 nanowires, and thus increased their aerobic 4-chlorophenol degradation rate by 10 times. These findings shed insight into the possible roles of widely existed phosphate ions in molecular oxygen activation and organic pollutants degradation with nanoscale zerovalent iron.

  20. Mathematical modeling of a multi-product EMQ model with an enhanced end items issuing policy and failures in rework.

    Science.gov (United States)

    Chiu, Yuan-Shyi Peter; Sung, Peng-Cheng; Chiu, Singa Wang; Chou, Chung-Li

    2015-01-01

    This study uses mathematical modeling to examine a multi-product economic manufacturing quantity (EMQ) model with an enhanced end items issuing policy and rework failures. We assume that a multi-product EMQ model randomly generates nonconforming items. All of the defective are reworked, but a certain portion fails and becomes scraps. When rework process ends and the entire lot of each product is quality assured, a cost reduction n + 1 end items issuing policy is used to transport finished items of each product. As a result, a closed-form optimal production cycle time is obtained. A numerical example demonstrates the practical usage of our result and confirms a significant savings in stock holding and overall production costs as compared to that of a prior work (Chiu et al. in J Sci Ind Res India, 72:435-440 2013) in the literature.

  1. Resolution Improvement and Pattern Generator Development for theMaskless Micro-Ion-Beam Reduction Lithography System

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Ximan [Univ. of California, Berkeley, CA (United States)

    2006-05-18

    The shrinking of IC devices has followed the Moore's Law for over three decades, which states that the density of transistors on integrated circuits will double about every two years. This great achievement is obtained via continuous advance in lithography technology. With the adoption of complicated resolution enhancement technologies, such as the phase shifting mask (PSM), the optical proximity correction (OPC), optical lithography with wavelength of 193 nm has enabled 45 nm printing by immersion method. However, this achievement comes together with the skyrocketing cost of masks, which makes the production of low volume application-specific IC (ASIC) impractical. In order to provide an economical lithography approach for low to medium volume advanced IC fabrication, a maskless ion beam lithography method, called Maskless Micro-ion-beam Reduction Lithography (MMRL), has been developed in the Lawrence Berkeley National Laboratory. The development of the prototype MMRL system has been described by Dr. Vinh Van Ngo in his Ph.D. thesis. But the resolution realized on the prototype MMRL system was far from the design expectation. In order to improve the resolution of the MMRL system, the ion optical system has been investigated. By integrating a field-free limiting aperture into the optical column, reducing the electromagnetic interference and cleaning the RF plasma, the resolution has been improved to around 50 nm. Computational analysis indicates that the MMRL system can be operated with an exposure field size of 0.25 mm and a beam half angle of 1.0 mrad on the wafer plane. Ion-ion interactions have been studied with a two-particle physics model. The results are in excellent agreement with those published by the other research groups. The charge-interaction analysis of MMRL shows that the ion-ion interactions must be reduced in order to obtain a throughput higher than 10 wafers per hour on 300-mm wafers. In addition, two different maskless lithography

  2. Item response theory for measurement validity.

    Science.gov (United States)

    Yang, Frances M; Kao, Solon T

    2014-06-01

    Item response theory (IRT) is an important method of assessing the validity of measurement scales that is underutilized in the field of psychiatry. IRT describes the relationship between a latent trait (e.g., the construct that the scale proposes to assess), the properties of the items in the scale, and respondents' answers to the individual items. This paper introduces the basic premise, assumptions, and methods of IRT. To help explain these concepts we generate a hypothetical scale using three items from a modified, binary (yes/no) response version of the Center for Epidemiological Studies-Depression scale that was administered to 19,399 respondents. We first conducted a factor analysis to confirm the unidimensionality of the three items and then proceeded with Mplus software to construct the 2-Parameter Logic (2-PL) IRT model of the data, a method which allows for estimates of both item discrimination and item difficulty. The utility of this information both for clinical purposes and for scale construction purposes is discussed.

  3. How French subjects describe well-being from food and eating habits? Development, item reduction and scoring definition of the Well-Being related to Food Questionnaire (Well-BFQ©).

    Science.gov (United States)

    Guillemin, I; Marrel, A; Arnould, B; Capuron, L; Dupuy, A; Ginon, E; Layé, S; Lecerf, J-M; Prost, M; Rogeaux, M; Urdapilleta, I; Allaert, F-A

    2016-01-01

    Providing well-being and maintaining good health are main objectives subjects seek from diet. This manuscript describes the development and preliminary validation of an instrument assessing well-being associated with food and eating habits in a general healthy population. Qualitative data from 12 groups of discussion (102 subjects) conducted with healthy subjects were used to develop the core of the Well-being related to Food Questionnaire (Well-BFQ). Twelve other groups of discussion with subjects with joint (n = 34), digestive (n = 32) or repetitive infection complaints (n = 30) were performed to develop items specific to these complaints. Five main themes emerged from the discussions and formed the modular backbone of the questionnaire: "Grocery shopping", "Cooking", "Dining places", "Commensality", "Eating and drinking". Each module has a common structure: items about subject's food behavior and items about immediate and short-term benefits. An additional theme - "Eating habits and health" - assesses subjects' beliefs about expected benefits of food and eating habits on health, disease prevention and protection, and quality of ageing. A preliminary validation was conducted with 444 subjects with balanced diet; non-balanced diet; and standard diet. The structure of the questionnaire was further determined using principal component analyses exploratory factor analyses, with confirmation of the sub-sections food behaviors, immediate benefits (pleasure, security, relaxation), direct short-term benefits (digestion and satiety, energy and psychology), and deferred long-term benefits (eating habits and health). Thirty-three subscales and 14 single items were further defined. Confirmatory analyses confirmed the structure, with overall moderate to excellent convergent and divergent validity and internal consistency reliability. The Well-BFQ is a unique, modular tool that comprehensively assesses the full picture of well-being related to food and eating habits in

  4. Emergency Power For Critical Items

    Science.gov (United States)

    Young, William R.

    2009-07-01

    Natural disasters, such as hurricanes, floods, tornados, and tsunami, are becoming a greater problem as climate change impacts our environment. Disasters, whether natural or man made, destroy lives, homes, businesses and the natural environment. Such disasters can happen with little or no warning, leaving hundreds or even thousands of people without medical services, potable water, sanitation, communications and electrical services for up to several weeks. In our modern world, the need for electricity has become a necessity. Modern building codes and new disaster resistant building practices are reducing the damage to homes and businesses. Emergency gasoline and diesel generators are becoming common place for power outages. Generators need fuel, which may not be available after a disaster, but Photovoltaic (solar-electric) systems supply electricity without petroleum fuel as they are powered by the sun. Photovoltaic (PV) systems can provide electrical power for a home or business. PV systems can operate as utility interactive or stand-alone with battery backup. Determining your critical load items and sizing the photovoltaic system for those critical items, guarantees their operation in a disaster.

  5. SHIPPING OF RADIOACTIVE ITEMS

    CERN Multimedia

    TIS/RP Group

    2001-01-01

    The TIS-RP group informs users that shipping of small radioactive items is normally guaranteed within 24 hours from the time the material is handed in at the TIS-RP service. This time is imposed by the necessary procedures (identification of the radionuclides, determination of dose rate and massive objects require a longer procedure and will therefore take longer.

  6. Item Banking with Embedded Standards

    Science.gov (United States)

    MacCann, Robert G.; Stanley, Gordon

    2009-01-01

    An item banking method that does not use Item Response Theory (IRT) is described. This method provides a comparable grading system across schools that would be suitable for low-stakes testing. It uses the Angoff standard-setting method to obtain item ratings that are stored with each item. An example of such a grading system is given, showing how…

  7. Item Banking with Embedded Standards

    Science.gov (United States)

    MacCann, Robert G.; Stanley, Gordon

    2009-01-01

    An item banking method that does not use Item Response Theory (IRT) is described. This method provides a comparable grading system across schools that would be suitable for low-stakes testing. It uses the Angoff standard-setting method to obtain item ratings that are stored with each item. An example of such a grading system is given, showing how…

  8. Development of the asperity-matrix structure in fault zones: a model for strength reduction and generation of earthquakes

    Science.gov (United States)

    Takeshita, T.

    2014-12-01

    Seismologists have now believed that the fault interface is characterized by the asperity-matrix structure, where the upper and lower plates are strongly coupled at the asperity, and the matrix, which surrounds the asperity, is deformed by creeping. Earthquakes are generated by dynamic rupture only in the non-creeping hard asperity, where the strain energy is accumulated if the asperity and matrix are mechanically coupled to a certain degree. In this presentation, we will argue that this structure is developed as brittle fracturing proceeds aided by dissolution-precipitation creep in particular at the brittle-ductile transition zone, which leads to the strength reduction and seimogenesis in both crust and subduction zones. We have been studying deformation processes and mechanisms in rocks at brittle-ductile transition conditions, based on microstructural analyses in naturally deformed rocks. For example, we reported that pervasive micro-faulting in the high-P/T Sambagawa quartz schist at brittle-ductile transition conditions, where a volume fraction of micro-shear zones consisting of both very-fine grained dynamically recrystallized quartz and white mica increased with increasing deformation (Takeshita and El-Fakharani, 2013). We believe that the resultant structure, "undeformed lenses surrounded by microshear zones" can be correlated with the asperity-matrix structure in the thin section scale, which could have occurred in the mesoscopic to macroscopic scales (cf. Schrank et al., 2008). It is inferred that the rocks became softened with increasing volume fraction of micro-shear zones, because dissolution-precipitation creep could have occurred at low differential stresses in the sheared zones. Further, cataclasites were formed along the Median Tectonic Line in the Cretaceous to Paleogene, where new minerals precipitated from fluids in the space created by fracturing at the conditions of brittle-ductile transition. The fracturing was accompanied by element

  9. An Estimation of Reduction of the Primary Energy and the CO2 Emission in Residential PEFC Co-Generation System with Li-ion Battery Modules

    Science.gov (United States)

    Maeda, Kazushige; Yonemori, Hideto; Yasaka, Yasuyoshi

    This paper presents the effects of introduction of residential polymer electrolyte fuel cell (PEFC) co-generation system with batteries in comparison with conventional systems that consist of a gas boiler and electric power from commercial grid, by computer simulation. The PEFC co-generation system in commercial use provides the average primary energy saving rate of 12.7% and CO2 reduction rate of 15.4% with respect to the conventional system. Addition of 8.0-kWh batteries to the PEFC system results in limited improvements of 0.8 points and 0.9 points in the reduction rates, respectively, yielding 13.5% and 16.3%, when using a conventional operation planning method. A new operation planning method is proposed in order to make a precise control of charging and discharging the batteries. The average primary energy saving rate reaches up to 16.9% by the improvement of 4.2 points, and CO2 reduction rate reaches up to 20.4% by the improvement of 5.0 points in the PEFC co-generation system with 8.0-kWh batteries using the new operation planning method. The new method can thus realize a substantial improvement in reduction rates. Furthermore, it is shown that the suitable battery module capacity for the residential PEFC co-generation system is 4.0kWh.

  10. Generations.

    Science.gov (United States)

    Chambers, David W

    2005-01-01

    Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession.

  11. SHIPPING OF RADIOACTIVE ITEMS

    CERN Multimedia

    TIS/RP Group

    2001-01-01

    The TIS-RP group informs users that shipping of small radioactive items is normally guaranteed within 24 hours from the time the material is handed in at the TIS-RP service. This time is imposed by the necessary procedures (identification of the radionuclides, determination of dose rate, preparation of the package and related paperwork). Large and massive objects require a longer procedure and will therefore take longer.

  12. Designing a Virtual Item Bank Based on the Techniques of Image Processing

    Science.gov (United States)

    Liao, Wen-Wei; Ho, Rong-Guey

    2011-01-01

    One of the major weaknesses of the item exposure rates of figural items in Intelligence Quotient (IQ) tests lies in its inaccuracies. In this study, a new approach is proposed and a useful test tool known as the Virtual Item Bank (VIB) is introduced. The VIB combine Automatic Item Generation theory and image processing theory with the concepts of…

  13. Faculty development on item writing substantially improves item quality.

    NARCIS (Netherlands)

    Naeem, N.; Vleuten, C.P.M. van der; Alfaris, E.A.

    2012-01-01

    The quality of items written for in-house examinations in medical schools remains a cause of concern. Several faculty development programs are aimed at improving faculty's item writing skills. The purpose of this study was to evaluate the effectiveness of a faculty development program in item develo

  14. IRT Item Parameter Scaling for Developing New Item Pools

    Science.gov (United States)

    Kang, Hyeon-Ah; Lu, Ying; Chang, Hua-Hua

    2017-01-01

    Increasing use of item pools in large-scale educational assessments calls for an appropriate scaling procedure to achieve a common metric among field-tested items. The present study examines scaling procedures for developing a new item pool under a spiraled block linking design. The three scaling procedures are considered: (a) concurrent…

  15. An approach of attribute reduction based on FCM and its application in fault diagnosis on turbo-generator unit%FCM属性约简方法在汽轮机故障诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    齐晓轩; 纪建伟; 原忠虎

    2011-01-01

    Fuzzy c-means(FCM) clustering method is applied to discretizing continuous attributes of turbo-generator unit faults by the analysis of spatial distribution of pattern datasets. The attribute reduction algorithm for rough set(RS) is utilized to optimize original feature vectors of turbo-generator unit faults, eliminate redundant information and extract essential information of feature vectors. Fault diagnosis model based on support vector machine(SVM) is built up according to the reduced feature vectors. Experimental results demonstrate that the proposed method can improve the accuracy and real-time performance of fault diagnosis, decrease the number of test items and accordingly cut down the cost of fault diagnosis on turbo-generator unit.%文章通过汽轮机故障样本数据的空间分布状态分析,基于模糊c均值(FCM)聚类方法实现故障征兆参数属性的离散化处理;采用粗糙集(RS)属性约简方法对原始特征向量进行优化,去除冗余特征,提取特征向量的本质信息;基于约简后的特征向量建立支持向量机(SVM)故障诊断模型.实验结果表明,该文所提出的方法不仅可以提高故障诊断的准确性和实时性,还可以减少故障检测项目,降低故障诊断成本.

  16. Generation IV Nuclear Energy Systems Construction Cost Reductions through the Use of Virtual Environments - Task 5 Report: Generation IV Reactor Virtual Mockup Proof-of-Principle Study

    Energy Technology Data Exchange (ETDEWEB)

    Timothy Shaw; Anthony Baratta; Vaughn Whisker

    2005-02-28

    Task 5 report is part of a 3 year DOE NERI-sponsored effort evaluating immersive virtual reality (CAVE) technology for design review, construction planning, and maintenance planning and training for next generation nuclear power plants. Program covers development of full-scale virtual mockups generated from 3D CAD data presented in a CAVE visualization facility. Created a virtual mockup of PBMR reactor cavity and discussed applications of virtual mockup technology to improve Gen IV design review, construction planning, and maintenance planning.

  17. Item Overexposure in Computerized Classification Tests Using Sequential Item Selection

    Directory of Open Access Journals (Sweden)

    Alan Huebner

    2012-06-01

    Full Text Available Computerized classification tests (CCTs often use sequential item selection which administers items according to maximizing psychometric information at a cut point demarcating passing and failing scores. This paper illustrates why this method of item selection leads to the overexposure of a significant number of items, and the performances of three different methods for controlling maximum item exposure rates in CCTs are compared. Specifically, the Sympson-Hetter, restricted, and item eligibility methods are examined in two studies realistically simulating different types of CCTs and are evaluated based upon criteria including classification accuracy, the number of items exceeding the desired maximum exposure rate, and test overlap. The pros and cons of each method are discussed from a practical perspective.

  18. Efficacy of a dynamic collimator for overranging dose reduction in a second- and third-generation dual source CT scanner

    NARCIS (Netherlands)

    R. Booij (Ronald); M.L. Dijkshoorn (Marcel); M. van Straten (Marcel)

    2017-01-01

    textabstractObjectives: The purpose of this study was to assess the efficacy of the renewed dynamic collimator in a third-generation dual source CT (DSCT) scanner and to determine the improvements over the second-generation scanner. Methods: Collimator efficacy is defined as the percentage overrangi

  19. An optimized item-based collaborative filtering recommendation algorithm based on item genre prediction

    Science.gov (United States)

    Zhang, De-Jia

    2009-07-01

    With the fast development of Internet, many systems have emerged in e-commerce applications to support the product recommendation. Collaborative filtering is one of the most promising techniques in recommender systems, providing personalized recommendations to users based on their previously expressed preferences in the form of ratings and those of other similar users. In practice, with the adding of user and item scales, user-item ratings are becoming extremely sparsity and recommender systems utilizing traditional collaborative filtering are facing serious challenges. To address the issue, this paper presents an approach to compute item genre similarity, through mapping each item with a corresponding descriptive genre, and computing similarity between genres as similarity, then make basic predictions according to those similarities to lower sparsity of the user-item ratings. After that, item-based collaborative filtering steps are taken to generate predictions. Compared with previous methods, the presented collaborative filtering employs the item genre similarity can alleviate the sparsity issue in the recommender systems, and can improve accuracy of recommendation.

  20. Mechanistic aspects of the oxidative and reductive fragmentation of n-nitrosoamines: a new method for generating nitrenium cations, amide anions, and aminyl radicals

    OpenAIRE

    Piech, Krzysztof; Bally, Thomas; Sikora, Adam; Marcinek, Andrzej

    2008-01-01

    A new method for investigating the mechanisms of nitric oxide release from NO donors under oxidative and reductive conditions is presented. Based on the fragmentation of N-nitrosoamines, it allows generation and spectroscopic characterization of nitrenium cations, amide anions, and aminyl radicals. X-irradiation of N-nitroso-N,N-diphenylamine 1 in Ar matrices at 10 K is found to yield the corresponding radical ions, which apparently undergo spontaneous loss of NO° under the conditions of this...

  1. A Survey of Municipal Solid Waste Generation in 22 Regions of Tehran With Solid Waste Reduction Approach

    Directory of Open Access Journals (Sweden)

    MA Abduli

    2015-07-01

    Methods: The study was a descriptive cross-sectional one conducted from 2010 to 2014. Relevant officials of the waste recovery in 22 regions of Tehran were approached in order to collect data about municipal solid waste generation through interviewing, filling out questionnaires, conducting field visits from Aradkooh Disposal and Processing Complex and collecting information on disposal and destiny of wastes. Then the data were compiled and analyzed. Results: Total solid waste generation in Tehran from 2010 to 2014 amounted to respectively 3389662, 3399344, 3449338 and 3245157 Metric Tons, categorized into three groups of municipal, companies and townships and hospital wastes. Most of the generated waste produced in Tehran was that of households and commercial (known as municipal waste from 22 Regions of Tehran. Based on the surveys conducted, per capita solid waste generation of 11 regions of Tehran ranged from 550 to 1000 grams and in other 11 ones from 1000 to 1521 grams per capita per day. The lowest and highest waste generation rate belonged respectively to region 13 with 556 grams and region 12 with 1521 grams per capita per day in 2011. Conclusion: Comparing per capita generation of municipal solid waste in different municipal regions in Tehran with maximum acceptable capacity of waste generation indicates the deviation of waste generation of all Tehran regions from the standard acceptable amount. Therefore, not only is it necessary to plan and take strategic measures to reduce Tehran waste generation but also these programs and measures should be specific to each region considering its specifications and solid waste quality and quantity.

  2. Generation and reduction of nitrogen oxides in firing different kinds of fuel in a circulating fluidized bed

    Science.gov (United States)

    Munts, V. A.; Munts, Yu. G.; Baskakov, A. P.; Proshin, A. S.

    2013-11-01

    The processes through which nitrogen oxides are generated and reduced in the course of firing different kinds of fuel in a circulating fluidized bed are addressed. All experimental studies were carried by the authors on their own laboratory installations. To construct a model simulating the generation of nitrogen oxides, the fuel combustion process in a fluidized bed was subdivided into two stages: combustion of volatiles and combustion of coke residue. The processes through which nitrogen oxides are generated and reduced under the conditions of firing fuel with shortage of oxygen (which is one of efficient methods for reducing nitrogen oxide emissions in firing fuel in a fluidized bed) are considered.

  3. How do drug users define their progress in harm reduction programs? Qualitative research to develop user-generated outcomes

    Directory of Open Access Journals (Sweden)

    Ruefli Terry

    2004-08-01

    Full Text Available Abstract Background Harm reduction is a relatively new and controversial model for treating drug users, with little formal research on its operation and effectiveness. In order to advance the study of harm reduction programs and our understanding of how drug users define their progress, qualitative research was conducted to develop outcomes of harm reduction programming that are culturally relevant, incremental, (i.e., capable of measuring change, and hierarchical (i.e., capable of showing how clients improve over time. Methods The study used nominal group technique (NGT to develop the outcomes (phase 1 and focus group interviews to help validate the findings (phase 2. Study participants were recruited from a large harm-reduction program in New York City and involved approximately 120 clients in 10 groups in phase 1 and 120 clients in 10 focus groups in phase 2. Results Outcomes of 10 life areas important to drug users were developed that included between 10 to 15 incremental measures per outcome. The outcomes included ways of 1 making money; 2 getting something good to eat; 3 being housed/homeless; 4 relating to families; 5 getting needed programs/benefits/services; 6 handling health problems; 7 handling negative emotions; 8 handling legal problems; 9 improving oneself; and 10 handling drug-use problems. Findings also provided insights into drug users' lives and values, as well as a window into understanding how this population envisions a better quality of life. Results challenged traditional ways of measuring drug users based solely on quantity used and frequency of use. They suggest that more appropriate measures are based on the extent to which drug users organize their lives around drug use and how much drug use is integrated into their lives and negatively impacts other aspects of their lives. Conclusions Harm reduction and other programs serving active drug users and other marginalized people should not rely on institutionalized

  4. New approaches for the reduction of plasma arc drop in second-generation thermionic converters. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hatziprokopiou, M.E.; Shaw, D.T.

    1981-03-31

    Investigations of ion generation and recombination mechanisms in the cesium plasma as they pertain to the advanced mode thermionic energy converter are described. The changes in plasma density and temperature within the converter have been studied under the influence of several promising auxiliary ionization candidate sources. Three novel approaches of external cesium ion generation have been investigated in some detail, namely vibrationally excited N/sub 2/ as an energy source of ionization of Cs ions in a DC discharge, microwave power as a means of resonant sustenance of the cesium plasma, and ion generation in a pulse N/sub 2/-Cs mixture. The experimental data obtained and discussed show that all three techniques - i.e. the non-LTE high-voltage pulsing, the energy transfer from vibrationally excited diatomic gases, and the external pumping with a microwave power - have considerable promise as schemes in auxiliary ion generation applicable to the advanced thermionic energy converter.

  5. Efficacy of a dynamic collimator for overranging dose reduction in a second- and third-generation dual source CT scanner

    OpenAIRE

    Booij, Ronald; Dijkshoorn, Marcel; Straten, Marcel

    2017-01-01

    textabstractObjectives: The purpose of this study was to assess the efficacy of the renewed dynamic collimator in a third-generation dual source CT (DSCT) scanner and to determine the improvements over the second-generation scanner. Methods: Collimator efficacy is defined as the percentage overranging dose in terms of dose–length product (DLP) that is blocked by the dynamic collimator relative to the total overranging dose in case of a static collimator. Efficacy was assessed at various pitch...

  6. Bayesian item fit analysis for unidimensional item response theory models.

    Science.gov (United States)

    Sinharay, Sandip

    2006-11-01

    Assessing item fit for unidimensional item response theory models for dichotomous items has always been an issue of enormous interest, but there exists no unanimously agreed item fit diagnostic for these models, and hence there is room for further investigation of the area. This paper employs the posterior predictive model-checking method, a popular Bayesian model-checking tool, to examine item fit for the above-mentioned models. An item fit plot, comparing the observed and predicted proportion-correct scores of examinees with different raw scores, is suggested. This paper also suggests how to obtain posterior predictive p-values (which are natural Bayesian p-values) for the item fit statistics of Orlando and Thissen that summarize numerically the information in the above-mentioned item fit plots. A number of simulation studies and a real data application demonstrate the effectiveness of the suggested item fit diagnostics. The suggested techniques seem to have adequate power and reasonable Type I error rate, and psychometricians will find them promising.

  7. Hydroxyl radical generation caused by the reaction of singlet oxygen with a spin trap, DMPO, increases significantly in the presence of biological reductants.

    Science.gov (United States)

    Nishizawa, Chiho; Takeshita, Keizo; Ueda, Jun-ichi; Mizuno, Michiko; Suzuki, Kazuo T; Ozawa, Toshihiko

    2004-04-01

    Photosensitizers newly developed for photodynamic therapy of cancer need to be assessed using accurate methods of measuring reactive oxygen species (ROS). Little is known about the characteristics of the reaction of singlet oxygen (1O2) with spin traps, although this knowledge is necessary in electron spin resonance (ESR)/spin trapping. In the present study, we examined the effect of various reductants usually present in biological samples on the reaction of 1O2 with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The ESR signal of the hydroxyl radical (*OH) adduct of DMPO (DMPO-OH) resulting from 1O2-dependent generation of *OH strengthened remarkably in the presence of reduced glutathione (GSH), 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), ascorbic acid, NADPH, etc. A similar increase was observed in the photosensitization of uroporphyrin (UP), rose bengal (RB) or methylene blue (MB). Use of 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO) as a spin trap significantly lessened the production of its *OH adduct (DEPMPO-OH) in the presence of the reductants. The addition of DMPO to the DEPMPO-spin trapping system remarkably increased the signal intensity of DEPMPO-OH. DMPO-mediated generation of *OH was also confirmed utilizing the hydroxylation of salicylic acid (SA). These results suggest that biological reductants enhance the ESR signal of DMPO-OH produced by DMPO-mediated generation of *OH from 1O2, and that spin trap-mediated *OH generation hardly occurs with DEPMPO.

  8. Burners. Reduction of nitrogen oxides in combustion: 2. generation of GR LONOxFLAM burner; Les bruleurs. La reduction des oxydes d`azote dans la combustion: bruleur GR LONOxFLAM de 2. generation

    Energy Technology Data Exchange (ETDEWEB)

    Gauthier, J.C. [EGCI Pillard, 13 - Marseille (France)

    1997-12-31

    This paper presents the research work carried out by the French Pillard company in collaboration with Gaz de France for the design of low NO{sub x} burners. The different type of low NO{sub x} burners are presented according to the type of fuel: gas, liquid fuels and fuel oils. The gas burner uses the fuel staging principle and the recirculation of smokes and leads to NO{sub x} emissions lower than 100 mg/Nm{sup 3}. The liquid fuel and fuel oil burners use the separate flames and the smoke self-recirculation methods (fuel-air mixture staging, reduction of flame temperature and of the residence time in flames). (J.S.)

  9. Cost reduction in the cold: heat generated by terrestrial locomotion partly substitutes for thermoregulation costs in Knot Calidris canutus

    NARCIS (Netherlands)

    Bruinzeel, L.W.; Piersma, T.

    1998-01-01

    To test whether heat generated during locomotion substitutes for the thermoregulation cost, oxygen consumption of four post-absorptive temperate-wintering Knot Calidris canutus was measured at air temperatures of 25 degrees C (thermoneutral) and 10 degrees C (c. 10 degrees below the lower critical

  10. Cost reduction in the cold : heat generated by terrestrial locomotion partly substitutes for thermoregulation costs in Knot Calidris canutus

    NARCIS (Netherlands)

    Bruinzeel, Leo W.; Piersma, T

    To test whether heat generated during locomotion substitutes for the thermoregulation cost, oxygen consumption of four post-absorptive temperate-wintering Knot Calidris canutus was measured at air temperatures of 25 degrees C (thermoneutral) and 10 degrees C (c. 10 degrees below the lower critical

  11. Economic feasibility of second generation ethanol with and without indirect greenhouse gas reduction benefits : a simulation for Brazil

    NARCIS (Netherlands)

    Lagares Tavora, F.; Bakker, R.R.; Stojanovic, M.; Elbersen, H.W.

    2009-01-01

    The aim of this study is to determine the economic feasibility of second generation ethanol from sugar cane, whereby traditional ethanol production is combined with the use of lignocellulosic biomass for ethanol production. By applying cost-benefit analysis, this study evaluated the viability of the

  12. Generating tsunami risk knowledge at community level as a base for planning and implementation of risk reduction strategies

    Directory of Open Access Journals (Sweden)

    S. Wegscheider

    2011-02-01

    Full Text Available More than 4 million Indonesians live in tsunami-prone areas along the southern and western coasts of Sumatra, Java and Bali. Although a Tsunami Early Warning Center in Jakarta now exists, installed after the devastating 2004 tsunami, it is essential to develop tsunami risk knowledge within the exposed communities as a basis for tsunami disaster management. These communities need to implement risk reduction strategies to mitigate potential consequences.

    The major aims of this paper are to present a risk assessment methodology which (1 identifies areas of high tsunami risk in terms of potential loss of life, (2 bridges the gaps between research and practical application, and (3 can be implemented at community level. High risk areas have a great need for action to improve people's response capabilities towards a disaster, thus reducing the risk. The methodology developed here is based on a GIS approach and combines hazard probability, hazard intensity, population density and people's response capability to assess the risk.

    Within the framework of the GITEWS (German-Indonesian Tsunami Early Warning System project, the methodology was applied to three pilot areas, one of which is southern Bali. Bali's tourism is concentrated for a great part in the communities of Kuta, Legian and Seminyak. Here alone, about 20 000 people live in high and very high tsunami risk areas. The development of risk reduction strategies is therefore of significant interest. A risk map produced for the study area in Bali can be used for local planning activities and the development of risk reduction strategies.

  13. Effects of various organic carbon sources on simultaneous V(V) reduction and bioelectricity generation in single chamber microbial fuel cells.

    Science.gov (United States)

    Hao, Liting; Zhang, Baogang; Cheng, Ming; Feng, Chuanping

    2016-02-01

    Four ordinary carbon sources affecting V(V) reduction and bioelectricity generation in single chamber microbial fuel cells (MFCs) were investigated. Acetate supported highest maximum power density of 589.1mW/m(2), with highest V(V) removal efficiency of 77.6% during 12h operation, compared with glucose, citrate and soluble starch. Exorbitant initial V(V) concentration led to lower V(V) removal efficiencies and power outputs. Extra addition of organics had little effect on the improvement of MFCs performance. V(V) reduction and bioelectricity generation were enhanced and then suppressed by the increase of conductivity. The larger the external resistance, the higher the V(V) removal efficiencies and voltage outputs. High-throughput 16S rRNA gene pyrosequencing analysis implied the accumulation of Enterobacter which had the capabilities of V(V) reduction, electrochemical activity and fermentation, accompanied with other functional species as Pseudomonas, Spirochaeta, Sedimentibacter and Dysgonomonas. This study steps forward to remediate V(V) contaminated environment based on MFC technology.

  14. A time and space complexity reduction for coevolutionary analysis of trees generated under both a Yule and Uniform model.

    Science.gov (United States)

    Drinkwater, Benjamin; Charleston, Michael A

    2015-08-01

    The topology or shape of evolutionary trees and their unbalanced nature has been a long standing area of interest in the field of phylogenetics. Coevolutionary analysis, which considers the evolutionary relationships between a pair of phylogenetic trees, has to date not considered leveraging this unbalanced nature as a means to reduce the complexity of coevolutionary analysis. In this work we apply previous analyses of tree shapes to improve the efficiency of inferring coevolutionary events. In particular, we use this prior research to derive a new data structure for inferring coevolutionary histories. Our new data structure is proven to provide a reduction in the time and space required to infer coevolutionary events. It is integrated into an existing framework for coevolutionary analysis and has been validated using both synthetic and previously published biological data sets. This proposed data structure performs twice as fast as algorithms implemented using existing data structures with no degradation in the algorithm's accuracy. As the coevolutionary data sets increase in size so too does the running time reduction provided by the newly proposed data structure. This is due to our data structure offering a logarithmic time and space complexity improvement. As a result, the proposed update to existing coevolutionary analysis algorithms outlined herein should enable the inference of larger coevolutionary systems in the future.

  15. GRE Verbal Analogy Items: Examinee Reasoning on Items.

    Science.gov (United States)

    Duran, Richard P.; And Others

    Information about how Graduate Record Examination (GRE) examinees solve verbal analogy problems was obtained in this study through protocol analysis. High- and low-ability subjects who had recently taken the GRE General Test were asked to "think aloud" as they worked through eight analogy items. These items varied factorially on the…

  16. Generation of keys for image optical encryption in spatially incoherent light aimed at reduction of image decryption error

    Science.gov (United States)

    Cheremkhin, Pavel A.; Evtikhiev, Nikolay N.; Krasnov, Vitaly V.; Rodin, Vladislav G.; Starikov, Sergey N.

    2014-05-01

    At present time methods of optical encryption are actively developed. The majority of existing methods of optical encryption use not only light intensity distribution, easily registered with photosensors, but also its phase distribution which require application of complex holographic schemes in conjunction with spatially coherent light. This leads to complex optical schemes and low decryption quality. To eliminate these disadvantages it is possible to implement optical encryption using spatially incoherent illumination which requires registration of light intensity distribution only. However this applies new restrictions on encryption keys: Fourier spectrum amplitude distribution of encryption key should overlap Fourier spectrum amplitude distribution of image to be encrypted otherwise loss of information is unavoidable. Therefore it seems that best key should have white spectrum. On the other hand due to fact that only light intensity distribution is registered, spectra of image to be encrypted and encryption key always have peaks at zero frequency and their heights depend on corresponding total energy. Since encrypted image contains noise, ratio of its average spectrum energy to noise average energy determines signal to noise ratio of decrypted image. Therefore ratio of amplitude at zero frequency to average spectrum amplitude (RZA) of encryption key defines decrypted images quality. For generation of encryption keys with low RZA method of direct search with random trajectory (DSRT) was used. To estimate impact of key RZA on decrypted images error numerical experiments were conducted. For experiments keys with different RZA values but with same energy value were generated and used. Numerically simulated optical encryption and decryption of set of test images was conducted. Results of experiment demonstrate that application of keys with low RZA generated by DSRT method leads to up to 20% lower error in comparison to keys generated by means of uniform random

  17. A comparison between new dentinal adhesives (fifth generation) and traditional varnish in microleakage reduction of amalgam restorations in primary teeth

    OpenAIRE

    Mortazavi M. Associate Professor; Bahrololoomi Z. Assistant Professor

    2003-01-01

    Statement of Problem: Microleakage presents the major cause for restorations failure in the oral cavity resulting in postoperative sensitivity, pulp irritation and secondary caries formation."nAim: The aim of this study was to compare two dentinal adhesive systems of fifth generation and copalite varnish in reducing microleakage of amalgam restorations in primary teeth."nMaterials and Methods: In this in-vitro study, 100 class V amalgam restorations were prepared on the buccal or li...

  18. Enhanced drought tolerance in Arabidopsis via genetic manipulation aimed at the reduction of glucosamine-induced ROS generation.

    Science.gov (United States)

    Chu, Seung Hee; Noh, Ha-na; Kim, Sooah; Kim, Kyoung Heon; Hong, Suk-Whan; Lee, Hojoung

    2010-11-01

    In animals, high glucose exerts some of its deleterious effects by activation of the hexosamine biosynthesis pathway (HBP), a branch of the glycolytic pathway that produces amino sugars (Daniels et al. in Mol Endocrinol 7:1041-1048, 1993; Du et al. in Proc Natl Acad Sci USA 97:12222-12226, 2000). Glucosamine (GlcN) is a naturally occurring amino sugar produced by amidation of fructose-6-phosphate. Previously, we observed that glucosamine (GlcN) inhibits hypocotyl elongation in Arabidopsis thaliana by a process involving the significant increase of reactive oxygen species. The present study investigated the relationship between GlcN-induced ROS generation and abiotic stress responses in Arabidopsis by generating two types of transgenic plant. Scavenging of endogenous GlcN by ectopic expression of E. coli glucosamine-6-phosphate deaminase (NagB) was observed to confer enhanced tolerance to oxidative, drought, and cold stress. Consistent with this result, overproduction of GlcN by the ectopic expression of E. coli glucosamine-6-phosphate synthase (GlmS) induced cell death at an early stage. Taken together, these data suggest that genetic manipulation of endogenous GlcN level can effectively lead to the generation of abiotic stress-tolerant transgenic crop plants.

  19. Optimization of Electricity Generation Schemes in the Java-Bali Grid System with Co2 Reduction Consideration

    Directory of Open Access Journals (Sweden)

    Farizal Farizal

    2016-08-01

    Full Text Available This research considers the problem of reducing CO2 emissions from the Java-Bali power grid system that consists of a variety of power-generating plants: coal-fired, natural gas, oil, and renewable energy (PV, geothermal, hydroelectric, wind, and landfill gas. The problem is formulated as linear programming and solved using LINGO 10. The model was developed for a nation to meet a specified CO2 emission target. Two carbon dioxide mitigation options are considered in this study, i.e. fuel balancing and fuel switching. In order to reduce the CO2 emissions by 26% in 2021, State Electric Supply Company (PLN has to generate up to 30% of electricity from renewable energy (RE, and the cost of electricity (COE is expected to increase to 617.77 IDR per kWh for a fuel balancing option, while for fuel switching option, PLN has to generate 29% of electricity from RE, and the COE is expected to increase to 535.85 IDR per kWh.

  20. A Mixed Effects Randomized Item Response Model

    Science.gov (United States)

    Fox, J.-P.; Wyrick, Cheryl

    2008-01-01

    The randomized response technique ensures that individual item responses, denoted as true item responses, are randomized before observing them and so-called randomized item responses are observed. A relationship is specified between randomized item response data and true item response data. True item response data are modeled with a (non)linear…

  1. Computerized adaptive testing with item cloning

    NARCIS (Netherlands)

    Glas, Cornelis A.W.; van der Linden, Willem J.

    2003-01-01

    To increase the number of items available for adaptive testing and reduce the cost of item writing, the use of techniques of item cloning has been proposed. An important consequence of item cloning is possible variability between the item parameters. To deal with this variability, a multilevel item

  2. Increased Use of Natural Gas for Power Generation in the U.S. and the Resulting Reductions in Emissions of CO2, NOx and SO2

    Science.gov (United States)

    De Gouw, J. A.; Parrish, D. D.; Trainer, M.

    2013-12-01

    Over the past decades, natural gas has increasingly replaced coal as a fuel for electrical power generation in the U.S. As a result, there have been significant reductions in the emissions of carbon dioxide (CO2), nitrogen oxides (NOx) and sulfur dioxide (SO2). Power plant emissions are continuously measured at the stack using continuous emissions monitoring systems (CEMS) required by the EPA. Previous studies using airborne measurements have shown these CEMS measurements to be accurate. Here, we use annual emissions since 1995 from all point sources included in the CEMS database to quantify the changes in CO2, NOx and SO2 emissions that have resulted from the changing use of fuels and technologies for power generation. In 1997, 83% of electrical power in the CEMS database was generated from coal-fired power plants. In 2012, the contribution from coal had decreased to 59%, and natural gas contributed 34% of the electrical power. Natural gas-fired power plants, in particular those equipped with combined cycle technology, emit less than 50% of CO2 per kWh produced compared to coal-fired plants. As a result of the increased use of natural gas, total CO2 emissions from U.S. power plants have decreased since 2008. In addition, natural gas-fired power plants emit less NOx and far less SO2 per kWh produced than coal-fired power plants. The increased use of natural gas has therefore led to significant emissions reductions of NOx and SO2 in addition to those obtained from the implementation of emissions control systems on coal-fired power plants. The increased use of natural gas for power generation has led to significant reductions in CO2 emissions as well as improvements in U.S. air quality. We will illustrate these points with examples from airborne measurements made using the NOAA WP-3D aircraft in the Southeastern U.S. in 2013 as part of the NOAA Southeast Nexus (SENEX) study. The emissions reductions from U.S. power plants due to the increased use of natural gas will

  3. Operating Reserve Reductions from a Proposed Energy Imbalance Market with Wind and Solar Generation in the Western Interconnection

    Energy Technology Data Exchange (ETDEWEB)

    King, J.; Kirby, B.; Milligan, M.; Beuning, S.

    2012-05-01

    This paper considers several alternative forms of an energy imbalance market (EIM) proposed in the nonmarket areas of the Western Interconnection. The proposed EIM includes two changes in operating practices that independently reduce variability and increase access to responsive resources: balancing authority cooperation and sub-hourly dispatch. As the penetration of variable generation increases on the power system, additional interest in coordination would likely occur. Several alternative approaches could be used, but consideration of any form of coordinated unit commitment is beyond the scope of this analysis. This report examines the benefits of several possible EIM implementations--both separately and in concert.

  4. Item Veto: Dangerous Constitutional Tinkering.

    Science.gov (United States)

    Bellamy, Calvin

    1989-01-01

    In theory, the item veto would empower the President to remove wasteful and unnecessary projects from legislation. Yet, despite its history at the state level, the item veto is a loosely defined concept that may not work well at the federal level. Much more worrisome is the impact on the balance of power. (Author/CH)

  5. Continuous Online Item Calibration: Parameter Recovery and Item Utilization.

    Science.gov (United States)

    Ren, Hao; van der Linden, Wim J; Diao, Qi

    2017-06-01

    Parameter recovery and item utilization were investigated for different designs for online test item calibration. The design was adaptive in a double sense: it assumed both adaptive testing of examinees from an operational pool of previously calibrated items and adaptive assignment of field-test items to the examinees. Four criteria of optimality for the assignment of the field-test items were used, each of them based on the information in the posterior distributions of the examinee's ability parameter during adaptive testing as well as the sequentially updated posterior distributions of the field-test item parameters. In addition, different stopping rules based on target values for the posterior standard deviations of the field-test parameters and the size of the calibration sample were used. The impact of each of the criteria and stopping rules on the statistical efficiency of the estimates of the field-test parameters and on the time spent by the items in the calibration procedure was investigated. Recommendations as to the practical use of the designs are given.

  6. Potential Reductions in Variability with Alternative Approaches to Balancing Area Cooperation with High Penetrations of Variable Generation

    Energy Technology Data Exchange (ETDEWEB)

    Milligan, M.; Kirby, B.; Beuning, S.

    2010-08-01

    The work described in this report was performed by the National Renewable Energy Laboratory (NREL) and funded by the Office of the Energy Efficiency and Renewable Energy, U.S. Department of Energy (EERE DOE). This project is a joint project with the Pacific Northwest National Laboratory. This report evaluates the physical characteristics that improve the ability of the power system to absorb variable generation. It then uses evidence from electricity markets in the Eastern Interconnection of the United States to show how large, fast energy markets can help with integration. The concept of Virtual Balancing Area is introduced, a concept that covers a broad range of cooperative measures that can be undertaken by balancing areas to help manage variability.

  7. Potential Reductions in Variability with Alternative Approaches to Balancing Area Cooperation with High Penetrations of Variable Generation

    Energy Technology Data Exchange (ETDEWEB)

    Milligan, M.; Kirby, B.; Beuning, S.

    2010-08-01

    The work described in this report was performed by the National Renewable Energy Laboratory (NREL) and funded by the Office of the Energy Efficiency and Renewable Energy, U.S. Department of Energy (EERE DOE). This project is a joint project with the Pacific Northwest National Laboratory. This report evaluates the physical characteristics that improve the ability of the power system to absorb variable generation. It then uses evidence from electricity markets in the Eastern Interconnection of the United States to show how large, fast energy markets can help with integration. The concept of Virtual Balancing Area is introduced, a concept that covers a broad range of cooperative measures that can be undertaken by balancing areas to help manage variability.

  8. Reduction of deep levels generated by ion implantation into n- and p-type 4H-SiC

    Science.gov (United States)

    Kawahara, Koutarou; Suda, Jun; Pensl, Gerhard; Kimoto, Tsunenobu

    2010-08-01

    The authors have investigated effects of thermal oxidation on deep levels in the whole energy range of the band gap of 4H-SiC by deep level transient spectroscopy. The deep levels are generated by ion implantation. The dominant defects in n-type samples after ion implantation and high-temperature annealing at 1700 °C are IN3 (Z1/2: EC-0.63 eV) and IN9 (EH6/7: EC-1.5 eV) in low-dose-implanted samples, and IN8 (EC-1.2 eV) in high-dose-implanted samples. These defects can remarkably be reduced by thermal oxidation at 1150 °C. In p-type samples, however, IP8 (HK4: EV+1.4 eV) survives and additional defects such as IP4 (HK0: EV+0.72 eV) appear after thermal oxidation in low-dose-implanted samples. In high-dose-implanted p-type samples, three dominant levels, IP5 (HK2: EV+0.85 eV), IP6 (EV+1.0 eV), and IP7 (HK3: EV+1.3 eV), are remarkably reduced by oxidation at 1150 °C. The dominant defect IP4 observed in p-type 4H-SiC after thermal oxidation can be reduced by subsequent annealing in Ar at 1400 °C. These phenomena are explained by a model that excess interstitials are generated at the oxidizing interface, which diffuse into the bulk region.

  9. Evaluation and Reduction of Artifacts Generated by 4 Different Root-end Filling Materials by Using Multiple Cone-beam Computed Tomography Imaging Settings.

    Science.gov (United States)

    Helvacioglu-Yigit, Dilek; Demirturk Kocasarac, Husniye; Bechara, Boulos; Noujeim, Marcel

    2016-02-01

    After endodontic surgery, radiographic assessment is the method of choice to monitor bone defect healing. Cone-beam computed tomography scans are useful to check and identify the reasons of failure of surgical intervention or confirm healing; however, the artifact generated by some root-end filling material might compromise this task. The objective of the study was to compare the amount of artifacts generated by 4 root-end filling materials and to test multiple exposure settings used with these materials, when the effective dose generated by each protocol was taken into consideration. Twenty central incisors were endodontically treated with retrograde obturation by using amalgam, Biodentine, MTA, and Super-EBA (5 of each). They were placed in a skull with soft tissue simulation and scanned by using the Planmeca Promax Max with different kilovolt peaks (kVp): 66, 76, 84, and 96 with and without the use of metal artifact reduction (MAR) algorithm and with low, normal, and high resolution and high definition. The Dose Area Product was registered, and the effective dose was calculated. Amalgam generated the highest amount of artifacts, whereas MAR and low resolution created fewer artifacts than other settings. The artifacts were also reduced with 96 kVp. The effective dose calculated with low resolution was remarkably lower than other resolutions. When used as root-end filling material, Biodentine, MTA, and Super-EBA generated fewer artifacts than amalgam. The use of 96 kVp with MAR and low resolution also reduced artifacts on the image and at the same time generated the lowest effective dose. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  10. A unified view of energetic efficiency in active drag reduction, thrust generation and self-propulsion through a loss coefficient with some applications

    Science.gov (United States)

    Arakeri, Jaywant H.; Shukla, Ratnesh K.

    2013-08-01

    An analysis of the energy budget for the general case of a body translating in a stationary fluid under the action of an external force is used to define a power loss coefficient. This universal definition of power loss coefficient gives a measure of the energy lost in the wake of the translating body and, in general, is applicable to a variety of flow configurations including active drag reduction, self-propulsion and thrust generation. The utility of the power loss coefficient is demonstrated on a model bluff body flow problem concerning a two-dimensional elliptical cylinder in a uniform cross-flow. The upper and lower boundaries of the elliptic cylinder undergo continuous motion due to a prescribed reflectionally symmetric constant tangential surface velocity. It is shown that a decrease in drag resulting from an increase in the strength of tangential surface velocity leads to an initial reduction and eventual rise in the power loss coefficient. A maximum in energetic efficiency is attained for a drag reducing tangential surface velocity which minimizes the power loss coefficient. The effect of the tangential surface velocity on drag reduction and self-propulsion of both bluff and streamlined bodies is explored through a variation in the thickness ratio (ratio of the minor and major axes) of the elliptical cylinders.

  11. Assessing item fit for unidimensional item response theory models using residuals from estimated item response functions.

    Science.gov (United States)

    Haberman, Shelby J; Sinharay, Sandip; Chon, Kyong Hee

    2013-07-01

    Residual analysis (e.g. Hambleton & Swaminathan, Item response theory: principles and applications, Kluwer Academic, Boston, 1985; Hambleton, Swaminathan, & Rogers, Fundamentals of item response theory, Sage, Newbury Park, 1991) is a popular method to assess fit of item response theory (IRT) models. We suggest a form of residual analysis that may be applied to assess item fit for unidimensional IRT models. The residual analysis consists of a comparison of the maximum-likelihood estimate of the item characteristic curve with an alternative ratio estimate of the item characteristic curve. The large sample distribution of the residual is proved to be standardized normal when the IRT model fits the data. We compare the performance of our suggested residual to the standardized residual of Hambleton et al. (Fundamentals of item response theory, Sage, Newbury Park, 1991) in a detailed simulation study. We then calculate our suggested residuals using data from an operational test. The residuals appear to be useful in assessing the item fit for unidimensional IRT models.

  12. A comparison between new dentinal adhesives (fifth generation and traditional varnish in microleakage reduction of amalgam restorations in primary teeth

    Directory of Open Access Journals (Sweden)

    Mortazavi M. Associate Professor

    2003-06-01

    Full Text Available Statement of Problem: Microleakage presents the major cause for restorations failure in the oral cavity resulting in postoperative sensitivity, pulp irritation and secondary caries formation."nAim: The aim of this study was to compare two dentinal adhesive systems of fifth generation and copalite varnish in reducing microleakage of amalgam restorations in primary teeth."nMaterials and Methods: In this in-vitro study, 100 class V amalgam restorations were prepared on the buccal or lingual surfaces of primary molar and canine teeth. Samples were randomly divided into four groups (25 samples each. No liner was used for the first group and the second group restorations were lined with copalite varnish. Two dentin adhesives, called Syntac C and Single Bond, were used for the third and fourth groups, respectively. At the next stage, the samples were immersed in 5% fuschin solution for 24 hours, then sectioned buccolingually, and examined under a stereomicroscope for microleakage evaluation."nResults: There was a significant difference between four groups statistically (PO.000I, Comparing"nfour groups, the first and fourth ones, demonstrated the most and the least microleakage, respectively."nConclusion: The present study showed that new dentinal adhesive systems caused microleakage"nreduction in amalgam restorations of primary teeth.

  13. Bridging Income Generation with Group Integrated Care for cardiovascular risk reduction: Rationale and design of the BIGPIC study.

    Science.gov (United States)

    Vedanthan, Rajesh; Kamano, Jemima H; Lee, Hana; Andama, Benjamin; Bloomfield, Gerald S; DeLong, Allison K; Edelman, David; Finkelstein, Eric A; Hogan, Joseph W; Horowitz, Carol R; Manyara, Simon; Menya, Diana; Naanyu, Violet; Pastakia, Sonak D; Valente, Thomas W; Wanyonyi, Cleophas C; Fuster, Valentin

    2017-06-01

    Cardiovascular disease (CVD) is the leading cause of mortality worldwide, with >80% of CVD deaths occurring in low and middle income countries (LMICs). Diabetes mellitus and pre-diabetes are risk factors for CVD, and CVD is the major cause of morbidity and mortality among individuals with DM. There is a critical period now during which reducing CVD risk among individuals with diabetes and pre-diabetes may have a major impact. Cost-effective, culturally appropriate, and context-specific approaches are required. Two promising strategies to improve health outcomes are group medical visits and microfinance. This study tests whether group medical visits integrated into microfinance groups are effective and cost-effective in reducing CVD risk among individuals with diabetes or at increased risk for diabetes in western Kenya. An initial phase of qualitative inquiry will assess contextual factors, facilitators, and barriers that may impact integration of group medical visits and microfinance for CVD risk reduction. Subsequently, we will conduct a four-arm cluster randomized trial comparing: (1) usual clinical care, (2) usual clinical care plus microfinance groups only, (3) group medical visits only, and (4) group medical visits integrated into microfinance groups. The primary outcome measure will be 1-year change in systolic blood pressure, and a key secondary outcome measure is 1-year change in overall CVD risk as measured by the QRISK2 score. We will conduct mediation analysis to evaluate the influence of changes in social network characteristics on intervention outcomes, as well as moderation analysis to evaluate the influence of baseline social network characteristics on effectiveness of the interventions. Cost-effectiveness analysis will be conducted in terms of cost per unit change in systolic blood pressure, percent change in CVD risk score, and per disability-adjusted life year saved. This study will provide evidence regarding effectiveness and cost

  14. Cytotoxicity of citral against melanoma cells: The involvement of oxidative stress generation and cell growth protein reduction.

    Science.gov (United States)

    Sanches, Larissa Juliani; Marinello, Poliana Camila; Panis, Carolina; Fagundes, Tatiane Renata; Morgado-Díaz, José Andrés; de-Freitas-Junior, Julio Cesar Madureira; Cecchini, Rubens; Cecchini, Alessandra Lourenço; Luiz, Rodrigo Cabral

    2017-03-01

    Citral is a natural compound that has shown cytotoxic and antiproliferative effects on breast and hematopoietic cancer cells; however, there are few studies on melanoma cells. Oxidative stress is known to be involved in all stages of melanoma development and is able to modulate intracellular pathways related to cellular proliferation and death. In this study, we hypothesize that citral exerts its cytotoxic effect on melanoma cells by the modulation of cellular oxidative status and/or intracellular signaling. To test this hypothesis, we investigated the antiproliferative and cytotoxic effects of citral on B16F10 murine melanoma cells evaluating its effects on cellular oxidative stress, DNA damage, cell death, and important signaling pathways, as these pathways, namely, extracellular signal-regulated kinases 1/2 (ERK1/2), AKT, and phosphatidylinositol-3 kinase, are involved in cell proliferation and differentiation. The p53 and nuclear factor kappa B were also investigated due to their ability to respond to intracellular stress. We observed that citral exerted antiproliferative and cytotoxic effects in B16F10; induced oxidative stress, DNA lesions, and p53 nuclear translocation; and reduced nitric oxide levels and nuclear factor kappa B, ERK1/2, and AKT. To investigate citral specificity, we used non-neoplastic human and murine cells, HaCaT (human skin keratinocytes) and NIH-3T3 cells (murine fibroblasts), and observed that although citral effects were not specific for cancer cells, non-neoplastic cells were more resistant to citral than B16F10. These findings highlight the potential clinical utility of citral in melanoma, with a mechanism of action involving the oxidative stress generation, nitric oxide depletion, and interference in signaling pathways related to cell proliferation.

  15. Global positive polarity items and obligatory exhaustivity

    Directory of Open Access Journals (Sweden)

    Benjamin Spector

    2014-11-01

    Full Text Available I argue for a distinction between two types of positive polarity items (PPIs which has not been recognized so far. While for some PPIs, anti-licensing is a strictly local phenomenon, for other PPIs anti-licensing should be stated as a global condition. I aim to contribute to a principled explanation for the distribution of a significant subset of global PPIs, by relating it to specific semantic properties of the relevant items. More specifically, I argue that PPIs such as soit ... soit ..., quelques and almost trigger obligatory exhaustivity effects and scalar inferences, and that independently motivated constraints regarding the generation of such inferences can account for their distribution. The paper also briefly addresses the case of other global PPIs, e.g., at least, for which a similar account is not straightforwardly available. http://dx.doi.org/10.3765/sp.7.11 BibTeX info

  16. Cyanide oxidation by singlet oxygen generated via reaction between H2O2 from cathodic reduction and OCl(-) from anodic oxidation.

    Science.gov (United States)

    Tian, Shichao; Li, Yibing; Zeng, Huabin; Guan, Wei; Wang, Yan; Zhao, Xu

    2016-11-15

    Cyanide is widely present in electroplating wastewater or metallurgical effluents. In the present study, the electrochemical destruction of cyanide with various anode and cathode compositions under alkaline conditions was investigated. The results indicated that the electrochemical system using RuO2/Ti as anode and activated carbon fiber (ACF) as cathode in the presence of sodium chloride was efficient for the cyanide removal. In this system, in situ generation of HClO by anodic oxidation of Cl(-) at RuO2/Ti anode occurred with the H2O2 generation by O2 reduction at ACF cathode. As confirmed by the electron spin resonance technique, the reaction between HClO and H2O2 led to the generation of singlet oxygen, which was responsible for the cyanide removal. Further experiment indicated that the cyanide removal efficiency increased with the increase of the current density or the sodium chloride concentration. Cyanate was identified as main product in the system. Besides, the system exhibited good stability for the cyanide removal, which was beneficial to its practical application.

  17. Development of a lack of appetite item bank for computer-adaptive testing (CAT)

    DEFF Research Database (Denmark)

    Thamsborg, Lise Laurberg Holst; Petersen, Morten Aa; Aaronson, Neil K

    2015-01-01

    measurement precision. The EORTC Quality of Life Group is developing a CAT version of the widely used EORTC QLQ-C30 questionnaire. Here, we report on the development of the lack of appetite CAT. METHODS: The EORTC approach to CAT development comprises four phases: literature search, operationalization, pre......-testing, and field testing. Phases 1-3 are described in this paper. First, a list of items was retrieved from the literature. This was refined, deleting redundant and irrelevant items. Next, new items fitting the "QLQ-C30 item style" were created. These were evaluated by international samples of experts and cancer...... to 12 lack of appetite items. CONCLUSIONS: Phases 1-3 resulted in 12 lack of appetite candidate items. Based on a field testing (phase 4), the psychometric characteristics of the items will be assessed and the final item bank will be generated. This CAT item bank is expected to provide precise...

  18. Counting Frequencies from Zotero Items

    Directory of Open Access Journals (Sweden)

    Spencer Roberts

    2013-04-01

    Full Text Available In Counting Frequencies you learned how to count the frequency of specific words in a list using python. In this lesson, we will expand on that topic by showing you how to get information from Zotero HTML items, save the content from those items, and count the frequencies of words. It may be beneficial to look over the previous lesson before we begin.

  19. Multilevel Modeling of Item Position Effects

    Science.gov (United States)

    Albano, Anthony D.

    2013-01-01

    In many testing programs it is assumed that the context or position in which an item is administered does not have a differential effect on examinee responses to the item. Violations of this assumption may bias item response theory estimates of item and person parameters. This study examines the potentially biasing effects of item position. A…

  20. Effects of Reducing the Cognitive Load of Mathematics Test Items on Student Performance

    Directory of Open Access Journals (Sweden)

    Susan C. Gillmor

    2015-01-01

    Full Text Available This study explores a new item-writing framework for improving the validity of math assessment items. The authors transfer insights from Cognitive Load Theory (CLT, traditionally used in instructional design, to educational measurement. Fifteen, multiple-choice math assessment items were modified using research-based strategies for reducing extraneous cognitive load. An experimental design with 222 middle-school students tested the effects of the reduced cognitive load items on student performance and anxiety. Significant findings confirm the main research hypothesis that reducing the cognitive load of math assessment items improves student performance. Three load-reducing item modifications are identified as particularly effective for reducing item difficulty: signalling important information, aesthetic item organization, and removing extraneous content. Load reduction was not shown to impact student anxiety. Implications for classroom assessment and future research are discussed.

  1. Guiding Surge Reduction Strategies via Characterization of Coastal Surge Propagation and Internal Surge Generation within a Complex Bay/Estuary System, Galveston Bay, TX

    Science.gov (United States)

    Bass, B.; Torres, J.; Irza, N.; Bedient, P. B.; Dawson, C.; Proft, J.

    2015-12-01

    In this study, Hurricane Ike (2008) and a suite of synthetic storms are simulated in order to evaluate how different hurricane landfalls, wind intensities, and radius to maximum winds influence the surge response in complex semi-enclosed bays such as Galveston Bay, located along the Texas Gulf Coast. The Advanced CIRCulation and Simulating Waves Nearshore (ADCIRC+SWAN) models are employed to quantify surge in terms of its relative coastal contributions that propagate across barrier islands and tidal inlets and subsequently into Galveston Bay, the surge generated locally within the Bay itself, and the interaction between these coastal and local components of surge. Results from this research will further the current understanding of surge interactions in bay systems and guide coastal engineering surge reduction projects that need to consider multiple lines of defense to protect complex bay/estuary systems such as Galveston Bay, TX.

  2. Using Next-Generation Sequencing to Contrast the Diet and Explore Pest-Reduction Services of Sympatric Bird Species in Macadamia Orchards in Australia.

    Science.gov (United States)

    Crisol-Martínez, Eduardo; Moreno-Moyano, Laura T; Wormington, Kevin R; Brown, Philip H; Stanley, Dragana

    2016-01-01

    Worldwide, avian communities inhabiting agro-ecosystems are threatened as a consequence of agricultural intensification. Unravelling their ecological role is essential to focus conservation efforts. Dietary analysis can elucidate bird-insect interactions and expose avian pest-reduction services, thus supporting avian conservation. In this study, we used next-generation sequencing to analyse the dietary arthropod contents of 11 sympatric bird species foraging in macadamia orchards in eastern Australia. Across all species and based on arthropod DNA sequence similarities ≥98% with records in the Barcode of Life Database, 257 operational taxonomy units were assigned to 8 orders, 40 families, 90 genera and 89 species. These taxa included 15 insect pests, 5 of which were macadamia pests. Among the latter group, Nezara viridula (Pentatomidae; green vegetable bug), considered a major pest, was present in 23% of all faecal samples collected. Results also showed that resource partitioning in this system is low, as most bird species shared large proportion of their diets by feeding primarily on lepidopteran, dipteran and arachnids. Dietary composition differed between some species, most likely because of differences in foraging behaviour. Overall, this study reached a level of taxonomic resolution never achieved before in the studied species, thus contributing to a significant improvement in the avian ecological knowledge. Our results showed that bird communities prey upon economically important pests in macadamia orchards. This study set a precedent by exploring avian pest-reduction services using next-generation sequencing, which could contribute to the conservation of avian communities and their natural habitats in agricultural systems.

  3. Using Next-Generation Sequencing to Contrast the Diet and Explore Pest-Reduction Services of Sympatric Bird Species in Macadamia Orchards in Australia.

    Directory of Open Access Journals (Sweden)

    Eduardo Crisol-Martínez

    Full Text Available Worldwide, avian communities inhabiting agro-ecosystems are threatened as a consequence of agricultural intensification. Unravelling their ecological role is essential to focus conservation efforts. Dietary analysis can elucidate bird-insect interactions and expose avian pest-reduction services, thus supporting avian conservation. In this study, we used next-generation sequencing to analyse the dietary arthropod contents of 11 sympatric bird species foraging in macadamia orchards in eastern Australia. Across all species and based on arthropod DNA sequence similarities ≥98% with records in the Barcode of Life Database, 257 operational taxonomy units were assigned to 8 orders, 40 families, 90 genera and 89 species. These taxa included 15 insect pests, 5 of which were macadamia pests. Among the latter group, Nezara viridula (Pentatomidae; green vegetable bug, considered a major pest, was present in 23% of all faecal samples collected. Results also showed that resource partitioning in this system is low, as most bird species shared large proportion of their diets by feeding primarily on lepidopteran, dipteran and arachnids. Dietary composition differed between some species, most likely because of differences in foraging behaviour. Overall, this study reached a level of taxonomic resolution never achieved before in the studied species, thus contributing to a significant improvement in the avian ecological knowledge. Our results showed that bird communities prey upon economically important pests in macadamia orchards. This study set a precedent by exploring avian pest-reduction services using next-generation sequencing, which could contribute to the conservation of avian communities and their natural habitats in agricultural systems.

  4. Archaeal community structure in leachate and solid waste is correlated to methane generation and volume reduction during biodegradation of municipal solid waste.

    Science.gov (United States)

    Fei, Xunchang; Zekkos, Dimitrios; Raskin, Lutgarde

    2015-02-01

    Duplicate carefully-characterized municipal solid waste (MSW) specimens were reconstituted with waste constituents obtained from a MSW landfill and biodegraded in large-scale landfill simulators for about a year. Repeatability and relationships between changes in physical, chemical, and microbial characteristics taking place during the biodegradation process were evaluated. Parameters such as rate of change of soluble chemical oxygen demand in the leachate (rsCOD), rate of methane generation (rCH4), rate of specimen volume reduction (rVt), DNA concentration in the leachate, and archaeal community structures in the leachate and solid waste were monitored during operation. The DNA concentration in the leachate was correlated to rCH4 and rVt. The rCH4 was related to rsCOD and rVt when waste biodegradation was intensive. The structures of archaeal communities in the leachate and solid waste of both simulators were very similar and Methanobacteriaceae were the dominant archaeal family throughout the testing period. Monitoring the chemical and microbial characteristics of the leachate was informative of the biodegradation process and volume reduction in the simulators, suggesting that leachate monitoring could be informative of the extent of biodegradation in a full-scale landfill.

  5. Uranium recovering from slags generated in the metallic uranium by magnesiothermic reduction; Recuperacao de uranio em escorias geradas na producao de uranio metalico por magnesiotermia

    Energy Technology Data Exchange (ETDEWEB)

    Fornarolo, F.; Carvalho, E.F. Urano de; Durazzo, M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro do Combustivel Nuclear], e-mail: jbsneto@ipen.br; Riella, H.G. [Universidade Federal de Santa Catarina (UFSC), Florianopolis (Brazil). Dept. de Engenharia Quimica

    2008-11-15

    The Nuclear Fuel Center of IPEN/CNEN-SP has recent/y concluded a program for developing the fabrication technology of the nuclear fuel based on the U{sub 3}Si{sub 2}-Al dispersion, which is being used in the IEA-R1 research reactor. The uranium silicide (U{sub 3}Si{sub 2}) fuel production starts with the uranium hexafluoride (UF{sub 6}) processing and uranium tetrafluoride (UF{sub 4}) precipitation. Then, the UF{sub 4} is converted to metallic uranium by magnesiothermic reduction. The UF{sub 4} reduction by magnesium generates MgF{sub 2} slag containing considerable concentrations of uranium, which could reach 20 wt%. The uranium contained in that slag should be recovered and this work presents the results obtained in recovering the uranium from that slag. The uranium recovery is accomplished by acidic leaching of the calcined slag. The calcination transforms the metallic uranium in U{sub 3}O{sub 8}, promoting the pulverization of the pieces of metallic uranium and facilitating the leaching operation. As process variables, have been considered the nitric molar concentration, the acid excess regarding the stoichiometry and the leaching temperature. As result, the uranium recovery reached a 96% yield. (author)

  6. Reduction of the THG emissions in agricultural productions for the generation of biofuels; Senkung der THG-Emissionen in landwirtschaftlichen Produktionsverfahren zur Erzeugung von Biokraftstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Schiemenz, Katja; Gurgel, Andreas [Landesforschungsanstalt fuer Landwirtschaft und Fischerei Mecklenburg-Vorpommern, Guelzow-Pruezen (Germany). Inst. fuer Pflanzenproduktion und Betriebswirtschaft

    2013-10-01

    The Renewable Energy Directive (RED, 2009/128/EC) sets a binding goal of substituting at least 10% of fossil fuel consumption with renewable energy from 2020 onwards. Although biofuels of the second generation promise ecological and economic advantages, they are not yet available or (as with biomethane) available only to a very limited extent. It is therefore important to produce the currently available biofuels in a more environmentally friendly manner, particularly as biofuels must show a reduction in greenhouse gas (GHG) emissions relative to the fossil fuels they replace of 50% by 2017 and 60% by 2018 as per the German Biofuel Sustainability Ordinance. This concerns emissions from the whole biofuel production chain. In energy crop production the level of GHG emissions is particularly dependent on the amount of N fertilization and the intensity of soil tillage as well as indirectly on the amount of diesel consumption. A current LFA research project aims at the reduction of GHG field emissions in cultivation systems with energy crops (rape, ethanol wheat) for biofuel production. For this, the opportunities which arise from the use of crop rotation with multiple crop types appropriate for the location with the inclusion of N-fixing grain legumes and production technology should be grasped. (orig.)

  7. Australian Item Bank Program: Social Science Item Bank.

    Science.gov (United States)

    Australian Council for Educational Research, Hawthorn.

    After vigorous review, editing, and trial testing, this item bank was compiled to help secondary school teachers construct objective tests in the social sciences. Anthropology, economics, ethnic and cultural studies, geography, history, legal studies, politics, and sociology are among the topics represented. The bank consists of multiple choice…

  8. Modelling sequentially scored item responses

    NARCIS (Netherlands)

    Akkermans, W.

    2000-01-01

    The sequential model can be used to describe the variable resulting from a sequential scoring process. In this paper two more item response models are investigated with respect to their suitability for sequential scoring: the partial credit model and the graded response model. The investigation is c

  9. Psychometric Consequences of Subpopulation Item Parameter Drift

    Science.gov (United States)

    Huggins-Manley, Anne Corinne

    2017-01-01

    This study defines subpopulation item parameter drift (SIPD) as a change in item parameters over time that is dependent on subpopulations of examinees, and hypothesizes that the presence of SIPD in anchor items is associated with bias and/or lack of invariance in three psychometric outcomes. Results show that SIPD in anchor items is associated…

  10. Psychometric Consequences of Subpopulation Item Parameter Drift

    Science.gov (United States)

    Huggins-Manley, Anne Corinne

    2017-01-01

    This study defines subpopulation item parameter drift (SIPD) as a change in item parameters over time that is dependent on subpopulations of examinees, and hypothesizes that the presence of SIPD in anchor items is associated with bias and/or lack of invariance in three psychometric outcomes. Results show that SIPD in anchor items is associated…

  11. Unidimensional Interpretations for Multidimensional Test Items

    Science.gov (United States)

    Kahraman, Nilufer

    2013-01-01

    This article considers potential problems that can arise in estimating a unidimensional item response theory (IRT) model when some test items are multidimensional (i.e., show a complex factorial structure). More specifically, this study examines (1) the consequences of model misfit on IRT item parameter estimates due to unintended minor item-level…

  12. Generalizability theory and item response theory

    NARCIS (Netherlands)

    Glas, Cornelis A.W.; Eggen, T.J.H.M.; Veldkamp, B.P.

    2012-01-01

    Item response theory is usually applied to items with a selected-response format, such as multiple choice items, whereas generalizability theory is usually applied to constructed-response tasks assessed by raters. However, in many situations, raters may use rating scales consisting of items with a

  13. Generalizability theory and item response theory

    NARCIS (Netherlands)

    Glas, C.A.W.; Eggen, T.J.H.M.; Veldkamp, B.P.

    2012-01-01

    Item response theory is usually applied to items with a selected-response format, such as multiple choice items, whereas generalizability theory is usually applied to constructed-response tasks assessed by raters. However, in many situations, raters may use rating scales consisting of items with a s

  14. 15 CFR 742.15 - Encryption items.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Encryption items. 742.15 Section 742... BASED CONTROLS § 742.15 Encryption items. Encryption items can be used to maintain the secrecy of... export and reexport of encryption items. As the President indicated in Executive Order 13026 and in his...

  15. Item-Writing Guidelines for Physics

    Science.gov (United States)

    Regan, Tom

    2015-01-01

    A teacher learning how to write test questions (test items) will almost certainly encounter item-writing guidelines--lists of item-writing do's and don'ts. Item-writing guidelines usually are presented as applicable across all assessment settings. Table I shows some guidelines that I believe to be generally applicable and two will be briefly…

  16. Unidimensional Interpretations for Multidimensional Test Items

    Science.gov (United States)

    Kahraman, Nilufer

    2013-01-01

    This article considers potential problems that can arise in estimating a unidimensional item response theory (IRT) model when some test items are multidimensional (i.e., show a complex factorial structure). More specifically, this study examines (1) the consequences of model misfit on IRT item parameter estimates due to unintended minor item-level…

  17. Central receiver solar thermal power system, Phase 1. CDRL item 2. Pilot plant preliminary design report. Volume VI. Electrical power generation and master control subsystems and balance of plant

    Energy Technology Data Exchange (ETDEWEB)

    Hallet, Jr., R. W.; Gervais, R. L.

    1977-10-01

    The requirements, performance, and subsystem configuration for both the Commercial and Pilot Plant electrical power generation subsystems (EPGS) and balance of plants are presented. The EPGS for both the Commercial Plant and Pilot Plant make use of conventional, proven equipment consistent with good power plant design practices in order to minimize risk and maximize reliability. The basic EPGS cycle selected is a regenerative cycle that uses a single automatic admission, condensing, tandem-compound double-flow turbine. Specifications, performance data, drawings, and schematics are included. (WHK)

  18. The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value.

    Science.gov (United States)

    Rush, Bonnie R; Rankin, David C; White, Brad J

    2016-09-29

    Failure to adhere to standard item-writing guidelines may render examination questions easier or more difficult than intended. Item complexity describes the cognitive skill level required to obtain a correct answer. Higher cognitive examination items promote critical thinking and are recommended to prepare students for clinical training. This study evaluated faculty-authored examinations to determine the impact of item-writing flaws and item complexity on the difficulty and discrimination value of examination items used to assess third year veterinary students. The impact of item-writing flaws and item complexity (cognitive level I-V) on examination item difficulty and discrimination value was evaluated on 1925 examination items prepared by clinical faculty for third year veterinary students. The mean (± SE) percent correct (83.3 % ± 17.5) was consistent with target values in professional education, and the mean discrimination index (0.18 ± 0.17) was slightly lower than recommended (0.20). More than one item-writing flaw was identified in 37.3 % of questions. The most common item-writing flaws were awkward stem structure, implausible distractors, longest response is correct, and responses are series of true-false statements. Higher cognitive skills (complexity level III-IV) were required to correctly answer 38.4 % of examination items. As item complexity increased, item difficulty and discrimination values increased. The probability of writing discriminating, difficult examination items decreased when implausible distractors and all of the above were used, and increased if the distractors were comprised of a series of true/false statements. Items with four distractors were not more difficult or discriminating than items with three distractors. Preparation of examination questions targeting higher cognitive levels will increase the likelihood of constructing discriminating items. Use of implausible distractors to complete a five-option multiple choice

  19. Frequent item sets mining from high-dimensional dataset based on a novel binary particle swarm optimization

    Institute of Scientific and Technical Information of China (English)

    张中杰; 黄健; 卫莹

    2016-01-01

    A novel binary particle swarm optimization for frequent item sets mining from high-dimensional dataset (BPSO-HD) was proposed, where two improvements were joined. Firstly, the dimensionality reduction of initial particles was designed to ensure the reasonable initial fitness, and then, the dynamically dimensionality cutting of dataset was built to decrease the search space. Based on four high-dimensional datasets, BPSO-HD was compared with Apriori to test its reliability, and was compared with the ordinary BPSO and quantum swarm evolutionary (QSE) to prove its advantages. The experiments show that the results given by BPSO-HD is reliable and better than the results generated by BPSO and QSE.

  20. Logistics Reduction and Repurposing Technology for Long Duration Space Missions

    Science.gov (United States)

    Broyan, James Lee, Jr.; Chu, Andrew; Ewert, Michael K.

    2014-01-01

    One of NASA's Advanced Exploration Systems (AES) projects is the Logistics Reduction and Repurposing (LRR) project, which has the goal of reducing logistics resupply items through direct and indirect means. Various technologies under development in the project will reduce the launch mass of consumables and their packaging, enable reuse and repurposing of items, and make logistics tracking more efficient. Repurposing also reduces the trash burden onboard spacecraft and indirectly reduces launch mass by one manifest item having two purposes rather than two manifest items each having only one purpose. This paper provides the status of each of the LRR technologies in their third year of development under AES. Advanced clothing systems (ACSs) are being developed to enable clothing to be worn longer, directly reducing launch mass. ACS has completed a ground exercise clothing study in preparation for an International Space Station technology demonstration in 2014. Development of launch packaging containers and other items that can be repurposed on-orbit as part of habitation outfitting has resulted in a logistics-to-living (L2L) concept. L2L has fabricated and evaluated several multi-purpose cargo transfer bags for potential reuse on-orbit. Autonomous logistics management is using radio frequency identification (RFID) to track items and thus reduce crew time for logistics functions. An RFID dense reader prototype is under construction and plans for integrated testing are being made. A heat melt compactor (HMC) second generation unit for processing trash into compact and stable tiles is nearing completion. The HMC prototype compaction chamber has been completed and system development testing is under way. Research has been conducted on the conversion of trash-to-gas (TtG) for high levels of volume reduction and for use in propulsion systems. A steam reformation system was selected for further system definition of the TtG technology.

  1. Identifying predictors of physics item difficulty: A linear regression approach

    Directory of Open Access Journals (Sweden)

    Vanes Mesic

    2011-06-01

    Full Text Available Large-scale assessments of student achievement in physics are often approached with an intention to discriminate students based on the attained level of their physics competencies. Therefore, for purposes of test design, it is important that items display an acceptable discriminatory behavior. To that end, it is recommended to avoid extraordinary difficult and very easy items. Knowing the factors that influence physics item difficulty makes it possible to model the item difficulty even before the first pilot study is conducted. Thus, by identifying predictors of physics item difficulty, we can improve the test-design process. Furthermore, we get additional qualitative feedback regarding the basic aspects of student cognitive achievement in physics that are directly responsible for the obtained, quantitative test results. In this study, we conducted a secondary analysis of data that came from two large-scale assessments of student physics achievement at the end of compulsory education in Bosnia and Herzegovina. Foremost, we explored the concept of “physics competence” and performed a content analysis of 123 physics items that were included within the above-mentioned assessments. Thereafter, an item database was created. Items were described by variables which reflect some basic cognitive aspects of physics competence. For each of the assessments, Rasch item difficulties were calculated in separate analyses. In order to make the item difficulties from different assessments comparable, a virtual test equating procedure had to be implemented. Finally, a regression model of physics item difficulty was created. It has been shown that 61.2% of item difficulty variance can be explained by factors which reflect the automaticity, complexity, and modality of the knowledge structure that is relevant for generating the most probable correct solution, as well as by the divergence of required thinking and interference effects between intuitive and formal

  2. Identifying predictors of physics item difficulty: A linear regression approach

    Science.gov (United States)

    Mesic, Vanes; Muratovic, Hasnija

    2011-06-01

    Large-scale assessments of student achievement in physics are often approached with an intention to discriminate students based on the attained level of their physics competencies. Therefore, for purposes of test design, it is important that items display an acceptable discriminatory behavior. To that end, it is recommended to avoid extraordinary difficult and very easy items. Knowing the factors that influence physics item difficulty makes it possible to model the item difficulty even before the first pilot study is conducted. Thus, by identifying predictors of physics item difficulty, we can improve the test-design process. Furthermore, we get additional qualitative feedback regarding the basic aspects of student cognitive achievement in physics that are directly responsible for the obtained, quantitative test results. In this study, we conducted a secondary analysis of data that came from two large-scale assessments of student physics achievement at the end of compulsory education in Bosnia and Herzegovina. Foremost, we explored the concept of “physics competence” and performed a content analysis of 123 physics items that were included within the above-mentioned assessments. Thereafter, an item database was created. Items were described by variables which reflect some basic cognitive aspects of physics competence. For each of the assessments, Rasch item difficulties were calculated in separate analyses. In order to make the item difficulties from different assessments comparable, a virtual test equating procedure had to be implemented. Finally, a regression model of physics item difficulty was created. It has been shown that 61.2% of item difficulty variance can be explained by factors which reflect the automaticity, complexity, and modality of the knowledge structure that is relevant for generating the most probable correct solution, as well as by the divergence of required thinking and interference effects between intuitive and formal physics knowledge

  3. MOF catalysis of Fe(II)-to-Fe(III) reaction for an ultrafast and one-step generation of the Fe2O3@MOF composite and uranium(vi) reduction by iron(ii) under ambient conditions.

    Science.gov (United States)

    Xiong, Yang Yang; Li, Jian Qiang; Yan, Chang Sheng; Gao, Heng Ya; Zhou, Jian Ping; Gong, Le Le; Luo, Ming Biao; Zhang, Le; Meng, Pan Pan; Luo, Feng

    2016-08-07

    Herein, we demonstrate that Zn-MOF-74 enables the ultrafast and one-step generation of the Fe2O3@MOF composite once Zn-MOF-74 contacts with FeSO4 solution. This unique reaction can be further applied in catalysis of U(vi) reduction by Fe(ii) under ambient conditions. The results provide a highly renovated strategy for U(vi) reduction by Fe(ii) just under ambient conditions, which completely subvert all established methods about U(vi) reduction by Fe(ii) in which O2- and CO2-free conditions are absolutely required.

  4. Analysis of differential item functioning in the depression item bank from the Patient Reported Outcome Measurement Information System (PROMIS: An item response theory approach

    Directory of Open Access Journals (Sweden)

    JOSEPH P. EIMICKE

    2009-06-01

    Full Text Available The aims of this paper are to present findings related to differential item functioning (DIF in the Patient Reported Outcome Measurement Information System (PROMIS depression item bank, and to discuss potential threats to the validity of results from studies of DIF. The 32 depression items studied were modified from several widely used instruments. DIF analyses of gender, age and education were performed using a sample of 735 individuals recruited by a survey polling firm. DIF hypotheses were generated by asking content experts to indicate whether or not they expected DIF to be present, and the direction of the DIF with respect to the studied comparison groups. Primary analyses were conducted using the graded item response model (for polytomous, ordered response category data with likelihood ratio tests of DIF, accompanied by magnitude measures. Sensitivity analyses were performed using other item response models and approaches to DIF detection. Despite some caveats, the items that are recommended for exclusion or for separate calibration were "I felt like crying" and "I had trouble enjoying things that I used to enjoy." The item, "I felt I had no energy," was also flagged as evidencing DIF, and recommended for additional review. On the one hand, false DIF detection (Type 1 error was controlled to the extent possible by ensuring model fit and purification. On the other hand, power for DIF detection might have been compromised by several factors, including sparse data and small sample sizes. Nonetheless, practical and not just statistical significance should be considered. In this case the overall magnitude and impact of DIF was small for the groups studied, although impact was relatively large for some individuals.

  5. Analysis of differential item functioning in the depression item bank from the Patient Reported Outcome Measurement Information System (PROMIS): An item response theory approach

    Science.gov (United States)

    Teresi, Jeanne A.; Ocepek-Welikson, Katja; Kleinman, Marjorie; Eimicke, Joseph P.; Crane, Paul K.; Jones, Richard N.; Lai, Jin-shei; Choi, Seung W.; Hays, Ron D.; Reeve, Bryce B.; Reise, Steven P.; Pilkonis, Paul A.; Cella, David

    2009-01-01

    The aims of this paper are to present findings related to differential item functioning (DIF) in the Patient Reported Outcome Measurement Information System (PROMIS) depression item bank, and to discuss potential threats to the validity of results from studies of DIF. The 32 depression items studied were modified from several widely used instruments. DIF analyses of gender, age and education were performed using a sample of 735 individuals recruited by a survey polling firm. DIF hypotheses were generated by asking content experts to indicate whether or not they expected DIF to be present, and the direction of the DIF with respect to the studied comparison groups. Primary analyses were conducted using the graded item response model (for polytomous, ordered response category data) with likelihood ratio tests of DIF, accompanied by magnitude measures. Sensitivity analyses were performed using other item response models and approaches to DIF detection. Despite some caveats, the items that are recommended for exclusion or for separate calibration were “I felt like crying” and “I had trouble enjoying things that I used to enjoy.” The item, “I felt I had no energy,” was also flagged as evidencing DIF, and recommended for additional review. On the one hand, false DIF detection (Type 1 error) was controlled to the extent possible by ensuring model fit and purification. On the other hand, power for DIF detection might have been compromised by several factors, including sparse data and small sample sizes. Nonetheless, practical and not just statistical significance should be considered. In this case the overall magnitude and impact of DIF was small for the groups studied, although impact was relatively large for some individuals. PMID:20336180

  6. Understanding and quantifying cognitive complexity level in mathematical problem solving items

    Directory of Open Access Journals (Sweden)

    SUSAN E. EMBRETSON

    2008-09-01

    Full Text Available The linear logistic test model (LLTM; Fischer, 1973 has been applied to a wide variety of new tests. When the LLTM application involves item complexity variables that are both theoretically interesting and empirically supported, several advantages can result. These advantages include elaborating construct validity at the item level, defining variables for test design, predicting parameters of new items, item banking by sources of complexity and providing a basis for item design and item generation. However, despite the many advantages of applying LLTM to test items, it has been applied less often to understand the sources of complexity for large-scale operational test items. Instead, previously calibrated item parameters are modeled using regression techniques because raw item response data often cannot be made available. In the current study, both LLTM and regression modeling are applied to mathematical problem solving items from a widely used test. The findings from the two methods are compared and contrasted for their implications for continued development of ability and achievement tests based on mathematical problem solving items.

  7. Teoria da Resposta ao Item Teoria de la respuesta al item Item response theory

    Directory of Open Access Journals (Sweden)

    Eutalia Aparecida Candido de Araujo

    2009-12-01

    Full Text Available A preocupação com medidas de traços psicológicos é antiga, sendo que muitos estudos e propostas de métodos foram desenvolvidos no sentido de alcançar este objetivo. Entre os trabalhos propostos, destaca-se a Teoria da Resposta ao Item (TRI que, a princípio, veio completar limitações da Teoria Clássica de Medidas, empregada em larga escala até hoje na medida de traços psicológicos. O ponto principal da TRI é que ela leva em consideração o item particularmente, sem relevar os escores totais; portanto, as conclusões não dependem apenas do teste ou questionário, mas de cada item que o compõe. Este artigo propõe-se a apresentar esta Teoria que revolucionou a teoria de medidas.La preocupación con las medidas de los rasgos psicológicos es antigua y muchos estudios y propuestas de métodos fueron desarrollados para lograr este objetivo. Entre estas propuestas de trabajo se incluye la Teoría de la Respuesta al Ítem (TRI que, en principio, vino a completar las limitaciones de la Teoría Clásica de los Tests, ampliamente utilizada hasta hoy en la medida de los rasgos psicológicos. El punto principal de la TRI es que se tiene en cuenta el punto concreto, sin relevar las puntuaciones totales; por lo tanto, los resultados no sólo dependen de la prueba o cuestionario, sino que de cada ítem que lo compone. En este artículo se propone presentar la Teoría que revolucionó la teoría de medidas.The concern with measures of psychological traits is old and many studies and proposals of methods were developed to achieve this goal. Among these proposed methods highlights the Item Response Theory (IRT that, in principle, came to complete limitations of the Classical Test Theory, which is widely used until nowadays in the measurement of psychological traits. The main point of IRT is that it takes into account the item in particular, not relieving the total scores; therefore, the findings do not only depend on the test or questionnaire

  8. Unfair items detection in educational measurement

    CERN Document Server

    Bakman, Yefim

    2012-01-01

    Measurement professionals cannot come to an agreement on the definition of the term 'item fairness'. In this paper a continuous measure of item unfairness is proposed. The more the unfairness measure deviates from zero, the less fair the item is. If the measure exceeds the cutoff value, the item is identified as definitely unfair. The new approach can identify unfair items that would not be identified with conventional procedures. The results are in accord with experts' judgments on the item qualities. Since no assumptions about scores distributions and/or correlations are assumed, the method is applicable to any educational test. Its performance is illustrated through application to scores of a real test.

  9. The 40 anniversary of the 1976 Friuli earthquake: a look back for empowering the next generation to the reduction of seismic risk

    Science.gov (United States)

    Saraò, Angela; Barnaba, Carla; Peruzza, Laura

    2016-04-01

    On 6 May 1976 an Ms=6.5 earthquake struck the Friuli area (NE Italy), causing about 1,000 casualties, and widespread destruction. Such event is the largest so far recorded in Northern Italy. After 40 years, the memory of a devastating earthquake remains in the urbanization, and in the people that lived that dreadful experience. However, the memories tend to vanish with the quake survivors demise and the celebration of the anniversary become a good opportunity to refresh the earthquake history, and the awareness of living in a seismic prone area. As seismologists, we believe that the seismic risk reduction starts from the education of the next generation. For this reason, we decided to celebrate the 40 anniversary planning a special educational campaign, mainly devoted to the schools and the young people, but it will give us the opportunity to check and, if necessary to raise, the level of seismic awareness of the local communities. The activities started on May 2015, with labs and lessons held in some schools, and the creation of a blog (https://versoi40anni.wordpress.com) to collect news, photos, video and all the materials related to the campaign. From February to May 2016, one day per week, we will open our seismological lab to the school visits, so that students can meet the seismologists, and we will cooperate with local science museums to enlarge the training offers on the earthquake topics. By continuing the efforts of our previous educational projects, the students of a school located in Gemona del Friuli, one of the small town destroyed by the 1976 earthquake, will be deeply involved in experimental activities, like seismic noise measurements for microzonation studies, so to be an active part of the seismic mitigation process. This and some other activities developed for the celebration of the 40 anniversary of the Friuli earthquake will be illustrated in this presentation.

  10. A Bifactor Multidimensional Item Response Theory Model for Differential Item Functioning Analysis on Testlet-Based Items

    Science.gov (United States)

    Fukuhara, Hirotaka; Kamata, Akihito

    2011-01-01

    A differential item functioning (DIF) detection method for testlet-based data was proposed and evaluated in this study. The proposed DIF model is an extension of a bifactor multidimensional item response theory (MIRT) model for testlets. Unlike traditional item response theory (IRT) DIF models, the proposed model takes testlet effects into…

  11. INTERDEPENDENCE OF COST AND QUALITY OF ITEMS OF REAL ESTATE

    Directory of Open Access Journals (Sweden)

    Lukmanova Inessa Galeevna

    2012-10-01

    Calculation of reduction of the overall cost of the real estate item that has improved quality indicators in comparison with the overall cost of the real estate item of satisfactory quality, taken as a benchmark, is made. The nature of interrelation between the quality of building works and maintenance expenses is provided. The overall cost of the item increases alongside with the increase of its quality, therefore the pre-set quality indicator should be defined by taking account of the market conditions, rates charged for building works and payable by buyers, and the amount of building works that sell at a higher price. The indicator of the overall cost of the item of real estate, if forthcoming operational expenses are taken into account, i.e. calculated for the course of the overall life cycle of the item, is essential if the investor is going to maintain the building. Investors often act as sellers of completed buildings; therefore, the product price set at the time when it is offered for sale is of particular importance.

  12. Item calibration in incomplete testing designs

    NARCIS (Netherlands)

    Eggen, Theo J.H.M.; Verhelst, Norman D.

    2011-01-01

    This study discusses the justifiability of item parameter estimation in incomplete testing designs in item response theory. Marginal maximum likelihood (MML) as well as conditional maximum likelihood (CML) procedures are considered in three commonly used incomplete designs: random incomplete, multis

  13. An item response theory analysis of the narcissistic personality inventory.

    Science.gov (United States)

    Ackerman, Robert A; Donnellan, M Brent; Robins, Richard W

    2012-01-01

    This research uses item response theory methods to evaluate the Narcissistic Personality Inventory (NPI; Raskin & Terry, 1988). Analyses using the 2-parameter logistic model were conducted on the total score and the Corry, Merritt, Mrug, and Pamp (2008) and Ackerman et al. (2011) subscales for the NPI. In addition to offering precise information about the psychometric properties of the NPI item pool, these analyses generated insights that can be used to develop new measures of the personality constructs embedded within this frequently used inventory.

  14. Processing Polarity Items: Contrastive Licensing Costs

    Science.gov (United States)

    Saddy, Douglas; Drenhaus, Heiner; Frisch, Stefan

    2004-01-01

    We describe an experiment that investigated the failure to license polarity items in German using event-related brain potentials (ERPs). The results reveal distinct processing reflexes associated with failure to license positive polarity items in comparison to failure to license negative polarity items. Failure to license both negative and…

  15. Towards an authoring system for item construction

    NARCIS (Netherlands)

    Rikers, Jos H.A.N.

    1988-01-01

    The process of writing test items is analyzed, and a blueprint is presented for an authoring system for test item writing to reduce invalidity and to structure the process of item writing. The developmental methodology is introduced, and the first steps in the process are reported. A historical revi

  16. Generalized Full-Information Item Bifactor Analysis

    Science.gov (United States)

    Cai, Li; Yang, Ji Seung; Hansen, Mark

    2011-01-01

    Full-information item bifactor analysis is an important statistical method in psychological and educational measurement. Current methods are limited to single-group analysis and inflexible in the types of item response models supported. We propose a flexible multiple-group item bifactor analysis framework that supports a variety of…

  17. Real and Artificial Differential Item Functioning

    Science.gov (United States)

    Andrich, David; Hagquist, Curt

    2012-01-01

    The literature in modern test theory on procedures for identifying items with differential item functioning (DIF) among two groups of persons includes the Mantel-Haenszel (MH) procedure. Generally, it is not recognized explicitly that if there is real DIF in some items which favor one group, then as an artifact of this procedure, artificial DIF…

  18. Item Response Methods for Educational Assessment.

    Science.gov (United States)

    Mislevy, Robert J.; Rieser, Mark R.

    Multiple matrix sampling (MMS) theory indicates how data may be gathered to most efficiently convey information about levels of attainment in a population, but standard analyses of these data require random sampling of items from a fixed pool of items. This assumption proscribes the retirement of flawed or obsolete items from the pool as well as…

  19. Matrix Sampling of Test Items. ERIC Digest.

    Science.gov (United States)

    Childs, Ruth A.; Jaciw, Andrew P.

    This Digest describes matrix sampling of test items as an approach to achieving broad coverage while minimizing testing time per student. Matrix sampling involves developing a complete set of items judged to cover the curriculum, then dividing the items into subsets and administering one subset to each student. Matrix sampling, by limiting the…

  20. The Multidimensionality of Verbal Analogy Items

    Science.gov (United States)

    Ullstadius, Eva; Carlstedt, Berit; Gustafsson, Jan-Eric

    2008-01-01

    The influence of general and verbal ability on each of 72 verbal analogy test items were investigated with new factor analytical techniques. The analogy items together with the Computerized Swedish Enlistment Battery (CAT-SEB) were given randomly to two samples of 18-year-old male conscripts (n = 8566 and n = 5289). Thirty-two of the 72 items had…

  1. Intact Transition Epitope Mapping (ITEM)

    Science.gov (United States)

    Yefremova, Yelena; Opuni, Kwabena F. M.; Danquah, Bright D.; Thiesen, Hans-Juergen; Glocker, Michael O.

    2017-08-01

    Intact transition epitope mapping (ITEM) enables rapid and accurate determination of protein antigen-derived epitopes by either epitope extraction or epitope excision. Upon formation of the antigen peptide-containing immune complex in solution, the entire mixture is electrosprayed to translate all constituents as protonated ions into the gas phase. There, ions from antibody-peptide complexes are separated from unbound peptide ions according to their masses, charges, and shapes either by ion mobility drift or by quadrupole ion filtering. Subsequently, immune complexes are dissociated by collision induced fragmentation and the ion signals of the "complex-released peptides," which in effect are the epitope peptides, are recorded in the time-of-flight analyzer of the mass spectrometer. Mixing of an antibody solution with a solution in which antigens or antigen-derived peptides are dissolved is, together with antigen proteolysis, the only required in-solution handling step. Simplicity of sample handling and speed of analysis together with very low sample consumption makes ITEM faster and easier to perform than other experimental epitope mapping methods.

  2. Multi-item direct behavior ratings: Dependability of two levels of assessment specificity.

    Science.gov (United States)

    Volpe, Robert J; Briesch, Amy M

    2015-09-01

    Direct Behavior Rating-Multi-Item Scales (DBR-MIS) have been developed as formative measures of behavioral assessment for use in school-based problem-solving models. Initial research has examined the dependability of composite scores generated by summing all items comprising the scales. However, it has been argued that DBR-MIS may offer assessment of 2 levels of behavioral specificity (i.e., item-level, global composite-level). Further, it has been argued that scales can be individualized for each student to improve efficiency without sacrificing technical characteristics. The current study examines the dependability of 5 items comprising a DBR-MIS designed to measure classroom disruptive behavior. A series of generalizability theory and decision studies were conducted to examine the dependability of each item (calls out, noisy, clowns around, talks to classmates and out of seat), as well as a 3-item composite that was individualized for each student. Seven graduate students rated the behavior of 9 middle-school students on each item over 3 occasions. Ratings were based on 10-min video clips of students during mathematics instruction. Separate generalizability and decision studies were conducted for each item and for a 3-item composite that was individualized for each student based on the highest rated items on the first rating occasion. Findings indicate favorable dependability estimates for 3 of the 5 items and exceptional dependability estimates for the individualized composite.

  3. Expected linking error resulting from item parameter drift among the common Items on Rasch calibrated tests.

    Science.gov (United States)

    Miller, G Edward; Gesn, Paul Randall; Rotou, Jourania

    2005-01-01

    In state assessment programs that employ Rasch-based common item linking procedures, the linking constant is usually estimated with only those common items not identified as exhibiting item difficulty parameter drift. Since state assessments typically contain a fixed number of items, an item classified as exhibiting parameter drift during the linking process remains on the exam as a scorable item even if it is removed from the common item set. Under the assumption that item parameter drift has occurred for one or more of the common items, the expected effect of including or excluding the "affected" item(s) in the estimation of the linking constant is derived in this article. If the item parameter drift is due solely to factors not associated with a change in examinee achievement, no linking error will (be expected to) occur given that the linking constant is estimated only with the items not identified as "affected"; linking error will (be expected to) occur if the linking constant is estimated with all common items. However, if the item parameter drift is due solely to change in examinee achievement, the opposite is true: no linking error will (be expected to) occur if the linking constant is estimated with all common items; linking error will (be expected to) occur if the linking constant is estimated only with the items not identified as "affected".

  4. An Efficient Algorithm for Mining Maximal Frequent Item Sets

    Directory of Open Access Journals (Sweden)

    A. M.J.M.Z. Rahman

    2008-01-01

    Full Text Available Problem Statement: In today's life, the mining of frequent patterns is a basic problem in data mining applications. The algorithms which are used to generate these frequent patterns must perform efficiently. The objective was to propose an effective algorithm which generates frequent patterns in less time. Approach: We proposed an algorithm which was based on hashing technique and combines a vertical tidset representation of the database with effective pruning mechanisms. It removes all the non-maximal frequent item-sets to get exact set of MFI directly. It worked efficiently when the number of item-sets and tid-sets is more. Results: The performance of our algorithm had been compared with recently developed MAFIA algorithm and the results show how our algorithm gives better performance. Conclusions: Hence, the proposed algorithm performs effectively and generates frequent patterns faster.

  5. Modeling for the SAFRR Tsunami Scenario-generation, propagation, inundation, and currents in ports and harbors: Chapter D in The SAFRR (Science Application for Risk Reduction) Tsunami Scenario

    Science.gov (United States)

    ,

    2013-01-01

    This U.S. Geological Survey (USGS) Open-File report presents a compilation of tsunami modeling studies for the Science Application for Risk Reduction (SAFRR) tsunami scenario. These modeling studies are based on an earthquake source specified by the SAFRR tsunami source working group (Kirby and others, 2013). The modeling studies in this report are organized into three groups. The first group relates to tsunami generation. The effects that source discretization and horizontal displacement have on tsunami initial conditions are examined in section 1 (Whitmore and others). In section 2 (Ryan and others), dynamic earthquake rupture models are explored in modeling tsunami generation. These models calculate slip distribution and vertical displacement of the seafloor as a result of realistic fault friction, physical properties of rocks surrounding the fault, and dynamic stresses resolved on the fault. The second group of papers relates to tsunami propagation and inundation modeling. Section 3 (Thio) presents a modeling study for the entire California coast that includes runup and inundation modeling where there is significant exposure and estimates of maximum velocity and momentum flux at the shoreline. In section 4 (Borrero and others), modeling of tsunami propagation and high-resolution inundation of critical locations in southern California is performed using the National Oceanic and Atmospheric Administration’s (NOAA) Method of Splitting Tsunami (MOST) model and NOAA’s Community Model Interface for Tsunamis (ComMIT) modeling tool. Adjustments to the inundation line owing to fine-scale structures such as levees are described in section 5 (Wilson). The third group of papers relates to modeling of hydrodynamics in ports and harbors. Section 6 (Nicolsky and Suleimani) presents results of the model used at the Alaska Earthquake Information Center for the Ports of Los Angeles and Long Beach, as well as synthetic time series of the modeled tsunami for other selected

  6. Impact of Local Item Dependence on True-Score Equating. LSAC Research Report Series.

    Science.gov (United States)

    Reese, Lynda M.; Pashley, Peter J.

    This study investigated the practical effects of local item dependence (LID) on item response theory (IRT) true-score equating. A scenario was defined that emulated the Law School Admission Test (LSAT) preequating model, and data were generated to assess the impact of different degrees of LID on final equating outcomes. An extreme amount of LID…

  7. Purchasing Nonprescription Contraceptives: The Underlying Structure of a Multi-Item Scale.

    Science.gov (United States)

    Manolis, Chris; Winsor, Robert D.; True, Sheb L.

    1999-01-01

    Developed a multi-item scale for measuring attitudes associated with purchasing nonprescription contraceptives using construct specification and item generation and confirmatory factor analysis. Demonstrated a high degree of invariance across samples of 81 female and 115 male adult consumers. (SLD)

  8. Logistics Reduction and Repurposing Technology for Long Duration Space Missions

    Science.gov (United States)

    Broyan, James L.; Chu, Andrew; Ewert, Michael K.

    2014-01-01

    One of NASA's Advanced Exploration Systems (AES) projects is the Logistics Reduction and Repurposing (LRR) project, which has the goal of reducing logistics resupply items through direct and indirect means. Various technologies under development in the project will reduce the launch mass of consumables and their packaging, enable reuse and repurposing of items and make logistics tracking more efficient. Repurposing also reduces the trash burden onboard spacecraft and indirectly reduces launch mass by replacing some items on the manifest. Examples include reuse of trash as radiation shielding or propellant. This paper provides the status of the LRR technologies in their third year of development under AES. Advanced clothing systems (ACS) are being developed to enable clothing to be worn longer, directly reducing launch mass. ACS has completed a ground exercise clothing study in preparation for an International Space Station (ISS) technology demonstration in 2014. Development of launch packaging containers and other items that can be repurposed on-orbit as part of habitation outfitting has resulted in a logistics-to-living (L2L) concept. L2L has fabricated and evaluated several multi-purpose cargo transfer bags (MCTBs) for potential reuse on orbit. Autonomous logistics management (ALM) is using radio frequency identification (RFID) to track items and thus reduce crew requirements for logistics functions. An RFID dense reader prototype is under construction and plans for integrated testing are being made. Development of a heat melt compactor (HMC) second generation unit for processing trash into compact and stable tiles is nearing completion. The HMC prototype compaction chamber has been completed and system development testing is underway. Research has been conducted on the conversion of trash-to-gas (TtG) for high levels of volume reduction and for use in propulsion systems. A steam reformation system was selected for further system definition of the TtG technology

  9. Losing Items in the Psychogeriatric Nursing Home

    Directory of Open Access Journals (Sweden)

    J. van Hoof PhD

    2016-09-01

    Full Text Available Introduction: Losing items is a time-consuming occurrence in nursing homes that is ill described. An explorative study was conducted to investigate which items got lost by nursing home residents, and how this affects the residents and family caregivers. Method: Semi-structured interviews and card sorting tasks were conducted with 12 residents with early-stage dementia and 12 family caregivers. Thematic analysis was applied to the outcomes of the sessions. Results: The participants stated that numerous personal items and assistive devices get lost in the nursing home environment, which had various emotional, practical, and financial implications. Significant amounts of time are spent on trying to find items, varying from 1 hr up to a couple of weeks. Numerous potential solutions were identified by the interviewees. Discussion: Losing items often goes together with limitations to the participation of residents. Many family caregivers are reluctant to replace lost items, as these items may get lost again.

  10. New technologies for item monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, J.A. [EG & G Energy Measurements, Albuquerque, NM (United States); Waddoups, I.G. [Sandia National Labs., Albuquerque, NM (United States)

    1993-12-01

    This report responds to the Department of Energy`s request that Sandia National Laboratories compare existing technologies against several advanced technologies as they apply to DOE needs to monitor the movement of material, weapons, or personnel for safety and security programs. The authors describe several material control systems, discuss their technologies, suggest possible applications, discuss assets and limitations, and project costs for each system. The following systems are described: WATCH system (Wireless Alarm Transmission of Container Handling); Tag system (an electrostatic proximity sensor); PANTRAK system (Personnel And Material Tracking); VRIS (Vault Remote Inventory System); VSIS (Vault Safety and Inventory System); AIMS (Authenticated Item Monitoring System); EIVS (Experimental Inventory Verification System); Metrox system (canister monitoring system); TCATS (Target Cueing And Tracking System); LGVSS (Light Grid Vault Surveillance System); CSS (Container Safeguards System); SAMMS (Security Alarm and Material Monitoring System); FOIDS (Fiber Optic Intelligence & Detection System); GRADS (Graded Radiation Detection System); and PINPAL (Physical Inventory Pallet).

  11. Reversed item bias: an integrative model.

    Science.gov (United States)

    Weijters, Bert; Baumgartner, Hans; Schillewaert, Niels

    2013-09-01

    In the recent methodological literature, various models have been proposed to account for the phenomenon that reversed items (defined as items for which respondents' scores have to be recoded in order to make the direction of keying consistent across all items) tend to lead to problematic responses. In this article we propose an integrative conceptualization of three important sources of reversed item method bias (acquiescence, careless responding, and confirmation bias) and specify a multisample confirmatory factor analysis model with 2 method factors to empirically test the hypothesized mechanisms, using explicit measures of acquiescence and carelessness and experimentally manipulated versions of a questionnaire that varies 3 item arrangements and the keying direction of the first item measuring the focal construct. We explain the mechanisms, review prior attempts to model reversed item bias, present our new model, and apply it to responses to a 4-item self-esteem scale (N = 306) and the 6-item Revised Life Orientation Test (N = 595). Based on the literature review and the empirical results, we formulate recommendations on how to use reversed items in questionnaires.

  12. Development of an item list to assess the forgotten joint concept in shoulder patients.

    Science.gov (United States)

    Giesinger, Johannes M; Kesterke, Nicolas; Hamilton, David F; Holzner, Bernhard; Jost, Bernhard; Giesinger, Karlmeinrad

    2015-03-24

    To generate an item list for the assessment of joint awareness in shoulder patients and to collect patient feedback on the comprehensibility of the items and the forgotten joint concept. Item content was generated on the basis of literature search and expert ratings following a stepwise refinement procedure, including final evaluation by an international expert board (n = 12) including members with various professional backgrounds. Items were translated from English to German and evaluated in 30 German-speaking shoulder patients in Switzerland and 30 shoulder patients in the UK. Literature search identified 45 questionnaires covering 805 issues potentially relevant for the assessment of joint awareness. Stepwise item selection resulted in 97 items to be evaluated by the international expert board leaving 70 items for collecting patient feedback. The majority of patients indicated that the introductory text explaining the forgotten joint concept was easy or very easy to understand (79.3%) and that the items were clear (91.4%). We developed a list of 70 questions for the assessment of joint awareness in shoulder patients and obtained positive patient feedback for these. In a next step, we will administer the items to a large international patient sample to obtain data for psychometric analysis and development of a measurement model, which is the basis for creation of computer-adaptive assessments or static short-forms.

  13. Defining a Standard for Reporting Digital Evidence Items in Computer Forensic Tools

    Science.gov (United States)

    Bariki, Hamda; Hashmi, Mariam; Baggili, Ibrahim

    Due to the lack of standards in reporting digital evidence items, investigators are facing difficulties in efficiently presenting their findings. This paper proposes a standard for digital evidence to be used in reports that are generated using computer forensic software tools. The authors focused on developing a standard digital evidence items by surveying various digital forensic tools while keeping in mind the legal integrity of digital evidence items. Additionally, an online questionnaire was used to gain the opinion of knowledgeable and experienced stakeholders in the digital forensics domain. Based on the findings, the authors propose a standard for digital evidence items that includes data about the case, the evidence source, evidence item, and the chain of custody. Research results enabled the authors in creating a defined XML schema for digital evidence items.

  14. Examining item difficulty and response time on perceptual ability test items.

    Science.gov (United States)

    Yang, Chien-Lin; O'Neill, Thomas R; Kramer, Gene A

    2002-01-01

    This study examined item calibration stability in relation to response time and the levels of item difficulty between different response time groups on a sample of 389 examinees responding to six different subtest items of the Perceptual Ability Test (PAT). The results indicated that no Differential Item Functioning (DIF) was found and a significant correlation coefficient of item difficulty was formed between slow and fast responders. Three distinct levels of difficulty emerged among the six subtests across groups. Slow responders spent significantly more time than fast responders on the four most difficult subtests. A positive significant relationship was found between item difficulty and response time across groups on the overall perceptual ability test items. Overall, this study found that: 1) the same underlying construct is being measured across groups, 2) the PAT scores were equally useful across groups, 3) different sources of item difficulty may exist among the six subtests, and 4) more difficult test items may require more time to answer.

  15. From concepts to lexical items.

    Science.gov (United States)

    Bierwisch, M; Schreuder, R

    1992-03-01

    In this paper we address the question how in language production conceptual structures are mapped onto lexical items. First we describe the lexical system in a fairly abstract way. Such a system consists of, among other things, a fixed set of basic lexical entries characterized by four groups of information: phonetic form, grammatical features, argument structure, and semantic form. A crucial assumption of the paper is that the meaning in a lexical entry has a complex internal structure composed of more primitive elements (decomposition). Some aspects of argument structure and semantic form and their interaction are discussed with respect to the issue of synonymy. We propose two different mappings involved in lexical access. One maps conceptual structures to semantic forms, and the other maps semantic forms to conceptual structures. Both mappings are context dependent and are many-to-many mappings. We present an elaboration of Levelt's (1989) model in which these processes interact with the grammatical encoder and the mental lexicon. Then we address the consequences of decomposition for processing models, especially the nature of the input of lexical access and the time course. Processing models that use the activation metaphor may have difficulties accounting for certain phenomena where a certain lemma triggers not one, but two or more word forms that have to be produced with other word forms in between.

  16. Generation IV Nuclear Energy Systems Construction Cost Reductions through the Use of Virtual Environments - Task 4 Report: Virtual Mockup Maintenance Task Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Timothy Shaw; Anthony Baratta; Vaughn Whisker

    2005-02-28

    Task 4 report of 3 year DOE NERI-sponsored effort evaluating immersive virtual reality (CAVE) technology for design review, construction planning, and maintenance planning and training for next generation nuclear power plants. Program covers development of full-scale virtual mockups generated from 3D CAD data presented in a CAVE visualization facility. This report focuses on using Full-scale virtual mockups for nuclear power plant training applications.

  17. Reducing the item number to obtain the same-length self-assessment scales: a systematic approach using result of graphical loglinear rasch models

    DEFF Research Database (Denmark)

    Nielsen, Tine; Kreiner, Svend

    2011-01-01

    approach to item reduction based on results of graphical loglinear Rasch modeling (GLLRM) was designed. This approach was then used to reduce the number of items in the subscales of the R-D-LSI which had an item-length of more than seven items, thereby obtaining the Danish Self-Assessment Learning Styles......The Revised Danish Learning Styles Inventory (R-D-LSI) (Nielsen 2005), which is an adaptation of Sternberg- Wagner Thinking Styles Inventory (Sternberg, 1997), comprises 14 subscales, each measuring a separate learning style. Of these 14 subscales, 9 are eight items long and 5 are seven items long...

  18. An Integrated Vendor-Buyer Cooperative Inventory Model for Items with Imperfect Quality and Shortage Backordering

    Directory of Open Access Journals (Sweden)

    Jia-Tzer Hsu

    2012-01-01

    Full Text Available We develop a model to determine an integrated vendor-buyer inventory policy for items with imperfect quality and planned backorders. The production process is imperfect and produces a certain number of defective items with a known probability density function. The vendor delivers the items to the buyer in small lots of equally sized shipments. Upon receipt of the items, the buyer will conduct a 100% inspection. Since each lot contains a variable number of defective items, shortages may occur at the buyer. We assume that shortages are permitted and are completely backordered. The objective is to minimize the total joint annual costs incurred by the vendor and the buyer. The expected total annual integrated cost is derived and a solution procedure is provided to find the optimal solution. Numerical examples show that the integrated model gives an impressive cost reduction in comparison to an independent decision by the buyer.

  19. Energy-saving and Emission Reduction Planning on Power Generation Side Based on Fuzzy Feasibility Analysis%基于模糊可行性分析的发电侧节能减排规划

    Institute of Scientific and Technical Information of China (English)

    胡情; 黄国和; 李薇; 蔡宴朋

    2013-01-01

    应对节能减排要求,针对发电侧能源活动之间及其与环境之间的复杂性和经济、技术、环境及能源资源可获得量等参数的不确定性,结合传统的不确定性规划和基于可行性分析的模糊规划,建立了发电侧节能减排不确定性优化模型.该模型以发电侧运行成本最小化为目标,集能源供应、转化和消费,转化技术的选择和技术的改扩建,电力生产和污染消减为一体,综合考虑了系统参数的区间和模糊不确定性,使规划结果更具有实际可操作性.同时将该模型应用于一个典型的电力系统发电侧规划中,产生了可行性的能源供应、电力生产、技术扩容、污染排放消减方案.%To meet the requirements of energy-saving and e-mission reduction, a feasibility based inexact optimization model was developed by introducing feasibility based fuzzy program into a traditional interval program frame. It could deal with the complexities between energy activities and environmental systems, and uncertainties in economic, technical, environmental parameters and parameters about energy resources availabilities during energy-saving and emission reduction planning of power generation side. The objective of the model was to minimize the operation system costs, which consisted of costs from energy supply, conversion and consumption, renovations and expansions of conversion technologies, electricity generation and pollutants reduction. Moreover, the model could combine the uncertainties in system parameters expressed as intervals and fuzzy numbers into the optimization process, which would make the planning results more practical. Then the model was applied to a typical e-lectric power system to support energy saving and emission reduction planning of generation side. Desired energy supply, electricity generation, capacity expansion and emission reduction plans with minimized system costs had been generated.

  20. Detection of Differential Item Functioning Using the Lasso Approach

    Science.gov (United States)

    Magis, David; Tuerlinckx, Francis; De Boeck, Paul

    2015-01-01

    This article proposes a novel approach to detect differential item functioning (DIF) among dichotomously scored items. Unlike standard DIF methods that perform an item-by-item analysis, we propose the "LR lasso DIF method": logistic regression (LR) model is formulated for all item responses. The model contains item-specific intercepts,…

  1. An Item Analysis and Validity Investigation of Bender Visual Motor Gestalt Test Score Items

    Science.gov (United States)

    Lambert, Nadine M.

    1971-01-01

    This investigation attempted to demonstrate the utility of standard item analysis procedures for selecting the most reliable and valid items for scoring Bender Visual Motor Gestalt Test test records. (Author)

  2. Frontier of CO{sub 2} reduction/sink with international Win/Win Corporation - coal fired electric power generation helps afforestation through by product utilization

    Energy Technology Data Exchange (ETDEWEB)

    Yoshitaka, N.; Kaori, A.; Kazuo, W.; Katsumi, O. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    2001-07-01

    Several countries in Asia require coal fired electric power generation because they are rich in domestic coal. In common sense, coal firing generates carbon dioxide and sulfur dioxide more than natural gas, thus it tends to be disliked for electric power generation. When desulfurization plants are housed, these cost much and produce valuable by-poducts. Gypsum is a by-product from desulfurization plant, which can reclaim very poor alkaline or sodic soil and the combination of gypsum and quick lime is a by-product from fluidized-bed boiler and bio-briquet, which can reclaim very poor acidic soil. These two principal by-products are the key to afforestation, resulting in carbon sink. Sometimes soil reclamation can change poor soil into fertile soil which is useful for agriculture. 2 tabs.

  3. 76 FR 60474 - Commercial Item Handbook

    Science.gov (United States)

    2011-09-29

    ... Defense Acquisition Regulations System Commercial Item Handbook AGENCY: Defense Acquisition Regulations... Commercial Item Handbook. The purpose of the Handbook is to help acquisition personnel develop sound business... the Handbook. DATES: Comments should be submitted in writing to the address shown below on or before...

  4. Item nonresponse in questionnaire research with children

    NARCIS (Netherlands)

    Hox, J.J.; Borgers, N.

    2001-01-01

    This study investigates the effect of item and person characteristics on item nonresponse, for written questionnaires used with school children. Secondary analyses were done on questionnaire data collected in five distinct studies. To analyze the data, logistic multilevel analysis was used with the

  5. Restricted Interests and Teacher Presentation of Items

    Science.gov (United States)

    Stocco, Corey S.; Thompson, Rachel H.; Rodriguez, Nicole M.

    2011-01-01

    Restricted and repetitive behavior (RRB) is more pervasive, prevalent, frequent, and severe in individuals with autism spectrum disorders (ASDs) than in their typical peers. One subtype of RRB is restricted interests in items or activities, which is evident in the manner in which individuals engage with items (e.g., repetitious wheel spinning),…

  6. Item Calibration in Incomplete Testing Designs

    Science.gov (United States)

    Eggen, Theo J. H. M.; Verhelst, Norman D.

    2011-01-01

    This study discusses the justifiability of item parameter estimation in incomplete testing designs in item response theory. Marginal maximum likelihood (MML) as well as conditional maximum likelihood (CML) procedures are considered in three commonly used incomplete designs: random incomplete, multistage testing and targeted testing designs.…

  7. Grouping of Items in Mobile Web Questionnaires

    Science.gov (United States)

    Mavletova, Aigul; Couper, Mick P.

    2016-01-01

    There is some evidence that a scrolling design may reduce breakoffs in mobile web surveys compared to a paging design, but there is little empirical evidence to guide the choice of the optimal number of items per page. We investigate the effect of the number of items presented on a page on data quality in two types of questionnaires: with or…

  8. 38 CFR 3.1606 - Transportation items.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Transportation items. 3... Burial Benefits § 3.1606 Transportation items. The transportation costs of those persons who come within... shipment. (6) Cost of transportation by common carrier including amounts paid as Federal taxes. (7) Cost...

  9. Interservice Availability of Multiservice Used Items.

    Science.gov (United States)

    1999-05-14

    t PIVT OF DISTRIBUTION STATEMENT A Approved for Public Releaseo r. Distribution Unlimited 19990817 034 INTERSERVICE AVAILABILTY OF MULTISERVICE USED...was initially cataloged or placed in the DoD supply system. As items matured, that is, as recurring item costs, usage rates, and technological

  10. Development of the Oxford Participation and Activities Questionnaire: constructing an item pool

    Directory of Open Access Journals (Sweden)

    Kelly L

    2015-05-01

    Full Text Available Laura Kelly, Crispin Jenkinson, Sarah Dummett, Jill Dawson, Ray Fitzpatrick, David Morley Health Services Research Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK Purpose: The Oxford Participation and Activities Questionnaire is a patient-reported outcome measure in development that is grounded on the World Health Organization International Classification of Functioning, Disability, and Health (ICF. The study reported here aimed to inform and generate an item pool for the new measure, which is specifically designed for the assessment of participation and activity in patients experiencing a range of health conditions. Methods: Items were informed through in-depth interviews conducted with 37 participants spanning a range of conditions. Interviews aimed to identify how their condition impacted their ability to participate in meaningful activities. Conditions included arthritis, cancer, chronic back pain, diabetes, motor neuron disease, multiple sclerosis, Parkinson's disease, and spinal cord injury. Transcripts were analyzed using the framework method. Statements relating to ICF themes were recast as questionnaire items and shown for review to an expert panel. Cognitive debrief interviews (n=13 were used to assess items for face and content validity. Results: ICF themes relevant to activities and participation in everyday life were explored, and a total of 222 items formed the initial item pool. This item pool was refined by the research team and 28 generic items were mapped onto all nine chapters of the ICF construct, detailing activity and participation. Cognitive interviewing confirmed the questionnaire instructions, items, and response options were acceptable to participants. Conclusion: Using a clear conceptual basis to inform item generation, 28 items have been identified as suitable to undergo further psychometric testing. A large-scale postal survey will follow in order to refine the instrument further and

  11. Choosing wisely: the Canadian Rheumatology Association's list of 5 items physicians and patients should question.

    Science.gov (United States)

    Chow, Shirley L; Carter Thorne, J; Bell, Mary J; Ferrari, Robert; Bagheri, Zarnaz; Boyd, Tristan; Colwill, Ann Marie; Jung, Michelle; Frackowiak, Damian; Hazlewood, Glen S; Kuriya, Bindee; Tugwell, Peter

    2015-04-01

    To develop a list of 5 tests or treatments used in rheumatology that have evidence indicating that they may be unnecessary and thus should be reevaluated by rheumatology healthcare providers and patients. Using the Delphi method, a committee of 16 rheumatologists from across Canada and an allied health professional generated a list of tests, procedures, or treatments in rheumatology that may be unnecessary, nonspecific, or insensitive. Items with high content agreement and perceived relevance advanced to a survey of Canadian Rheumatology Association (CRA) members. CRA members ranked these top items based on content agreement, effect, and item ranking. A methodology subcommittee discussed the items in light of their relevance to rheumatology, potential effect on patients, and the member survey results. Five candidate items selected were then subjected to a literature review. A group of patient collaborators with rheumatic diseases also reviewed these items. Sixty-four unique items were proposed and after 3 Delphi rounds, this list was narrowed down to 13 items. In the member-wide survey, 172 rheumatologists responded (36% of those contacted). The respondent characteristics were similar to the membership at large in terms of sex and geographical distribution. Five topics (antinuclear antibodies testing, HLA-B27 testing, bone density testing, bone scans, and bisphosphonate use) with high ratings on agreement and effect were chosen for literature review. The list of 5 items has identified starting points to promote discussion about practices that should be questioned to assist rheumatology healthcare providers in delivering high-quality care.

  12. Attending multiple items decreases the selectivity of population responses in human primary visual cortex.

    Science.gov (United States)

    Anderson, David E; Ester, Edward F; Serences, John T; Awh, Edward

    2013-05-29

    Multiple studies have documented an inverse relationship between the number of to-be-attended or remembered items in a display ("set size") and task performance. The neural source of this decline in cognitive performance is currently under debate. Here, we used a combination of fMRI and a forward encoding model of orientation selectivity to generate population tuning functions for each of two stimuli while human observers attended either one or both items. We observed (1) clear population tuning functions for the attended item(s) that peaked at the stimulus orientation and decreased monotonically as the angular distance from this orientation increased, (2) a set-size-dependent decline in the relative precision of orientation-specific population responses, such that attending two items yielded a decline in selectivity of the population tuning function for each item, and (3) that the magnitude of the loss of precision in population tuning functions predicted individual differences in the behavioral cost of attending an additional item. These findings demonstrate that attending multiple items degrades the precision of perceptual representations for the target items and provides a straightforward account for the associated impairments in visually guided behavior.

  13. The use of an item response theory-based disability item bank across diseases: accounting for differential item functioning.

    Science.gov (United States)

    Weisscher, Nadine; Glas, Cees A; Vermeulen, Marinus; De Haan, Rob J

    2010-05-01

    There is not a single universally accepted activity of daily living (ADL) instrument available to compare disability assessments across different patient groups. We developed a generic item bank of ADL items using item response theory, the Academic Medical Center Linear Disability Scale (ALDS). When comparing outcomes of the ALDS between patients groups, item characteristics of the ALDS should be comparable across groups. The aim of the study was to assess the differential item functioning (DIF) in a group of patients with various disorders to investigate the comparability across these groups. Cross-sectional, multicenter study including 1,283 in- and outpatients with a variety of disorders and disability levels. The sample was divided in two groups: (1) mainly neurological patients (n=497; vascular medicine, Parkinson's disease and neuromuscular disorders) and (2) patients from internal medicine (n=786; pulmonary diseases, chronic pain, rheumatoid arthritis, and geriatric patients). Eighteen of 72 ALDS items showed statistically significant DIF (P<0.01). However, the DIF could effectively be modeled by the introduction of disease-specific parameters. In the subgroups studied, DIF could be modeled in such a way that the ensemble of the items comprised a scale applicable in both groups.

  14. Item response theory - A first approach

    Science.gov (United States)

    Nunes, Sandra; Oliveira, Teresa; Oliveira, Amílcar

    2017-07-01

    The Item Response Theory (IRT) has become one of the most popular scoring frameworks for measurement data, frequently used in computerized adaptive testing, cognitively diagnostic assessment and test equating. According to Andrade et al. (2000), IRT can be defined as a set of mathematical models (Item Response Models - IRM) constructed to represent the probability of an individual giving the right answer to an item of a particular test. The number of Item Responsible Models available to measurement analysis has increased considerably in the last fifteen years due to increasing computer power and due to a demand for accuracy and more meaningful inferences grounded in complex data. The developments in modeling with Item Response Theory were related with developments in estimation theory, most remarkably Bayesian estimation with Markov chain Monte Carlo algorithms (Patz & Junker, 1999). The popularity of Item Response Theory has also implied numerous overviews in books and journals, and many connections between IRT and other statistical estimation procedures, such as factor analysis and structural equation modeling, have been made repeatedly (Van der Lindem & Hambleton, 1997). As stated before the Item Response Theory covers a variety of measurement models, ranging from basic one-dimensional models for dichotomously and polytomously scored items and their multidimensional analogues to models that incorporate information about cognitive sub-processes which influence the overall item response process. The aim of this work is to introduce the main concepts associated with one-dimensional models of Item Response Theory, to specify the logistic models with one, two and three parameters, to discuss some properties of these models and to present the main estimation procedures.

  15. AN ITEM RESPONSE MODEL WITH SINGLE PEAKED ITEM CHARACTERISTIC CURVES - THE PARELLA MODEL

    NARCIS (Netherlands)

    HOIJTINK, H; MOLENAAR, [No Value

    In this paper an item response model (the PARELLA model) designed specifically for the measurement of attitudes and preferences will be introduced. In contrast with the item response models currently used (e.g. the Rasch model and, the two and three parameter logistic model) the item characteristic

  16. Comparing Methods for Item Analysis: The Impact of Different Item-Selection Statistics on Test Difficulty

    Science.gov (United States)

    Jones, Andrew T.

    2011-01-01

    Practitioners often depend on item analysis to select items for exam forms and have a variety of options available to them. These include the point-biserial correlation, the agreement statistic, the B index, and the phi coefficient. Although research has demonstrated that these statistics can be useful for item selection, no research as of yet has…

  17. Developing and evaluating innovative items for the NCLEX: Part 2, item characteristics and cognitive processing.

    Science.gov (United States)

    Wendt, Anne; Harmes, J Christine

    2009-01-01

    This article is a continuation of the research on the development and evaluation of innovative item formats for the NCLEX examinations that was published in the March/April 2009 edition of Nurse Educator. The authors discuss the innovative item templates and evaluate the statistical characteristics and level of cognitive processing required to answer the examination items.

  18. Ramsay-Curve Item Response Theory for the Three-Parameter Logistic Item Response Model

    Science.gov (United States)

    Woods, Carol M.

    2008-01-01

    In Ramsay-curve item response theory (RC-IRT), the latent variable distribution is estimated simultaneously with the item parameters of a unidimensional item response model using marginal maximum likelihood estimation. This study evaluates RC-IRT for the three-parameter logistic (3PL) model with comparisons to the normal model and to the empirical…

  19. Evaluation of Northwest University, Kano Post-UTME Test Items Using Item Response Theory

    Science.gov (United States)

    Bichi, Ado Abdu; Hafiz, Hadiza; Bello, Samira Abdullahi

    2016-01-01

    High-stakes testing is used for the purposes of providing results that have important consequences. Validity is the cornerstone upon which all measurement systems are built. This study applied the Item Response Theory principles to analyse Northwest University Kano Post-UTME Economics test items. The developed fifty (50) economics test items was…

  20. Direct determination of arsenic in soil samples by fast pyrolysis–chemical vapor generation using sodium formate as a reductant followed by nondispersive atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Xuchuan; Zhang, Jingya; Bu, Fanlong

    2015-09-01

    This new study shows for the first time that sodium formate can react with trace arsenic to form volatile species via fast pyrolysis – chemical vapor generation. We found that the presence of thiourea greatly enhanced the generation efficiency and eliminated the interference of copper. We studied the reaction temperature, the volume of sodium formate, the reaction acidity, and the carried argon rate using nondispersive atomic fluorescence spectrometry. Under optimal conditions of T = 500 °C, the volumes of 30% sodium formate and 10% thiourea were 0.2 ml and 0.05 ml, respectively. The carrier argon rate was 300 ml min{sup −1} and the detection limit and precision of arsenic were 0.39 ng and 3.25%, respectively. The amount of arsenic in soil can be directly determined by adding trace amount of hydrochloric acid as a decomposition reagent without any sample pretreatment. The method was successfully applied to determine trace amount of arsenic in two soil-certified reference materials (GBW07453 and GBW07450), and the results were found to be in agreement with certified reference values. - Highlights: • Sodium formate can react with trace arsenic to form volatile species via pyrolysis–chemical vapor generation. • Thiourea can enhance the generation efficiency and eliminate the interference of copper. • Arsenic in soil Sample can be directly determined without sample pretreatment.

  1. Burners. The decrease of nitrogen oxides in combustion process: the 2 nd generation GR LONOxFLAM burner; Les bruleurs, la reduction des oxydes d`azote dans la combustion: bruleur GR LONOxFLAM de 2. generation

    Energy Technology Data Exchange (ETDEWEB)

    Gauthier, J.C. [EGCI Pillard, 13 - Marseille (France)

    1997-12-31

    The Pillard company has developed, in cooperation with GDF (the French national gas utility), the GR-LONOxFLAM burner concept for reducing NOx emission levels and solid combustion products. The concept consists, for gaseous fuels, in the combination of an internal recirculation and a gas staging process; for liquid fuels, a separated flame process and air staging are combined. These concepts allow for an important reduction in NOx and non-burned residues, even with standard-size burners

  2. Structure, Optical Properties, and Photocatalytic Activity towards H2 Generation and CO2 Reduction of GaN Nanowires via Vapor-Liquid-Solid Process

    Directory of Open Access Journals (Sweden)

    Hong Pang

    2014-01-01

    Full Text Available High quality single crystalline GaN nanowires with large aspect ratio (>100 are synthesized on n-type Si (111 substrate via Au-catalyzed vapor-liquid-solid process. Morphology, crystal structure, and optical property of the as-synthesized GaN nanowires are characterized by means of X-ray diffraction, scanning/transmission electron microscopy, UV-vis diffuse reflection spectroscopy, and room temperature photoluminescence. The results indicate that the as-prepared GaN nanowires with a large aspect ratio are well crystallized in the hexagonal wurtzite structure, and a slight blue shift appears in both the absorption edge and emission peak probably due to the quantization effect. Photocatalytic H2 evolution over the as-prepared GaN nanowires is performed with the incorporation of Pt or Rh as the cocatalyst, exhibiting greatly enhanced capability compared to the GaN powder tested under the same conditions. Moreover, photocatalytic CO2 reduction over the GaN nanowires is also successfully realized using Pt or Rh as the cocatalyst, depending on which the products show a strong selectivity inherently related to the reductive electrons transferred by cocatalyst.

  3. Measuring student learning with item response theory

    Directory of Open Access Journals (Sweden)

    Young-Jin Lee

    2008-01-01

    Full Text Available We investigate short-term learning from hints and feedback in a Web-based physics tutoring system. Both the skill of students and the difficulty and discrimination of items were determined by applying item response theory (IRT to the first answers of students who are working on for-credit homework items in an introductory Newtonian physics course. We show that after tutoring a shifted logistic item response function with lower discrimination fits the students’ second responses to an item previously answered incorrectly. Student skill decreased by 1.0 standard deviation when students used no tutoring between their (incorrect first and second attempts, which we attribute to “item-wrong bias.” On average, using hints or feedback increased students’ skill by 0.8 standard deviation. A skill increase of 1.9 standard deviation was observed when hints were requested after viewing, but prior to attempting to answer, a particular item. The skill changes measured in this way will enable the use of IRT to assess students based on their second attempt in a tutoring environment.

  4. Bookmark locations and item response model selection in the presence of local item dependence.

    Science.gov (United States)

    Skaggs, Gary

    2007-01-01

    The bookmark standard setting procedure is a popular method for setting performance standards on state assessment programs. This study reanalyzed data from an application of the bookmark procedure to a passage-based test that used the Rasch model to create the item ordered booklet. Several problems were noted in this implementation of the bookmark procedure, including disagreement among the SMEs about the correct order of items in the bookmark booklet, performance level descriptions of the passing standard being based on passage difficulty as well as item difficulty, and the presence of local item dependence within reading passages. Bookmark item locations were recalculated for the IRT three-parameter model and the multidimensional bifactor model. The results showed that the order of item locations was very similar for all three models when items of high difficulty and low discrimination were excluded. However, the items whose positions were the most discrepant between models were not the items that the SMEs disagreed about the most in the original standard setting. The choice of latent trait model did not address problems of item order disagreement. Implications for the use of the bookmark method in the presence of local item dependence are discussed.

  5. Sequential item pricing for unlimited supply

    OpenAIRE

    2010-01-01

    We investigate the extent to which price updates can increase the revenue of a seller with little prior information on demand. We study prior-free revenue maximization for a seller with unlimited supply of n item types facing m myopic buyers present for k < log n days. For the static (k = 1) case, Balcan et al. [2] show that one random item price (the same on each item) yields revenue within a \\Theta(log m + log n) factor of optimum and this factor is tight. We define the hereditary maximizer...

  6. Chelate bis(imino)pyridine cobalt complexes: synthesis, reduction, and evidence for the generation of ethene polymerization catalysts by Li+ cation activation.

    Science.gov (United States)

    Kleigrewe, Nina; Steffen, Winfried; Blömker, Tobias; Kehr, Gerald; Fröhlich, Roland; Wibbeling, Birgit; Erker, Gerhard; Wasilke, Julia-Christina; Wu, Guang; Bazan, Guillermo C

    2005-10-12

    Treatment of the bis(iminobenzyl)pyridine chelate Schiff-base ligand 8 (ligPh) with FeCl2 or CoCl2 yielded the corresponding (ligPh)MCl2 complexes 9 (Fe) and 10 (Co). The reaction of 10 with methyllithium or "butadiene-magnesium" resulted in reduction to give the corresponding (ligPh)Co(I)Cl product 11. Similarly, the bis(aryliminoethyl)pyridine ligand (ligMe) was reacted with CoCl2 to yield (ligMe)CoCl2 (12). Reduction to (ligMe)CoCl (13) was effected by treatment with "butadiene-magnesium". Complex 13 reacted with Li[B(C6F5)4] in toluene followed by treatment with pyridine to yield [(ligMe)Co+-pyridine] (15). The reaction of the Co(II) complexes 10 or 12 with ca. 3 molar equiv of methyllithium gave the cobalt(I) complexes 16 and 17, respectively. Treatment of the (ligMe)CoCH3 (17) with Li[B(C6F5)4] gave a low activity ethene polymerization catalyst. Likewise, complex 16 produced polyethylene (activity = 33 g(PE) mmol(cat)(-1) h(-1) bar(-1) at room temperature) upon treatment with a stoichiometric amount of Li[B(C6F5)4]. A third ligand (lig(OMe)) was synthesized featuring methoxy groups in the ligand backbone (22). Coordination to FeCl2 and CoCl2 yielded the desired compounds 23 and 24. Reaction with MeLi gave (ligOMe)CoMe (25/26). Treatment of 25/26 with excess B(C6F5)3 gave the eta6-arene cation complex 27, where one Co-N linkage was cleaved. Activation of 25/26 with Li[B(C6F5)4] again gave a catalytically active species.

  7. 发电机同步电动机降损节能导电装置%The Generator Synchronous Electric Motor Loss Reduction, Energy Conservation and Conduction Device

    Institute of Scientific and Technical Information of China (English)

    普朝文

    2013-01-01

      The loss reduction ,energy conservation and conduction device can reduce the losses caused by brush slip rings up to 12 .3% ~ 14 .2% ,reducing by 85 ,8% ~ 87 .7% ,can eliminate such damages as pollution ,faults and defects caused by powdered carbon arc copper foam from the brush slip rings ,can im-prove operation reliability ,safety ,limit capacity ,efficient output and service life of the generators ,can re-duce excitation losses ,service intensity and maintenance cost ,and can eliminate pollution of powdered car-bon copper foam . Therefore ,the loss reduction ,energy conservation and conduction device can enable brush excitation generators and synchronous electric motors to implement energy conservation and emis -sion reduction as well as to upgrade and to replace the older generators by the new ones .%  降损节能导电装置能把电刷滑环引起的损耗降低到12.3%~14.2%,能减少85.8%~87.7%的损耗;能消除电刷滑环产生的电弧碳粉铜沫引起的污染、故障、事故的危害,能提高发电机的运行可靠性、安全性、极限容量、效率出力、使用寿命,能减少励磁损耗、维护工作量、维护费用,能消除碳粉沫铜沫污染。因此降损节能导电装置能使有刷励磁发电机、同步电动机实现节能减排升级换代。

  8. Poverty Reduction

    OpenAIRE

    Ortiz, Isabel

    2007-01-01

    The paper reviews poverty trends and measurements, poverty reduction in historical perspective, the poverty-inequality-growth debate, national poverty reduction strategies, criticisms of the agenda and the need for redistribution, international policies for poverty reduction, and ultimately understanding poverty at a global scale. It belongs to a series of backgrounders developed at Joseph Stiglitz's Initiative for Policy Dialogue.

  9. Third-generation dual-source 70-kVp chest CT angiography with advanced iterative reconstruction in young children: image quality and radiation dose reduction

    Energy Technology Data Exchange (ETDEWEB)

    Rompel, Oliver; Janka, Rolf; Lell, Michael M.; Uder, Michael; Hammon, Matthias [University Hospital Erlangen, Department of Radiology, Erlangen (Germany); Gloeckler, Martin; Dittrich, Sven [University Hospital Erlangen, Department of Pediatric Cardiology, Erlangen (Germany); Cesnjevar, Robert [University Hospital Erlangen, Department of Pediatric Cardiac Surgery, Erlangen (Germany)

    2016-04-15

    Many technical updates have been made in multi-detector CT. To evaluate image quality and radiation dose of high-pitch second- and third-generation dual-source chest CT angiography and to assess the effects of different levels of advanced modeled iterative reconstruction (ADMIRE) in newborns and children. Chest CT angiography (70 kVp) was performed in 42 children (age 158 ± 267 days, range 1-1,194 days). We evaluated subjective and objective image quality, and radiation dose with filtered back projection (FBP) and different strength levels of ADMIRE. For comparison were 42 matched controls examined with a second-generation 128-slice dual-source CT-scanner (80 kVp). ADMIRE demonstrated improved objective and subjective image quality (P <.01). Mean signal/noise, contrast/noise and subjective image quality were 11.9, 10.0 and 1.9, respectively, for the 80 kVp mode and 11.2, 10.0 and 1.9 for the 70 kVp mode. With ADMIRE, the corresponding values for the 70 kVp mode were 13.7, 12.1 and 1.4 at strength level 2 and 17.6, 15.6 and 1.2 at strength level 4. Mean CTDI{sub vol}, DLP and effective dose were significantly lower with the 70-kVp mode (0.31 mGy, 5.33 mGy*cm, 0.36 mSv) compared to the 80-kVp mode (0.46 mGy, 9.17 mGy*cm, 0.62 mSv; P <.01). The third-generation dual-source CT at 70 kVp provided good objective and subjective image quality at lower radiation exposure. ADMIRE improved objective and subjective image quality. (orig.)

  10. Cross-cultural development of an item list for computer-adaptive testing of fatigue in oncological patients

    Directory of Open Access Journals (Sweden)

    Oberguggenberger Anne S

    2011-03-01

    Full Text Available Abstract Introduction Within an ongoing project of the EORTC Quality of Life Group, we are developing computerized adaptive test (CAT measures for the QLQ-C30 scales. These new CAT measures are conceptualised to reflect the same constructs as the QLQ-C30 scales. Accordingly, the Fatigue-CAT is intended to capture physical and general fatigue. Methods The EORTC approach to CAT development comprises four phases (literature search, operationalisation, pre-testing, and field testing. Phases I-III are described in detail in this paper. A literature search for fatigue items was performed in major medical databases. After refinement through several expert panels, the remaining items were used as the basis for adapting items and/or formulating new items fitting the EORTC item style. To obtain feedback from patients with cancer, these English items were translated into Danish, French, German, and Spanish and tested in the respective countries. Results Based on the literature search a list containing 588 items was generated. After a comprehensive item selection procedure focusing on content, redundancy, item clarity and item difficulty a list of 44 fatigue items was generated. Patient interviews (n = 52 resulted in 12 revisions of wording and translations. Discussion The item list developed in phases I-III will be further investigated within a field-testing phase (IV to examine psychometric characteristics and to fit an item response theory model. The Fatigue CAT based on this item bank will provide scores that are backward-compatible to the original QLQ-C30 fatigue scale.

  11. Scientific Items in Cyprus Turkish Tales

    Directory of Open Access Journals (Sweden)

    Sevilay Atmaca

    2013-05-01

    Full Text Available Folk literature, which is a production of daily life experiences transferred from mouth to mouth, encompasses many types such as epic, legend, folk poetry, mania, laments, songs, riddles, tales, folk story, anecdote, proverbs, idioms, rhymes, and etc. These products, which represent the oral tradition of the people, transfer numerous information regarding the life experiences, beliefs, and values of their communities to the next generation. Tales are more attractive since they depict extraordinary events and because of these characteristics they are very didactic. These are some reasons why tales have a very significant place in Turkish folk literature. People have documented tales successfully transferring from a nomadic life to a settled one. This study attempts to determine the scientific elements in Cyprus Turkish Tales, as sample in the scope of the Turkish Tales, through content analysis. Researchers in this study will examine the themes in the selected tales such as “Earth and Cosmos”, “Physical Event”, “Matter and Change”, and “Living Organisms and Life”. They will also provide a code-list according to the themes found in the tales. Researchers will do a content analysis in relation to the themes and code-listing activities in “Cyprus Turkish Tales” collected by Mustafa Gökçeoğlu, a well-known Cyprus Turkish folk literature writer. It is seen from the research that living organism and life (f: 25 and matter and change (f: 24 themes have very abundant coded. It is followed with an orderly physical events theme (f: 13 and earth and cosmos theme (f: 6. As a result, it is seen that in samples which are taken from Turkish Cypriot Tales, scientific items are widely used. It is believed that the results of the study will give different perspectives to Turkish Language, literature, science-technology, and classroom teacher providing them with interdisciplinary and rich materials.

  12. Contrast volume reduction using third generation dual source computed tomography for the evaluation of patients prior to transcatheter aortic valve implantation

    Energy Technology Data Exchange (ETDEWEB)

    Bittner, Daniel O. [University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Department of Internal Medicine 2 (Cardiology), Erlangen (Germany); Harvard Medical School, Cardiac MR PET CT Program, Massachusetts General Hospital, Boston, MA (United States); Arnold, Martin; Klinghammer, Lutz; Schuhbaeck, Annika; Hell, Michaela M.; Muschiol, Gerd; Gauss, Soeren; Achenbach, Stephan; Marwan, Mohamed [University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Department of Internal Medicine 2 (Cardiology), Erlangen (Germany); Lell, Michael; Uder, Michael [University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Department of Radiology, Erlangen (Germany); Hoffmann, Udo [Harvard Medical School, Cardiac MR PET CT Program, Massachusetts General Hospital, Boston, MA (United States)

    2016-12-15

    Chronic renal failure is common in patients referred for transcatheter aortic valve implantation (TAVI). CT angiography is recommended and provides crucial information prior to TAVI. We evaluated the feasibility of a reduced contrast volume protocol for pre-procedural CT imaging. Forty consecutive patients were examined with prospectively ECG-triggered high-pitch spiral acquisition using a novel third-generation dual-source CT system; 38 ml contrast agent was used. Image quality was graded on a visual scale (1-4). Contrast attenuation was measured at the level of the aortic root and at the iliac bifurcation. Mean patient age was 82 ± 6 years (23 males; 58 %). Mean attenuation/average image quality was 285 ± 60 HU/1.5 at the aortic annulus compared to 289 ± 74 HU/1.8 at the iliac bifurcation (p = 0.77/p = 0.29). Mean estimated effective radiation dose was 2.9 ± 0.3 mSv. A repeat acquisition was necessary in one patient due to image quality. Out of the 35 patients who underwent TAVI, 31 (89 %) patients had no or mild aortic regurgitation. Thirty-two (91 %) patients were discharged successfully. Pre-procedural CTA with a total of 38 ml contrast volume is feasible and clinically useful, using third-generation dual-source CT, allowing comprehensive imaging for procedural success. (orig.)

  13. Direct determination of arsenic in soil samples by fast pyrolysis-chemical vapor generation using sodium formate as a reductant followed by nondispersive atomic fluorescence spectrometry

    Science.gov (United States)

    Duan, Xuchuan; Zhang, Jingya; Bu, Fanlong

    2015-09-01

    This new study shows for the first time that sodium formate can react with trace arsenic to form volatile species via fast pyrolysis - chemical vapor generation. We found that the presence of thiourea greatly enhanced the generation efficiency and eliminated the interference of copper. We studied the reaction temperature, the volume of sodium formate, the reaction acidity, and the carried argon rate using nondispersive atomic fluorescence spectrometry. Under optimal conditions of T = 500 °C, the volumes of 30% sodium formate and 10% thiourea were 0.2 ml and 0.05 ml, respectively. The carrier argon rate was 300 ml min- 1 and the detection limit and precision of arsenic were 0.39 ng and 3.25%, respectively. The amount of arsenic in soil can be directly determined by adding trace amount of hydrochloric acid as a decomposition reagent without any sample pretreatment. The method was successfully applied to determine trace amount of arsenic in two soil-certified reference materials (GBW07453 and GBW07450), and the results were found to be in agreement with certified reference values.

  14. NHRIC (National Health Related Items Code)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The National Health Related Items Code (NHRIC) is a system for identification and numbering of marketed device packages that is compatible with other numbering...

  15. NHRIC (National Health Related Items Code)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The National Health Related Items Code (NHRIC) is a system for identification and numbering of marketed device packages that is compatible with other numbering...

  16. National Hospice Item Set (HIS) data

    Data.gov (United States)

    U.S. Department of Health & Human Services — This data set includes the national averages (mean) for quality measure scores of Medicare-certified hospice agencies calculated from the Hospice Item Set (HIS) for...

  17. The Analysis of The Multiple Choice Item

    Institute of Scientific and Technical Information of China (English)

    曹吴惠

    2009-01-01

    In this article, the author analyzes in detail the advantages, disadvantages and forming of the multiple choice item in examinations. On its basis, the author also exploree some aspects the teacher should pay attention to while setting an examination paper.

  18. Extending Item Response Theory to Online Homework

    CERN Document Server

    Kortemeyer, Gerd

    2014-01-01

    Item Response Theory becomes an increasingly important tool when analyzing ``Big Data'' gathered from online educational venues. However, the mechanism was originally developed in traditional exam settings, and several of its assumptions are infringed upon when deployed in the online realm. For a large enrollment physics course for scientists and engineers, the study compares outcomes from IRT analyses of exam and homework data, and then proceeds to investigate the effects of each confounding factor introduced in the online realm. It is found that IRT yields the correct trends for learner ability and meaningful item parameters, yet overall agreement with exam data is moderate. It is also found that learner ability and item discrimination is over wide ranges robust with respect to model assumptions and introduced noise, less so than item difficulty.

  19. Basic Stand Alone Carrier Line Items PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Carrier Line Items Public Use Files (PUF) with information from Medicare Carrier claims. The CMS BSA Carrier Line...

  20. Calorimetry of low mass Pu239 items

    Energy Technology Data Exchange (ETDEWEB)

    Cremers, Teresa L [Los Alamos National Laboratory; Sampson, Thomas E [Los Alamos National Laboratory

    2010-01-01

    Calorimetric assay has the reputation of providing the highest precision and accuracy of all nondestructive assay measurements. Unfortunately, non-destructive assay practitioners and measurement consumers often extend, inappropriately, the high precision and accuracy of calorimetric assay to very low mass items. One purpose of this document is to present more realistic expectations for the random uncertainties associated with calorimetric assay for weapons grade plutonium items with masses of 200 grams or less.

  1. New developments in reprocessing semicritical items.

    Science.gov (United States)

    Rutala, William A; Weber, David J

    2013-05-01

    Semicritical medical devices are defined as items that come into contact with mucous membranes or nonintact skin (eg, gastrointestinal endoscopes). Such medical devices require minimally high-level disinfection. Because many of these items are temperature sensitive, low-temperature chemical methods must be used rather than steam sterilization. Strict adherence to current guidelines is required because more outbreaks have been linked to inadequately cleaned or disinfected endoscopes undergoing high-level disinfection than any other medical device.

  2. A Review of Test Item Types

    Science.gov (United States)

    2008-03-06

    for integration with the CAT- ASVAB as it exists now. The CAT-ASVAB currently employs only dichotomously scored items using the 3 parameter logistic ...model ( 3PL ; Lord & Novick, 1968). IRT models appropriate for polytomously scored items (e.g., Muraki, 1997) are available, and mixing of models is not...problematic within the IRT framework per se. Nevertheless, the current CAT-ASVAB infrastructure is configured to work with the 3PL model only, and

  3. Residue Derived Fuels as an Alternative Fuel for the Hellenic Power Generation Sector and their Potential for Emissions ReductionConstantinos S. Psomopoulos

    Directory of Open Access Journals (Sweden)

    Constantinos S. Psomopoulos

    2014-09-01

    Full Text Available The European Union Landfill Directive (1999/31 EC promotes more environmental friendly waste management options, by reducing the amount of wastes and more specific of biodegradable wastes, disposed of in landfills. The EU member states are adopting the mechanical-biological treatment process for municipal solid waste and non-hazardous industrial wastes to comply with the abovementioned Directive's targets on landfill diversion, and produce waste derived fuels such as refuse derived fuel and solid recovered fuel. Waste derived fuels present high calorific values depending on their synthesis and are being used both in dedicated waste-to-energy plants and as fuel substitutes in industrial processes. In this paper the refuse derived fuel and solid recovered fuel production and utilisation options in European Union are presented, and the possibilities in Greece based on the waste production and National Plan for Waste Management of the Ministry of Environment is attempted. The existing and ongoing studies on co-combustion and co-gasification with brown coal support the use of refuse derived fuel and solid recovered fuel as fuel on Hellenic Power Sector, adopting in the existing lignite power plants adequate Air Pollution Control systems. If the co-combustion or co-gasification of these alternative fuels is adopted from the Hellenic Power Sector a reduction on emissions is expected that cannot be neglected.

  4. Catalytic hydrolysis of urea with fly ash for generation of ammonia in a batch reactor for flue gas conditioning and NOx reduction

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, J.N.; Gangadharan, P.; Patwardhan, A.V.; Meikap, B.C. [Indian Institute of Technology, Kharagpur (India). Dept. of Chemical Engineering

    2009-01-15

    Ammonia is a highly volatile noxious material with adverse physiological effects, which become intolerable even at very low concentrations and present substantial environmental and operating hazards and risk. Yet ammonia has long been known to be used for feedstock of flue gas conditioning and NOx reduction. Urea as the source of ammonia for the production of ammonia has the obvious advantages that no ammonia shipping, handling, and storage is required. The process of this invention minimizes the risks and hazards associated with the transport, storage, and use of anhydrous and aqueous ammonia. Yet no such rapid urea conversion process is available as per requirement of high conversion in shorter time, so here we study the catalytic hydrolysis of urea for fast conversion in a batch reactor. The catalyst used in this study is fly ash, a waste material originating in great amounts in combustion processes. A number of experiments were carried out in a batch reactor at different catalytic doses, temperatures, times, and at a constant concentration of urea solution 10% by weight, and equilibrium and kinetic studies have been made.

  5. Vending Machines: A Narrative Review of Factors Influencing Items Purchased.

    Science.gov (United States)

    Hua, Sophia V; Ickovics, Jeannette R

    2016-10-01

    Vending machines are a ubiquitous part of our food environments. Unfortunately, items found in vending machines tend to be processed foods and beverages high in salt, sugar, and/or fat. The purpose of this review is to describe intervention and case studies designed to promote healthier vending purchases by consumers and identify which manipulations are most effective. All studies analyzed were intervention or case studies that manipulated vending machines and analyzed sales or revenue data. This literature review is limited to studies conducted in the United States within the past 2 decades (ie, 1994 to 2015), regardless of study population or setting. Ten articles met these criteria based on a search conducted using PubMed. Study manipulations included price changes, increase in healthier items, changes to the advertisements wrapped around vending machines, and promotional signs such as a stoplight system to indicate healthfulness of items and to remind consumers to make healthy choices. Overall, seven studies had manipulations that resulted in statistically significant positive changes in purchasing behavior. Two studies used manipulations that did not influence consumer behavior, and one study was equivocal. Although there was no intervention pattern that ensured changes in purchasing, price reductions were most effective overall. Revenue from vending sales did not change substantially regardless of intervention, which will be important to foster initiation and sustainability of healthier vending. Future research should identify price changes that would balance healthier choices and revenue as well as better marketing to promote purchase of healthier items. Copyright © 2016 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  6. Volume reduction philosophy and techniques in use or planned

    Energy Technology Data Exchange (ETDEWEB)

    Row, T.H.

    1984-01-01

    Siting and development of nuclear waste disposal facilities is an expensive task. In the private sector, such developments face siting and licensing issues, public intervention, and technology challenges. The United States Department of Energy (DOE) faces similar challenges in the management of waste generated by the research and production facilities. Volume reduction can be used to lengthen the service life of existing facilities. A wide variety of volume reduction techniques are applied to different waste forms. Compressible waste is compacted into drums, cardboard and metal boxes, and the loaded drums are supercompacted into smaller units. Large metallic items are size-reduced and melted for recycle or sent to shallow land burial. Anaerobic digestion is a process that can reduce cellulosic and animal wastes by 80%. Incinerators of all types have been investigated for application to nuclear wastes and a number of installations operate or are constructing units for low-level and transuranic solid and liquid combustibles. Technology may help solve many of the problems in volume reduction, but the human element also has an important part in solving the puzzle. Aggressive educational campaigns at two sites have proved very successful in reducing waste generation. This overview of volume reduction is intended to transfer the current information from many DOE facilities. 44 references, 85 figures, 5 tables.

  7. Investigating Item Exposure Control Methods in Computerized Adaptive Testing

    Science.gov (United States)

    Ozturk, Nagihan Boztunc; Dogan, Nuri

    2015-01-01

    This study aims to investigate the effects of item exposure control methods on measurement precision and on test security under various item selection methods and item pool characteristics. In this study, the Randomesque (with item group sizes of 5 and 10), Sympson-Hetter, and Fade-Away methods were used as item exposure control methods. Moreover,…

  8. 15 CFR 734.3 - Items subject to the EAR.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Items subject to the EAR. 734.3... EXPORT ADMINISTRATION REGULATIONS § 734.3 Items subject to the EAR. (a) Except for items excluded in paragraph (b) of this section, the following items are subject to the EAR: (1) All items in the...

  9. Speckle reduction by combination of digital filter and optical suppression in a modified Gerchberg-Saxton algorithm computer-generated hologram.

    Science.gov (United States)

    Chen, Chien-Yue; Deng, Qing-Long; Wu, Pei-Jung; Lin, Bor-Shyh; Chang, Hsuan T; Hwang, Hone-Ene; Huang, Guan-Syun

    2014-09-20

    A speckleless illuminated modified-Gerchberg-Saxton-algorithm-type computer-generated hologram, which adopts a lower frequency of the iterative algorithm and calculation time, is proposed to code a hologram with two signals and position a multiplexing phase-only function, which can reconstruct the left and the right viewing holograms on the pupillary-distance position after the decryption and still maintain the content with high contrast and definition. The reconstructed image quality presents root mean square error of 0.03, with a diffraction efficiency of 87%, and signal-to-noise ratio of 8 dB after the analysis. Furthermore, two denoising techniques for the digital filter and optical suppression are combined, in which the speckle suppression with pseudorandom phase modulation and a rotating diffuser are utilized for successfully reducing the speckle contrast, which was reduced to below 4%. The goal was to reduce visual fatigue for the viewers.

  10. Automated tube voltage selection for radiation dose and contrast medium reduction at coronary CT angiography using 3{sup rd} generation dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Stefanie [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Wichmann, Julian L. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Schoepf, U.J. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Poole, Zachary B.; Varga-Szemes, Akos; De Cecco, Carlo N. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Canstein, Christian [Siemens Medical Solutions, Malvern, PA (United States); Caruso, Damiano [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Rome (Italy); Bamberg, Fabian; Nikolaou, Konstantin [Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2016-10-15

    To investigate the relationship between automated tube voltage selection (ATVS) and body mass index (BMI) and its effect on image quality and radiation dose of coronary CT angiography (CCTA). We evaluated 272 patients who underwent CCTA with 3{sup rd} generation dual-source CT (DSCT). Prospectively ECG-triggered spiral acquisition was performed with automated tube current selection and advanced iterative reconstruction. Tube voltages were selected by ATVS (70-120 kV). BMI, effective dose (ED), and vascular attenuation in the coronary arteries were recorded. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Five-point scales were used for subjective image quality analysis. Image quality was rated good to excellent in 98.9 % of examinations without significant differences for proximal and distal attenuation (all p ≥.0516), whereas image noise was rated significantly higher at 70 kV compared to ≥100 kV (all p <.0266). However, no significant differences were observed in SNR or CNR at 70-120 kV (all p ≥.0829). Mean ED at 70-120 kV was 1.5 ± 1.2 mSv, 2.4 ± 1.5 mSv, 3.6 ± 2.7 mSv, 5.9 ± 4.0 mSv, 7.9 ± 4.2 mSv, and 10.7 ± 4.1 mSv, respectively (all p ≤.0414). Correlation analysis showed a moderate association between tube voltage and BMI (r =.639). ATVS allows individual tube voltage adaptation for CCTA performed with 3{sup rd} generation DSCT, resulting in significantly decreased radiation exposure while maintaining image quality. (orig.)

  11. An emotional functioning item bank of 24 items for computerized adaptive testing (CAT) was established

    DEFF Research Database (Denmark)

    Petersen, Morten Aa.; Gamper, Eva-Maria; Costantini, Anna

    2016-01-01

    OBJECTIVE: To improve measurement precision, the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Group is developing an item bank for computerized adaptive testing (CAT) of emotional functioning (EF). The item bank will be within the conceptual framework...... of the widely used EORTC Quality of Life questionnaire (QLQ-C30). STUDY DESIGN AND SETTING: On the basis of literature search and evaluations by international samples of experts and cancer patients, 38 candidate items were developed. The psychometric properties of the items were evaluated in a large...... international sample of cancer patients. This included evaluations of dimensionality, item response theory (IRT) model fit, differential item functioning (DIF), and of measurement precision/statistical power. RESULTS: Responses were obtained from 1,023 cancer patients from four countries. The evaluations showed...

  12. Psychometric Changes on Item Difficulty Due to Item Review by Examinees

    Directory of Open Access Journals (Sweden)

    Elena C. Papanastasiou

    2015-01-01

    Full Text Available If good measurement depends in part on the estimation of accurate item characteristics, it is essential that test developers become aware of discrepancies that may exist on the item parameters before and after item review. The purpose of this study was to examine the answer changing patterns of students while taking paper-and-pencil multiple choice exams, and to examine how these changes affect the estimation of item difficulty parameters. The results of this study have shown that item review by examinees does produce some changes to the examinee ability estimates and to the item difficulty parameters. In addition, these effects are more pronounced in shorter tests than in longer tests. In turn, these small changes produce larger effects when estimating the changes in the information values of each student's test score.

  13. A supplier-selection model with classification and joint replenishment of inventory items

    Science.gov (United States)

    Mohammaditabar, Davood; Hassan Ghodsypour, Seyed

    2016-06-01

    Since inventory costs are closely related to suppliers, many models in the literature have selected the suppliers and also allocated orders, simultaneously. Such models usually consider either a single inventory item or multiple inventory items which have independent holding and ordering costs. However, in practice, ordering multiple items from the same supplier leads to a reduction in ordering costs. This paper presents a model in capacity-constrained supplier-selection and order-allocation problem, which considers the joint replenishment of inventory items with a direct grouping approach. In such supplier-selection problems, the following items are considered: a fixed major ordering cost to each supplier, which is independent from the items in the order; a minor ordering cost for each item ordered to each supplier; and the inventory holding and purchasing costs. To solve the developed NP-hard problem, a simulated annealing algorithm was proposed and then compared to a modified genetic algorithm of the literature. The numerical example represented that the number of groups and selected suppliers were reduced when the major ordering cost increased in comparison to other costs. There were also more savings when the number of groups was determined by the model in comparison to predetermined number of groups or no grouping scenarios.

  14. Reduction of the off-flavor volatile generated by the yogurt starter culture including Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus in soymilk.

    Science.gov (United States)

    Kaneko, Daisuke; Igarashi, Toshinori; Aoyama, Kenji

    2014-02-19

    Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus establish a symbiotic relationship in milk; however, S. thermophilus predominantly grows in soymilk. This study determined that excess diacetyl was notably generated mainly by S. thermophilus in soymilk, and this flavor compound created an unpleasant odor in fermented soymilk. The addition of l-valine to soymilk reduced the amount of diacetyl and increased the levels of acetoin during fermentation by S. thermophilus . In addition, it was found that the expression of the ilvC gene was repressed and that of the als and aldB genes was stimulated in S. thermophilus by l-valine. Sensory evaluations with the triangle difference test and a preference test showed that the soymilk fermented with l-valine was significantly preferred compared with that without l-valine. In this study, we successfully controlled the metabolic flux of S. thermophilus in soymilk and produced more favorable fermented soymilk without the use of genetically modified lactic acid bacteria strains.

  15. Alternate item types: continuing the quest for authentic testing.

    Science.gov (United States)

    Wendt, Anne; Kenny, Lorraine E

    2009-03-01

    Many test developers suggest that multiple-choice items can be used to evaluate critical thinking if the items are focused on measuring higher order thinking ability. The literature supports the use of alternate item types to assess additional competencies, such as higher level cognitive processing and critical thinking, as well as ways to allow examinees to demonstrate their competencies differently. This research study surveyed nurses after taking a test composed of alternate item types paired with multiple-choice items. The participants were asked to provide opinions regarding the items and the item formats. Demographic information was asked. In addition, information was collected as the participants responded to the items. The results of this study reveal that the participants thought that, in general, the items were more authentic and allowed them to demonstrate their competence better than multiple-choice items did. Further investigation into the optimal blend of alternate items and multiple-choice items is needed.

  16. A Novel Approach for Association Rule Mining using Pattern Generation

    Directory of Open Access Journals (Sweden)

    Deepa S. Deshpande

    2014-10-01

    Full Text Available Data mining has become a process of significant interest in recent years due to explosive rate of the accumulation of data. It is used to discover potentially valuable implicit knowledge from the large transactional databases. Association rule mining is one of the well known techniques of data mining. It typically aims at discovering associations between attributes in the large databases. The first and the most influential traditional algorithm for association rule discovery is Apriori. Multiple scans of database, generation of large number of candidates item set and discovery of interesting rules are the main challenging issues for the improvement of Apriori algorithm. Therefore in order to decrease the multiple scanning of database, a new method of association rule mining using pattern generation is proposed in this paper. This method involves three steps. First, patterns are generated using items from the transaction database. Second, frequent item set is obtained using these patterns. Finally association rules are derived. The performance of this method is evaluated with the traditional Apriori algorithm. It shows that behavior of the proposed method is much more similar to Apriori algorithm with less memory space and reduction in multiple times scanning of database. Thus it is more efficient than the traditional Apriori algorithm.

  17. Dynamic programming for reduction of fuel consumption in a photovoltaic/wind/diesel generating system; Doteki keikakuho ni yoru taiyoko/furyoku/diesel hatsuden system no nenryo shohiryo no sakugen

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, K.; Kenmoku, Y.; Sakakibara, T. [Toyohashi University of Technology, Aichi (Japan); Nakagawa, S. [Maizuru National College of Technology, Kyoto (Japan); Kawamoto, T. [Shizuoka University, Shizuoka (Japan)

    1997-11-25

    Dynamic programming is employed in the study of the operation of the diesel engine in a photovoltaic/wind-force/diesel-engine power generating system, which aims at reduction in the system fuel consumption and at determining an optimum system constitution. The parameters set in this system are the photovoltaic/wind-force supply rate, photovoltaic/wind-force power generation ratio, and battery capacity. An island in Ise Bay, with an annual load power of approximately 1.59-million kWh and mean daily load power of approximately 4336kWh is assumed as the location for the system. Observation data of Ommaezaki Weather Station are utilized for the calculation of the amount of photovoltaic/wind-force power generation. It is found as the result that the fuel consumption of the diesel engine in this system decreases to 82-84% when the natural energy supply rate is 20%. It is also found that the fuel consumption of the system records the minimum at a photovoltaic/wind-force ratio of 60/40, irrespective of the battery capacity or natural energy supply rate, and this ratio is the optimum ratio. 3 refs., 9 figs., 1 tab.

  18. Measuring response styles in Likert items.

    Science.gov (United States)

    Böckenholt, Ulf

    2017-03-01

    The recently proposed class of item response tree models provides a flexible framework for modeling multiple response processes. This feature is particularly attractive for understanding how response styles may affect answers to attitudinal questions. Facilitating the disassociation of response styles and attitudinal traits, item response tree models can provide powerful process tests of how different response formats may affect the measurement of substantive traits. In an empirical study, 3 response formats were used to measure the 2-dimensional Personal Need for Structure traits. Different item response tree models are proposed to capture the response styles for each of the response formats. These models show that the response formats give rise to similar trait measures but different response-style effects. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  19. Physics Items and Student's Performance at Enem

    CERN Document Server

    Gonçalves, Wanderley P

    2013-01-01

    The Brazilian National Assessment of Secondary Education (ENEM, Exame Nacional do Ensino M\\'edio) has changed in 2009: from a self-assessment of competences at the end of high school to an assessment that allows access to college and student financing. From a single general exam, now there are tests in four areas: Mathematics, Language, Natural Sciences and Social Sciences. A new Reference Matrix is build with components as cognitive domains, competencies, skills and knowledge objects; also, the methodological framework has changed, using now Item Response Theory to provide scores and allowing longitudinal comparison of results from different years, providing conditions for monitoring high school quality in Brazil. We present a study on the issues discussed in Natural Science Test of ENEM over the years 2009, 2010 and 2011. Qualitative variables are proposed to characterize the items, and data from students' responses in Physics items were analysed. The qualitative analysis reveals the characteristics of the ...

  20. Validation of Physics Standardized Test Items

    Science.gov (United States)

    Marshall, Jill

    2008-10-01

    The Texas Physics Assessment Team (TPAT) examined the Texas Assessment of Knowledge and Skills (TAKS) to determine whether it is a valid indicator of physics preparation for future course work and employment, and of the knowledge and skills needed to act as an informed citizen in a technological society. We categorized science items from the 2003 and 2004 10th and 11th grade TAKS by content area(s) covered, knowledge and skills required to select the correct answer, and overall quality. We also analyzed a 5000 student sample of item-level results from the 2004 11th grade exam using standard statistical methods employed by test developers (factor analysis and Item Response Theory). Triangulation of our results revealed strengths and weaknesses of the different methods of analysis. The TAKS was found to be only weakly indicative of physics preparation and we make recommendations for increasing the validity of standardized physics testing..

  1. Ordinal-To-Interval Scale Conversion Tables and National Items for the New Zealand Version of the WHOQOL-BREF.

    Science.gov (United States)

    Krägeloh, Christian U; Billington, D Rex; Hsu, Patricia Hsien-Chuan; Feng, Xuan Joanna; Medvedev, Oleg N; Kersten, Paula; Landon, Jason; Siegert, Richard J

    2016-01-01

    The World Health Organisation Quality of Life (WHOQOL) questionnaires are widely used around the world and can claim strong cross-cultural validity due to their development in collaboration with international field centres. To enhance conceptual equivalence of quality of life across cultures, optional national items are often developed for use alongside the core instrument. The present study outlines the development of national items for the New Zealand WHOQOL-BREF. Focus groups with members of the community as well as health experts discussed what constitutes quality of life in their opinion. Based on themes extracted of aspects not contained in the existing WHOQOL instrument, 46 candidate items were generated and subsequently rated for their importance by a random sample of 585 individuals from the general population. Applying importance criteria reduced these items to 24, which were then sent to another large random sample (n = 808) to be rated alongside the existing WHOQOL-BREF. A final set of five items met the criteria for national items. Confirmatory factor analysis identified four national items as belonging to the psychological domain of quality of life, and one item to the social domain. Rasch analysis validated these results and generated ordinal-to-interval conversion algorithms to allow use of parametric statistics for domain scores with and without national items.

  2. Differential item functioning due to gender between depression and anxiety items among Chilean adolescents.

    Science.gov (United States)

    Bares, Cristina; Andrade, Fernando; Delva, Jorge; Grogan-Kaylor, Andrew; Kamata, Akihito

    2012-07-01

    Although much is known about the higher prevalence of anxiety and depressive disorders among adolescent females, less is known about the differential item endorsement due to gender in items of scales commonly used to measure anxiety and depression. We conducted a study to examine if adolescent males and females from Chile differed on how they endorsed the items of the Youth Self Report (YSR) anxious/depressed problem scale. We used data from a cross-sectional sample consisting of 925 participants (mean age = 14, SD 1.3, 49% females) of low to lower-middle socioeconomic status. A two-parameter logistic (2PL) IRT DIF model was fit. s revealed differential item functioning (DIF) by gender for six of the 13 items, with adolescent females being more likely to endorse a depression item while males were found more likely to endorse anxiety items. Findings suggest that items found in commonly used measures of anxiety and depression symptoms may not equally capture the true levels of these behavioural problems in adolescent males and females. Given the high levels of mental disorders in Chile and the surrounding countries, further attention should be focused on increasing the number of empirical studies examining potential gender differences in the assessment of mental health problems among Latin American populations to better aid our understanding of the phenomenology and determinants of these problems in the region.

  3. Developing Multidimensional Likert Scales Using Item Factor Analysis: The Case of Four-Point Items

    Science.gov (United States)

    Asún, Rodrigo A.; Rdz-Navarro, Karina; Alvarado, Jesús M.

    2016-01-01

    This study compares the performance of two approaches in analysing four-point Likert rating scales with a factorial model: the classical factor analysis (FA) and the item factor analysis (IFA). For FA, maximum likelihood and weighted least squares estimations using Pearson correlation matrices among items are compared. For IFA, diagonally weighted…

  4. Evaluating Item Discrimination Power of WHOQOL-BREF from an Item Response Model Perspectives

    Science.gov (United States)

    Lin, Ting Hsiang; Yao, Grace

    2009-01-01

    Quality of life (QOL) has become an important component of health. By using the methodology of psychometric theory, we examine the item properties of the WHOQOL-BRIEF. Samejima's graded response model with natural metrics of the logistic response function was fitted. The results showed items with negative natures were less discriminating. Items…

  5. Application of Unidimensional Item Response Models to Tests with Items Sensitive to Secondary Dimensions

    Science.gov (United States)

    Zhang, Bo

    2008-01-01

    In this research, the author addresses whether the application of unidimensional item response models provides valid interpretation of test results when administering items sensitive to multiple latent dimensions. Overall, the present study found that unidimensional models are quite robust to the violation of the unidimensionality assumption due…

  6. Are Inferential Reading Items More Susceptible to Cultural Bias than Literal Reading Items?

    Science.gov (United States)

    Banks, Kathleen

    2012-01-01

    The purpose of this article is to illustrate a seven-step process for determining whether inferential reading items were more susceptible to cultural bias than literal reading items. The seven-step process was demonstrated using multiple-choice data from the reading portion of a reading/language arts test for fifth and seventh grade Hispanic,…

  7. Item Structure as a Determinant of Item Difficulty in Verbal Analogies

    Science.gov (United States)

    Ace, Merle C.; Dawis, Rene V.

    1973-01-01

    Because no previous study was found in which both blank position in the item stem and positional placement of the correct response were studied simultaneously, it was decided to investigate the influence of these two factors, alone and in combination, on the difficulty level of verbal analogy items. (Authors)

  8. Secondary Item Procurement Lead Time Study.

    Science.gov (United States)

    1984-03-01

    NONEhhhhhh % I - 15 III& 1-- -NAION&°I° oI Ai OF .° NAIU REUONF TEST CANA -~~ 7 .. SECONDARY ITEM PROCUREMENT LEAD TIME STUDY __ LOGISTICS SYSTEMS...ASSISTANT SECRETARY OF THE AIR FORCE (RD&L) DIRECTOR, DEFENSE LOGISTICS AGENCY SUBJECT: Secondary Item Procurement Lead Time Study A recent report by the...determination of procurement lead time. A plan for the study is enclosed. In order to achieve the objectives of the procurement lead time study as well as the

  9. MULTI-ITEM FAIR EXCHANGE SCHEME

    Institute of Scientific and Technical Information of China (English)

    Zheng Dong; Chen Kefei

    2002-01-01

    As more business is conduced over the Internet, the fair exchange problem assumes increasing importance. However, the problem of multi-party fair exchange has not been studied as widely as the more fundamental problem of 2-party fair exchange. Recently, Franklin and Tsudik proposed two protocols for n-party multi-item exchange on FC'98, SUCEX-1 and SUCES-2. This paper first gives an attack on the proposed protocol SUCEX-1, then presents two protocols for multi-item exchange, one is an improved protocol of SUCEX-1, another is the extension of protocol SUCEX-2.

  10. MULTI—ITEM FAIR EXCHANGE SCHEME

    Institute of Scientific and Technical Information of China (English)

    ZhengDong; ChenKefei

    2002-01-01

    As more ubsiness is conduced over the Internet,the fair exchange problem assumes increasing importance,However,the problem of multi-party fair exchange has not been studied as widely as the more fundamental problem of 2-party fair exchange,Recently,Franklin and Tsudik proposed two protocols for n-parth multi-item exchange on FC'98,SUCEX-1 and SUCES-2,This paper first gives an attack on the proposed protocol SUCEX-1,then presents two protocols for multi-item exchange,one is an improoved protocol of SUCEX-1,another is the extension of protocol SUCEX-2.

  11. Comparison on Computed Tomography using industrial items

    DEFF Research Database (Denmark)

    Angel, Jais Andreas Breusch; De Chiffre, Leonardo

    2014-01-01

    In a comparison involving 27 laboratories from 8 countries, measurements on two common industrial items, a polymer part and a metal part, were carried out using X-ray Computed Tomography. All items were measured using coordinate measuring machines before and after circulation, with reference...... measurement uncertainties in the range 1.5–5.5 μm, showing a good stability over the 6 months of the circulation. The comparison has shown that CT measurements on the industrial parts used lie in the range 6–53 μm, with maximum values up to 158 μm....

  12. Determination of As(III) and As(V) by Flow Injection-Hydride Generation-Atomic Absorption Spectrometry via On-line Reduction of As(V) by KI

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Hansen, Elo Harald

    1997-01-01

    A volume-based flow injection (FI) procedure is described for the determination and speciation of trace inorganic arsenic, As(III) and As(V), via hydride generation-atomic absorption spectrometry (HG-AAS) of As(III). The determination of total arsenic is obtained by on-line reduction of As(V) to As...... volume is 100 mu l while the total sample consumption per assay is 1.33 ml, and the sampling frequency is 180 samples per hour. The detection limit (3 sigma) for the on-line reduction procedure was 37 ng l(-1) and at the 5.0 mu g l(-1), the relative standard deviation (RSD) was 1.1% (n=10) by calibrating...... with As(III) standards; by calibrating with As(V) standards the detection limit was 33 ng l(-1) and the RSD was 1.3% (n=10). For the selective determination of As(III) the detection limit was 111 ng l(-1) and the RSD was 0.7% (n=10) at 5.0 mu g l(-1). Both procedures are most tolerant to potential...

  13. Principles and procedures of considering item sequence effects in the development of calibrated item pools: Conceptual analysis and empirical illustration

    Directory of Open Access Journals (Sweden)

    Safir Yousfi

    2012-12-01

    Full Text Available Item responses can be context-sensitive. Consequently, composing test forms flexibly from a calibrated item pool requires considering potential context effects. This paper focuses on context effects that are related to the item sequence. It is argued that sequence effects are not necessarily a violation of item response theory but that item response theory offers a powerful tool to analyze them. If sequence effects are substantial, test forms cannot be composed flexibly on the basis of a calibrated item pool, which precludes applications like computerized adaptive testing. In contrast, minor sequence effects do not thwart applications of calibrated item pools. Strategies to minimize the detrimental impact of sequence effects on item parameters are discussed and integrated into a nomenclature that addresses the major features of item calibration designs. An example of an item calibration design demonstrates how this nomenclature can guide the process of developing a calibrated item pool.

  14. Soviet Cybernetics: Recent News Items, Number Thirteen.

    Science.gov (United States)

    Holland, Wade B.

    An issue of "Soviet Cybernetics: Recent News Items" consists of English translations of the leading recent Soviet contributions to the study of cybernetics. Articles deal with cybernetics in the 21st Century; the Soviet State Committee on Science and Technology; economic reforms in Rudnev's ministry; an interview with Rudnev; Dnepr-2; Dnepr-2…

  15. 10 CFR 74.55 - Item monitoring.

    Science.gov (United States)

    2010-01-01

    ..., except for reactor components measuring at least one meter in length and weighing in excess of 30... 10 Energy 2 2010-01-01 2010-01-01 false Item monitoring. 74.55 Section 74.55 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) MATERIAL CONTROL AND ACCOUNTING OF SPECIAL NUCLEAR MATERIAL...

  16. The Fantastic Four of Mathematics Assessment Items

    Science.gov (United States)

    Greenlees, Jane

    2011-01-01

    In this article, the author makes reference to four comic book characters to make the point that together they are a formidable team, but on their own they are vulnerable. She examines the four components of mathematics assessment items and the need for implicit instruction within the classroom for student success. Just like the "Fantastic Four"…

  17. 47 CFR 65.820 - Included items.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Included items. 65.820 Section 65.820 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) INTERSTATE RATE...) Cash working capital. The average amount of investor-supplied capital needed to provide funds for...

  18. Algorithmic test design using classical item parameters

    NARCIS (Netherlands)

    van der Linden, Willem J.; Adema, Jos J.

    1988-01-01

    Two optimalization models for the construction of tests with a maximal value of coefficient alpha are given. Both models have a linear form and can be solved by using a branch-and-bound algorithm. The first model assumes an item bank calibrated under the Rasch model and can be used, for instance, wh

  19. Estimating the Importance of Differential Item Functioning.

    Science.gov (United States)

    Rudas, Tamas; Zwick, Rebecca

    1997-01-01

    The mixture index of fit (T. Rudas et al, 1994) is used to estimate the fraction of a population for which differential item functioning (DIF) occurs, and this approach is compared to the Mantel Haenszel test of DIF. The proposed noniterative procedure provides information about data portions contributing to DIF. (SLD)

  20. Item Feature Effects in Evolution Assessment

    Science.gov (United States)

    Nehm, Ross H.; Ha, Minsu

    2011-01-01

    Despite concerted efforts by science educators to understand patterns of evolutionary reasoning in science students and teachers, the vast majority of evolution education studies have failed to carefully consider or control for item feature effects in knowledge measurement. Our study explores whether robust contextualization patterns emerge within…

  1. Bayesian item selection criteria for adaptive testing

    NARCIS (Netherlands)

    Linden, van der Wim J.

    1996-01-01

    R.J. Owen (1975) proposed an approximate empirical Bayes procedure for item selection in adaptive testing. The procedure replaces the true posterior by a normal approximation with closed-form expressions for its first two moments. This approximation was necessary to minimize the computational comple

  2. Bayesian item selection criteria for adaptive testing

    NARCIS (Netherlands)

    van der Linden, Willem J.

    1996-01-01

    R.J. Owen (1975) proposed an approximate empirical Bayes procedure for item selection in adaptive testing. The procedure replaces the true posterior by a normal approximation with closed-form expressions for its first two moments. This approximation was necessary to minimize the computational comple

  3. Estimating the Importance of Differential Item Functioning.

    Science.gov (United States)

    Rudas, Tamas; Zwick, Rebecca

    1997-01-01

    The mixture index of fit (T. Rudas et al, 1994) is used to estimate the fraction of a population for which differential item functioning (DIF) occurs, and this approach is compared to the Mantel Haenszel test of DIF. The proposed noniterative procedure provides information about data portions contributing to DIF. (SLD)

  4. Item Feature Effects in Evolution Assessment

    Science.gov (United States)

    Nehm, Ross H.; Ha, Minsu

    2011-01-01

    Despite concerted efforts by science educators to understand patterns of evolutionary reasoning in science students and teachers, the vast majority of evolution education studies have failed to carefully consider or control for item feature effects in knowledge measurement. Our study explores whether robust contextualization patterns emerge within…

  5. An Analytical Method of Identifying Biased Test Items.

    Science.gov (United States)

    Plake, Barbara S.; Hoover, H. D.

    1979-01-01

    A follow-up technique is needed to identify items contributing to items-by-groups interaction when using an ANOVA procedure to examine a test for biased items. The method described includes distribution theory for assessing level of significance and is sensitive to items at all difficulty levels. (Author/GSK)

  6. The Licensing of Negative Sensitive Items in Jordanian Arabic

    Science.gov (United States)

    Alsarayreh, Atef

    2012-01-01

    This study investigates the licensing conditions on Negative Sensitive Items (NSIs) in Jordanian Arabic (JA). JA exhibits both types of NSIs that are discussed in the literature: Negative Polarity Items (NPIs) and Negative Concord Items (NCIs). Although these two sets of items seem to form a natural class in the sense that they show certain…

  7. Development of Abbreviated Eight-Item Form of the Penn Verbal Reasoning Test

    Science.gov (United States)

    Bilker, Warren B.; Wierzbicki, Michael R.; Brensinger, Colleen M.; Gur, Raquel E.; Gur, Ruben C.

    2014-01-01

    The ability to reason with language is a highly valued cognitive capacity that correlates with IQ measures and is sensitive to damage in language areas. The Penn Verbal Reasoning Test (PVRT) is a 29-item computerized test for measuring abstract analogical reasoning abilities using language. The full test can take over half an hour to administer, which limits its applicability in large-scale studies. We previously described a procedure for abbreviating a clinical rating scale and a modified procedure for reducing tests with a large number of items. Here we describe the application of the modified method to reducing the number of items in the PVRT to a parsimonious subset of items that accurately predicts the total score. As in our previous reduction studies, a split sample is used for model fitting and validation, with cross-validation to verify results. We find that an 8-item scale predicts the total 29-item score well, achieving a correlation of .9145 for the reduced form for the model fitting sample and .8952 for the validation sample. The results indicate that a drastically abbreviated version, which cuts administration time by more than 70%, can be safely administered as a predictor of PVRT performance. PMID:24577310

  8. Measuring the quality of life in hypertension according to Item Response Theory

    Directory of Open Access Journals (Sweden)

    José Wicto Pereira Borges

    Full Text Available ABSTRACT OBJECTIVE To analyze the Miniquestionário de Qualidade de Vida em Hipertensão Arterial (MINICHAL – Mini-questionnaire of Quality of Life in Hypertension using the Item Response Theory. METHODS This is an analytical study conducted with 712 persons with hypertension treated in thirteen primary health care units of Fortaleza, State of Ceará, Brazil, in 2015. The steps of the analysis by the Item Response Theory were: evaluation of dimensionality, estimation of parameters of items, and construction of scale. The study of dimensionality was carried out on the polychoric correlation matrix and confirmatory factor analysis. To estimate the item parameters, we used the Gradual Response Model of Samejima. The analyses were conducted using the free software R with the aid of psych and mirt. RESULTS The analysis has allowed the visualization of item parameters and their individual contributions in the measurement of the latent trait, generating more information and allowing the construction of a scale with an interpretative model that demonstrates the evolution of the worsening of the quality of life in five levels. Regarding the item parameters, the items related to the somatic state have had a good performance, as they have presented better power to discriminate individuals with worse quality of life. The items related to mental state have been those which contributed with less psychometric data in the MINICHAL. CONCLUSIONS We conclude that the instrument is suitable for the identification of the worsening of the quality of life in hypertension. The analysis of the MINICHAL using the Item Response Theory has allowed us to identify new sides of this instrument that have not yet been addressed in previous studies.

  9. Managing dual warehouses with an incentive policy for deteriorating items

    Science.gov (United States)

    Yu, Jonas C. P.; Wang, Kung-Jeng; Lin, Yu-Siang

    2016-02-01

    Distributors in a supply chain usually limit their own warehouse in finite capacity for cost reduction and excess stock is held in a rent warehouse. In this study, we examine inventory control for deteriorating items in a two-warehouse setting. Assuming that there is an incentive offered by a rent warehouse that allows the rental fee to decrease over time, the objective of this study is to maximise the joint profit of the manufacturer and the distributor. An optimisation procedure is developed to derive the optimal joint economic lot size policy. Several criteria are identified to select the most appropriate warehouse configuration and inventory policy on the basis of storage duration of materials in a rent warehouse. Sensitivity analysis is done to examine the results of model robustness. The proposed model enables a manufacturer with a channel distributor to coordinate the use of alternative warehouses, and to maximise the joint profit of the manufacturer and the distributor.

  10. 17 CFR 260.7a-16 - Inclusion of items, differentiation between items and answers, omission of instructions.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Inclusion of items... INDENTURE ACT OF 1939 Formal Requirements § 260.7a-16 Inclusion of items, differentiation between items and... application, statement, or report shall contain all of the items of the form as well as the answers...

  11. Differential Item Functioning Analysis of the Science and Mathematics Items in the University Entrance Examinations in Turkey

    Science.gov (United States)

    Kalaycioglu, Dilara Bakan; Berberoglu, Giray

    2011-01-01

    This study is aimed to detect differential item functioning (DIF) items across gender groups, analyze item content for the possible sources of DIF, and eventually investigate the effect of DIF items on the criterion-related validity of the test scores in the quantitative section of the university entrance examination (UEE) in Turkey. The reason…

  12. Developing item banks for measuring pediatric generic health-related quality of life: an application of the International Classification of Functioning, Disability and Health for Children and Youth and item response theory.

    Science.gov (United States)

    Gandhi, Pranav K; Thompson, Lindsay A; Tuli, Sanjeev Y; Revicki, Dennis A; Shenkman, Elizabeth; Huang, I-Chan

    2014-01-01

    The purpose of this study was to develop item banks by linking items from three pediatric health-related quality of life (HRQoL) instruments using a mixed methodology. Secondary data were collected from 469 parents of children aged 8-16 years. The International Classification of Functioning, Disability and Health-Children and Youth (ICF-CY) served as a framework to compare the concepts of items from three HRQoL instruments. The structural validity of the individual domains was examined using confirmatory factor analyses. Samejima's Graded Response Model was used to calibrate items from different instruments. The known-groups validity of each domain was examined using the status of children with special health care needs (CSHCN). Concepts represented by the items in the three instruments were linked to 24 different second-level categories of the ICF-CY. Eight item banks representing eight unidimensional domains were created based on the linkage of the concepts measured by the items of the three instruments to the ICF-CY. The HRQoL results of CSHCN in seven out of eight domains (except personality) were significantly lower compared with children without special health care needs (p<0.05). This study demonstrates a useful approach to compare the item concepts from the three instruments and to generate item banks for a pediatric population.

  13. Self efficacy for fruit, vegetable and water intakes: Expanded and abbreviated scales from item response modeling analyses

    Directory of Open Access Journals (Sweden)

    Cullen Karen W

    2010-03-01

    Full Text Available Abstract Objective To improve an existing measure of fruit and vegetable intake self efficacy by including items that varied on levels of difficulty, and testing a corresponding measure of water intake self efficacy. Design Cross sectional assessment. Items were modified to have easy, moderate and difficult levels of self efficacy. Classical test theory and item response modeling were applied. Setting One middle school at each of seven participating sites (Houston TX, Irvine CA, Philadelphia PA, Pittsburg PA, Portland OR, rural NC, and San Antonio TX. Subjects 714 6th grade students. Results Adding items to reflect level (low, medium, high of self efficacy for fruit and vegetable intake achieved scale reliability and validity comparable to existing scales, but the distribution of items across the latent variable did not improve. Selecting items from among clusters of items at similar levels of difficulty along the latent variable resulted in an abbreviated scale with psychometric characteristics comparable to the full scale, except for reliability. Conclusions The abbreviated scale can reduce participant burden. Additional research is necessary to generate items that better distribute across the latent variable. Additional items may need to tap confidence in overcoming more diverse barriers to dietary intake.

  14. Scoring best-worst data in unbalanced many-item designs, with applications to crowdsourcing semantic judgments.

    Science.gov (United States)

    Hollis, Geoff

    2017-05-27

    Best-worst scaling is a judgment format in which participants are presented with a set of items and have to choose the superior and inferior items in the set. Best-worst scaling generates a large quantity of information per judgment because each judgment allows for inferences about the rank value of all unjudged items. This property of best-worst scaling makes it a promising judgment format for research in psychology and natural language processing concerned with estimating the semantic properties of tens of thousands of words. A variety of different scoring algorithms have been devised in the previous literature on best-worst scaling. However, due to problems of computational efficiency, these scoring algorithms cannot be applied efficiently to cases in which thousands of items need to be scored. New algorithms are presented here for converting responses from best-worst scaling into item scores for thousands of items (many-item scoring problems). These scoring algorithms are validated through simulation and empirical experiments, and considerations related to noise, the underlying distribution of true values, and trial design are identified that can affect the relative quality of the derived item scores. The newly introduced scoring algorithms consistently outperformed scoring algorithms used in the previous literature on scoring many-item best-worst data.

  15. Differential Item Functioning on the International Personality Item Poolâ s Neuroticism Scale

    OpenAIRE

    McBride, Nadine LeBarron

    2008-01-01

    As use of the public-domain International Personality Item Pool (IPIP) scales has grown significantly over the past decade (Goldberg, Johnson, Eber, Hogan, Ashton, Cloninger, & Gough, 2006) research on the psychometric properties of the items and scales have become increasingly important. This research study examines the IPIP scale constructed to measure the Five Factor Model (FFM) domain of Neuroticism (as measured by the NEO-PI-R) for occurrences of differential functioning a...

  16. Item Screening in Graphical Loglinear Rasch Models

    DEFF Research Database (Denmark)

    Kreiner, Svend; Christensen, Karl Bang

    2011-01-01

    the initial item analysis may disclose a great deal of spurious and misleading evidence of DIF and local dependence that has to disposed of during the modelling procedure. Like graphical models, graphical loglinear Rasch models possess Markov properties that are useful during the statistical analysis......In behavioural sciences, local dependence and DIF are common, and purification procedures that eliminate items with these weaknesses often result in short scales with poor reliability. Graphical loglinear Rasch models (Kreiner & Christensen, in Statistical Methods for Quality of Life Studies, ed....... by M. Mesbah, F.C. Cole & M.T. Lee, Kluwer Academic, pp. 187–203, 2002) where uniform DIF and uniform local dependence are permitted solve this dilemma by modelling the local dependence and DIF. Identifying loglinear Rasch models by a stepwise model search is often very time consuming, since...

  17. Teoria de la respuesta al item

    OpenAIRE

    2009-01-01

    A preocupação com medidas de traços psicológicos é antiga, sendo que muitos estudos e propostas de métodos foram desenvolvidos no sentido de alcançar este objetivo. Entre os trabalhos propostos, destaca-se a Teoria da Resposta ao Item (TRI) que, a princípio, veio completar limitações da Teoria Clássica de Medidas, empregada em larga escala até hoje na medida de traços psicológicos. O ponto principal da TRI é que ela leva em consideração o item particularmente, sem relevar os escores totais; p...

  18. An item factor analysis and item response theory-based revision of the Everyday Discrimination Scale.

    Science.gov (United States)

    Stucky, Brian D; Gottfredson, Nisha C; Panter, A T; Daye, Charles E; Allen, Walter R; Wightman, Linda F

    2011-04-01

    The Everyday Discrimination Scale (EDS), a widely used measure of daily perceived discrimination, is purported to be unidimensional, to function well among African Americans, and to have adequate construct validity. Two separate studies and data sources were used to examine and cross-validate the psychometric properties of the EDS. In Study 1, an exploratory factor analysis was conducted on a sample of African American law students (N = 589), providing strong evidence of local dependence, or nuisance multidimensionality within the EDS. In Study 2, a separate nationally representative community sample (N = 3,527) was used to model the identified local dependence in an item factor analysis (i.e., bifactor model). Next, item response theory (IRT) calibrations were conducted to obtain item parameters. A five-item, revised-EDS was then tested for gender differential item functioning (in an IRT framework). Based on these analyses, a summed score to IRT-scaled score translation table is provided for the revised-EDS. Our results indicate that the revised-EDS is unidimensional, with minimal differential item functioning, and retains predictive validity consistent with the original scale.

  19. Logistics Reduction Technologies for Exploration Missions

    Science.gov (United States)

    Broyan, James L., Jr.; Ewert, Michael K.; Fink, Patrick W.

    2014-01-01

    Human exploration missions under study are limited by the launch mass capacity of existing and planned launch vehicles. The logistical mass of crew items is typically considered separate from the vehicle structure, habitat outfitting, and life support systems. Although mass is typically the focus of exploration missions, due to its strong impact on launch vehicle and habitable volume for the crew, logistics volume also needs to be considered. NASA's Advanced Exploration Systems (AES) Logistics Reduction and Repurposing (LRR) Project is developing six logistics technologies guided by a systems engineering cradle-to-grave approach to enable after-use crew items to augment vehicle systems. Specifically, AES LRR is investigating the direct reduction of clothing mass, the repurposing of logistical packaging, the use of autonomous logistics management technologies, the processing of spent crew items to benefit radiation shielding and water recovery, and the conversion of trash to propulsion gases. Reduction of mass has a corresponding and significant impact to logistical volume. The reduction of logistical volume can reduce the overall pressurized vehicle mass directly, or indirectly benefit the mission by allowing for an increase in habitable volume during the mission. The systematic implementation of these types of technologies will increase launch mass efficiency by enabling items to be used for secondary purposes and improve the habitability of the vehicle as mission durations increase. Early studies have shown that the use of advanced logistics technologies can save approximately 20 m(sup 3) of volume during transit alone for a six-person Mars conjunction class mission.

  20. NBC Contamination Survivability, Large Item Exteriors

    Science.gov (United States)

    2007-11-02

    Perform these tasks (timed) in the standard garment. .(3) Perform these tasks (timed) in mission-oriented protective posture level 4 (MOPP4). (4...bring the chamber to the environmental conditions specified for the test. Condition the test item until it has equilibrated at 30±50 C. Temperature and...condition that all essential operations can be continued in the lowest protective posture consistent with the mission and threat, and without long-term

  1. CTTITEM: SAS macro and SPSS syntax for classical item analysis.

    Science.gov (United States)

    Lei, Pui-Wa; Wu, Qiong

    2007-08-01

    This article describes the functions of a SAS macro and an SPSS syntax that produce common statistics for conventional item analysis including Cronbach's alpha, item difficulty index (p-value or item mean), and item discrimination indices (D-index, point biserial and biserial correlations for dichotomous items and item-total correlation for polytomous items). These programs represent an improvement over the existing SAS and SPSS item analysis routines in terms of completeness and user-friendliness. To promote routine evaluations of item qualities in instrument development of any scale, the programs are available at no charge for interested users. The program codes along with a brief user's manual that contains instructions and examples are downloadable from suen.ed.psu.edu/-pwlei/plei.htm.

  2. Assessing the Psychometric Properties of Alternative Items for Certification.

    Science.gov (United States)

    Krogh, Mary Anne; Muckle, Timothy

    Alternative items were added as scored items to the National Certification Examination for Nurse Anesthetists (NCE) in 2010. A common concern related to the new items has been their measurement attributes. This study was undertaken to evaluate the psychometric impact of adding these items to the examination. Candidates had a significantly higher ability estimate in alternative items than in multiple choice questions and 6.7 percent of test candidates performed significantly differently in alternative item formats. The ability estimates of multiple choice questions correlated at r = .58. The alternative items took significantly longer time to answer than standard multiple choice questions and discriminated to a higher degree than MCQs. The alternative items exhibited unidimensionality to the same degree as MCQs and the BIC confirmed the Rasch model as acceptable for scoring. The new item types were found to have acceptable attributes for inclusion in the certification program.

  3. Dynamic and Comprehensive Item Selection Strategies for Computerized Adaptive Testing Based on Graded Response Model%多级评分计算机化自适应测验动态综合选题策略

    Institute of Scientific and Technical Information of China (English)

    罗芬; 丁树良; 王晓庆

    2012-01-01

    Item selection strategy (ISS) is a core component in Computerized Adaptive Testing (CAT). Polytomous items can provide more information about examinee compared with dichotomous items, and adopting polytomously scored items in test is a research direction of CAT. As we know, the most widely used ISS is the maximum Fisher information (MFI) criterion, which raises concerns about cost-efficiency of the pool utilization and poses security risks for CAT programs. Chang & Ying (1999) and Chang, Qian, & Ying (2001) proposed two alternative item selection procedures, the a-stratified method (a-STR) and the a-stratified with b blocking method (&-STR) based on dichotomous model, with the goal to remedy the problems of item overexposure and item underexposure produced by MFI. However, the technology of a-STR and fc-STR is static because the items are stratified according to the given information at the beginning of test. Based on graded response model (GRM), a technique of the reduction dimensionality of difficulty (or step) parameters was employed[0] to construct some ISSs recently. The limitation of this dimension reduction technique is that it loses a lot of information. Thus, in order to improve MFI, two new item selection methods are proposed based on GRM: (1) modify the technique of the reduction dimensionality of difficulty (or step) parameters by integrating the interval estimation; (2) dynamic a-STR and dynamic fc-STR methods are implemented in the testing process. On one hand, these new ISSs can avoid and remedy the limitations of MFI and make good use of the advantages of the Fisher information function (FIF); FIF compresses all item parameters and ability parameters, so it is a comprehensive tool for all parameters in nature. On the other hand, the new ISSs employ the property that FIF could represent the inverse of the variance of the ability estimation, let £ be the square root of the reciprocal ofthe Fisher information, d be the absolute deviation between the

  4. Maximum Variance Hashing via Column Generation

    Directory of Open Access Journals (Sweden)

    Lei Luo

    2013-01-01

    item search. Recently, a number of data-dependent methods have been developed, reflecting the great potential of learning for hashing. Inspired by the classic nonlinear dimensionality reduction algorithm—maximum variance unfolding, we propose a novel unsupervised hashing method, named maximum variance hashing, in this work. The idea is to maximize the total variance of the hash codes while preserving the local structure of the training data. To solve the derived optimization problem, we propose a column generation algorithm, which directly learns the binary-valued hash functions. We then extend it using anchor graphs to reduce the computational cost. Experiments on large-scale image datasets demonstrate that the proposed method outperforms state-of-the-art hashing methods in many cases.

  5. Lexicon generation methods, lexicon generation devices, and lexicon generation articles of manufacture

    Science.gov (United States)

    Carter, Richard J [Richland, WA; McCall, Jonathon D [West Richland, WA; Whitney, Paul D [Richland, WA; Gregory, Michelle L [Richland, WA; Turner, Alan E [Kennewick, WA; Hetzler, Elizabeth G [Kennewick, WA; White, Amanda M [Kennewick, WA; Posse, Christian [Seattle, WA; Nakamura, Grant C [Kennewick, WA

    2010-10-26

    Lexicon generation methods, computer implemented lexicon editing methods, lexicon generation devices, lexicon editors, and articles of manufacture are described according to some aspects. In one aspect, a lexicon generation method includes providing a seed vector indicative of occurrences of a plurality of seed terms within a plurality of text items, providing a plurality of content vectors indicative of occurrences of respective ones of a plurality of content terms within the text items, comparing individual ones of the content vectors with respect to the seed vector, and responsive to the comparing, selecting at least one of the content terms as a term of a lexicon usable in sentiment analysis of text.

  6. What Do You Think You Are Measuring? A Mixed-Methods Procedure for Assessing the Content Validity of Test Items and Theory-Based Scaling.

    Science.gov (United States)

    Koller, Ingrid; Levenson, Michael R; Glück, Judith

    2017-01-01

    The valid measurement of latent constructs is crucial for psychological research. Here, we present a mixed-methods procedure for improving the precision of construct definitions, determining the content validity of items, evaluating the representativeness of items for the target construct, generating test items, and analyzing items on a theoretical basis. To illustrate the mixed-methods content-scaling-structure (CSS) procedure, we analyze the Adult Self-Transcendence Inventory, a self-report measure of wisdom (ASTI, Levenson et al., 2005). A content-validity analysis of the ASTI items was used as the basis of psychometric analyses using multidimensional item response models (N = 1215). We found that the new procedure produced important suggestions concerning five subdimensions of the ASTI that were not identifiable using exploratory methods. The study shows that the application of the suggested procedure leads to a deeper understanding of latent constructs. It also demonstrates the advantages of theory-based item analysis.

  7. Application of Item Response Theory to Modeling of Expanded Disability Status Scale in Multiple Sclerosis.

    Science.gov (United States)

    Novakovic, A M; Krekels, E H J; Munafo, A; Ueckert, S; Karlsson, M O

    2017-01-01

    In this study, we report the development of the first item response theory (IRT) model within a pharmacometrics framework to characterize the disease progression in multiple sclerosis (MS), as measured by Expanded Disability Status Score (EDSS). Data were collected quarterly from a 96-week phase III clinical study by a blinder rater, involving 104,206 item-level observations from 1319 patients with relapsing-remitting MS (RRMS), treated with placebo or cladribine. Observed scores for each EDSS item were modeled describing the probability of a given score as a function of patients' (unobserved) disability using a logistic model. Longitudinal data from placebo arms were used to describe the disease progression over time, and the model was then extended to cladribine arms to characterize the drug effect. Sensitivity with respect to patient disability was calculated as Fisher information for each EDSS item, which were ranked according to the amount of information they contained. The IRT model was able to describe baseline and longitudinal EDSS data on item and total level. The final model suggested that cladribine treatment significantly slows disease-progression rate, with a 20% decrease in disease-progression rate compared to placebo, irrespective of exposure, and effects an additional exposure-dependent reduction in disability progression. Four out of eight items contained 80% of information for the given range of disabilities. This study has illustrated that IRT modeling is specifically suitable for accurate quantification of disease status and description and prediction of disease progression in phase 3 studies on RRMS, by integrating EDSS item-level data in a meaningful manner.

  8. [Unfolding item response model using best-worst scaling].

    Science.gov (United States)

    Ikehara, Kazuya

    2015-02-01

    In attitude measurement and sensory tests, the unfolding model is typically used. In this model, response probability is formulated by the distance between the person and the stimulus. In this study, we proposed an unfolding item response model using best-worst scaling (BWU model), in which a person chooses the best and worst stimulus among repeatedly presented subsets of stimuli. We also formulated an unfolding model using best scaling (BU model), and compared the accuracy of estimates between the BU and BWU models. A simulation experiment showed that the BWU modell performed much better than the BU model in terms of bias and root mean square errors of estimates. With reference to Usami (2011), the proposed models were apllied to actual data to measure attitudes toward tardiness. Results indicated high similarity between stimuli estimates generated with the proposed models and those of Usami (2011).

  9. CONFIGURATION GENERATOR MODEL

    Energy Technology Data Exchange (ETDEWEB)

    A. Alsaed

    2004-11-18

    ''The Disposal Criticality Analysis Methodology Topical Report'' prescribes an approach to the methodology for performing postclosure criticality analyses within the monitored geologic repository at Yucca Mountain, Nevada. An essential component of the methodology is the ''Configuration Generator Model for In-Package Criticality'' that provides a tool to evaluate the probabilities of degraded configurations achieving a critical state. The configuration generator model is a risk-informed, performance-based process for evaluating the criticality potential of degraded configurations in the monitored geologic repository. The method uses event tree methods to define configuration classes derived from criticality scenarios and to identify configuration class characteristics (parameters, ranges, etc.). The probabilities of achieving the various configuration classes are derived in part from probability density functions for degradation parameters. The NRC has issued ''Safety Evaluation Report for Disposal Criticality Analysis Methodology Topical Report, Revision 0''. That report contained 28 open items that required resolution through additional documentation. Of the 28 open items, numbers 5, 6, 9, 10, 18, and 19 were concerned with a previously proposed software approach to the configuration generator methodology and, in particular, the k{sub eff} regression analysis associated with the methodology. However, the use of a k{sub eff} regression analysis is not part of the current configuration generator methodology and, thus, the referenced open items are no longer considered applicable and will not be further addressed.

  10. Ninth wood energy symposium - Reduction of fine-dust emissions and power generation as part of a future power supply system; 9. Holzenergie-Symposium - Feinstaubminderung und Stromerzeugung im Rahmen der zukuenftigen Energieversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T. (ed.)

    2006-07-01

    This comprehensive report is published by the Swiss Federal Office of Energy (SFOE). A total of fourteen papers were presented at the symposium on the following subjects: Federal Action-Plan in the wood-firing area and emission limits, Fair-Firing - an Action Plan for the prevention of increased emissions and illegal incineration of wastes, fine-dust from wood-fired systems in comparison with diesel soot from the health point of view, practical experience with low-particle, pellets-fired systems, basics and technologies for the precipitation of fine-dust and the influence of particle characteristics and mode of operation as well as two papers on the development of electrical precipitators for wood-fired systems from 200 kW upwards and the practical experience gained with them. Further, papers are presented that deal with small-size electrostatic precipitators, flameless combustion for NO{sub x} reduction and modern pellets technology. The potential and economic viability of wood fuels for the generation of electricity are discussed and a 7 MW{sub e} wood-fired power station is looked at. Finally, the options open for providing a secure supply of energy in Europe are discussed and the role to be played by biomass is examined.

  11. La(0.4)Ba(0.6)Fe(0.8)Zn(0.2)O(3-delta) as cathode in solid oxide fuel cells for simultaneous NO reduction and electricity generation.

    Science.gov (United States)

    Zhou, Renjie; Bu, Yunfei; Xu, Dandan; Zhong, Qin

    2014-01-01

    A perovskite-type oxide La(0.4)Ba(0.6)Fe(0.8)Zn(0.2)O(3-delta) (LBFZ) was investigated as the cathode material for simultaneous NO reduction and electricity generation in solid oxide fuel cells (SOFCs). The microstructure of LBFZ was demonstrated by X-ray diffraction and scanning electron microscopy. The results showed that a single cubic perovskite LBFZ was formed after calcined at 1100 degrees C. Meanwhile, the solid-state reaction between LBFZ and Ce(0.8)Sm(0.2)O(1.9) (SDC) at 900 degrees C was negligible. To measure the electrochemical properties, SOFC units were constructed with Sm(0.9)Sr(0.1)Cr(0.5)Fe(0.5)O3 as the anode, SDC as the electrolyte and LBFZ as the cathode. The maximum power density increased with the increasing NO concentration and temperature. The cell resistance is mainly due to the cathodic polarization resistance.

  12. Pengendalian Persediaan Primary Items dalam Logistik Konstruksi

    Directory of Open Access Journals (Sweden)

    Lady Lisya

    2016-09-01

    Full Text Available Construction logistics are activities that consist of ordering, storage and transportation of materials of construction projects. Storage material is logistics activity that ensure the availability of materials in project site. Generally, material storage activities have been conducted at the project site. Logistics construction is aimed to support the project activities that the completion schedule has been set. Construction logistics issues is determining the schedule of ordering materials so that the project can be implemented on schedule. The purpose of research is to determine the optimum ordering period for the primary items on the main building structure construction and designing inventory control cards as a mechanism for monitoring procurement of materials. This research has been obtained optimal ordering period for the primary items of main building structure with elements of the work using Fixed Period Requirement method. Inventories were already meet the material requirement of each period. Material management has been conducted based grouping approach as many as 31 groups. In addition, this research has proposed the inventory control cards as an instrument for material procurement monitoring. The implications of inventory control cards are coordinate contracting parties with vendors to plan the replenishment  of materials to meet the work schedule. Further research can be developed with other aspects such as integrated material order system between contractors and vendors to consider the safety stock. In addition, the information system for planning material is an important consideration for construction projects with large scale so that the companies can plan primary items inventory and other materials in the projects completion more easily, quickly and accurately.

  13. Calculating impact factor: how bibliographical classification of journal items affects the impact factor of large and small journals.

    Science.gov (United States)

    Golubic, Rajna; Rudes, Mihael; Kovacic, Natasa; Marusic, Matko; Marusic, Ana

    2008-03-01

    As bibliographical classification of published journal items affects the denominator in this equation, we investigated how the numerator and denominator of the impact factor (IF) equation were generated for representative journals in two categories of the Journal Citation Reports (JCR). We performed a full text search of the 1st-ranked journal in 2004 JCR category "Medicine, General and Internal" (New England Journal of Medicine, NEJM, IF = 38.570) and 61st-ranked journal (Croatian Medical Journal, CMJ, IF = 0.690), 1st-ranked journal in category "Multidisciplinary Sciences" (Nature, IF = 32.182) and journal with a relative rank of CMJ (Anais da Academia Brasileira de Ciencias, AABC, IF = 0.435). Large journals published more items categorized by Web of Science (WoS) as non-research items (editorial material, letters, news, book reviews, bibliographical items, or corrections): 63% out of total 5,193 items in Nature and 81% out of 3,540 items in NEJM, compared with 31% out of 283 items in CMJ and only 2 (2%) out of 126 items in AABC. Some items classified by WoS as non-original contained original research data (9.5% in Nature, 7.2% in NEJM, 13.7% in CMJ and none in AABC). These items received a significant number of citations: 6.9% of total citations in Nature, 14.7% in NEJM and 18.5% in CMJ. IF decreased for all journals when only items presenting original research and citations to them were used for IF calculation. Regardless of the journal's size or discipline, publication of non-original research and its classification by the bibliographical database have an effect on both numerator and denominator of the IF equation.

  14. Small-Item Contact Test Method, FY11 Release

    Science.gov (United States)

    2012-07-01

    sections on an item. Often designated in a sampling plan and marked on an item to enable quick reference. • sessile drop : A liquid droplet that is...Full item contamination illustration 25 9. Localized contamination illustration 25 10. Gross sample collection technique for small items 32 Blank...decontaminant performance. contamination set: A specific contamination density, drop volume, and deposition pattern combination used for dose confirmation

  15. Negative affect impairs associative memory but not item memory.

    OpenAIRE

    Bisby, J. A.; Burgess, N.

    2014-01-01

    The formation of associations between items and their context has been proposed to rely on mechanisms distinct from those supporting memory for a single item. Although emotional experiences can profoundly affect memory, our understanding of how it interacts with different aspects of memory remains unclear. We performed three experiments to examine the effects of emotion on memory for items and their associations. By presenting neutral and negative items with background contexts, Experiment 1 ...

  16. The frequency of item writing flaws in multiple-choice questions used in high stakes nursing assessments.

    Science.gov (United States)

    Tarrant, Marie; Knierim, Aimee; Hayes, Sasha K; Ware, James

    2006-12-01

    Multiple-choice questions are a common assessment method in nursing examinations. Few nurse educators, however, have formal preparation in constructing multiple-choice questions. Consequently, questions used in baccalaureate nursing assessments often contain item-writing flaws, or violations to accepted item-writing guidelines. In one nursing department, 2770 MCQs were collected from tests and examinations administered over a five-year period from 2001 to 2005. Questions were evaluated for 19 frequently occurring item-writing flaws, for cognitive level, for question source, and for the distribution of correct answers. Results show that almost half (46.2%) of the questions contained violations of item-writing guidelines and over 90% were written at low cognitive levels. Only a small proportion of questions were teacher generated (14.1%), while 36.2% were taken from testbanks and almost half (49.4%) had no source identified. MCQs written at a lower cognitive level were significantly more likely to contain item-writing flaws. While there was no relationship between the source of the question and item-writing flaws, teacher-generated questions were more likely to be written at higher cognitive levels (pwriting is recommended for all faculty members who are responsible for developing tests. Pre-test review and quality assessment is also recommended to reduce the occurrence of item-writing flaws and to improve the quality of test questions.

  17. Curriculum, Translation, and Differential Functioning of Measurement and Geometry Items

    Science.gov (United States)

    Emenogu, Barnabas C.; Childs, Ruth A.

    2005-01-01

    A test item exhibits differential item functioning (DIF) if students with the same ability find it differentially difficult. When the item is administered in French and English, differences in language difficulty and meaning are the most likely explanations. However, curriculum differences may also contribute to DIF. The responses of Ontario…

  18. 41 CFR 101-27.209-1 - GSA stock items.

    Science.gov (United States)

    2010-07-01

    ...-Management of Shelf-Life Materials § 101-27.209-1 GSA stock items. Shelf-life items that meet the criteria... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true GSA stock items. 101-27.209-1 Section 101-27.209-1 Public Contracts and Property Management Federal Property Management...

  19. The Identification of Radex Properties in Objective Test Items.

    Science.gov (United States)

    Seddon, G. M.; And Others

    1981-01-01

    In a Monte Carlo simulation, a methodology was developed to investigate the existence of radex properties among objective test items. In an experiment with items covering four categories of Bloom's cognitive domain taxonomy, the items did not have the factorial properties of a radex with four levels of complexity. (Author/BW)

  20. Effect of Multiple Testing Adjustment in Differential Item Functioning Detection

    Science.gov (United States)

    Kim, Jihye; Oshima, T. C.

    2013-01-01

    In a typical differential item functioning (DIF) analysis, a significance test is conducted for each item. As a test consists of multiple items, such multiple testing may increase the possibility of making a Type I error at least once. The goal of this study was to investigate how to control a Type I error rate and power using adjustment…

  1. Multistage Computerized Adaptive Testing with Uniform Item Exposure

    Science.gov (United States)

    Edwards, Michael C.; Flora, David B.; Thissen, David

    2012-01-01

    This article describes a computerized adaptive test (CAT) based on the uniform item exposure multi-form structure (uMFS). The uMFS is a specialization of the multi-form structure (MFS) idea described by Armstrong, Jones, Berliner, and Pashley (1998). In an MFS CAT, the examinee first responds to a small fixed block of items. The items comprising…

  2. Stochastic Approximation Methods for Latent Regression Item Response Models

    Science.gov (United States)

    von Davier, Matthias; Sinharay, Sandip

    2010-01-01

    This article presents an application of a stochastic approximation expectation maximization (EM) algorithm using a Metropolis-Hastings (MH) sampler to estimate the parameters of an item response latent regression model. Latent regression item response models are extensions of item response theory (IRT) to a latent variable model with covariates…

  3. A method for designing IRT-based item banks

    NARCIS (Netherlands)

    Boekkooi-Timminga, Ellen

    1990-01-01

    Since 1985 several procedures for computerized test construction using linear programing techniques have been described in the literature. To apply these procedures successfully, suitable item banks are needed. The problem of designing item banks based on item response theory (IRT) is addressed. A p

  4. Higher-Order Item Response Models for Hierarchical Latent Traits

    Science.gov (United States)

    Huang, Hung-Yu; Wang, Wen-Chung; Chen, Po-Hsi; Su, Chi-Ming

    2013-01-01

    Many latent traits in the human sciences have a hierarchical structure. This study aimed to develop a new class of higher order item response theory models for hierarchical latent traits that are flexible in accommodating both dichotomous and polytomous items, to estimate both item and person parameters jointly, to allow users to specify…

  5. The Applicability of Interactive Item Templates in Varied Knowledge Types

    Science.gov (United States)

    Koong, Chorng-Shiuh; Wu, Chi-Ying

    2011-01-01

    A well-edited assessment can enhance student's learning motives. Applicability of items, which includes item content and template, plays a crucial role in authoring a good assessment. Templates in discussion contain not only conventional true & false, multiple choice, completion item and short answer but also of those interactive ones. Methods…

  6. DIF Trees: Using Classification Trees to Detect Differential Item Functioning

    Science.gov (United States)

    Vaughn, Brandon K.; Wang, Qiu

    2010-01-01

    A nonparametric tree classification procedure is used to detect differential item functioning for items that are dichotomously scored. Classification trees are shown to be an alternative procedure to detect differential item functioning other than the use of traditional Mantel-Haenszel and logistic regression analysis. A nonparametric…

  7. Guide to good practices for the development of test items

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    While the methodology used in developing test items can vary significantly, to ensure quality examinations, test items should be developed systematically. Test design and development is discussed in the DOE Guide to Good Practices for Design, Development, and Implementation of Examinations. This guide is intended to be a supplement by providing more detailed guidance on the development of specific test items. This guide addresses the development of written examination test items primarily. However, many of the concepts also apply to oral examinations, both in the classroom and on the job. This guide is intended to be used as guidance for the classroom and laboratory instructor or curriculum developer responsible for the construction of individual test items. This document focuses on written test items, but includes information relative to open-reference (open book) examination test items, as well. These test items have been categorized as short-answer, multiple-choice, or essay. Each test item format is described, examples are provided, and a procedure for development is included. The appendices provide examples for writing test items, a test item development form, and examples of various test item formats.

  8. Is the New Item Priority Effect an Experimental Artifact?

    Science.gov (United States)

    Andre, Thomas

    This research was directed at determining whether the new item priority (NIP) effect in free recall was a result of an experimental artifact produced by the joint action of the serial position effect and the randomization of items over trials, or a consequence of a strategy of recalling newer items before older ones. In the experiment, subjects…

  9. The Feasibility of Single-Item Measures for Organizational Justice

    Science.gov (United States)

    Jordan, Jeremy S.; Turner, Brian A.

    2008-01-01

    Researchers in a number of disciplines have examined the utility of single-item measures for both affective and cognitive constructs. While these authors have indicated that, under certain circumstances, the use of single-item measures is appropriate, there remains concern regarding the reliability and validity of single-item measures. This study…

  10. The Applicability of Interactive Item Templates in Varied Knowledge Types

    Science.gov (United States)

    Koong, Chorng-Shiuh; Wu, Chi-Ying

    2011-01-01

    A well-edited assessment can enhance student's learning motives. Applicability of items, which includes item content and template, plays a crucial role in authoring a good assessment. Templates in discussion contain not only conventional true & false, multiple choice, completion item and short answer but also of those interactive ones. Methods…

  11. Gating Items: Definition, Significance, and Need for Further Study

    Science.gov (United States)

    Judd, Wallace

    2009-01-01

    Over the past twenty years in performance testing a specific item type with distinguishing characteristics has arisen time and time again. It's been invented independently by dozens of test development teams. And yet this item type is not recognized in the research literature. This article is an invitation to investigate the item type, evaluate…

  12. The Development of Practical Item Analysis Program for Indonesian Teachers

    Science.gov (United States)

    Muhson, Ali; Lestari, Barkah; Supriyanto; Baroroh, Kiromim

    2017-01-01

    Item analysis has essential roles in the learning assessment. The item analysis program is designed to measure student achievement and instructional effectiveness. This study was aimed to develop item-analysis program and verify its feasibility. This study uses a Research and Development (R & D) model. The procedure includes designing and…

  13. A Procedure for Linear Polychotomous Scoring of Test Items

    Science.gov (United States)

    1993-10-01

    associated with the response categories of test items . When tests are scored using these scoring weights, test reliability increases. The new procedure is...program POLY. The example demonstrates how polyweighting can be used to calibrate and score test items drawn from an item bank that is too large to

  14. Primary Science Assessment Item Setters' Misconceptions Concerning Biological Science Concepts

    Science.gov (United States)

    Boo, Hong Kwen

    2007-01-01

    Assessment is an integral and vital part of teaching and learning, providing feedback on progress through the assessment period to both learners and teachers. However, if test items are flawed because of misconceptions held by the question setter, then such test items are invalid as assessment tools. Moreover, such flawed items are also likely to…

  15. Classroom Test Writing: Effects of Item Format on Test Quality.

    Science.gov (United States)

    Torabi-Parizi, Rosa; Campbell, Noma Jo

    1982-01-01

    Investigates the effects of varying the placement of blanks and the number of options available in multiple-choice items on the reliability of fifth-grade students' scores. Results indicate that scores on three-choice item tests were not less reliable than scores on four-choice item tests. A similar finding was found regarding the placement of…

  16. Influence of Item Direction on Student Responses in Attitude Assessment.

    Science.gov (United States)

    Campbell, Noma Jo; Grissom, Stephen

    To investigate the effects of wording in attitude test items, a five-point Likert-type rating scale was administered to 173 undergraduate education majors. The test measured attitudes toward college and self, and contained 38 positively-worded items. Thirty-eight negatively-worded items were also written to parallel the positive statements.…

  17. Analysis of Differential Item Functioning in the NAEP History Assessment.

    Science.gov (United States)

    Zwick, Rebecca; Ercikan, Kadriye

    The Mantel-Haenszel approach for investigating differential item functioning (DIF) was applied to U.S. history items that were administered as part of the National Assessment of Educational Progress (NAEP). DIF analyses were based on the responses of 7,743 students in grade 11. On some items, Blacks, Hispanics, and females performed more poorly…

  18. 41 CFR 101-28.306-6 - Sensitive items.

    Science.gov (United States)

    2010-07-01

    ... for embarrassment of GSA and customer agencies, the level of customer complaints, and control as an accountable item of personal property. Each customer activity shall take all appropriate measures necessary to... 28.3-Customer Supply Centers § 101-28.306-6 Sensitive items. Many items stocked by the CSCs may...

  19. Social Desirability Scale Values of Locus of Control Items

    Science.gov (United States)

    Kestenbaum, Joel M.

    1976-01-01

    Subjects rated each item in Rotter's I-E Scale for its social desirability value. Social desirability scale values (SDSV) of paired items were compared with one another. Results indicate that paired items are not similar in their SDSV, thus enabling subjects to respond on the basis of social desirability. (Author/DEP)

  20. 17 CFR 229.1100 - (Item 1100) General.

    Science.gov (United States)

    2010-04-01

    ... AND CONSERVATION ACT OF 1975-REGULATION S-K Asset-Backed Securities (Regulation AB) § 229.1100 (Item... source of various disclosure items and requirements for “asset-backed securities” filings under the... this Regulation AB, including the definition of “asset-backed security,” are set forth in Item 1101. (b...

  1. Item validity of the Myers-Briggs Type Indicator.

    Science.gov (United States)

    Tzeng, O C; Outcalt, D; Boyer, S L; Ware, R; Landis, D

    1984-06-01

    The present study presents a brief summary of four extensive psychometric analyses of the Myers-Briggs Type Indicator (MBTI) items. Positive empirical evidence supports the MBTI item validity. However, several measurement issues on item construction were raised to caution the future users.

  2. Revision of cost items in the account classification of the company

    OpenAIRE

    Smejkalová, Kateřina

    2012-01-01

    The subject of the bachelor thesis "Revision of cost items in the account classification of the company" is primarily analytical accounts reduction of overheads in particular company. In addition to editing the account classification there are defined accounting contents analytical overheads. To accomplish the above there helps detailed analysis of problematic analytical accounts. The bachelor thesis also entitles a chapter about functioning of the costs accounting, including its function and...

  3. Differential PIXE analysis of Mesoamerican jewelry items

    Science.gov (United States)

    Demortier, G.; Ruvalcaba-Sil, J. L.

    1996-09-01

    Gold jewelry items of Mesoamerican origin (from Peru, Colombia, Mexico, etc,…) are usually cast in Tumbaga: a man-made gold-copper-silver alloy containing a large proportion of copper. In order to give the objects a colour close to that of pure gold, ancient Mesoamerican goldsmiths experimented with a procedure to eliminate less noble metals (like copper and silver) from the surface. RBS may be used to identify a possible enrichment in gold in the most external layer of the items but due to the low capability of this technique to separate scattered particles on gold and silver and due to the low Rutherford cross section for α-particles on copper by comparison with those on gold, the determination of the exact depth depletion of copper cannot be easily reached. Differential PIXE is an appropriate method to achieve this goal. It takes the relative X-ray intensities of Cu and Au lines into account. By varying the incident proton energy, this ratio is modified in a completely different way if the sample is homogeneous or exhibits a layered or depth profile structure.

  4. The Generation Effect and Memory

    OpenAIRE

    Rosner, Zachary Alexander

    2012-01-01

    Educators and psychologists have extolled the benefits of active learning techniques such as organizing material, self-explaining, learning through experience, and practicing retrieval for years. Underlying these strategies is the generation effect, an encoding phenomenon in which actively generating rather than passively learning information improves the subsequent retrieval of item information. Despite rather extensive analysis of the generation effect, the processes underlying it are not f...

  5. Feasible Dose Reduction in Routine Chest Computed Tomography Maintaining Constant Image Quality Using the Last Three Scanner Generations: From Filtered Back Projection to Sinogram-affirmed Iterative Reconstruction and Impact of the Novel Fully Integrated Detector Design Minimizing Electronic Noise

    Directory of Open Access Journals (Sweden)

    Lukas Ebner

    2014-01-01

    Full Text Available Objective:The aim of the present study was to evaluate a dose reduction in contrast-enhanced chest computed tomography (CT by comparing the three latest generations of Siemens CT scanners used in clinical practice. We analyzed the amount of radiation used with filtered back projection (FBP and an iterative reconstruction (IR algorithm to yield the same image quality. Furthermore, the influence on the radiation dose of the most recent integrated circuit detector (ICD; Stellar detector, Siemens Healthcare, Erlangen, Germany was investigated. Materials and Methods: 136 Patients were included. Scan parameters were set to a thorax routine: SOMATOM Sensation 64 (FBP, SOMATOM Definition Flash (IR, and SOMATOM Definition Edge (ICD and IR. Tube current was set constantly to the reference level of 100 mA automated tube current modulation using reference milliamperes. Care kV was used on the Flash and Edge scanner, while tube potential was individually selected between 100 and 140 kVp by the medical technologists at the SOMATOM Sensation. Quality assessment was performed on soft-tissue kernel reconstruction. Dose was represented by the dose length product. Results: Dose-length product (DLP with FBP for the average chest CT was 308 mGycm ± 99.6. In contrast, the DLP for the chest CT with IR algorithm was 196.8 mGycm ± 68.8 (P = 0.0001. Further decline in dose can be noted with IR and the ICD: DLP: 166.4 mGycm ± 54.5 (P = 0.033. The dose reduction compared to FBP was 36.1% with IR and 45.6% with IR/ICD. Signal-to-noise ratio (SNR was favorable in the aorta, bone, and soft tissue for IR/ICD in combination compared to FBP (the P values ranged from 0.003 to 0.048. Overall contrast-to-noise ratio (CNR improved with declining DLP. Conclusion: The most recent technical developments, namely IR in combination with integrated circuit detectors, can significantly lower radiation dose in chest CT examinations.

  6. The Academic Medical Center Linear Disability Score (ALDS) item bank: item response theory analysis in a mixed patient population.

    Science.gov (United States)

    Holman, Rebecca; Weisscher, Nadine; Glas, Cees A W; Dijkgraaf, Marcel G W; Vermeulen, Marinus; de Haan, Rob J; Lindeboom, Robert

    2005-12-29

    Currently, there is a lot of interest in the flexible framework offered by item banks for measuring patient relevant outcomes. However, there are few item banks, which have been developed to quantify functional status, as expressed by the ability to perform activities of daily life. This paper examines the measurement properties of the Academic Medical Center linear disability score item bank in a mixed population. This paper uses item response theory to analyse data on 115 of 170 items from a total of 1002 respondents. These were: 551 (55%) residents of supported housing, residential care or nursing homes; 235 (23%) patients with chronic pain; 127 (13%) inpatients on a neurology ward following a stroke; and 89 (9%) patients suffering from Parkinson's disease. Of the 170 items, 115 were judged to be clinically relevant. Of these 115 items, 77 were retained in the item bank following the item response theory analysis. Of the 38 items that were excluded from the item bank, 24 had either been presented to fewer than 200 respondents or had fewer than 10% or more than 90% of responses in the category 'can carry out'. A further 11 items had different measurement properties for younger and older or for male and female respondents. Finally, 3 items were excluded because the item response theory model did not fit the data. The Academic Medical Center linear disability score item bank has promising measurement characteristics for the mixed patient population described in this paper. Further studies will be needed to examine the measurement properties of the item bank in other populations.

  7. The Academic Medical Center Linear Disability Score (ALDS) item bank: item response theory analysis in a mixed patient population

    Science.gov (United States)

    Holman, Rebecca; Weisscher, Nadine; Glas, Cees AW; Dijkgraaf, Marcel GW; Vermeulen, Marinus; de Haan, Rob J; Lindeboom, Robert

    2005-01-01

    Background Currently, there is a lot of interest in the flexible framework offered by item banks for measuring patient relevant outcomes. However, there are few item banks, which have been developed to quantify functional status, as expressed by the ability to perform activities of daily life. This paper examines the measurement properties of the Academic Medical Center linear disability score item bank in a mixed population. Methods This paper uses item response theory to analyse data on 115 of 170 items from a total of 1002 respondents. These were: 551 (55%) residents of supported housing, residential care or nursing homes; 235 (23%) patients with chronic pain; 127 (13%) inpatients on a neurology ward following a stroke; and 89 (9%) patients suffering from Parkinson's disease. Results Of the 170 items, 115 were judged to be clinically relevant. Of these 115 items, 77 were retained in the item bank following the item response theory analysis. Of the 38 items that were excluded from the item bank, 24 had either been presented to fewer than 200 respondents or had fewer than 10% or more than 90% of responses in the category 'can carry out'. A further 11 items had different measurement properties for younger and older or for male and female respondents. Finally, 3 items were excluded because the item response theory model did not fit the data. Conclusion The Academic Medical Center linear disability score item bank has promising measurement characteristics for the mixed patient population described in this paper. Further studies will be needed to examine the measurement properties of the item bank in other populations. PMID:16381611

  8. The Academic Medical Center Linear Disability Score (ALDS item bank: item response theory analysis in a mixed patient population

    Directory of Open Access Journals (Sweden)

    Vermeulen Marinus

    2005-12-01

    Full Text Available Abstract Background Currently, there is a lot of interest in the flexible framework offered by item banks for measuring patient relevant outcomes. However, there are few item banks, which have been developed to quantify functional status, as expressed by the ability to perform activities of daily life. This paper examines the measurement properties of the Academic Medical Center linear disability score item bank in a mixed population. Methods This paper uses item response theory to analyse data on 115 of 170 items from a total of 1002 respondents. These were: 551 (55% residents of supported housing, residential care or nursing homes; 235 (23% patients with chronic pain; 127 (13% inpatients on a neurology ward following a stroke; and 89 (9% patients suffering from Parkinson's disease. Results Of the 170 items, 115 were judged to be clinically relevant. Of these 115 items, 77 were retained in the item bank following the item response theory analysis. Of the 38 items that were excluded from the item bank, 24 had either been presented to fewer than 200 respondents or had fewer than 10% or more than 90% of responses in the category 'can carry out'. A further 11 items had different measurement properties for younger and older or for male and female respondents. Finally, 3 items were excluded because the item response theory model did not fit the data. Conclusion The Academic Medical Center linear disability score item bank has promising measurement characteristics for the mixed patient population described in this paper. Further studies will be needed to examine the measurement properties of the item bank in other populations.

  9. The 12-item World Health Organization Disability Assessment Schedule II (WHO-DAS II: a nonparametric item response analysis

    Directory of Open Access Journals (Sweden)

    Fernandez Ana

    2010-05-01

    Full Text Available Abstract Background Previous studies have analyzed the psychometric properties of the World Health Organization Disability Assessment Schedule II (WHO-DAS II using classical omnibus measures of scale quality. These analyses are sample dependent and do not model item responses as a function of the underlying trait level. The main objective of this study was to examine the effectiveness of the WHO-DAS II items and their options in discriminating between changes in the underlying disability level by means of item response analyses. We also explored differential item functioning (DIF in men and women. Methods The participants were 3615 adult general practice patients from 17 regions of Spain, with a first diagnosed major depressive episode. The 12-item WHO-DAS II was administered by the general practitioners during the consultation. We used a non-parametric item response method (Kernel-Smoothing implemented with the TestGraf software to examine the effectiveness of each item (item characteristic curves and their options (option characteristic curves in discriminating between changes in the underliying disability level. We examined composite DIF to know whether women had a higher probability than men of endorsing each item. Results Item response analyses indicated that the twelve items forming the WHO-DAS II perform very well. All items were determined to provide good discrimination across varying standardized levels of the trait. The items also had option characteristic curves that showed good discrimination, given that each increasing option became more likely than the previous as a function of increasing trait level. No gender-related DIF was found on any of the items. Conclusions All WHO-DAS II items were very good at assessing overall disability. Our results supported the appropriateness of the weights assigned to response option categories and showed an absence of gender differences in item functioning.

  10. Association Rule Mining for Both Frequent and Infrequent Items Using Particle Swarm Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    MIR MD. JAHANGIR KABIR

    2014-07-01

    Full Text Available In data mining research, generating frequent items from large databases is one of the important issues and the key factor for implementing association rule mining tasks. Mining infrequent items such as relationships among rare but expensive products is another demanding issue which have been shown in some recent studies. Therefore this study considers user assigned threshold values as a constraint which helps users mine those rules which are more interesting for them. In addition, in real world users may prefer to know relationships among frequent items along with infrequent ones. The particle swarm optimization algorithm is an important heuristic technique in recent years and this study uses this technique to mine association rules effectively. If this technique considers user defined threshold values, interesting association rules can be generated more efficiently. Therefore this study proposes a novel approach which includes using particle swarm optimization algorithm to mine association rules from databases. Our implementation of the search strategy includes bitmap representation of nodes in a lexicographic tree and from superset-subset relationship of the nodes it classifies frequent items along with infrequent itemsets. In addition, this approach avoids extra calculation overhead for generating frequent pattern trees and handling large memory which store the support values of candidate item sets. Our experimental results show that this approach efficiently mines association rules. It accesses a database to calculate a support value for fewer numbers of nodes to find frequent itemsets and from that it generates association rules, which dramatically reduces search time. The main aim of this proposed algorithm is to show how heuristic method works on real databases to find all the interesting association rules in an efficient way.

  11. Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and perfluorinated alkylated substances (PFASs) in traditional seafood items from western Greenland.

    Science.gov (United States)

    Carlsson, Pernilla; Herzke, Dorte; Kallenborn, Roland

    2014-03-01

    In this study, contamination levels were determined for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and perfluorinated alkylated substances (PFASs) in traditional Greenland seafood items, such as raw and smoked fish fillet (salmon and halibut), whale and seal meat and narwhal mattak (skin and blubber). The daily intake of PCBs, PBDEs and PFASs through traditional seafood items in Greenland was assessed. Based on the presented levels of contaminants, in combination with earlier food intake studies, suggests that the daily exposure was below the tolerable daily intake threshold for all compounds. BDE-47 was the only PBDE-congener detected in all food items, except in smoked halibut. The levels of BDE-47 varied from food items such as intestines and blubber have a strong positive effect for the reduction of POPs levels in food, without a reducing the health benefits of traditional food intake considerably.

  12. An integrated single-vendor single-buyer production-inventory model for items with imperfect quality and inspection errors

    Directory of Open Access Journals (Sweden)

    L.F. Hsu

    2012-10-01

    Full Text Available In this paper, we develop an integrated vendor-buyer production-inventory model for items with imperfect quality and inspection errors. The production process is imperfect and produces a certain number of defective items with a known probability density function. We consider the policy in which the delivery quantity to the buyer is identical at each shipment. Once the buyer receives the lot, a 100% screening process of the lot is conducted, and the screening process and demand proceed simultaneously. The screening process is not perfect. The inspector may incorrectly classify a non-defective item as defective, or incorrectly classify a defective item as non-defective. The expected integrated total annual cost of the vendor and the buyer is derived and a solution procedure is provided to find the optimal solution. Numerical examples show that the integrated model gives an impressive cost reduction in comparison to an independent decision by the buyer.

  13. Confirmatory Factor Analysis of the M5-50: An Implementation of the International Personality Item Pool Item Set

    Science.gov (United States)

    Socha, Alan; Cooper, Christopher A.; McCord, David M.

    2010-01-01

    Goldberg's International Personality Item Pool (IPIP; Goldberg, 1999) provides researchers with public-domain, free-access personality measurement scales that are proxies of well-established published scales. One of the more commonly used IPIP sets employs 50 items to measure the 5 broad domains of the 5-factor model, with 10 items per factor. The…

  14. Multidimensional CAT Item Selection Methods for Domain Scores and Composite Scores with Item Exposure Control and Content Constraints

    Science.gov (United States)

    Yao, Lihua

    2014-01-01

    The intent of this research was to find an item selection procedure in the multidimensional computer adaptive testing (CAT) framework that yielded higher precision for both the domain and composite abilities, had a higher usage of the item pool, and controlled the exposure rate. Five multidimensional CAT item selection procedures (minimum angle;…

  15. Multidimensional CAT Item Selection Methods for Domain Scores and Composite Scores with Item Exposure Control and Content Constraints

    Science.gov (United States)

    Yao, Lihua

    2014-01-01

    The intent of this research was to find an item selection procedure in the multidimensional computer adaptive testing (CAT) framework that yielded higher precision for both the domain and composite abilities, had a higher usage of the item pool, and controlled the exposure rate. Five multidimensional CAT item selection procedures (minimum angle;…

  16. Do Images Influence Assessment in Anatomy? Exploring the Effect of Images on Item Difficulty and Item Discrimination

    Science.gov (United States)

    Vorstenbosch, Marc A. T. M.; Klaassen, Tim P. F. M.; Kooloos, Jan G. M.; Bolhuis, Sanneke M.; Laan, Roland F. J. M.

    2013-01-01

    Anatomists often use images in assessments and examinations. This study aims to investigate the influence of different types of images on item difficulty and item discrimination in written assessments. A total of 210 of 460 students volunteered for an extra assessment in a gross anatomy course. This assessment contained 39 test items grouped in…

  17. Peeking into personality test answers: inter- and intraindividual variety in item interpretations.

    Science.gov (United States)

    Arro, Grete

    2013-03-01

    Personality research of today applies basically inventories having neither unambiguously interpretable items nor responses. The substantive process of generating the test answer is rarely investigated and thus the possible field of meanings, out of which the answer is created, remains hidden. In order to investigate the possible array of spontaneous answers to personality test items, a situative open-ended personality inventory was developed to determine individuals' ways of interpreting personality test items and relevant personality descriptions for individuals. The children's sample (N = 704 of 10-13 year olds) answered five free-response contextualized personality test questions, each related to one of the Five Factor Model personality dimensions. It was revealed that there is no universal interpretation of an item. First, different children's answers to same question described different personality dimensions - substantial number of the respondents' answers did not reflect the personality domain assumed in an item. So there are several ways to interpret test questions; answers may refer to different personality dimensions and not necessarily the one assumed by the researcher. Second, a number of children mentioned more than one personality trait for one item, indicating that even within one person there may be several relevant interpretations of the same item. Considering personality traits as occurring one by one and mutually exclusively during personality test answering may be artificial; in reality trait combinations may reflect actual reaction. In sum, the results suggest there is no single predictable interpretational trajectory in meaning construction process if semiotically mediated constructs, e.g., personality reflection, are assessed.

  18. Line-item veto may pass this month

    Science.gov (United States)

    U.S. House and Senate Republicans have cleared the way for legislation to give the President the power of a line-item-veto in time for the 1998 budget season.The line-item veto, as proposed, would allow the President to remove from appropriations bills selected appropriations items, new entitlement spending, or narrowly targeted tax breaks. Once a line item is cut from the budget, Congress would have to pass a separate appropriations bill for that individual item; that new, separate bill would then be subject to the traditional Presidential veto.

  19. A generalized item response tree model for psychological assessments.

    Science.gov (United States)

    Jeon, Minjeong; De Boeck, Paul

    2016-09-01

    A new item response theory (IRT) model with a tree structure has been introduced for modeling item response processes with a tree structure. In this paper, we present a generalized item response tree model with a flexible parametric form, dimensionality, and choice of covariates. The utilities of the model are demonstrated with two applications in psychological assessments for investigating Likert scale item responses and for modeling omitted item responses. The proposed model is estimated with the freely available R package flirt (Jeon et al., 2014b).

  20. The Development of Practical Item Analysis Program for Indonesian Teachers

    Directory of Open Access Journals (Sweden)

    Ali Muhson

    2017-04-01

    Full Text Available Item analysis has essential roles in the learning assessment. The item analysis program is designed to measure student achievement and instructional effectiveness. This study was aimed to develop item-analysis program and verify its feasibility. This study uses a Research and Development (R & D model. The procedure includes designing and developing a product, validating, and testing the product. The data were collected through documentations, questionnaires, and interviews. This study successfully developed item analysis program, namely AnBuso. It is developed based on classical test theory (CTT. It was practical and applicable for Indonesian teachers to analyse test items

  1. Item Discrimination and Type I Error in the Detection of Differential Item Functioning

    Science.gov (United States)

    Li, Yanju; Brooks, Gordon P.; Johanson, George A.

    2012-01-01

    In 2009, DeMars stated that when impact exists there will be Type I error inflation, especially with larger sample sizes and larger discrimination parameters for items. One purpose of this study is to present the patterns of Type I error rates using Mantel-Haenszel (MH) and logistic regression (LR) procedures when the mean ability between the…

  2. Item Analysis and Differential Item Functioning of a Brief Conduct Problem Screen

    Science.gov (United States)

    Wu, Johnny; King, Kevin M.; Witkiewitz, Katie; Racz, Sarah Jensen; McMahon, Robert J.

    2012-01-01

    Research has shown that boys display higher levels of childhood conduct problems than girls, and Black children display higher levels than White children, but few studies have tested for scalar equivalence of conduct problems across gender and race. The authors conducted a 2-parameter item response theory (IRT) model to examine item…

  3. An NCME Instructional Module on Item-Fit Statistics for Item Response Theory Models

    Science.gov (United States)

    Ames, Allison J.; Penfield, Randall D.

    2015-01-01

    Drawing valid inferences from item response theory (IRT) models is contingent upon a good fit of the data to the model. Violations of model-data fit have numerous consequences, limiting the usefulness and applicability of the model. This instructional module provides an overview of methods used for evaluating the fit of IRT models. Upon completing…

  4. Detecting measurement disturbance effects: the graphical display of item characteristics.

    Science.gov (United States)

    Schumacker, Randall E

    2015-01-01

    Traditional identification of misfitting items in Rasch measurement models have interpreted the Infit and Outfit z standardized statistic. A more recent approach made possible by Winsteps is to specify "group = 0" in the control file and subsequently view the item characteristic curve for each item against the true probability curve. The graphical display reveals whether an item follows the true probability curve or deviates substantially, thus indicating measurement disturbance. Probability of item response and logit ability are easily copied into data vectors in R software then graphed. An example control file, output item data, and subsequent preparation of an overlay graph for misfit items are presented using Winsteps and R software. For comparison purposes the data are also analyzed using a multi-dimensional (MD) mapping procedure.

  5. Feed mechanism and method for feeding minute items

    Science.gov (United States)

    Stringer, Timothy Kent; Yerganian, Simon Scott

    2012-11-06

    A feeding mechanism and method for feeding minute items, such as capacitors, resistors, or solder preforms. The mechanism is adapted to receive a plurality of the randomly-positioned and randomly-oriented extremely small or minute items, and to isolate, orient, and position the items in a specific repeatable pickup location wherefrom they may be removed for use by, for example, a computer-controlled automated assembly machine. The mechanism comprises a sliding shelf adapted to receive and support the items; a wiper arm adapted to achieve a single even layer of the items; and a pushing arm adapted to push the items into the pickup location. The mechanism can be adapted for providing the items with a more exact orientation, and can also be adapted for use in a liquid environment.

  6. Item Response Theory Using Hierarchical Generalized Linear Models

    Directory of Open Access Journals (Sweden)

    Hamdollah Ravand

    2015-03-01

    Full Text Available Multilevel models (MLMs are flexible in that they can be employed to obtain item and person parameters, test for differential item functioning (DIF and capture both local item and person dependence. Papers on the MLM analysis of item response data have focused mostly on theoretical issues where applications have been add-ons to simulation studies with a methodological focus. Although the methodological direction was necessary as a first step to show how MLMs can be utilized and extended to model item response data, the emphasis needs to be shifted towards providing evidence on how applications of MLMs in educational testing can provide the benefits that have been promised. The present study uses foreign language reading comprehension data to illustrate application of hierarchical generalized models to estimate person and item parameters, differential item functioning (DIF, and local person dependence in a three-level model.

  7. Identifying Unbiased Items for Screening Preschoolers for Disruptive Behavior Problems.

    Science.gov (United States)

    Studts, Christina R; Polaha, Jodi; van Zyl, Michiel A

    2016-10-25

    OBJECTIVE : Efficient identification and referral to behavioral services are crucial in addressing early-onset disruptive behavior problems. Existing screening instruments for preschoolers are not ideal for pediatric primary care settings serving diverse populations. Eighteen candidate items for a new brief screening instrument were examined to identify those exhibiting measurement bias (i.e., differential item functioning, DIF) by child characteristics. METHOD : Parents/guardians of preschool-aged children (N = 900) from four primary care settings completed two full-length behavioral rating scales. Items measuring disruptive behavior problems were tested for DIF by child race, sex, and socioeconomic status using two approaches: item response theory-based likelihood ratio tests and ordinal logistic regression. RESULTS : Of 18 items, eight were identified with statistically significant DIF by at least one method. CONCLUSIONS : The bias observed in 8 of 18 items made them undesirable for screening diverse populations of children. These items were excluded from the new brief screening tool.

  8. The effects of relative food item size on optimal tooth cusp sharpness during brittle food item processing.

    Science.gov (United States)

    Berthaume, Michael A; Dumont, Elizabeth R; Godfrey, Laurie R; Grosse, Ian R

    2014-12-01

    Teeth are often assumed to be optimal for their function, which allows researchers to derive dietary signatures from tooth shape. Most tooth shape analyses normalize for tooth size, potentially masking the relationship between relative food item size and tooth shape. Here, we model how relative food item size may affect optimal tooth cusp radius of curvature (RoC) during the fracture of brittle food items using a parametric finite-element (FE) model of a four-cusped molar. Morphospaces were created for four different food item sizes by altering cusp RoCs to determine whether optimal tooth shape changed as food item size changed. The morphospaces were also used to investigate whether variation in efficiency metrics (i.e. stresses, energy and optimality) changed as food item size changed. We found that optimal tooth shape changed as food item size changed, but that all optimal morphologies were similar, with one dull cusp that promoted high stresses in the food item and three cusps that acted to stabilize the food item. There were also positive relationships between food item size and the coefficients of variation for stresses in food item and optimality, and negative relationships between food item size and the coefficients of variation for stresses in the enamel and strain energy absorbed by the food item. These results suggest that relative food item size may play a role in selecting for optimal tooth shape, and the magnitude of these selective forces may change depending on food item size and which efficiency metric is being selected.

  9. Microcomputers: Instrument Generation Software. Evaluation Guides. Guide Number 11.

    Science.gov (United States)

    Gray, Peter J.

    Designed to assist evaluators in selecting the appropriate software for the generation of various data collection instruments, this guide discusses such key program characteristics as text entry, item storage and manipulation, item retrieval, and printing. Some characteristics of a good instrument generation program are discussed; these include…

  10. Dependability of technical items: Problems of standardization

    Science.gov (United States)

    Fedotova, G. A.; Voropai, N. I.; Kovalev, G. F.

    2016-12-01

    This paper is concerned with problems blown up in the development of a new version of the Interstate Standard GOST 27.002 "Industrial product dependability. Terms and definitions". This Standard covers a wide range of technical items and is used in numerous regulations, specifications, standard and technical documentation. A currently available State Standard GOST 27.002-89 was introduced in 1990. Its development involved a participation of scientists and experts from different technical areas, its draft was debated in different audiences and constantly refined, so it was a high quality document. However, after 25 years of its application it's become necessary to develop a new version of the Standard that would reflect the current understanding of industrial dependability, accounting for the changes taking place in Russia in the production, management and development of various technical systems and facilities. The development of a new version of the Standard makes it possible to generalize on a terminological level the knowledge and experience in the area of reliability of technical items, accumulated over a quarter of the century in different industries and reliability research schools, to account for domestic and foreign experience of standardization. Working on the new version of the Standard, we have faced a number of issues and problems on harmonization with the International Standard IEC 60500-192, caused first of all by different approaches to the use of terms and differences in the mentalities of experts from different countries. The paper focuses on the problems related to the chapter "Maintenance, restoration and repair", which caused difficulties for the developers to harmonize term definitions both with experts and the International Standard, which is mainly related to differences between the Russian concept and practice of maintenance and repair and foreign ones.

  11. Generation Speed in Raven's Progressive Matrices Test.

    Science.gov (United States)

    Verguts, Tom; De Boeck, Paul; Maris, Eric

    1999-01-01

    Studied the role of response fluency on results of the Raven's Advanced Progressive Matrices (APM) Test by comparing scores on a test of generation speed (speed of generating rules that govern the items) with APM test performance for 127 Belgian undergraduates. Discusses the importance of generation speed in intelligence. (SLD)

  12. Development and Validation of Written Exam Items for the Agricultural Hazardous Occupations Orders (AgHOs) Certification Training Program.

    Science.gov (United States)

    Mann, A J; Field, W E; Tormoehlen, R; French, B F

    2016-04-01

    Research was conducted to develop and validate a pool of exam items that can be used to test the readiness of youth, ages 14-15 years, to be certified under the current federally mandated Agricultural Hazardous Occupations Orders (AgHOs). The AgHOs require training prior to employment in agricultural workplaces that the Secretary of Labor has determined are especially hazardous for youth within the prescribed age range. Under the current provisions of the AgHOs certification process, non-exempt youth seeking employment in agriculture are required to pass a written exam concentrating on safe work practices as partial satisfaction to receive certification of eligibility for employment to perform certain tasks. However, the regulations provide little guidance concerning the format of the exam, subject matter to be covered, degree of difficulty, or minimum passing score. As part of the USDA-sponsored Hazardous Occupations Safety Training in Agriculture (HOSTA) initiative, efforts have been made to develop consistent and evidence-based testing methods for disseminating the test protocols to instructors. The goal was to expand, enhance, and maintain the reliability of the exam item pool for the AgHOs certification process. Item development was based on the HOSTA-supported Gearing Up for Safety: Production Agriculture Safety Training for Youth curriculum. To ensure adequate item availability, the current item pool was expanded to include a minimum of two test items for each of the 157 cognitive-based core competencies developed as part of the Gearing Up curriculum design process. Administering 70-item exams that were generated from the item pool to 568 youth, ages 13-18 years, provided evidence of item validity. The result was a pool of 367 validated exam items.

  13. The Prediction of TOEFL Reading Comprehension Item Difficulty for Expository Prose Passages for Three Item Types: Main Idea, Inference, and Supporting Idea Items.

    Science.gov (United States)

    Freedle, Roy; Kostin, Irene

    Prediction of the difficulty (equated delta) of a large sample (n=213) of reading comprehension items from the Test of English as a Foreign Language (TOEFL) was studied using main idea, inference, and supporting statement items. A related purpose was to examine whether text and text-related variables play a significant role in predicting item…

  14. Item Response Theory with Covariates (IRT-C): Assessing Item Recovery and Differential Item Functioning for the Three-Parameter Logistic Model

    Science.gov (United States)

    Tay, Louis; Huang, Qiming; Vermunt, Jeroen K.

    2016-01-01

    In large-scale testing, the use of multigroup approaches is limited for assessing differential item functioning (DIF) across multiple variables as DIF is examined for each variable separately. In contrast, the item response theory with covariate (IRT-C) procedure can be used to examine DIF across multiple variables (covariates) simultaneously. To…

  15. Exceptional Reductions

    CERN Document Server

    Marrani, Alessio; Riccioni, Fabio

    2011-01-01

    Starting from basic identities of the group E8, we perform progressive reductions, namely decompositions with respect to the maximal and symmetric embeddings of E7xSU(2) and then of E6xU(1). This procedure provides a systematic approach to the basic identities involving invariant primitive tensor structures of various irreprs. of finite-dimensional exceptional Lie groups. We derive novel identities for E7 and E6, highlighting the E8 origin of some well known ones. In order to elucidate the connections of this formalism to four-dimensional Maxwell-Einstein supergravity theories based on symmetric scalar manifolds (and related to irreducible Euclidean Jordan algebras, the unique exception being the triality-symmetric N = 2 stu model), we then derive a fundamental identity involving the unique rank-4 symmetric invariant tensor of the 0-brane charge symplectic irrepr. of U-duality groups, with potential applications in the quantization of the charge orbits of supergravity theories, as well as in the study of mult...

  16. Editorial Changes and Item Performance: Implications for Calibration and Pretesting

    Directory of Open Access Journals (Sweden)

    Heather Stoffel

    2014-11-01

    Full Text Available Previous research on the impact of text and formatting changes on test-item performance has produced mixed results. This matter is important because it is generally acknowledged that any change to an item requires that it be recalibrated. The present study investigated the effects of seven classes of stylistic changes on item difficulty, discrimination, and response time for a subset of 65 items that make up a standardized test for physician licensure completed by 31,918 examinees in 2012. One of two versions of each item (original or revised was randomly assigned to examinees such that each examinee saw only two experimental items, with each item being administered to approximately 480 examinees. The stylistic changes had little or no effect on item difficulty or discrimination; however, one class of edits -' changing an item from an open lead-in (incomplete statement to a closed lead-in (direct question -' did result in slightly longer response times. Data for nonnative speakers of English were analyzed separately with nearly identical results. These findings have implications for the conventional practice of repretesting (or recalibrating items that have been subjected to minor editorial changes.

  17. Item analysis of in use multiple choice questions in pharmacology

    Science.gov (United States)

    Kaur, Mandeep; Singla, Shweta; Mahajan, Rajiv

    2016-01-01

    Background: Multiple choice questions (MCQs) are a common method of assessment of medical students. The quality of MCQs is determined by three parameters such as difficulty index (DIF I), discrimination index (DI), and distracter efficiency (DE). Objectives: The objective of this study is to assess the quality of MCQs currently in use in pharmacology and discard the MCQs which are not found useful. Materials and Methods: A class test of central nervous system unit was conducted in the Department of Pharmacology. This test comprised 50 MCQs/items and 150 distracters. A correct response to an item was awarded one mark with no negative marking for incorrect response. Each item was analyzed for three parameters such as DIF I, DI, and DE. Results: DIF of 38 (76%) items was in the acceptable range (P = 30–70%), 11 (22%) items were too easy (P > 70%), and 1 (2%) item was too difficult (P 0.35), of 12 (24%) items was good (d = 0.20–0.34), and of 7 (14%) items was poor (d < 0.20). A total of 50 items had 150 distracters. Among these, 27 (18%) were nonfunctional distracters (NFDs) and 123 (82%) were functional distracters. Items with one NFD were 11 and with two NFDs were 8. Based on these parameters, 6 items were discarded, 17 were revised, and 27 were kept for subsequent use. Conclusion: Item analysis is a valuable tool as it helps us to retain the valuable MCQs and discard the items which are not useful. It also helps in increasing our skills in test construction and identifies the specific areas of course content which need greater emphasis or clarity. PMID:27563581

  18. Efficient Algorithms for Segmentation of Item-Set Time Series

    Science.gov (United States)

    Chundi, Parvathi; Rosenkrantz, Daniel J.

    We propose a special type of time series, which we call an item-set time series, to facilitate the temporal analysis of software version histories, email logs, stock market data, etc. In an item-set time series, each observed data value is a set of discrete items. We formalize the concept of an item-set time series and present efficient algorithms for segmenting a given item-set time series. Segmentation of a time series partitions the time series into a sequence of segments where each segment is constructed by combining consecutive time points of the time series. Each segment is associated with an item set that is computed from the item sets of the time points in that segment, using a function which we call a measure function. We then define a concept called the segment difference, which measures the difference between the item set of a segment and the item sets of the time points in that segment. The segment difference values are required to construct an optimal segmentation of the time series. We describe novel and efficient algorithms to compute segment difference values for each of the measure functions described in the paper. We outline a dynamic programming based scheme to construct an optimal segmentation of the given item-set time series. We use the item-set time series segmentation techniques to analyze the temporal content of three different data sets—Enron email, stock market data, and a synthetic data set. The experimental results show that an optimal segmentation of item-set time series data captures much more temporal content than a segmentation constructed based on the number of time points in each segment, without examining the item set data at the time points, and can be used to analyze different types of temporal data.

  19. Impacts of Newly Acquired Items Within Business Combinations on the Items of the Financial Statements

    Directory of Open Access Journals (Sweden)

    Jana Gláserová

    2016-01-01

    Full Text Available This paper is focused on the operations with the company (business combinations. These are those operations that are associated with the formation or dissolution of companies or reorganization of their ownership structure. They are often referred as equity transactions. In the concept of Czech accounting legislation, these are the purchase, sale, investment (deposit of firms or their parts, and various forms of transformation of enterprises. There are analyzed the accounting practices of recording of these issues under the Czech accounting legislation and International Financial Reporting Standards. Consequently there are identified newly acquired assets and liabilities arising directly in connection with the business combinations. In the conclusion of this paper there are examined the effects of different reporting of newly acquired items in the context of business combinations according to Czech accounting legislation and in accordance with International Financial Reporting Standards on the significant items of balance sheet and profit and loss statement from the material and time point of view.

  20. Hiding Sensitive Association Rules without Altering the Support of Sensitive Item(s)

    CERN Document Server

    Jain, Dhyanendra

    2012-01-01

    Association rule mining is an important data-mining technique that finds interesting association among a large set of data items. Since it may disclose patterns and various kinds of sensitive knowledge that are difficult to find otherwise, it may pose a threat to the privacy of discovered confidential information. Such information is to be protected against unauthorized access. Many strategies had been proposed to hide the information. Some use distributed databases over several sites, data perturbation, clustering, and data distortion techniques. Hiding sensitive rules problem, and still not sufficiently investigated, is the requirement to balance the confidentiality of the disclosed data with the legitimate needs of the user. The proposed approach uses the data distortion technique where the position of the sensitive items is altered but its support is never changed. The size of the database remains the same. It uses the idea of representative rules to prune the rules first and then hides the sensitive rule...

  1. Neonatal Facial Coding System for Assessing Postoperative Pain in Infants: Item Reduction is Valid and Feasible

    NARCIS (Netherlands)

    Peters, J.W.B.; Koot, H.M.; Grunau, R.E.; Boer, J. de; Druenen, M.J. van; Tibboel, D.; Duivenvoorden, H.J.

    2003-01-01

    Objective: The objectives of this study were to: (1) evaluate the validity of the Neonatal Facial Coding System (NFCS) for assessment of postoperative pain and (2) explore whether the number of NFCS facial actions could be reduced for assessing postoperative pain. Design: Prospective, observational

  2. A Demonstration of a Systematic Item-Reduction Approach Using Structural Equation Modeling

    Science.gov (United States)

    Larwin, Karen; Harvey, Milton

    2012-01-01

    Establishing model parsimony is an important component of structural equation modeling (SEM). Unfortunately, little attention has been given to developing systematic procedures to accomplish this goal. To this end, the current study introduces an innovative application of the jackknife approach first presented in Rensvold and Cheung (1999). Unlike…

  3. Neonatal Facial Coding System for Assessing Postoperative Pain in Infants: Item Reduction is Valid and Feasible

    NARCIS (Netherlands)

    Peters, J.W.B.; Koot, H.M.; Grunau, R.E.; Boer, J. de; Druenen, M.J. van; Tibboel, D.; Duivenvoorden, H.J.

    2003-01-01

    Objective: The objectives of this study were to: (1) evaluate the validity of the Neonatal Facial Coding System (NFCS) for assessment of postoperative pain and (2) explore whether the number of NFCS facial actions could be reduced for assessing postoperative pain. Design: Prospective, observational

  4. Human Nav1.6 Channels Generate Larger Resurgent Currents than Human Nav1.1 Channels, but the Navβ4 Peptide Does Not Protect Either Isoform from Use-Dependent Reduction.

    Directory of Open Access Journals (Sweden)

    Reesha R Patel

    Full Text Available Voltage-gated sodium channels are responsible for the initiation and propagation of action potentials (APs. Two brain isoforms, Nav1.1 and Nav1.6, have very distinct cellular and subcellular expression. Specifically, Nav1.1 is predominantly expressed in the soma and proximal axon initial segment of fast-spiking GABAergic neurons, while Nav1.6 is found at the distal axon initial segment and nodes of Ranvier of both fast-spiking GABAergic and excitatory neurons. Interestingly, an auxiliary voltage-gated sodium channel subunit, Navβ4, is also enriched in the axon initial segment of fast-spiking GABAergic neurons. The C-terminal tail of Navβ4 is thought to mediate resurgent sodium current, an atypical current that occurs immediately following the action potential and is predicted to enhance excitability. To better understand the contribution of Nav1.1, Nav1.6 and Navβ4 to high frequency firing, we compared the properties of these two channel isoforms in the presence and absence of a peptide corresponding to part of the C-terminal tail of Navβ4. We used whole-cell patch clamp recordings to examine the biophysical properties of these two channel isoforms in HEK293T cells and found several differences between human Nav1.1 and Nav1.6 currents. Nav1.1 channels exhibited slower closed-state inactivation but faster open-state inactivation than Nav1.6 channels. We also observed a greater propensity of Nav1.6 to generate resurgent currents, most likely due to its slower kinetics of open-state inactivation, compared to Nav1.1. These two isoforms also showed differential responses to slow and fast AP waveforms, which were altered by the Navβ4 peptide. Although the Navβ4 peptide substantially increased the rate of recovery from apparent inactivation, Navβ4 peptide did not protect either channel isoform from undergoing use-dependent reduction with 10 Hz step-pulse stimulation or trains of slow or fast AP waveforms. Overall, these two channels have

  5. Binary classification of items of interest in a repeatable process

    Science.gov (United States)

    Abell, Jeffrey A.; Spicer, John Patrick; Wincek, Michael Anthony; Wang, Hui; Chakraborty, Debejyo

    2014-06-24

    A system includes host and learning machines in electrical communication with sensors positioned with respect to an item of interest, e.g., a weld, and memory. The host executes instructions from memory to predict a binary quality status of the item. The learning machine receives signals from the sensor(s), identifies candidate features, and extracts features from the candidates that are more predictive of the binary quality status relative to other candidate features. The learning machine maps the extracted features to a dimensional space that includes most of the items from a passing binary class and excludes all or most of the items from a failing binary class. The host also compares the received signals for a subsequent item of interest to the dimensional space to thereby predict, in real time, the binary quality status of the subsequent item of interest.

  6. The basics of item response theory using R

    CERN Document Server

    Baker, Frank B

    2017-01-01

    This graduate-level textbook is a tutorial for item response theory that covers both the basics of item response theory and the use of R for preparing graphical presentation in writings about the theory. Item response theory has become one of the most powerful tools used in test construction, yet one of the barriers to learning and applying it is the considerable amount of sophisticated computational effort required to illustrate even the simplest concepts. This text provides the reader access to the basic concepts of item response theory freed of the tedious underlying calculations. It is intended for those who possess limited knowledge of educational measurement and psychometrics. Rather than presenting the full scope of item response theory, this textbook is concise and practical and presents basic concepts without becoming enmeshed in underlying mathematical and computational complexities. Clearly written text and succinct R code allow anyone familiar with statistical concepts to explore and apply item re...

  7. Differential functioning of Bender Visual-Motor Gestalt Test items.

    Science.gov (United States)

    Sisto, Fermino Fernandes; Dos Santos, Acácia Aparecida Angeli; Noronha, Ana Paula Porto

    2010-02-01

    Differential Item Functioning (DIF) refers to items that do not function the same way for comparable members of different groups. The present study focuses on analyzing and classifying sex-related differential item functioning in the Bender Visual-Motor Gestalt Test. Subjects were 1,052 children attending public schools (513 boys, 539 girls, ages 6-10 years). The protocols were scored using the Bender Graduated Scoring System, which evaluates only the distortion criterion using the Rasch logistic response model. The scoring system fit the Rasch model, although two items were found to be biased by sex. When analyzing differential functioning of items for boys and girls separately, the number of differentially functioning items was equal.

  8. Promoting cold-start items in recommender systems

    CERN Document Server

    Liu, Jin-Hu; Zhang, Zi-Ke; Yang, Zimo; Liu, Chuang; Li, Wei-Min

    2014-01-01

    As one of major challenges, cold-start problem plagues nearly all recommender systems. In particular, new items will be overlooked, impeding the development of new products online. Given limited resources, how to utilize the knowledge of recommender systems and design efficient marketing strategy for new items is extremely important. In this paper, we convert this ticklish issue into a clear mathematical problem based on a bipartite network representation. Under the most widely used algorithm in real e-commerce recommender systems, so-called the item-based collaborative filtering, we show that to simply push new items to active users is not a good strategy. To our surprise, experiments on real recommender systems indicate that to connect new items with some less active users will statistically yield better performance, namely these new items will have more chance to appear in other users' recommendation lists. Further analysis suggests that the disassortative nature of recommender systems contributes to such ...

  9. The Body Appreciation Scale-2: item refinement and psychometric evaluation.

    Science.gov (United States)

    Tylka, Tracy L; Wood-Barcalow, Nichole L

    2015-01-01

    Considered a positive body image measure, the 13-item Body Appreciation Scale (BAS; Avalos, Tylka, & Wood-Barcalow, 2005) assesses individuals' acceptance of, favorable opinions toward, and respect for their bodies. While the BAS has accrued psychometric support, we improved it by rewording certain BAS items (to eliminate sex-specific versions and body dissatisfaction-based language) and developing additional items based on positive body image research. In three studies, we examined the reworded, newly developed, and retained items to determine their psychometric properties among college and online community (Amazon Mechanical Turk) samples of 820 women and 767 men. After exploratory factor analysis, we retained 10 items (five original BAS items). Confirmatory factor analysis upheld the BAS-2's unidimensionality and invariance across sex and sample type. Its internal consistency, test-retest reliability, and construct (convergent, incremental, and discriminant) validity were supported. The BAS-2 is a psychometrically sound positive body image measure applicable for research and clinical settings.

  10. OPTIMIZING HIGHWAY PROFILES FOR INDIVIDUAL COST ITEMS

    Directory of Open Access Journals (Sweden)

    Essam Dabbour

    2013-12-01

    Full Text Available According to the current practice, vertical alignment of a highway segment is usually selected by creating a profile showing the actual ground surface and selecting initial and final grades to minimize the overall cut and fill quantities. Those grades are connected together with a parabolic curve. However, in many highway construction or rehabilitation projects, the cost of cut may be substantially different from that of fill (e.g. in extremely hard soils where blasting is needed to cut the soil. In that case, an optimization process will be needed to minimize the overall cost of cut and fill rather than to minimize their quantities. This paper proposes a nonlinear optimization model to select optimum vertical curve parameters based on individual cost items of cut and fill. The parameters selected by the optimization model include the initial grade, the final grade, the station and elevation of the point of vertical curvature (PVC, and the station and elevation of the point of vertical tangency (PVT. The model is flexible to include any design constraints for particular design problems. Different application examples are provided using the Evolutionary Algorithm in Microsoft Excel’s Solver add-in. The application examples validated the model and demonstrated its advantage of minimizing the overall cost rather than minimizing the overall volume of cut and fill quantities.

  11. Percent Errors in the Estimation of Demand for Secondary Items.

    Science.gov (United States)

    1985-11-01

    percent errors, and the program change factor (PCF) to predict item demana during the procurement *’ leadtime (PROLT) ior the item. The PCF accounts for...type of demand it was. It may"-- have been demanded over two years ago or it may nave been a non-recurring demana . Since CC b only retains two years of...observed distributions could be compared with negative binomial distributions. For each item the computed ratio of actual demana to expected demand was

  12. Safety Evaluation for Packaging (onsite) T Plant Canyon Items

    Energy Technology Data Exchange (ETDEWEB)

    OBRIEN, J.H.

    2000-07-14

    This safety evaluation for packaging (SEP) evaluates and documents the ability to safely ship mostly unique inventories of miscellaneous T Plant canyon waste items (T-P Items) encountered during the canyon deck clean off campaign. In addition, this SEP addresses contaminated items and material that may be shipped in a strong tight package (STP). The shipments meet the criteria for onsite shipments as specified by Fluor Hanford in HNF-PRO-154, Responsibilities and Procedures for all Hazardous Material Shipments.

  13. Assessing the quality of multiple-choice test items.

    Science.gov (United States)

    Clifton, Sandra L; Schriner, Cheryl L

    2010-01-01

    With the focus of nursing education geared toward teaching students to think critically, faculty need to assure that test items require students to use a high level of cognitive processing. To evaluate their examinations, the authors assessed multiple-choice test items on final nursing examinations. The assessment included determining cognitive learning levels and frequency of items among 3 adult health courses, comparing difficulty values with cognitive learning levels, and examining discrimination values and the relationship to distracter performance.

  14. Three controversies over item disclosure in medical licensure examinations

    Directory of Open Access Journals (Sweden)

    Yoon Soo Park

    2015-09-01

    Full Text Available In response to views on public's right to know, there is growing attention to item disclosure – release of items, answer keys, and performance data to the public – in medical licensure examinations and their potential impact on the test's ability to measure competence and select qualified candidates. Recent debates on this issue have sparked legislative action internationally, including South Korea, with prior discussions among North American countries dating over three decades. The purpose of this study is to identify and analyze three issues associated with item disclosure in medical licensure examinations – 1 fairness and validity, 2 impact on passing levels, and 3 utility of item disclosure – by synthesizing existing literature in relation to standards in testing. Historically, the controversy over item disclosure has centered on fairness and validity. Proponents of item disclosure stress test takers’ right to know, while opponents argue from a validity perspective. Item disclosure may bias item characteristics, such as difficulty and discrimination, and has consequences on setting passing levels. To date, there has been limited research on the utility of item disclosure for large scale testing. These issues requires ongoing and careful consideration.

  15. Embodied Valuation: Directional Action is Associated with Item Values.

    Science.gov (United States)

    Green, Danielle J; Harris, Alison; Young, Aleena; Reed, Catherine L

    2017-08-31

    We have a lifetime of experience interacting with objects we value. Although many economic theories represent valuation as a purely cognitive process independent of the sensorimotor system, embodied cognitive theory suggests that our memories for items' value should be linked to actions we use to obtain them. Here we investigated whether the value of real items was associated with specific directional movements toward or away from the body. Participants priced a set of food items to determine their values; they then used directional actions to classify each item as high- or low-value. To determine if value is linked to specific action mappings, movements were referenced either with respect to the object (push toward high-value items; pull away from low-value items) or the self (pull high-value items toward self; push low-value items away). Participants who were assigned (Experiment 1) or chose (Experiment 2) to use an object-referenced action mapping were faster than those using a self-referenced mapping. A control experiment (Experiment 3) using left/right movements found no such difference when action mappings were not toward/away from the body. These results indicate that directional actions towards items are associated with the representation of their value, suggesting an embodied component to economic choice.

  16. [Perceptions on item disclosure for the Korean medical licensing examination].

    Science.gov (United States)

    Yang, Eunbae B

    2015-09-01

    This study analyzed the perceptions of medical students and faculty regarding disclosure of test items on the Korean medical licensing examination. I conducted a survey of medical students from medical colleges and professional medical schools nationwide. Responses were analyzed from 718 participants as well as 69 faculty members who participated in creating the medical licensing examination item sets. Data were analyzed using descriptive statistics and the chi-square test. It is important to maintain test quality and to keep the test items unavailable to the public. There are also concerns among students that disclosure of test items would prompt increasing difficulty of test items (48.3%). Further, few students found it desirable to disclose test items regardless of any considerations (28.5%). The professors, who had experience in designing the test items, also expressed their opposition to test item disclosure (60.9%). It is desirable not to disclose the test items of the Korean medical licensing examination to the public on the condition that students are provided with a sufficient amount of information regarding the examination. This is so that the exam can appropriately identify candidates with the required qualifications.

  17. Reducing air pollution from electricity-generating large combustion plants in the European Union. An assessment of potential emission reductions of NO{sub X}, SO{sub 2} and dust

    Energy Technology Data Exchange (ETDEWEB)

    Lodewijks, P.; Pieper, H.; Van Wortswinkel, L. [ETC partner Flemish Institute for Technological Research (VITO) (Belgium); Boyce, B.; Adams, M.; Goossens, E. [EEA, Copenhagen (Denmark)

    2013-06-15

    An assessment of potential emission reductions of NO{sub X}, SO{sub 2} and dust - This report presents an assessment of the hypothetical emission reduction potential of NO{sub x}, SO{sub 2} and dust from more than 1 500 of Europe's large combustion plants that operated in 2009. Emissions of these air pollutants could be significantly lower if all plants were to meet the emission limit values as set out in European Union legislation. (Author)

  18. Development of a self-report physical function instrument for disability assessment: item pool construction and factor analysis.

    Science.gov (United States)

    McDonough, Christine M; Jette, Alan M; Ni, Pengsheng; Bogusz, Kara; Marfeo, Elizabeth E; Brandt, Diane E; Chan, Leighton; Meterko, Mark; Haley, Stephen M; Rasch, Elizabeth K

    2013-09-01

    To build a comprehensive item pool representing work-relevant physical functioning and to test the factor structure of the item pool. These developmental steps represent initial outcomes of a broader project to develop instruments for the assessment of function within the context of Social Security Administration (SSA) disability programs. Comprehensive literature review; gap analysis; item generation with expert panel input; stakeholder interviews; cognitive interviews; cross-sectional survey administration; and exploratory and confirmatory factor analyses to assess item pool structure. In-person and semistructured interviews and Internet and telephone surveys. Sample of SSA claimants (n=1017) and a normative sample of adults from the U.S. general population (n=999). Not applicable. Model fit statistics. The final item pool consisted of 139 items. Within the claimant sample, 58.7% were white; 31.8% were black; 46.6% were women; and the mean age was 49.7 years. Initial factor analyses revealed a 4-factor solution, which included more items and allowed separate characterization of: (1) changing and maintaining body position, (2) whole body mobility, (3) upper body function, and (4) upper extremity fine motor. The final 4-factor model included 91 items. Confirmatory factor analyses for the 4-factor models for the claimant and the normative samples demonstrated very good fit. Fit statistics for claimant and normative samples, respectively, were: Comparative Fit Index=.93 and .98; Tucker-Lewis Index=.92 and .98; and root mean square error approximation=.05 and .04. The factor structure of the physical function item pool closely resembled the hypothesized content model. The 4 scales relevant to work activities offer promise for providing reliable information about claimant physical functioning relevant to work disability. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  19. Item response theory-based measure of global disability in multiple sclerosis derived from the Performance Scales and related items.

    Science.gov (United States)

    Chamot, Eric; Kister, Ilya; Cutter, Gary R

    2014-10-03

    The eight Performance Scales and three assimilated scales (PS) used in North American Research Committee on Multiple Sclerosis (NARCOMS) registry surveys cover a broad range of neurologic domains commonly affected by multiple sclerosis (mobility, hand function, vision, fatigue, cognition, bladder/bowel, sensory, spasticity, pain, depression, and tremor/coordination). Each scale consists of a single 6-to-7-point Likert item with response categories ranging from "normal" to "total disability". Relatively little is known about the performances of the summary index of disability derived from these scales (the Performance Scales Sum or PSS). In this study, we demonstrate the value of a combination of classical and modern methods recently proposed by the Patient-Reported Outcome Measurement Information System (PROMIS) network to evaluate the psychometric properties of the PSS and derive an improved measure of global disability from the PS. The study sample included 7,851adults with MS who completed a NARCOMS intake questionnaire between 2003 and 2011. Factor analysis, bifactor modeling, and item response theory (IRT) analysis were used to evaluate the dimension(s) of disability underlying the PS; calibrate the 11 scales; and generate three alternative summary scores of global disability corresponding to different model assumptions and practical priorities. The construct validity of the three scores was compared by examining the magnitude of their associations with participant's background characteristics, including unemployment. We derived structurally valid measures of global disability from the PS through the proposed methodology that were superior to the PSS. The measure most applicable to clinical practice gives similar weight to physical and mental disability. Overall reliability of the new measure is acceptable for individual comparisons (0.87). Higher scores of global disability were significantly associated with older age at assessment, longer disease duration

  20. Conditional recall and the frequency effect in the serial recall task: an examination of item-to-item associativity.

    Science.gov (United States)

    Miller, Leonie M; Roodenrys, Steven

    2012-11-01

    The frequency effect in short-term serial recall is influenced by the composition of lists. In pure lists, a robust advantage in the recall of high-frequency (HF) words is observed, yet in alternating mixed lists, HF and low-frequency (LF) words are recalled equally well. It has been argued that the preexisting associations between all list items determine a single, global level of supportive activation that assists item recall. Preexisting associations between items are assumed to be a function of language co-occurrence; HF-HF associations are high, LF-LF associations are low, and mixed associations are intermediate in activation strength. This account, however, is based on results when alternating lists with equal numbers of HF and LF words were used. It is possible that directional association between adjacent list items is responsible for the recall patterns reported. In the present experiment, the recall of three forms of mixed lists-those with equal numbers of HF and LF items and pure lists-was examined to test the extent to which item-to-item associations are present in serial recall. Furthermore, conditional probabilities were used to examine more closely the evidence for a contribution, since correct-in-position scoring may mask recall that is dependent on the recall of prior items. The results suggest that an item-to-item effect is clearly present for early but not late list items, and they implicate an additional factor, perhaps the availability of resources at output, in the recall of late list items.

  1. Measurement Assurance for End-Item Users

    Science.gov (United States)

    Mimbs, Scott M.

    2008-01-01

    The goal of a Quality Management System (QMS) as specified in ISO 9001 and AS9100 is to assure the end product meets specifications and customer requirements. Measuring devices, often called measuring and test equipments (MTE), provide the evidence of product conformity to the prescribed requirements. Therefore the processes which employ MTE can become a weak link to the overall QMS if proper attention is not given to development and execution of these processes. Traditionally, calibration of MTE is given more focus in industry standards and process control efforts than the equally important proper usage of the same equipment. It is a common complaint of calibration laboratory personnel that MTE users are only interested in "a sticker." If the QMS requires the MTE "to demonstrate conformity of the product," then the quality of the measurement process must be adequate for the task. This leads to an ad hoc definition; measurement assurance is a discipline that assures that all processes, activities, environments, standards, and procedures involved in making a measurement produce a result that can be rigorously evaluated for validity and accuracy. To evaluate that the existing measurement processes are providing an adequate level of quality to support the decisions based upon this measurement data, an understanding of measurement assurance basics is essential. This topic is complimentary to the calibration standard, ANSI/NCSL Z540.3-2006, which targets the calibration of MTE at the organizational level. This paper will discuss general measurement assurance when MTE is used to provide evidence of product conformity, therefore the target audience of this paper is end item users of MTE. A central focus of the paper will be the verification of tolerances and the associated risks, so calibration professionals may find the paper useful in communication with their customers, MTE users.

  2. Creation of New Items and Forms for the Project A Assembling Objects Test

    Science.gov (United States)

    1994-08-01

    correct; D, a measure of item discrimination - the rpbi , between the item score (correct or incorrect) and the total score on the 36 original items...D2 another measure of item discrimination - the rpbis between the item score and the total score on the 18 original items of the same type (marked

  3. Item Purification Does Not Always Improve DIF Detection: A Counterexample with Angoff's Delta Plot

    Science.gov (United States)

    Magis, David; Facon, Bruno

    2013-01-01

    Item purification is an iterative process that is often advocated as improving the identification of items affected by differential item functioning (DIF). With test-score-based DIF detection methods, item purification iteratively removes the items currently flagged as DIF from the test scores to get purified sets of items, unaffected by DIF. The…

  4. Measuring the quality of life in hypertension according to Item Response Theory.

    Science.gov (United States)

    Borges, José Wicto Pereira; Moreira, Thereza Maria Magalhães; Schmitt, Jeovani; Andrade, Dalton Francisco de; Barbetta, Pedro Alberto; Souza, Ana Célia Caetano de; Lima, Daniele Braz da Silva; Carvalho, Irialda Saboia

    2017-05-04

    To analyze the Miniquestionário de Qualidade de Vida em Hipertensão Arterial (MINICHAL - Mini-questionnaire of Quality of Life in Hypertension) using the Item Response Theory. This is an analytical study conducted with 712 persons with hypertension treated in thirteen primary health care units of Fortaleza, State of Ceará, Brazil, in 2015. The steps of the analysis by the Item Response Theory were: evaluation of dimensionality, estimation of parameters of items, and construction of scale. The study of dimensionality was carried out on the polychoric correlation matrix and confirmatory factor analysis. To estimate the item parameters, we used the Gradual Response Model of Samejima. The analyses were conducted using the free software R with the aid of psych and mirt. The analysis has allowed the visualization of item parameters and their individual contributions in the measurement of the latent trait, generating more information and allowing the construction of a scale with an interpretative model that demonstrates the evolution of the worsening of the quality of life in five levels. Regarding the item parameters, the items related to the somatic state have had a good performance, as they have presented better power to discriminate individuals with worse quality of life. The items related to mental state have been those which contributed with less psychometric data in the MINICHAL. We conclude that the instrument is suitable for the identification of the worsening of the quality of life in hypertension. The analysis of the MINICHAL using the Item Response Theory has allowed us to identify new sides of this instrument that have not yet been addressed in previous studies. Analisar o Miniquestionário de Qualidade de Vida em Hipertensão Arterial (MINICHAL) por meio da Teoria da Resposta ao Item. Estudo analítico realizado com 712 pessoas com hipertensão arterial atendidas em 13 unidades de atenção primária em saúde de Fortaleza, CE, em 2015. As etapas da an

  5. Economic order quantity model for deteriorating items with imperfect quality and permissible delay on payment

    Directory of Open Access Journals (Sweden)

    Chandra K. Jaggi

    2011-04-01

    Full Text Available In the classical inventory models, most of the time the issue of quality has not been considered. However, in realistic environment, it can be observed that there may be some defective items in an ordered lot, because of these defective items retailer incurs additional cost due to rejection, repair and refund etc. Thus, inspection/screening of lot becomes indispensible in most of the organizations. Moreover, it plays a very essential role when items are of deteriorating in nature. Further, it is generally assumed that payment will be made to the supplier for the goods immediately after receiving the consignment. Whereas, in practice, supplier does offers a certain fixed period to the retailer for settling the account. During this period, supplier charges no interest, but beyond this period interest is being charged as has been agreed upon. On the other hand, retailer can earn interest on the revenue generated during this period. Keeping this scenario in mind, an attempt has been made to formulate an inventory model for deteriorating items with imperfect quality under permissible delay in payments. Results have been validated with the help of a numerical example using Matlab7.0.1. Comprehensive sensitivity analysis has also been presented.

  6. To call a cloud ‘cirrus’: sound symbolism in names for categories or items

    Science.gov (United States)

    Sučević, Jelena; Styles, Suzy J.

    2017-01-01

    The aim of the present paper is to experimentally test whether sound symbolism has selective effects on labels with different ranges-of-reference within a simple noun-hierarchy. In two experiments, adult participants learned the make up of two categories of unfamiliar objects (‘alien life forms’), and were passively exposed to either category-labels or item-labels, in a learning-by-guessing categorization task. Following category training, participants were tested on their visual discrimination of object pairs. For different groups of participants, the labels were either congruent or incongruent with the objects. In Experiment 1, when trained on items with individual labels, participants were worse (made more errors) at detecting visual object mismatches when trained labels were incongruent. In Experiment 2, when participants were trained on items in labelled categories, participants were faster at detecting a match if the trained labels were congruent, and faster at detecting a mismatch if the trained labels were incongruent. This pattern of results suggests that sound symbolism in category labels facilitates later similarity judgments when congruent, and discrimination when incongruent, whereas for item labels incongruence generates error in judgements of visual object differences. These findings reveal that sound symbolic congruence has a different outcome at different levels of labelling within a noun hierarchy. These effects emerged in the absence of the label itself, indicating subtle but pervasive effects on visual object processing. PMID:28674648

  7. Conditional Versus Unconditional Procedures for Sample-Free Item Analysis

    Science.gov (United States)

    Wright, Benjamin D.; Douglas, Graham A.

    1977-01-01

    Two procedures for Rasch, sample-free item calibration are reviewed and compared for accuracy. The theoretically ideal "conditional" procedure is impractical for more than fifteen items. The more practical but biased "unconditional" procedure is discussed in detail. (Author/JKS)

  8. Item-Specific and Interitem Elaboration in Recall and Recognition

    Science.gov (United States)

    1984-07-01

    However, increasing task difficulty, resulting in a more istinctive encoding for items, plays a larger role in recognition. In a similar vein, Belleza ...and his collegues ( Belleza , Cheesman & Reddy 1977) have demonstrated that organizational strategies, such as the alphabet and story mnemonics, aid...specific semantic processing (Craik & Tulving, 1975). Presumably, some item-specific semantic processing occurs prior to or during organization ( Belleza

  9. 26 CFR 1.461-5 - Recurring item exception.

    Science.gov (United States)

    2010-04-01

    ... satisfied, generally accepted accounting principles are an important factor, but are not dispositive. (ii... of accounting may adopt the recurring item exception described in paragraph (b) of this section as method of accounting for one or more types of recurring items incurred by the taxpayer. In the case...

  10. 48 CFR 252.211-7003 - Item identification and valuation.

    Science.gov (United States)

    2010-10-01

    ... in this clause— Automatic identification device means a device, such as a reader or interrogator... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Item identification and... of Provisions And Clauses 252.211-7003 Item identification and valuation. As prescribed in 211.274-6...

  11. Semiparametric Item Response Functions in the Context of Guessing

    Science.gov (United States)

    Falk, Carl F.; Cai, Li

    2016-01-01

    We present a logistic function of a monotonic polynomial with a lower asymptote, allowing additional flexibility beyond the three-parameter logistic model. We develop a maximum marginal likelihood-based approach to estimate the item parameters. The new item response model is demonstrated on math assessment data from a state, and a computationally…

  12. 17 CFR 229.10 - (Item 10) General.

    Science.gov (United States)

    2010-04-01

    ... Corporate governance. Item 503 Prospectus summary, risk factors, and ratio of earnings to fixed charges... term is defined in Item 1101 of Regulation AB (§ 229.1101)), reference may not be made to any document... this part, the term smaller reporting company means an issuer that is not an investment company,...

  13. A nonparametric approach to the analysis of dichotomous item responses

    NARCIS (Netherlands)

    Mokken, R.J.; Lewis, C.

    1982-01-01

    An item response theory is discussed which is based on purely ordinal assumptions about the probabilities that people respond positively to items. It is considered as a natural generalization of both Guttman scaling and classical test theory. A distinction is drawn between construction and evaluatio

  14. Do item-writing flaws reduce examinations psychometric quality?

    Science.gov (United States)

    Pais, João; Silva, Artur; Guimarães, Bruno; Povo, Ana; Coelho, Elisabete; Silva-Pereira, Fernanda; Lourinho, Isabel; Ferreira, Maria Amélia; Severo, Milton

    2016-08-11

    The psychometric characteristics of multiple-choice questions (MCQ) changed when taking into account their anatomical sites and the presence of item-writing flaws (IWF). The aim is to understand the impact of the anatomical sites and the presence of IWF in the psychometric qualities of the MCQ. 800 Clinical Anatomy MCQ from eight examinations were classified as standard or flawed items and according to one of the eight anatomical sites. An item was classified as flawed if it violated at least one of the principles of item writing. The difficulty and discrimination indices of each item were obtained. 55.8 % of the MCQ were flawed items. The anatomical site of the items explained 6.2 and 3.2 % of the difficulty and discrimination parameters and the IWF explained 2.8 and 0.8 %, respectively. The impact of the IWF was heterogeneous, the Writing the Stem and Writing the Choices categories had a negative impact (higher difficulty and lower discrimination) while the other categories did not have any impact. The anatomical site effect was higher than IWF effect in the psychometric characteristics of the examination. When constructing MCQ, the focus should be in the topic/area of the items and only after in the presence of IWF.

  15. Mathematical-programming approaches to test item pool design

    NARCIS (Netherlands)

    Veldkamp, Bernard P.; van der Linden, Willem J.; Ariel, A.

    2002-01-01

    This paper presents an approach to item pool design that has the potential to improve on the quality of current item pools in educational and psychological testing andhence to increase both measurement precision and validity. The approach consists of the application of mathematical programming

  16. Using response times for item selection in adaptive testing

    NARCIS (Netherlands)

    Linden, van der Wim J.

    2008-01-01

    Response times on items can be used to improve item selection in adaptive testing provided that a probabilistic model for their distribution is available. In this research, the author used a hierarchical modeling framework with separate first-level models for the responses and response times and a s

  17. Detecting Local Item Dependence in Polytomous Adaptive Data

    Science.gov (United States)

    Mislevy, Jessica L.; Rupp, Andre A.; Harring, Jeffrey R.

    2012-01-01

    A rapidly expanding arena for item response theory (IRT) is in attitudinal and health-outcomes survey applications, often with polytomous items. In particular, there is interest in computer adaptive testing (CAT). Meeting model assumptions is necessary to realize the benefits of IRT in this setting, however. Although initial investigations of…

  18. Distributed Item Review: Administrator User Guide. Technical Report #1603

    Science.gov (United States)

    Irvin, P. Shawn

    2016-01-01

    The Distributed Item Review (DIR) is a secure and flexible, web-based system designed to present test items to expert reviewers across a broad geographic area for evaluation of important dimensions of quality (e.g., alignment with standards, bias, sensitivity, and student accessibility). The DIR is comprised of essential features that allow system…

  19. Automated addition of Chelex solution to tubes containing trace items

    DEFF Research Database (Denmark)

    Stangegaard, Michael; Hansen, Thomas Møller; Hansen, Anders Johannes;

    2011-01-01

    Extraction of DNA from trace items for forensic genetic DNA typing using a manual Chelex based extraction protocol requires addition of Chelex solution to sample tubes containing trace items. Automated of addition of Chelex solution may be hampered by high viscosity of the solution and fast sedim...

  20. Lower-fat menu items in restaurants satisfy customers.

    Science.gov (United States)

    Fitzpatrick, M P; Chapman, G E; Barr, S I

    1997-05-01

    To evaluate a restaurant-based nutrition program by measuring customer satisfaction with lower-fat menu items and assessing patrons' reactions to the program. Questionnaires to assess satisfaction with menu items were administered to patrons in eight of the nine restaurants that volunteered to participate in the nutrition program. One patron from each participating restaurant was randomly selected for a semistructured interview about nutrition programming in restaurants. Persons dining in eight participating restaurants over a 1-week period (n = 686). Independent samples t tests were used to compare respondents' satisfaction with lower-fat and regular menu items. Two-way analysis of variance tests were completed using overall satisfaction as the dependent variable and menu-item classification (ie, lower fat or regular) and one of eight other menu item and respondent characteristics as independent variables. Qualitative methods were used to analyze interview transcripts. Of 1,127 menu items rated for satisfaction, 205 were lower fat, 878 were regular, and 44 were of unknown classification. Customers were significantly more satisfied with lower-fat than with regular menu items (P satisfaction did not vary by any of the other independent variables. Interview results indicate the importance of restaurant during as an indulgent experience. High satisfaction with lower-fat menu items suggests that customers will support restaurant providing such choices. Dietitians can use these findings to encourage restaurateurs to include lower-fat choices on their menus, and to assure clients that their expectations of being indulged are not incompatible with these choices.

  1. Effects of clinical practice focusing on level-3 OSCE items.

    Science.gov (United States)

    Sakurai, Hiroaki; Kanada, Yoshikiyo; Sugiura, Yoshito; Motoya, Ikuo; Wada, Yosuke; Yamada, Masayuki; Tomita, Masao; Tanabe, Shigeo; Koyama, Soichiro; Teranishi, Toshio; Sawa, Syunji; Okanishi, Tetsuo

    2015-05-01

    [Purpose] This study examined the effects of clinical training focusing on level-3 OSCE (analytical and therapeutic skills) items, and compared the achievement levels of physical (PT) and occupational (OT) therapist students. [Subjects] A total of 282 (165 PT and 117 OT) students enrolled at our university between 2008 and 2010 were studied. [Methods] OSCE scores were compared between before and after clinical training focusing on level-3 OSCE items, and between PT and OT students. [Results] Scores for 5 out of the 6 level-3a items were significantly higher after than before clinical training. Increases in scores of 2 or 3 level-3b and -3c items were also observed after clinical training. There were no marked differences between PT and OT students in scores for level-3a, -3b, and -3c items before clinical training. In contrast, after clinical training, OT students' scores for 3a and 3c items related to dressing were higher than those of PT students, and the latter's scores for 3b items related to transfer were higher than those of the former. [Conclusion] The results suggest level-3 OSCE items are effectively taught during clinical training.

  2. 48 CFR 211.105 - Items peculiar to one manufacturer.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Items peculiar to one manufacturer. 211.105 Section 211.105 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS... Requirements Documents 211.105 Items peculiar to one manufacturer. Follow the publication requirements at...

  3. 48 CFR 811.105 - Items peculiar to one manufacturer.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Items peculiar to one manufacturer. 811.105 Section 811.105 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS... 811.105 Items peculiar to one manufacturer. (a) Except as provided in paragraph (b) of this...

  4. Group differences in the heritability of items and test scores

    NARCIS (Netherlands)

    Wicherts, J.M.; Johnson, W.

    2009-01-01

    It is important to understand potential sources of group differences in the heritability of intelligence test scores. On the basis of a basic item response model we argue that heritabilities which are based on dichotomous item scores normally do not generalize from one sample to the next. If groups

  5. Individuality of Item Interpretation in Interchangeable ACL Scales

    Science.gov (United States)

    Fiske, Donald W.; Barack, Leonard I.

    1976-01-01

    The diversity among interpretations of single items in personality questionnaires has been noted previously. Using adjectives from the Adjective Check List (ACL), the study sought evidence bearing on these questions: Does such diversity make the responses to an item not comparable across subjects? If so, what are the implications for scores based…

  6. 32 CFR 643.51 - Additional items concerning leasing.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Additional items concerning leasing. 643.51... PROPERTY REAL ESTATE Leases § 643.51 Additional items concerning leasing. In addition to the general and... leasing of Army real estate....

  7. Characterizing Sources of Uncertainty in Item Response Theory Scale Scores

    Science.gov (United States)

    Yang, Ji Seung; Hansen, Mark; Cai, Li

    2012-01-01

    Traditional estimators of item response theory scale scores ignore uncertainty carried over from the item calibration process, which can lead to incorrect estimates of the standard errors of measurement (SEMs). Here, the authors review a variety of approaches that have been applied to this problem and compare them on the basis of their statistical…

  8. 7 CFR 65.220 - Processed food item.

    Science.gov (United States)

    2010-01-01

    ... AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) COUNTRY OF ORIGIN LABELING..., PEANUTS, AND GINSENG General Provisions Definitions § 65.220 Processed food item. Processed food item... further step in the preparation of the product for consumption, would not in itself result in a processed...

  9. Negative Affect Impairs Associative Memory but Not Item Memory

    Science.gov (United States)

    Bisby, James A.; Burgess, Neil

    2014-01-01

    The formation of associations between items and their context has been proposed to rely on mechanisms distinct from those supporting memory for a single item. Although emotional experiences can profoundly affect memory, our understanding of how it interacts with different aspects of memory remains unclear. We performed three experiments to examine…

  10. Dissociation between source and item memory in Parkinson's disease

    Institute of Scientific and Technical Information of China (English)

    Hu Panpan; Li Youhai; Ma Huijuan; Xi Chunhua; Chen Xianwen; Wang Kai

    2014-01-01

    Background Episodic memory includes information about item memory and source memory.Many researches support the hypothesis that these two memory systems are implemented by different brain structures.The aim of this study was to investigate the characteristics of item memory and source memory processing in patients with Parkinson's disease (PD),and to further verify the hypothesis of dual-process model of source and item memory.Methods We established a neuropsychological battery to measure the performance of item memory and source memory.Totally 35 PD individuals and 35 matched healthy controls (HC) were administrated with the battery.Item memory task consists of the learning and recognition of high-frequency national Chinese characters; source memory task consists of the learning and recognition of three modes (character,picture,and image) of objects.Results Compared with the controls,the idiopathic PD patients have been impaired source memory (PD vs.HC:0.65±0.06 vs.0.72±0.09,P=0.001),but not impaired in item memory (PD vs.HC:0.65±0.07 vs.0.67±0.08,P=0.240).Conclusions The present experiment provides evidence for dissociation between item and source memory in PD patients,thereby strengthening the claim that the item or source memory rely on different brain structures.PD patients show poor source memory,in which dopamine plays a critical role.

  11. Elu kui näitemäng / Helju Koger

    Index Scriptorium Estoniae

    Koger, Helju, 1943-

    2007-01-01

    VI kihelkonnapäevadest Juurus. Juuru Mihkli kirikus esines ansambel Resonabilis. Konverentsil räägiti Järlepa mõisast, Anu Allikvee pidas ettekande "August von Kotzebue elu nagu näitemäng" jm. Näitemängu "Pärmi Jaagu unenägu" nägi kohalike asjaarmastajate esituses

  12. Estimating the Reliability of a Test Containing Multiple Item Formats.

    Science.gov (United States)

    Qualls, Audrey L.

    1995-01-01

    Classically parallel, tau-equivalently parallel, and congenerically parallel models representing various degrees of part-test parallelism and their appropriateness for tests composed of multiple item formats are discussed. An appropriate reliability estimate for a test with multiple item formats is presented and illustrated. (SLD)

  13. The Use of Item Analysis for Improvement of Biochemical Teaching

    Science.gov (United States)

    Nagata, Ryoichi

    2004-01-01

    Item analysis was used to find out which biochemical explanations need to be improved in biochemical teaching, not which items are to be discarded, improved, or reusable in biochemical examinations. The analysis revealed the basic facts of which less able students had more misunderstanding than able students. Identifying these basic facts helps…

  14. Bayesian Item Selection in Constrained Adaptive Testing Using Shadow Tests

    Science.gov (United States)

    Veldkamp, Bernard P.

    2010-01-01

    Application of Bayesian item selection criteria in computerized adaptive testing might result in improvement of bias and MSE of the ability estimates. The question remains how to apply Bayesian item selection criteria in the context of constrained adaptive testing, where large numbers of specifications have to be taken into account in the item…

  15. Costs of Matrix Sampling of Test Items. ERIC Digest.

    Science.gov (United States)

    Childs, Ruth A.; Jaciw, Andrew P.

    Matrix sampling of test items, the division of a set of items into different versions of a test form, is used by several large-scale testing programs. This Digest discusses nine categories of costs associated with matrix sampling. These categories are: (1) development costs; (2) materials costs; (3) administration costs; (4) educational costs; (5)…

  16. 14 CFR Section 17 - Objective Classification-Extraordinary Items

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Objective Classification-Extraordinary Items Section 17 Section 17 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION... AIR CARRIERS Profit and Loss Classification Section 17 Objective Classification—Extraordinary Items...

  17. Automated addition of Chelex solution to tubes containing trace items

    DEFF Research Database (Denmark)

    Stangegaard, Michael; Hansen, Thomas Møller; Hansen, Anders Johannes;

    2011-01-01

    Extraction of DNA from trace items for forensic genetic DNA typing using a manual Chelex based extraction protocol requires addition of Chelex solution to sample tubes containing trace items. Automated of addition of Chelex solution may be hampered by high viscosity of the solution and fast...

  18. 17 CFR 229.1002 - (Item 1002) Subject company information.

    Science.gov (United States)

    2010-04-01

    ... ENERGY POLICY AND CONSERVATION ACT OF 1975-REGULATION S-K Mergers and Acquisitions (Regulation M-A) § 229.1002 (Item 1002) Subject company information. (a) Name and address. State the name of the subject... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false (Item 1002) Subject...

  19. Effects of Aging and IQ on Item and Associative Memory

    Science.gov (United States)

    Ratcliff, Roger; Thapar, Anjali; McKoon, Gail

    2011-01-01

    The effects of aging and IQ on performance were examined in 4 memory tasks: item recognition, associative recognition, cued recall, and free recall. For item and associative recognition, accuracy and the response time (RT) distributions for correct and error responses were explained by Ratcliff's (1978) diffusion model at the level of individual…

  20. Multidimensional Linking for Tests with Mixed Item Types

    Science.gov (United States)

    Yao, Lihua; Boughton, Keith

    2009-01-01

    Numerous assessments contain a mixture of multiple choice (MC) and constructed response (CR) item types and many have been found to measure more than one trait. Thus, there is a need for multidimensional dichotomous and polytomous item response theory (IRT) modeling solutions, including multidimensional linking software. For example,…