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Sample records for adaptive testing mat

  1. Implementation and Measurement Efficiency of Multidimensional Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Wang, Wen-Chung; Chen, Po-Hsi

    2004-01-01

    Multidimensional adaptive testing (MAT) procedures are proposed for the measurement of several latent traits by a single examination. Bayesian latent trait estimation and adaptive item selection are derived. Simulations were conducted to compare the measurement efficiency of MAT with those of unidimensional adaptive testing and random…

  2. Testlet-Based Multidimensional Adaptive Testing.

    PubMed

    Frey, Andreas; Seitz, Nicki-Nils; Brandt, Steffen

    2016-01-01

    Multidimensional adaptive testing (MAT) is a highly efficient method for the simultaneous measurement of several latent traits. Currently, no psychometrically sound approach is available for the use of MAT in testlet-based tests. Testlets are sets of items sharing a common stimulus such as a graph or a text. They are frequently used in large operational testing programs like TOEFL, PISA, PIRLS, or NAEP. To make MAT accessible for such testing programs, we present a novel combination of MAT with a multidimensional generalization of the random effects testlet model (MAT-MTIRT). MAT-MTIRT compared to non-adaptive testing is examined for several combinations of testlet effect variances (0.0, 0.5, 1.0, and 1.5) and testlet sizes (3, 6, and 9 items) with a simulation study considering three ability dimensions with simple loading structure. MAT-MTIRT outperformed non-adaptive testing regarding the measurement precision of the ability estimates. Further, the measurement precision decreased when testlet effect variances and testlet sizes increased. The suggested combination of the MTIRT model therefore provides a solution to the substantial problems of testlet-based tests while keeping the length of the test within an acceptable range.

  3. Testlet-Based Multidimensional Adaptive Testing

    PubMed Central

    Frey, Andreas; Seitz, Nicki-Nils; Brandt, Steffen

    2016-01-01

    Multidimensional adaptive testing (MAT) is a highly efficient method for the simultaneous measurement of several latent traits. Currently, no psychometrically sound approach is available for the use of MAT in testlet-based tests. Testlets are sets of items sharing a common stimulus such as a graph or a text. They are frequently used in large operational testing programs like TOEFL, PISA, PIRLS, or NAEP. To make MAT accessible for such testing programs, we present a novel combination of MAT with a multidimensional generalization of the random effects testlet model (MAT-MTIRT). MAT-MTIRT compared to non-adaptive testing is examined for several combinations of testlet effect variances (0.0, 0.5, 1.0, and 1.5) and testlet sizes (3, 6, and 9 items) with a simulation study considering three ability dimensions with simple loading structure. MAT-MTIRT outperformed non-adaptive testing regarding the measurement precision of the ability estimates. Further, the measurement precision decreased when testlet effect variances and testlet sizes increased. The suggested combination of the MTIRT model therefore provides a solution to the substantial problems of testlet-based tests while keeping the length of the test within an acceptable range. PMID:27917132

  4. Multidimensional Adaptive Testing in Educational and Psychological Measurement: Current State and Future Challenges

    ERIC Educational Resources Information Center

    Frey, Andreas; Seitz, Nicki-Nils

    2009-01-01

    The paper gives an overview of multidimensional adaptive testing (MAT) and evaluates its applicability in educational and psychological testing. The approach of Segall (1996) is described as a general framework for MAT. The main advantage of MAT is its capability to increase measurement efficiency. In simulation studies conceptualizing situations…

  5. Electrical resistance tests of glass mat type separators

    SciTech Connect

    Lind, A.L.

    1997-12-01

    Resistance measurement of glass mat separators for VRLA batteries is necessary for proper design selection. The equipment described makes sample comparison possible under compression in either flooded or starved condition. The Palico Instrument Labs method operates on the principle of measuring the change in resistance of test cell as electrolyte level is changed, first with and then without the separator sample. Since the separator can only be removed by removing the Model 903 Carrier and then reinserting after separator removal, stability to test readings and accurate measurement of electrolyte level are essential. Measurements are made with a reversing polarity DC current in all of the Palico resistance test equipment which closely match conditions found in the final battery.

  6. The Architecture of Iron Microbial Mats Reflects the Adaptation of Chemolithotrophic Iron Oxidation in Freshwater and Marine Environments

    PubMed Central

    Chan, Clara S.; McAllister, Sean M.; Leavitt, Anna H.; Glazer, Brian T.; Krepski, Sean T.; Emerson, David

    2016-01-01

    Microbes form mats with architectures that promote efficient metabolism within a particular physicochemical environment, thus studying mat structure helps us understand ecophysiology. Despite much research on chemolithotrophic Fe-oxidizing bacteria, Fe mat architecture has not been visualized because these delicate structures are easily disrupted. There are striking similarities between the biominerals that comprise freshwater and marine Fe mats, made by Beta- and Zetaproteobacteria, respectively. If these biominerals are assembled into mat structures with similar functional morphology, this would suggest that mat architecture is adapted to serve roles specific to Fe oxidation. To evaluate this, we combined light, confocal, and scanning electron microscopy of intact Fe microbial mats with experiments on sheath formation in culture, in order to understand mat developmental history and subsequently evaluate the connection between Fe oxidation and mat morphology. We sampled a freshwater sheath mat from Maine and marine stalk and sheath mats from Loihi Seamount hydrothermal vents, Hawaii. Mat morphology correlated to niche: stalks formed in steeper O2 gradients while sheaths were associated with low to undetectable O2 gradients. Fe-biomineralized filaments, twisted stalks or hollow sheaths, formed the highly porous framework of each mat. The mat-formers are keystone species, with nascent marine stalk-rich mats comprised of novel and uncommon Zetaproteobacteria. For all mats, filaments were locally highly parallel with similar morphologies, indicating that cells were synchronously tracking a chemical or physical cue. In the freshwater mat, cells inhabited sheath ends at the growing edge of the mat. Correspondingly, time lapse culture imaging showed that sheaths are made like stalks, with cells rapidly leaving behind an Fe oxide filament. The distinctive architecture common to all observed Fe mats appears to serve specific functions related to chemolithotrophic Fe

  7. The role of simulation in the development and flight test of the HiMAT vehicle

    NASA Technical Reports Server (NTRS)

    Evans, M. B.; Schilling, L. J.

    1984-01-01

    Real time simulations have been essential in the flight test program of the highly maneuverable aircraft technology (HiMAT) remotely piloted research vehicle at NASA Ames Research Center's Dryden Flight Research Facility. The HiMAT project makes extensive use of simulations in design, development, and qualification for flight, pilot training, and flight planning. Four distinct simulations, each with varying amounts of hardware in the loop, were developed for the HiMAT project. The use of simulations in detecting anomalous behavior of the flight software and hardware at the various stages of development, verification, and validation has been the key to flight qualification of the HiMAT vehicle.

  8. Induced mutations in circadian clock regulator Mat-a facilitated short-season adaptation and range extension in cultivated barley.

    PubMed

    Zakhrabekova, Shakhira; Gough, Simon P; Braumann, Ilka; Müller, André H; Lundqvist, Joakim; Ahmann, Katharina; Dockter, Christoph; Matyszczak, Izabela; Kurowska, Marzena; Druka, Arnis; Waugh, Robbie; Graner, Andreas; Stein, Nils; Steuernagel, Burkhard; Lundqvist, Udda; Hansson, Mats

    2012-03-13

    Time to flowering has an important impact on yield and has been a key trait in the domestication of crop plants and the spread of agriculture. In 1961, the cultivar Mari (mat-a.8) was the very first induced early barley (Hordeum vulgare L.) mutant to be released into commercial production. Mari extended the range of two-row spring barley cultivation as a result of its photoperiod insensitivity. Since its release, Mari or its derivatives have been used extensively across the world to facilitate short-season adaptation and further geographic range extension. By exploiting an extended historical collection of early-flowering mutants of barley, we identified Praematurum-a (Mat-a), the gene responsible for this key adaptive phenotype, as a homolog of the Arabidopsis thaliana circadian clock regulator Early Flowering 3 (Elf3). We characterized 87 induced mat-a mutant lines and identified >20 different mat-a alleles that had clear mutations leading to a defective putative ELF3 protein. Expression analysis of HvElf3 and Gigantea in mutant and wild-type plants demonstrated that mat-a mutations disturb the flowering pathway, leading to the early phenotype. Alleles of Mat-a therefore have important and demonstrated breeding value in barley but probably also in many other day-length-sensitive crop plants, where they may tune adaptation to different geographic regions and climatic conditions, a critical issue in times of global warming.

  9. Computer adaptive testing.

    PubMed

    Gershon, Richard C

    2005-01-01

    The creation of item response theory (IRT) and Rasch models, inexpensive accessibility to high speed desktop computers, and the growth of the Internet, has led to the creation and growth of computerized adaptive testing or CAT. This form of assessment is applicable for both high stakes tests such as certification or licensure exams, as well as health related quality of life surveys. This article discusses the historical background of CAT including its many advantages over conventional (typically paper and pencil) alternatives. The process of CAT is then described including descriptions of the specific differences of using CAT based upon 1-, 2- and 3-parameter IRT and various Rasch models. Numerous specific topics describing CAT in practice are described including: initial item selection, content balancing, test difficulty, test length and stopping rules. The article concludes with the author's reflections regarding the future of CAT.

  10. Highly Maneuverable Aircraft Technology (HiMAT) flight-flutter test program

    NASA Technical Reports Server (NTRS)

    Kehoe, M. W.

    1984-01-01

    The highly maneuverable aircraft technology (HiMAT) vehicle was evaluated in a joint NASA and Air Force flight test program. The HiMAT vehicle is a remotely piloted research vehicle. Its design incorporates the use of advanced composite materials in the wings, and canards for aeroelastic tailoring. A flight-flutter test program was conducted to clear a sufficient flight envelope to allow for performance, stability and control, and loads testing. Testing was accomplished with and without flight control-surface dampers. Flutter clearance of the vehicle indicated satisfactory damping and damping trends for the structural modes of the HiMAT vehicle. The data presented include frequency and damping plotted as a function of Mach number.

  11. Leak test adapter for containers

    DOEpatents

    Hallett, Brian H.; Hartley, Michael S.

    1996-01-01

    An adapter is provided for facilitating the charging of containers and leak testing penetration areas. The adapter comprises an adapter body and stem which are secured to the container's penetration areas. The container is then pressurized with a tracer gas. Manipulating the adapter stem installs a penetration plug allowing the adapter to be removed and the penetration to be leak tested with a mass spectrometer. Additionally, a method is provided for using the adapter.

  12. Photosynthetic action spectra and adaptation to spectral light distribution in a benthic cyanobacterial mat

    NASA Technical Reports Server (NTRS)

    Jorgensen, B. B.; Cohen, Y.; Des Marais, D. J.

    1987-01-01

    We studied adaptation to spectral light distribution in undisturbed benthic communities of cyanobacterial mats growing in hypersaline ponds at Guerrero Negro, Baja California, Mexico. Microscale measurements of oxygen photosynthesis and action spectra were performed with microelectrodes; spectral radiance was measured with fiber-optic microprobes. The spatial resolution of all measurements was 0.1 mm, and the spectral resolution was 10 to 15 nm. Light attenuation spectra showed absorption predominantly by chlorophyll a (Chl a) (430 and 670 nm), phycocyanin (620 nm), and carotenoids (440 to 500 nm). Blue light (450 nm) was attenuated 10-fold more strongly than red light (600 nm). The action spectra of the surface film of diatoms accordingly showed activity over the whole spectrum, with maxima for Chl a and carotenoids. The underlying dense Microcoleus population showed almost exclusively activity dependent upon light harvesting by phycobilins at 550 to 660 nm. Maximum activity was at 580 and 650 nm, indicating absorption by phycoerythrin and phycocyanin as well as by allophycocyanin. Very little Chl a-dependent activity could be detected in the cyanobacterial action spectrum, even with additional 600-nm light to excite photosystem II. The depth distribution of photosynthesis showed detectable activity down to a depth of 0.8 to 2.5 mm, where the downwelling radiant flux at 600 nm was reduced to 0.2 to 0.6% of the surface flux.

  13. Flight control systems development and flight test experience with the HiMAT research vehicles

    NASA Technical Reports Server (NTRS)

    Kempel, Robert W.; Earls, Michael R.

    1988-01-01

    Two highly maneuverable aircraft technology (HiMAT) remotely piloted vehicles were flown a total of 26 flights. These subscale vehicles were of advanced aerodynamic configuration with advanced technology concepts such as composite and metallic structures, digital integrated propulsion control, and ground (primary) and airborne (backup) relaxed static stability, digital fly-by-wire control systems. Extensive systems development, checkout, and flight qualification were required to conduct the flight test program. The design maneuver goal was to achieve a sustained 8-g turn at Mach 0.9 at an altitude of 25,000 feet. This goal was achieved, along with the acquisition of high-quality flight data at subsonic and supersonic Mach numbers. Control systems were modified in a variety of ways using the flight-determined aerodynamic characteristics. The HiMAT program was successfully completed with approximately 11 hours of total flight time.

  14. HiMAT flight program: Test results and program assessment overview

    NASA Technical Reports Server (NTRS)

    Deets, Dwain A.; Deangelis, V. Michael; Lux, David P.

    1986-01-01

    The Highly Manueverable Aircraft Technology (HiMAT) program consisted of design, fabrication of two subscale remotely piloted research vehicles (RPRVs), and flight test. This technical memorandum describes the vehicles and test approach. An overview of the flight test results and comparisons with the design predictions are presented. These comparisons are made on a single-discipline basis, so that aerodynamics, structures, flight controls, and propulsion controls are examined one by one. The interactions between the disciplines are then examined, with the conclusions that the integration of the various technologies contributed to total vehicle performance gains. An assessment is made of the subscale RPRV approach from the standpoint of research data quality and quantity, unmanned effects as compared with manned vehicles, complexity, and cost. It is concluded that the RPRV technique, as adopted in this program, resulted in a more complex and costly vehicle than expected but is reasonable when compared with alternate ways of obtaining comparable results.

  15. Psychometrics behind Computerized Adaptive Testing.

    PubMed

    Chang, Hua-Hua

    2015-03-01

    The paper provides a survey of 18 years' progress that my colleagues, students (both former and current) and I made in a prominent research area in Psychometrics-Computerized Adaptive Testing (CAT). We start with a historical review of the establishment of a large sample foundation for CAT. It is worth noting that the asymptotic results were derived under the framework of Martingale Theory, a very theoretical perspective of Probability Theory, which may seem unrelated to educational and psychological testing. In addition, we address a number of issues that emerged from large scale implementation and show that how theoretical works can be helpful to solve the problems. Finally, we propose that CAT technology can be very useful to support individualized instruction on a mass scale. We show that even paper and pencil based tests can be made adaptive to support classroom teaching.

  16. Mission Adaptive Wing test program

    NASA Technical Reports Server (NTRS)

    Birk, Frank T.; Smith, Rogers E.

    1986-01-01

    With the completion of the F-111 test-bed Mission Adaptive Wing (MAW) test program's manual flight control system, emphasis has been shifted to flight testing of MAW automatic control modes. These encompass (1) cruise camber control, (2) maneuver camber control, (3) maneuver load control, and (4) maneuver enhancement and load alleviation control. The aircraft is currently cleared to a 2.5-g maneuvering limit due to generally higher variable-incidence wing pivot loads than had been anticipated, especially at the higher wing-camber settings. Buffet is noted to be somewhat higher than expected at the higher camber settings.

  17. Diagnostic Classification Models and Multidimensional Adaptive Testing: A Commentary on Rupp and Templin

    ERIC Educational Resources Information Center

    Frey, Andreas; Carstensen, Claus H.

    2009-01-01

    On a general level, the objective of diagnostic classifications models (DCMs) lies in a classification of individuals regarding multiple latent skills. In this article, the authors show that this objective can be achieved by multidimensional adaptive testing (MAT) as well. The authors discuss whether or not the restricted applicability of DCMs can…

  18. Testing the utility of matK and ITS DNA regions for discrimination of Allium species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Molecular phylogenetic analysis of the genus Allium L. has been mainly based on the nucleotide sequences of ITS region. In 2009 matK and rbcL were accepted as a two-locus DNA barcode to classify plant species by the Consortium for the Barcode of Life (CBOL) Plant Working Group. MatK region has been ...

  19. Distribution of cold adaptation proteins in microbial mats in Lake Joyce, Antarctica: Analysis of metagenomic data by using two bioinformatics tools.

    PubMed

    Koo, Hyunmin; Hakim, Joseph A; Fisher, Phillip R E; Grueneberg, Alexander; Andersen, Dale T; Bej, Asim K

    2016-01-01

    In this study, we report the distribution and abundance of cold-adaptation proteins in microbial mat communities in the perennially ice-covered Lake Joyce, located in the McMurdo Dry Valleys, Antarctica. We have used MG-RAST and R code bioinformatics tools on Illumina HiSeq2000 shotgun metagenomic data and compared the filtering efficacy of these two methods on cold-adaptation proteins. Overall, the abundance of cold-shock DEAD-box protein A (CSDA), antifreeze proteins (AFPs), fatty acid desaturase (FAD), trehalose synthase (TS), and cold-shock family of proteins (CSPs) were present in all mat samples at high, moderate, or low levels, whereas the ice nucleation protein (INP) was present only in the ice and bulbous mat samples at insignificant levels. Considering the near homogeneous temperature profile of Lake Joyce (0.08-0.29 °C), the distribution and abundance of these proteins across various mat samples predictively correlated with known functional attributes necessary for microbial communities to thrive in this ecosystem. The comparison of the MG-RAST and the R code methods showed dissimilar occurrences of the cold-adaptation protein sequences, though with insignificant ANOSIM (R = 0.357; p-value = 0.012), ADONIS (R(2) = 0.274; p-value = 0.03) and STAMP (p-values = 0.521-0.984) statistical analyses. Furthermore, filtering targeted sequences using the R code accounted for taxonomic groups by avoiding sequence redundancies, whereas the MG-RAST provided total counts resulting in a higher sequence output. The results from this study revealed for the first time the distribution of cold-adaptation proteins in six different types of microbial mats in Lake Joyce, while suggesting a simpler and more manageable user-defined method of R code, as compared to a web-based MG-RAST pipeline.

  20. The Effects of Test Difficulty Manipulation in Computerized Adaptive Testing and Self-Adapted Testing.

    ERIC Educational Resources Information Center

    Ponsoda, Vicente; Olea, Julio; Rodriguez, Maria Soledad; Revuelta, Javier

    1999-01-01

    Compared easy and difficult versions of self-adapted tests (SAT) and computerized adapted tests. No significant differences were found among the tests for estimated ability or posttest state anxiety in studies with 187 Spanish high school students, although other significant differences were found. Discusses implications for interpreting test…

  1. Applicable Adaptive Testing Models for School Teachers.

    ERIC Educational Resources Information Center

    Wang, Albert Chang-hwa; Chuang, Chi-lin

    2002-01-01

    Describes a study conducted in Taipei (Taiwan) that investigated the attitudinal effects of SPRT (Sequential Probability Ratio Test) adaptive testing environment on junior high school students. Discusses test anxiety; student preferences; test adaptability; acceptance of test results; number of items answered; and computer experience. (Author/LRW)

  2. Adaptive Testing without a Computer.

    DTIC Science & Technology

    1981-03-01

    AO-A09? 353 AErSIARCH APPLICATIONS INC ROCKVILZI 14 P /s 5/9 ADAPTIVE TESTING WITHOUT A COMPUTER,(U) MAR 81 0 FRIEDMAN. A STEINBRG. N J RE I33615-?797...I -, IhI, III h II I I ,.-, r 11 % lll,.l ,n h . ,’l , ,, *i I.T I .- I,’ I I I ,I,, ’, I .I ,. I- Rofk %i h’ I l ,r I N ,,II I _ 2 1 W - P II11_...a., ,ol ) I ,I’l t \\I. I T1Hl.11’r . A a. SLCUi~~ AS AT ,N IF T HIS P AGE .’%h,, 0i.1. 1’ ,lli EPORT DOCUMENTATION PAGE IIEI-op INST!WAI(T)s O U R

  3. Rotationally Adaptive Flight Test Surface

    NASA Technical Reports Server (NTRS)

    Barrett, Ron

    1999-01-01

    Research on a new design of flutter exciter vane using adaptive materials was conducted. This novel design is based on all-moving aerodynamic surface technology and consists of a structurally stiff main spar, a series of piezoelectric actuator elements and an aerodynamic shell which is pivoted around the main spar. The work was built upon the current missile-type all-moving surface designs and change them so they are better suited for flutter excitation through the transonic flight regime. The first portion of research will be centered on aerodynamic and structural modeling of the system. USAF DatCom and vortex lattice codes was used to capture the fundamental aerodynamics of the vane. Finite element codes and laminated plate theory and virtual work analyses will be used to structurally model the aerodynamic vane and wing tip. Following the basic modeling, a flutter test vane was designed. Each component within the structure was designed to meet the design loads. After the design loads are met, then the deflections will be maximized and the internal structure will be laid out. In addition to the structure, a basic electrical control network will be designed which will be capable of driving a scaled exciter vane. The third and final stage of main investigation involved the fabrication of a 1/4 scale vane. This scaled vane was used to verify kinematics and structural mechanics theories on all-moving actuation. Following assembly, a series of bench tests was conducted to determine frequency response, electrical characteristics, mechanical and kinematic properties. Test results indicate peak-to-peak deflections of 1.1 deg with a corner frequency of just over 130 Hz.

  4. Nondestructive Magnetic Adaptive Testing of nuclear reactor pressure vessel steel degradation

    NASA Astrophysics Data System (ADS)

    Tomáš, I.; Vértesy, G.; Gillemot, F.; Székely, R.

    2013-01-01

    Inspection of neutron-irradiation-generated degradation of nuclear reactor pressure vessel steel (RPVS) is a very important task. In ferromagnetic materials, such as RPVS, the structural degradation is connected with a change of their magnetic properties. In this work, applicability of a novel magnetic nondestructive method (Magnetic Adaptive Testing, MAT), based on systematic measurement and evaluation of minor magnetic hysteresis loops, is shown for inspection of neutron irradiation embrittlement in RPVS. Three series of samples, made of JRQ, 15CH2MFA and 10ChMFT type steels were measured by MAT. The samples were irradiated by E > 1 MeV energy neutrons with total neutron fluence of 1.58 × 1019-11.9 × 1019 n/cm2. Regular correlation was found between the optimally chosen MAT degradation functions and the neutron fluence in all three types of the materials. Shift of the ductile-brittle transition temperature, ΔDBTT, independently determined as a function of the neutron fluence for the 15CH2MFA material, was also evaluated. A sensitive, linear correlation was found between the ΔDBTT and values of the relevant MAT degradation function. Based on these results, MAT is shown to be a promising (at least) complimentary tool of the destructive tests within the surveillance programs, which are presently used for inspection of neutron-irradiation-generated embrittlement of RPVS.

  5. Computerized Adaptive Mastery Tests as Expert Systems.

    ERIC Educational Resources Information Center

    Frick, Theodore W.

    1992-01-01

    Discussion of expert systems and computerized adaptive tests describes two versions of EXSPRT, a new approach that combines uncertain inference in expert systems with sequential probability ratio test (SPRT) stopping rules. Results of two studies comparing EXSPRT to adaptive mastery testing based on item response theory and SPRT approaches are…

  6. Flow-induced Development of Unicellular Cyanobacterial Mats

    NASA Astrophysics Data System (ADS)

    Gong, J.; Tice, M. M.

    2011-12-01

    Microbial mats/biofilms are abundant microbial growth structures throughout the history of life on Earth. Understanding the mechanisms for their morphogenesis and interactions with physical sedimentary forces are important topics that allow deeper understanding of related records. When subjected to hydrodynamic influences, mats are known to vary in morphology and structure in response to fluid shear, yet mechanistically, the underlying cellular architecture due to interactions with flow remain unexplained. Moreover, mats are found to emerge larger scale roughness elements and modified cohesive strength growing under flow. It is a mystery how and why these mat-community-level features are linked in association with modified boundary layers at the mats surface. We examined unicellular cyanobacterium Synechocystis sp. PCC 6803 in a circular flow bioreactor designed to maintain a fixed set of hydrodynamic conditions. The use of monoculture strains and unidirectional currents, while not replicating natural mat systems (almost certainly multi-species and often multi-directional currents under complex wind or tidal wave actions), helps to simplify these systems and allows for specific testing of hypotheses regarding how mats evolve distinctive morphologies induced by flow. The unique design of the reactor also makes measurements such as critical erosional shear stress of the mats possible, in addition to microscopic, macroscopic imaging and weeks of continuous mats growth monitoring. We report the finding that linear chains, filament-like cell groups were present from unicellular cyanobacterial mats growing under flow (~1-5 cm/s) and these structures are organized within ~1-3mm size streamers and ~0.5-1mm size nodular macrostructures. Ultra-small, sub-micron thick EPS strings are observed under TEM and are likely the cohesive architectural elements in mats across different fluid regimes. Mat cohesion generally grows with and adapts to increasing flow shear stress within

  7. Flexilevel Adaptive Testing Paradigm: Hierarchical Concept Structures.

    DTIC Science & Technology

    1977-07-01

    items . In reference to the psychometric outcomes, Table 3 presents the mean item difficulties by subtest plus a Kuder - Richardson reliability index. A...leas~: 50percent of the subject population , an adaptive Kuder - Richardson index was calculated . This was found to be r = . 701 for Block II test and r...whole correlations between adaptive test and total test scores (r ’s = .95). Descriptive test indices and test reliabilities were also essentially

  8. Test Anxiety, Computer-Adaptive Testing and the Common Core

    ERIC Educational Resources Information Center

    Colwell, Nicole Makas

    2013-01-01

    This paper highlights the current findings and issues regarding the role of computer-adaptive testing in test anxiety. The computer-adaptive test (CAT) proposed by one of the Common Core consortia brings these issues to the forefront. Research has long indicated that test anxiety impairs student performance. More recent research indicates that…

  9. Flight Test Approach to Adaptive Control Research

    NASA Technical Reports Server (NTRS)

    Pavlock, Kate Maureen; Less, James L.; Larson, David Nils

    2011-01-01

    The National Aeronautics and Space Administration s Dryden Flight Research Center completed flight testing of adaptive controls research on a full-scale F-18 testbed. The validation of adaptive controls has the potential to enhance safety in the presence of adverse conditions such as structural damage or control surface failures. This paper describes the research interface architecture, risk mitigations, flight test approach and lessons learned of adaptive controls research.

  10. Hypothetical Use of Multidimensional Adaptive Testing for the Assessment of Student Achievement in the Programme for International Student Assessment

    ERIC Educational Resources Information Center

    Frey, Andreas; Seitz, Nicki-Nils

    2011-01-01

    The usefulness of multidimensional adaptive testing (MAT) for the assessment of student literacy in the Programme for International Student Assessment (PISA) was examined within a real data simulation study. The responses of N = 14,624 students who participated in the PISA assessments of the years 2000, 2003, and 2006 in Germany were used to…

  11. A Model for Optimal Constrained Adaptive Testing.

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Reese, Lynda M.

    1998-01-01

    Proposes a model for constrained computerized adaptive testing in which the information in the test at the trait level (theta) estimate is maximized subject to the number of possible constraints on the content of the test. Test assembly relies on a linear-programming approach. Illustrates the approach through simulation with items from the Law…

  12. The Stratified Adaptive Computerized Ability Test.

    ERIC Educational Resources Information Center

    Weiss, David J.

    This report describes the stratified adaptive (stradaptive) test as a strategy for tailoring an ability test to individual differences in testee ability; administration of the test is controlled by a time-shared computer system. The rationale of this method is described as it derives from Binet's strategy of ability test administration and…

  13. Evaluating Content Alignment in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Wise, Steven L.; Kingsbury, G. Gage; Webb, Norman L.

    2015-01-01

    The alignment between a test and the content domain it measures represents key evidence for the validation of test score inferences. Although procedures have been developed for evaluating the content alignment of linear tests, these procedures are not readily applicable to computerized adaptive tests (CATs), which require large item pools and do…

  14. Test Target for Adaptive Optics.

    DTIC Science & Technology

    adaptive optics comprising, in the preferred embodiment, a plurality of nine adjacent, stacked, and aligned rows of a multiplicity of alternate opaque sections and transparent sections in a repeating bar pattern, with all sections being positioned on a flat transparent medium (such as film or glass), and with each opaque section being an opaque bar and with each transparent section being a transparent bar. Each row has a different spatial frequency than any other of the nine rows, with the spatial frequency of any one row being of a different multiple of the row having the

  15. Bayesian Item Selection in Constrained Adaptive Testing Using Shadow Tests

    ERIC Educational Resources Information Center

    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…

  16. Graphical Models and Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Almond, Russell G.; Mislevy, Robert J.

    1999-01-01

    Considers computerized adaptive testing from the perspective of graphical modeling (GM). GM provides methods for making inferences about multifaceted skills and knowledge and for extracting data from complex performances. Provides examples from language-proficiency assessment. (SLD)

  17. Adaptive structures - Test hardware and experimental results

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Fanson, James L.; Chen, Gun-Shing; Kuo, Chin-Po

    1990-01-01

    The facilities and procedures used at JPL to test adaptive structures such as the large deployable reflector (LDR) are described and preliminary results are reported. The applications of adaptive structures in future NASA missions are outlined, and the techniques which are employed to modify damping, stiffness, and isolation characteristics, as well as geometric changes, are listed. The development of adaptive structures is shown to be effective as a result of new actuators and sensors, and examples are listed for categories such as fiber optics, shape-memory materials, piezoelectrics, and electrorheological fluids. Some ground test results are described for laboratory truss structures and truss test beds, which are shown to be efficient and easy to assemble in space. Adaptive structures are shown to be important for precision space structures such as the LDR, and can alleviate ground test requirements.

  18. Structural analysis of closure cap barriers: A pre-test study for the Bentonite Mat Demonstration Project

    SciTech Connect

    Gong, Chung

    1993-10-01

    According to the EPA-recommended closure cap design a waste site can either be covered with a single layer cap made of 36 inches of compacted soil (clay) or with a multilayer cap consisting of an upper vegetative layer underlain by a drainage layer over a low permeability layer. The Bentonite Mat Demonstration Project (BMDP) is a field demonstration study to determine the construction/installation requirements, permeability, and subsidence performance characteristics of a composite barrier. The composite barrier will consist of on-site sandy-clay blanketed by a bentonite mat and a flexible High Density Polyethylene (HDPE) liner (also called flexible membrane liner). Construction of one control test pad and three bentonite test pads are planned. The control test pad will be used to establish baseline data. Underneath the composite clay cap is a four-foot loose sand layer in which cavities will be created by evacuation of sand. The present work provides a mathematical model for the BMDP. The mathematical model will be used to simulate the mechanical and structural responses of the composite clay cap during the testing processes. Based upon engineering experience and technical references, a set of nominal soil parameters have been selected. Currently, detailed soil test data and cavity configuration data are not available to validate the mathematical model. Since the configuration of the cavities created in the testing process is irregular and unpredictable, two extreme configurations are considered in this mathematical model, viz., the circular cavity and the infinitely long trench in the sand underneath the cap. This approach will provide bounds for the testing results.

  19. Evaluation Parameters for Computer-Adaptive Testing

    ERIC Educational Resources Information Center

    Georgiadou, Elisabeth; Triantafillou, Evangelos; Economides, Anastasios A.

    2006-01-01

    With the proliferation of computers in test delivery today, adaptive testing has become quite popular, especially when examinees must be classified into two categories (passfail, master nonmaster). Several well-established organisations have provided standards and guidelines for the design and evaluation of educational and psychological testing.…

  20. Computer Adaptive Testing: A New Era.

    ERIC Educational Resources Information Center

    Smittle, Pat

    1993-01-01

    Describes a study to determine whether traditional paper-and-pencil tests or new computer-adaptive tests were better suited for assessing entering students at Santa Fe Community College, Florida. Focuses on teachers' attitudes toward computerized placement tests (CPTs), relationships between CPT scores and course grades, predictive ability of CPT…

  1. Strategies for Computerized Adaptive Grading Testing.

    ERIC Educational Resources Information Center

    Xiao, Beiling

    1999-01-01

    Evaluated three strategies for assigning examinees to grading categories in computerized adaptive testing. The expected a posteriori-based method had more correct classifications in the middle range of grade levels and more errors for the extremes than the golden section search grading test and the Z-score grading test. (SLD)

  2. Dichotomous Search Strategies for Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Xiao, Beiling

    Dichotomous search strategies (DSSs) for computerized adaptive testing are similar to golden section search strategies (GSSSs). Each middle point of successive search regions is a testing point. After each item is administered, the subject's obtained score is compared with the expected score at successive testing points. If the subject's obtained…

  3. An Introduction to the Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Tian, Jian-quan; Miao, Dan-min; Zhu, Xia; Gong, Jing-jing

    2007-01-01

    Computerized adaptive testing (CAT) has unsurpassable advantages over traditional testing. It has become the mainstream in large scale examinations in modern society. This paper gives a brief introduction to CAT including differences between traditional testing and CAT, the principles of CAT, psychometric theory and computer algorithms of CAT, the…

  4. Computerized Adaptive Testing in Reading.

    ERIC Educational Resources Information Center

    Smittle, Pat

    1991-01-01

    Discusses the use of computerized placement testing at Santa Fe Community College to enable students needing only a short review of reading skills to exit early from a College Preparatory Reading Class (CPRC). Describes CPRC placement, structure, curriculum, and exit criteria; the Early Exit Reading Project; and project results. (DMM)

  5. Robustness of Adaptive Testing to Multidimensionality.

    ERIC Educational Resources Information Center

    Weiss, David J.; Suhadolnik, Debra

    The present monte carlo simulation study was designed to examine the effects of multidimensionality during the administration of computerized adaptive testing (CAT). It was assumed that multidimensionality existed in the individuals to whom test items were being administered, i.e., that the correct or incorrect responses given by an individual…

  6. Individual Differences in Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Kim, JinGyu

    Research on the major computerized adaptive testing (CAT) strategies is reviewed, and some findings are reported that examine effects of examinee demographic and psychological characteristics on CAT strategies. In fixed branching strategies, all examinees respond to a common routing test, the score of which is used to assign examinees to a…

  7. A Guide to Computer Adaptive Testing Systems

    ERIC Educational Resources Information Center

    Davey, Tim

    2011-01-01

    Some brand names are used generically to describe an entire class of products that perform the same function. "Kleenex," "Xerox," "Thermos," and "Band-Aid" are good examples. The term "computerized adaptive testing" (CAT) is similar in that it is often applied uniformly across a diverse family of testing methods. Although the various members of…

  8. Computerized Adaptive Testing with Item Cloning.

    ERIC Educational Resources Information Center

    Glas, Cees A. W.; van der Linden, Wim J.

    2003-01-01

    Developed a multilevel item response (IRT) model that allows for differences between the distributions of item parameters of families of item clones. Results from simulation studies based on an item pool from the Law School Admission Test illustrate the accuracy of the item pool calibration and adaptive testing procedures based on the model. (SLD)

  9. Conical isogrid adapter structural test results

    NASA Technical Reports Server (NTRS)

    Dyer, J. E.; Slysh, P.

    1974-01-01

    The structural characteristics of isogrid composite structures are discussed. To demonstrate the feasibility of applying isogrid to conical structures, a full scale flanged isogrid conical adapter similar to the configuration of the D-1 Centaur equipment module was constructed. The adapter was tested to evaluate the response of the conical isogrid structure to various combinations of bending and axial compression loading. The analysis techniques for predicting conical isogrid structural capability are examined.

  10. Adaptive interpretation of gas well deliverability tests

    NASA Astrophysics Data System (ADS)

    Sergeev, V. L.; Thac Hoai Phuong, Nguyen; Strelnikova, A. B.

    2016-09-01

    The paper considers topical issues of improving accuracy of data obtained from gas well deliverability tests, decreasing the number of test stages and well test time, and reducing gas emissions. The aim of the research is to develop the method of adaptive interpretation of gas well deliverability tests with resulting IPR curve conducted in gas wells with steady-state filtration, which allows obtaining and taking into account additional a priori data on the formation pressure and flow coefficients, setting the number of test stages adequate for efficient well testing and reducing test time. The present research is based on the previous theoretical and practical findings in the spheres of gas well deliverability tests, systems analysis, system identification, function optimization and linear algebra. To test the method, the authors used the field data of deliverability tests run in the Urengoy gas and condensate field, Tyumen Oblast. The authors suggest the method of adaptive interpretation of gas well deliverability tests with resulting IPR curve, which is based on the law for gas filtration with variables dependent on the number of test stage and account of additional a priori data. The suggested method allows defining the estimates of the formation pressure and flow coefficients, optimal in terms of preassigned measures of quality, and setting the adequate number of test stages in the course of well testing. The case study of IPR curve data processing has indicated that adaptive interpretation provides more accurate estimates on the formation pressure and flow coefficients, as well as reduces the number of test stages.

  11. Development and Psychometric Evaluation of the Hansen Research Services Matrix Adaptive Test: A Measure of Nonverbal IQ.

    PubMed

    Hansen, John A

    2016-10-13

    Assessment of individuals on the autism spectrum often includes a measure of nonverbal IQ. One such measure is the Raven's Standard Progressive Matrices (RSPM). For large research studies with participants distributed nationally it is desirable for assessments to be available online. Because time is a premium, it is ideal that the measure produces accurate scores quickly. The Hansen Research Services Matrix Adaptive Test (HRS-MAT) addresses these needs and with similar psychometric properties of the RSPM. Scores based on the HRS-MAT correlated at r = .81 with those of the RSPM. In adult-child pairs, HRS-MAT scores correlated at approximately r = .50. Details from respondents in a national sample and psychometric properties including reliability and validity are discussed.

  12. A Consideration for Variable Length Adaptive Tests.

    ERIC Educational Resources Information Center

    Wingersky, Marilyn S.

    In a variable-length adaptive test with a stopping rule that relied on the asymptotic standard error of measurement of the examinee's estimated true score, M. S. Stocking (1987) discovered that it was sufficient to know the examinee's true score and the number of items administered to predict with some accuracy whether an examinee's true score was…

  13. i RadMat: A thermo-mechanical testing system for in situ high-energy X-ray characterization of radioactive specimens

    DOE PAGES

    Zhang, Xuan; Xu, Chi; Wang, Leyun; ...

    2017-01-27

    Here, we present an in situ Radiated Materials (iRadMat) experimental module designed to interface with a servo-hydraulic load frame for X-ray measurements at beamline 1-ID at the Advanced Photon Source. This new capability allows in situ studies of radioactive specimens subject to thermo-mechanical loading using a suite of high-energy X-ray scattering and imaging techniques. The iRadMat is a radiation-shielded vacuum heating system with the sample rotation-under-load capability. We describe the design features and performances of the iRadMat and present a dataset from a 300 °C uniaxial tensile test of a neutron-irradiated pure Fe specimen to demonstrate its capabilities.

  14. iRadMat: A thermo-mechanical testing system for in situ high-energy X-ray characterization of radioactive specimens

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan; Xu, Chi; Wang, Leyun; Chen, Yiren; Li, Meimei; Almer, Jonathan D.; Benda, Erika; Kenesei, Peter; Mashayekhi, Ali; Park, Jun-Sang; Westferro, Frank J.

    2017-01-01

    We present an in situ Radiated Materials (iRadMat) experimental module designed to interface with a servo-hydraulic load frame for X-ray measurements at beamline 1-ID at the Advanced Photon Source. This new capability allows in situ studies of radioactive specimens subject to thermo-mechanical loading using a suite of high-energy X-ray scattering and imaging techniques. The iRadMat is a radiation-shielded vacuum heating system with the sample rotation-under-load capability. We describe the design features and performances of the iRadMat and present a dataset from a 300 °C uniaxial tensile test of a neutron-irradiated pure Fe specimen to demonstrate its capabilities.

  15. HiRadMat at CERN SPS - A test facility with high intensity beam pulses to material samples

    SciTech Connect

    Charitonidis, N.; Fabich, A.; Efthymiopoulos, I.

    2015-07-01

    HiRadMat (High Irradiation to Materials) is a facility at CERN designed to provide high-intensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies (e.g. vacuum windows, shock tests on high power targets, collimators) can be tested. The beam parameters (SPS 440 GeV protons with a pulse energy of up to 3.4 MJ, or alternatively lead/argon ions at the proton equivalent energy) can be tuned to match the needs of each experiment. It is a test area designed to perform single pulse experiments to evaluate the effect of high-intensity pulsed beams on materials in a dedicated environment, excluding long-time irradiation studies. The facility is designed for a 10{sup 16} maximum number of protons per year, in order to limit the activation to acceptable levels for human intervention. This paper will demonstrate the possibilities for research using this facility and showing examples of upcoming experiments scheduled in the beam period 2014/2015. (authors)

  16. Spatial and spatio-temporal clustering of overall and serovar-specific Leptospira microscopic agglutination test (MAT) seropositivity among dogs in the United States from 2000 through 2007.

    PubMed

    Gautam, Raju; Guptill, Lynn F; Wu, Ching Ching; Potter, Adam; Moore, George E

    2010-08-01

    Leptospirosis is a re-emerging disease of dogs in the United States (U.S.). This paper reports the findings of a retrospective study conducted to determine if seroreactivity to Leptospira microscopic agglutination test (MAT) among dogs in the U.S. clustered in space and time. The study utilized canine sera submitted to a commercial laboratory for leptospiral MAT from January 2000 through December 2007. There were 31,869 serum samples submitted by veterinarians from 3156 zip code locations across the U.S. Results of MAT were considered positive at titers of > or = 1:1600. Spatial and spatial-temporal scan statistics were used to identify statistically significant clusters of seroreactivity to Leptospira (overall and individual serovars) using recorded test request dates and locations of the centroid of the zip code reported for each serum sample. There were 2469 positive MAT results with a titer > or = 1:1600 to at least one of seven Leptospira serovars. Two relevant spatial clusters of 26.3 and 246.5 km radius were identified (P=0.001). The primary cluster was located in the northeastern part of Illinois including Chicago and surrounding areas (232 [14.4%] of 1612 MAT positive; RR=1.95). The secondary cluster covered the central part of Texas (292 [12.62%] of 2314 MAT positive; RR=1.71). Eight space-time clusters of overall MAT positivity were identified (29-335 km radius; P=0.001-0.048 and RR=3.98-24.69) that covered different geographic locations for different time points. Spatial and space-time clusters for individual serovars were also identified for six serovars: eight each of Grippotyphosa and Pomona, seven of Bratislava, five of Autumnalis, and three each of Icterohaemorrhagiae and Canicola. In conclusion Leptospira seropositivity in dogs tended to have distinctive clusters in space and space-time. Most of the space-time clusters of overall Leptospira MAT seropositivity were associated with cluster events for individual serovars. Further investigation is

  17. The ESO Adaptive Optics Facility under Test

    NASA Astrophysics Data System (ADS)

    Arsenault, Robin; Madec, Pierre-Yves; Paufique, Jerome; La Penna, Paolo; Stroebele, Stefan; Vernet, Elise; Pirard, Jean-François; Hackenberg, Wolfgang; Kuntschner, Harald; Kolb, Johann; Muller, Nicolas; Le Louarn, Miska; Amico, Paola; Hubin, Norbert; Lizon, Jean-Louis; Ridings, Rob; Abad, Jose; Fischer, Gert; Heinz, Volker; Kiekebusch, Mario; Argomedo, Javier; Conzelmann, Ralf; Tordo, Sebastien; Donaldson, Rob; Soenke, Christian; Duhoux, Philippe; Fedrigo, Enrico; Delabre, Bernard; Jost, Andrea; Duchateau, Michel; Downing, Mark; Moreno, Javier; Manescau, Antonio; Bonaccini Calia, Domenico; Quattri, Marco; Dupuy, Christophe; Guidolin, Ivan; Comin, Mauro; Guzman, Ronald; Buzzoni, Bernard; Quentin, Jutta; Lewis, Steffan; Jolley, Paul; Kraus, Max; Pfrommer, Thomas; Garcia-Rissmann, Aurea; Biasi, Roberto; Gallieni, Daniele; Stuik, Remko

    2013-12-01

    The Adaptive Optics Facility project has received most of its subsystems in Garching and the ESO Integration Hall has become the central operation location for the next phase of the project. The main test bench ASSIST and the 2nd Generation M2-Unit (hosting the Deformable Secondary Mirror) have been granted acceptance late 2012. The DSM will now undergo a series of tests on ASSIST to qualify its optical performance which launches the System Test Phase of the AOF. The tests will validate the AO modules operation with the DSM: first the GRAAL adaptive optics module for Hawk-I in natural guide star AO mode on-axis and then its Ground Layer AO mode. This will be followed by the GALACSI (for MUSE) Wide-Field-Mode (GLAO) and then the more challenging Narrow-Field-Mode (LTAO). We will report on the status of the subsystems at the time of the conference but also on the performance of the delivered ASSIST test bench, the DSM and the 20 Watt Sodium fiber Laser pre-production unit which has validated all specifications before final manufacturing of the serial units. We will also present some considerations and tools to ensure an efficient operation of the Facility in Paranal.

  18. MAT Program Test Summary Report. Biconic Body with Slice/Flap

    DTIC Science & Technology

    1982-01-01

    8217• " Stokes (PNS) codes , and other detailed flow field codesJ 4kTests_ were conducted at the von Karman Facility (VKF) of the Arnold Enginec. g velopment...as well as examples of data retrieved for code comparison purposes. ’I.- - 1 3z , f.. . o -. 2. UNCLASSIFIED SE-CURITY CLASSIVICATION nr Twi; oA’-VCflM...46 10 Photograph of the Probe Housing Assembly with the Probe Assembly Attached 49 11 Photograph of the Probe Assembly 50 12 Close-up Photograph of

  19. An experiment to test advanced materials impacted by intense proton pulses at CERN HiRadMat facility

    NASA Astrophysics Data System (ADS)

    Bertarelli, A.; Berthome, E.; Boccone, V.; Carra, F.; Cerutti, F.; Charitonidis, N.; Charrondiere, C.; Dallocchio, A.; Fernandez Carmona, P.; Francon, P.; Gentini, L.; Guinchard, M.; Mariani, N.; Masi, A.; Marques dos Santos, S. D.; Moyret, P.; Peroni, L.; Redaelli, S.; Scapin, M.

    2013-08-01

    Predicting the consequences of highly energetic particle beams impacting protection devices as collimators or high power target stations is a fundamental issue in the design of state-of-the-art facilities for high-energy particle physics. These complex dynamic phenomena can be successfully simulated resorting to highly non-linear numerical tools (Hydrocodes). In order to produce accurate results, however, these codes require reliable material constitutive models that, at the extreme conditions induced by a destructive beam impact, are scarce and often inaccurate. In order to derive or validate such models a comprehensive, first-of-its-kind experiment has been recently carried out at CERN HiRadMat facility: performed tests entailed the controlled impact of intense and energetic proton pulses on a number of specimens made of six different materials. Experimental data were acquired relying on embedded instrumentation (strain gauges, temperature probes and vacuum sensors) and on remote-acquisition devices (laser Doppler vibrometer and high-speed camera). The method presented in this paper, combining experimental measurements with numerical simulations, may find applications to assess materials under very high strain rates and temperatures in domains well beyond particle physics (severe accidents in fusion and fission nuclear facilities, space debris impacts, fast and intense loadings on materials and structures etc.).

  20. Adaptive testing for psychological assessment: how many items are enough to run an adaptive testing algorithm?

    PubMed

    Wagner-Menghin, Michaela M; Masters, Geoff N

    2013-01-01

    Although the principles of adaptive testing were established in the psychometric literature many years ago (e.g., Weiss, 1977), and practice of adaptive testing is established in educational assessment, it not yet widespread in psychological assessment. One obstacle to adaptive psychological testing is a lack of clarity about the necessary number of items to run an adaptive algorithm. The study explores the relationship between item bank size, test length and measurement precision. Simulated adaptive test runs (allowing a maximum of 30 items per person) out of an item bank with 10 items per ability level (covering .5 logits, 150 items total) yield a standard error of measurement (SEM) of .47 (.39) after an average of 20 (29) items for 85-93% (64-82%) of the simulated rectangular sample. Expanding the bank to 20 items per level (300 items total) did not improve the algorithm's performance significantly. With a small item bank (5 items per ability level, 75 items total) it is possible to reach the same SEM as with a conventional test, but with fewer items or a better SEM with the same number of items.

  1. Adaptive random testing with combinatorial input domain.

    PubMed

    Huang, Rubing; Chen, Jinfu; Lu, Yansheng

    2014-01-01

    Random testing (RT) is a fundamental testing technique to assess software reliability, by simply selecting test cases in a random manner from the whole input domain. As an enhancement of RT, adaptive random testing (ART) has better failure-detection capability and has been widely applied in different scenarios, such as numerical programs, some object-oriented programs, and mobile applications. However, not much work has been done on the effectiveness of ART for the programs with combinatorial input domain (i.e., the set of categorical data). To extend the ideas to the testing for combinatorial input domain, we have adopted different similarity measures that are widely used for categorical data in data mining and have proposed two similarity measures based on interaction coverage. Then, we propose a new version named ART-CID as an extension of ART in combinatorial input domain, which selects an element from categorical data as the next test case such that it has the lowest similarity against already generated test cases. Experimental results show that ART-CID generally performs better than RT, with respect to different evaluation metrics.

  2. Effects of mat characteristics on plantar pressure patterns and perceived mat properties during landing in gymnastics.

    PubMed

    Pérez-Soriano, Pedro; Llana-Belloch, Salvador; Morey-Klapsing, Gaspar; Perez-Turpin, Jose Antonio; Cortell-Tormo, Juan Manuel; van den Tillaar, Roland

    2010-11-01

    Shock absorption and stability during landings is provided by both, gymnast ability and mat properties. The aims of this study were to determine the influence of different mat constructions on their energy absorption and stability capabilities, and to analyse how these properties affect gymnast's plantar pressures as well as subjective mat perception during landing. Six mats were tested using a standard mechanical drop test. In addition, plantar pressures and subjective perception during landing were obtained from 15 expert gymnasts. The different mats influenced plantar pressures and gymnasts' subjective perception during landing of gymnasts. Significant correlations between plantar pressures at the medial metatarsal and lateral metatarsal zones of the gymnasts' feet with the different shock absorption characteristics of the mats were found. However, subjective perception tests were not able to discriminate mat functionality between the six mats as no significant correlations between the mechanical mat properties with the subjective perception of these properties were found. This study demonstrated that plantar pressures are a useful tool for discriminating different landing mats. Using similar approaches, ideally including kinematics as well, could help us in our understanding about the influences of different mats upon gymnast-mat interaction.

  3. "catR": An R Package for Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Magis, David; Raiche, Gilles

    2011-01-01

    Computerized adaptive testing (CAT) is an active current research field in psychometrics and educational measurement. However, there is very little software available to handle such adaptive tasks. The R package "catR" was developed to perform adaptive testing with as much flexibility as possible, in an attempt to provide a developmental and…

  4. Case Studies in Computer Adaptive Test Design through Simulation.

    ERIC Educational Resources Information Center

    Eignor, Daniel R.; And Others

    The extensive computer simulation work done in developing the computer adaptive versions of the Graduate Record Examinations (GRE) Board General Test and the College Board Admissions Testing Program (ATP) Scholastic Aptitude Test (SAT) is described in this report. Both the GRE General and SAT computer adaptive tests (CATs), which are fixed length…

  5. The molecular dimension of microbial species: 2. Synechococcus strains representative of putative ecotypes inhabiting different depths in the Mushroom Spring microbial mat exhibit different adaptive and acclimative responses to light

    PubMed Central

    Nowack, Shane; Olsen, Millie T.; Schaible, George A.; Becraft, Eric D.; Shen, Gaozhong; Klapper, Isaac; Bryant, Donald A.; Ward, David M.

    2015-01-01

    Closely related strains of thermophilic Synechococcus were cultivated from the microbial mats found in the effluent channels of Mushroom Spring, Yellowstone National Park (YNP). These strains have identical or nearly identical 16S rRNA sequences but are representative of separate, predicted putative ecotype (PE) populations, which were identified by using the more highly resolving psaA locus and which predominate at different vertical positions within the 1-mm-thick upper-green layer of the mat. Pyrosequencing confirmed that each strain contained a single, predominant psaA genotype. Strains differed in growth rate as a function of irradiance. A strain with a psaA genotype corresponding to a predicted PE that predominates near the mat surface grew fastest at high irradiances, whereas strains with psaA genotypes representative of predominant subsurface populations grew faster at low irradiance and exhibited greater sensitivity to abrupt shifts to high light. The high-light-adapted and low-light-adapted strains also exhibited differences in pigment content and the composition of the photosynthetic apparatus (photosystem ratio) when grown under different light intensities. Cells representative of the different strains had similar morphologies under low-light conditions, but under high-light conditions, cells of low-light-adapted strains became elongated and formed short chains of cells. Collectively, the results presented here are consistent with the hypothesis that closely related, but distinct, ecological species of Synechococcus occupy different light niches in the Mushroom Spring microbial mat and acclimate differently to changing light environments. PMID:26175719

  6. Adaptive interferometric null testing for unknown freeform optics metrology.

    PubMed

    Huang, Lei; Choi, Heejoo; Zhao, Wenchuan; Graves, Logan R; Kim, Dae Wook

    2016-12-01

    We report an adaptive interferometric null testing method for overcoming the dynamic range limitations of conventional null testing approaches during unknown freeform optics metrology or optics manufacturing processes that require not-yet-completed surface measurements to guide the next fabrication process. In the presented adaptive method, a deformable mirror functions as an adaptable null component for an unknown optical surface. The optimal deformable mirror's shape is determined by the stochastic parallel gradient descent algorithm and controlled by a deflectometry system. An adaptive interferometric null testing setup was constructed, and its metrology data successfully demonstrated superb adaptive capability in measuring an unknown surface.

  7. MATS: a Bayesian framework for flexible detection of differential alternative splicing from RNA-Seq data

    PubMed Central

    Shen, Shihao; Park, Juw Won; Huang, Jian; Dittmar, Kimberly A.; Lu, Zhi-xiang; Zhou, Qing; Carstens, Russ P.; Xing, Yi

    2012-01-01

    Ultra-deep RNA sequencing has become a powerful approach for genome-wide analysis of pre-mRNA alternative splicing. We develop MATS (multivariate analysis of transcript splicing), a Bayesian statistical framework for flexible hypothesis testing of differential alternative splicing patterns on RNA-Seq data. MATS uses a multivariate uniform prior to model the between-sample correlation in exon splicing patterns, and a Markov chain Monte Carlo (MCMC) method coupled with a simulation-based adaptive sampling procedure to calculate the P-value and false discovery rate (FDR) of differential alternative splicing. Importantly, the MATS approach is applicable to almost any type of null hypotheses of interest, providing the flexibility to identify differential alternative splicing events that match a given user-defined pattern. We evaluated the performance of MATS using simulated and real RNA-Seq data sets. In the RNA-Seq analysis of alternative splicing events regulated by the epithelial-specific splicing factor ESRP1, we obtained a high RT–PCR validation rate of 86% for differential exon skipping events with a MATS FDR of <10%. Additionally, over the full list of RT–PCR tested exons, the MATS FDR estimates matched well with the experimental validation rate. Our results demonstrate that MATS is an effective and flexible approach for detecting differential alternative splicing from RNA-Seq data. PMID:22266656

  8. A "Rearrangement Procedure" for Scoring Adaptive Tests with Review Options

    ERIC Educational Resources Information Center

    Papanastasiou, Elena C.; Reckase, Mark D.

    2007-01-01

    Because of the increased popularity of computerized adaptive testing (CAT), many admissions tests, as well as certification and licensure examinations, have been transformed from their paper-and-pencil versions to computerized adaptive versions. A major difference between paper-and-pencil tests and CAT from an examinee's point of view is that in…

  9. Assessing Existing Item Bank Depth for Computer Adaptive Testing.

    ERIC Educational Resources Information Center

    Bergstrom, Betty A.; Stahl, John A.

    This paper reports a method for assessing the adequacy of existing item banks for computer adaptive testing. The method takes into account content specifications, test length, and stopping rules, and can be used to determine if an existing item bank is adequate to administer a computer adaptive test efficiently across differing levels of examinee…

  10. Multidimensional Adaptive Testing with Optimal Design Criteria for Item Selection

    ERIC Educational Resources Information Center

    Mulder, Joris; van der Linden, Wim J.

    2009-01-01

    Several criteria from the optimal design literature are examined for use with item selection in multidimensional adaptive testing. In particular, it is examined what criteria are appropriate for adaptive testing in which all abilities are intentional, some should be considered as a nuisance, or the interest is in the testing of a composite of the…

  11. The Development and Evaluation of a Computerized Adaptive Testing System.

    ERIC Educational Resources Information Center

    de-la-Torre, Roberto; Vispoel, Walter P.

    The development and preliminary evaluation of the Computerized Adaptive Testing System (CATSYS), a new testing package for IBM-compatible microcomputers, are described. CATSYS can be used to administer and score operational adaptive tests or to conduct on-line computer simulation studies. The package incorporates several innovative features,…

  12. Mat2exo

    SciTech Connect

    2012-09-11

    MAT2EXO is a program which translates mesh data from Matlab mat-file format to Exodus II format. This tool is the inverse of the commonly used tool exo2mat which translates Exodus II data to the Matlab mat-file format. These tools provide a means for preprocessing an Exodus II model file or postprocessing an Exodus II results file using Matlab

  13. A Method for Severely Constrained Item Selection in Adaptive Testing.

    ERIC Educational Resources Information Center

    Stocking, Martha L.; Swanson, Len

    1993-01-01

    A method is presented for incorporating a large number of constraints on adaptive item selection in the construction of computerized adaptive tests. The method, which emulates practices of expert test specialists, is illustrated for verbal and quantitative measures. Its foundation is application of a weighted deviations model and algorithm. (SLD)

  14. Evaluating the Content Validity of Multistage-Adaptive Tests

    ERIC Educational Resources Information Center

    Crotts, Katrina; Sireci, Stephen G.; Zenisky, April

    2012-01-01

    Validity evidence based on test content is important for educational tests to demonstrate the degree to which they fulfill their purposes. Most content validity studies involve subject matter experts (SMEs) who rate items that comprise a test form. In computerized-adaptive testing, examinees take different sets of items and test "forms"…

  15. Turkish Adaptation of Test of Pretended Play

    ERIC Educational Resources Information Center

    Aydin, Aydan

    2012-01-01

    The objective of present research is to conduct validity and reliability analysis of the verbal section of Test of Pretended Play that will measure pretended play behaviors of pre-school age children (3-6 years of age). Test of Pretended Play was first developed by Vicky Lewis and Jill Boucher in 1997. This test aimed to measure pretended play…

  16. An Automatic Online Calibration Design in Adaptive Testing

    ERIC Educational Resources Information Center

    Makransky, Guido; Glas, Cees A. W.

    2010-01-01

    An accurately calibrated item bank is essential for a valid computerized adaptive test. However, in some settings, such as occupational testing, there is limited access to test takers for calibration. As a result of the limited access to possible test takers, collecting data to accurately calibrate an item bank in an occupational setting is…

  17. Modern Sequential Analysis and Its Applications to Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Bartroff, Jay; Finkelman, Matthew; Lai, Tze Leung

    2008-01-01

    After a brief review of recent advances in sequential analysis involving sequential generalized likelihood ratio tests, we discuss their use in psychometric testing and extend the asymptotic optimality theory of these sequential tests to the case of sequentially generated experiments, of particular interest in computerized adaptive testing. We…

  18. A Sharing Item Response Theory Model for Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Segall, Daniel O.

    2004-01-01

    A new sharing item response theory (SIRT) model is presented that explicitly models the effects of sharing item content between informants and test takers. This model is used to construct adaptive item selection and scoring rules that provide increased precision and reduced score gains in instances where sharing occurs. The adaptive item selection…

  19. A computerized adaptive test for enterprising personality assessment in youth.

    PubMed

    Pedrosa, Ignacio; Suárez-Álvarez, Javier; García-Cueto, Eduardo; Muñiz, José

    2016-11-01

    Backgound : Assessing specific personality traits has shown better predictive power of enterprising personality than have broad personality traits. Hitherto, there have been no instruments that evaluate the combination of specific personality traits of enterprising personality in an adaptive format. So, the aim was to develop a Computerized Adaptive Test (CAT) to assess enterprising personality in young people.

  20. Application of Sequential Interval Estimation to Adaptive Mastery Testing

    ERIC Educational Resources Information Center

    Chang, Yuan-chin Ivan

    2005-01-01

    In this paper, we apply sequential one-sided confidence interval estimation procedures with beta-protection to adaptive mastery testing. The procedures of fixed-width and fixed proportional accuracy confidence interval estimation can be viewed as extensions of one-sided confidence interval procedures. It can be shown that the adaptive mastery…

  1. In-situ Curing Strain Monitoring of a Flat Plate Residual Stress Specimen Using a Chopped Stand Mat Glass/Epoxy Composite as Test Material

    NASA Astrophysics Data System (ADS)

    Jakobsen, J.; Skordos, A.; James, S.; Correia, R. G.; Jensen, M.

    2015-12-01

    The curing stresses in a newly proposed bi-axial residual stress testing configuration are studied using a chopped strand mat glass/epoxy specimen. In-situ monitoring of the curing is conducted using dielectric and fibre Bragg grating sensors. It is confirmed that a bi-axial residual stress state can be introduced in the specimens during curing and a quantification of its magnitude is presented. An alternative decomposition method used for converting the dielectric signal into a material state variable is proposed and good agreement with models found in the literature is obtained. From the cure cycles chosen it is suggested that any stress build up in the un-vitrified state is relaxed immediately and only stress build up in the vitrified state contributes to the residual stress state in the specimen.

  2. Evaluation of Degradation of Ceramic Fiber Mat by Acoustic Emission

    SciTech Connect

    Ito, Kaita; Enoki, Manabu; Takahashi, Hidetomo

    2005-04-09

    Alumina-silica fiber mat is widely used as thermal insulator because of its good stability under high temperature environment. However, this material degrades gradually during long-term use under pressure and elevated temperature. In this study, cyclic compression tests of the mat were conducted and monitored acoustic emission (AE) of the mat both at room temperature and elevated temperature. The degradation of mat was evaluated by AE parameters.

  3. Evaluation of Degradation of Ceramic Fiber Mat by Acoustic Emission

    NASA Astrophysics Data System (ADS)

    Ito, Kaita; Enoki, Manabu; Takahashi, Hidetomo

    2005-04-01

    Alumina-silica fiber mat is widely used as thermal insulator because of its good stability under high temperature environment. However, this material degrades gradually during long-term use under pressure and elevated temperature. In this study, cyclic compression tests of the mat were conducted and monitored acoustic emission (AE) of the mat both at room temperature and elevated temperature. The degradation of mat was evaluated by AE parameters.

  4. Online Calibration via Variable Length Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Chang, Yuan-chin Ivan; Lu, Hung-Yi

    2010-01-01

    Item calibration is an essential issue in modern item response theory based psychological or educational testing. Due to the popularity of computerized adaptive testing, methods to efficiently calibrate new items have become more important than that in the time when paper and pencil test administration is the norm. There are many calibration…

  5. Simple and Effective Algorithms: Computer-Adaptive Testing.

    ERIC Educational Resources Information Center

    Linacre, John Michael

    Computer-adaptive testing (CAT) allows improved security, greater scoring accuracy, shorter testing periods, quicker availability of results, and reduced guessing and other undesirable test behavior. Simple approaches can be applied by the classroom teacher, or other content specialist, who possesses simple computer equipment and elementary…

  6. Balancing Flexible Constraints and Measurement Precision in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Moyer, Eric L.; Galindo, Jennifer L.; Dodd, Barbara G.

    2012-01-01

    Managing test specifications--both multiple nonstatistical constraints and flexibly defined constraints--has become an important part of designing item selection procedures for computerized adaptive tests (CATs) in achievement testing. This study compared the effectiveness of three procedures: constrained CAT, flexible modified constrained CAT,…

  7. A Computer-Adaptive Vocabulary Test

    ERIC Educational Resources Information Center

    Molina, Maria Teresa Lopez-Mezquita

    2009-01-01

    Lexical competence is considered to be an essential step in the development and consolidation of a student's linguistic ability, and thus the reliable assessment of such competence turns out to be a fundamental aspect in this process. The design and construction of vocabulary tests has become an area of special interest, as it may provide teachers…

  8. Adaptation of a-Stratified Method in Variable Length Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Wen, Jian-Bing; Chang, Hua-Hua; Hau, Kit-Tai

    Test security has often been a problem in computerized adaptive testing (CAT) because the traditional wisdom of item selection overly exposes high discrimination items. The a-stratified (STR) design advocated by H. Chang and his collaborators, which uses items of less discrimination in earlier stages of testing, has been shown to be very…

  9. HiMAT in flight

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The HiMAT (Highly Maneuverable Aircraft Technology) subscale research vehicle, seen here during a research flight, was flown by the NASA Dryden Flight Research Center, Edwards, California, from mid 1979 to January 1983. The aircraft demonstrated advanced fighter technologies that have been used in the development of many modern high performance military aircraft. Two vehicles were used in the research program conducted jointly by NASA and the Air Force Flight Dynamics Laboratory, Wright-Patterson AFB, Ohio. The two vehicles, flown a total of 26 times, provided data on the use of composites, aeroelastic tailoring, close-coupled canards and winglets. They investigated the interaction of these then-new technologies upon each other. About one-half the size of a standard manned fighter and powered by a small jet engine, the HiMAT vehicles were launched from NASA's B-52 carrier aircraft at an altitude of about 45,000 feet. They were flown remotely by a NASA research pilot from a ground station with the aid of a television camera mounted in the HiMAT cockpits. Technologies tested on the HiMAT vehicles appearing later on other aircraft include the extensive use of composites common now on military and commercial aircraft; rear-mounted wing and forward canard configuration used very successfully on the X-29 research aircraft flown at Dryden; and winglets, now used on many private and commercial aircraft to lessen wingtip drag and enhance fuel savings.

  10. [Peritoneal equilibration test: Conventional versus adapted. Preliminary study].

    PubMed

    Zaloszyc, Ariane; Schmitt, Claus Peter; Schaefer, Betti; Doutey, Armelle; Terzic, Joëlle; Menouer, Soraya; Higel, Laetitia; Fischbach, Michel

    2017-02-01

    Conventional automated peritoneal dialysis (APD) is prescribed as a repetition of cycles with the same dwell time and the same fill volume. Water and sodium balance remains a common problem among patients on peritoneal dialysis. More recently, adapted automated peritoneal dialysis was described, as a combination of short dwells with a low volume, in order to enhance ultrafiltration, followed by long dwells with a large fill volume to favor solute removal. We performed a preliminary crossover study on 4 patients. The total amount of dialysate was the same, i.e. 2L/m(2) as well as the total duration of the test, i.e. 150 minutes. The conventional test was made with two identical cycles, each cycle had a fill volume of 1L/m(2) and a duration of 75 minutes, while the adapted test was performed with one short cycle, i.e. 30 minutes with a low fill volume, i.e. 0.6L/m(2), followed by a long cycle, i.e. 120 minutes, with a large fill volume, i.e. 1.4L/m(2). Sodium extraction was improved by 29.3mmol/m(2) (169%) in the adapted test in comparison to the conventional test. Ultrafiltration was enhanced by 159mL/m(2) (128%) in the adapted test compared to the conventional one. Glucose absorption was decreased by 35% in the adapted test in comparison to the conventional test and osmotic conductance was also improved. In conclusion, adapted dialysis may allow for a better volume and sodium balance, since we observed an improvement in sodium extraction and ultrafiltration. This pre-study authorizes an improvement of the European Pediatric Study's protocol on Adapted APD, already started and which will continue in the next months.

  11. [European Portuguese EARS test battery adaptation].

    PubMed

    Alves, Marisa; Ramos, Daniela; Oliveira, Graça; Alves, Helena; Anderson, Ilona; Magalhães, Isabel; Martins, Jorge H; Simões, Margarida; Ferreira, Raquel; Fonseca, Rita; Andrade, Susana; Silva, Luís; Ribeiro, Carlos; Ferreira, Pedro Lopes

    2014-01-01

    Introdução: A utilização de instrumentos de avaliação em saúde adequados é fundamental na gestão da prestação de cuidados. A escassez, em Portugal, de instrumentos específicos para a avaliação do desempenho de crianças utilizadoras de implantes cocleares motivou o trabalho de tradução e de adaptação da bateria de testes EARS (Evaluation of Auditory Responses to Speech) para o português europeu. Esta bateria de testes é hoje um dos instrumentos mais comummente utilizados por equipas de (re)habilitação de crianças surdas com implantes cocleares em todo o mundo. O objetivo a atingir com a validação do EARS foi fornecer às equipas de (re)habilitação um instrumento que permita: (i) monitorizar a evolução individual da reabilitação; (ii) gerir um programa de (re)habilitação de acordo com resultados objetivos, comparáveis entre diferentes equipas de (re)habilitação; (iii) obter dados comparáveis comequipas internacionais; e (iv) melhorar a adesão e a motivação da família e restantes profissionais no ambulatório.Material e Métodos: No processo de tradução e de adaptação da bateria de testes, os procedimentos adotados foram os seguintes: (i) tradução da versão inglesa para português europeu por um tradutor profissional; (ii) revisão dessa tradução realizada por um painel de especialistas constituído por otorrinolaringologistas, terapeutas da fala e técnicos de audiologia; (iii) adaptação dos estímulos de teste pela equipa de terapeutas da fala; e (iv) nova revisão por parte do painel de especialistas.Resultados: São apresentados, para cada um dos instrumentos que compõem a bateria EARS, as adaptações introduzidas, conciliando as características e os objetivos originais dos instrumentos com as particularidades linguísticas e culturais da população portuguesa.Discussão: São discutidas as dificuldades encontradas durante o processo de tradução e de adaptação e as soluções adotadas. São feitas

  12. An adaptive interferometer for optical testing .

    NASA Astrophysics Data System (ADS)

    Pariani, G.; Colella, L.; Bertarelli, C.; Aliverti, M.; Riva, M.; Bianco, A.

    Interferometry is a well-established technique to test optical elements. However, its use is challenging in the case of free-form and aspheric elements, due to the lack of the reference optics. The proposed idea concerns the development of a versatile interferometer, where its reference arm is equipped with a reprogrammable Computer Generated Hologram. This principle takes advantage from our study on photochromic materials for optical applications, which shows a strong and reversible modulation of transparency in the visible region. The encoding of the desired hologram can be done off-line, or directly into the interferometer, and different patterns may be realized sequentially after the erasing of the previous hologram. We report on the present state of the research and on the future perspectives. skip=5pt

  13. Deriving Stopping Rules for Multidimensional Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Wang, Chun; Chang, Hua-Hua; Boughton, Keith A.

    2013-01-01

    Multidimensional computerized adaptive testing (MCAT) is able to provide a vector of ability estimates for each examinee, which could be used to provide a more informative profile of an examinee's performance. The current literature on MCAT focuses on the fixed-length tests, which can generate less accurate results for those examinees whose…

  14. Computerized Adaptive Testing: From Inquiry to Operation [Book Review].

    ERIC Educational Resources Information Center

    Gierl, Mark J.

    1998-01-01

    This book documents the research, development, and implementation efforts that allowed the U.S. Department of Defense to initiate the Computerized Adaptive Testing Armed Services Vocational Aptitude Battery Program for enlistment testing. Traces the history of this program over 30 years. (SLD)

  15. Proceedings of the 1977 Computerized Adaptive Testing Conference.

    ERIC Educational Resources Information Center

    Weiss, David J., Ed.

    The 27 papers in this collection (26 of which were presented at the conference) are organized according to the eight topical sessions: (1) Improving Ability Measurement Using Different Item Formats, (2) Alternative Models for Adaptive Testing, (3) Psychological and Subgroup Effects, (4) Performance Testing by Interactive Simulation, (5)…

  16. Multidimensional Computerized Adaptive Testing for Indonesia Junior High School Biology

    ERIC Educational Resources Information Center

    Kuo, Bor-Chen; Daud, Muslem; Yang, Chih-Wei

    2015-01-01

    This paper describes a curriculum-based multidimensional computerized adaptive test that was developed for Indonesia junior high school Biology. In adherence to the Indonesian curriculum of different Biology dimensions, 300 items was constructed, and then tested to 2238 students. A multidimensional random coefficients multinomial logit model was…

  17. Some Properties of a Bayesian Adaptive Ability Testing Strategy.

    ERIC Educational Resources Information Center

    McBride, James R.; Weiss, David J.

    Four monte carlo simulation studies of Owen's Bayesian sequential procedure for adaptive mental testing were conducted. Whereas previous simulation studies of this procedure have concentrated on evaluating it in terms of the correlation of its test scores with simulated ability in a normal population, these four studies explored a number of…

  18. An Adaptive Testing System for Supporting Versatile Educational Assessment

    ERIC Educational Resources Information Center

    Huang, Yueh-Min; Lin, Yen-Ting; Cheng, Shu-Chen

    2009-01-01

    With the rapid growth of computer and mobile technology, it is a challenge to integrate computer based test (CBT) with mobile learning (m-learning) especially for formative assessment and self-assessment. In terms of self-assessment, computer adaptive test (CAT) is a proper way to enable students to evaluate themselves. In CAT, students are…

  19. A Conditional Exposure Control Method for Multidimensional Adaptive Testing

    ERIC Educational Resources Information Center

    Finkelman, Matthew; Nering, Michael L.; Roussos, Louis A.

    2009-01-01

    In computerized adaptive testing (CAT), ensuring the security of test items is a crucial practical consideration. A common approach to reducing item theft is to define maximum item exposure rates, i.e., to limit the proportion of examinees to whom a given item can be administered. Numerous methods for controlling exposure rates have been proposed…

  20. Optimal Design of Item Banks for Computerized Adaptive Tests.

    ERIC Educational Resources Information Center

    Stocking, Martha L.; Swanson, Len

    1998-01-01

    Applied optimal design methods to the item-bank design of adaptive testing for continuous testing situations using a version of the weighted-deviations model (M. Stocking and L. Swanson, 1993) in a simulation. Independent and overlapping item banks used items more efficiently than did a large item bank. (SLD)

  1. Mutual Information Item Selection in Adaptive Classification Testing

    ERIC Educational Resources Information Center

    Weissman, Alexander

    2007-01-01

    A general approach for item selection in adaptive multiple-category classification tests is provided. The approach uses mutual information (MI), a special case of the Kullback-Leibler distance, or relative entropy. MI works efficiently with the sequential probability ratio test and alleviates the difficulties encountered with using other local-…

  2. Computerized Adaptive Testing through the World Wide Web.

    ERIC Educational Resources Information Center

    Shermis, Mark D.; Mzumara, Howard; Brown, Mike; Lillig, Clo

    An important problem facing institutions of higher education is the number of students reporting that they are not adequately prepared for the difficulty of college-level courses. To meet this problem, a computerized adaptive testing package was developed that permitted remote placement testing of high school students via the World Wide Web. The…

  3. Microcomputer Network for Computerized Adaptive Testing (CAT): Program Listing.

    ERIC Educational Resources Information Center

    Quan, Baldwin; And Others

    This program listing is a supplement to the Microcomputer Network for Computerized Adaptive Testing (CAT). The driver textfile program allows access to major subprograms of the CAT project. The test administration textfile program gives examinees a prescribed set of subtests. The parameter management textfile program establishes a file containing…

  4. A Procedure for Empirical Initialization of Adaptive Testing Algorithms.

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    In constrained adaptive testing, the numbers of constraints needed to control the content of the tests can easily run into the hundreds. Proper initialization of the algorithm becomes a requirement because the presence of large numbers of constraints slows down the convergence of the ability estimator. In this paper, an empirical initialization of…

  5. When Cognitive Diagnosis Meets Computerized Adaptive Testing: CD-CAT

    ERIC Educational Resources Information Center

    Cheng, Ying

    2009-01-01

    Computerized adaptive testing (CAT) is a mode of testing which enables more efficient and accurate recovery of one or more latent traits. Traditionally, CAT is built upon Item Response Theory (IRT) models that assume unidimensionality. However, the problem of how to build CAT upon latent class models (LCM) has not been investigated until recently,…

  6. Assessing the Efficiency of Item Selection in Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Weissman, Alexander

    This study investigated the efficiency of item selection in a computerized adaptive test (CAT), where efficiency was defined in terms of the accumulated test information at an examinee's true ability level. A simulation methodology compared the efficiency of 2 item selection procedures with 5 ability estimation procedures for CATs of 5, 10, 15,…

  7. Pressure Sensitive Mats as Safety Devices in Danger Zones.

    PubMed

    Dąbrowski, Stanisław; Brański, Zygfryd

    1998-01-01

    Developing prototypes of pressure sensitive mats and testing their practical application were the aims of this study. Two contact plate mats were designed and constructed: rubber-rubber (R) and metal-metal (M). A recipe for rubber mixes and the production technology were prepared. Two laboratory test stands for measuring the actuating force, response time, static pressure resistance, and the durability of the mats were constructed. Computer software was written to control the operation of those test stands. Methods of testing pressure sensitive mats were based on PrDIN 31 006 (Deutsches Institut fur Normung [DIN], 1990) and EN 1760-1 (Comite Europeen de Normalisation [CEN], 1997). Both prototypes of contact plate mats were tested under laboratory and industrial conditions. The test results proved that the design was correct, the setup requirements were fulfilled, and the mats were efficient and reliable in the industrial environment.

  8. Polytomous Adaptive Classification Testing: Effects of Item Pool Size, Test Termination Criterion, and Number of Cutscores

    ERIC Educational Resources Information Center

    Gnambs, Timo; Batinic, Bernad

    2011-01-01

    Computer-adaptive classification tests focus on classifying respondents in different proficiency groups (e.g., for pass/fail decisions). To date, adaptive classification testing has been dominated by research on dichotomous response formats and classifications in two groups. This article extends this line of research to polytomous classification…

  9. ProMat

    SciTech Connect

    2008-06-12

    ProMAT is a software tool for statistically analyzing data from enzyme-linked immunosorbent assay microarray experiments. The software estimates standard curves, sample protein concentrations and their uncertainties for multiple assays. ProMAT generates a set of comprehensive figures for assessing results and diagnosing process quality. The tool is available for Windows or Mac, and is distributed as open-source Java and R code

  10. Testing the adaptive radiation hypothesis for the lemurs of Madagascar

    PubMed Central

    2017-01-01

    Lemurs, the diverse, endemic primates of Madagascar, are thought to represent a classic example of adaptive radiation. Based on the most complete phylogeny of living and extinct lemurs yet assembled, I tested predictions of adaptive radiation theory by estimating rates of speciation, extinction and adaptive phenotypic evolution. As predicted, lemur speciation rate exceeded that of their sister clade by nearly twofold, indicating the diversification dynamics of lemurs and mainland relatives may have been decoupled. Lemur diversification rates did not decline over time, however, as predicted by adaptive radiation theory. Optimal body masses diverged among dietary and activity pattern niches as lineages diversified into unique multidimensional ecospace. Based on these results, lemurs only partially fulfil the predictions of adaptive radiation theory, with phenotypic evolution corresponding to an ‘early burst’ of adaptive differentiation. The results must be interpreted with caution, however, because over the long evolutionary history of lemurs (approx. 50 million years), the ‘early burst’ signal of adaptive radiation may have been eroded by extinction. PMID:28280597

  11. Use of adaptive walls in 2D tests

    NASA Technical Reports Server (NTRS)

    Archambaud, J. P.; Chevallier, J. P.

    1984-01-01

    A new method for computing the wall effects gives precise answers to some questions arising in adaptive wall concept applications: length of adapted regions, fairings with up and downstream regions, residual misadjustments effects, reference conditions. The acceleration of the iterative process convergence and the development of an efficient technology used in CERT T2 wind tunnels give in a single run the required test conditions. Samples taken from CAST 7 tests demonstrate the efficiency of the whole process to obtain significant results with considerations of tridimensional case extension.

  12. HIDEC F-15 adaptive engine control system flight test results

    NASA Technical Reports Server (NTRS)

    Smolka, James W.

    1987-01-01

    NASA-Ames' Highly Integrated Digital Electronic Control (HIDEC) flight test program aims to develop fully integrated airframe, propulsion, and flight control systems. The HIDEC F-15 adaptive engine control system flight test program has demonstrated that significant performance improvements are obtainable through the retention of stall-free engine operation throughout the aircraft flight and maneuver envelopes. The greatest thrust increase was projected for the medium-to-high altitude flight regime at subsonic speed which is of such importance to air combat. Adaptive engine control systems such as the HIDEC F-15's can be used to upgrade the performance of existing aircraft without resort to expensive reengining programs.

  13. Optimal Bayesian Adaptive Design for Test-Item Calibration.

    PubMed

    van der Linden, Wim J; Ren, Hao

    2015-06-01

    An optimal adaptive design for test-item calibration based on Bayesian optimality criteria is presented. The design adapts the choice of field-test items to the examinees taking an operational adaptive test using both the information in the posterior distributions of their ability parameters and the current posterior distributions of the field-test parameters. Different criteria of optimality based on the two types of posterior distributions are possible. The design can be implemented using an MCMC scheme with alternating stages of sampling from the posterior distributions of the test takers' ability parameters and the parameters of the field-test items while reusing samples from earlier posterior distributions of the other parameters. Results from a simulation study demonstrated the feasibility of the proposed MCMC implementation for operational item calibration. A comparison of performances for different optimality criteria showed faster calibration of substantial numbers of items for the criterion of D-optimality relative to A-optimality, a special case of c-optimality, and random assignment of items to the test takers.

  14. Brazilian Adaptation of the Woodcock-Johnson III Cognitive Tests

    ERIC Educational Resources Information Center

    Wechsler, Solange Muglia; Nunes, Carlos Sancineto; Schelini, Patricia Waltz; Pasian, Sonia Regina; Homsi, Silvia Vertoni; Moretti, Lucia; Anache, Alexandra Ayach

    2010-01-01

    An adaptation of the standard battery of Woodcock-Johnson III Tests of Cognitive Abilities (WJ-III) for Brazilian children and youth was investigated. The sample was composed of 1094 students (54 percent girls), ages 7-17, living in Sao Paulo state (91 percent). Items from Brazilian school books as well as from the WJ-III Spanish version…

  15. Computerized Adaptive Testing with Multiple-Form Structures

    ERIC Educational Resources Information Center

    Armstrong, Ronald D.; Jones, Douglas H.; Koppel, Nicole B.; Pashley, Peter J.

    2004-01-01

    A multiple-form structure (MFS) is an ordered collection or network of testlets (i.e., sets of items). An examinee's progression through the network of testlets is dictated by the correctness of an examinee's answers, thereby adapting the test to his or her trait level. The collection of paths through the network yields the set of all possible…

  16. A New Stopping Rule for Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Choi, Seung W.; Grady, Matthew W.; Dodd, Barbara G.

    2011-01-01

    The goal of the current study was to introduce a new stopping rule for computerized adaptive testing (CAT). The predicted standard error reduction (PSER) stopping rule uses the predictive posterior variance to determine the reduction in standard error that would result from the administration of additional items. The performance of the PSER was…

  17. Multiple Maximum Exposure Rates in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Ramon Barrada, Juan; Veldkamp, Bernard P.; Olea, Julio

    2009-01-01

    Computerized adaptive testing is subject to security problems, as the item bank content remains operative over long periods and administration time is flexible for examinees. Spreading the content of a part of the item bank could lead to an overestimation of the examinees' trait level. The most common way of reducing this risk is to impose a…

  18. Alpha-Stratified Multistage Computerized Adaptive Testing with beta Blocking.

    ERIC Educational Resources Information Center

    Chang, Hua-Hua; Qian, Jiahe; Yang, Zhiliang

    2001-01-01

    Proposed a refinement, based on the stratification of items developed by D. Weiss (1973), of the computerized adaptive testing item selection procedure of H. Chang and Z. Ying (1999). Simulation studies using an item bank from the Graduate Record Examination show the benefits of the new procedure. (SLD)

  19. Application of the Bifactor Model to Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Seo, Dong Gi

    2011-01-01

    Most computerized adaptive tests (CAT) have been studied under the framework of unidimensional item response theory. However, many psychological variables are multidimensional and might benefit from using a multidimensional approach to CAT. In addition, a number of psychological variables (e.g., quality of life, depression) can be conceptualized…

  20. Computer Adaptive Testing for Small Scale Programs and Instructional Systems

    ERIC Educational Resources Information Center

    Rudner, Lawrence M.; Guo, Fanmin

    2011-01-01

    This study investigates measurement decision theory (MDT) as an underlying model for computer adaptive testing when the goal is to classify examinees into one of a finite number of groups. The first analysis compares MDT with a popular item response theory model and finds little difference in terms of the percentage of correct classifications. The…

  1. 21. DREDGING POND USED TO TEST THE ADAPTABILITY OF JET ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. DREDGING POND USED TO TEST THE ADAPTABILITY OF JET PUMPS FOR PUMPING SAND, AND WEAR RATES OF DIFFERENT TYPES OF DREDGING PIPE. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  2. DIF Analysis for Pretest Items in Computer-Adaptive Testing.

    ERIC Educational Resources Information Center

    Zwick, Rebecca; And Others

    A simulation study of methods of assessing differential item functioning (DIF) in computer-adaptive tests (CATs) was conducted by Zwick, Thayer, and Wingersky (in press, 1993). Results showed that modified versions of the Mantel-Haenszel and standardization methods work well with CAT data. DIF methods were also investigated for nonadaptive…

  3. A Monte Carlo Approach for Adaptive Testing with Content Constraints

    ERIC Educational Resources Information Center

    Belov, Dmitry I.; Armstrong, Ronald D.; Weissman, Alexander

    2008-01-01

    This article presents a new algorithm for computerized adaptive testing (CAT) when content constraints are present. The algorithm is based on shadow CAT methodology to meet content constraints but applies Monte Carlo methods and provides the following advantages over shadow CAT: (a) lower maximum item exposure rates, (b) higher utilization of the…

  4. A Framework for the Development of Computerized Adaptive Tests

    ERIC Educational Resources Information Center

    Thompson, Nathan A.; Weiss, David J.

    2011-01-01

    A substantial amount of research has been conducted over the past 40 years on technical aspects of computerized adaptive testing (CAT), such as item selection algorithms, item exposure controls, and termination criteria. However, there is little literature providing practical guidance on the development of a CAT. This paper seeks to collate some…

  5. Adapting Tests for Use in Multiple Languages and Cultures. Laboratory of Psychometric and Evaluative Research Report.

    ERIC Educational Resources Information Center

    Hambleton, Ronald K.; Patsula, Liane

    Whatever the purpose of test adaptation, questions arise concerning the validity of inferences from such adapted tests. This paper considers several advantages and disadvantages of adapting tests from one language and culture to another. The paper also reviews several sources of error or invalidity associated with adapting tests and suggests ways…

  6. Micro-hybrid electric vehicle application of valve-regulated lead-acid batteries in absorbent glass mat technology: Testing a partial-state-of-charge operation strategy

    NASA Astrophysics Data System (ADS)

    Schaeck, S.; Stoermer, A. O.; Hockgeiger, E.

    The BMW Group has launched two micro-hybrid functions in high volume models in order to contribute to reduction of fuel consumption in modern passenger cars. Both the brake energy regeneration (BER) and the auto-start-stop function (ASSF) are based on the conventional 14 V vehicle electrical system and current series components with only little modifications. An intelligent control algorithm of the alternator enables recuperative charging in braking and coasting phases, known as BER. By switching off the internal combustion engine at a vehicle standstill the idling fuel consumption is effectively reduced by ASSF. By reason of economy and package a lead-acid battery is used as electrochemical energy storage device. The BMW Group assembles valve-regulated lead-acid (VRLA) batteries in absorbent glass mat (AGM) technology in the micro-hybrid electrical power system since special challenges arise for the batteries. By field data analysis a lower average state-of-charge (SOC) due to partial state-of-charge (PSOC) operation and a higher cycling rate due to BER and ASSF are confirmed in this article. Similar to a design of experiment (DOE) like method we present a long-term lab investigation. Two types of 90 Ah VRLA AGM batteries are operated with a test bench profile that simulates the micro-hybrid vehicle electrical system under varying conditions. The main attention of this lab testing is focused on capacity loss and charge acceptance over cycle life. These effects are put into context with periodically refresh charging the batteries in order to prevent accelerated battery aging due to hard sulfation. We demonstrate the positive effect of refresh chargings concerning preservation of battery charge acceptance. Furthermore, we observe moderate capacity loss over 90 full cycles both at 25 °C and at 3 °C battery temperature.

  7. Approaching sign language test construction: adaptation of the German sign language receptive skills test.

    PubMed

    Haug, Tobias

    2011-01-01

    There is a current need for reliable and valid test instruments in different countries in order to monitor deaf children's sign language acquisition. However, very few tests are commercially available that offer strong evidence for their psychometric properties. A German Sign Language (DGS) test focusing on linguistic structures that are acquired in preschool- and school-aged children (4-8 years old) is urgently needed. Using the British Sign Language Receptive Skills Test, that has been standardized and has sound psychometric properties, as a template for adaptation thus provides a starting point for tests of a sign language that is less documented, such as DGS. This article makes a novel contribution to the field by examining linguistic, cultural, and methodological issues in the process of adapting a test from the source language to the target language. The adapted DGS test has sound psychometric properties and provides the basis for revision prior to standardization.

  8. Testing for local adaptation in brown trout using reciprocal transplants

    PubMed Central

    2012-01-01

    Background Local adaptation can drive the divergence of populations but identification of the traits under selection remains a major challenge in evolutionary biology. Reciprocal transplant experiments are ideal tests of local adaptation, yet rarely used for higher vertebrates because of the mobility and potential invasiveness of non-native organisms. Here, we reciprocally transplanted 2500 brown trout (Salmo trutta) embryos from five populations to investigate local adaptation in early life history traits. Embryos were bred in a full-factorial design and raised in natural riverbeds until emergence. Customized egg capsules were used to simulate the natural redd environment and allowed tracking the fate of every individual until retrieval. We predicted that 1) within sites, native populations would outperform non-natives, and 2) across sites, populations would show higher performance at ‘home’ compared to ‘away’ sites. Results There was no evidence for local adaptation but we found large differences in survival and hatching rates between sites, indicative of considerable variation in habitat quality. Survival was generally high across all populations (55% ± 3%), but ranged from 4% to 89% between sites. Average hatching rate was 25% ± 3% across populations ranging from 0% to 62% between sites. Conclusion This study provides rare empirical data on variation in early life history traits in a population network of a salmonid, and large-scale breeding and transplantation experiments like ours provide powerful tests for local adaptation. Despite the recently reported genetic and morphological differences between the populations in our study area, local adaptation at the embryo level is small, non-existent, or confined to ecological conditions that our experiment could not capture. PMID:23249365

  9. MatMCNP

    SciTech Connect

    2015-10-19

    A code for generating MCNP material cards (MatMCNP) has been written and verified for naturally occurring, stable isotopes. The program allows for material specification as either atomic or weight percent (fractions). MatMCNP also permits the specification of enriched lithium, boron, and/or uranium. In addition to producing the material cards for MCNP, the code calculates the atomic (or number) density in atoms/barn-cm as well as the multiplier that should be used to convert neutron and gamma fluences into dose in the material specified.

  10. Adaptive Set-Based Methods for Association Testing.

    PubMed

    Su, Yu-Chen; Gauderman, William James; Berhane, Kiros; Lewinger, Juan Pablo

    2016-02-01

    With a typical sample size of a few thousand subjects, a single genome-wide association study (GWAS) using traditional one single nucleotide polymorphism (SNP)-at-a-time methods can only detect genetic variants conferring a sizable effect on disease risk. Set-based methods, which analyze sets of SNPs jointly, can detect variants with smaller effects acting within a gene, a pathway, or other biologically relevant sets. Although self-contained set-based methods (those that test sets of variants without regard to variants not in the set) are generally more powerful than competitive set-based approaches (those that rely on comparison of variants in the set of interest with variants not in the set), there is no consensus as to which self-contained methods are best. In particular, several self-contained set tests have been proposed to directly or indirectly "adapt" to the a priori unknown proportion and distribution of effects of the truly associated SNPs in the set, which is a major determinant of their power. A popular adaptive set-based test is the adaptive rank truncated product (ARTP), which seeks the set of SNPs that yields the best-combined evidence of association. We compared the standard ARTP, several ARTP variations we introduced, and other adaptive methods in a comprehensive simulation study to evaluate their performance. We used permutations to assess significance for all the methods and thus provide a level playing field for comparison. We found the standard ARTP test to have the highest power across our simulations followed closely by the global model of random effects (GMRE) and a least absolute shrinkage and selection operator (LASSO)-based test.

  11. A Multiple Objective Test Assembly Approach for Exposure Control Problems in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Veldkamp, Bernard P.; Verschoor, Angela J.; Eggen, Theo J. H. M.

    2010-01-01

    Overexposure and underexposure of items in the bank are serious problems in operational computerized adaptive testing (CAT) systems. These exposure problems might result in item compromise, or point at a waste of investments. The exposure control problem can be viewed as a test assembly problem with multiple objectives. Information in the test has…

  12. Development and Simulation Testing of a Computerized Adaptive Version of the Philadelphia Naming Test

    ERIC Educational Resources Information Center

    Hula, William D.; Kellough, Stacey; Fergadiotis, Gerasimos

    2015-01-01

    Purpose: The purpose of this study was to develop a computerized adaptive test (CAT) version of the Philadelphia Naming Test (PNT; Roach, Schwartz, Martin, Grewal, & Brecher, 1996), to reduce test length while maximizing measurement precision. This article is a direct extension of a companion article (Fergadiotis, Kellough, & Hula, 2015),…

  13. A New Stopping Rule for Computerized Adaptive Testing.

    PubMed

    Choi, Seung W; Grady, Matthew W; Dodd, Barbara G

    2010-12-01

    The goal of the current study was to introduce a new stopping rule for computerized adaptive testing. The predicted standard error reduction stopping rule (PSER) uses the predictive posterior variance to determine the reduction in standard error that would result from the administration of additional items. The performance of the PSER was compared to that of the minimum standard error stopping rule and a modified version of the minimum information stopping rule in a series of simulated adaptive tests, drawn from a number of item pools. Results indicate that the PSER makes efficient use of CAT item pools, administering fewer items when predictive gains in information are small and increasing measurement precision when information is abundant.

  14. Biogeochemistry of Microbial Mats

    NASA Technical Reports Server (NTRS)

    DesMarais, David J.; DeVincenizi, D. (Technical Monitor)

    2002-01-01

    The hierarchical organization of microbial ecosystems determines the rates of processes that shape Earth's environment, define the stage upon which major evolutionary events occurred, and create biosignatures in sediments and atmospheres. In cyanobacterial mats, oxygenic photosynthesis provides energy, organic substrates and oxygen to the ecosystem. Incident light changes with depth in the mat, both in intensity and spectral composition, and counteracting gradients of oxygen and sulfide shape the chemical microenvironment. A combination of benefits and hazards of light, oxygen and sulfide promotes the allocation of the various essential mat processes between light and dark periods and to various depths in the mat. Microliters produce hydrogen, small organic acids, nitrogen and sulfur species. Such compounds fuel a flow of energy and electrons in these ecosystems and thus shape interactions between groups of microorganisms. Coordinated observations of population distribution, abundance, and activity for an entire community are making fundamental questions in ecology accessible. These questions address those factors that sustain the remarkable diversity of microorganisms that are now being revealed by molecular techniques. These questions also target the processes that shape the various kinds of biosignatures that we will seek, both in ancient rocks from Earth and Mars, and in atmospheres of distant planets beyond our Solar System.

  15. Adaptive Test Schemes for Control of Paratuberculosis in Dairy Cows

    PubMed Central

    Græsbøll, Kaare; Nielsen, Søren Saxmose; Christiansen, Lasse Engbo; Toft, Nils; Halasa, Tariq

    2016-01-01

    Paratuberculosis is a chronic infection that in dairy cattle causes reduced milk yield, weight loss, and ultimately fatal diarrhea. Subclinical animals can excrete bacteria (Mycobacterium avium ssp. paratuberculosis, MAP) in feces and infect other animals. Farmers identify the infectious animals through a variety of test-strategies, but are challenged by the lack of perfect tests. Frequent testing increases the sensitivity but the costs of testing are a cause of concern for farmers. Here, we used a herd simulation model using milk ELISA tests to evaluate the epidemiological and economic consequences of continuously adapting the sampling interval in response to the estimated true prevalence in the herd. The key results were that the true prevalence was greatly affected by the hygiene level and to some extent by the test-frequency. Furthermore, the choice of prevalence that will be tolerated in a control scenario had a major impact on the true prevalence in the normal hygiene setting, but less so when the hygiene was poor. The net revenue is not greatly affected by the test-strategy, because of the general variation in net revenues between farms. An exception to this is the low hygiene herd, where frequent testing results in lower revenue. When we look at the probability of eradication, then it is correlated with the testing frequency and the target prevalence during the control phase. The probability of eradication is low in the low hygiene herd, and a test-and-cull strategy should probably not be the primary strategy in this herd. Based on this study we suggest that, in order to control MAP, the standard Danish dairy farm should use an adaptive strategy where a short sampling interval of three months is used when the estimated true prevalence is above 1%, and otherwise use a long sampling interval of one year. PMID:27907192

  16. Interferometric homogeneity test using adaptive frequency comb illumination.

    PubMed

    Mantel, Klaus; Schwider, Johannes

    2013-03-20

    The homogeneity test of glass plates in a Fizeau interferometer requires the measurement of the glass sample in reflected as well as in transmitted light. For the measurement in transmitted light, the sample has to be inserted into the ray path of a Fizeau or Twyman-Green interferometer, which leads to a nested cavity setup. To separate the interference signals from the different cavities, we illuminate a Fizeau interferometer with an adaptive frequency comb. In this way, rigid glass plates can be measured, and linear variations in the homogeneity can also be detected. The adaptive frequency comb is provided by a variable Fabry-Perot filter under broadband illumination from a superluminescence diode. Compared to approaches using a two-beam interferometer as a filter for the broadband light source, the visibility of the fringe system is considerably higher.

  17. Adaptation to Room Acoustics Using the Modified Rhyme Test

    PubMed Central

    Brandewie, Eugene; Zahorik, Pavel

    2012-01-01

    The negative effect of reverberant sound energy on speech intelligibility is well documented. Recently, however, prior exposure to room acoustics has been shown to increase intelligibility for a number of listeners in simulated room environments. This room adaptation effect, a possible extension of dynamic echo suppression, has been shown to be specific to reverberant rooms and requires binaural input. Because this effect has been demonstrated only using the Coordinated Response Measure (CRM) corpus it is important to determine whether the increase in intelligibility scores reported previously was due to the specific nature of the CRM task. Here we demonstrate a comparable room-acoustic effect using the Modified Rhyme Test (MRT) corpus in multiple room environments. The results are consistent with the idea that the room adaptation effect may be a natural phenomenon of listening in reverberant environments. PMID:23437415

  18. Modeling Student Test-Taking Motivation in the Context of an Adaptive Achievement Test

    ERIC Educational Resources Information Center

    Wise, Steven L.; Kingsbury, G. Gage

    2016-01-01

    This study examined the utility of response time-based analyses in understanding the behavior of unmotivated test takers. For the data from an adaptive achievement test, patterns of observed rapid-guessing behavior and item response accuracy were compared to the behavior expected under several types of models that have been proposed to represent…

  19. Person Fit Analysis in Computerized Adaptive Testing Using Tests for a Change Point

    ERIC Educational Resources Information Center

    Sinharay, Sandip

    2016-01-01

    Meijer and van Krimpen-Stoop noted that the number of person-fit statistics (PFSs) that have been designed for computerized adaptive tests (CATs) is relatively modest. This article partially addresses that concern by suggesting three new PFSs for CATs. The statistics are based on tests for a change point and can be used to detect an abrupt change…

  20. Igniter adapter-to-igniter chamber deflection test

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1990-01-01

    Testing was performed to determine the maximum RSRM igniter adapter-to-igniter chamber joint deflection at the crown of the inner joint primary seal. The deflection data was gathered to support igniter inner joint gasket resiliency predictions which led to launch commit criteria temperature determinations. The proximity (deflection) gage holes for the first test (Test No. 1) were incorrectly located; therefore, the test was declared a non-test. Prior to Test No. 2, test article configuration was modified with the correct proximity gage locations. Deflection data were successfully acquired during Test No. 2. However, the proximity gage deflection measurements were adversely affected by temperature increases. Deflections measured after the temperature rise at the proximity gages were considered unreliable. An analysis was performed to predict the maximum deflections based on the reliable data measured before the detectable temperature rise. Deflections to the primary seal crown location were adjusted to correspond to the time of maximum expected operating pressure (2,159 psi) to account for proximity gage bias, and to account for maximum attach and special bolt relaxation. The maximum joint deflection for the igniter inner joint at the crown of the primary seal, accounting for all significant correction factors, was 0.0031 in. (3.1 mil). Since the predicted (0.003 in.) and tested maximum deflection values were sufficiently close, the launch commit criteria was not changed as a result of this test. Data from this test should be used to determine if the igniter inner joint gasket seals are capable of maintaining sealing capability at a joint displacement of (1.4) x (0.0031 in.) = 0.00434 inches. Additional testing should be performed to increase the database on igniter deflections and address launch commit criteria temperatures.

  1. Testing the Apodized Pupil Lyot Coronagraph on the Laboratory for Adaptive Optics Extreme Adaptive Optics Testbed

    NASA Astrophysics Data System (ADS)

    Thomas, Sandrine J.; Soummer, Rémi; Dillon, Daren; Macintosh, Bruce; Gavel, Donald; Sivaramakrishnan, Anand

    2011-10-01

    We present testbed results of the Apodized Pupil Lyot Coronagraph (APLC) at the Laboratory for Adaptive Optics (LAO). These results are part of the validation and tests of the coronagraph and of the Extreme Adaptive Optics (ExAO) for the Gemini Planet Imager (GPI). The apodizer component is manufactured with a halftone technique using black chrome microdots on glass. Testing this APLC (like any other coronagraph) requires extremely good wavefront correction, which is obtained to the 1 nm rms level using the microelectricalmechanical systems (MEMS) technology, on the ExAO visible testbed of the LAO at the University of Santa Cruz. We used an APLC coronagraph without central obstruction, both with a reference super-polished flat mirror and with the MEMS to obtain one of the first images of a dark zone in a coronagraphic image with classical adaptive optics using a MEMS deformable mirror (without involving dark hole algorithms). This was done as a complementary test to the GPI coronagraph testbed at American Museum of Natural History, which studied the coronagraph itself without wavefront correction. Because we needed a full aperture, the coronagraph design is very different from the GPI design. We also tested a coronagraph with central obstruction similar to that of GPI. We investigated the performance of the APLC coronagraph and more particularly the effect of the apodizer profile accuracy on the contrast. Finally, we compared the resulting contrast to predictions made with a wavefront propagation model of the testbed to understand the effects of phase and amplitude errors on the final contrast.

  2. TESTING THE APODIZED PUPIL LYOT CORONAGRAPH ON THE LABORATORY FOR ADAPTIVE OPTICS EXTREME ADAPTIVE OPTICS TESTBED

    SciTech Connect

    Thomas, Sandrine J.; Dillon, Daren; Gavel, Donald; Macintosh, Bruce; Sivaramakrishnan, Anand E-mail: dillon@ucolick.org E-mail: soummer@stsci.edu E-mail: anand@amnh.org

    2011-10-15

    We present testbed results of the Apodized Pupil Lyot Coronagraph (APLC) at the Laboratory for Adaptive Optics (LAO). These results are part of the validation and tests of the coronagraph and of the Extreme Adaptive Optics (ExAO) for the Gemini Planet Imager (GPI). The apodizer component is manufactured with a halftone technique using black chrome microdots on glass. Testing this APLC (like any other coronagraph) requires extremely good wavefront correction, which is obtained to the 1 nm rms level using the microelectricalmechanical systems (MEMS) technology, on the ExAO visible testbed of the LAO at the University of Santa Cruz. We used an APLC coronagraph without central obstruction, both with a reference super-polished flat mirror and with the MEMS to obtain one of the first images of a dark zone in a coronagraphic image with classical adaptive optics using a MEMS deformable mirror (without involving dark hole algorithms). This was done as a complementary test to the GPI coronagraph testbed at American Museum of Natural History, which studied the coronagraph itself without wavefront correction. Because we needed a full aperture, the coronagraph design is very different from the GPI design. We also tested a coronagraph with central obstruction similar to that of GPI. We investigated the performance of the APLC coronagraph and more particularly the effect of the apodizer profile accuracy on the contrast. Finally, we compared the resulting contrast to predictions made with a wavefront propagation model of the testbed to understand the effects of phase and amplitude errors on the final contrast.

  3. Electronic Quality of Life Assessment Using Computer-Adaptive Testing

    PubMed Central

    2016-01-01

    Background Quality of life (QoL) questionnaires are desirable for clinical practice but can be time-consuming to administer and interpret, making their widespread adoption difficult. Objective Our aim was to assess the performance of the World Health Organization Quality of Life (WHOQOL)-100 questionnaire as four item banks to facilitate adaptive testing using simulated computer adaptive tests (CATs) for physical, psychological, social, and environmental QoL. Methods We used data from the UK WHOQOL-100 questionnaire (N=320) to calibrate item banks using item response theory, which included psychometric assessments of differential item functioning, local dependency, unidimensionality, and reliability. We simulated CATs to assess the number of items administered before prespecified levels of reliability was met. Results The item banks (40 items) all displayed good model fit (P>.01) and were unidimensional (fewer than 5% of t tests significant), reliable (Person Separation Index>.70), and free from differential item functioning (no significant analysis of variance interaction) or local dependency (residual correlations < +.20). When matched for reliability, the item banks were between 45% and 75% shorter than paper-based WHOQOL measures. Across the four domains, a high standard of reliability (alpha>.90) could be gained with a median of 9 items. Conclusions Using CAT, simulated assessments were as reliable as paper-based forms of the WHOQOL with a fraction of the number of items. These properties suggest that these item banks are suitable for computerized adaptive assessment. These item banks have the potential for international development using existing alternative language versions of the WHOQOL items. PMID:27694100

  4. Development of a Computerized Adaptive Test for Schizotypy Assessment

    PubMed Central

    Fonseca-Pedrero, Eduardo; Menéndez, Luis Fernando; Paino, Mercedes; Lemos-Giráldez, Serafín; Muñiz, José

    2013-01-01

    Background Schizotypal traits in adolescents from the general population represent the behavioral expression of liability for psychotic disorders. Schizotypy assessment in this sector of population has advanced considerably in the last few years; however, it is necessary to incorporate recent advances in psychological and educational measurement. Objective The main goal of this study was to develop a Computerized Adaptive Test (CAT) to evaluate schizotypy through “The Oviedo Questionnaire for Schizotypy Assessment” (ESQUIZO-Q), in non-clinical adolescents. Methods The final sample consisted of 3,056 participants, 1,469 males, with a mean age of 15.9 years (SD = 1.2). Results The results indicated that the ESQUIZO-Q scores presented adequate psychometric properties under both Classical Test Theory and Item Response Theory. The Information Function estimated using the Gradual Response Model indicated that the item pool effectively assesses schizotypy at the high end of the latent trait. The correlation between the CAT total scores and the paper-and-pencil test was 0.92. The mean number of presented items in the CAT with the standard error fixed at ≤0.30 was of 34 items. Conclusion The CAT showed adequate psychometric properties for schizotypy assessment in the general adolescent population. The ESQUIZO-Q adaptive version could be used as a screening method for the detection of adolescents at risk for psychosis in both educational and mental health settings. PMID:24019907

  5. Investigation of VEGGIE Root Mat

    NASA Technical Reports Server (NTRS)

    Subbiah, Arun M.

    2013-01-01

    VEGGIE is a plant growth facility that utilizes the phenomenon of capillary action as its primary watering system. A cloth made of Meta Aramid fiber, known as Nomex is used to wick water up from a reservoir to the bottom of the plants roots. This root mat system is intended to be low maintenance with no moving parts and requires minimal crew interface time. Unfortunately, the water wicking rates are inconsistent throughout the plant life cycle, thus causing plants to die. Over-wicking of water occurs toward the beginning of the cycle, while under-wicking occurs toward the middle. This inconsistency of wicking has become a major issue, drastically inhibiting plant growth. The primary objective is to determine the root cause of the inconsistent wicking through experimental testing. Suspect causes for the capillary water column to break include: a vacuum effect due to a negative pressure gradient in the water reservoir, contamination of material due to minerals in water and back wash from plant fertilizer, induced air bubbles while using syringe refill method, and material limitations of Nomex's ability to absorb and retain water. Experimental testing will be conducted to systematically determine the cause of under and over-wicking. Pressure gages will be used to determine pressure drop during the course of the plant life cycle and during the water refill process. A debubbler device will be connected to a root mat in order to equalize pressure inside the reservoir. Moisture and evaporation tests will simultaneously be implemented to observe moisture content and wicking rates over the course of a plant cycle. Water retention tests will be performed using strips of Nomex to determine materials wicking rates, porosity, and absorptivity. Through these experimental tests, we will have a better understanding of material properties of Nomex, as well as determine the root cause of water column breakage. With consistent test results, a forward plan can be achieved to resolve

  6. Reading Test-Sentence Comprehension: An Adapted Version of Lobrot's Lecture 3 Test for Brazilian Portuguese.

    PubMed

    de Araújo Vilhena, Douglas; Sucena, Ana; Castro, São Luís; Pinheiro, Ângela Maria Vieira

    2016-02-01

    Our aim was to analyse the linguistic structure of the Lobrot's Lecture 3 (L3) reading test and to describe the procedure for its adaptation to a Brazilian cultural-linguistic context. The resulting adapted version is called the Reading Test-Sentence Comprehension [Teste de Leitura: Compreensão de Sentenças (TELCS)] and was developed using the European Portuguese adaptation of L3 as a reference. The present study was conducted in seven steps: (1) classification of the response alternatives of L3 test; (2) adaptation of the original sentences into Brazilian Portuguese; (3) back-translation; (4) adaptation of the distractors from TELCS; (5) configuration of TELCS; (6) pilot study; and (7) validation and standardization. In comparison with L3, TELCS included new linguistic and structural variables, such as frequency of occurrence of the distractors, gender neutrality and position of the target words. The instrument can be used for a collective screening or individual clinical administration purposes to evaluate the reading ability of second-to-fifth-grade and 7-to-11-year-old students.

  7. Multistage Adaptive Testing for a Large-Scale Classification Test: Design, Heuristic Assembly, and Comparison with Other Testing Modes. ACT Research Report Series, 2012 (6)

    ERIC Educational Resources Information Center

    Zheng, Yi; Nozawa, Yuki; Gao, Xiaohong; Chang, Hua-Hua

    2012-01-01

    Multistage adaptive tests (MSTs) have gained increasing popularity in recent years. MST is a balanced compromise between linear test forms (i.e., paper-and-pencil testing and computer-based testing) and traditional item-level computer-adaptive testing (CAT). It combines the advantages of both. On one hand, MST is adaptive (and therefore more…

  8. Microbial mats and the early evolution of life

    NASA Technical Reports Server (NTRS)

    Des Marais, D. J.

    1990-01-01

    Microbial mats have descended from perhaps the oldest and most widespread biological communities known. Mats harbor microbes that are crucial for studies of bacterial phylogeny and physiology. They illustrate how several oxygen-sensitive biochemical processes have adapted to oxygen, and they show how life adapted to dry land long before the rise of plants. The search for the earliest grazing protists and metazoa in stromatolites is aided by observations of mats: in them, organic compounds characteristic of ancient photosynthetic protists can be identified. Recent mat studies suggest that the 13C/12C increase observed over geological time in stromatolitic organic matter was driven at least in part by a long-term decline in atmospheric carbon dioxide levels.

  9. A Facile Approach for the Mass Production of Submicro/Micro Poly (Lactic Acid) Fibrous Mats and Their Cytotoxicity Test towards Neural Stem Cells

    PubMed Central

    2016-01-01

    Despite many of the studies being conducted, the electrospinning of poly (lactic acid) (PLA), dissolved in its common solvents, is difficult to be continuously processed for mass production. This is due to the polymer solution droplet drying. Besides, the poor stretching capability of the polymer solution limits the production of small diameter fibers. To address these issues, we have examined the two following objectives: first, using an appropriate solvent system for the mass production of fibrous mats with fine-tunable fiber diameters; second, nontoxicity of the mats towards Neural Stem Cell (NSC). To this aim, TFA (trifluoroacetic acid) was used as a cosolvent, in a mixture with DCM (dichloromethane), and the solution viscosity, surface tension, electrical conductivity, and the continuity of the electrospinning process were compared with the solutions prepared with common single solvents. The binary solvent facilitated PLA electrospinning, resulting in a long lasting, stable electrospinning condition, due to the low surface tension and high conductivity of the binary-solvent system. The fiber diameter was tailored from nano to micro by varying effective parameters and examined by scanning electron microscopy (SEM) and image-processing software. Laminin-coated electrospun mats supported NSC expansion and spreading, as examined using AlamarBlue assay and fluorescent microscopy, respectively. PMID:27699177

  10. An Adaptive Genetic Association Test Using Double Kernel Machines.

    PubMed

    Zhan, Xiang; Epstein, Michael P; Ghosh, Debashis

    2015-10-01

    Recently, gene set-based approaches have become very popular in gene expression profiling studies for assessing how genetic variants are related to disease outcomes. Since most genes are not differentially expressed, existing pathway tests considering all genes within a pathway suffer from considerable noise and power loss. Moreover, for a differentially expressed pathway, it is of interest to select important genes that drive the effect of the pathway. In this article, we propose an adaptive association test using double kernel machines (DKM), which can both select important genes within the pathway as well as test for the overall genetic pathway effect. This DKM procedure first uses the garrote kernel machines (GKM) test for the purposes of subset selection and then the least squares kernel machine (LSKM) test for testing the effect of the subset of genes. An appealing feature of the kernel machine framework is that it can provide a flexible and unified method for multi-dimensional modeling of the genetic pathway effect allowing for both parametric and nonparametric components. This DKM approach is illustrated with application to simulated data as well as to data from a neuroimaging genetics study.

  11. Development and field testing of an adaptive power factor controller

    SciTech Connect

    El-Sharkawi, M.; Venkata, S.S.; Butler, N.G.; Yinger, R.W.

    1987-12-01

    The Adaptive Power Factor Controller (APFC) is a device that switches capacitors electronically to achieve almost unity power factor at the point of installation. It was designed and developed at the University of Washington (UW), and is being tested at the R and D facility of the Southern California Edison Company (SCE). It is particularly intended for loads with dynamically varying reactive power demands such as induction generators in wind power stations, or cyclically changing loads such as induction motors in process industries. It is also ideally suited for improving the power factor profile of a distribution line. The purposes of this paper are two-fold: to explain the most recent design of the 50-kVAR APFC and to report the results of the field testing program on the device after it was installed at the terminals of a 50-kW three-phase induction generator located at the Dever Wind R and D site of SCE.

  12. Developing new online calibration methods for multidimensional computerized adaptive testing.

    PubMed

    Chen, Ping; Wang, Chun; Xin, Tao; Chang, Hua-Hua

    2017-02-01

    Multidimensional computerized adaptive testing (MCAT) has received increasing attention over the past few years in educational measurement. Like all other formats of CAT, item replenishment is an essential part of MCAT for its item bank maintenance and management, which governs retiring overexposed or obsolete items over time and replacing them with new ones. Moreover, calibration precision of the new items will directly affect the estimation accuracy of examinees' ability vectors. In unidimensional CAT (UCAT) and cognitive diagnostic CAT, online calibration techniques have been developed to effectively calibrate new items. However, there has been very little discussion of online calibration in MCAT in the literature. Thus, this paper proposes new online calibration methods for MCAT based upon some popular methods used in UCAT. Three representative methods, Method A, the 'one EM cycle' method and the 'multiple EM cycles' method, are generalized to MCAT. Three simulation studies were conducted to compare the three new methods by manipulating three factors (test length, item bank design, and level of correlation between coordinate dimensions). The results showed that all the new methods were able to recover the item parameters accurately, and the adaptive online calibration designs showed some improvements compared to the random design under most conditions.

  13. Design of the Dual Conjugate Adaptive Optics Test-bed

    NASA Astrophysics Data System (ADS)

    Sharf, Inna; Bell, K.; Crampton, D.; Fitzsimmons, J.; Herriot, Glen; Jolissaint, Laurent; Lee, B.; Richardson, H.; van der Kamp, D.; Veran, Jean-Pierre

    In this paper, we describe the Multi-Conjugate Adaptive Optics laboratory test-bed presently under construction at the University of Victoria, Canada. The test-bench will be used to support research in the performance of multi-conjugate adaptive optics, turbulence simulators, laser guide stars and miniaturizing adaptive optics. The main components of the test-bed include two micro-machined deformable mirrors, a tip-tilt mirror, four wavefront sensors, a source simulator, a dual-layer turbulence simulator, as well as computational and control hardware. The paper will describe in detail the opto-mechanical design of the adaptive optics module, the design of the hot-air turbulence generator and the configuration chosen for the source simulator. Below, we present a summary of these aspects of the bench. The optical and mechanical design of the test-bed has been largely driven by the particular choice of the deformable mirrors. These are continuous micro-machined mirrors manufactured by Boston Micromachines Corporation. They have a clear aperture of 3.3 mm and are deformed with 140 actuators arranged in a square grid. Although the mirrors have an open-loop bandwidth of 6.6 KHz, their shape can be updated at a sampling rate of 100 Hz. In our optical design, the mirrors are conjugated at 0km and 10 km in the atmosphere. A planar optical layout was achieved by using four off-axis paraboloids and several folding mirrors. These optics will be mounted on two solid blocks which can be aligned with respect to each other. The wavefront path design accommodates 3 monochromatic guide stars that can be placed at either 90 km or at infinity. The design relies on the natural separation of the beam into 3 parts because of differences in locations of the guide stars in the field of view. In total four wavefront sensors will be procured from Adaptive Optics Associates (AOA) or built in-house: three for the guide stars and the fourth to collect data from the science source output in

  14. ESO adaptive optics facility progress and first laboratory test results

    NASA Astrophysics Data System (ADS)

    Arsenault, Robin; Madec, Pierre-Yves; Paufique, Jérome; La Penna, Paolo; Stroebele, Stefan; Vernet, Elise; Pirard, Jean-Francois; Hackenberg, Wolfgang; Kuntschner, Harald; Kolb, Johann; Muller, Nicolas; Garcia-Rissmann, Aurea; Le Louarn, Miska; Amico, Paola; Hubin, Norbert; Lizon, Jean-Louis; Ridings, Rob; Haguenauer, Pierre; Abad, Jose A.; Fischer, Gerhard; Heinz, Volker; Kiekebusch, Mario; Argomedo, Javier; Conzelmann, Ralf; Tordo, Sebastien; Donaldson, Rob; Soenke, Christian; Duhoux, Philippe; Fedrigo, Enrico; Delabre, Bernard; Jost, Andrea; Duchateau, Michel; Downing, Mark; Reyes Moreno, Javier; Manescau, Antonio; Bonaccini Calia, Domenico; Quattri, Marco; Dupuy, Christophe; Guidolin, Ivan M.; Comin, Mauro; Guzman, Ronald; Buzzoni, Bernard; Quentin, Jutta; Lewis, Steffan; Jolley, Paul; Kraus, Max; Pfrommer, Thomas; Biasi, Roberto; Gallieni, Daniele; Stuik, Remko; Kaenders, Wilhelm; Ernstberger, Bernhard; Friedenauer, Axel

    2014-07-01

    The Adaptive Optics Facility project is completing the integration of its systems at ESO Headquarters in Garching. The main test bench ASSIST and the 2nd Generation M2-Unit (hosting the Deformable Secondary Mirror) have been granted acceptance late 2012. The DSM has undergone a series of tests on ASSIST in 2013 which have validated its optical performance and launched the System Test Phase of the AOF. This has been followed by the performance evaluation of the GRAAL natural guide star mode on-axis and will continue in 2014 with its Ground Layer AO mode. The GALACSI module (for MUSE) Wide-Field-Mode (GLAO) and the more challenging Narrow-Field-Mode (LTAO) will then be tested. The AOF has also taken delivery of the second scientific thin shell mirror and the first 22 Watt Sodium laser Unit. We will report on the system tests status, the performances evaluated on the ASSIST bench and advancement of the 4Laser Guide Star Facility. We will also present the near future plans for commissioning on the telescope and some considerations on tools to ensure an efficient operation of the Facility in Paranal.

  15. Identifying Differential Item Functioning in Multi-Stage Computer Adaptive Testing

    ERIC Educational Resources Information Center

    Gierl, Mark J.; Lai, Hollis; Li, Johnson

    2013-01-01

    The purpose of this study is to evaluate the performance of CATSIB (Computer Adaptive Testing-Simultaneous Item Bias Test) for detecting differential item functioning (DIF) when items in the matching and studied subtest are administered adaptively in the context of a realistic multi-stage adaptive test (MST). MST was simulated using a 4-item…

  16. Failing Tests: Commentary on "Adapting Educational Measurement to the Demands of Test-Based Accountability"

    ERIC Educational Resources Information Center

    Thissen, David

    2015-01-01

    In "Adapting Educational Measurement to the Demands of Test-Based Accountability" Koretz takes the time-honored engineering approach to educational measurement, identifying specific problems with current practice and proposing minimal modifications of the system to alleviate those problems. In response to that article, David Thissen…

  17. Mutual Information Item Selection Method in Cognitive Diagnostic Computerized Adaptive Testing with Short Test Length

    ERIC Educational Resources Information Center

    Wang, Chun

    2013-01-01

    Cognitive diagnostic computerized adaptive testing (CD-CAT) purports to combine the strengths of both CAT and cognitive diagnosis. Cognitive diagnosis models aim at classifying examinees into the correct mastery profile group so as to pinpoint the strengths and weakness of each examinee whereas CAT algorithms choose items to determine those…

  18. Application of computerized adaptive testing in medical education.

    PubMed

    Huh, Sun

    2009-06-01

    Application of computerized adaptive testing (CAT) in medical education is still spare in the high stakes examination or in the school-based examination. In the medical school in Belgium, CAT was used for an assessment tool in general practice as pilot test was reported. In Hallym University, CAT has been introduced in the evaluation of the students' performance as in-course general evaluation test and parasitology test. Another examples of application of CAT for high stakes examination are Medical Council of Canada Qualifying Examination - Part 1 in Canada and National Council Licensure EXamination - Registered Nurse in USA. CAT has some merits such as accurate estimation of the ability parameters of the examinees and the shorter period of examination. To apply the CAT in medical education more actively, medical teachers should have an interest in the modern measurement theories such as item response theory and technologies. It is still uncertain if CAT may be prosperous in the medical education as a tool for the measurement of the examinees' ability. However, we should prepare the era of application of CAT in high stakes examination such as medical licensing examination.

  19. The Effect of Test and Examinee Characteristics on the Occurrence of Aberrant Response Patterns in a Computerized Adaptive Test

    ERIC Educational Resources Information Center

    Rizavi, Saba; Hariharan, Swaminathan

    2001-01-01

    The advantages that computer adaptive testing offers over linear tests have been well documented. The Computer Adaptive Test (CAT) design is more efficient than the Linear test design as fewer items are needed to estimate an examinee's proficiency to a desired level of precision. In the ideal situation, a CAT will result in examinees answering…

  20. Highly adaptive tests for group differences in brain functional connectivity.

    PubMed

    Kim, Junghi; Pan, Wei

    2015-01-01

    Resting-state functional magnetic resonance imaging (rs-fMRI) and other technologies have been offering evidence and insights showing that altered brain functional networks are associated with neurological illnesses such as Alzheimer's disease. Exploring brain networks of clinical populations compared to those of controls would be a key inquiry to reveal underlying neurological processes related to such illnesses. For such a purpose, group-level inference is a necessary first step in order to establish whether there are any genuinely disrupted brain subnetworks. Such an analysis is also challenging due to the high dimensionality of the parameters in a network model and high noise levels in neuroimaging data. We are still in the early stage of method development as highlighted by Varoquaux and Craddock (2013) that "there is currently no unique solution, but a spectrum of related methods and analytical strategies" to learn and compare brain connectivity. In practice the important issue of how to choose several critical parameters in estimating a network, such as what association measure to use and what is the sparsity of the estimated network, has not been carefully addressed, largely because the answers are unknown yet. For example, even though the choice of tuning parameters in model estimation has been extensively discussed in the literature, as to be shown here, an optimal choice of a parameter for network estimation may not be optimal in the current context of hypothesis testing. Arbitrarily choosing or mis-specifying such parameters may lead to extremely low-powered tests. Here we develop highly adaptive tests to detect group differences in brain connectivity while accounting for unknown optimal choices of some tuning parameters. The proposed tests combine statistical evidence against a null hypothesis from multiple sources across a range of plausible tuning parameter values reflecting uncertainty with the unknown truth. These highly adaptive tests are not only

  1. Highly adaptive tests for group differences in brain functional connectivity

    PubMed Central

    Kim, Junghi; Pan, Wei

    2015-01-01

    Resting-state functional magnetic resonance imaging (rs-fMRI) and other technologies have been offering evidence and insights showing that altered brain functional networks are associated with neurological illnesses such as Alzheimer's disease. Exploring brain networks of clinical populations compared to those of controls would be a key inquiry to reveal underlying neurological processes related to such illnesses. For such a purpose, group-level inference is a necessary first step in order to establish whether there are any genuinely disrupted brain subnetworks. Such an analysis is also challenging due to the high dimensionality of the parameters in a network model and high noise levels in neuroimaging data. We are still in the early stage of method development as highlighted by Varoquaux and Craddock (2013) that “there is currently no unique solution, but a spectrum of related methods and analytical strategies” to learn and compare brain connectivity. In practice the important issue of how to choose several critical parameters in estimating a network, such as what association measure to use and what is the sparsity of the estimated network, has not been carefully addressed, largely because the answers are unknown yet. For example, even though the choice of tuning parameters in model estimation has been extensively discussed in the literature, as to be shown here, an optimal choice of a parameter for network estimation may not be optimal in the current context of hypothesis testing. Arbitrarily choosing or mis-specifying such parameters may lead to extremely low-powered tests. Here we develop highly adaptive tests to detect group differences in brain connectivity while accounting for unknown optimal choices of some tuning parameters. The proposed tests combine statistical evidence against a null hypothesis from multiple sources across a range of plausible tuning parameter values reflecting uncertainty with the unknown truth. These highly adaptive tests are not

  2. Design of Sequentially Randomized Trials for Testing Adaptive Treatment Strategies

    PubMed Central

    Ogbagaber, Semhar B.; Karp, Jordan; Wahed, Abdus S.

    2016-01-01

    An adaptive treatment strategy (ATS) is an outcome-guided algorithm that allows personalized treatment of complex diseases based on patients’ disease status and treatment history. Conditions such as AIDS, depression, and cancer usually require several stages of treatment due to the chronic, multifactorial nature of illness progression and management. Sequential multiple assignment randomized (SMAR) designs permit simultaneous inference about multiple ATSs, where patients are sequentially randomized to treatments at different stages depending upon response status. The purpose of the article is to develop a sample size formula to ensure adequate power for comparing two or more ATSs. Based on a Wald-type statistic for comparing multiple ATSs with a continuous endpoint, we develop a sample size formula and test it through simulation studies. We show via simulation that the proposed sample size formula maintains the nominal power. The proposed sample size formula is not applicable to designs with time-to-event endpoints but the formula will be useful for practitioners while designing SMAR trials to compare adaptive treatment strategies. PMID:26412033

  3. Design, realization and structural testing of a compliant adaptable wing

    NASA Astrophysics Data System (ADS)

    Molinari, G.; Quack, M.; Arrieta, A. F.; Morari, M.; Ermanni, P.

    2015-10-01

    This paper presents the design, optimization, realization and testing of a novel wing morphing concept, based on distributed compliance structures, and actuated by piezoelectric elements. The adaptive wing features ribs with a selectively compliant inner structure, numerically optimized to achieve aerodynamically efficient shape changes while simultaneously withstanding aeroelastic loads. The static and dynamic aeroelastic behavior of the wing, and the effect of activating the actuators, is assessed by means of coupled 3D aerodynamic and structural simulations. To demonstrate the capabilities of the proposed morphing concept and optimization procedure, the wings of a model airplane are designed and manufactured according to the presented approach. The goal is to replace conventional ailerons, thus to achieve controllability in roll purely by morphing. The mechanical properties of the manufactured components are characterized experimentally, and used to create a refined and correlated finite element model. The overall stiffness, strength, and actuation capabilities are experimentally tested and successfully compared with the numerical prediction. To counteract the nonlinear hysteretic behavior of the piezoelectric actuators, a closed-loop controller is implemented, and its capability of accurately achieving the desired shape adaptation is evaluated experimentally. Using the correlated finite element model, the aeroelastic behavior of the manufactured wing is simulated, showing that the morphing concept can provide sufficient roll authority to allow controllability of the flight. The additional degrees of freedom offered by morphing can be also used to vary the plane lift coefficient, similarly to conventional flaps. The efficiency improvements offered by this technique are evaluated numerically, and compared to the performance of a rigid wing.

  4. Adaptive structures to enable ground test validation of precision structures

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Fanson, James F.; Chen, Gun-Shing; Kuo, Chin-Po

    1990-01-01

    The use of analytical models and ground-based experimental validation of precision space structures is addressed. The application of adaptive structures to such validation of precision space structures is addressed, with the focus on adaptive truss structures.

  5. Comparison of Item Targeting Strategies for Pass/Fail Computer Adaptive Tests.

    ERIC Educational Resources Information Center

    Bergstrom, Betty A.; Gershon, Richard

    The most useful method of item selection for making pass-fail decisions with a Computerized Adaptive Test (CAT) was studied. Medical technology students (n=86) took a computer adaptive test in which items were targeted to the ability of the examinee. The adaptive algorithm that selected items and estimated person measures used the Rasch model and…

  6. Role of microbial mats in the fossilization of soft tissues

    NASA Astrophysics Data System (ADS)

    Wilby, Philip R.; Briggs, Derek E. G.; Bernier, Paul; Gaillard, Christian

    1996-09-01

    It has been speculated that microbial mats are an important agent in the fossilization of soft tissues, particularly when apatite (Ca5[CO3, PO4]3[OH, F]) is involved. This has been tested by chemical analyses of the Jurassic limestones of Cerin, France, where phosphatized soft tissues are abundant and are associated with unequivocal microbial mats. The sedimentary distribution of P, K, and Fe following deposition was controlled by the presence of the mats. P concentrations in the mats may approach 2.5 times those elsewhere in the sediment. The highest P concentrations correlate with the occurrence of phosphatized soft tissues. This is the first analytical evidence to demonstrate a fundamental role for microbial mats in the preservation of soft-bodied fossils.

  7. Effects of preprocessing method on TVOC emission of car mat

    NASA Astrophysics Data System (ADS)

    Wang, Min; Jia, Li

    2013-02-01

    The effects of the mat preprocessing method on total volatile organic compounds (TVOC) emission of car mat are studied in this paper. An appropriate TVOC emission period for car mat is suggested. The emission factors for total volatile organic compounds from three kinds of new car mats are discussed. The car mats are preprocessed by washing, baking and ventilation. When car mats are preprocessed by washing, the TVOC emission for all samples tested are lower than that preprocessed in other methods. The TVOC emission is in stable situation for a minimum of 4 days. The TVOC emitted from some samples may exceed 2500μg/kg. But the TVOC emitted from washed Polyamide (PA) and wool mat is less than 2500μg/kg. The emission factors of total volatile organic compounds (TVOC) are experimentally investigated in the case of different preprocessing methods. The air temperature in environment chamber and the water temperature for washing are important factors influencing on emission of car mats.

  8. A Theoretical Study of Landing Mat Behavior

    DTIC Science & Technology

    1969-07-01

    the end joint expcrience6 progressive eeteriora- tion uc ’-o - con:r ;itaticn oL mat breaks ( rivet filure, cracking, an. curling) [l21. The weakened...Establishment, Suffield s-69-4 Oct 1969 Dutch Friction -Cone Penetrometer Exploration of Research Area at Field 5, Eglin APB, Florida *S-69-5 Apr 1969 Cracking...Tests. 66 12. Comparison of Performance for Single- Wheel Tests . . . . . . . . .. . 67 13. End Joint Moment Transfer Deficiency Based Upon Uniform

  9. A Modular Sensorized Mat for Monitoring Infant Posture

    PubMed Central

    Donati, Marco; Cecchi, Francesca; Bonaccorso, Filippo; Branciforte, Marco; Dario, Paolo; Vitiello, Nicola

    2014-01-01

    We present a novel sensorized mat for monitoring infant's posture through the measure of pressure maps. The pressure-sensitive mat is based on an optoelectronic technology developed in the last few years at Scuola Superiore Sant'Anna: a soft silicone skin cover, which constitutes the mat, participates in the transduction principle and provides the mat with compliance. The device has a modular structure (with a minimum of one and a maximum of six sub-modules, and a total surface area of about 1 m2) that enables dimensional adaptation of the pressure-sensitive area to different specific applications. The system consists of on-board electronics for data collection, pre-elaboration, and transmission to a remote computing unit for analysis and posture classification. In this work we present a complete description of the sensing apparatus along with its experimental characterization and validation with five healthy infants. PMID:24385029

  10. Elastic-plastic behavior of non-woven fibrous mats

    NASA Astrophysics Data System (ADS)

    Silberstein, Meredith N.; Pai, Chia-Ling; Rutledge, Gregory C.; Boyce, Mary C.

    2012-02-01

    Electrospinning is a novel method for creating non-woven polymer mats that have high surface area and high porosity. These attributes make them ideal candidates for multifunctional composites. Understanding the mechanical properties as a function of fiber properties and mat microstructure can aid in designing these composites. Further, a constitutive model which captures the membrane stress-strain behavior as a function of fiber properties and the geometry of the fibrous network would be a powerful design tool. Here, mats electrospun from amorphous polyamide are used as a model system. The elastic-plastic behavior of single fibers are obtained in tensile tests. Uniaxial monotonic and cyclic tensile tests are conducted on non-woven mats. The mat exhibits elastic-plastic stress-strain behavior. The transverse strain behavior provides important complementary data, showing a negligible initial Poisson's ratio followed by a transverse:axial strain ratio greater than -1:1 after an axial strain of 0.02. A triangulated framework has been developed to emulate the fibrous network structure of the mat. The micromechanically based model incorporates the elastic-plastic behavior of single fibers into a macroscopic membrane model of the mat. This representative volume element based model is shown to capture the uniaxial elastic-plastic response of the mat under monotonic and cyclic loading. The initial modulus and yield stress of the mat are governed by the fiber properties, the network geometry, and the network density. The transverse strain behavior is linked to discrete deformation mechanisms of the fibrous mat structure including fiber alignment, fiber bending, and network consolidation. The model is further validated in comparison to experiments under different constrained axial loading conditions and found to capture the constraint effect on stiffness, yield, post-yield hardening, and post-yield transverse strain behavior. Due to the direct connection between

  11. Compositions of constructed microbial mats

    DOEpatents

    Bender, Judith A.; Phillips, Peter C.

    1999-01-01

    Compositions and methods of use of constructed microbial mats, comprising cyanobacteria and purple autotrophic bacteria and an organic nutrient source, in a laminated structure, are described. The constructed microbial mat is used for bioremediation of different individual contaminants and for mixed or multiple contaminants, and for production of beneficial compositions and molecules.

  12. Validation of FRP Matting Requirements

    DTIC Science & Technology

    2016-08-01

    Civil Engineer Center to validate requirements for using Fiber Reinforced Polymer (FRP) matting as a foreign object debris cover when repairing damaged...19 2.8.2 Type B-3 polymer glue anchor...FOD cover matting solution, Fiber Reinforced Polymer (FRP), was identified as a potential replacement as the USAF airfield damage repair (ADR

  13. Variable-Length Computerized Adaptive Testing: Adaptation of the A-Stratified Strategy in Item Selection with Content Balancing

    ERIC Educational Resources Information Center

    Huo, Yan

    2009-01-01

    Variable-length computerized adaptive testing (CAT) can provide examinees with tailored test lengths. With the fixed standard error of measurement ("SEM") termination rule, variable-length CAT can achieve predetermined measurement precision by using relatively shorter tests compared to fixed-length CAT. To explore the application of…

  14. On the Issue of Item Selection in Computerized Adaptive Testing with Response Times

    ERIC Educational Resources Information Center

    Veldkamp, Bernard P.

    2016-01-01

    Many standardized tests are now administered via computer rather than paper-and-pencil format. The computer-based delivery mode brings with it certain advantages. One advantage is the ability to adapt the difficulty level of the test to the ability level of the test taker in what has been termed computerized adaptive testing (CAT). A second…

  15. HiMAT on lakebed after landing

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The HiMAT (Highly Maneuverable Aircraft Technology) subscale research vehicle, seen here after landing to conclude a research flight, was flown by the NASA Dryden Flight Research Center, Edwards, California, from mid 1979 to January 1983. The aircraft demonstrated advanced fighter technologies that have been used in the development of many modern high performance military aircraft. Two vehicles were used in the research program conducted jointly by NASA and the Air Force Flight Dynamics Laboratory, Wright-Patterson AFB, Ohio. The two vehicles, flown a total of 26 times, provided data on the use of composites, aeroelastic tailoring, close-coupled canards and winglets. They investigated the interaction of these then-new technologies upon each other. About one-half the size of a standard manned fighter and powered by a small jet engine, the HiMAT vehicles were launched from NASA's B-52 carrier aircraft at an altitude of about 45,000 feet. They were flown remotely by a NASA research pilot from a ground station with the aid of a television camera mounted in the HiMAT cockpits. Technologies tested on the HiMAT vehicles appearing later on other aircraft include the extensive use of composites common now on military and commercial aircraft; rear-mounted wing and forward canard configuration used very successfully on the X-29 research aircraft flown at Dryden; and winglets, now used on many private and commercial aircraft to lessen wingtip drag and enhance fuel savings.

  16. Computer-adaptive test to measure community reintegration of Veterans.

    PubMed

    Resnik, Linda; Tian, Feng; Ni, Pengsheng; Jette, Alan

    2012-01-01

    The Community Reintegration of Injured Service Members (CRIS) measure consists of three scales measuring extent of, perceived limitations in, and satisfaction with community reintegration. Length of the CRIS may be a barrier to its widespread use. Using item response theory (IRT) and computer-adaptive test (CAT) methodologies, this study developed and evaluated a briefer community reintegration measure called the CRIS-CAT. Large item banks for each CRIS scale were constructed. A convenience sample of 517 Veterans responded to all items. Exploratory and confirmatory factor analyses (CFAs) were used to identify the dimensionality within each domain, and IRT methods were used to calibrate items. Accuracy and precision of CATs of different lengths were compared with the full-item bank, and data were examined for differential item functioning (DIF). CFAs supported unidimensionality of scales. Acceptable item fit statistics were found for final models. Accuracy of 10-, 15-, 20-, and variable-item CATs for all three scales was 0.88 or above. CAT precision increased with number of items administered and decreased at the upper ranges of each scale. Three items exhibited moderate DIF by sex. The CRIS-CAT demonstrated promising measurement properties and is recommended for use in community reintegration assessment.

  17. Metagenomic analysis of stress genes in microbial mat communities from Antarctica and the High Arctic.

    PubMed

    Varin, Thibault; Lovejoy, Connie; Jungblut, Anne D; Vincent, Warwick F; Corbeil, Jacques

    2012-01-01

    Polar and alpine microbial communities experience a variety of environmental stresses, including perennial cold and freezing; however, knowledge of genomic responses to such conditions is still rudimentary. We analyzed the metagenomes of cyanobacterial mats from Arctic and Antarctic ice shelves, using high-throughput pyrosequencing to test the hypotheses that consortia from these extreme polar habitats were similar in terms of major phyla and subphyla and consequently in their potential responses to environmental stresses. Statistical comparisons of the protein-coding genes showed similarities between the mats from the two poles, with the majority of genes derived from Proteobacteria and Cyanobacteria; however, the relative proportions differed, with cyanobacterial genes more prevalent in the Antarctic mat metagenome. Other differences included a higher representation of Actinobacteria and Alphaproteobacteria in the Arctic metagenomes, which may reflect the greater access to diasporas from both adjacent ice-free lands and the open ocean. Genes coding for functional responses to environmental stress (exopolysaccharides, cold shock proteins, and membrane modifications) were found in all of the metagenomes. However, in keeping with the greater exposure of the Arctic to long-range pollutants, sequences assigned to copper homeostasis genes were statistically (30%) more abundant in the Arctic samples. In contrast, more reads matching the sigma B genes were identified in the Antarctic mat, likely reflecting the more severe osmotic stress during freeze-up of the Antarctic ponds. This study underscores the presence of diverse mechanisms of adaptation to cold and other stresses in polar mats, consistent with the proportional representation of major bacterial groups.

  18. Preliminary Report on a National Cross-Validation of the Computerized Adaptive Screening Test (CAST).

    ERIC Educational Resources Information Center

    Knapp, Deirdre J.; Pliske, Rebecca M.

    A study was conducted to validate the Army's Computerized Adaptive Screening Test (CAST), using data from 2,240 applicants from 60 army recruiting stations across the nation. CAST is a computer-assisted adaptive test used to predict performance on the Armed Forces Qualification Test (AFQT). AFQT scores are computed by adding four subtest scores of…

  19. Computerized Dynamic Adaptive Tests with Immediately Individualized Feedback for Primary School Mathematics Learning

    ERIC Educational Resources Information Center

    Wu, Huey-Min; Kuo, Bor-Chen; Wang, Su-Chen

    2017-01-01

    In this study, a computerized dynamic assessment test with both immediately individualized feedback and adaptively property was applied to Mathematics learning in primary school. For evaluating the effectiveness of the computerized dynamic adaptive test, the performances of three types of remedial instructions were compared by a pre-test/post-test…

  20. An Investigation on Computer-Adaptive Multistage Testing Panels for Multidimensional Assessment

    ERIC Educational Resources Information Center

    Wang, Xinrui

    2013-01-01

    The computer-adaptive multistage testing (ca-MST) has been developed as an alternative to computerized adaptive testing (CAT), and been increasingly adopted in large-scale assessments. Current research and practice only focus on ca-MST panels for credentialing purposes. The ca-MST test mode, therefore, is designed to gauge a single scale. The…

  1. Web-Based Adaptive Testing System (WATS) for Classifying Students Academic Ability

    ERIC Educational Resources Information Center

    Lee, Jaemu; Park, Sanghoon; Kim, Kwangho

    2012-01-01

    Computer Adaptive Testing (CAT) has been highlighted as a promising assessment method to fulfill two testing purposes: estimating student academic ability and classifying student academic level. In this paper, assessment for we introduced the Web-based Adaptive Testing System (WATS) developed to support a cost effective assessment for classifying…

  2. Evaluating Knowledge Structure-Based Adaptive Testing Algorithms and System Development

    ERIC Educational Resources Information Center

    Wu, Huey-Min; Kuo, Bor-Chen; Yang, Jinn-Min

    2012-01-01

    In recent years, many computerized test systems have been developed for diagnosing students' learning profiles. Nevertheless, it remains a challenging issue to find an adaptive testing algorithm to both shorten testing time and precisely diagnose the knowledge status of students. In order to find a suitable algorithm, four adaptive testing…

  3. USING AN ADAPTER TO PERFORM THE CHALFANT-STYLE CONTAINMENT VESSEL PERIODIC MAINTENANCE LEAK RATE TEST

    SciTech Connect

    Loftin, B.; Abramczyk, G.; Trapp, D.

    2011-06-03

    Recently the Packaging Technology and Pressurized Systems (PT&PS) organization at the Savannah River National Laboratory was asked to develop an adapter for performing the leak-rate test of a Chalfant-style containment vessel. The PT&PS organization collaborated with designers at the Department of Energy's Pantex Plant to develop the adapter currently in use for performing the leak-rate testing on the containment vessels. This paper will give the history of leak-rate testing of the Chalfant-style containment vessels, discuss the design concept for the adapter, give an overview of the design, and will present results of the testing done using the adapter.

  4. Gelatin blending and sonication of chitosan nanofiber mats produce synergistic effects on hemostatic functions.

    PubMed

    Gu, Bon Kang; Park, Sang Jun; Kim, Min Sup; Lee, Yong Jin; Kim, Jong-Il; Kim, Chun-Ho

    2016-01-01

    To improve the hemostatic function of chitosan nanofiber mats, we studied the synergetic effects of gelatin blending and porosity control. Gelatin-blended-chitosan (Chi-Gel) nanofiber mats were evaluated with respect to surface morphology, mechanical properties and wettability, and functionally tested in a blood clotting study. The blood clotting efficiency of Chi-Gel nanofiber mats using rabbit whole blood in vitro was superior to that of chitosan nanofibers. Moreover, Chi-Gel nanofiber mats with enlarged porosity, produced by ultra-sonication, showed improved blood clotting efficiency, cell viability and cell infiltration compared with non-sonicated Chi-Gel nanofiber mats. Field-emission scanning electron microscopy revealed a richer density of platelets on sonicated nanofiber mats than on non-sonicated nanofiber mats after 3 min of blood clotting. The proliferation of human dermal fibroblast cells on sonicated Chi-Gel nanofiber mats using the DNA assay was higher than that on non-sonicated chitosan nanofiber mats after 7 days of culture. Confocal z-stack images showed that sonicated Chi-Gel nanofiber mats with high porosity supported active cell migration and infiltration into the 3-dimensional nanofiber mats. These results suggest that hydrophilic gelatin blending and sonication of chitosan nanofiber mats yields synergistic effects that not only improve hemostatic function but also promote wound repair.

  5. Parameter testing for lattice filter based adaptive modal control systems

    NASA Technical Reports Server (NTRS)

    Sundararajan, N.; Williams, J. P.; Montgomery, R. C.

    1983-01-01

    For Large Space Structures (LSS), an adaptive control system is highly desirable. The present investigation is concerned with an 'indirect' adaptive control scheme wherein the system order, mode shapes, and modal amplitudes are estimated on-line using an identification scheme based on recursive, least-squares, lattice filters. Using the identified model parameters, a modal control law based on a pole-placement scheme with the objective of vibration suppression is employed. A method is presented for closed loop adaptive control of a flexible free-free beam. The adaptive control scheme consists of a two stage identification scheme working in series and a modal pole placement control scheme. The main conclusion from the current study is that the identified parameters cannot be directly used for controller design purposes.

  6. Manganese Influences Carbonate Precipitation in a Laminated Microbial Mat

    NASA Astrophysics Data System (ADS)

    Krusor, M.; Grim, S. L.; Wilmeth, D.; Johnson, H.; Berelson, W.; Stevenson, B. S.; Stamps, B. W.; Corsetti, F. A.; Spear, J. R.

    2015-12-01

    Investigating mineralization within modern microbial mats informs our interpretation of ancient microbialites and the mineralization process. Microbial mats in Little Hot Creek (LHC), California contain 4 distinct layers with different microbiota. Each layer of the mat is supersaturated with regard to calcium carbonate (CaCO3), which increases with depth. Total organic carbon decreases with depth through the mat. We used 13C-labeled bicarbonate incubations of each mat layer to calculate growth rates of organic carbon and CaCO3 within the mat. Incubations were also amended with Mn or Mg to test their effect on rates of CaCO3 and organic carbon formation. The Mn-amended top layer increased CaCO3 precipitation and organic carbon growth. Mn increased organic carbon production in the lowest layer to a lesser extent, but not growth of CaCO3. Mn addition had no effect on growth rates in the two intervening layers. Mg amendment stimulated only organic carbon formation in the top layer, with little to no effect on the lower layers or overall CaCO3 formation. We attribute the elevated CaCO3 precipitation noted after Mn addition to increased oxygenic photosynthetic activity. Oxygenic photosynthesis requires Mn as an enzyme cofactor and promotes carbonate precipitation. We propose that the phototrophic community was responsible for most of the CaCO3 precipitation in the upper layer. Phototrophs gradually moved upwards for optimal access to sunlight, and as the mat grew, "tenant" microorganisms inhabited the lower carbonate layers while the "builders" remained on top. The relatively constant percentages of inorganic carbon below the top layer combined with observed minimal CaCO3 precipitation under laboratory conditions suggest that additional research into potential metabolisms that impact carbonate formation would be informative. These results improve our understanding of the linkages between microbial metabolisms, carbonate precipitation in microbial mats, and the potential

  7. Adaptive resolution simulation of liquid para-hydrogen: testing the robustness of the quantum-classical adaptive coupling.

    PubMed

    Poma, A B; Delle Site, L

    2011-06-14

    Adaptive resolution simulations for classical systems are currently made within a reasonably consistent theoretical framework. Recently we have extended this approach to the quantum-classical coupling by mapping the quantum nature of an atom onto a classical polymer ring representation within the path integral approach [Poma & Delle Site, Phys. Rev. Lett., 2010, 104, 250201]. In this way the process of interfacing adaptively a quantum representation to a classical one corresponds to the problem of interfacing two regions with a different number of effective "classical" degrees of freedom; thus the classical formulation of the adaptive algorithm applies straightforwardly to the quantum-classical problem. In this work we show the robustness of such an approach for a liquid of para-hydrogen at low temperature. This system represents a highly challenging conceptual and technical test for the adaptive approach due to the extreme thermodynamical conditions where quantum effects play a central role.

  8. A Model for Optimal Constrained Adaptive Testing. Law School Admission Council Computerized Testing Report. LSAC Research Report Series.

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Reese, Lynda M.

    A model for constrained computerized adaptive testing is proposed in which the information on the test at the ability estimate is maximized subject to a large variety of possible constraints on the contents of the test. At each item-selection step, a full test is first assembled to have maximum information at the current ability estimate fixing…

  9. Optimal Stratification of Item Pools in a-Stratified Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Chang, Hua-Hua; van der Linden, Wim J.

    2003-01-01

    Developed a method based on 0-1 linear programming to stratify an item pool optimally for use in alpha-stratified adaptive testing. Applied the method to a previous item pool from the computerized adaptive test of the Graduate Record Examinations. Results show the new method performs well in practical situations. (SLD)

  10. Development and Evaluation of a Confidence-Weighting Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Yen, Yung-Chin; Ho, Rong-Guey; Chen, Li-Ju; Chou, Kun-Yi; Chen, Yan-Lin

    2010-01-01

    The purpose of this study was to examine whether the efficiency, precision, and validity of computerized adaptive testing (CAT) could be improved by assessing confidence differences in knowledge that examinees possessed. We proposed a novel polytomous CAT model called the confidence-weighting computerized adaptive testing (CWCAT), which combined a…

  11. A Mixture Rasch Model-Based Computerized Adaptive Test for Latent Class Identification

    ERIC Educational Resources Information Center

    Jiao, Hong; Macready, George; Liu, Junhui; Cho, Youngmi

    2012-01-01

    This study explored a computerized adaptive test delivery algorithm for latent class identification based on the mixture Rasch model. Four item selection methods based on the Kullback-Leibler (KL) information were proposed and compared with the reversed and the adaptive KL information under simulated testing conditions. When item separation was…

  12. A Durbin-Watson serial correlation test for ARX processes via excited adaptive tracking

    NASA Astrophysics Data System (ADS)

    Bercu, Bernard; Portier, Bruno; Vazquez, Victor

    2015-12-01

    We propose a new statistical test for the residual autocorrelation in ARX adaptive tracking. The introduction of a persistent excitation in the adaptive tracking control allows us to build a bilateral statistical test based on the well-known Durbin-Watson statistic. We establish the almost sure convergence and the asymptotic normality for the Durbin-Watson statistic leading to a powerful serial correlation test. Numerical experiments illustrate the good performances of our statistical test procedure.

  13. Capillography of Mats of Nanofibers

    NASA Technical Reports Server (NTRS)

    Noca, Flavio; Sansom, Elijah; Zhou, Jijie; Gharib, Mory

    2008-01-01

    Capillography (from the Latin capillus, 'hair', and the Greek graphein, to write ) is a recently conceived technique for forming mats of nanofibers into useful patterns. The concept was inspired by experiments on carpetlike mats of multiwalled carbon nanotubes. Capillography may have the potential to be a less-expensive, less-time-consuming alternative to electron-beam lithography as a means of nanoscale patterning for the fabrication of small devices and instruments. In capillography, one exploits the lateral capillary forces exerted on small objects that pierce the surface of a liquid. If the small objects are identical, then the forces are always attractive. Two examples of the effects of such forces are the agglomeration of small particles floating on the surface of a pond and the drawing together of hairs of a wet paintbrush upon removal of the brush from water. Because nanoscale objects brought into contact remain stuck together indefinitely due to Van der Waals forces, patterns formed by capillography remain even upon removal of the liquid. For the experiments on the mats of carbon nanotubes, a surfactant solution capable of wetting carbon nanotubes (which are ultra-hydrophobic) was prepared. The mats were wetted with the solution, then dried. Once the mats were dry, it was found that the nanotubes had become ordered into various patterns, including nestlike indentations, trenches, and various combinations thereof. It may be possible to exploit such ordering effects through controlled wetting and drying of designated portions of mats of carbon nanotubes (and, perhaps, mats of nanofibers of other materials) to obtain patterns similar to those heretofore formed by use of electron-beam lithography. For making patterns that include nestlike indentations, it has been conjectured that it could be possible to control the nesting processes by use of electrostatic fields. Further research is needed to understand the physics of the patterning processes in order to

  14. A Testlet Assembly Design for Adaptive Multistage Tests

    ERIC Educational Resources Information Center

    Luecht, Richard; Brumfield, Terry; Breithaupt, Krista

    2006-01-01

    This article describes multistage tests and some practical test development considerations related to the design and implementation of a multistage test, using the Uniform CPA (certified public accountant) Examination as a case study. The article further discusses the use of automated test assembly procedures in an operational context to produce…

  15. A field operational test on valve-regulated lead-acid absorbent-glass-mat batteries in micro-hybrid electric vehicles. Part II. Results based on multiple regression analysis and tear-down analysis

    NASA Astrophysics Data System (ADS)

    Schaeck, S.; Karspeck, T.; Ott, C.; Weirather-Koestner, D.; Stoermer, A. O.

    2011-03-01

    In the first part of this work [1] a field operational test (FOT) on micro-HEVs (hybrid electric vehicles) and conventional vehicles was introduced. Valve-regulated lead-acid (VRLA) batteries in absorbent glass mat (AGM) technology and flooded batteries were applied. The FOT data were analyzed by kernel density estimation. In this publication multiple regression analysis is applied to the same data. Square regression models without interdependencies are used. Hereby, capacity loss serves as dependent parameter and several battery-related and vehicle-related parameters as independent variables. Battery temperature is found to be the most critical parameter. It is proven that flooded batteries operated in the conventional power system (CPS) degrade faster than VRLA-AGM batteries in the micro-hybrid power system (MHPS). A smaller number of FOT batteries were applied in a vehicle-assigned test design where the test battery is repeatedly mounted in a unique test vehicle. Thus, vehicle category and specific driving profiles can be taken into account in multiple regression. Both parameters have only secondary influence on battery degradation, instead, extended vehicle rest time linked to low mileage performance is more serious. A tear-down analysis was accomplished for selected VRLA-AGM batteries operated in the MHPS. Clear indications are found that pSoC-operation with periodically fully charging the battery (refresh charging) does not result in sulphation of the negative electrode. Instead, the batteries show corrosion of the positive grids and weak adhesion of the positive active mass.

  16. Multidimensional Computerized Adaptive Scholastic Aptitude Test Program Used for Grade 9 Students under Different Reviewing Test Conditions

    ERIC Educational Resources Information Center

    Khunkrai, Naruemon; Sawangboon, Tatsirin; Ketchatturat, Jatuphum

    2015-01-01

    The aim of this research is to study the accurate prediction of comparing test information and evaluation result by multidimensional computerized adaptive scholastic aptitude test program used for grade 9 students under different reviewing test conditions. Grade 9 students of the Secondary Educational Service Area Office in the North-east of…

  17. Computerized Adaptive Spanish Placement Test. Final Performance Report.

    ERIC Educational Resources Information Center

    Larson, Jerry W.

    A study at Brigham Young University (Utah) investigated the feasibility of computer-assisted language placement testing in higher education. Benefits and problems of this approach for test administration, individualization of item selection, and recordkeeping were examined. Four steps were followed in production of a test for Spanish placement:…

  18. Using Out-of-Level Items in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Wei, Hua; Lin, Jie

    2015-01-01

    Out-of-level testing refers to the practice of assessing a student with a test that is intended for students at a higher or lower grade level. Although the appropriateness of out-of-level testing for accountability purposes has been questioned by educators and policymakers, incorporating out-of-level items in formative assessments for accurate…

  19. Adapting the Critical Thinking Assessment Test for Palestinian Universities

    ERIC Educational Resources Information Center

    Basha, Sami; Drane, Denise; Light, Gregory

    2016-01-01

    Critical thinking is a key learning outcome for Palestinian students. However, there are no validated critical thinking tests in Arabic. Suitability of the US developed Critical Thinking Assessment Test (CAT) for use in Palestine was assessed. The test was piloted with university students in English (n = 30) and 4 questions were piloted in Arabic…

  20. A Comparison of Item-Selection Methods for Adaptive Tests with Content Constraints

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2005-01-01

    In test assembly, a fundamental difference exists between algorithms that select a test sequentially or simultaneously. Sequential assembly allows us to optimize an objective function at the examinee's ability estimate, such as the test information function in computerized adaptive testing. But it leads to the non-trivial problem of how to realize…

  1. Photosynthate Partitioning and Fermentation in Hot Spring Microbial Mat Communities

    PubMed Central

    Nold, S. C.; Ward, D. M.

    1996-01-01

    Patterns of (sup14)CO(inf2) incorporation into molecular components of the thermophilic cyanobacterial mat communities inhabiting hot springs located in Yellowstone National Park and Synechococcus sp. strain C1 were investigated. Exponentially growing Synechococcus sp. strain C1 partitioned the majority of incorporated (sup14)CO(inf2) into protein, low-molecular-weight metabolites, and lipid fractions (45, 22, and 18% of total incorporated carbon, respectively). In contrast, mat cores from various hot springs predominantly accumulated polyglucose during periods of illumination (between 77 and 85% of total incorporated (sup14)CO(inf2)). Although photosynthetically active, mat photoautotrophs do not appear to be rapidly growing, since we also detected only limited synthesis of macromolecules associated with growth (i.e., protein and rRNA). To test the hypothesis that polysaccharide reserves are fermented in situ under the dark anaerobic conditions cyanobacterial mats experience at night, mat cores were prelabeled with (sup14)CO(inf2) under illuminated conditions and then transferred to dark anaerobic conditions. Radiolabel in the polysaccharide fraction decreased by 74.7% after 12 h, of which 58.5% was recovered as radiolabeled acetate, CO(inf2), and propionate. These results indicate tightly coupled carbon fixation and fermentative processes and the potential for significant transfer of carbon from primary producers to heterotrophic members of these cyanobacterial mat communities. PMID:16535472

  2. Mechanical behavior of ultralong multiwalled carbon nanotube mats

    NASA Astrophysics Data System (ADS)

    Deck, Christian P.; Flowers, Jason; McKee, Gregg S. B.; Vecchio, Kenneth

    2007-01-01

    Carbon nanotubes (CNTs) have been a subject of great interest partially due to their potential for exceptional material properties. Improvements in synthesis methods have facilitated the production of ultralong CNT mats, with lengths in the millimeter range. The increased length of these ultralong mats has, in return, opened the way to greater flexibility to probe their mechanical response. In this work, mats of dense, well-aligned, multiwalled carbon nanotubes were grown with a vapor-phase chemical vapor deposition technique using ferrocene and benzene as reactants, and subsequently tested in both tension and compression using two methods, in a thermomechanical analyzer and in situ inside a scanning electron microscope. In compression, measured stiffness was very low, due to buckling of the nanotubes. In tension, the nanotube mats behaved considerably stiffer; however, they were still more compliant than expected for nanotubes (˜1TPa). Analysis of both the growth method used and the nanotube mat fracture surface suggests that the mats grown in this method are not composed of continuous nanotubes and their strengths actually closely match those of woven nanotube yarns and ropes.

  3. Some Considerations for Eliminating Biases in Ability Estimation in Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Samejima, Fumiko

    Item response theory (IRT) has been adapted as the theoretical foundation of computerized adaptive testing (CAT) for several decades. In applying IRT to CAT, there are certain considerations that are essential, and yet tend to be neglected. These essential issues are addressed in this paper, and then several ways of eliminating noise and bias in…

  4. Qualitative Examination of Children's Naming Skills through Test Adaptations.

    ERIC Educational Resources Information Center

    Fried-Oken, Melanie

    1987-01-01

    The Double Administration Naming Technique assists clinicians in obtaining qualitative information about a client's visual confrontation naming skills through administration of a standard naming test; readministration of the same test; identification of single and double errors; cuing for double naming errors; and qualitative analysis of naming…

  5. L(sub 1) Adaptive Control Design for NASA AirSTAR Flight Test Vehicle

    NASA Technical Reports Server (NTRS)

    Gregory, Irene M.; Cao, Chengyu; Hovakimyan, Naira; Zou, Xiaotian

    2009-01-01

    In this paper we present a new L(sub 1) adaptive control architecture that directly compensates for matched as well as unmatched system uncertainty. To evaluate the L(sub 1) adaptive controller, we take advantage of the flexible research environment with rapid prototyping and testing of control laws in the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. We apply the L(sub 1) adaptive control laws to the subscale turbine powered Generic Transport Model. The presented results are from a full nonlinear simulation of the Generic Transport Model and some preliminary pilot evaluations of the L(sub 1) adaptive control law.

  6. Adaptive antenna arrays for satellite communications: Design and testing

    NASA Technical Reports Server (NTRS)

    Gupta, I. J.; Swarner, W. G.; Walton, E. K.

    1985-01-01

    When two separate antennas are used with each feedback loop to decorrelate noise, the antennas should be located such that the phase of the interfering signal in the two antennas is the same while the noise in them is uncorrelated. Thus, the antenna patterns and spatial distribution of the auxiliary antennas are quite important and should be carefully selected. The selection and spatial distribution of auxiliary elements is discussed when the main antenna is a center fed reflector antenna. It is shown that offset feeds of the reflector antenna can be used as auxiliary elements of an adaptive array to suppress weak interfering signals. An experimental system is designed to verify the theoretical analysis. The details of the experimental systems are presented.

  7. Some Tests For Adaptative Observations In Atmospheric Chemistry

    NASA Astrophysics Data System (ADS)

    Quélo, D.; Michelangeli, P.-A.; Sportisse, B.

    Air pollution forecast requires the coupling of models with data through data assimi- lation. A key question is related to the choice of observations (apart from technical require- ments). One wants to choose in a judicious way the species to observe, in which loca- tions and at which moments. The appropriate strategies are related to the techniques of "targeting" and "adaptative observations". We will investigate these techniques on a simplified model. The first part reports the influence of the slow-fast behaviour of atmospheric chem- istry. The second part presents the use of singular vectors and second-order adjoint techniques in order to determine the "optimal" choice of observations. This project is led in the framework of the INRIA Cooperative Research Action CO- MODE (COupling MOdels and Data in Environment).

  8. ON TEACHING ARCELLANA'S "THE MATS".

    ERIC Educational Resources Information Center

    ANDERSON, TOMMY R.

    FRANCISCO ARCELLANA'S "THE MATS," LIKE ANY WELL-CONSTRUCTED SHORT STORY, CAN SERVE AS AN IMPORTANT TEACHING DEVICE IN GUIDING STUDENTS, ESPECIALLY THOSE LEARNING ENGLISH AS A SECOND LANGUAGE, TO READ WITH UNDERSTANDING AND APPRECIATION, THE TECHNIQUES OF CONVERTING VERBALS BACK INTO VERBS, REPLACING ALL PRONOUNS WITH THEIR ANTECEDENTS IN PARALLEL…

  9. Stiffness of compressed fiber mats

    NASA Astrophysics Data System (ADS)

    Åström, J. A.; Mäkinen, J. P.; Hirvonen, H.; Timonen, J.

    2000-11-01

    We investigate, using an analytical and a numerical model, the in-plane stiffness of fiber mats. A mat is modeled by randomly depositing thin linear-elastic fibers on top of each other under the influence of an external pressure. The external pressure has the effect of bending the fibers over each other. The fibers are assumed rigidly bonded at contacts. For a low external pressure the stiffness of the mat deviates from that of its two-dimensional projection only by a geometrical factor, and the effective Poisson contraction is close to zero. For higher pressures, stiffness is governed by two competing effects and a maximum appears in the stiffness. The effective Poisson ratio is clearly negative in this range. An approximative analytical description is developed for the stiffness of mats formed under low external pressure. The stiffness is given as a function of only a few parameters: the degree of bonding, the dimensions of the fibers, the elastic constants of the fiber material, and the density of fibers.

  10. Sparse Coding for Alpha Matting.

    PubMed

    Johnson, Jubin; Varnousfaderani, Ehsan Shahrian; Cholakkal, Hisham; Rajan, Deepu

    2016-07-01

    Existing color sampling-based alpha matting methods use the compositing equation to estimate alpha at a pixel from the pairs of foreground ( F ) and background ( B ) samples. The quality of the matte depends on the selected ( F,B ) pairs. In this paper, the matting problem is reinterpreted as a sparse coding of pixel features, wherein the sum of the codes gives the estimate of the alpha matte from a set of unpaired F and B samples. A non-parametric probabilistic segmentation provides a certainty measure on the pixel belonging to foreground or background, based on which a dictionary is formed for use in sparse coding. By removing the restriction to conform to ( F,B ) pairs, this method allows for better alpha estimation from multiple F and B samples. The same framework is extended to videos, where the requirement of temporal coherence is handled effectively. Here, the dictionary is formed by samples from multiple frames. A multi-frame graph model, as opposed to a single image as for image matting, is proposed that can be solved efficiently in closed form. Quantitative and qualitative evaluations on a benchmark dataset are provided to show that the proposed method outperforms the current stateoftheart in image and video matting.

  11. Sparse Coding for Alpha Matting.

    PubMed

    Johnson, Jubin; Varnousfaderani, Ehsan; Cholakkal, Hisham; Rajan, Deepu

    2016-04-21

    Existing color sampling based alpha matting methods use the compositing equation to estimate alpha at a pixel from pairs of foreground (F) and background (B) samples. The quality of the matte depends on the selected (F,B) pairs. In this paper, the matting problem is reinterpreted as a sparse coding of pixel features, wherein the sum of the codes gives the estimate of the alpha matte from a set of unpaired F and B samples. A non-parametric probabilistic segmentation provides a certainty measure on the pixel belonging to foreground or background, based on which a dictionary is formed for use in sparse coding. By removing the restriction to conform to (F,B) pairs, this method allows for better alpha estimation from multiple F and B samples. The same framework is extended to videos, where the requirement of temporal coherence is handled effectively. Here, the dictionary is formed by samples from multiple frames. A multi-frame graph model, as opposed to a single image as for image matting, is proposed that can be solved efficiently in closed form. Quantitative and qualitative evaluations on a benchmark dataset are provided to show that the proposed method outperforms current state-of-the-art in image and video matting.

  12. Adaptation.

    PubMed

    Broom, Donald M

    2006-01-01

    The term adaptation is used in biology in three different ways. It may refer to changes which occur at the cell and organ level, or at the individual level, or at the level of gene action and evolutionary processes. Adaptation by cells, especially nerve cells helps in: communication within the body, the distinguishing of stimuli, the avoidance of overload and the conservation of energy. The time course and complexity of these mechanisms varies. Adaptive characters of organisms, including adaptive behaviours, increase fitness so this adaptation is evolutionary. The major part of this paper concerns adaptation by individuals and its relationships to welfare. In complex animals, feed forward control is widely used. Individuals predict problems and adapt by acting before the environmental effect is substantial. Much of adaptation involves brain control and animals have a set of needs, located in the brain and acting largely via motivational mechanisms, to regulate life. Needs may be for resources but are also for actions and stimuli which are part of the mechanism which has evolved to obtain the resources. Hence pigs do not just need food but need to be able to carry out actions like rooting in earth or manipulating materials which are part of foraging behaviour. The welfare of an individual is its state as regards its attempts to cope with its environment. This state includes various adaptive mechanisms including feelings and those which cope with disease. The part of welfare which is concerned with coping with pathology is health. Disease, which implies some significant effect of pathology, always results in poor welfare. Welfare varies over a range from very good, when adaptation is effective and there are feelings of pleasure or contentment, to very poor. A key point concerning the concept of individual adaptation in relation to welfare is that welfare may be good or poor while adaptation is occurring. Some adaptation is very easy and energetically cheap and

  13. The Childhood Autism Spectrum Test (CAST): Spanish adaptation and validation.

    PubMed

    Morales-Hidalgo, Paula; Roigé-Castellví, Joana; Vigil-Colet, Andreu; Canals Sans, Josefa

    2017-04-06

    The Childhood Autism Spectrum Test (CAST; Scott et al. Autism 2002; 6:9-31) has proved to be a good test for screening autism spectrum disorders (ASD) and social communication problems. This study provides evidence on the statistical properties of the CAST, specifically its validity, factorial structure and discriminative capacity as an ASD screening test, in a Spanish sample of 4-12 year-old children from community and clinical settings. The study concludes that the test was valid and reliable for ASD screening in Spanish clinical and community populations and allowed us to create a new abbreviated version. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

  14. Test techniques: A survey paper on cryogenic tunnels, adaptive wall test sections, and magnetic suspension and balance systems

    NASA Technical Reports Server (NTRS)

    Kilgore, Robert A.; Dress, David A.; Wolf, Stephen W. D.; Britcher, Colin P.

    1989-01-01

    The ability to get good experimental data in wind tunnels is often compromised by things seemingly beyond our control. Inadequate Reynolds number, wall interference, and support interference are three of the major problems in wind tunnel testing. Techniques for solving these problems are available. Cryogenic wind tunnels solve the problem of low Reynolds number. Adaptive wall test sections can go a long way toward eliminating wall interference. A magnetic suspension and balance system (MSBS) completely eliminates support interference. Cryogenic tunnels, adaptive wall test sections, and MSBS are surveyed. A brief historical overview is given and the present state of development and application in each area is described.

  15. Dynamics of archaea at fine spatial scales in Shark Bay mat microbiomes

    PubMed Central

    Wong, Hon Lun; Visscher, Pieter T.; White III, Richard Allen; Smith, Daniela-Lee; Patterson, Molly M.; Burns, Brendan P.

    2017-01-01

    The role of archaea in microbial mats is poorly understood. Delineating the spatial distribution of archaea with mat depth will enable resolution of putative niches in these systems. In the present study, high throughput amplicon sequencing was undertaken in conjunction with analysis of key biogeochemical properties of two mats (smooth and pustular) from Shark Bay, Australia. One-way analysis of similarity tests indicated the archaeal community structures of smooth and pustular mats were significantly different (global R = 1, p = 0.1%). Smooth mats possessed higher archaeal diversity, dominated by Parvarchaeota. The methanogenic community in smooth mats was dominated by hydrogenotrophic Methanomicrobiales, as well as methylotrophic Methanosarcinales, Methanococcales, Methanobacteriales and Methanomassiliicoccaceae. Pustular mats were enriched with Halobacteria and Parvarchaeota. Key metabolisms (bacterial and archaeal) were measured, and the rates of oxygen production/consumption and sulfate reduction were up to four times higher in smooth than in pustular mats. Methane production peaked in the oxic layers and was up to seven-fold higher in smooth than pustular mats. The finding of an abundance of anaerobic methanogens enriched at the surface where oxygen levels were highest, coupled with peak methane production in the oxic zone, suggests putative surface anoxic niches in these microbial mats.

  16. Increasing Testing Efficiency through the Development of an IT-Based Adaptive Testing Tool for Competency Measurement

    ERIC Educational Resources Information Center

    Kleinhans, Janne; Schumann, Matthias

    2015-01-01

    Purpose: This paper investigates the potential of computerized adaptive testing for CMs to reduce test time. In the context of education and training, competency measurement (CM) is a central challenge in competency management. For complex CMs, a compromise must be addressed between the time available and the quality of the measurements.…

  17. Computer Adaptive Language Tests (CALT) Offer a Great Potential for Functional Testing. Yet Why Don't They?

    ERIC Educational Resources Information Center

    Meunier, Lydie E.

    1994-01-01

    Computer adaptive language testing (CALT) offers a variety of advantages; however, since CALT cannot test the multidimensional nature of language, it does not assess communicative/functional language. This article proposes to replace multiple choice and cloze formats and to apply CALT to live-action simulations. (18 references) (LB)

  18. A-Stratified Computerized Adaptive Testing with Unequal Item Exposure across Strata.

    ERIC Educational Resources Information Center

    Deng, Hui; Chang, Hua-Hua

    The purpose of this study was to compare a proposed revised a-stratified, or alpha-stratified, USTR method of test item selection with the original alpha-stratified multistage computerized adaptive testing approach (STR) and the use of maximum Fisher information (FSH) with respect to test efficiency and item pool usage using simulated computerized…

  19. Self Adapted Testing as Formative Assessment: Effects of Feedback and Scoring on Engagement and Performance

    ERIC Educational Resources Information Center

    Arieli-Attali, Meirav

    2016-01-01

    This dissertation investigated the feasibility of self-adapted testing (SAT) as a formative assessment tool with the focus on learning. Under two different orientation goals--to excel on a test (performance goal) or to learn from the test (learning goal)--I examined the effect of different scoring rules provided as interactive feedback, on test…

  20. Adaptation of a Vocabulary Test from British Sign Language to American Sign Language

    ERIC Educational Resources Information Center

    Mann, Wolfgang; Roy, Penny; Morgan, Gary

    2016-01-01

    This study describes the adaptation process of a vocabulary knowledge test for British Sign Language (BSL) into American Sign Language (ASL) and presents results from the first round of pilot testing with 20 deaf native ASL signers. The web-based test assesses the strength of deaf children's vocabulary knowledge by means of different mappings of…

  1. EXSPRT: An Expert Systems Approach to Computer-Based Adaptive Testing.

    ERIC Educational Resources Information Center

    Frick, Theodore W.; And Others

    Expert systems can be used to aid decision making. A computerized adaptive test (CAT) is one kind of expert system, although it is not commonly recognized as such. A new approach, termed EXSPRT, was devised that combines expert systems reasoning and sequential probability ratio test stopping rules. EXSPRT-R uses random selection of test items,…

  2. The Influence of Item Calibration Error on Variable-Length Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Patton, Jeffrey M.; Cheng, Ying; Yuan, Ke-Hai; Diao, Qi

    2013-01-01

    Variable-length computerized adaptive testing (VL-CAT) allows both items and test length to be "tailored" to examinees, thereby achieving the measurement goal (e.g., scoring precision or classification) with as few items as possible. Several popular test termination rules depend on the standard error of the ability estimate, which in turn depends…

  3. Hybrid Computerized Adaptive Testing: From Group Sequential Design to Fully Sequential Design

    ERIC Educational Resources Information Center

    Wang, Shiyu; Lin, Haiyan; Chang, Hua-Hua; Douglas, Jeff

    2016-01-01

    Computerized adaptive testing (CAT) and multistage testing (MST) have become two of the most popular modes in large-scale computer-based sequential testing. Though most designs of CAT and MST exhibit strength and weakness in recent large-scale implementations, there is no simple answer to the question of which design is better because different…

  4. An Efficiency Balanced Information Criterion for Item Selection in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Han, Kyung T.

    2012-01-01

    Successful administration of computerized adaptive testing (CAT) programs in educational settings requires that test security and item exposure control issues be taken seriously. Developing an item selection algorithm that strikes the right balance between test precision and level of item pool utilization is the key to successful implementation…

  5. Computer-controlled noise adaption for acoustical test facilities

    NASA Astrophysics Data System (ADS)

    Wedig, W. V.; Ams, A.

    1990-09-01

    For acoustical noise tests of elastic structures, statistically representative signals generated from white noise by means of spectrum shapers and band pass filters are needed. Subsequently, these signals are amplified and transformed into physical test noise by acoustical sirens. A mathematical model of the entire system based on measurements of frequency transfer functions in order to predict an optimal amplitude modulation of the spectrum shaper is presented. The prediction is performed by means of a nonlinear optimization procedure which iterates the tuning parameters of the shaper with respect to the stored frequency data of the entire system.

  6. The full spectrum of climate change adaptation: testing an analytical framework in Tyrolean mountain agriculture (Austria).

    PubMed

    Grüneis, Heidelinde; Penker, Marianne; Höferl, Karl-Michael

    2016-01-01

    Our scientific view on climate change adaptation (CCA) is unsatisfying in many ways: It is often dominated by a modernistic perspective of planned pro-active adaptation, with a selective focus on measures directly responding to climate change impacts and thus it is far from real-life conditions of those who are actually affected by climate change. Farmers have to simultaneously adapt to multiple changes. Therefore, also empirical climate change adaptation research needs a more integrative perspective on real-life climate change adaptations. This also has to consider "hidden" adaptations, which are not explicitly and directly motivated by CCA but actually contribute to the sector's adaptability to climate change. The aim of the present study is to develop and test an analytic framework that contributes to a broader understanding of CCA and to bridge the gap between scientific expertise and practical action. The framework distinguishes three types of CCA according to their climate related motivations: explicit adaptations, multi-purpose adaptations, and hidden adaptations. Although agriculture is among the sectors that are most affected by climate change, results from the case study of Tyrolean mountain agriculture show that climate change is ranked behind other more pressing "real-life-challenges" such as changing agricultural policies or market conditions. We identified numerous hidden adaptations which make a valuable contribution when dealing with climate change impacts. We conclude that these hidden adaptations have not only to be considered to get an integrative und more realistic view on CCA; they also provide a great opportunity for linking adaptation strategies to farmers' realities.

  7. Investigating Item Exposure Control Methods in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    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. Testing Adaptive Toolbox Models: A Bayesian Hierarchical Approach

    ERIC Educational Resources Information Center

    Scheibehenne, Benjamin; Rieskamp, Jorg; Wagenmakers, Eric-Jan

    2013-01-01

    Many theories of human cognition postulate that people are equipped with a repertoire of strategies to solve the tasks they face. This theoretical framework of a cognitive toolbox provides a plausible account of intra- and interindividual differences in human behavior. Unfortunately, it is often unclear how to rigorously test the toolbox…

  9. Traveling with Cognitive Tests: Testing the Validity of a KABC-II Adaptation in India

    ERIC Educational Resources Information Center

    Malda, Maike; van de Vijver, Fons J. R.; Srinivasan, Krishnamachari; Transler, Catherine; Sukumar, Prathima

    2010-01-01

    The authors evaluated the adequacy of an extensive adaptation of the American Kaufman Assessment Battery for Children, second edition (KABC-II), for 6- to 10-year-old Kannada-speaking children of low socioeconomic status in Bangalore, South India. The adapted KABC-II was administered to 598 children. Subtests showed high reliabilities, the…

  10. A field operational test on valve-regulated lead-acid absorbent-glass-mat batteries in micro-hybrid electric vehicles. Part I. Results based on kernel density estimation

    NASA Astrophysics Data System (ADS)

    Schaeck, S.; Karspeck, T.; Ott, C.; Weckler, M.; Stoermer, A. O.

    2011-03-01

    In March 2007 the BMW Group has launched the micro-hybrid functions brake energy regeneration (BER) and automatic start and stop function (ASSF). Valve-regulated lead-acid (VRLA) batteries in absorbent glass mat (AGM) technology are applied in vehicles with micro-hybrid power system (MHPS). In both part I and part II of this publication vehicles with MHPS and AGM batteries are subject to a field operational test (FOT). Test vehicles with conventional power system (CPS) and flooded batteries were used as a reference. In the FOT sample batteries were mounted several times and electrically tested in the laboratory intermediately. Vehicle- and battery-related diagnosis data were read out for each test run and were matched with laboratory data in a data base. The FOT data were analyzed by the use of two-dimensional, nonparametric kernel estimation for clear data presentation. The data show that capacity loss in the MHPS is comparable to the CPS. However, the influence of mileage performance, which cannot be separated, suggests that battery stress is enhanced in the MHPS although a battery refresh function is applied. Anyway, the FOT demonstrates the unsuitability of flooded batteries for the MHPS because of high early capacity loss due to acid stratification and because of vanishing cranking performance due to increasing internal resistance. Furthermore, the lack of dynamic charge acceptance for high energy regeneration efficiency is illustrated. Under the presented FOT conditions charge acceptance of lead-acid (LA) batteries decreases to less than one third for about half of the sample batteries compared to new battery condition. In part II of this publication FOT data are presented by multiple regression analysis (Schaeck et al., submitted for publication [1]).

  11. Stress-strain dependence for soy-protein nanofiber mats

    NASA Astrophysics Data System (ADS)

    Khansari, S.; Sinha-Ray, S.; Yarin, A. L.; Pourdeyhimi, B.

    2012-02-01

    Soy protein/nylon 6 monolithic and core-shell nanofibers were solution-blown and collected on a rotating drum as fiber mats. Tensile tests of rectangular strips of these mats revealed their stress-strain dependences. These dependences were linear at low strains which correspond to their elastic behavior. Then, a plastic-like nonlinearity sets in, which is followed by catastrophic rupture. Parameters such as Young's modulus, yield stress, and specific strain energy were measured. The results were rationalized in the framework of the phenomenological elastic-plastic model, as well as a novel micromechanical model (the latter attributes plasticity to bond rapture between the individual overstressed fibers in the mat). Besides, the effects of stretching history, rate of stretching, and winding velocity of the collector drum on the strength-related parameters are studied. The results for soy protein/nylon 6 nanofiber mats are also compared to those for solution blown pure nylon 6 mats, which were produced and tested in the same way.

  12. Sample Size Reassessment and Hypothesis Testing in Adaptive Survival Trials

    PubMed Central

    Magirr, Dominic; Jaki, Thomas; Koenig, Franz; Posch, Martin

    2016-01-01

    Mid-study design modifications are becoming increasingly accepted in confirmatory clinical trials, so long as appropriate methods are applied such that error rates are controlled. It is therefore unfortunate that the important case of time-to-event endpoints is not easily handled by the standard theory. We analyze current methods that allow design modifications to be based on the full interim data, i.e., not only the observed event times but also secondary endpoint and safety data from patients who are yet to have an event. We show that the final test statistic may ignore a substantial subset of the observed event times. An alternative test incorporating all event times is found, where a conservative assumption must be made in order to guarantee type I error control. We examine the power of this approach using the example of a clinical trial comparing two cancer therapies. PMID:26863139

  13. Flight Test of an L(sub 1) Adaptive Controller on the NASA AirSTAR Flight Test Vehicle

    NASA Technical Reports Server (NTRS)

    Gregory, Irene M.; Xargay, Enric; Cao, Chengyu; Hovakimyan, Naira

    2010-01-01

    This paper presents results of a flight test of the L-1 adaptive control architecture designed to directly compensate for significant uncertain cross-coupling in nonlinear systems. The flight test was conducted on the subscale turbine powered Generic Transport Model that is an integral part of the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. The results presented are for piloted tasks performed during the flight test.

  14. Microcomputer Network for Computerized Adaptive Testing (CAT): Program Listing. Supplement.

    DTIC Science & Technology

    1984-03-01

    ITEIINFOi].LATENCY aG 1); END; END; END; END; END; (a ctout a) BEGIN (a outputreeulte ) % 4PIl’FOHEADER; I t- 8: SIITIMlE t- 8.8; L I NESOUT: -8; %.q.NO 48...CeIncrement value -- Theta in each row in table is OT larger than previous row * etest directory name*3’ INDEXNAME - ’CATDATA:TESTINDEX.DATA’ C test...Jun 24 11:31 1383 GIGR.DIR/G.SUBRT. TEXT (Main menu graphics procedures) Page 1 (aFile last modified : Mau S. 1983 NPRIJC aG . SU6RTa): (athis

  15. ProMAT: protein microarray analysis tool

    SciTech Connect

    White, Amanda M.; Daly, Don S.; Varnum, Susan M.; Anderson, Kevin K.; Bollinger, Nikki; Zangar, Richard C.

    2006-04-04

    Summary: ProMAT is a software tool for statistically analyzing data from ELISA microarray experiments. The software estimates standard curves, sample protein concentrations and their uncertainties for multiple assays. ProMAT generates a set of comprehensive figures for assessing results and diagnosing process quality. The tool is available for Windows or Mac, and is distributed as open-source Java and R code. Availability: ProMAT is available at http://www.pnl.gov/statistics/ProMAT. ProMAT requires Java version 1.5.0 and R version 1.9.1 (or more recent versions) which are distributed with the tool.

  16. Adapting tests of sign language assessment for other sign languages--a review of linguistic, cultural, and psychometric problems.

    PubMed

    Haug, Tobias; Mann, Wolfgang

    2008-01-01

    Given the current lack of appropriate assessment tools for measuring deaf children's sign language skills, many test developers have used existing tests of other sign languages as templates to measure the sign language used by deaf people in their country. This article discusses factors that may influence the adaptation of assessment tests from one natural sign language to another. Two tests which have been adapted for several other sign languages are focused upon: the Test for American Sign Language and the British Sign Language Receptive Skills Test. A brief description is given of each test as well as insights from ongoing adaptations of these tests for other sign languages. The problems reported in these adaptations were found to be grounded in linguistic and cultural differences, which need to be considered for future test adaptations. Other reported shortcomings of test adaptation are related to the question of how well psychometric measures transfer from one instrument to another.

  17. Hypersaline Microbial Mat Lipid Biomarkers

    NASA Technical Reports Server (NTRS)

    Jahnke, Linda L.; Embaye, Tsegereda; Turk, Kendra A.; Summons, Roger E.

    2002-01-01

    Lipid biomarkers and compound specific isotopic abundances are powerful tools for studies of contemporary microbial ecosystems. Knowledge of the relationship of biomarkers to microbial physiology and community structure creates important links for understanding the nature of early organisms and paleoenvironments. Our recent work has focused on the hypersaline microbial mats in evaporation ponds at Guerrero Negro, Baja California Sur, Mexico. Specific biomarkers for diatoms, cyanobacteria, archaea, green nonsulfur (GNS), sulfate reducing, sulfur oxidizing and methanotrophic bacteria have been identified. Analyses of the ester-bound fatty acids indicate a highly diverse microbial community, dominated by photosynthetic organisms at the surface. The delta C-13 of cyanobacterial biomarkers such as the monomethylalkanes and hopanoids are consistent with the delta C-13 measured for bulk mat (-10%o), while a GNS biomarker, wax esters (WXE), suggests a more depleted delta C-13 for GNS biomass (-16%o). This isotopic relationship is different than that observed in mats at Octopus Spring, Yellowstone National Park (YSNP) where GNS appear to grow photoheterotrophic ally. WXE abundance, while relatively low, is most pronounced in an anaerobic zone just below the cyanobacterial layer. The WXE isotope composition at GN suggests that these bacteria utilize photoautotrophy incorporating dissolved inorganic carbon (DIC) via the 3-hydroxypropionate pathway using H2S or H2.

  18. Foam-mat Drying Technology: A Review.

    PubMed

    Hardy, Z; Jideani, V A

    2015-07-13

    This article reviews various aspects of foam-mat drying such as foam-mat drying processing technique, main additives used for foam-mat drying, foam-mat drying of liquid and solid foods, quality characteristics of foam-mat dried foods and economic and technical benefits for employing foam-mat drying. Foam-mat drying process is an alternative method which allows the removal of water from liquid materials and pureed materials. In this drying process, a liquid material is converted into foam that is stable by being whipped after adding an edible foaming agent. The stable foam is then spread out in sheet or mat and dried by using hot air (40 -90°C) at atmospheric pressure. Methyl cellulose (0.25 - 2%), egg white (3 - 20%), maltodextrin (0.5 - 05%) and gum Arabic (2 - 9%) are the commonly utilised additives for the foam-mat drying process at the given range, either combined together for their effectiveness or individual effect. The foam-mat drying process is suitable for heat sensitive, viscous and sticky products which cannot be dried using other forms of drying methods such as spray drying because of the state of product. More interest has developed for foam-mat drying because of the simplicity, cost effectiveness, high speed drying and improved product quality it provides.

  19. Adaptive Stress Testing of Airborne Collision Avoidance Systems

    NASA Technical Reports Server (NTRS)

    Lee, Ritchie; Kochenderfer, Mykel J.; Mengshoel, Ole J.; Brat, Guillaume P.; Owen, Michael P.

    2015-01-01

    This paper presents a scalable method to efficiently search for the most likely state trajectory leading to an event given only a simulator of a system. Our approach uses a reinforcement learning formulation and solves it using Monte Carlo Tree Search (MCTS). The approach places very few requirements on the underlying system, requiring only that the simulator provide some basic controls, the ability to evaluate certain conditions, and a mechanism to control the stochasticity in the system. Access to the system state is not required, allowing the method to support systems with hidden state. The method is applied to stress test a prototype aircraft collision avoidance system to identify trajectories that are likely to lead to near mid-air collisions. We present results for both single and multi-threat encounters and discuss their relevance. Compared with direct Monte Carlo search, this MCTS method performs significantly better both in finding events and in maximizing their likelihood.

  20. Adaptive interpretation of gas well deliverability tests with generating data of the IPR curve

    NASA Astrophysics Data System (ADS)

    Sergeev, V. L.; Phuong, Nguyen T. H.; Krainov, A. I.

    2017-01-01

    The paper considers topical issues of improving accuracy of estimated parameters given by data obtained from gas well deliverability tests, decreasing test time, and reducing gas emissions into the atmosphere. The aim of the research is to develop the method of adaptive interpretation of gas well deliverability tests with a resulting IPR curve and using a technique of generating data, which allows taking into account additional a priori information, improving accuracy of determining formation pressure and flow coefficients, reducing test time. The present research is based on the previous theoretical and practical findings in the spheres of gas well deliverability tests, systems analysis, system identification, function optimization and linear algebra. To test the method, the authors used the field data of deliverability tests of two wells, run in the Urengoy gas and condensate field, Tyumen Oblast. The authors suggest the method of adaptive interpretation of gas well deliverability tests with the resulting IPR curve and the possibility of generating data of bottomhole pressure and a flow rate at different test stages. The suggested method allows defining the estimates of the formation pressure and flow coefficients, optimal in terms of preassigned measures of quality, and setting the adequate number of test stages in the course of well testing. The case study of IPR curve data processing has indicated that adaptive interpretation provides more accurate estimates on the formation pressure and flow coefficients, as well as reduces the number of test stages.

  1. The Application of the Monte Carlo Approach to Cognitive Diagnostic Computerized Adaptive Testing With Content Constraints

    ERIC Educational Resources Information Center

    Mao, Xiuzhen; Xin, Tao

    2013-01-01

    The Monte Carlo approach which has previously been implemented in traditional computerized adaptive testing (CAT) is applied here to cognitive diagnostic CAT to test the ability of this approach to address multiple content constraints. The performance of the Monte Carlo approach is compared with the performance of the modified maximum global…

  2. Practical Issues in Large-Scale High-Stakes Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Mills, Craig N.; Stocking, Martha L.

    Computerized adaptive testing (CAT), while well-grounded in psychometric theory, has had few large-scale applications for high-stakes, secure tests in the past. This is now changing as the cost of computing has declined rapidly. As is always true where theory is translated into practice, many practical issues arise. This paper discusses a number…

  3. An Enhanced Approach to Combine Item Response Theory with Cognitive Diagnosis in Adaptive Testing

    ERIC Educational Resources Information Center

    Wang, Chun; Zheng, Chanjin; Chang, Hua-Hua

    2014-01-01

    Computerized adaptive testing offers the possibility of gaining information on both the overall ability and cognitive profile in a single assessment administration. Some algorithms aiming for these dual purposes have been proposed, including the shadow test approach, the dual information method (DIM), and the constraint weighted method. The…

  4. Proceedings of the 1979 Computerized Adaptive Testing Conference (Wayzata, Minnesota, June 27-30, 1979).

    ERIC Educational Resources Information Center

    Weiss, David J., Ed.

    This report is the Proceedings of the third conference of its type. Included are 23 of the 25 papers presented at the conference, discussion of these papers by invited discussants, and symposium papers by a group of leaders in adaptive testing and latent trait test theory research and applications. The papers are organized into the following…

  5. Computerized Adaptive Testing for Effective and Efficient Measurement in Counseling and Education

    ERIC Educational Resources Information Center

    Weiss, David J.

    2004-01-01

    Computerized adaptive testing (CAT) is described and compared with conventional tests, and its advantages summarized. Some item response theory concepts used in CAT are summarized and illustrated. The author describes the potential usefulness of CAT in counseling and education and reviews some current issues in the implementation of CAT.

  6. Predictive Validity of Conventional and Adaptive Tests in an Air Force Training Environment. Interim Report.

    ERIC Educational Resources Information Center

    Sympson, James B.; And Others

    Conventional Armed Services Vocational Aptitude Battery-7 (ASVAB) Arithmetic Reasoning and Word Knowledge tests, were compared with computer-administered adaptive tests as predictors of performance in an Air Force Jet Engine Mechanic training course (n=495). Results supported earlier research in showing somewhat longer examinee response times for…

  7. A Practical Computer Adaptive Testing Model for Small-Scale Scenarios

    ERIC Educational Resources Information Center

    Tao, Yu-Hui; Wu, Yu-Lung; Chang, Hsin-Yi

    2008-01-01

    Computer adaptive testing (CAT) is theoretically sound and efficient, and is commonly seen in larger testing programs. It is, however, rarely seen in a smaller-scale scenario, such as in classrooms or business daily routines, because of the complexity of most adopted Item Response Theory (IRT) models. While the Sequential Probability Ratio Test…

  8. Direct and Inverse Problems of Item Pool Design for Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Belov, Dmitry I.; Armstrong, Ronald D.

    2009-01-01

    The recent literature on computerized adaptive testing (CAT) has developed methods for creating CAT item pools from a large master pool. Each CAT pool is designed as a set of nonoverlapping forms reflecting the skill levels of an assumed population of test takers. This article presents a Monte Carlo method to obtain these CAT pools and discusses…

  9. Considering the Use of General and Modified Assessment Items in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Wyse, Adam E.; Albano, Anthony D.

    2015-01-01

    This article used several data sets from a large-scale state testing program to examine the feasibility of combining general and modified assessment items in computerized adaptive testing (CAT) for different groups of students. Results suggested that several of the assumptions made when employing this type of mixed-item CAT may not be met for…

  10. Application of Computerized Adaptive Testing to Entrance Examination for Graduate Studies in Turkey

    ERIC Educational Resources Information Center

    Bulut, Okan; Kan, Adnan

    2012-01-01

    Problem Statement: Computerized adaptive testing (CAT) is a sophisticated and efficient way of delivering examinations. In CAT, items for each examinee are selected from an item bank based on the examinee's responses to the items. In this way, the difficulty level of the test is adjusted based on the examinee's ability level. Instead of…

  11. Flight Test of Composite Model Reference Adaptive Control (CMRAC) Augmentation Using NASA AirSTAR Infrastructure

    NASA Technical Reports Server (NTRS)

    Gregory, Irene M.; Gadient, ROss; Lavretsky, Eugene

    2011-01-01

    This paper presents flight test results of a robust linear baseline controller with and without composite adaptive control augmentation. The flight testing was conducted using the NASA Generic Transport Model as part of the Airborne Subscale Transport Aircraft Research system at NASA Langley Research Center.

  12. Electrospun chitosan/polyvinyl alcohol nanofibre mats for wound healing.

    PubMed

    Charernsriwilaiwat, Natthan; Rojanarata, Theerasak; Ngawhirunpat, Tanasait; Opanasopit, Praneet

    2014-04-01

    Chitosan (CS) aqueous salt blended with polyvinyl alcohol (PVA) nanofibre mats was prepared by electrospinning. CS was dissolved with hydroxybenzotriazole (HOBt), thiamine pyrophosphate (TPP) and ethylenediaminetetraacetic acid (EDTA) in distilled water without the use of toxic or hazardous solvents. The CS aqueous salts were blended with PVA at different weight ratios, and the effect of the solution ratios was investigated. The morphologies and mechanical and swelling properties of the generated fibres were analysed. Indirect cytotoxicity studies indicated that the CS/PVA nanofibre mats were non-toxic to normal human fibroblast cells. The CS-HOBt/PVA and CS-EDTA/PVA nanofibre mats demonstrated satisfactory antibacterial activity against both gram-positive and gram-negative bacteria, and an in vivo wound healing test showed that the CS-EDTA/PVA nanofibre mats performed better than gauze in decreasing acute wound size during the first week after tissue damage. In conclusion, the biodegradable, biocompatible and antibacterial CS-EDTA/PVA nanofibre mats have potential for use as wound dressing materials.

  13. Adapt

    NASA Astrophysics Data System (ADS)

    Bargatze, L. F.

    2015-12-01

    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  14. Testing the role of luminance edges in White's illusion with contour adaptation.

    PubMed

    Betz, Torsten; Shapley, Robert; Wichmann, Felix A; Maertens, Marianne

    2015-08-01

    White's illusion is the perceptual effect that two equiluminant gray patches superimposed on a black-and-white square-wave grating appear different in lightness: A test patch placed on a dark stripe of the grating looks lighter than one placed on a light stripe. Although the effect does not depend on the aspect ratio of the test patches, and thus on the amount of border that is shared with either the dark or the light stripe, the context of each patch must, in a yet to be specified way, influence their lightness. We employed a contour adaptation paradigm (Anstis, 2013) to test the contribution of each of the test patches' edges to the perceived lightness of the test patches. We found that adapting to the edges that are oriented parallel to the grating slightly increased the lightness illusion, whereas adapting to the orthogonal edges abolished, or for some observers even reversed, the lightness illusion. We implemented a temporal adaptation mechanism in three spatial filtering models of lightness perception, and show that the models cannot account for the observed adaptation effects. We conclude that White's illusion is largely determined by edge contrast across the edge orthogonal to the grating, whereas the parallel edge has little or no influence. We suggest mechanisms that could explain this asymmetry.

  15. Evaluation of Parameters Affecting Horizontal Stability of Landing Mats

    DTIC Science & Technology

    1976-09-01

    1974. A rmathematical 11aodel tio silluatet the buckling response oif thte tria’i to th;: hora /ttntal ltAds way, atso elp. 1 h reuls o th...NO. 19R-20-0 MAT XU19, 4-FT X 4*PT ZERO ECCENTRICITY WIT420T EJGH48F NOTE NUMBERS SL LINES .RE HORIZONTAL FORC~E (LEFT) AND HORIZONTAL MOVEMENT ,RIGH...connector bars 14- TEST NO. 19-20-0 MAT XM19, 4-FT X 4-FT WIDTH 20-FT, LENGTH 48-FT ZERO ECCENTRICITY S-NG NUMBERS BYLINES ARE HORIZONTAL FORCE (LEFT) AND

  16. Exploring adaptations to the modified shuttle walking test

    PubMed Central

    Woolf-May, Kate; Meadows, Steve

    2013-01-01

    Objective The 10 m modified shuttle walking test (MSWT) is recommended to determine the functional capacity in older individuals and for patients entering cardiac rehabilitation. Participants are required to negotiate around cones set 1 m from the end markers. However, consistent comments indicate that for some individuals manoeuvring around the cones can be quite difficult. Therefore, the objective of this study was to explore differences within and between non-cardiac and postmyocardial infarction (MI) males during MSWT with and without the cones. Design Comparative study. Participants 20 post-MI (64.8±6.6, range 51–74 years) and 20 non-cardiac male controls (64.1±5.7, range 52–74 years) participated. Methods Participants performed MSWT with and without cones. Throughout, the participants expired air, and the heart rate (bpm) (HR) and ratings of perceived exertion (RPE) were measured. Participant protocol preference was recorded verbatim. Results One-way analysis of variance found no significant difference in VO2 peak (cones 20.4±5.1 vs no-cones 21.9±4.8 ml/kg/min, p=0.197) or distance ambulated (cones 631.8±132.9 m vs no-cones 662.4±164.1 m, p=0.371) between protocols or groups. Analysis comparing lines of regression showed a significant trajectory difference in VO2 (ml/kg/min) (p<0.01) between protocols with higher HR (p<0.01) and respiratory exchange ratio (RER, p<0.001) values during cones. RPEs were higher for post-MIs versus controls during both protocols (p<0.05). Post-MIs taking β-blockers produce significantly lower HR values. The χ2 analysis found no significant difference in protocol preference (no-cones: all n=25, 63%; post-MIs n=13, 65%; and controls n=12, 60%). Conclusions Post-MIs found both protocols subjectively harder than controls with no significant difference in the VO2 peak. However, both groups worked at a lesser percentage of their anaerobic threshold during no-cones protocol as indicated by lower RER values

  17. New crosslinkers for electrospun chitosan fibre mats. Part II: mechanical properties

    PubMed Central

    Donius, Amalie E.; Kiechel, Marjorie A.; Schauer, Caroline L.; Wegst, Ulrike G. K.

    2013-01-01

    Few studies exist on the mechanical performance of crosslinked electrospun chitosan (CS) fibre mats. In this study, we show that the mat structure and mechanical performance depend on the different crosslinking agents genipin, epichlorohydrin (ECH), and hexamethylene-1,6-diaminocarboxysulphonate (HDACS), as well as the post-electrospinning heat and base activation treatments. The mat structure was imaged by field emission scanning electron microscopy and the mechanical performance was tested in tension. The elastic modulus, tensile strength, strain at failure and work to failure were found to range from 52 to 592 MPa, 2 to 30 MPa, 2 to 31 per cent and 0.041 to 3.26 MJ m−3, respectively. In general, neat CS mats were found to be the stiffest and the strongest, though least ductile, while CS–ECH mats were the least stiff, weakest, but the most ductile, and CS–HDACS fibre mats exhibited intermediary mechanical properties. The mechanical performance of the mats is shown to reflect differences in the fibre diameter, number of fibre–fibre contacts formed within the mat, as well as varying intermolecular bonding and moisture content. The findings reported here complement the chemical properties of the mats, described in part I of this study. PMID:23349435

  18. New crosslinkers for electrospun chitosan fibre mats. Part II: mechanical properties.

    PubMed

    Donius, Amalie E; Kiechel, Marjorie A; Schauer, Caroline L; Wegst, Ulrike G K

    2013-04-06

    Few studies exist on the mechanical performance of crosslinked electrospun chitosan (CS) fibre mats. In this study, we show that the mat structure and mechanical performance depend on the different crosslinking agents genipin, epichlorohydrin (ECH), and hexamethylene-1,6-diaminocarboxysulphonate (HDACS), as well as the post-electrospinning heat and base activation treatments. The mat structure was imaged by field emission scanning electron microscopy and the mechanical performance was tested in tension. The elastic modulus, tensile strength, strain at failure and work to failure were found to range from 52 to 592 MPa, 2 to 30 MPa, 2 to 31 per cent and 0.041 to 3.26 MJ m(-3), respectively. In general, neat CS mats were found to be the stiffest and the strongest, though least ductile, while CS-ECH mats were the least stiff, weakest, but the most ductile, and CS-HDACS fibre mats exhibited intermediary mechanical properties. The mechanical performance of the mats is shown to reflect differences in the fibre diameter, number of fibre-fibre contacts formed within the mat, as well as varying intermolecular bonding and moisture content. The findings reported here complement the chemical properties of the mats, described in part I of this study.

  19. The Extracellular Matrix in Photosynthetic Mats: A Cyanobacterial Gingerbread House

    NASA Astrophysics Data System (ADS)

    Stuart, R.; Stannard, W.; Bebout, B.; Pett-Ridge, J.; Mayali, X.; Weber, P. K.; Lipton, M. S.; Lee, J.; Everroad, R. C.; Thelen, M.

    2014-12-01

    Hypersaline laminated cyanobacterial mats are excellent model systems for investigating photoautotrophic contributions to biogeochemical cycling on a millimeter scale. These self-sustaining ecosystems are characterized by steep physiochemical gradients that fluctuate dramatically on hour timescales, providing a dynamic environment to study microbial response. However, elucidating the distribution of energy from light absorption into biomass requires a complete understanding of the various constituents of the mat. Extracellular polymeric substances (EPS), which can be composed of proteins, polysaccharides, lipids and DNA are a major component of these mats and may function in the redistribution of nutrients and metabolites within the community. To test this notion, we established a model mat-building culture for comparison with the phylogenetically diverse natural mat communities. In these two systems we determined how proteins and glycans in the matrix changed as a function of light and tracked nutrient flow from the matrix. Using mass spectrometry metaproteomics analysis, we found homologous proteins in both field and culture extracellular matrix that point to cyanobacterial turnover of amino acids, inorganic nutrients, carbohydrates and nucleic acids from the EPS. Other abundant functions identified included oxidative stress response from both the cyanobacteria and heterotrophs and cyanobacterial structural proteins that may play a role in mat cohesion. Several degradative enzymes also varied in abundance in the EPS in response to light availability, suggesting active secretion. To further test cyanobacterial EPS turnover, we generated isotopically-labeled EPS and used NanoSIMS to trace uptake of this labeled EPS. Our findings suggest Cyanobacteria may facilitate nutrient transfer to other groups, as well as uptake of their own products through degradation of EPS components. This work provides evidence for the essential roles of EPS for storage, structural

  20. Wall interference tests of a CAST 10-2/DOA 2 airfoil in an adaptive-wall test section

    NASA Technical Reports Server (NTRS)

    Mineck, Raymond E.

    1987-01-01

    A wind-tunnel investigation of a CAST 10-2/DOA 2 airfoil model has been conducted in the adaptive-wall test section of the Langley 0.3-Meter Transonic Cryogenic Tunnel (TCT) and in the National Aeronautical Establishment High Reynolds Number Two-Dimensional Test Facility. The primary goal of the tests was to assess two different wall-interference correction techniques: adaptive test-section walls and classical analytical corrections. Tests were conducted over a Mach number range from 0.3 to 0.8 and over a chord Reynolds number range from 6 million to 70 million. The airfoil aerodynamic characteristics from the tests in the 0.3-m TCT have been corrected for wall interference by the movement of the adaptive walls. No additional corrections for any residual interference have been applied to the data, to allow comparison with the classically corrected data from the same model in the conventional National Aeronautical Establishment facility. The data are presented graphically in this report as integrated force-and-moment coefficients and chordwise pressure distributions.

  1. Flicker adaptation or superimposition raises the apparent spatial frequency of coarse test gratings.

    PubMed

    Kaneko, Sae; Giaschi, Deborah; Anstis, Stuart

    2015-03-01

    Independent channels respond to both the spatial and temporal characteristics of visual stimuli. Gratings <3 cycles per degree (cpd) are sensed by transient channels that prefer intermittent stimulation, while gratings >3 cpd are sensed by sustained channels that prefer steady stimulation. From this we predict that adaptation to a spatially uniform flickering field will selectively adapt the transient channels and raise the apparent spatial frequency of coarse sinusoidal gratings. Observers adapted to a spatially uniform field whose upper or lower half was steady and whose other half was flickering. They then adjusted the spatial frequency of a stationary test (matching) grating on the previously unmodulated half field until it matched the apparent spatial frequency of a grating falling on the previously flickering half field. The adapting field flickered at 8 Hz and the spatial frequency of the gratings was varied in octave steps from 0.25 to 16 cpd. As predicted, adapting to flicker raised the apparent spatial frequency of the test gratings. The aftereffect reached a peak of 11% between 0.5 and 1 cpd and disappeared above 4 cpd. We also observed that superimposed 10 Hz luminance flicker raised the apparent spatial frequency of 0.5 cpd test gratings. The effect was not seen with slower flicker or finer test gratings. Altogether, our study suggests that apparent spatial frequency is determined by the balance between transient and sustained channels and that an imbalance between the channels caused by flicker can alter spatial frequency perception.

  2. LUNAR MODULE TEST ARTICLE [LTA] [2R] IS MOVED FOR MATING TO LUNAR MODULE ADAPTER

    NASA Technical Reports Server (NTRS)

    1967-01-01

    The Lunar Module Test Article [LTA] 2R, for the second Saturn V mission, is being moved from the low bay of the Manned Spacecraft Operations Building for mating with the spacecraft Lunar Module Adapter. The second Saturn V [502], except for a different lunar return trajectory, will be a repeat of the Apollo 4 unmanned Earth orbital flight of a high apogee for systems testing using several propulsion system burns and a heat shield test at lunar re-entry speed.

  3. Proceedings of the Computerized Adaptive Testing Conference (1979) Held at Wayzata, Minnesota on 27-30 June 1979,

    DTIC Science & Technology

    1980-09-01

    Computerized Testing in the Federal Armed Forces ........................... Wolfgang Wildgrube 68 Session 3: Adaptive Mastery Testing 78 Some Decision...FORCES WOLFGANG WILDGRUBE GERMAN MINISTRY OF DEFENSE *A paper entitled "Test Construction Using Adaptive Administration Techniques," .1 by Wolfgang ...TESTING IN THE FEDERAL ARMED FORCES WOLFGANG WILDGRUBE GERMAN MINISTRY OF DEFENSE The Federal Armed Forces (FAF) consists of about 480,000 soldiers

  4. Linguistic and cultural adaptation needs of Mexican American nursing students related to multiple-choice tests.

    PubMed

    Lujan, Josefina

    2008-07-01

    Hispanic nurses represent less than 2% of the current U.S. nursing workforce, despite that approximately 14% of the nation's population is Hispanic. There is an urgent need to correct the gross underrepresentation of Mexican Americans, the largest subgroup among Hispanics, in the U.S. nursing workforce to provide culturally concordant care. One solution is to increase the academic success of Mexican American nursing students with English as a second language through improved linguistic and cultural adaptation to multiple-choice tests. This article will discuss these students' linguistic and cultural adaptation needs related to multiple-choice tests and will also present several intervention strategies and a case study.

  5. Biofilm/Mat assays for budding yeast.

    PubMed

    Cullen, Paul J

    2015-02-02

    Many microbial species form biofilms/mats under nutrient-limiting conditions, and fungal pathogens rely on this social behavior for virulence. In budding yeast, mat formation is dependent on the mucin-like flocculin Flo11, which promotes cell-to-cell and cell-to-substrate adhesion in mats. The biofilm/mat assays described here allow the evaluation of the role of Flo11 in the formation of mats. Cells are grown on surfaces with different degrees of rigidity to assess their expansion and three-dimensional architecture, and the cells are also exposed to plastic surfaces to quantify their adherence. These assays are broadly applicable to studying biofilm/mat formation in microbial species.

  6. Bentonite mat demonstration. Final report

    SciTech Connect

    Serrato, M.G.

    1994-12-30

    The Bentonite Mat Demonstration was developed to provide the Environmental Restoration Department with field performance characteristics and engineering data for an alternative closure cover system configuration. The demonstration was initiated in response to regulatory concerns regarding the use of an alternative cover system for future design configurations. These design considerations are in lieu of the US Environmental Protection Agency (EPA) Recommended Design for Closure Cover Systems and specifically a single compacted kaolin clay layer with a hydraulic conductivity of 1 {times} 10{sup {minus}7} cm/sec. This alternative configuration is a composite geosynthetic material hydraulic barrier consisting from bottom to top: 2 ft compacted sandy clay layer (typical local Savannah River Site soil type) that is covered by a bentonite mat--geosynthetic clay liner (GCL) and is overlaid by a 40 mil High Density Polyethylene (HDPE) geomembrane--flexible membrane liner. This effort was undertaken to obtain and document the necessary field performance/engineering data for future designs and meet regulatory technical requirements for an alternative cover system configuration. The composite geosynthetic materials hydraulic barrier is the recommended alternative cover system configuration for containment of hazardous and low level radiological waste layers that have a high potential of subsidence to be used at the Savannah River Site (SRS). This alternative configuration mitigates subsidence effects in providing a flexible, lightweight cover system to maintain the integrity of the closure. The composite geosynthetic materials hydraulic barrier is recommended for the Sanitary Landfill and Low Level Radiological Waste Disposal Facility (LLRWDF) Closures.

  7. MatLab Script and Functional Programming

    NASA Technical Reports Server (NTRS)

    Shaykhian, Gholam Ali

    2007-01-01

    MatLab Script and Functional Programming: MatLab is one of the most widely used very high level programming languages for scientific and engineering computations. It is very user-friendly and needs practically no formal programming knowledge. Presented here are MatLab programming aspects and not just the MatLab commands for scientists and engineers who do not have formal programming training and also have no significant time to spare for learning programming to solve their real world problems. Specifically provided are programs for visualization. The MatLab seminar covers the functional and script programming aspect of MatLab language. Specific expectations are: a) Recognize MatLab commands, script and function. b) Create, and run a MatLab function. c) Read, recognize, and describe MatLab syntax. d) Recognize decisions, loops and matrix operators. e) Evaluate scope among multiple files, and multiple functions within a file. f) Declare, define and use scalar variables, vectors and matrices.

  8. Adaptive identification and interpretation of pressure transient tests of horizontal wells: challenges and perspectives

    NASA Astrophysics Data System (ADS)

    Sergeev, V. L.; Van Hoang, Dong

    2016-09-01

    The paper deals with a topical issue of defining oil reservoir properties during transient tests of horizontal wells equipped with information-measuring systems and reducing well downtime. The aim is to consider challenges and perspectives of developing models and algorithms for adaptive identification and interpretation of transient tests in horizontal wells with pressure buildup curve analysis. The models and algorithms should allow analyzing flow behavior, defining oil reservoir properties and determining well test completion time, as well as reducing well downtime. The present paper is based on the previous theoretical and practical findings in the spheres of transient well testing, systems analysis, system identification, function optimization and linear algebra. Field data and results of transient well tests with pressure buildup curve analysis have also been considered. The suggested models and algorithms for adaptive interpretation of transient tests conducted in horizontal wells with resulting pressure buildup curve make it possible to analyze flow behavior, as well as define the reservoir properties and determine well test completion time. The algorithms for adaptive interpretation are based on the integrated system of radial flow PBC models with time- dependent variables, account of additional a priori information and estimates of radial flow permeability. Optimization problems are solved with the case study of PBC interpretation for five horizontal wells of the Verkhnechonsk field.

  9. Effects of tacky mat contamination on bond degradation for Chemlok/liner and NBR/liner bonds

    NASA Technical Reports Server (NTRS)

    Padilla, A. M.

    1989-01-01

    Tacky mats are placed by the rubber lay-up areas for the solid rocket motor segments. These mats dust off the shoes prior to entering the platform where the lay-up work is performed. The possibility exists that a tacky mat could be touched with gloved hands prior to handling the uncured nitride butadiene rubber (NBR). Tests were run to determine if NBR were accidentally touched would there be any degradation of the liner/NBR bond. The tacky mats were judged solely on the basis of bond degradation caused by either direct or indirect contamination. Test results all indicate that there was no notable NBR/Chemlok or liner/NBR bond degradation on samples that came into contact with the tacky mat material. Testing procedures are described. The tacky mat adhesive composition does not contain fluorocarbons or release agents that would affect bonding.

  10. Applications of Computerized Adaptive Testing. Proceedings of a Symposium presented at the Annual Convention of the Military Testing Association (18th, October 1976). Research Report 77-1.

    ERIC Educational Resources Information Center

    Weiss, David J., Ed.

    This symposium consists of five papers and presents some recent developments in adaptive testing which have applications to several military testing problems. The overview, by James R. McBride, defines adaptive testing and discusses some of its item selection and scoring strategies. Item response theory, or item characteristic curve theory, is…

  11. An Investigation of Procedures for Computerized Adaptive Testing Using Partial Credit Scoring.

    ERIC Educational Resources Information Center

    Koch, William R.; Dodd, Barbara G.

    1989-01-01

    Various aspects of the computerized adaptive testing (CAT) procedure for partial credit scoring were manipulated, focusing on the effects of the manipulations on operational characteristics of the CAT. The effects of item-pool size, item-pool information, and stepsizes used along the trait continuum were assessed. (TJH)

  12. Stratified and Maximum Information Item Selection Procedures in Computer Adaptive Testing

    ERIC Educational Resources Information Center

    Deng, Hui; Ansley, Timothy; Chang, Hua-Hua

    2010-01-01

    In this study we evaluated and compared three item selection procedures: the maximum Fisher information procedure (F), the a-stratified multistage computer adaptive testing (CAT) (STR), and a refined stratification procedure that allows more items to be selected from the high a strata and fewer items from the low a strata (USTR), along with…

  13. Operational Characteristics of Adaptive Testing Procedures Using the Graded Response Model.

    ERIC Educational Resources Information Center

    Dodd, Barbara G.; And Others

    1989-01-01

    General guidelines are developed to assist practitioners in devising operational computerized adaptive testing systems based on the graded response model. The effects of the following major variables were examined: item pool size; stepsize used along the trait continuum until maximum likelihood estimation could be calculated; and stopping rule…

  14. Optimal Stratification of Item Pools in a-Stratified Computerized Adaptive Testing. Research Report.

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    A method based on 0-1 linear programming (LP) is presented to stratify an item pool optimally for use in "alpha"-stratified adaptive testing. Because the 0-1 LP model belongs to the subclass of models with a network-flow structure, efficient solutions are possible. The method is applied to a previous item pool from the computerized…

  15. Item Response Theory and Computerized Adaptive Testing Conference Proceedings (Wayzata, Minnesota, July 27-30, 1982).

    ERIC Educational Resources Information Center

    Weiss, David J., Ed.

    This report contains the Proceedings of the 1982 Item Response Theory and Computerized Adaptive Testing Conference. The papers and their discussions are organized into eight sessions: (1) "Developments in Latent Trait Theory," with papers by Fumiko Samejima and Michael V. Levine; (2) "Parameter Estimation," with papers by…

  16. Optimal Item Pool Design for a Highly Constrained Computerized Adaptive Test

    ERIC Educational Resources Information Center

    He, Wei

    2010-01-01

    Item pool quality has been regarded as one important factor to help realize enhanced measurement quality for the computerized adaptive test (CAT) (e.g., Flaugher, 2000; Jensema, 1977; McBride & Wise, 1976; Reckase, 1976; 2003; van der Linden, Ariel, & Veldkamp, 2006; Veldkamp & van der Linden, 2000; Xing & Hambleton, 2004). However, studies are…

  17. A Revised Version of the Norwegian Adaptation of the Test Anxiety Inventory in a Heterogeneous Population

    ERIC Educational Resources Information Center

    Oktedalen, Tuva; Hagtvet, Knut A.

    2011-01-01

    Confirmatory factor analysis and Multiple Indicators, Multiple Causes (MIMIC) modeling were employed to investigate psychometric properties of a revised adaptation of the Norwegian version of the Test Anxiety Inventory (RTAIN) in a sample of 456 students. The study supported the Norwegian version as a useful inventory for measuring the components…

  18. Adapting the Bilingual Aphasia Test to Rarotongan (Cook Islands Maori): Linguistic and Clinical Considerations

    ERIC Educational Resources Information Center

    Amberber, Amanda Miller

    2011-01-01

    This article describes the adaptation of the Bilingual Aphasia Test (BAT) to the Rarotongan dialect of Cook Islands Maori, a Polynesian language spoken in the Cook Islands and expatriate communities. A brief linguistic sketch of Rarotongan is presented. As Rarotongan is characterised by a complex pronominal system, "a" versus "o" possession and…

  19. The Adaptation of Naval Enlistees Scoring in Mental Group 4 on the Armed Forces Qualification Test.

    ERIC Educational Resources Information Center

    Plag, John A.; And Others

    This report presents findings from a study evaluating differences in the adaptation of "average" and mentally marginal sailors during four years of military service. Sailors with Armed Forces Qualification Test (AFQT) scores of 50 are significantly superior to Category 4 enlistees on military performance measures which stress cognitive…

  20. A Monte Carlo Approach to the Design, Assembly, and Evaluation of Multistage Adaptive Tests

    ERIC Educational Resources Information Center

    Belov, Dmitry I.; Armstrong, Ronald D.

    2008-01-01

    This article presents an application of Monte Carlo methods for developing and assembling multistage adaptive tests (MSTs). A major advantage of the Monte Carlo assembly over other approaches (e.g., integer programming or enumerative heuristics) is that it provides a uniform sampling from all MSTs (or MST paths) available from a given item pool.…

  1. The Use of Unidimensional Item Parameter Estimates of Multidimensional Items in Adaptive Testing.

    ERIC Educational Resources Information Center

    Ackerman, Terry A.

    The purpose of this study was to investigate the effect of using multidimensional items in a computer adaptive test (CAT) setting which assumes a unidimensional item response theory (IRT) framework. Previous research has suggested that the composite of multidimensional abilities being estimated by a unidimensional IRT model is not constant…

  2. On the Impact of Adaptive Test Question Selection for Learning Efficiency

    ERIC Educational Resources Information Center

    Barla, Michal; Bielikova, Maria; Ezzeddinne, Anna Bou; Kramar, Tomas; Simko, Marian; Vozar, Oto

    2010-01-01

    In this paper we present a method for adaptive selection of test questions according to the individual needs of students within a web-based educational system. It functions as a combination of three particular methods. The first method is based on the course structure and focuses on the selection of the most appropriate topic for learning. The…

  3. Test Adaptation and Cross-Cultural Assessment From a Business Perspective: Issues and Recommendations

    ERIC Educational Resources Information Center

    Casillas, Alex; Robbins, Steven B.

    2005-01-01

    Test adaptation and cross-cultural assessment activities are skyrocketing as the demand for educational opportunities and personnel selection grow both within the United States and across the industrializing world. We chose a qualitative, case study approach to identify central themes encountered by ACT, a not-for-profit organization that has…

  4. Bayesian Item Selection Criteria for Adaptive Testing. Research Report 96-01.

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    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 complexity involved in a fully Bayesian approach, but…

  5. Incorporation of Content Balancing Requirements in Stratification Designs for Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Leung, Chi-Keung; Chang, Hua-Hua; Hau, Kit-Tai

    2003-01-01

    Studied three stratification designs for computerized adaptive testing in conjunction with three well-developed content balancing methods. Simulation study results show substantial differences in item overlap rate and pool utilization among different methods. Recommends an optimal combination of stratification design and content balancing method.…

  6. Taylor Approximations to Logistic IRT Models and Their Use in Adaptive Testing.

    ERIC Educational Resources Information Center

    Veerkamp, Wim J. J.

    2000-01-01

    Showed how Taylor approximation can be used to generate a linear approximation to a logistic item characteristic curve and a linear ability estimator. Demonstrated how, for a specific simulation, this could result in the special case of a Robbins-Monro item selection procedure for adaptive testing. (SLD)

  7. Restrictive Stochastic Item Selection Methods in Cognitive Diagnostic Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Wang, Chun; Chang, Hua-Hua; Huebner, Alan

    2011-01-01

    This paper proposes two new item selection methods for cognitive diagnostic computerized adaptive testing: the restrictive progressive method and the restrictive threshold method. They are built upon the posterior weighted Kullback-Leibler (KL) information index but include additional stochastic components either in the item selection index or in…

  8. Psychometric Evaluation of the Italian Adaptation of the Test of Inferential and Creative Thinking

    ERIC Educational Resources Information Center

    Faraci, Palmira; Hell, Benedikt; Schuler, Heinz

    2016-01-01

    This article describes the psychometric properties of the Italian adaptation of the "Analyse des Schlussfolgernden und Kreativen Denkens" (ASK; Test of Inferential and Creative Thinking) for measuring inferential and creative thinking. The study aimed to (a) supply evidence for the factorial structure of the instrument, (b) describe its…

  9. An Adaptive Testing Strategy for Mastery Decisions. Research Report 79-5.

    ERIC Educational Resources Information Center

    Kingsbury, G. Gage; Weiss, David J.

    The theory and technology of item characteristic curve (ICC) response theory and adaptive testing were applied to judging individuals' competencies against a prespecified mastery level to determine whether each individual is a "master" or "nonmaster" of a specified content domain. Items from two conventionally administered mastery tests…

  10. The Development and Evaluation of a Software Prototype for Computer-Adaptive Testing

    ERIC Educational Resources Information Center

    Lilley, M.; Barker, T.; Britton, C.

    2004-01-01

    This paper presents ongoing research at the University of Hertfordshire on the use of computer-adaptive tests (CATs) in Higher Education. A software prototype based on Item Response Theory has been developed and is described here. This application was designed to estimate the level of proficiency in English for those students whose first language…

  11. A hierarchical Bayesian approach to adaptive vision testing: A case study with the contrast sensitivity function

    PubMed Central

    Gu, Hairong; Kim, Woojae; Hou, Fang; Lesmes, Luis Andres; Pitt, Mark A.; Lu, Zhong-Lin; Myung, Jay I.

    2016-01-01

    Measurement efficiency is of concern when a large number of observations are required to obtain reliable estimates for parametric models of vision. The standard entropy-based Bayesian adaptive testing procedures addressed the issue by selecting the most informative stimulus in sequential experimental trials. Noninformative, diffuse priors were commonly used in those tests. Hierarchical adaptive design optimization (HADO; Kim, Pitt, Lu, Steyvers, & Myung, 2014) further improves the efficiency of the standard Bayesian adaptive testing procedures by constructing an informative prior using data from observers who have already participated in the experiment. The present study represents an empirical validation of HADO in estimating the human contrast sensitivity function. The results show that HADO significantly improves the accuracy and precision of parameter estimates, and therefore requires many fewer observations to obtain reliable inference about contrast sensitivity, compared to the method of quick contrast sensitivity function (Lesmes, Lu, Baek, & Albright, 2010), which uses the standard Bayesian procedure. The improvement with HADO was maintained even when the prior was constructed from heterogeneous populations or a relatively small number of observers. These results of this case study support the conclusion that HADO can be used in Bayesian adaptive testing by replacing noninformative, diffuse priors with statistically justified informative priors without introducing unwanted bias. PMID:27105061

  12. A Simulation Study of Methods for Assessing Differential Item Functioning in Computerized Adaptive Tests.

    ERIC Educational Resources Information Center

    Zwick, Rebecca; And Others

    1994-01-01

    Simulated data were used to investigate the performance of modified versions of the Mantel-Haenszel method of differential item functioning (DIF) analysis in computerized adaptive tests (CAT). Results indicate that CAT-based DIF procedures perform well and support the use of item response theory-based matching variables in DIF analysis. (SLD)

  13. A Simulation Study of Methods for Assessing Differential Item Functioning in Computer-Adaptive Tests.

    ERIC Educational Resources Information Center

    Zwick, Rebecca; And Others

    Simulated data were used to investigate the performance of modified versions of the Mantel-Haenszel and standardization methods of differential item functioning (DIF) analysis in computer-adaptive tests (CATs). Each "examinee" received 25 items out of a 75-item pool. A three-parameter logistic item response model was assumed, and…

  14. Effect of Rasch Calibration on Ability and DIF Estimation in Computer-Adaptive Tests.

    ERIC Educational Resources Information Center

    Zwick, Rebecca; And Others

    1995-01-01

    In a simulation study of ability and estimation of differential item functioning (DIF) in computerized adaptive tests, Rasch-based DIF statistics were highly correlated with generating DIF, but DIF statistics tended to be slightly smaller than in the three-parameter logistic model analyses. (SLD)

  15. The Problem of Bias in Person Parameter Estimation in Adaptive Testing

    ERIC Educational Resources Information Center

    Doebler, Anna

    2012-01-01

    It is shown that deviations of estimated from true values of item difficulty parameters, caused for example by item calibration errors, the neglect of randomness of item difficulty parameters, testlet effects, or rule-based item generation, can lead to systematic bias in point estimation of person parameters in the context of adaptive testing.…

  16. Effects of Calibration Sample Size and Item Bank Size on Ability Estimation in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Sahin, Alper; Weiss, David J.

    2015-01-01

    This study aimed to investigate the effects of calibration sample size and item bank size on examinee ability estimation in computerized adaptive testing (CAT). For this purpose, a 500-item bank pre-calibrated using the three-parameter logistic model with 10,000 examinees was simulated. Calibration samples of varying sizes (150, 250, 350, 500,…

  17. Best Design for Multidimensional Computerized Adaptive Testing with the Bifactor Model

    ERIC Educational Resources Information Center

    Seo, Dong Gi; Weiss, David J.

    2015-01-01

    Most computerized adaptive tests (CATs) have been studied using the framework of unidimensional item response theory. However, many psychological variables are multidimensional and might benefit from using a multidimensional approach to CATs. This study investigated the accuracy, fidelity, and efficiency of a fully multidimensional CAT algorithm…

  18. Firestar-"D": Computerized Adaptive Testing Simulation Program for Dichotomous Item Response Theory Models

    ERIC Educational Resources Information Center

    Choi, Seung W.; Podrabsky, Tracy; McKinney, Natalie

    2012-01-01

    Computerized adaptive testing (CAT) enables efficient and flexible measurement of latent constructs. The majority of educational and cognitive measurement constructs are based on dichotomous item response theory (IRT) models. An integral part of developing various components of a CAT system is conducting simulations using both known and empirical…

  19. Lessons Learned in Designing and Implementing a Computer-Adaptive Test for English

    ERIC Educational Resources Information Center

    Burston, Jack; Neophytou, Maro

    2014-01-01

    This paper describes the lessons learned in designing and implementing a computer-adaptive test (CAT) for English. The early identification of students with weak L2 English proficiency is of critical importance in university settings that have compulsory English language course graduation requirements. The most efficient means of diagnosing the L2…

  20. Variable-Length Computerized Adaptive Testing Based on Cognitive Diagnosis Models

    ERIC Educational Resources Information Center

    Hsu, Chia-Ling; Wang, Wen-Chung; Chen, Shu-Ying

    2013-01-01

    Interest in developing computerized adaptive testing (CAT) under cognitive diagnosis models (CDMs) has increased recently. CAT algorithms that use a fixed-length termination rule frequently lead to different degrees of measurement precision for different examinees. Fixed precision, in which the examinees receive the same degree of measurement…

  1. SimulCAT: Windows Software for Simulating Computerized Adaptive Test Administration

    ERIC Educational Resources Information Center

    Han, Kyung T.

    2012-01-01

    Most, if not all, computerized adaptive testing (CAT) programs use simulation techniques to develop and evaluate CAT program administration and operations, but such simulation tools are rarely available to the public. Up to now, several software tools have been available to conduct CAT simulations for research purposes; however, these existing…

  2. Item Pool Design for an Operational Variable-Length Computerized Adaptive Test

    ERIC Educational Resources Information Center

    He, Wei; Reckase, Mark D.

    2014-01-01

    For computerized adaptive tests (CATs) to work well, they must have an item pool with sufficient numbers of good quality items. Many researchers have pointed out that, in developing item pools for CATs, not only is the item pool size important but also the distribution of item parameters and practical considerations such as content distribution…

  3. SIMCA T 1.0: A SAS Computer Program for Simulating Computer Adaptive Testing

    ERIC Educational Resources Information Center

    Raiche, Gilles; Blais, Jean-Guy

    2006-01-01

    Monte Carlo methodologies are frequently applied to study the sampling distribution of the estimated proficiency level in adaptive testing. These methods eliminate real situational constraints. However, these Monte Carlo methodologies are not currently supported by the available software programs, and when these programs are available, their…

  4. Organismal and spatial partitioning of energy and macronutrient transformations within a hypersaline mat.

    PubMed

    Mobberley, Jennifer M; Lindemann, Stephen R; Bernstein, Hans C; Moran, James J; Renslow, Ryan S; Babauta, Jerome; Hu, Dehong; Beyenal, Haluk; Nelson, William C

    2017-03-15

    Phototrophic mat communities are model ecosystems for studying energy cycling and elemental transformations because complete biogeochemical cycles occur over millimeter-to-centimeter scales. Characterization of energy and nutrient capture within hypersaline phototrophic mats has focused on specific processes and organisms, however little is known about community-wide distribution of and linkages between these processes. To investigate energy and macronutrient capture and flow through a structured community, the spatial and organismal distribution of metabolic functions within a compact hypersaline mat community from Hot Lake have been broadly elucidated through species-resolved metagenomics and geochemical, microbial diversity, and metabolic gradient measurements. Draft reconstructed genomes of 34 abundant organisms revealed three dominant cyanobacterial populations differentially distributed across the top layers of the mat suggesting niche separation along light and oxygen gradients. Many organisms contained diverse functional profiles, allowing for metabolic response to changing conditions within the mat. Organisms with partial nitrogen and sulfur metabolisms were widespread indicating dependence upon metabolite exchange. In addition, changes in community spatial structure were observed over the diel. These results indicate that organisms within the mat community have adapted to the temporally dynamic environmental gradients in this hypersaline mat through metabolic flexibility and fluid syntrophic interactions, including shifts in spatial arrangements.

  5. Approaching Sign Language Test Construction: Adaptation of the German Sign Language Receptive Skills Test

    ERIC Educational Resources Information Center

    Haug, Tobias

    2011-01-01

    There is a current need for reliable and valid test instruments in different countries in order to monitor deaf children's sign language acquisition. However, very few tests are commercially available that offer strong evidence for their psychometric properties. A German Sign Language (DGS) test focusing on linguistic structures that are acquired…

  6. Kansas Adapted/Special Physical Education Test Manual. Health Related Fitness and Psychomotor Testing.

    ERIC Educational Resources Information Center

    Johnson, Robert E.; Lavay, Barry

    This manual was developed to address the need for health-related physical fitness testing of children with special needs. The first section defines the components of health-related physical fitness which consist of: (1)abdominal strength and endurance measured by a sit-up test; (2) flexibility, measured by a sit and reach test; (3) upper body…

  7. Adapting the Get Yourself Tested Campaign to Reach Black and Latino Sexual-Minority Youth

    PubMed Central

    Garbers, Samantha; Friedman, Allison; Martinez, Omar; Scheinmann, Roberta; Bermudez, Dayana; Silva, Manel; Silverman, Jen; Chiasson, Mary Ann

    2016-01-01

    Background Culturally appropriate efforts are needed to increase sexually transmitted disease (STD) testing and care among Black and Latino sexual-minority youth, who are at high risk for STDs. Get Yourself Tested, a national testing campaign, has demonstrated success among youth, but it has yet to be assessed for relevance or impact among this population. Method This effort included (1) formative and materials-testing research through focus groups; (2) adaptation of existing Get Yourself Tested campaign materials to be more inclusive of Black and Latino sexual-minority youth; (3) a 3-month campaign in four venues of New York City, promoting STD testing at events and through mobile testing and online and social media platforms; (4) process evaluation of outreach activities; and (5) an outcome evaluation of testing at select campaign venues, using a preexperimental design. Results During the 3-month campaign period, the number of STD tests conducted at select campaign venues increased from a comparable 3-month baseline period. Although testing uptake through mobile vans remained low in absolute numbers, the van drew a high-prevalence sample, with positivity rates of 26.9% for chlamydia and 11.5% for gonorrhea. This article documents the process and lessons learned from adapting and implementing a local campaign for Black and Latino sexual-minority youth. PMID:27225216

  8. International Space Station Environmental Control and Life Support System Acceptance Testing for the Pressurized Mating Adapters

    NASA Technical Reports Server (NTRS)

    Williams, David E.

    2008-01-01

    The International Space Station (ISS) Pressurized Mating Adapters (PMAs) Environmental Control and Life Support (ECLS) System is comprised of three subsystems: Atmosphere Control and Supply (ACS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). PMAs 1 and 2 flew to ISS on Flight 2A and Pressurized Mating Adapter (PMA) 3 flew to ISS on Flight 3A. This paper provides a summary of the PMAs ECLS design and a detailed discussion of the ISS ECLS Acceptance Testing methodologies utilized for the PMAs.

  9. Interaction of gelatin with polyenes modulates antifungal activity and biocompatibility of electrospun fiber mats.

    PubMed

    Lakshminarayanan, Rajamani; Sridhar, Radhakrishnan; Loh, Xian Jun; Nandhakumar, Muruganantham; Barathi, Veluchamy Amutha; Kalaipriya, Madhaiyan; Kwan, Jia Lin; Liu, Shou Ping; Beuerman, Roger Wilmer; Ramakrishna, Seeram

    2014-01-01

    Topical application of antifungals does not have predictable or well-controlled release characteristics and requires reapplication to achieve therapeutic local concentration in a reasonable time period. In this article, the efficacy of five different US Food and Drug Administration-approved antifungal-loaded (amphotericin B, natamycin, terbinafine, fluconazole, and itraconazole) electrospun gelatin fiber mats were compared. Morphological studies show that incorporation of polyenes resulted in a two-fold increase in fiber diameter and the mats inhibit the growth of yeasts and filamentous fungal pathogens. Terbinafine-loaded mats were effective against three filamentous fungal species. Among the two azole antifungals compared, the itraconazole-loaded mat was potent against Aspergillus strains. However, activity loss was observed for fluconazole-loaded mats against all of the test organisms. The polyene-loaded mats displayed rapid candidacidal activities as well. Biophysical and rheological measurements indicate strong interactions between polyene antifungals and gelatin matrix. As a result, the polyenes stabilized the triple helical conformation of gelatin and the presence of gelatin decreased the hemolytic activity of polyenes. The polyene-loaded fiber mats were noncytotoxic to primary human corneal and sclera fibroblasts. The reduction of toxicity with complete retention of activity of the polyene antifungal-loaded gelatin fiber mats can provide new opportunities in the management of superficial skin infections.

  10. Interaction of gelatin with polyenes modulates antifungal activity and biocompatibility of electrospun fiber mats

    PubMed Central

    Lakshminarayanan, Rajamani; Sridhar, Radhakrishnan; Loh, Xian Jun; Nandhakumar, Muruganantham; Barathi, Veluchamy Amutha; Kalaipriya, Madhaiyan; Kwan, Jia Lin; Liu, Shou Ping; Beuerman, Roger Wilmer; Ramakrishna, Seeram

    2014-01-01

    Topical application of antifungals does not have predictable or well-controlled release characteristics and requires reapplication to achieve therapeutic local concentration in a reasonable time period. In this article, the efficacy of five different US Food and Drug Administration-approved antifungal-loaded (amphotericin B, natamycin, terbinafine, fluconazole, and itraconazole) electrospun gelatin fiber mats were compared. Morphological studies show that incorporation of polyenes resulted in a two-fold increase in fiber diameter and the mats inhibit the growth of yeasts and filamentous fungal pathogens. Terbinafine-loaded mats were effective against three filamentous fungal species. Among the two azole antifungals compared, the itraconazole-loaded mat was potent against Aspergillus strains. However, activity loss was observed for fluconazole-loaded mats against all of the test organisms. The polyene-loaded mats displayed rapid candidacidal activities as well. Biophysical and rheological measurements indicate strong interactions between polyene antifungals and gelatin matrix. As a result, the polyenes stabilized the triple helical conformation of gelatin and the presence of gelatin decreased the hemolytic activity of polyenes. The polyene-loaded fiber mats were noncytotoxic to primary human corneal and sclera fibroblasts. The reduction of toxicity with complete retention of activity of the polyene antifungal-loaded gelatin fiber mats can provide new opportunities in the management of superficial skin infections. PMID:24920895

  11. Community structure of free-floating filamentous cyanobacterial mats from the Wonder Lake geothermal springs in the Philippines.

    PubMed

    Lacap, Donnabella C; Smith, Gavin J D; Warren-Rhodes, Kimberley; Pointing, Stephen B

    2005-07-01

    Cyanobacterial mats were characterized from pools of 45-60 degrees C in near-neutral pH, low-sulphide geothermal springs in the Philippines. Mat structure did not vary with temperature. All mats possessed highly ordered layers of airspaces at both the macroscopic and microscopic level, and these appear to be an adaptation to a free-floating growth habit. Upper mat layers supported biomass with elevated carotenoid:chlorophyll a ratios and an as yet uncharacterized waxy layer on the dorsal surface. Microscopic examination revealed mats comprised a single Fischerella morphotype, with abundant heterocysts throughout mats at all temperatures. Molecular analysis of mat community structure only partly matched morphological identification. All samples supported greater 16S rDNA-defined diversity than morphology suggested, with a progressive loss in the number of genotypes with increasing temperature. Fischerella-like sequences were recovered from mats occurring at all temperatures, but some mats also yielded Oscillatoria-like sequences, although corresponding phenotypes were not observed. Phylogenetic analysis revealed that Fischerella-like sequences were most closely affiliated with Fischerella major and the Oscillatoria-like sequences with Oscillatoria amphigranulata.

  12. Nonwoven glass fiber mat reinforces polyurethane adhesive

    NASA Technical Reports Server (NTRS)

    Roseland, L. M.

    1967-01-01

    Nonwoven glass fiber mat reinforces the adhesive properties of a polyurethane adhesive that fastens hardware to exterior surfaces of aluminum tanks. The mat is embedded in the uncured adhesive. It ensures good control of the bond line and increases the peel strength.

  13. Flat laminated microbial mat communities

    NASA Astrophysics Data System (ADS)

    Franks, Jonathan; Stolz, John F.

    2009-10-01

    Flat laminated microbial mats are complex microbial ecosystems that inhabit a wide range of environments (e.g., caves, iron springs, thermal springs and pools, salt marshes, hypersaline ponds and lagoons, methane and petroleum seeps, sea mounts, deep sea vents, arctic dry valleys). Their community structure is defined by physical (e.g., light quantity and quality, temperature, density and pressure) and chemical (e.g., oxygen, oxidation/reduction potential, salinity, pH, available electron acceptors and donors, chemical species) parameters as well as species interactions. The main primary producers may be photoautotrophs (e.g., cyanobacteria, purple phototrophs, green phototrophs) or chemolithoautophs (e.g., colorless sulfur oxidizing bacteria). Anaerobic phototrophy may predominate in organic rich environments that support high rates of respiration. These communities are dynamic systems exhibiting both spatial and temporal heterogeneity. They are characterized by steep gradients with microenvironments on the submillimeter scale. Diel oscillations in the physical-chemical profile (e.g., oxygen, hydrogen sulfide, pH) and species distribution are typical for phototroph-dominated communities. Flat laminated microbial mats are often sites of robust biogeochemical cycling. In addition to well-established modes of metabolism for phototrophy (oxygenic and non-oxygenic), respiration (both aerobic and anaerobic), and fermentation, novel energetic pathways have been discovered (e.g., nitrate reduction couple to the oxidation of ammonia, sulfur, or arsenite). The application of culture-independent techniques (e.g., 16S rRNA clonal libraries, metagenomics), continue to expand our understanding of species composition and metabolic functions of these complex ecosystems.

  14. High-Resolution Adaptive Optics Test-Bed for Vision Science

    SciTech Connect

    Wilks, S C; Thomspon, C A; Olivier, S S; Bauman, B J; Barnes, T; Werner, J S

    2001-09-27

    We discuss the design and implementation of a low-cost, high-resolution adaptive optics test-bed for vision research. It is well known that high-order aberrations in the human eye reduce optical resolution and limit visual acuity. However, the effects of aberration-free eyesight on vision are only now beginning to be studied using adaptive optics to sense and correct the aberrations in the eye. We are developing a high-resolution adaptive optics system for this purpose using a Hamamatsu Parallel Aligned Nematic Liquid Crystal Spatial Light Modulator. Phase-wrapping is used to extend the effective stroke of the device, and the wavefront sensing and wavefront correction are done at different wavelengths. Issues associated with these techniques will be discussed.

  15. [Assessment of cardiorespiratory fitness in preschool children: adaptation of the 20 metres shuttle run test].

    PubMed

    Cadenas-Sánchez, Cristina; Alcántara-Moral, Francisco; Sánchez-Delgado, Guillermo; Mora-González, José; Martínez-Téllez, Borja; Herrador-Colmenero, Manuel; Jiménez-Pavón, David; Femia, Pedro; Ruiz, Jonatan R; Ortega, Francisco B

    2014-12-01

    Cardiorespiratory fitness is a strong indicator of present and future health in children and adolescents, however it is unknown whether it is for pre-schoolers, from 3 to 5 years. In the present study, we described the adaptation of the original 20m shuttle run test, it feasibility and acceptance in children from 3 to 5 years and its maximality and reliability. A total of 130 students (4.91 ± 0.89 years; 77 boys) performed the test twice, two weeks apart. The test adaptation consisted mainly in reducing the initial speed of 8.5 km/h to 6.5 km/h. The test was feasible and was well accepted in both boys and girls and the three age groups, 3, 4 and 5 years. The maximum heart rate (MHR) achieved for the entire sample was 199.4 ± 12.5 beats/min, equivalent to 97% of the estimated theoretical MHR, and no significant differences by gender or age. Mean test-retest difference (systematic error) in the number of laps achieved was 2 laps, with no significant differences between sex or age. There was no evidence of heteroscedasticity. Our results suggest the test is maximum and reliable in this age group. Future longitudinal or intervention studies using this test should take into account that changes in the test performance of 2 laps may be due to the variability of the measure, while wider changes would be attributable to the intervention or changes associated with age.

  16. Performance of ballast mats on passenger railroads: Measurement vs. projections

    NASA Astrophysics Data System (ADS)

    Hanson, C. E.; Singleton, H. L.

    2006-06-01

    Ballast mats have been installed on urban railway systems throughout the world to provide isolation of ground-borne vibrations from trains. In general, the performance has been found to be satisfactory. However, often there is a variance between the claims of the suppliers of ballast mats and the actual performance of the product in the real world. The classic case involves an infinite terminal impedance applicable to a tunnel configuration. However, a ballast mat installation outdoors on surface track with sub-grade slabs may not have the same performance as a tunnel base where sides are stiffened by walls. In order to represent this situation, Kimura developed a simplified prediction procedure based on an original Wettschureck/Kurze model, with a finite termination impedance based on a flat beam model. This prediction procedure has been tested against measurements on at-grade installations on light rail transit and commuter railway installations in Baltimore and Boston. In both cases, the model showed good agreement with measured values for the resonant frequency dip and the mid-frequency insertion loss. At higher frequencies, however, the model over-predicted the insertion loss, as do many of the models used by ballast mat suppliers. Suggestions are made to account for the discrepancies between predicted and measured values.

  17. Direct piezoelectric responses of soft composite fiber mats

    NASA Astrophysics Data System (ADS)

    Varga, M.; Morvan, J.; Diorio, N.; Buyuktanir, E.; Harden, J.; West, J. L.; Jákli, A.

    2013-04-01

    Recently soft fiber mats electrospun from solutions of Barium Titanate (BT) ferroelectric ceramics particles and polylactic acid (PLA) were found to have large (d33 ˜ 1 nm/V) converse piezoelectric signals offering a myriad of applications ranging from active implants to smart textiles. Here, we report direct piezoelectric measurements (electric signals due to mechanical stress) of the BT/PLA composite fiber mats at several BT concentrations. A homemade testing apparatus provided AC stresses in the 50 Hz-1.5 kHz-frequency range. The piezoelectric constant d33 ˜ 0.5 nC/N and the compression modulus Y ˜ 104-105 Pa found are in agreement with the prior converse piezoelectric and compressibility measurements. Importantly, the direct piezoelectric signal is large enough to power a small LCD by simple finger tapping of a 0.15 mm thick 2-cm2 area mat. We propose using these mats in active Braille cells and in liquid crystal writing tablets.

  18. Design and Preliminary Testing of the International Docking Adapter's Peripheral Docking Target

    NASA Technical Reports Server (NTRS)

    Foster, Christopher W.; Blaschak, Johnathan; Eldridge, Erin A.; Brazzel, Jack P.; Spehar, Peter T.

    2015-01-01

    The International Docking Adapter's Peripheral Docking Target (PDT) was designed to allow a docking spacecraft to judge its alignment relative to the docking system. The PDT was designed to be compatible with relative sensors using visible cameras, thermal imagers, or Light Detection and Ranging (LIDAR) technologies. The conceptual design team tested prototype designs and materials to determine the contrast requirements for the features. This paper will discuss the design of the PDT, the methodology and results of the tests, and the conclusions pertaining to PDT design that were drawn from testing.

  19. Capabilities of wind tunnels with two-adaptive walls to minimize boundary interference in 3-D model testing

    NASA Technical Reports Server (NTRS)

    Rebstock, Rainer; Lee, Edwin E., Jr.

    1989-01-01

    An initial wind tunnel test was made to validate a new wall adaptation method for 3-D models in test sections with two adaptive walls. First part of the adaptation strategy is an on-line assessment of wall interference at the model position. The wall induced blockage was very small at all test conditions. Lift interference occurred at higher angles of attack with the walls set aerodynamically straight. The adaptation of the top and bottom tunnel walls is aimed at achieving a correctable flow condition. The blockage was virtually zero throughout the wing planform after the wall adjustment. The lift curve measured with the walls adapted agreed very well with interference free data for Mach 0.7, regardless of the vertical position of the wing in the test section. The 2-D wall adaptation can significantly improve the correctability of 3-D model data. Nevertheless, residual spanwise variations of wall interference are inevitable.

  20. Full-Scale Instrumented Evaluations of Multiple Airfield Matting Systems on Soft Soil to Characterize Permanent Deformation

    DTIC Science & Technology

    2016-06-01

    experienced by the subgrade. The matting systems were tested on a California Bearing Ratio (CBR) of 6 and subjected to simulated F-15E aircraft traffic...subgrade to a California Bearing Ratio (CBR) of 6, surfacing it with airfield matting, and applying simulated F-15E aircraft traffic on the mat surface...California Bearing Ratio; Gs = specific gravity. aASTM D1557. Figure 11. Compaction curve for CH subgrade material. ERDC/GSL TR-16-15 22 Figure 12

  1. Sleep deprivation selectively disrupts top-down adaptation to cognitive conflict in the Stroop test.

    PubMed

    Gevers, Wim; Deliens, Gaetane; Hoffmann, Sophie; Notebaert, Wim; Peigneux, Philippe

    2015-12-01

    Sleep deprivation is known to exert detrimental effects on various cognitive domains, including attention, vigilance and working memory. Seemingly at odds with these findings, prior studies repeatedly failed to evidence an impact of prior sleep deprivation on cognitive interference in the Stroop test, a hallmark paradigm in the study of cognitive control abilities. The present study investigated further the effect of sleep deprivation on cognitive control using an adapted version of the Stroop test that allows to segregate top-down (attentional reconfiguration on incongruent items) and bottom-up (facilitated processing after repetitions in responses and/or features of stimuli) components of performance. Participants underwent a regular night of sleep or a night of total sleep deprivation before cognitive testing. Results disclosed that sleep deprivation selectively impairs top-down adaptation mechanisms: cognitive control no longer increased upon detection of response conflict at the preceding trial. In parallel, bottom-up abilities were found unaffected by sleep deprivation: beneficial effects of stimulus and response repetitions persisted. Changes in vigilance states due to sleep deprivation selectively impact on cognitive control in the Stroop test by affecting top-down, but not bottom-up, mechanisms that guide adaptive behaviours.

  2. Implementation of an Adaptive Controller System from Concept to Flight Test

    NASA Technical Reports Server (NTRS)

    Larson, Richard R.; Burken, John J.; Butler, Bradley S.; Yokum, Steve

    2009-01-01

    The National Aeronautics and Space Administration Dryden Flight Research Center (Edwards, California) is conducting ongoing flight research using adaptive controller algorithms. A highly modified McDonnell-Douglas NF-15B airplane called the F-15 Intelligent Flight Control System (IFCS) is used to test and develop these algorithms. Modifications to this airplane include adding canards and changing the flight control systems to interface a single-string research controller processor for neural network algorithms. Research goals include demonstration of revolutionary control approaches that can efficiently optimize aircraft performance in both normal and failure conditions and advancement of neural-network-based flight control technology for new aerospace system designs. This report presents an overview of the processes utilized to develop adaptive controller algorithms during a flight-test program, including a description of initial adaptive controller concepts and a discussion of modeling formulation and performance testing. Design finalization led to integration with the system interfaces, verification of the software, validation of the hardware to the requirements, design of failure detection, development of safety limiters to minimize the effect of erroneous neural network commands, and creation of flight test control room displays to maximize human situational awareness; these are also discussed.

  3. A Submaximal Running Test With Postexercise Cardiac Autonomic and Neuromuscular Function in Monitoring Endurance Training Adaptation.

    PubMed

    Vesterinen, Ville; Nummela, Ari; Laine, Tanja; Hynynen, Esa; Mikkola, Jussi; Häkkinen, Keijo

    2017-01-01

    Vesterinen, V, Nummela, A, Laine, T, Hynynen, E, Mikkola, J, and Häkkinen, K. A submaximal running test with postexercise cardiac autonomic and neuromuscular function in monitoring endurance training adaptation. J Strength Cond Res 31(1): 233-243, 2017-The aim of this study was to investigate whether a submaximal running test (SRT) with postexercise heart rate recovery (HRR), heart rate variability (HRV), and countermovement jump (CMJ) measurements could be used to monitor endurance training adaptation. Thirty-five endurance-trained men and women completed an 18-week endurance training. Maximal endurance performance and maximal oxygen uptake were measured every 8 weeks. In addition, SRTs with postexercise HRR, HRV, and CMJ measurements were carried out every 4 weeks. Submaximal running test consisted of two 6-minute stages at 70 and 80% of maximum heart rate (HRmax) and a 3-minute stage at 90% HRmax, followed by a 2-minute recovery stage for measuring postexercise HRR, HRV, and CMJ test. The highest responders according to the change of maximal endurance performance showed a significant improvement in running speeds during stages 2 and 3 in SRT, whereas no changes were observed in the lowest responders. The strongest correlation was found between the change of maximal endurance performance and running speed during stage 3, whereas no significant relationships were found between the change of maximal endurance performance and the changes of postexercise HRR, HRV, and CMJ. Running speed at 90% HRmax intensity was the most sensitive variable to monitor adaptation to endurance training. The present submaximal test showed potential to monitor endurance training adaptation. Furthermore, it may serve as a practical tool for athletes and coaches to evaluate weekly the effectiveness of training program without interfering in the normal training habits.

  4. Computer-Adaptive Testing for Students with Disabilities: A Review of the Literature. Research Report. ETS RR-11-32

    ERIC Educational Resources Information Center

    Stone, Elizabeth; Davey, Tim

    2011-01-01

    There has been an increased interest in developing computer-adaptive testing (CAT) and multistage assessments for K-12 accountability assessments. The move to adaptive testing has been met with some resistance by those in the field of special education who express concern about routing of students with divergent profiles (e.g., some students with…

  5. Grain trapping by filamentous cyanobacterial and algal mats: implications for stromatolite microfabrics through time.

    PubMed

    Frantz, C M; Petryshyn, V A; Corsetti, F A

    2015-09-01

    Archean and Proterozoic stromatolites are sparry or fine-grained and finely laminated; coarse-grained stromatolites, such as many found in modern marine systems, do not appear until quite late in the fossil record. The cause of this textural change and its relevance to understanding the evolutionary history of stromatolites is unclear. Cyanobacteria are typically considered the dominant stromatolite builders through time, but studies demonstrating the trapping and binding abilities of cyanobacterial mats are limited. With this in mind, we conducted experiments to test the grain trapping and binding capabilities of filamentous cyanobacterial mats and trapping in larger filamentous algal mats in order to better understand grain size trends in stromatolites. Mats were cut into squares, inclined in saltwater tanks at angles from 0 to 75° (approximating the angle of lamina in typical stromatolites), and grains of various sizes (fine sand, coarse sand, and fine pebbles) were delivered to their surface. Trapping of grains by the cyanobacterial mats depended strongly on (i) how far filaments protruded from the sediment surface, (ii) grain size, and (iii) the mat's incline angle. The cyanobacterial mats were much more effective at trapping fine grains beyond the abiotic slide angle than larger grains. In addition, the cyanobacterial mats actively bound grains of all sizes over time. In contrast, the much larger algal mats trapped medium and coarse grains at all angles. Our experiments suggest that (i) the presence of detrital grains beyond the abiotic slide angle can be considered a biosignature in ancient stromatolites where biogenicity is in question, and, (ii) where coarse grains are present within stromatolite laminae at angles beyond the abiotic angle of slide (e.g., most modern marine stromatolites), typical cyanobacterial-type mats are probably not solely responsible for the construction, giving insight into the evolution of stromatolite microfabrics through time.

  6. Adapting and Testing the COAMPS/COBEL Low Cloud Nowcasting System for Winter Conditions

    DTIC Science & Technology

    2001-09-30

    Adapting and Testing the COAMPS/ COBEL Low Cloud Nowcasting System for Winter Conditions Professor Peter Zwack, Earth and Atmospheric Sciences...514-987-7749 email: zwack.peter@uqam.ca Award Number: N00014-01-1-0377 http://people.sca.uqam.ca/~ cobel /COTE_EST/ http://people.sca.uqam.ca...tardif/ COBEL /cobel_enter.htm LONG-TERM GOALS An improved an automated, globally applicable, integrated ceiling forecast product in DAMPS that

  7. Aeroelastic Deformation: Adaptation of Wind Tunnel Measurement Concepts to Full-Scale Vehicle Flight Testing

    NASA Technical Reports Server (NTRS)

    Burner, Alpheus W.; Lokos, William A.; Barrows, Danny A.

    2005-01-01

    The adaptation of a proven wind tunnel test technique, known as Videogrammetry, to flight testing of full-scale vehicles is presented. A description is presented of the technique used at NASA's Dryden Flight Research Center for the measurement of the change in wing twist and deflection of an F/A-18 research aircraft as a function of both time and aerodynamic load. Requirements for in-flight measurements are compared and contrasted with those for wind tunnel testing. The methodology for the flight-testing technique and differences compared to wind tunnel testing are given. Measurement and operational comparisons to an older in-flight system known as the Flight Deflection Measurement System (FDMS) are presented.

  8. Flight Test of L1 Adaptive Control Law: Offset Landings and Large Flight Envelope Modeling Work

    NASA Technical Reports Server (NTRS)

    Gregory, Irene M.; Xargay, Enric; Cao, Chengyu; Hovakimyan, Naira

    2011-01-01

    This paper presents new results of a flight test of the L1 adaptive control architecture designed to directly compensate for significant uncertain cross-coupling in nonlinear systems. The flight test was conducted on the subscale turbine powered Generic Transport Model that is an integral part of the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. The results presented include control law evaluation for piloted offset landing tasks as well as results in support of nonlinear aerodynamic modeling and real-time dynamic modeling of the departure-prone edges of the flight envelope.

  9. Immobility in the forced swim test is adaptive and does not reflect depression.

    PubMed

    Molendijk, Marc L; de Kloet, E Ronald

    2015-12-01

    The forced swim test is based on the progressive immobility a rodent displays when immersed in a beaker filled with water from where no escape is possible. While the test was originally designed to identify the antidepressant potential of drugs, over the past decade a rapidly growing number of publications (more than 2000) portray this immobility response anthropomorphically as a measure for depression and despair. This is incorrect. The response to the forced swim stressor should be considered for what it shows: a switch from active to passive behavior in the face of an acute stressor, aligned to cognitive functions underlying behavioral adaptation and survival.

  10. Adaptive and Qualitative Changes in Encoding Strategy With Experience: Evidence From the Test-Expectancy Paradigm

    PubMed Central

    Finley, Jason R.; Benjamin, Aaron S.

    2012-01-01

    Three experiments demonstrated learners’ abilities to adaptively and qualitatively accommodate their encoding strategies to the demands of an upcoming test. Stimuli were word pairs. In Experiment 1, test expectancy was induced for either cued recall (of targets given cues) or free recall (of targets only) across 4 study–test cycles of the same test format, followed by a final critical cycle featuring either the expected or the unexpected test format. For final tests of both cued and free recall, participants who had expected that test format outperformed those who had not. This disordinal interaction, supported by recognition and self-report data, demonstrated not mere differences in effort based on anticipated test difficulty, but rather qualitative and appropriate differences in encoding strategies based on expected task demands. Participants also came to appropriately modulate metacognitive monitoring (Experiment 2) and study-time allocation (Experiment 3) across study–test cycles. Item and associative recognition performance, as well as self-report data, revealed shifts in encoding strategies across trials; these results were used to characterize and evaluate the different strategies that participants employed for cued versus free recall and to assess the optimality of participants’ metacognitive control of encoding strategies. Taken together, these data illustrate a sophisticated form of metacognitive control, in which learners qualitatively shift encoding strategies to match the demands of anticipated tests. PMID:22103783

  11. Adaptive and qualitative changes in encoding strategy with experience: evidence from the test-expectancy paradigm.

    PubMed

    Finley, Jason R; Benjamin, Aaron S

    2012-05-01

    Three experiments demonstrated learners' abilities to adaptively and qualitatively accommodate their encoding strategies to the demands of an upcoming test. Stimuli were word pairs. In Experiment 1, test expectancy was induced for either cued recall (of targets given cues) or free recall (of targets only) across 4 study-test cycles of the same test format, followed by a final critical cycle featuring either the expected or the unexpected test format. For final tests of both cued and free recall, participants who had expected that test format outperformed those who had not. This disordinal interaction, supported by recognition and self-report data, demonstrated not mere differences in effort based on anticipated test difficulty, but rather qualitative and appropriate differences in encoding strategies based on expected task demands. Participants also came to appropriately modulate metacognitive monitoring (Experiment 2) and study-time allocation (Experiment 3) across study-test cycles. Item and associative recognition performance, as well as self-report data, revealed shifts in encoding strategies across trials; these results were used to characterize and evaluate the different strategies that participants employed for cued versus free recall and to assess the optimality of participants' metacognitive control of encoding strategies. Taken together, these data illustrate a sophisticated form of metacognitive control, in which learners qualitatively shift encoding strategies to match the demands of anticipated tests.

  12. Exaptation in human evolution: how to test adaptive vs exaptive evolutionary hypotheses.

    PubMed

    Pievani, Telmo; Serrelli, Emanuele

    2011-01-01

    Palaeontologists, Stephen J. Gould and Elisabeth Vrba, introduced the term "ex-aptation" with the aim of improving and enlarging the scientific language available to researchers studying the evolution of any useful character, instead of calling it an "adaptation" by default, coming up with what Gould named an "extended taxonomy of fitness". With the extension to functional co-optations from non-adaptive structures ("spandrels"), the notion of exaptation expanded and revised the neo-Darwinian concept of "pre-adaptation" (which was misleading, for Gould and Vrba, suggesting foreordination). Exaptation is neither a "saltationist" nor an "anti-Darwinian" concept and, since 1982, has been adopted by many researchers in evolutionary and molecular biology, and particularly in human evolution. Exaptation has also been contested. Objections include the "non-operationality objection".We analyze the possible operationalization of this concept in two recent studies, and identify six directions of empirical research, which are necessary to test "adaptive vs. exaptive" evolutionary hypotheses. We then comment on a comprehensive survey of literature (available online), and on the basis of this we make a quantitative and qualitative evaluation of the adoption of the term among scientists who study human evolution. We discuss the epistemic conditions that may have influenced the adoption and appropriate use of exaptation, and comment on the benefits of an "extended taxonomy of fitness" in present and future studies concerning human evolution.

  13. AM2 Brickwork Pattern Evaluation with Refurbished Matting

    DTIC Science & Technology

    2015-08-01

    and Jeb S. Tingle Geotechnical and Structures Laboratory U.S. Army Engineer Research and Development Center 3909 Halls Ferry Road Vicksburg, MS ...Waterways Experiment Station in Vicksburg, MS from 1961 through 1971, with major procurements beginning in 1965. The original AM2 mat has been modified...from a local source in Vicksburg, MS , and was subjected to laboratory tests including grain-size analysis (hydrometer), Atterberg Limits, modified

  14. Initial adaptation testing of the bidimensionally self-adapting wall of the French T2 wind tunnel, around a three-dimensional object

    NASA Technical Reports Server (NTRS)

    Archambaud, J. P.; Dor, J. B.; Mignosi, A.; Lamarche, L.

    1986-01-01

    The test series was carried out at ONERA/CERT at the T2 wind tunnel in September 1984. The objective of this series was to minimize wall interference through a bidimensional adaptation around the models, inducing tridimensional flows. For this, three different models were used, measuring either the pressures or the forces and moment of pitch (balance). The adaptation was derived from a correction computation in the compressible axisymmetric tridimensional.

  15. Translation, cultural adaptation and field-testing of the Thinking Healthy Program for Vietnam

    PubMed Central

    2014-01-01

    Background Depression and anxiety are prevalent among women in low- and lower-middle income countries who are pregnant or have recently given birth. There is promising evidence that culturally-adapted, evidence-informed, perinatal psycho-educational programs implemented in local communities are effective in reducing mental health problems. The Thinking Healthy Program (THP) has proved effective in Pakistan. The aims were to adapt the THP for rural Vietnam; establish the program’s comprehensibility, acceptability and salience for universal use, and investigate whether administration to small groups of women might be of equivalent effectiveness to administration in home visits to individual women. Methods The THP Handbook and Calendar were made available in English by the program developers and translated into Vietnamese. Cultural adaptation and field-testing were undertaken using WHO guidance. Field-testing of the four sessions of THP Module One was undertaken in weekly sessions with a small group in a rural commune and evaluated using baseline, process and endline surveys. Results The adapted Vietnamese version of the Thinking Healthy Program (THP-V) was found to be understandable, meaningful and relevant to pregnant women, and commune health centre and Women’s Union representatives in a rural district. It was delivered effectively by trained local facilitators. Role-play, brainstorming and small-group discussions to find shared solutions to common problems were appraised as helpful learning opportunities. Conclusions The THP-V is safe and comprehensible, acceptable and salient to pregnant women without mental health problems in rural Vietnam. Delivery in facilitated small groups provided valued opportunities for role-play rehearsal and shared problem solving. Local observers found the content and approach highly relevant to local needs and endorsed the approach as a mental health promotion strategy with potential for integration into local universal maternal

  16. Effect of sticky mat usage in control of nosocomial infection in Motahary Burn Hospital

    PubMed Central

    Dahmardehei, Mostafa; Alinejad, Faranak; Ansari, Fereshteh; Bahramian, Mahnaz; Barati, Mitra

    2016-01-01

    Background and Objectives: Infection is the most common cause of death among burnt patients and infection control decrease the rate of mortality. The use of sticky mat can control contamination by preventing the entrance microorganisms into the hospital wards. This study was designed to evaluate the sticky mats effect in reduction of microorganism’s entry by personnel shoes to burn intensive care unit (BICU). Materials and Methods: This is a simple cross sectional study. We tested outer soles of personnel’s shoes with swap and cultured them before and after sticky mat contact in the entrance of BICU. Results were analyzed with IBM SPSS version 22 software. McNemar and Wilcoxon Signed Ranks tests were used. Results: We analyzed 60 outer soles of the shoes before and after contact with sticky mats. Coagulase negative Staphylococci, Gram positive bacilli, Staphylococcus aureus, Aspergillus fumigatus, Pseudomonas aeruginosa and Acinetobacter baumannii were isolated before contact from 57 (95%), 32 (53%), 4 (6.7%) and 3 (5%) cases, respectively. Coagulase negative Staphylococci, Gram positive bacilli, Staphylococcus aureus, Aspergillus fumigatus, Pseudomonas aeruginosa were isolated after contact from 36 (60%), 30 (50%), 16 (26.6%), 2 (3.3%) and 3 (5%) cases, respectively. No Acinetobacter was isolated after contact with sticky mat. Total isolated colonies before and after contact with sticky mats were 2573 and 830, respectively. There were significant statistically differences between the colony counts of coagulase ngative staphylococci, Gram positive bacilli, and Staphylococci aureus before and after contact with sticky mats (P. < 0.001). Conclusion: Regarding to statistical analysis, the effect of mat in removing the microorganisms was 56%. It confirms the effectiveness of sticky mat controlling the infection and reducing the amount of hospital contamination. PMID:27928489

  17. Sulfate-reducing bacteria and their activities in cyanobacterial mats of Solar Lake (Sinai, Egypt)

    SciTech Connect

    Teske, A.; Ramsing, N.B.; Habicht, K.; Kuever, J.; Joergensen, B.B.; Fukui, Manabu; Cohen, Y.

    1998-08-01

    The sulfate-reducing bacteria within the surface layer of the hypersaline cyanobacterial mat of Solar Lake (Sinai, Egypt) were investigated with combined microbiological, molecular, and biogeochemical approaches. The diurnally oxic surface layer contained between 10{sup 6} and 10{sup 7} cultivable sulfate-reducing bacteria ml{sup {minus}1} day{sup {minus}1}, both in the same range as and sometimes higher than those in anaerobic deeper mat layers. In the oxic surface layer and in the mat layers below, filamentous sulfate-reducing Desulfonema bacteria were found in variable densities of 10{sup 4} and 10{sup 6} cells ml{sup {minus}1}. A Desulfonema-related, diurnally migrating bacterium was detected with PCR and denaturing gradient gel electrophoresis within and below the oxic surface layer. Facultative aerobic respiration, filamentous morphology, motility, diurnal migration, and aggregate formation were the most conspicuous adaptations of Solar Lake sulfate-reducing bacteria to the mat matrix and to diurnal oxygen stress. A comparison of sulfate reduction rates within the mat and previously published photosynthesis rates showed that CO{sub 2} from sulfate reduction in the upper 5 mm accounted for 7 to 8% of the total photosynthetic CO{sub 2} demand of the mat.

  18. Using Tests Designed to Measure Individual Sensorimotor Subsystem Perfomance to Predict Locomotor Adaptability

    NASA Technical Reports Server (NTRS)

    Peters, B. T.; Caldwell, E. E.; Batson, C. D.; Guined, J. R.; DeDios, Y. E.; Stepanyan, V.; Gadd, N. E.; Szecsy, D. L.; Mulavara, A. P.; Seidler, R. D.; Bloomberg, J. J.

    2014-01-01

    Astronauts experience sensorimotor disturbances during the initial exposure to microgravity and during the readapation phase following a return to a gravitational environment. These alterations may lead to disruption in the ability to perform mission critical functions during and after these gravitational transitions. Astronauts show significant inter-subject variation in adaptive capability following gravitational transitions. The way each individual's brain synthesizes the available visual, vestibular and somatosensory information is likely the basis for much of the variation. Identifying the presence of biases in each person's use of information available from these sensorimotor subsystems and relating it to their ability to adapt to a novel locomotor task will allow us to customize a training program designed to enhance sensorimotor adaptability. Eight tests are being used to measure sensorimotor subsystem performance. Three of these use measures of body sway to characterize balance during varying sensorimotor challenges. The effect of vision is assessed by repeating conditions with eyes open and eyes closed. Standing on foam, or on a support surface that pitches to maintain a constant ankle angle provide somatosensory challenges. Information from the vestibular system is isolated when vision is removed and the support surface is compromised, and it is challenged when the tasks are done while the head is in motion. The integration and dominance of visual information is assessed in three additional tests. The Rod & Frame Test measures the degree to which a subject's perception of the visual vertical is affected by the orientation of a tilted frame in the periphery. Locomotor visual dependence is determined by assessing how much an oscillating virtual visual world affects a treadmill-walking subject. In the third of the visual manipulation tests, subjects walk an obstacle course while wearing up-down reversing prisms. The two remaining tests include direct

  19. Fabrication and Testing of Active and Adaptive Cyanate Ester Composite Mirrors

    NASA Technical Reports Server (NTRS)

    Bennett, H. E.

    2004-01-01

    The objective of the NASA/Bennett Optical Research Inc. (BOR) NAS8-02008 Phase II Program, which also incorporated ideas developed under the earlier NASA NAS8-01035 Phase 1 Program, was to develop a large mirror fabrication and test facility with emphasis on producing large, light weight active and adaptive optics. A principle objective was to develop mandrels on which to make large composite graphite-filled cyanate ester mirrors, Deliverables were two of these superpolished lightweight active/adaptive optic composite mirrors, one 12" (approx.1/3 meter) in diameter and one 22" (approx.1/2 meter) in diameter. In addition optical superpolishers for mandrels up to 1.2 meters in diameter, test instruments for determining optical figure and scattered light, novel design actuators for making the composite mirrors both active and adaptive, and passive and active means for measuring actuator performance were developed at BOR. We are now installing a superpolisher capable of producing 3 meter diameter mirror/mandrels. All polishers utilize the principle of centrifugal elutriation and produce superpolished mandrels with surface microroughnesses under 1 nm rms.

  20. Cyanobacterial mats: Microanalysis of community metabolism

    NASA Technical Reports Server (NTRS)

    Cohen, Y.; Bermudes, D.; Fischer, U.; Haddad, R.; Prufert, L.; Scheulderman-Suylen, T.; Shaw, T.

    1985-01-01

    The microbial communities in two sites were studied using several approaches: (1) light microscopy; (2) the measurement of microprofiles of oxygen and sulfide at the surface of the microbial mat; (3) the study of diurnal variation of oxygen and sulfides; (4) in situ measurement of photosynthesis and sulfate reduction and study of the coupling of these two processes; (5) measurement of glutathione in the upper layers of the microbial mat as a possible oxygen quencher; (6) measurement of reduced iron as a possible intermediate electron donor along the established redoxcline in the mats; (7) measurement of dissolved phosphate as an indicator of processes of break down of organic matter in these systems; and (8) measurement of carbon dioxide in the interstitial water and its delta C-13 in an attempt to understand the flow of CO2 through the systems. Microbial processes of primary production and initial degradation at the most active zone of the microbial mat were analyzed.

  1. PHURBAS: AN ADAPTIVE, LAGRANGIAN, MESHLESS, MAGNETOHYDRODYNAMICS CODE. II. IMPLEMENTATION AND TESTS

    SciTech Connect

    McNally, Colin P.; Mac Low, Mordecai-Mark; Maron, Jason L. E-mail: jmaron@amnh.org

    2012-05-01

    We present an algorithm for simulating the equations of ideal magnetohydrodynamics and other systems of differential equations on an unstructured set of points represented by sample particles. The particles move with the fluid, so the time step is not limited by the Eulerian Courant-Friedrichs-Lewy condition. Full spatial adaptivity is required to ensure the particles fill the computational volume and gives the algorithm substantial flexibility and power. A target resolution is specified for each point in space, with particles being added and deleted as needed to meet this target. We have parallelized the code by adapting the framework provided by GADGET-2. A set of standard test problems, including 10{sup -6} amplitude linear magnetohydrodynamics waves, magnetized shock tubes, and Kelvin-Helmholtz instabilities is presented. Finally, we demonstrate good agreement with analytic predictions of linear growth rates for magnetorotational instability in a cylindrical geometry. This paper documents the Phurbas algorithm as implemented in Phurbas version 1.1.

  2. Experimental characterization of an adaptive aileron: lab tests and FE correlation

    NASA Astrophysics Data System (ADS)

    Amendola, Gianluca; Dimino, Ignazio; Amoroso, Francesco; Pecora, Rosario

    2016-04-01

    Like any other technology, morphing has to demonstrate system level performance benefits prior to implementation onto a real aircraft. The current status of morphing structures research efforts (as the ones, sponsored by the European Union) involves the design of several subsystems which have to be individually tested in order to consolidate their general performance in view of the final integration into a flyable device. This requires a fundamental understanding of the interaction between aerodynamic, structure and control systems. Important worldwide research collaborations were born in order to exchange acquired experience and better investigate innovative technologies devoted to morphing structures. The "Adaptive Aileron" project represents a joint cooperation between Canadian and Italian research centers and leading industries. In this framework, an overview of the design, manufacturing and testing of a variable camber aileron for a regional aircraft is presented. The key enabling technology for the presented morphing aileron is the actuation structural system, integrating a suitable motor and a load-bearing architecture. The paper describes the lab test campaign of the developed device. The implementation of a distributed actuation system fulfills the actual tendency of the aeronautical research to move toward the use of electrical power to supply non-propulsive systems. The aileron design features are validated by targeted experimental tests, demonstrating both its adaptive capability and robustness under operative loads and its dynamic behavior for further aeroelastic analyses. The experimental results show a satisfactory correlation with the numerical expectations thus validating the followed design approach.

  3. A global logrank test for adaptive treatment strategies based on observational studies.

    PubMed

    Li, Zhiguo; Valenstein, Marcia; Pfeiffer, Paul; Ganoczy, Dara

    2014-02-28

    In studying adaptive treatment strategies, a natural question that is of paramount interest is whether there is any significant difference among all possible treatment strategies. When the outcome variable of interest is time-to-event, we propose an inverse probability weighted logrank test for testing the equivalence of a fixed set of pre-specified adaptive treatment strategies based on data from an observational study. The weights take into account both the possible selection bias in an observational study and the fact that the same subject may be consistent with more than one treatment strategy. The asymptotic distribution of the weighted logrank statistic under the null hypothesis is obtained. We show that, in an observational study where the treatment selection probabilities need to be estimated, the estimation of these probabilities does not have an effect on the asymptotic distribution of the weighted logrank statistic, as long as the estimation of the parameters in the models for these probabilities is n-consistent. Finite sample performance of the test is assessed via a simulation study. We also show in the simulation that the test can be pretty robust to misspecification of the models for the probabilities of treatment selection. The method is applied to analyze data on antidepressant adherence time from an observational database maintained at the Department of Veterans Affairs' Serious Mental Illness Treatment Research and Evaluation Center.

  4. Improved Testing Capability and Adaptability Through the Use of Wireless Sensors

    NASA Technical Reports Server (NTRS)

    Solano, Wanda M.

    2003-01-01

    From the first Saturn V rocket booster (S-II-T) testing in 1966 and the routine Space Shuttle Main Engine (SSME) testing beginning in 1975, to more recent test programs such as the X-33 Aerospike Engine, the Integrated Powerhead Development (IPD) program, and the Hybrid Sounding Rocket (HYSR), Stennis Space Center (SSC) continues to be a premier location for conducting large-scale testing. Central to each test program is the capability for sensor systems to deliver reliable measurements and high quality data, while also providing a means to monitor the test stand area to the highest degree of safety and sustainability. Sensor wiring is routed along piping and through cable trenches, making its way from the engine test area, through the test stand area and to the signal conditioning building before final transfer to the test control center. When sensor requirements lie outside the reach of the routine sensor cable routing, the use of wireless sensor networks becomes particularly attractive due to their versatility and ease of installation. As part of an on-going effort to enhance the testing capabilities of Stennis Space Center, the Test Technology and Development group has found numerous applications for its sensor-adaptable wireless sensor suite. While not intended for critical engine measurements or control loops, in-house hardware and software development of the sensor suite can provide improved testing capability for a range of applications including the safety monitoring of propellant storage barrels and as an experimental test-bed for embedded health monitoring paradigms.

  5. Nonwoven filtration mat production by electrospinning method

    NASA Astrophysics Data System (ADS)

    Lackowski, M.; Krupa, A.; Jaworek, A.

    2011-06-01

    The filtration of nanoparticles and submicron particles is an important problem in industry and health protection. One of the methods which can be used to solve this problem is to use nonwoven nanofibrous filters. The process of producing filtration mats of different thickness by electrospinning is presented in the paper. The experimental results on filtration properties of nanofibrous filter mat, including the efficiency of removal of cigarette smoke particles from a gas are also presented.

  6. Design and Flight Tests of an Adaptive Control System Employing Normal-Acceleration Command

    NASA Technical Reports Server (NTRS)

    McNeill, Water E.; McLean, John D.; Hegarty, Daniel M.; Heinle, Donovan R.

    1961-01-01

    An adaptive control system employing normal-acceleration command has been designed with the aid of an analog computer and has been flight tested. The design of the system was based on the concept of using a mathematical model in combination with a high gain and a limiter. The study was undertaken to investigate the application of a system of this type to the task of maintaining nearly constant dynamic longitudinal response of a piloted airplane over the flight envelope without relying on air data measurements for gain adjustment. The range of flight conditions investigated was between Mach numbers of 0.36 and 1.15 and altitudes of 10,000 and 40,000 feet. The final adaptive system configuration was derived from analog computer tests, in which the physical airplane control system and much of the control circuitry were included in the loop. The method employed to generate the feedback signals resulted in a model whose characteristics varied somewhat with changes in flight condition. Flight results showed that the system limited the variation in longitudinal natural frequency of the adaptive airplane to about half that of the basic airplane and that, for the subsonic cases, the damping ratio was maintained between 0.56 and 0.69. The system also automatically compensated for the transonic trim change. Objectionable features of the system were an exaggerated sensitivity of pitch attitude to gust disturbances, abnormally large pitch attitude response for a given pilot input at low speeds, and an initial delay in normal-acceleration response to pilot control at all flight conditions. The adaptive system chatter of +/-0.05 to +/-0.10 of elevon at about 9 cycles per second (resulting in a maximum airplane normal-acceleration response of from +/-0.025 g to +/- 0.035 g) was considered by the pilots to be mildly objectionable but tolerable.

  7. Item Selection in Computerized Adaptive Testing: Improving the a-Stratified Design with the Sympson-Hetter Algorithm

    ERIC Educational Resources Information Center

    Leung, Chi-Keung; Chang, Hua-Hua; Hau, Kit-Tai

    2002-01-01

    Item exposure control, test-overlap minimization, and the efficient use of item pool are some of the important issues in computerized adaptive testing (CAT) designs. The overexposure of some items and high test-overlap rate may cause both item and test security problems. Previously these problems associated with the maximum information (Max-I)…

  8. Adaptation of IFN-gamma ELISA and ELISPOT tests for feline tuberculosis.

    PubMed

    Rhodes, Shelley G; Gruffydd-Jones, Tim; Gunn-Moore, Danièlle; Jahans, Keith

    2008-08-15

    There are currently no reliable immunodiagnostic tests for feline tuberculosis. Infection of domestic cats in the UK is thought to occur via their contact with the relevant reservoir of infection, e.g. cattle and badgers for Mycobacterium bovis, and rodents for M. microti. In the African National Parks, where M. bovis infection of Bovidae is an increasing problem, transmission to big cats is occurring via their ingestion of infected carcasses. We have adapted feline ELISA and ELISPOT assays to potentially provide the first cell-based diagnostic test for the detection of tuberculosis in cats. We tested peripheral blood mononuclear cell antigen-specific IFN-gamma responses of 18 cats suspected of mycobacterial infection for which biopsy material was co-submitted to the Veterinary Laboratories Agency for mycobacterial culture and identification. Seventeen cats were tested by ELISA while seven cats were tested by ELISPOT (six cats were tested by both ELISA and ELISPOT). Six healthy control cats provided baseline data for these tests. Responses to bovine and avian tuberculins (PPDB and PPDA) and a protein cocktail of ESAT6 and CFP10 were measured, together with positive mitogen (PMA and calcium ionophore) and negative (medium) controls. Overall, both ELISPOT and ELISA tests were found to be suitable for generating rapid results (2 and 4 days, respectively), which provided good predictive information for M. bovis and M. microti infections, but were unable to reliably discern M. avium infection.

  9. A Cross-Cultural Adaptation of the Sniffin' Sticks Olfactory Identification Test for US children.

    PubMed

    Cavazzana, Annachiara; Wesarg, Christiane; Schriever, Valentin A; Hummel, Thomas; Lundström, Johan N; Parma, Valentina

    2017-02-01

    Disorders associated with smell loss are common in adolescents. However, current odor identification tests focus on children from age 6 and older and no cross-cultural test has to date been validated and fully implemented. Here, we aimed to investigate how 3-to-11-year-old US children performed to an adapted and shortened (11 odors instead of 14) version of a European odor identification test-the Sniffin' Kids (Schriever VA, Mori E, Petters W, Boerner C, Smitka M, Hummel T. 2014. The "Sniffin'Kids" test: a 14-item odor identification test for children. Plos One. 9:e101086.). Results confirmed that cued odor identification performance increases with age and revealed little to no differences between girls and boys. Scores below 3 and below 6 may raise hyposmia concerns in US children aged 3-7 years and 8-10 years, respectively. Even though the completion rate of the task reached the 88%, suggesting that children below age 5 were able to finish the test, their performance was relatively poor. In comparing the overall identification performance of US children with that of German children, for whom the test was specifically developed, significant differences emerged, with higher scores obtained by the German sample. Analysis of errors indicated that a lack of semantic knowledge for the olfactory-presented objects may be at the root of poor identification skills in US children and therefore constitutes a problem in the development of an odor identification test for younger children valid across cultures.

  10. Exploring defocus matting: nonparametric acceleration, super-resolution, and off-center matting.

    PubMed

    Joshi, Neel; Matusik, Wojciech; Avidan, Shai; Pfister, Hanspeter; Freeman, William T

    2007-01-01

    Defocus matting is a fully automatic and passive method for pulling mattes from video captured with coaxial cameras that have different depths of field and planes of focus. Nonparametric sampling can accelerate the video-matting process from minutes to seconds per frame. In addition a super-resolution technique efficiently bridges the gap between mattes from high-resolution video cameras and those from low-resolution cameras. Off-center matting pulls mattes for an external high-resolution camera that doesn't share the same center of projection as the low-resolution cameras used to capture the defocus matting data.

  11. Eukaryotes in Arctic and Antarctic cyanobacterial mats.

    PubMed

    Jungblut, Anne D; Vincent, Warwick F; Lovejoy, Connie

    2012-11-01

    Cyanobacterial mats are commonly found in freshwater ecosystems throughout the polar regions. Most mats are multilayered three-dimensional structures with the filamentous cyanobacteria embedded in a gel-like matrix. Although early descriptions mentioned the presence of larger organisms including metazoans living in the mats, there have been few studies specifically focused on the microbial eukaryotes, which are often small cells with few morphological features suitable for identification by microscopy. Here, we applied 18S rRNA gene clone library analysis to identify eukaryotes in cyanobacterial mat communities from both the Antarctic and the extreme High Arctic. We identified 39 ribotypes at the level of 99% sequence similarity. These consisted of taxa within algal and other protist groups including Chlorophyceae, Prasinophyceae, Ulvophyceae, Trebouxiophyceae, Bacillariophyceae, Chrysophyceae, Ciliophora, and Cercozoa. Fungi were also recovered, as were 21 metazoan ribotypes. The eukaryotic taxa appeared habitat-specific with little overlap between lake, pond, and ice shelf communities. Some ribotypes were common to both Arctic and Antarctic mats, suggesting global dispersal of these taxa and similarity in the environmental filters acting on protist communities. Many of these eukaryotic taxa likely benefit from protected, nutrient-rich microhabitats within the cyanobacterial mat environment.

  12. Growth, composition and metal removal potential of a Phormidium bigranulatum-dominated mat at elevated levels of cadmium.

    PubMed

    Kumar, Dhananjay; Yadav, Arpana; Gaur, J P

    2012-07-15

    Prompted by the fact that interaction of metals with cyanobacterial mats has been little studied, the present study evaluates the response of a cyanobacterial mat, dominated by Phormidium bigranulatum, to elevated concentrations of Cd²⁺ in the medium. The mat failed to grow at 7 μM of Cd²⁺ when the metal as also the mat inoculum were simultaneously added to the medium right in the beginning of the experiment due to marked sensitivity of P. bigranulatum, the main constituent of the mat, to high concentrations of Cd²⁺. However, the mat previously grown in Cd²⁺-free medium for a time period of 1-4 weeks grew successfully when exposed to media containing very high concentrations of Cd²⁺. Four-week-old mat could grow at 250 μM of Cd²⁺, which has been found toxic to many cyanobacteria and algae by previous researchers. Greater tolerance of older mats to Cd²⁺ may be due to greater proportion of exopolysaccharides, which are well known to sequester metal ions extracellularly, in them. Whereas the relative proportion of P. bigranulatum declined at high concentrations of the test metal that of green algae increased due most likely to their tolerance to Cd²⁺. Air bubbles were seen entrapped in the mat due obviously to photosynthetic activity. Elevated concentrations of Cd²⁺ reduced the number of air bubbles in the mat. Decline in number of air bubbles at high concentrations of metal ions was more prominent in the case of younger mat than in the older one. The present study also evaluated changes in species composition of mats of different age that were subsequently grown in Cd²⁺ enriched culture medium. Younger mats showed change in species composition at very low concentrations of Cd²⁺, but older mats showed little changes even at very high concentrations of the test metal. Hence older mats more strongly resisted to changes in its species composition than the younger ones upon exposure to high concentrations of Cd²⁺. The growing mat

  13. Estimation of axial stiffness of plant fibres from compaction of non-woven mats

    NASA Astrophysics Data System (ADS)

    Gamstedt, E. K.; Bommier, E.; Madsen, B.

    2014-03-01

    Plant fibres are known to show a large variability in stiffness, which makes it time-consuming to experimentally characterize this property by conventional tensile testing. In this work, an alternative method is used, where the average fibre stiffness is back-calculated from compaction tests of in-plane randomly oriented fibre mats. The model by Toll is used to relate the load-displacement curve from the test to the Young modulus of the fibre, taking into account the natural variability in fibre cross section. Several tests have been performed on hemp fibre mats and compared with results from single-fibre tensile testing. The average back-calculated Young's modulus of the fibres was 45 GPa, whereas the average value from tensile testing ranged from 30 to 60 GPa. The straightforward compaction test can be useful in ranking of fibre stiffness, provided that the mat is composed of well-separated fibres and not of twisted yarns.

  14. Flow visualization study of the HiMAT RPRV

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1980-01-01

    Water tunnel studies were performed to qualitatively define the flow field of the highly maneuverable aircraft technology remotely piloted research vehicle (HiMAT RPRV). Particular emphasis was placed on defining the vortex flows generated at high angles of attack. The flow visualization tests were conducted in the Northrop water tunnel using a 1/15 scale model of the HiMAT RPRV. Flow visualization photographs were obtained for angles of attack up to 40 deg and sideslip angles up to 5 deg. The HiMAT model was investigated in detail to determine the canard and wing vortex flow field development, vortex paths, and vortex breakdown characteristics as a function of angle of attack and sideslip. The presence of the canard caused the wing vortex to form further outboard and delayed the breakdown of the wing vortex to higher angles of attack. An increase in leading edge camber of the maneuver configuration delayed both the formation and the breakdown of the wing and canard vortices. Additional tests showed that the canard vortex was sensitive to variations in inlet mass flow ratio and canard flap deflection angle.

  15. Adaptation of the cellscan technique for the SCM test in breast cancer.

    PubMed

    Rahmani, H; Deutsch, M; Ron, I; Gerbat, S; Tirosh, R; Weinreb, A; Chaitchik, S; Lalchuk, S

    1996-09-01

    The value of the SCM (Structuredness of Cytoplasmic Matrix) cancer test, a procedure based on the detection of differences in lymphocyte activation in the presence and absence of cancer, has remained controversial, with inconsistent results having been reported among investigators. The Cellscan, a high-precision static cytometer system, has been designed to perform the SCM test; the apparatus facilitates the polarisation measurements and can examine cells which have been separated by simpler procedures than were originally described. In this study, using methods and diagnostic criteria adapted for the Cellscan system in a hospital environment, the SCM test correctly classified over 90% (76/80) of patients with breast cancer and differentiated over 90% (72/73) of individuals without cancer.

  16. Putting Out the Welcome Mat

    ERIC Educational Resources Information Center

    Glazzard, Peggy

    1977-01-01

    In anticipation of adjustments regular class teachers will have to make as mainstreaming proceeds under the Education for All Handicapped Children Act, the author offers guidelines on welcoming and adapting teaching methods for handicapped learners. Available from: Allen Raymond, Inc., P.O. Box 1223, Darien, Connecticut 06820. (GW)

  17. The transition of the national certification examination from paper and pencil to computer adaptive testing.

    PubMed

    Zaglaniczny, K L

    1996-02-01

    The Council on Certification of Nurse Anesthetists (CCNA) has been exploring computerized adaptive testing (CAT) for the national certification examination (NCE) over the past several years. CCNA representatives have consulted with experts in testing and with individuals from professional associations who use CAT for certification or licensure testing. This article will provide an overview of CAT and discuss how the CCNA plans to implement CAT for the NCE beginning April 8, 1996. A future article that explains the theoretical concepts of CAT will be published in the April 1996 AANA Journal. It is important to note that the NCE will not be a new test, the current content outline and item bank will remain the same. It is only the method of test administration that is changed--from paper and pencil to CAT. Each candidate will answer questions and take a test that is individualized to his or her ability or competence level and meets the specifications of the test outline. All candidates must achieve the same passing score. The implementation of CAT for the NCE will be advantageous for the candidates and provide a more efficient competency assessment. The last paper and pencil examination was administered on December 9, 1995. The transition is a significant event in nurse anesthesia history, just as nurse anesthesia was the first advanced practice nursing specialty to implement the certification credential, the CCNA will be the first to introduce CAT.

  18. Implementation of an Adaptive Controller System from Concept to Flight Test

    NASA Technical Reports Server (NTRS)

    Larson, Richard R.; Burken, John J.; Butler, Bradley S.

    2009-01-01

    The National Aeronautics and Space Administration Dryden Flight Research Center (Edwards, California) is conducting ongoing flight research using adaptive controller algorithms. A highly modified McDonnell-Douglas NF-15B airplane called the F-15 Intelligent Flight Control System (IFCS) was used for these algorithms. This airplane has been modified by the addition of canards and by changing the flight control systems to interface a single-string research controller processor for neural network algorithms. Research goals included demonstration of revolutionary control approaches that can efficiently optimize aircraft performance for both normal and failure conditions, and to advance neural-network-based flight control technology for new aerospace systems designs. Before the NF-15B IFCS airplane was certified for flight test, however, certain processes needed to be completed. This paper presents an overview of these processes, including a description of the initial adaptive controller concepts followed by a discussion of modeling formulation and performance testing. Upon design finalization, the next steps are: integration with the system interfaces, verification of the software, validation of the hardware to the requirements, design of failure detection, development of safety limiters to minimize the effect of erroneous neural network commands, and creation of flight test control room displays to maximize human situational awareness.

  19. Development and field testing of a 15-kv class adaptive var compensator

    SciTech Connect

    El-Sharkawi, M.A.; Dong, M.; Huang, T.; Szofran, A.; Andexler, G.; Venkata, S.S.; Butler, N.; Rodriguez, A.; Kerszenbaum

    1995-10-01

    A 15-kV class Adaptive Var Compensator (AVC) is developed and field tested. The AVC is a solid stat switched, binary stepped capacitor bank, used to compensate any rapidly changing reactive demand within one-half cycle without introducing transients of harmonics. The main features of the AVC are introduced followed by an historical evolution. A general description of each major module is presented and modifications as development proceeded are shown. Results from two industrial site installations are also presented showing the adverse conditions in which the AVC will successfully operate.

  20. Testing Refinement Criteria in Adaptive Discontinuous Galerkin Simulations of Dry Atmospheric Convection

    DTIC Science & Technology

    2011-12-22

    Testing refinement criteria in adaptive Discontinuous Galerkin simulations of dry atmospheric convection Andreas Müllera,∗, Jörn Behrensb, Francis X...mainz.de (Andreas Müller), joern.behrens@zmaw.de (Jörn Behrens), fxgirald@nps.edu ( Francis X. Giraldo), vwirth@uni-mainz.de (Volkmar Wirth) Preprint...formulation and accuracy, Mon. Weather Rev. 120 (1992) 1675–1706. [3] D. P. Bacon , N. N. Ahmad, Z. Boybeyi, T. J. Dunn, M. S. Hall, P. C. S. Lee, R. A

  1. Adaptation of the KeratinoSens™ skin sensitisation test to animal-product-free cell culture.

    PubMed

    Belot, Nathalie; Sim, Bushra; Longmore, Christopher Longmore; Roscoe, Lottie; Treasure, Carol

    2017-03-16

    Skin sensitisation is the process by which a substance leads to an allergic reaction following skin contact. The process has been described as an adverse outcome pathway (AOP), including several key events, from skin penetration and covalent protein binding, to keratinocyte activation, dendritic cell activation and T-lymphocyte proliferation. The in vitro assay KeratinoSens™ measures the activation of keratinocytes. It is fully accepted at a regulatory level (OECD TG 442d) and appropriate for compliance with a range of legislation including the EU Cosmetics Regulation, REACH, and the CLP Regulation. Currently, many in vitro methods use animal-derived components in the cell culture systems. Many stakeholders in the cosmetics industry have both scientific and ethical concerns relating to this issue and have stated a strong preference for fully human in vitro test systems. We have adapted the KeratinoSensTM method to animal product-free conditions, and carried out an in-house validation with 21 reference substances, including those listed in the Performance Standards associated with OECD TG442d. The modified method was shown to be totally equivalent to the Validated Reference Method (VRM), with comparable values for accuracy (85.7%), sensitivity (84.6%) and specificity (87.5%), and all acceptance criteria being met. In Europe, data generated by the adapted method may be used in REACH submissions, and we are now seeking approval to list the adaptation in OECD TG 442d, enabling formal compliance with a range of global regulations.

  2. Testing Local Adaptation in a Natural Great Tit-Malaria System: An Experimental Approach

    PubMed Central

    Jenkins, Tania; Delhaye, Jessica; Christe, Philippe

    2015-01-01

    Finding out whether Plasmodium spp. are coevolving with their vertebrate hosts is of both theoretical and applied interest and can influence our understanding of the effects and dynamics of malaria infection. In this study, we tested for local adaptation as a signature of coevolution between malaria blood parasites, Plasmodium spp. and its host, the great tit, Parus major. We conducted a reciprocal transplant experiment of birds in the field, where we exposed birds from two populations to Plasmodium parasites. This experimental set-up also provided a unique opportunity to study the natural history of malaria infection in the wild and to assess the effects of primary malaria infection on juvenile birds. We present three main findings: i) there was no support for local adaptation; ii) there was a male-biased infection rate; iii) infection occurred towards the end of the summer and differed between sites. There were also site-specific effects of malaria infection on the hosts. Taken together, we present one of the few experimental studies of parasite-host local adaptation in a natural malaria system, and our results shed light on the effects of avian malaria infection in the wild. PMID:26555892

  3. Head size, weaponry, and cervical adaptation: Testing craniocervical evolutionary hypotheses in Ceratopsia.

    PubMed

    VanBuren, Collin S; Campione, Nicolás E; Evans, David C

    2015-07-01

    The anterior cervical vertebrae form the skeletal connection between the cranial and postcranial skeletons in higher tetrapods. As a result, the morphology of the atlas-axis complex is likely to be shaped by selection pressures acting on either the head or neck. The neoceratopsian (Reptilia:Dinosauria) syncervical represents one of the most highly modified atlas-axis regions in vertebrates, being formed by the complete coalescence of the three most anterior cervical vertebrae. In ceratopsids, the syncervical has been hypothesized to be an adaptation to support a massive skull, or to act as a buttress during intraspecific head-to-head combat. Here, we test these functional/adaptive hypotheses within a phylogenetic framework and critically examine the previously proposed methods for quantifying relative head size in the fossil record for the first time. Results indicate that neither the evolution of cranial weaponry nor large head size correlates with the origin of cervical fusion in ceratopsians, and we, therefore, reject both adaptive hypotheses for the origin of the syncervical. Anterior cervical fusion has evolved independently in a number of amniote clades, and further research on extant groups with this peculiar anatomy is needed to understand the evolutionary basis for cervical fusion in Neoceratopsia.

  4. Testing Local Adaptation in Five Populations of Hyalella azteca in Northern Alberta's Oil Sands Region.

    PubMed

    Beery, Steven R; Gauthier, Patrick T; Pyle, Gregory G

    2017-02-01

    Canada's oil sands hold the third largest petroleum reserves worldwide and have experienced rapid economic growth. The oil sands region provides an ideal location for studying local adaptations through reciprocal transplant (RT) because populations within the region have been historically exposed to naturally occurring bitumen. Our objectives were to (1) determine if Hyalella azteca from habitats within the oil sands region exhibited increased tolerance to constituents associated with industrial bitumen extraction compared with H. azteca from habitats outside the region; and (2) determine if any observed tolerance was attributable to local adaptation. Five populations of H. azteca were reciprocally transplanted from reclaimed and reference wetlands: four from local wetlands plus one naïve laboratory population. Survival, toxicity, and behaviour were measured before and after the RT period. Survival varied by population and site. These results show that the differences in responses among populations are likely not attributable to local adaptation and that laboratory populations of H. azteca provide ecologically relevant results when tested in the field.

  5. Removal of metal ions by Phormidium bigranulatum (cyanobacteria)-dominated mat in batch and continuous flow systems.

    PubMed

    Kumar, Dhananjay; Rai, Jyoti; Gaur, J P

    2012-01-01

    Live Phormidium bigranulatum-dominated mat successfully removed Pb(II), Cu(II) and Cd(II) from aqueous solution. Percent metal removal approached equilibrium within 4h, independent of mat thickness (0.2-1.6 mm), in batch system. But % metal removal increased with increase in mat thickness due to enhancement of biomass, which provided more metal binding sites. Metal accumulation decreased with increase in mat thickness due to lessened metal availability vis-à-vis biomass. Metal removal (%) increased with increasing mat area, but decreased with increasing metal concentration in the solution. In continuous flow system, metal accumulation increased with increasing volume of single or multi-metal solution passed over the mat. The mat removed all the tested metals from the multi-metal solution with almost the same efficiency. The maximum removal of the test metals occurred at the lowest tested flow rate. Raceway type ponds can be employed for large-scale use of Phormidium mat in bioremediation of metalliferous wastewaters.

  6. Hardware and operating features of the adaptive wall test section for the 0.3-meter transonic cryogenic tunnel

    NASA Technical Reports Server (NTRS)

    Mineck, Raymond E.

    1989-01-01

    A 13- by 13-inch adaptive wall test section was installed in the Langley 0.3-Meter Transonic Cryogenic Tunnel circuit. This test section has four solid walls and is configured for two-dimensional airfoil testing. The top and bottom walls are flexible and movable, whereas the sidwalls are rigid and fixed. The test section has a turntable to support airfoil models, a survey mechanism to probe the model wake, and provisions for a sidewall boundary-layer-control system. Details of the adaptive wall test section, the tunnel circuit modifications, the supporting instrumentation, the monitoring and control hardware, and the wall adaptation strategy are discussed. Sample results of shakedown tests with the test section empty and with an airfoil installed are also included.

  7. CR-Calculus and adaptive array theory applied to MIMO random vibration control tests

    NASA Astrophysics Data System (ADS)

    Musella, U.; Manzato, S.; Peeters, B.; Guillaume, P.

    2016-09-01

    Performing Multiple-Input Multiple-Output (MIMO) tests to reproduce the vibration environment in a user-defined number of control points of a unit under test is necessary in applications where a realistic environment replication has to be achieved. MIMO tests require vibration control strategies to calculate the required drive signal vector that gives an acceptable replication of the target. This target is a (complex) vector with magnitude and phase information at the control points for MIMO Sine Control tests while in MIMO Random Control tests, in the most general case, the target is a complete spectral density matrix. The idea behind this work is to tailor a MIMO random vibration control approach that can be generalized to other MIMO tests, e.g. MIMO Sine and MIMO Time Waveform Replication. In this work the approach is to use gradient-based procedures over the complex space, applying the so called CR-Calculus and the adaptive array theory. With this approach it is possible to better control the process performances allowing the step-by-step Jacobian Matrix update. The theoretical bases behind the work are followed by an application of the developed method to a two-exciter two-axis system and by performance comparisons with standard methods.

  8. Assessment of Postflight Locomotor Performance Utilizing a Test of Functional Mobility: Strategic and Adaptive Responses

    NASA Technical Reports Server (NTRS)

    Warren, L. E.; Mulavara, A. P.; Peters, B. T.; Cohen, H. S.; Richards, J. T.; Miller, C. A.; Brady, R.; Ruttley, T. M.; Bloomberg, J. J.

    2006-01-01

    Space flight induces adaptive modification in sensorimotor function, allowing crewmembers to operate in the unique microgravity environment. This adaptive state, however, is inappropriate for a terrestrial environment. During a re-adaptation period upon their return to Earth, crewmembers experience alterations in sensorimotor function, causing various disturbances in perception, spatial orientation, posture, gait, and eye-head coordination. Following long duration space flight, sensorimotor dysfunction would prevent or extend the time required to make an emergency egress from the vehicle; compromising crew safety and mission objectives. We are investigating two types of motor learning that may interact with each other and influence a crewmember's ability to re-adapt to Earth's gravity environment. In strategic learning, crewmembers make rapid modifications in their motor control strategy emphasizing error reduction. This type of learning may be critical during the first minutes and hours after landing. In adaptive learning, long-term plastic transformations occur, involving morphological changes and synaptic modification. In recent literature these two behavioral components have been associated with separate brain structures that control the execution of motor strategies: the strategic component was linked to the posterior parietal cortex and the adaptive component was linked to the cerebellum (Pisella, et al. 2004). The goal of this paper was to demonstrate the relative contributions of the strategic and adaptive components to the re-adaptation process in locomotor control after long duration space flight missions on the International Space Station (ISS). The Functional Mobility Test (FMT) was developed to assess crewmember s ability to ambulate postflight from an operational and functional perspective. Sixteen crewmembers were tested preflight (3 sessions) and postflight (days 1, 2, 4, 7, 25) following a long duration space flight (approx 6 months) on the ISS. We

  9. Validity and cost-effectiveness of cone adaptation test as a screening tool to detect retinitis pigmentosa

    PubMed Central

    Deshpande, Rahul; Save, Prajakta; Deshpande, Madan; Shegunashi, Mahadev; Chougule, Marium; Khandekar, Rajiv

    2016-01-01

    Background: The cone adaptation test is to detect retinitis pigmentosa (RP) cases confirmed by electroretinogram (ERG). We present the validity and cost-effectiveness of cone adaptation test as a screening tool for detecting RP. Methods: This cross-sectional study was conducted between November 2013 and December 2013. All RP cases diagnosed by ophthalmologists of H. V. Desai Eye Hospital in the last 5 years were participated in this study. The cone adaptation test was done in photopic and scotopic illumination. Failed test means 10 s or more to complete the test under scotopic illumination. A technician who was masked for cone adaptation test finding carried out ERG. Demographics, symptoms, and history of treatment were inquired. Those with flat ERG wave in scotopic condition and corresponding clinical findings were defined as having RP. Sensitivity, specificity, and false-positive and false-negative parameters of validity were estimated. The unit cost of performing test and ERG was calculated. Results: All 32 RP patients (28 male, age median 23.5 ± 14.5 years) had a vision more than 6/60 and flat wave in ERG under mesopic/scotopic illumination. Thirty-one participants failed cone adaptation test. The sensitivity was 31/32 × 100 = 97%. The specificity was 100%. There was no false-positive case. Consanguinity rate among parents was 43%. The cost of testing one child using “cone adaptation test kit” was 2.5 US $. The unit cost of diagnosing RP using ERG was 10 US $. Conclusion: Cone adaptation is a valid and cost-effective screening tool test for RP. The consanguinity rate among parents of an RP patient was high. PMID:27843226

  10. Single-Element Characterization of the LS-DYNA MAT54 Material Model

    NASA Astrophysics Data System (ADS)

    Osborne, Morgan

    Research was completed to characterize the root behavior of the LS-DYNA MAT54 composite orthotropic material model. This primarily involved investigating the constitutive relations, ply failure (damage onset), ply deletion, damage factors, and element deletion. A single shell element under uniaxial tensile and compressive loading was employed to isolate MAT54 behavior for three different idealized laminates. Simulation results were compared against expected behavior from published material properties and experimental testing. A parametric study was also conducted to confirm the behavior of all other MAT54 inputs. Overall the LS-DYNA MAT54 material model adequately predicted Unidirectional (UD), cross-ply, and fabric laminate behavior for the majority of cases. However, results showed pronounced plasticity when the strength-based Chang-Chang ply-failure criteria was reached prior to the strain-based ply-deletion parameters. This led to significant energy and failure strain errors in some cases.

  11. Biosignature Preservation Vulnerability Associated with Stress Response Metabolic Redox Mode Switching in a Mars Analogue Coupled Microbial Mat Transiting Near-Space

    NASA Astrophysics Data System (ADS)

    Archer, R.; Ralat, A.

    2016-05-01

    Examination of a coupled microbial mat recovered from Death Valley failed to detect rosickyte, both before and after exposure to near-space conditions; associated redox proxies suggest diagenesis caused by rapid adaptive microbial stress response.

  12. PROOF OF CONCEPT TEST OF A UNIQUE GASEOUS PERFLUROCARBON TRACER SYSTEM FOR VERIFICATION AND LONG TERM MONITORING OF CAPS AND COVER SYSTEMS CONDUCTED AT THE SAVANNAH RIVER SITE BENTONITE MAT TEST FACILITY.

    SciTech Connect

    HEISER,J.; SULLIVAN,T.; SERRATO,M.

    2002-02-24

    be used as a non-invasive method (if injection ports are emplaced prior to cover emplacement) on new covers or a minimally invasive method on existing covers. PFT verification will be useful at all buried waste sites using a cover system (e.g., treated or untreated chemical waste landfills) including DOE, commercial, and private sector sites. This paper discusses the initial field trial of the PFT cover monitoring system performed at the Savannah River Site (SRS) in FY01. The experiments provided a successful proof-of-principle test of the PFT technology in monitoring caps and covers. An injection and sampling array was installed in the Bentomat test cap at the SRS Caps Test Facility. This system contained 6 feet of sandy soil beneath a 1/2 inch geosynthetic clay liner covered by an HDPE liner which was covered by 2 feet of clayey top soil. PFTs were injected into the sandy soil though a pre-existing system of access pipes below the cap and soil gas samples were taken on top of the cap. Mid-way into the injection period a series of 1 1/2 inch holes were punched into the cap (through the geomembrane) to provide a positive breach in the cap. Data will be presented that shows the initial cap was fairly tight and leak free and that the artificially induced leaks were detectable within two hours of occurrence.

  13. Comparison of metabolic expenditure during CAEP versus a test adapted to aerobic capacity (Harbor test) in elderly healthy individuals.

    PubMed

    Page, E; Bonnet, J L; Durand, C

    2000-11-01

    Cardiopulmonary exercise tests are frequently used to test rate responsive pacemakers. The chronotropic assessment exercise protocol (CAEP) has been specifically proposed for the evaluation of rate responsive pacing systems. A mathematical method, based on CAEP measurements, was developed with a view of normalizing the exercise induced metabolic response. CAEP was compared to a tailored protocol (Harbor), adapted to the metabolic capacity of each patient. Harbor was set to keep the exercise duration within 10 minutes and achieve a workload as linear as possible. Metabolic parameters were continuously recorded by a cardiopulmonary system. Those data were used in the construction of slopes by the normalization method. The results of the tests performed in 16 elderly healthy patients showed no differences in metabolic or functional parameters. Slopes of the mathematical model were comparable (1.09 +/- 0.16 for CAEP vs 1.07 +/- 0.17 for Harbor), though both were higher than the value of 1, defined as normal. In both cases, linearity was confirmed by the coefficient of correlation (0.98 +/- 0.02 for CAEP and Harbor). In conclusion, no significant differences were found in the outcomes of the two protocols. Higher values of the slopes with the normalization method can be explained by the definition of the maximal predicted heart rate as 220--age, which is probably not appropriate for elderly, healthy, active subjects.

  14. Assessment in the Twenty-first Century: A Role of Computerised Adaptive Testing in National Curriculum Subjects..

    ERIC Educational Resources Information Center

    Cowan, Pamela; Morrison, Hugh

    2001-01-01

    Highlights problems associated with pen-and-paper testing, recommending a computerized adaptive testing system which measures students' abilities against the levels of the United Kingdom National Curriculum in mathematics. The current prototype of this system can be used on a school's network. Results are issued at the time of testing, and…

  15. Adapting Tests of Sign Language Assessment for Other Sign Languages--A Review of Linguistic, Cultural, and Psychometric Problems

    ERIC Educational Resources Information Center

    Haug, Tobias; Mann, Wolfgang

    2008-01-01

    Given the current lack of appropriate assessment tools for measuring deaf children's sign language skills, many test developers have used existing tests of other sign languages as templates to measure the sign language used by deaf people in their country. This article discusses factors that may influence the adaptation of assessment tests from…

  16. Psychopathology scale of the Hutt adaptation of the Bender-Gestalt Test: reliability.

    PubMed

    Miller, L J; Hutt, M L

    1975-04-01

    The test-retest reliability of the Hutt Adaptation of the Bender-Gestalt test was explored with a population of 40 process schizophrenics over a two-week interval. The total Psychopathology Scale Score was found to have high retest reliability for both male and female patients (rho = .87 for males and .83 for females). Moreover the three major components for the Scale were found to have high reliability, and fairly high reliabilities were obtained for patients scoring high as well as low on the Scale. Interjudge reliability was also found to be very high (rho = .895), confirming previous studies in this respect. On these grounds, the Scale offers promise both for clinical and research purposes.

  17. Flight control system development and flight test experience with the F-111 mission adaptive wing aircraft

    NASA Technical Reports Server (NTRS)

    Larson, R. R.

    1986-01-01

    The wing on the NASA F-111 transonic aircraft technology airplane was modified to provide flexible leading and trailing edge flaps. This wing is known as the mission adaptive wing (MAW) because aerodynamic efficiency can be maintained at all speeds. Unlike a conventional wing, the MAW has no spoilers, external flap hinges, or fairings to break the smooth contour. The leading edge flaps and three-segment trailing edge flaps are controlled by a redundant fly-by-wire control system that features a dual digital primary system architecture providing roll and symmetric commands to the MAW control surfaces. A segregated analog backup system is provided in the event of a primary system failure. This paper discusses the design, development, testing, qualification, and flight test experience of the MAW primary and backup flight control systems.

  18. Illustration of MIMIC-Model DIF Testing with the Schedule for Nonadaptive and Adaptive Personality

    PubMed Central

    Oltmanns, Thomas F.; Turkheimer, Eric

    2010-01-01

    This research provides an example of testing for differential item functioning (DIF) using multiple indicator multiple cause (MIMIC) structural equation models. True/False items on five scales of the Schedule for Nonadaptive and Adaptive Personality (SNAP) were tested for uniform DIF in a sample of Air Force recruits with groups defined by gender and ethnicity. Uniform DIF exists when an item is more easily endorsed for one group than the other, controlling for group mean differences on the variable under study. Results revealed significant DIF for many SNAP items and some effects were quite large. Differentially-functioning items can produce measurement bias and should be either deleted or modeled as if separate items were administered to different groups. Future research should aim to determine whether the DIF observed here holds for other samples. PMID:20442793

  19. Novel wound dressing based on nanofibrous PHBV-keratin mats.

    PubMed

    Yuan, Jiang; Geng, Jia; Xing, Zhicai; Shim, Kyoung-Jin; Han, Insook; Kim, Jung-Chul; Kang, Inn-Kyu; Shen, Jian

    2015-09-01

    Keratin is an important protein used for wound healing and tissue recovery. In this study, keratin was first extracted from raw materials and chemically modified to obtain stable keratin (m-keratin). The raw and m-keratin were examined by Raman spectroscopy. The molecular weight of the m-keratin was analysed by SDS-PAGE. The m-keratin was then blended with poly(hydroxybutylate-co-hydroxyvalerate) (PHBV) and electrospun to afford nanofibrous mats. These mats were characterized by field emission scanning electron microscopy (FE-SEM), electron spectroscopy for chemical analysis (ESCA) and atomic force microscopy (AFM). From the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) data, it was found that introduction of keratin enhanced cell proliferation. From wound-healing test and histological examination results, it was shown that the composite mats accelerated wound recovery remarkably as compared to the PHBV control. It was concluded that PHBV-keratin may be a good candidate as a wound dressing.

  20. Smart monitoring system based on adaptive current control for superconducting cable test

    NASA Astrophysics Data System (ADS)

    Arpaia, Pasquale; Ballarino, Amalia; Daponte, Vincenzo; Montenero, Giuseppe; Svelto, Cesare

    2014-12-01

    A smart monitoring system for superconducting cable test is proposed with an adaptive current control of a superconducting transformer secondary. The design, based on Fuzzy Gain Scheduling, allows the controller parameters to adapt continuously, and finely, to the working variations arising from transformer nonlinear dynamics. The control system is integrated in a fully digital control loop, with all the related benefits, i.e., high noise rejection, ease of implementation/modification, and so on. In particular, an accurate model of the system, controlled by a Fuzzy Gain Scheduler of the superconducting transformer, was achieved by an experimental campaign through the working domain at several current ramp rates. The model performance was characterized by simulation, under all the main operating conditions, in order to guide the controller design. Finally, the proposed monitoring system was experimentally validated at European Organization for Nuclear Research (CERN) in comparison to the state-of-the-art control system [P. Arpaia, L. Bottura, G. Montenero, and S. Le Naour, "Performance improvement of a measurement station for superconducting cable test," Rev. Sci. Instrum. 83, 095111 (2012)] of the Facility for the Research on Superconducting Cables, achieving a significant performance improvement: a reduction in the system overshoot by 50%, with a related attenuation of the corresponding dynamic residual error (both absolute and RMS) up to 52%.

  1. Development and Flight Testing of an Adaptable Vehicle Health-Monitoring Architecture

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.; Coffey, Neil C.; Gonzalez, Guillermo A.; Woodman, Keith L.; Weathered, Brenton W.; Rollins, Courtney H.; Taylor, B. Douglas; Brett, Rube R.

    2003-01-01

    Development and testing of an adaptable wireless health-monitoring architecture for a vehicle fleet is presented. It has three operational levels: one or more remote data acquisition units located throughout the vehicle; a command and control unit located within the vehicle; and a terminal collection unit to collect analysis results from all vehicles. Each level is capable of performing autonomous analysis with a trained adaptable expert system. The remote data acquisition unit has an eight channel programmable digital interface that allows the user discretion for choosing type of sensors; number of sensors, sensor sampling rate, and sampling duration for each sensor. The architecture provides framework for a tributary analysis. All measurements at the lowest operational level are reduced to provide analysis results necessary to gauge changes from established baselines. These are then collected at the next level to identify any global trends or common features from the prior level. This process is repeated until the results are reduced at the highest operational level. In the framework, only analysis results are forwarded to the next level to reduce telemetry congestion. The system's remote data acquisition hardware and non-analysis software have been flight tested on the NASA Langley B757's main landing gear.

  2. Smart monitoring system based on adaptive current control for superconducting cable test

    SciTech Connect

    Arpaia, Pasquale; Ballarino, Amalia; Montenero, Giuseppe; Daponte, Vincenzo; Svelto, Cesare

    2014-12-15

    A smart monitoring system for superconducting cable test is proposed with an adaptive current control of a superconducting transformer secondary. The design, based on Fuzzy Gain Scheduling, allows the controller parameters to adapt continuously, and finely, to the working variations arising from transformer nonlinear dynamics. The control system is integrated in a fully digital control loop, with all the related benefits, i.e., high noise rejection, ease of implementation/modification, and so on. In particular, an accurate model of the system, controlled by a Fuzzy Gain Scheduler of the superconducting transformer, was achieved by an experimental campaign through the working domain at several current ramp rates. The model performance was characterized by simulation, under all the main operating conditions, in order to guide the controller design. Finally, the proposed monitoring system was experimentally validated at European Organization for Nuclear Research (CERN) in comparison to the state-of-the-art control system [P. Arpaia, L. Bottura, G. Montenero, and S. Le Naour, “Performance improvement of a measurement station for superconducting cable test,” Rev. Sci. Instrum.83, 095111 (2012)] of the Facility for the Research on Superconducting Cables, achieving a significant performance improvement: a reduction in the system overshoot by 50%, with a related attenuation of the corresponding dynamic residual error (both absolute and RMS) up to 52%.

  3. [Motor adaptation in the Bielschowsky head-tilt test in cases of superior oblique palsy].

    PubMed

    Ohtsuki, H; Kishimoto, F; Kobashi, R; Watanabe, S; Okano, M; Furuse, H

    1992-08-01

    To elucidate a motor adaptation phenomenon in the Bielschowsky head-tilt test in cases of superior oblique palsy, a gain of the otolith-ocular reflex was studied. The amplitude of ocular counter-rolling (OCR) of the non-paretic eye was measured with a photographic method, using limbal conjunctival marks as landmarks which were marked with indigo carmine. The average preoperative OCR of the non-paretic eye was 10.49 degrees at 30 degrees of head tilt to both sides, but after corrective surgery in the paretic eye the OCR of the non-paretic eye decreased to 8.43 degrees. To clarify the relation between OCR, duration of palsy and vertical deviation of the Bielschowsky head-tilt test (BHP), which was the difference of vertical deviation measured with the head tilted to the left and right shoulders at an angle of 30 degrees, the BHP/OCR ratio was calculated. We found no relation between BHP and OCR, but the BHP/OCR ratio increased proportionally in cases of long-standing palsy, From these results an increased BHP/OCR ratio could be an adaptive phenomenon caused by secondary innervational changes or muscle contracture to minimizing the contralateral head tilt to maintain binocular single vision.

  4. Design, Fabrication, and Testing of SMA Enabled Adaptive Chevrons for Jet Noise Reduction

    NASA Technical Reports Server (NTRS)

    Turner, Travis L.; Buehrle, Ralph D.; Cano, Roberto J.; Fleming, Gary A.

    2004-01-01

    This study presents the status and results from an effort to design, fabricate, and test an adaptive jet engine chevron concept based upon embedding shape memory alloy (SMA) actuators in a composite laminate, termed a SMA hybrid composite (SMAHC). The approach for fabricating the adaptive SMAHC chevrons involves embedding prestrained Nitinol actuators on one side of the mid-plane of the composite laminate such that thermal excitation generates a thermal moment and deflects the structure. A glass-epoxy pre-preg/Nitinol ribbon material system and a vacuum hot press consolidation approach are employed. A versatile test system for control and measurement of the chevron deflection performance is described. Projection moire interferometry (PMI) is used for global deformation measurement and infrared (IR) thermography is used for 2-D temperature measurement and feedback control. A recently commercialized constitutive model for SMA and SMAHC materials is used in the finite element code ABAQUS to perform nonlinear static analysis of the chevron prototypes. Excellent agreement is achieved between the predicted and measured chevron deflection performance, thereby validating the design tool. Although the performance results presented in this paper fall short of the requirement, the concept is proven and an approach for achieving the performance objectives is evident.

  5. Testing and integrating the laser system of ARGOS: the ground layer adaptive optics for LBT

    NASA Astrophysics Data System (ADS)

    Loose, C.; Rabien, S.; Barl, L.; Borelli, J.; Deysenroth, M.; Gaessler, W.; Gemperlein, H.; Honsberg, M.; Kulas, M.; Lederer, R.; Raab, W.; Rahmer, G.; Ziegleder, J.

    2012-07-01

    The Laser Guide Star facility ARGOS will provide Ground Layer Adaptive Optics to the Large Binocular Telescope (LBT). The system operates three pulsed laser beacons above each of the two primary mirrors, which are Rayleigh scattered in 12km height. This enables correction over a wide field of view, using the adaptive secondary mirror of the LBT. The ARGOS laser system is designed around commercially available, pulsed Nd:YAG lasers working at 532 nm. In preparation for a successful commissioning, it is important to ascertain that the specifications are met for every component of the laser system. The testing of assembled, optical subsystems is likewise necessary. In particular it is required to confirm a high output power, beam quality and pulse stability of the beacons. In a second step, the integrated laser system along with its electronic cabinets are installed on a telescope simulator. This unit is capable of carrying the whole assembly and can be tilted to imitate working conditions at the LBT. It allows alignment and functionality testing of the entire system, ensuring that flexure compensation and system diagnosis work properly in different orientations.

  6. Adaptive Management Plan for Sensitive Plant Species on the Nevada Test Site

    SciTech Connect

    C. A. Wills

    2001-03-01

    The Nevada Test Site supports numerous plant species considered sensitive because of their past or present status under the Endangered Species Act and with federal and state agencies. In 1998, the U.S. Department of Energy, Nevada Operation Office (DOE/NV) prepared a Resource Management Plan which commits to protects and conserve these sensitive plant species and to minimize accumulative impacts to them. This document presents the procedures of a long-term adaptive management plan which is meant to ensure that these goals are met. It identifies the parameters that are measured for all sensitive plant populations during long-term monitoring and the adaptive management actions which may be taken if significant threats to these populations are detected. This plan does not, however, identify the current list of sensitive plant species know to occur on the Nevada Test Site. The current species list and progress on their monitoring is reported annually by DOE/NV in the Resource Management Plan.

  7. Key innovation or adaptive change? A test of leaf traits using Triodiinae in Australia.

    PubMed

    Toon, A; Crisp, M D; Gamage, H; Mant, J; Morris, D C; Schmidt, S; Cook, L G

    2015-07-28

    The evolution of novel traits ("key innovations") allows some lineages to move into new environments or adapt to changing climates, whereas other lineages may track suitable habitat or go extinct. We test whether, and how, trait shifts are linked to environmental change using Triodiinae, C4 grasses that form the dominant understory over about 30% of Australia. Using phylogenetic and relaxed molecular clock estimates, we assess the Australian biogeographic origins of Triodiinae and reconstruct the evolution of stomatal and vascular bundle positioning. Triodiinae diversified from the mid-Miocene, coincident with the aridification of Australia. Subsequent niche shifts have been mostly from the Eremaean biome to the savannah, coincident with the expansion of the latter. Biome shifts are correlated with changes in leaf anatomy and radiations within Triodiinae are largely regional. Symplectrodia and Monodia are nested within Triodia. Rather than enabling biome shifts, convergent changes in leaf anatomy have probably occurred after taxa moved into the savannah biome-they are likely to have been subsequent adaptions rather than key innovations. Our study highlights the importance of testing the timing and origin of traits assumed to be phenotypic innovations that enabled ecological shifts.

  8. Design, fabrication, and testing of SMA-enabled adaptive chevrons for jet noise reduction

    NASA Astrophysics Data System (ADS)

    Turner, Travis L.; Buehrle, Ralph D.; Cano, Roberto J.; Fleming, Gary A.

    2004-07-01

    This study presents the status and results from an effort to design, fabricate, and test an adaptive jet engine chevron concept based upon embedding shape memory alloy (SMA) actuators in a composite laminate, termed a SMA hybrid composite (SMAHC). The approach for fabricating the adaptive SMAHC chevrons involves embedding prestrained Nitinol actuators on one side of the mid-plane of the composite laminate such that thermal excitation generates a thermal moment and deflects the structure. A glass-epoxy pre-preg/Nitinol ribbon material system and a vacuum hot press consolidation approach are employed. A versatile test system for control and measurement of the chevron deflection performance is described. Projection moire interferometry (PMI) is used for global deformation measurement and infrared (IR) thermography is used for 2-D temperature measurement and feedback control. A recently commercialized constitutive model for SMA and SMAHC materials is used in the finite element code ABAQUS to perform nonlinear static analysis of the chevron prototypes. Excellent agreement is achieved between the predicted and measured chevron deflection performance, thereby validating the design tool. Although the performance results presented in this paper fall short of the requirement, the concept is proven and an approach for achieving the performance objectives is evident.

  9. Key innovation or adaptive change? A test of leaf traits using Triodiinae in Australia

    PubMed Central

    Toon, A.; Crisp, M. D.; Gamage, H.; Mant, J.; Morris, D. C.; Schmidt, S.; Cook, L. G.

    2015-01-01

    The evolution of novel traits (“key innovations”) allows some lineages to move into new environments or adapt to changing climates, whereas other lineages may track suitable habitat or go extinct. We test whether, and how, trait shifts are linked to environmental change using Triodiinae, C4 grasses that form the dominant understory over about 30% of Australia. Using phylogenetic and relaxed molecular clock estimates, we assess the Australian biogeographic origins of Triodiinae and reconstruct the evolution of stomatal and vascular bundle positioning. Triodiinae diversified from the mid-Miocene, coincident with the aridification of Australia. Subsequent niche shifts have been mostly from the Eremaean biome to the savannah, coincident with the expansion of the latter. Biome shifts are correlated with changes in leaf anatomy and radiations within Triodiinae are largely regional. Symplectrodia and Monodia are nested within Triodia. Rather than enabling biome shifts, convergent changes in leaf anatomy have probably occurred after taxa moved into the savannah biome—they are likely to have been subsequent adaptions rather than key innovations. Our study highlights the importance of testing the timing and origin of traits assumed to be phenotypic innovations that enabled ecological shifts. PMID:26215163

  10. Functional Task Test: 3. Skeletal Muscle Performance Adaptations to Space Flight

    NASA Technical Reports Server (NTRS)

    Ryder, Jeffrey W.; Wickwire, P. J.; Buxton, R. E.; Bloomberg, J. J.; Ploutz-Snyder, L.

    2011-01-01

    The functional task test is a multi-disciplinary study investigating how space-flight induced changes to physiological systems impacts functional task performance. Impairment of neuromuscular function would be expected to negatively affect functional performance of crewmembers following exposure to microgravity. This presentation reports the results for muscle performance testing in crewmembers. Functional task performance will be presented in the abstract "Functional Task Test 1: sensory motor adaptations associated with postflight alternations in astronaut functional task performance." METHODS: Muscle performance measures were obtained in crewmembers before and after short-duration space flight aboard the Space Shuttle and long-duration International Space Station (ISS) missions. The battery of muscle performance tests included leg press and bench press measures of isometric force, isotonic power and total work. Knee extension was used for the measurement of central activation and maximal isometric force. Upper and lower body force steadiness control were measured on the bench press and knee extension machine, respectively. Tests were implemented 60 and 30 days before launch, on landing day (Shuttle crew only), and 6, 10 and 30 days after landing. Seven Space Shuttle crew and four ISS crew have completed the muscle performance testing to date. RESULTS: Preliminary results for Space Shuttle crew reveal significant reductions in the leg press performance metrics of maximal isometric force, power and total work on R+0 (p<0.05). Bench press total work was also significantly impaired, although maximal isometric force and power were not significantly affected. No changes were noted for measurements of central activation or force steadiness. Results for ISS crew were not analyzed due to the current small sample size. DISCUSSION: Significant reductions in lower body muscle performance metrics were observed in returning Shuttle crew and these adaptations are likely

  11. Development and Flight Testing of an Adaptive Vehicle Health-Monitoring Architecture

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.; Coffey, Neil C.; Gonzalez, Guillermo A.; Taylor, B. Douglas; Brett, Rube R.; Woodman, Keith L.; Weathered, Brenton W.; Rollins, Courtney H.

    2002-01-01

    On going development and testing of an adaptable vehicle health-monitoring architecture is presented. The architecture is being developed for a fleet of vehicles. It has three operational levels: one or more remote data acquisition units located throughout the vehicle; a command and control unit located within the vehicle, and, a terminal collection unit to collect analysis results from all vehicles. Each level is capable of performing autonomous analysis with a trained expert system. The expert system is parameterized, which makes it adaptable to be trained to both a user's subject reasoning and existing quantitative analytic tools. Communication between all levels is done with wireless radio frequency interfaces. The remote data acquisition unit has an eight channel programmable digital interface that allows the user discretion for choosing type of sensors; number of sensors, sensor sampling rate and sampling duration for each sensor. The architecture provides framework for a tributary analysis. All measurements at the lowest operational level are reduced to provide analysis results necessary to gauge changes from established baselines. These are then collected at the next level to identify any global trends or common features from the prior level. This process is repeated until the results are reduced at the highest operational level. In the framework, only analysis results are forwarded to the next level to reduce telemetry congestion. The system's remote data acquisition hardware and non-analysis software have been flight tested on the NASA Langley B757's main landing gear. The flight tests were performed to validate the following: the wireless radio frequency communication capabilities of the system, the hardware design, command and control; software operation and, data acquisition, storage and retrieval.

  12. Managing Depression Among Homeless Mothers: Pilot Testing an Adapted Collaborative Care Intervention

    PubMed Central

    Weinreb, Linda; Upshur, Carole C.; Fletcher-Blake, Debbian; Reed, George; Frisard, Christine

    2016-01-01

    Objective Although depression is common among homeless mothers, little progress has been made in testing treatment strategies for this group. We describe pilot test results of an adapted collaborative care model for homeless mothers with depression. Method We conducted a pilot intervention study of mothers screening positive for depression in 2 randomly selected shelter-based primary care clinics in New York over 18 months in 2010–2012. Study participants completed a psychosocial, health, and mental health assessment at baseline, 3 months, and 6 months. Results One-third of women screened positive for depression (123 of 328 women). Sixty-seven women (63.2% of the eligible sample) enrolled in the intervention. At 6 months, compared to usual-care women, intervention group women were more likely to be receiving depression treatment (40.0% vs 5.9%, P = .01) and antidepressant medication (73.3% vs 5.9%, P = .001, respectively) and had more primary care physician and care manager visits at both 3 months (74.3% vs 53.3%, P = .009 and 91.4% vs 26.7%, P < .001, respectively) and 6 months (46.7% vs 23.5%, P = .003 and 70% vs 17.7%, P = .001, respectively). More women in the intervention group compared to usual-care women reported ≥ 50% improvement in depression symptoms at 6 months (30% vs 5.9%, P = .07). Conclusions This pilot study found that implementing an adapted collaborative care intervention was feasible in a shelter-based primary care clinic and had promising results that require further testing. Trial Registration ClinicalTrials.gov identifier: NCT02723058 PMID:27486545

  13. An Adaptive Association Test for Multiple Phenotypes with GWAS Summary Statistics.

    PubMed

    Kim, Junghi; Bai, Yun; Pan, Wei

    2015-12-01

    We study the problem of testing for single marker-multiple phenotype associations based on genome-wide association study (GWAS) summary statistics without access to individual-level genotype and phenotype data. For most published GWASs, because obtaining summary data is substantially easier than accessing individual-level phenotype and genotype data, while often multiple correlated traits have been collected, the problem studied here has become increasingly important. We propose a powerful adaptive test and compare its performance with some existing tests. We illustrate its applications to analyses of a meta-analyzed GWAS dataset with three blood lipid traits and another with sex-stratified anthropometric traits, and further demonstrate its potential power gain over some existing methods through realistic simulation studies. We start from the situation with only one set of (possibly meta-analyzed) genome-wide summary statistics, then extend the method to meta-analysis of multiple sets of genome-wide summary statistics, each from one GWAS. We expect the proposed test to be useful in practice as more powerful than or complementary to existing methods.

  14. Flight test results of the fuzzy logic adaptive controller-helicopter (FLAC-H)

    NASA Astrophysics Data System (ADS)

    Wade, Robert L.; Walker, Gregory W.

    1996-05-01

    The fuzzy logic adaptive controller for helicopters (FLAC-H) demonstration is a cooperative effort between the US Army Simulation, Training, and Instrumentation Command (STRICOM), the US Army Aviation and Troop Command, and the US Army Missile Command to demonstrate a low-cost drone control system for both full-scale and sub-scale helicopters. FLAC-H was demonstrated on one of STRICOM's fleet of full-scale rotary-winged target drones. FLAC-H exploits fuzzy logic in its flight control system to provide a robust solution to the control of the helicopter's dynamic, nonlinear system. Straight forward, common sense fuzzy rules governing helicopter flight are processed instead of complex mathematical models. This has resulted in a simplified solution to the complexities of helicopter flight. Incorporation of fuzzy logic reduced the cost of development and should also reduce the cost of maintenance of the system. An adaptive algorithm allows the FLAC-H to 'learn' how to fly the helicopter, enabling the control system to adjust to varying helicopter configurations. The adaptive algorithm, based on genetic algorithms, alters the fuzzy rules and their related sets to improve the performance characteristics of the system. This learning allows FLAC-H to automatically be integrated into a new airframe, reducing the development costs associated with altering a control system for a new or heavily modified aircraft. Successful flight tests of the FLAC-H on a UH-1H target drone were completed in September 1994 at the White Sands Missile Range in New Mexico. This paper discuses the objective of the system, its design, and performance.

  15. ADAPTATION OF CRACK GROWTH DETECTION TECHNIQUES TO US MATERIAL TEST REACTORS

    SciTech Connect

    A. Joseph Palmer; Sebastien P. Teysseyre; Kurt L. Davis; Gordon Kohse; Yakov Ostrovsky; David M. Carpenter; Joy L. Rempe

    2015-04-01

    A key component in evaluating the ability of Light Water Reactors to operate beyond 60 years is characterizing the degradation of materials exposed to radiation and various water chemistries. Of particular concern is the response of reactor materials to Irradiation Assisted Stress Corrosion Cracking (IASCC). Some test reactors outside the United States, such as the Halden Boiling Water Reactor (HBWR), have developed techniques to measure crack growth propagation during irradiation. The basic approach is to use a custom-designed compact loading mechanism to stress the specimen during irradiation, while the crack in the specimen is monitored in-situ using the Direct Current Potential Drop (DCPD) method. In 2012 the US Department of Energy commissioned the Idaho National Laboratory and the MIT Nuclear Reactor Laboratory (MIT NRL) to take the basic concepts developed at the HBWR and adapt them to a test rig capable of conducting in-pile IASCC tests in US Material Test Reactors. The first two and half years of the project consisted of designing and testing the loader mechanism, testing individual components of the in-pile rig and electronic support equipment, and autoclave testing of the rig design prior to insertion in the MIT Reactor. The load was applied to the specimen by means of a scissor like mechanism, actuated by a miniature metal bellows driven by pneumatic pressure and sized to fit within the small in-core irradiation volume. In addition to the loader design, technical challenges included developing robust connections to the specimen for the applied current and voltage measurements, appropriate ceramic insulating materials that can endure the LWR environment, dealing with the high electromagnetic noise environment of a reactor core at full power, and accommodating material property changes in the specimen, due primarily to fast neutron damage, which change the specimen resistance without additional crack growth. The project culminated with an in

  16. Reactive composite compositions and mat barriers

    SciTech Connect

    Langton, Christine A.; Narasimhan, Rajendran; Karraker, David G.

    2001-01-01

    A hazardous material storage area has a reactive multi-layer composite mat which lines an opening into which a reactive backfill and hazardous material are placed. A water-inhibiting cap may cover the hazardous material storage area. The reactive multi-layer composite mat has a backing onto which is placed an active layer which will neutralize or stabilize hazardous waste and a fronting layer so that the active layer is between the fronting and backing layers. The reactive backfill has a reactive agent which can stabilize or neutralize hazardous material and inhibit the movement of the hazardous material through the hazardous material storage area.

  17. Nitrogen cycle in microbial mats: completely unknown?

    NASA Astrophysics Data System (ADS)

    Coban, O.; Bebout, B.

    2015-12-01

    Microbial mats are thought to have originated around 3.7 billion years ago, most likely in the areas around submarine hydrothermal vents, which supplied a source of energy in the form of reduced chemical species from the Earth's interior. Active hydrothermal vents are also believed to exist on Jupiter's moon Europa, Saturn's moon Enceladus, and on Mars, earlier in that planet's history. Microbial mats have been an important force in the maintenance of Earth's ecosystems and the first photosynthesis was also originated there. Microbial mats are believed to exhibit most, if not all, biogeochemical processes that exist in aquatic ecosystems, due to the presence of different physiological groups of microorganisms therein. While most microbially mediated biogeochemical transformations have been shown to occur within microbial mats, the nitrogen cycle in the microbial mats has received very little study in spite of the fact that nitrogen usually limits growth in marine environments. We will present the first results in the determination of a complete nitrogen budget for a photosynthetic microbial mat. Both in situ sources and sinks of nitrogen in photosynthetic microbial mats are being measured using stable isotope techniques. Our work has a particular focus on recently described, but poorly understood, processes, e.g., anammox and dissimilatory nitrate reduction, and an emphasis on understanding the role that nitrogen cycling may play in generating biogenic nitrogen isotopic signatures and biomarker molecules. Measurements of environmental controls on nitrogen cycling should offer insight into the nature of co-evolution of these microbial communities and their planets of origin. Identifying the spatial (microscale) as well as temporal (diel and seasonal) distribution of nitrogen transformations, e.g., rates of nitrification and denitrification, within mats, particularly with respect to the distribution of photosynthetically-produced oxygen, is anticipated. The results

  18. Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

    PubMed Central

    Hess, Allison E.; Potter, Kelsey A.; Tyler, Dustin J.; Zorman, Christian A.; Capadona, Jeffrey R.

    2013-01-01

    Implantable microdevices are gaining significant attention for several biomedical applications1-4. Such devices have been made from a range of materials, each offering its own advantages and shortcomings5,6. Most prominently, due to the microscale device dimensions, a high modulus is required to facilitate implantation into living tissue. Conversely, the stiffness of the device should match the surrounding tissue to minimize induced local strain7-9. Therefore, we recently developed a new class of bio-inspired materials to meet these requirements by responding to environmental stimuli with a change in mechanical properties10-14. Specifically, our poly(vinyl acetate)-based nanocomposite (PVAc-NC) displays a reduction in stiffness when exposed to water and elevated temperatures (e.g. body temperature). Unfortunately, few methods exist to quantify the stiffness of materials in vivo15, and mechanical testing outside of the physiological environment often requires large samples inappropriate for implantation. Further, stimuli-responsive materials may quickly recover their initial stiffness after explantation. Therefore, we have developed a method by which the mechanical properties of implanted microsamples can be measured ex vivo, with simulated physiological conditions maintained using moisture and temperature control13,16,17. To this end, a custom microtensile tester was designed to accommodate microscale samples13,17 with widely-varying Young's moduli (range of 10 MPa to 5 GPa). As our interests are in the application of PVAc-NC as a biologically-adaptable neural probe substrate, a tool capable of mechanical characterization of samples at the microscale was necessary. This tool was adapted to provide humidity and temperature control, which minimized sample drying and cooling17. As a result, the mechanical characteristics of the explanted sample closely reflect those of the sample just prior to explantation. The overall goal of this method is to quantitatively assess

  19. Ecological succession leads to chemosynthesis in mats colonizing wood in sea water.

    PubMed

    Kalenitchenko, Dimitri; Dupraz, Marlène; Le Bris, Nadine; Petetin, Carole; Rose, Christophe; West, Nyree J; Galand, Pierre E

    2016-09-01

    Chemosynthetic mats involved in cycling sulfur compounds are often found in hydrothermal vents, cold seeps and whale falls. However, there are only few records of wood fall mats, even though the presence of hydrogen sulfide at the wood surface should create a perfect niche for sulfide-oxidizing bacteria. Here we report the growth of microbial mats on wood incubated under conditions that simulate the Mediterranean deep-sea temperature and darkness. We used amplicon and metagenomic sequencing combined with fluorescence in situ hybridization to test whether a microbial succession occurs during mat formation and whether the wood fall mats present chemosynthetic features. We show that the wood surface was first colonized by sulfide-oxidizing bacteria belonging to the Arcobacter genus after only 30 days of immersion. Subsequently, the number of sulfate reducers increased and the dominant Arcobacter phylotype changed. The ecological succession was reflected by a change in the metabolic potential of the community from chemolithoheterotrophs to potential chemolithoautotrophs. Our work provides clear evidence for the chemosynthetic nature of wood fall ecosystems and demonstrates the utility to develop experimental incubation in the laboratory to study deep-sea chemosynthetic mats.

  20. Testing Adaptive Hypotheses of Convergence with Functional Landscapes: A Case Study of Bone-Cracking Hypercarnivores

    PubMed Central

    Tseng, Zhijie Jack

    2013-01-01

    Morphological convergence is a well documented phenomenon in mammals, and adaptive explanations are commonly employed to infer similar functions for convergent characteristics. I present a study that adopts aspects of theoretical morphology and engineering optimization to test hypotheses about adaptive convergent evolution. Bone-cracking ecomorphologies in Carnivora were used as a case study. Previous research has shown that skull deepening and widening are major evolutionary patterns in convergent bone-cracking canids and hyaenids. A simple two-dimensional design space, with skull width-to-length and depth-to-length ratios as variables, was used to examine optimized shapes for two functional properties: mechanical advantage (MA) and strain energy (SE). Functionality of theoretical skull shapes was studied using finite element analysis (FEA) and visualized as functional landscapes. The distribution of actual skull shapes in the landscape showed a convergent trend of plesiomorphically low-MA and moderate-SE skulls evolving towards higher-MA and moderate-SE skulls; this is corroborated by FEA of 13 actual specimens. Nevertheless, regions exist in the landscape where high-MA and lower-SE shapes are not represented by existing species; their vacancy is observed even at higher taxonomic levels. Results highlight the interaction of biomechanical and non-biomechanical factors in constraining general skull dimensions to localized functional optima through evolution. PMID:23734244

  1. Flight Test Comparison of Different Adaptive Augmentations for Fault Tolerant Control Laws for a Modified F-15 Aircraft

    NASA Technical Reports Server (NTRS)

    Burken, John J.; Hanson, Curtis E.; Lee, James A.; Kaneshige, John T.

    2009-01-01

    This report describes the improvements and enhancements to a neural network based approach for directly adapting to aerodynamic changes resulting from damage or failures. This research is a follow-on effort to flight tests performed on the NASA F-15 aircraft as part of the Intelligent Flight Control System research effort. Previous flight test results demonstrated the potential for performance improvement under destabilizing damage conditions. Little or no improvement was provided under simulated control surface failures, however, and the adaptive system was prone to pilot-induced oscillations. An improved controller was designed to reduce the occurrence of pilot-induced oscillations and increase robustness to failures in general. This report presents an analysis of the neural networks used in the previous flight test, the improved adaptive controller, and the baseline case with no adaptation. Flight test results demonstrate significant improvement in performance by using the new adaptive controller compared with the previous adaptive system and the baseline system for control surface failures.

  2. Organization and Evolutionary Trajectory of the Mating Type (MAT) Locus in Dermatophyte and Dimorphic Fungal Pathogens▿ †

    PubMed Central

    Li, Wenjun; Metin, Banu; White, Theodore C.; Heitman, Joseph

    2010-01-01

    Sexual reproduction in fungi is governed by a specialized genomic region, the mating type (MAT) locus, whose gene identity, organization, and complexity are diverse. We identified the MAT locus of five dermatophyte fungal pathogens (Microsporum gypseum, Microsporum canis, Trichophyton equinum, Trichophyton rubrum, and Trichophyton tonsurans) and a dimorphic fungus, Paracoccidioides brasiliensis, and performed phylogenetic analyses. The identified MAT locus idiomorphs of M. gypseum control cell type identity in mating assays, and recombinant progeny were produced. Virulence tests in Galleria mellonella larvae suggest the two mating types of M. gypseum may have equivalent virulence. Synteny analysis revealed common features of the MAT locus shared among these five dermatophytes: namely, a small size (∼3 kb) and a novel gene arrangement. The SLA2, COX13, and APN2 genes, which flank the MAT locus in other Ascomycota are instead linked on one side of the dermatophyte MAT locus. In addition, the transcriptional orientations of the APN2 and COX13 genes are reversed compared to the dimorphic fungi Histoplasma capsulatum, Coccidioides immitis, and Coccidioides posadasii. A putative transposable element, pogo, was found to have inserted in the MAT1-2 idiomorph of one P. brasiliensis strain but not others. In conclusion, the evolution of the MAT locus of the dermatophytes and dimorphic fungi from the last common ancestor has been punctuated by both gene acquisition and expansion, and asymmetric gene loss. These studies further support a foundation to develop molecular and genetic tools for dermatophyte and dimorphic human fungal pathogens. PMID:19880755

  3. L1 Adaptive Control Law for Flexible Space Launch Vehicle and Proposed Plan for Flight Test Validation

    NASA Technical Reports Server (NTRS)

    Kharisov, Evgeny; Gregory, Irene M.; Cao, Chengyu; Hovakimyan, Naira

    2008-01-01

    This paper explores application of the L1 adaptive control architecture to a generic flexible Crew Launch Vehicle (CLV). Adaptive control has the potential to improve performance and enhance safety of space vehicles that often operate in very unforgiving and occasionally highly uncertain environments. NASA s development of the next generation space launch vehicles presents an opportunity for adaptive control to contribute to improved performance of this statically unstable vehicle with low damping and low bending frequency flexible dynamics. In this paper, we consider the L1 adaptive output feedback controller to control the low frequency structural modes and propose steps to validate the adaptive controller performance utilizing one of the experimental test flights for the CLV Ares-I Program.

  4. Usability Testing and Adaptation of the Pediatric Cardiovascular Risk Reduction Clinical Decision Support Tool

    PubMed Central

    Furberg, Robert D; Bagwell, Jacqueline E; LaBresh, Kenneth A

    2016-01-01

    Background Cardiovascular disease (CVD) is 1 of the leading causes of death, years of life lost, and disability-adjusted years of life lost worldwide. CVD prevention for children and teens is needed, as CVD risk factors and behaviors beginning in youth contribute to CVD development. In 2012, the National Heart, Lung, and Blood Institute released their “Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents” for clinicians, describing CVD risk factors they should address with patients at primary care preventative visits. However, uptake of new guidelines is slow. Clinical decision support (CDS) tools can improve guideline uptake. In this paper, we describe our process of testing and adapting a CDS tool to help clinicians evaluate patient risk, recommend behaviors to prevent development of risk, and complete complex calculations to determine appropriate interventions as recommended by the guidelines, using a user-centered design approach. Objective The objective of the study was to assess the usability of a pediatric CVD risk factor tool by clinicians. Methods The tool was tested using one-on-one in-person testing and a “think aloud” approach with 5 clinicians and by using the tool in clinical practice along with formal usability metrics with 14 pediatricians. Thematic analysis of the data from the in-person testing and clinical practice testing identified suggestions for change in 3 major areas: user experience, content refinement, and technical deployment. Descriptive statistical techniques were employed to summarize users’ overall experience with the tool. Results Data from testers showed that general reactions toward the CDS tool were positive. Clinical practice testers suggested revisions to make the application more user-friendly, especially for clinicians using the application on the iPhone, and called for refining recommendations to be more succinct and better tailored to the patient. Tester feedback was

  5. Validation of a microsatellite panel for parentage testing of locally adapted and commercial goats in Brazil.

    PubMed

    da Silva, Elizabete Cristina; McManus, Concepta Margaret; de Paiva Guimarães, Maria Pia Souza Lima Mattos; Gouveia, Aurora M G; Facó, Olivardo; Pimentel, Daniel M; Caetano, Alexandre Rodrigues; Paiva, Samuel Rezende

    2014-03-01

    Brazilian goats are generally kept in small herds and extensive rearing systems, mainly in the northeastern region of the country. Despite production improvement in recent years, the lack of pedigree control has affected genetic progress. This study aimed to validate a panel of 16 microsatellites for parentage testing in locally adapted and commercial goats breeds raised in Brazil, as well as to compare its efficiency with the panel recommended by the Brazilian Ministry of Agriculture, Livestock and Supplies (MAPA) in 2004. The number of alleles and expected heterozygosity (He) per marker ranged from four to 18, and from 0.051 to 0.831, respectively. Using all markers, 100% of parentage cases of the validation dataset were resolved with a strict confidence level of 95%. The 16 microsatellites panel showed adequate exclusion power (99.99%) and identity accuracy (99.99%). Suggestions for improvement of the marker panel endorsed by MAPA are provided.

  6. Validation of a microsatellite panel for parentage testing of locally adapted and commercial goats in Brazil

    PubMed Central

    da Silva, Elizabete Cristina; McManus, Concepta Margaret; de Paiva Guimarães, Maria Pia Souza Lima Mattos; Gouveia, Aurora M.G.; Facó, Olivardo; Pimentel, Daniel M.; Caetano, Alexandre Rodrigues; Paiva, Samuel Rezende

    2014-01-01

    Brazilian goats are generally kept in small herds and extensive rearing systems, mainly in the northeastern region of the country. Despite production improvement in recent years, the lack of pedigree control has affected genetic progress. This study aimed to validate a panel of 16 microsatellites for parentage testing in locally adapted and commercial goats breeds raised in Brazil, as well as to compare its efficiency with the panel recommended by the Brazilian Ministry of Agriculture, Livestock and Supplies (MAPA) in 2004. The number of alleles and expected heterozygosity (He) per marker ranged from four to 18, and from 0.051 to 0.831, respectively. Using all markers, 100% of parentage cases of the validation dataset were resolved with a strict confidence level of 95%. The 16 microsatellites panel showed adequate exclusion power (99.99%) and identity accuracy (99.99%). Suggestions for improvement of the marker panel endorsed by MAPA are provided. PMID:24688291

  7. Adaptive support for aircraft panel testing: New method and its experimental verification on a beam structure

    NASA Astrophysics Data System (ADS)

    Sachau, Delf; Baschke, Manuel

    2017-04-01

    Acoustic transmissibility of aircraft panels is measured in full-scale test rigs. The panels are supported at their frames. These boundary conditions do not take into account the dynamic influence of the fuselage, which is significant in the frequency range below 300 Hz. This paper introduces a new adaptive boundary system (ABS). It combines accelerometers and electrodynamic shakers with real-time signal processing. The ABS considers the dynamic effect of the fuselage on the panel. The frames are dominating the dynamic behaviour of a fuselage in the low-frequency range. Therefore, the new method is applied to a beam representing a frame of the aircraft structure. The experimental results are evaluated and the precision of the ABS is discussed. The theoretical apparent mass representing the cut-off part of a frame is calculated and compared with the apparent mass, as provided by the ABS. It is explained how the experimental set-up limits the precision of the ABS.

  8. The focal plane adaptive optics test box of the Observatoire du Mont-Mégantic

    NASA Astrophysics Data System (ADS)

    Deschênes, William; Brousseau, Denis; Lavigne, Jean-Francois; Thibault, Simon; Véran, Jean-Pierre

    2014-08-01

    With the upcoming construction of Extremely Large Telescopes, several existing technologies are being pushed beyond their performance limit and it becomes essential to develop and evaluate new alternatives. The "Observatoire du Mont Mégantic" (OMM) hosts a telescope having a 1.6-meter diameter primary. The OMM telescope is known to be an excellent location to develop and test precursor instruments which are then upscaled to larger telescopes (ex. SPIOMM which led to SITELLE at the CFHT). We present a specifically designed focal plane box for the OMM which will allow to evaluate, directly on-sky, the performance of a number of next generation adaptive optics related technologies The system will able us to compare the performance of several new wavefront sensors in contrast with the current standard, the Shack-Hartman wavefront sensor.

  9. Conceptualising computerized adaptive testing for measurement of latent variables associated with physical objects

    NASA Astrophysics Data System (ADS)

    Camargo, F. R.; Henson, B.

    2015-02-01

    The notion of that more or less of a physical feature affects in different degrees the users' impression with regard to an underlying attribute of a product has frequently been applied in affective engineering. However, those attributes exist only as a premise that cannot directly be measured and, therefore, inferences based on their assessment are error-prone. To establish and improve measurement of latent attributes it is presented in this paper the concept of a stochastic framework using the Rasch model for a wide range of independent variables referred to as an item bank. Based on an item bank, computerized adaptive testing (CAT) can be developed. A CAT system can converge into a sequence of items bracketing to convey information at a user's particular endorsement level. It is through item banking and CAT that the financial benefits of using the Rasch model in affective engineering can be realised.

  10. Lipid biomarkers, pigments and cyanobacterial diversity of microbial mats across intertidal flats of the arid coast of the Arabian Gulf (Abu Dhabi, UAE).

    PubMed

    Abed, Raeid M M; Kohls, Katharina; Schoon, Raphaela; Scherf, Ann-Kathrin; Schacht, Marion; Palinska, Katarzyna A; Al-Hassani, Huda; Hamza, Waleed; Rullkötter, Jürgen; Golubic, Stjepko

    2008-09-01

    Variations in morphology, fatty acids, pigments and cyanobacterial community composition were studied in microbial mats across intertidal flats of the arid Arabian Gulf coast. These mats experience combined extreme conditions of salinity, temperature, UV radiation and desiccation depending on their tidal position. Different mat forms were observed depending on the topology of the coast and location. The mats contained 63 fatty acids in different proportions. The increased amounts of unsaturated fatty acids (12-39%) and the trans/cis ratio (0.6-1.6%) of the cyanobacterial fatty acid n-18:1omega9 in the higher tidal mats suggested an adaptation of the mat microorganisms to environmental stress. Chlorophyll a concentrations suggested lower cyanobacterial abundance in the higher than in the lower intertidal mats. Scytonemin concentrations were dependent on the increase in solar irradiation, salinity and desiccation. The mats showed richness in cyanobacterial species, with Microcoleus chthonoplastes and Lyngbya aestuarii morphotypes as the dominant cyanobacteria. Denaturing gradient gel electrophoresis patterns suggested shifts in the cyanobacterial community dependent on drainage efficiency and salinity from lower to higher tidal zones. We conclude that the topology of the coast and the variable extreme environmental conditions across the tidal flat determine the distribution of microbial mats as well as the presence or absence of different microorganisms.

  11. Adaptability test of lettuce to soil-like substrate in bioregenerative life support system

    NASA Astrophysics Data System (ADS)

    Min, Yan; Liu, Professor Hong; Wenting, Fu

    Plant cultivation using soil-like substrate (SLS) is considered to be a feasible option for building up matter for biological turnover in bioregenerative life support system (BLSS) by many researchers. The characteristics of SLS are different from those of true soil therefore it is very important to study the adaptability of candidate crop to SLS in BLSS. This study was carried out in three successive steps to test the adaptability of lettuce (Lactuca sativa L.) to rice straw SLS in BLSS of China. First, six Chinese specific lettuce cultivars which were selected for Chinese advanced life support system were planted into the same rice straw SLS, which was to determine the more suitable plant cultivar to do the next experiment. The results showed that Sharp Leaf lettuce and Red lettuce were more suitable for SLS than other cultivars. Second, the possibility of increasing the crop yield on the SLS was conducted by changing the soil depth and plant density. Sharp Leaf lettuce and Red lettuce were used into this experiment in order to obtain the highest yield under the smallest soil volume and weight at the same light intensity. Crop edible biomass, crop nutrition content and photosynthetic characteristics were estimated during the experiment. Red lettuce obtained higher biomass and photosynthesis capacity. Lastly, the stability of planting system of lettuce and SLS was evaluated in the closed controlled system. Red lettuce would be the test plant. In this experiment different age lettuce groups would be planted together and gas exchange would be measured. In all of these experiments soil physical and chemical characteristics were also be measured which will be the basal data for further research.

  12. Niche evolution and adaptive radiation: Testing the order of trait divergence

    USGS Publications Warehouse

    Ackerly, D.D.; Schwilk, D.W.; Webb, C.O.

    2006-01-01

    In the course of an adaptive radiation, the evolution of niche parameters is of particular interest for understanding modes of speciation and the consequences for coexistence of related species within communities. We pose a general question: In the course of an evolutionary radiation, do traits related to within-community niche differences (?? niche) evolve before or after differentiation of macrohabitat affinity or climatic tolerances (?? niche)? Here we introduce a new test to address this question, based on a modification of the method of independent contrasts. The divergence order test (DOT) is based on the average age of the nodes on a tree, weighted by the absolute magnitude of the contrast at each node for a particular trait. The comparison of these weighted averages reveals whether large divergences for one trait have occurred earlier or later in the course of diversification, relative to a second trait; significance is determined by bootstrapping from maximum-likelihood ancestral state reconstructions. The method is applied to the evolution of Ceanothus, a woody plant group in California, in which co-occurring species exhibit significant differences in a key leaf trait (specific leaf area) associated with contrasting physiological and life history strategies. Co-occurring species differ more for this trait than expected under a null model of community assembly. This ?? niche difference evolved early in the divergence of two major subclades within Ceanothus, whereas climatic distributions (?? niche traits) diversified later within each of the subclades. However, rapid evolution of climate parameters makes inferences of early divergence events highly uncertain, and differentiation of the ?? niche might have taken place throughout the evolution of the group, without leaving a clear phylogenetic signal. Similar patterns observed in several plant and animal groups suggest that early divergence of ?? niche traits might be a common feature of niche evolution in

  13. Adaptive elastic-net sparse principal component analysis for pathway association testing.

    PubMed

    Chen, Xi

    2011-10-24

    Pathway or gene set analysis has become an increasingly popular approach for analyzing high-throughput biological experiments such as microarray gene expression studies. The purpose of pathway analysis is to identify differentially expressed pathways associated with outcomes. Important challenges in pathway analysis are selecting a subset of genes contributing most to association with clinical phenotypes and conducting statistical tests of association for the pathways efficiently. We propose a two-stage analysis strategy: (1) extract latent variables representing activities within each pathway using a dimension reduction approach based on adaptive elastic-net sparse principal component analysis; (2) integrate the latent variables with the regression modeling framework to analyze studies with different types of outcomes such as binary, continuous or survival outcomes. Our proposed approach is computationally efficient. For each pathway, because the latent variables are estimated in an unsupervised fashion without using disease outcome information, in the sample label permutation testing procedure, the latent variables only need to be calculated once rather than for each permutation resample. Using both simulated and real datasets, we show our approach performed favorably when compared with five other currently available pathway testing methods.

  14. Adaptive Elastic-Net Sparse Principal Component Analysis for Pathway Association Testing

    PubMed Central

    Chen, Xi

    2011-01-01

    Pathway or gene set analysis has become an increasingly popular approach for analyzing high-throughput biological experiments such as microarray gene expression studies. The purpose of pathway analysis is to identify differentially expressed pathways associated with outcomes. Important challenges in pathway analysis are selecting a subset of genes contributing most to association with clinical phenotypes and conducting statistical tests of association for the pathways efficiently. We propose a two-stage analysis strategy: (1) extract latent variables representing activities within each pathway using a dimension reduction approach based on adaptive elastic-net sparse principal component analysis; (2) integrate the latent variables with the regression modeling framework to analyze studies with different types of outcomes such as binary, continuous or survival outcomes. Our proposed approach is computationally efficient. For each pathway, because the latent variables are estimated in an unsupervised fashion without using disease outcome information, in the sample label permutation testing procedure, the latent variables only need to be calculated once rather than for each permutation resample. Using both simulated and real datasets, we show our approach performed favorably when compared with five other currently available pathway testing methods. PMID:23089825

  15. Adaptive combination of P-values for family-based association testing with sequence data.

    PubMed

    Lin, Wan-Yu

    2014-01-01

    Family-based study design will play a key role in identifying rare causal variants, because rare causal variants can be enriched in families with multiple affected subjects. Furthermore, different from population-based studies, family studies are robust to bias induced by population substructure. It is well known that rare causal variants are difficult to detect from single-locus tests. Therefore, burden tests and non-burden tests have been developed, by combining signals of multiple variants in a chromosomal region or a functional unit. This inevitably incorporates some neutral variants into the test statistics, which can dilute the power of statistical methods. To guard against the noise caused by neutral variants, we here propose an 'adaptive combination of P-values method' (abbreviated as 'ADA'). This method combines per-site P-values of variants that are more likely to be causal. Variants with large P-values (which are more likely to be neutral variants) are discarded from the combined statistic. In addition to performing extensive simulation studies, we applied these tests to the Genetic Analysis Workshop 17 data sets, where real sequence data were generated according to the 1000 Genomes Project. Compared with some existing methods, ADA is more robust to the inclusion of neutral variants. This is a merit especially when dichotomous traits are analyzed. However, there are some limitations for ADA. First, it is more computationally intensive. Second, pedigree structures and founders' sequence data are required for the permutation procedure. Third, unrelated controls cannot be included. We here show that, for family-based studies, the application of ADA is limited to dichotomous trait analyses with full pedigree information.

  16. Executive Functioning in Three Groups of Pupils in D-KEFSs: Selected Issues in Adapting the Test Battery for Slovakia

    ERIC Educational Resources Information Center

    Ferjencík, Ján; Slavkovská, Miriam; Kresila, Juraj

    2015-01-01

    The paper reports on the adaptation of a D-KEFS test battery for Slovakia. Drawing on concrete examples, it describes and illustrates the key issues relating to the transfer of test items from one socio-cultural environment to another. The standardisation sample of the population of Slovak pupils in the fourth year of primary school included 250…

  17. A Comparison of an Expert Systems Approach to Computerized Adaptive Testing and an Item Response Theory Model.

    ERIC Educational Resources Information Center

    Frick, Theodore W.

    Expert systems can be used to aid decisionmaking. A computerized adaptive test is one kind of expert system, although not commonly recognized as such. A new approach, termed EXSPRT, was devised that combines expert systems reasoning and sequential probability ratio test stopping rules. Two versions of EXSPRT were developed, one with random…

  18. An Empirical Comparison of an Expert Systems Approach and an IRT Approach to Computer-Based Adaptive Mastery Testing.

    ERIC Educational Resources Information Center

    Luk, HingKwan

    This study examined whether an expert system approach involving intelligent selection of items (EXSPRT-I) is as efficient as item response theory (IRT) based three-parameter adaptive mastery testing (AMT) when there are enough subjects to estimate the three IRT item parameters for all items in the test and when subjects in the item parameter…

  19. An Empirical Bayes Enhancement of Mantel-Haenszel DIF Analysis for Computer-Adaptive Tests. LSAC Research Report Series.

    ERIC Educational Resources Information Center

    Zwick, Rebecca; Thayer, Dorothy T.

    This study investigated the applicability to computerized adaptive testing (CAT) data of a differential item functioning (DIF) analysis that involves an empirical Bayes (EB) enhancement of the popular Mantel Haenszel (MH) DIF analysis method. The computerized Law School Admission Test (LSAT) assumed for this study was similar to that currently…

  20. HazMatID (trademark) Replacement Project

    DTIC Science & Technology

    2013-05-09

    uses FTIR spectroscopy. It has the capability to identify chemical warfare agents, explosives , toxic industrial chemicals, narcotics, and...off-the-shelf, Fourier transform infrared spectroscopy ( FTIR ) instruments 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18...replacement for the Smiths Detection HazMatIDTM on the 886H allowance standard, a search of Fourier transform infrared spectroscopy ( FTIR ) instruments was

  1. Tensile and compressive behavior of a swirl mat composite

    SciTech Connect

    Ruggles, M.B.

    1998-07-01

    The Durability of Lightweight Composite Structures Project was established at Oak Ridge National Laboratory (ORNL) by the US Department of Energy to provide the experimentally-based, durability-driven design guidelines necessary to assure long-term structural integrity of automotive composite components. The initial focus of the ORNL Durability Project was on one representative reference material--an isocyanurate (polyurethane) reinforced with continuous strand, swirl-mat E-glass. The present report describes tensile and compressive testing and results for the reference composite. Behavior trends and proportional limit are established for both tension and compression. Damage development due to tensile loading and strain rate effects are discussed.

  2. Adaptation of a Turbine Test Facility to High-Temperature Research (Adaptation d’un banc de Turbine aux Recherches pour les Hautes Temperatures,

    DTIC Science & Technology

    1980-12-19

    Des hautes temperatures devant turbine sur turborgacteur et turbines A gaz. (High turbine inlet temperatures in turbo - jet engines and gas turbines ... turbo - jet engines .) Revue Gn(rale de Thermique, No. 166, October 1975 15 D. Arnal Etude exprimentale et thgorique de la transition de la couche J.C...r AD-AIOl 374 ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUBH (ENGLAND) F/B 10/1 ADAPTATION OF A TURBINE TEST FACILITY TO HIGH-TEMPERATURE RESEA--ETC(U) DEC

  3. Growth and metal removal potential of a Phormidium bigranulatum-dominated mat following long-term exposure to elevated levels of copper.

    PubMed

    Kumar, Dhananjay; Gaur, J P

    2014-09-01

    The present study explores the tolerance and metal removal response of a well-developed 2-week-old Phormidium mat after long-term exposure to Cu(2+)-enriched medium. Cu(2+) enrichment inhibited increase in mat biomass in a concentration-dependent manner. Mat area and the number of entrapped air bubbles decreased as Cu(2+) concentration increased in the medium. Decrease in number of air bubbles obviously reflects the adverse effect of Cu(2+) on photosynthetic performance of the mat. Metal enrichment did not substantially alter the amount of pigments, such as chlorophyll a, chlorophyll b, carotenoids, and phycocyanin, in the mat. Enhancement of Cu(2+) concentration in the medium led to changes in species composition of the test mat; however, Phormidium bigranulatum always remained the dominant organism. Relative share of green algae and some cyanobacterial taxa, namely, Lyngbya sp. and Oscillatoria tenuis, in the mat were increased by Cu(2+) enrichment. The mat successfully removed 80 to 94 % Cu(2+) from the growth medium containing 10 to 100 μM Cu(2+). Extracellular polysaccharides, whose share increased in the mat community after metal addition, seem to have contributed substantially to metal binding by the mat biomass.

  4. Sperm competition leads to functional adaptations in avian testes to maximize sperm quantity and quality.

    PubMed

    Lüpold, Stefan; Wistuba, Joachim; Damm, Oliver S; Rivers, James W; Birkhead, Tim R

    2011-05-01

    The outcome of sperm competition (i.e. competition for fertilization between ejaculates from different males) is primarily determined by the relative number and quality of rival sperm. Therefore, the testes are under strong selection to maximize both sperm number and quality, which are likely to result in trade-offs in the process of spermatogenesis (e.g. between the rate of spermatogenesis and sperm length or sperm energetics). Comparative studies have shown positive associations between the level of sperm competition and both relative testis size and the proportion of seminiferous (sperm-producing) tissue within the testes. However, it is unknown how the seminiferous tissue itself or the process of spermatogenesis might evolve in response to sperm competition. Therefore, we quantified the different germ cell types and Sertoli cells (SC) in testes to assess the efficiency of sperm production and its associations with sperm length and mating system across 10 species of New World Blackbirds (Icteridae) that show marked variation in sperm length and sperm competition level. We found that species under strong sperm competition generate more round spermatids (RS)/spermatogonium and have SC that support a greater number of germ cells, both of which are likely to increase the maximum sperm output. However, fewer of the RS appeared to elongate to mature spermatozoa in these species, which might be the result of selection for discarding spermatids with undesirable characteristics as they develop. Our results suggest that, in addition to overall size and gross morphology, testes have also evolved functional adaptations to maximize sperm quantity and quality.

  5. Arcjet Testing of Woven Carbon Cloth for Use on Adaptive Deployable Entry Placement Technology

    NASA Technical Reports Server (NTRS)

    Arnold, James O.; laub, Bernard; Chen, Yih-Kang; Prabhu, Dinesh K.; Bittner, M. E.; Venkatapathy, Ethiraj

    2013-01-01

    This paper describes arcjet testing and analysis that has successfully demonstrated the viability of three dimensional woven carbon cloth for dual use in the Adaptive Deployable Entry Placement Technology (ADEPT). ADEPT is an umbrella-like entry system that is folded for stowage in the launch vehicle s shroud and deployed in space prior to reaching the atmospheric interface. A key feature of the ADEPT concept is its lower ballistic coefficient for delivery of a given payload than those for conventional, rigid body entry systems. The benefits that accrue from the lower ballistic coefficient include factor of ten reductions of deceleration forces and entry heating. The former enables consideration of new classes of scientific instruments for solar system exploration while the latter enables the design of a more efficient thermal protection system. The carbon cloth now base lined for ADEPT has a dual use in that it serves as ADEPT s thermal protection system and as the "skin" that transfers aerodynamic deceleration loads to its umbrella-like substructure. The arcjet testing described in this paper was conducted for some of the higher heating conditions for a future Venus mission using the ADEPT concept, thereby showing that the carbon cloth can perform in a relevant entry environment. The ADEPT project considered the carbon cloth to be mission enabling and was carrying it as a major risk during Fiscal Year 2012. The testing and analysis reported here played a major role in retiring that risk and is highly significant to the success and possible adoption of ADEPT for future NASA missions. Finally, this paper also describes a preliminary engineering level code, based on the arcjet data, that can be used to estimate cloth thickness for future missions using ADEPT and to predict carbon cloth performance in future arcjet tests.

  6. Intelligent Condition Diagnosis Method Based on Adaptive Statistic Test Filter and Diagnostic Bayesian Network

    PubMed Central

    Li, Ke; Zhang, Qiuju; Wang, Kun; Chen, Peng; Wang, Huaqing

    2016-01-01

    A new fault diagnosis method for rotating machinery based on adaptive statistic test filter (ASTF) and Diagnostic Bayesian Network (DBN) is presented in this paper. ASTF is proposed to obtain weak fault features under background noise, ASTF is based on statistic hypothesis testing in the frequency domain to evaluate similarity between reference signal (noise signal) and original signal, and remove the component of high similarity. The optimal level of significance α is obtained using particle swarm optimization (PSO). To evaluate the performance of the ASTF, evaluation factor Ipq is also defined. In addition, a simulation experiment is designed to verify the effectiveness and robustness of ASTF. A sensitive evaluation method using principal component analysis (PCA) is proposed to evaluate the sensitiveness of symptom parameters (SPs) for condition diagnosis. By this way, the good SPs that have high sensitiveness for condition diagnosis can be selected. A three-layer DBN is developed to identify condition of rotation machinery based on the Bayesian Belief Network (BBN) theory. Condition diagnosis experiment for rolling element bearings demonstrates the effectiveness of the proposed method. PMID:26761006

  7. Adaptation of a primate operant test battery to the rat: effects of chlorpromazine.

    PubMed

    Mayorga, A J; Popke, E J; Fogle, C M; Paule, M G

    2000-01-01

    The National Center for Toxicological Research (NCTR) Operant Test Battery (OTB) has been used extensively in rhesus monkeys to characterize the effects of drugs and toxicants on the performance of tasks designed to model several cognitive functions. Recently, the majority of the OTB tasks have been adapted for use in rats. The current study is the first to examine the effects of a prototypic pharmacological agent previously assessed in monkeys on rat OTB performance. The effects of the dopamine antagonist chlorpromazine (0.56-5.6 mg/kg, i.p.) were assessed in rats performing tasks designed to model auditory-visual-position discrimination, learning, time estimation, and appetitive motivation. All four tasks were equally sensitive to the behavioral effects of chlorpromazine. This pattern of sensitivity was very similar to that obtained when chlorpromazine was tested in monkeys performing the OTB. These data thus suggest that operant tasks designed to model cognitive functions in monkeys can also be used in rats, and that the effects of chlorpromazine on the performance of these tasks may be predictive of results obtained with monkeys. Further characterization of the rat OTB using prototypic pharmacological agents will further determine the extent to which drug effects on rat OTB performance can be generalized to primates.

  8. Intelligent Condition Diagnosis Method Based on Adaptive Statistic Test Filter and Diagnostic Bayesian Network.

    PubMed

    Li, Ke; Zhang, Qiuju; Wang, Kun; Chen, Peng; Wang, Huaqing

    2016-01-08

    A new fault diagnosis method for rotating machinery based on adaptive statistic test filter (ASTF) and Diagnostic Bayesian Network (DBN) is presented in this paper. ASTF is proposed to obtain weak fault features under background noise, ASTF is based on statistic hypothesis testing in the frequency domain to evaluate similarity between reference signal (noise signal) and original signal, and remove the component of high similarity. The optimal level of significance α is obtained using particle swarm optimization (PSO). To evaluate the performance of the ASTF, evaluation factor Ipq is also defined. In addition, a simulation experiment is designed to verify the effectiveness and robustness of ASTF. A sensitive evaluation method using principal component analysis (PCA) is proposed to evaluate the sensitiveness of symptom parameters (SPs) for condition diagnosis. By this way, the good SPs that have high sensitiveness for condition diagnosis can be selected. A three-layer DBN is developed to identify condition of rotation machinery based on the Bayesian Belief Network (BBN) theory. Condition diagnosis experiment for rolling element bearings demonstrates the effectiveness of the proposed method.

  9. Testing for conflicting and nonadditive selection: floral adaptation to multiple pollinators through male and female fitness.

    PubMed

    Sahli, Heather F; Conner, Jeffrey K

    2011-05-01

    Although conflicting selection from different resources is thought to play a critical role in the evolution of specialized species, the prevalence of conflicting selection in generalists is poorly understood. Plants may experience conflicting selection on floral traits by different pollinators and between genders. Using artificial selection to increase phenotypic variation, we tested for conflicting and nonadditive selection on wild radish (Raphanus raphanistrum) flowers. To do this, we measured selection by each of the major pollinator taxa through both male and female fitness, and tested for a single-generation response to selection by a subset of these pollinators. We found some evidence for conflicting selection on anther exertion--sweat bees exerted stabilizing selection and larger bees selected for increased exertion. Stamen dimorphism was only under selection by honey bees, causing a response to selection in the next generation, and flower size was under similar selection by multiple pollinators. Selection differed significantly between genders for two traits, but there was no evidence for stronger selection through male fitness or for conflicting selection between genders. Our results suggest wild radish flowers can adapt to multiple pollinators, as we found little evidence for conflicting selection and no evidence for nonadditive selection among pollinators.

  10. FLAGS: A Flexible and Adaptive Association Test for Gene Sets Using Summary Statistics

    PubMed Central

    Huang, Jianfei; Wang, Kai; Wei, Peng; Liu, Xiangtao; Liu, Xiaoming; Tan, Kai; Boerwinkle, Eric; Potash, James B.; Han, Shizhong

    2016-01-01

    Genome-wide association studies (GWAS) have been widely used for identifying common variants associated with complex diseases. Despite remarkable success in uncovering many risk variants and providing novel insights into disease biology, genetic variants identified to date fail to explain the vast majority of the heritability for most complex diseases. One explanation is that there are still a large number of common variants that remain to be discovered, but their effect sizes are generally too small to be detected individually. Accordingly, gene set analysis of GWAS, which examines a group of functionally related genes, has been proposed as a complementary approach to single-marker analysis. Here, we propose a flexible and adaptive test for gene sets (FLAGS), using summary statistics. Extensive simulations showed that this method has an appropriate type I error rate and outperforms existing methods with increased power. As a proof of principle, through real data analyses of Crohn’s disease GWAS data and bipolar disorder GWAS meta-analysis results, we demonstrated the superior performance of FLAGS over several state-of-the-art association tests for gene sets. Our method allows for the more powerful application of gene set analysis to complex diseases, which will have broad use given that GWAS summary results are increasingly publicly available. PMID:26773050

  11. Cross-Cultural Adaptation and Psychometric Properties Testing of the Arabic Anterior Knee Pain Scale.

    PubMed

    Alshehri, Abdullah; Lohman, Everett; Daher, Noha S; Bahijri, Khalid; Alghamdi, Abdulmohsen; Altorairi, Nezar; Arnons, Arin; Matar, Abdullah

    2017-04-01

    BACKGROUND PFPS is one of the most frequently occurring overuse injuries affecting the lower limbs. A variety of functional and self-reported outcome measures have been used to assess clinical outcomes of patients with PFPS, however, only the Anterior Knee Pain Scale (AKPS) has been designed for PFPS patients. MATERIAL AND METHODS We followed international recommendations to perform a cross-cultural adaptation of the AKPS. The Arabic AKPS and the Arabic RAND 36-item Health Survey were administered to 40 patients who were diagnosed with PFPS. Participants were assessed at baseline and after 2 to 3 days assessed with the Arabic AKPS only. The measurements tested were reliability, validity, and feasibility. RESULTS The Arabic AKPS showed high reliability for both temporal stability, internal consistency (Cronbach's alpha was 0.81 for the first assessment and 0.75 for the second), excellent test-retest reliability (Intraclass Correlation Coefficients ICC=0.96; 95% confidence interval (CI): 0.93, 0.98) and good agreement (standard error of measurement SEM=1.8%). The Arabic AKPS was significantly correlated with physical components of the RAND 36-Item Health Survey (Spearman's rho=0.69: p<0.001). No ceiling or floor effects were observed. CONCLUSIONS The Arabic AKPS is a valid and reliable tool and is comparable to the original English version and other translated versions.

  12. P-method post hoc test for adaptive trimmed mean, HQ

    NASA Astrophysics Data System (ADS)

    Low, Joon Khim; Yahaya, Sharipah Soaad Syed; Abdullah, Suhaida; Yusof, Zahayu Md; Othman, Abdul Rahman

    2014-12-01

    Adaptive trimmed mean, HQ, which is one of the latest additions in robust estimators, had been proven to be good in controlling Type I error in omnibus test. However, post hoc (pairwise multiple comparison) procedure for HQ was yet to be developed then. Thus, we have taken the initiative to develop post hoc procedure for HQ. Percentile bootstrap method or P-Method was proposed as it was proven to be effective in controlling Type I error rate even when the sample size was small. This paper deliberates on the effectiveness of P-Method on HQ, denoted as P-HQ. The strength and weakness of the proposed method were put to test on various conditions created by manipulating several variables such as shape of distributions, number of groups, sample sizes, degree of variance heterogeneity and pairing of sample sizes and group variances. For such, a simulation study on 2000 datasets was conducted using SAS/IML Version 9.2. The performance of the method on various conditions was based on its ability in controlling Type I error which was benchmarked using Bradley's criterion of robustness. The finding revealed that P-HQ could effectively control Type I error for almost all the conditions investigated.

  13. Cross-Cultural Adaptation and Psychometric Properties Testing of the Arabic Anterior Knee Pain Scale

    PubMed Central

    Alshehri, Abdullah; Lohman, Everett; Daher, Noha S.; Bahijri, Khalid; Alghamdi, Abdulmohsen; Altorairi, Nezar; Arnos, Arin; Matar, Abdullah

    2017-01-01

    Background PFPS is one of the most frequently occurring overuse injuries affecting the lower limbs. A variety of functional and self-reported outcome measures have been used to assess clinical outcomes of patients with PFPS, however, only the Anterior Knee Pain Scale (AKPS) has been designed for PFPS patients. Material/Methods We followed international recommendations to perform a cross-cultural adaptation of the AKPS. The Arabic AKPS and the Arabic RAND 36-item Health Survey were administered to 40 patients who were diagnosed with PFPS. Participants were assessed at baseline and after 2 to 3 days assessed with the Arabic AKPS only. The measurements tested were reliability, validity, and feasibility. Results The Arabic AKPS showed high reliability for both temporal stability, internal consistency (Cronbach’s alpha was 0.81 for the first assessment and 0.75 for the second), excellent test-retest reliability (Intraclass Correlation Coefficients ICC=0.96; 95% confidence interval (CI): 0.93, 0.98) and good agreement (standard error of measurement SEM=1.8%). The Arabic AKPS was significantly correlated with physical components of the RAND 36-Item Health Survey (Spearman’s rho=0.69: p<0.001). No ceiling or floor effects were observed. Conclusions The Arabic AKPS is a valid and reliable tool and is comparable to the original English version and other translated versions. PMID:28364114

  14. Method for production of carbon nanofiber mat or carbon paper

    DOEpatents

    Naskar, Amit K.

    2015-08-04

    Method for the preparation of a non-woven mat or paper made of carbon fibers, the method comprising carbonizing a non-woven mat or paper preform (precursor) comprised of a plurality of bonded sulfonated polyolefin fibers to produce said non-woven mat or paper made of carbon fibers. The preforms and resulting non-woven mat or paper made of carbon fiber, as well as articles and devices containing them, and methods for their use, are also described.

  15. Biomimetic evolutionary analysis: testing the adaptive value of vertebrate tail stiffness in autonomous swimming robots.

    PubMed

    Long, J H; Koob, T J; Irving, K; Combie, K; Engel, V; Livingston, N; Lammert, A; Schumacher, J

    2006-12-01

    For early vertebrates, a long-standing hypothesis is that vertebrae evolved as a locomotor adaptation, stiffening the body axis and enhancing swimming performance. While supported by biomechanical data, this hypothesis has not been tested using an evolutionary approach. We did so by extending biomimetic evolutionary analysis (BEA), which builds physical simulations of extinct systems, to include use of autonomous robots as proxies of early vertebrates competing in a forage navigation task. Modeled after free-swimming larvae of sea squirts (Chordata, Urochordata), three robotic tadpoles (;Tadros'), each with a propulsive tail bearing a biomimetic notochord of variable spring stiffness, k (N m(-1)), searched for, oriented to, and orbited in two dimensions around a light source. Within each of ten generations, we selected for increased swimming speed, U (m s(-1)) and decreased time to the light source, t (s), average distance from the source, R (m) and wobble maneuvering, W (rad s(-2)). In software simulation, we coded two quantitative trait loci (QTL) that determine k: bending modulus, E (Nm(-2)) and length, L (m). Both QTL were mutated during replication, independently assorted during meiosis and, as haploid gametes, entered into the gene pool in proportion to parental fitness. After random mating created three new diploid genotypes, we fabricated three new offspring tails. In the presence of both selection and chance events (mutation, genetic drift), the phenotypic means of this small population evolved. The classic hypothesis was supported in that k was positively correlated (r(2)=0.40) with navigational prowess, NP, the dimensionless ratio of U to the product of R, t and W. However, the plausible adaptive scenario, even in this simplified system, is more complex, since the remaining variance in NP was correlated with the residuals of R and U taken with respect to k, suggesting that changes in k alone are insufficient to explain the evolution of NP.

  16. Closing the design loop on HiMAT (highly maneuverable aircraft technology)

    NASA Technical Reports Server (NTRS)

    Putnam, T. W.; Robinson, M. R.

    1984-01-01

    The design methodology used in the HiMAT program and the wind tunnel development activities are discussed. Selected results from the flight test program are presented and the strengths and weaknesses of testing advanced technology vehicles using the RPV concept is examined. The role of simulation on the development of digital flight control systems and in RPV's in particular is emphasized.

  17. Diversity techniques for omnidirectional telemetry coverage of the HiMAT research vehicle

    NASA Technical Reports Server (NTRS)

    Harney, P. F.

    1981-01-01

    The highly maneuverable aircraft technology (HiMAT) remotely piloted research vehicle (RPRV) was flight tested and a number of technological advances applicable to future fighter aircraft were demonstrated. The aircraft control system uses airborne and ground-based computers which communicate via uplink and downlink telemetry. Antenna radiation patterns are normally much less than ideal for continuous reception or transmission for all aircraft attitudes. After flight qualification and testing on other aircraft, a frequency diversity concept and an antenna diversity concept were implemented on the HiMAT vehicle to obtain omnidirectional telemetry coverage.

  18. Determination of Judo Endurance Performance Using the Uchi - Komi Technique and an Adapted Lactate Minimum Test

    PubMed Central

    Azevedo, Paulo H.S.M.; Drigo, Alexandre J.; Carvalho, Mauro C.G.A.; Oliveira, João C.; Nunes, João E.D.; Baldissera, Vilmar; Perez, Sérgio E.A.

    2007-01-01

    This study aimed to evaluate the viability to use Uchi-komi (UK) in the evaluation of the judo endurance performance and using lactate threshold the analysis of the blood lactate ([Lac]) and heart rate (HR) determined through a lactate minimum test. The subjects were a group of 6 male, volunteer judokas, from 25.17 ± 5.76 years old, weight 84.50 ± 23.78 kg and height 1.78 ± 0.10 m, competitors of different levels of performance (from regional to international competitions) and match experience of (11 ± 6) years old. Three tests were performed: a) 3000 m dash in track, b) the adapted test of lactate minimum for running and c) for UK, with execution of the blow ippon-seoi-nague. No significant difference was evident for the track tests and UK in relation to blood lactate and heart rate (p > 0.05) (3.87 ± 0.38 vs 4.17 ± 0.54 mmol·L-1 and 167 ± 2 vs 152 ± 7 b·min-1, respectively). In conclusion it is stressed that: 1) The specific test for lactate minimum in judo sport is a promising possibility of aerobic capacity evaluation and a instrument of intensity training control; 2) The metabolic profile in Vlm and UKlm is similar, because there are not differences in the [Lac] and in the HR at this intensity; 3) It is possible to estimate the training intensity through the determination of the lactate minimum intensity in running (Vlm) and the Heart Rate associated (HR) from the execution of ippon-seoi- nague (uchi-komi) in judo training; 4) The Vlm for judo athletes is approximately 88% of the V3000. Key points The specific test for lactate minimum in judo sport is a promising possibility of aerobic capacity evaluation; This is a instrument for intensity training control for judo players; The metabolic profile is similar between running and uki-komi (ippon-seoi-nague techniques) at lactate minimum intensity. PMID:24198697

  19. Cortisol profiles: A test for adaptive calibration of the stress response system in maltreated and nonmaltreated youth

    PubMed Central

    PECKINS, MELISSA K.; SUSMAN, ELIZABETH J.; NEGRIFF, SONYA; NOLL, JENNIE; TRICKETT, PENELOPE K.

    2017-01-01

    Throughout the life span, exposure to chronic stress such as child maltreatment is thought to contribute to future dysfunction of the stress response system (SRS) through the process of adaptive calibration. Dysfunction of the SRS is associated with numerous health and behavior problems, so it is important to understand under what conditions and what time frame adaptive calibration occurs. The present study tested for adaptive calibration of the SRS in a sample of maltreated (n = 303) and nonmaltreated (n = 151) youth during the important developmental period of adolescence. Data were used from Waves 2, 3, and 4 of a larger study of the consequences of maltreatment on health and well-being. At each time point, participants underwent the Trier Social Stress Test for Children and provided a baseline and four poststressor saliva samples to measure cortisol reactivity. Adaptive calibration was tested by performing a latent profile analysis using the five samples of salivary cortisol provided at each time point, and testing whether maltreatment status predicted the likelihood of profile membership at Time 2, Time 3, and Time 4. Three cortisol profiles emerged from the data at each time point (blunted, moderate, and elevated), and results indicated that maltreated youth were more likely than nonmaltreated youth to present with the blunted cortisol profile compared to the moderate and elevated profiles at Time 2 and Time 3, even after controlling for recent exposure to violence and trauma. At Time 4, there was no longer a difference in profile membership between maltreated and nonmaltreated youth, suggesting adaptive calibration may be a lengthy process requiring a period of years to become evident. Overall, the findings provide support for adaptive calibration and offer insight into the conditions under which adaptive calibration occurs. PMID:26535937

  20. MAT - MULTI-ATTRIBUTE TASK BATTERY FOR HUMAN OPERATOR WORKLOAD AND STRATEGIC BEHAVIOR RESEARCH

    NASA Technical Reports Server (NTRS)

    Comstock, J. R.

    1994-01-01

    MAT, a Multi-Attribute Task battery, gives the researcher the capability of performing multi-task workload and performance experiments. The battery provides a benchmark set of tasks for use in a wide range of laboratory studies of operator performance and workload. MAT incorporates tasks analogous to activities that aircraft crew members perform in flight, while providing a high degree of experiment control, performance data on each subtask, and freedom to use non-pilot test subjects. The MAT battery primary display is composed of four separate task windows which are as follows: a monitoring task window which includes gauges and warning lights, a tracking task window for the demands of manual control, a communication task window to simulate air traffic control communications, and a resource management task window which permits maintaining target levels on a fuel management task. In addition, a scheduling task window gives the researcher information about future task demands. The battery also provides the option of manual or automated control of tasks. The task generates performance data for each subtask. The task battery may be paused and onscreen workload rating scales presented to the subject. The MAT battery was designed to use a serially linked second computer to generate the voice messages for the Communications task. The MATREMX program and support files, which are included in the MAT package, were designed to work with the Heath Voice Card (Model HV-2000, available through the Heath Company, Benton Harbor, Michigan 49022); however, the MATREMX program and support files may easily be modified to work with other voice synthesizer or digitizer cards. The MAT battery task computer may also be used independent of the voice computer if no computer synthesized voice messages are desired or if some other method of presenting auditory messages is devised. MAT is written in QuickBasic and assembly language for IBM PC series and compatible computers running MS-DOS. The

  1. Testing vision with angular and radial multifocal designs using Adaptive Optics.

    PubMed

    Vinas, Maria; Dorronsoro, Carlos; Gonzalez, Veronica; Cortes, Daniel; Radhakrishnan, Aiswaryah; Marcos, Susana

    2017-03-01

    Multifocal vision corrections are increasingly used solutions for presbyopia. In the current study we have evaluated, optically and psychophysically, the quality provided by multizone radial and angular segmented phase designs. Optical and relative visual quality were evaluated using 8 subjects, testing 6 phase designs. Optical quality was evaluated by means of Visual Strehl-based-metrics (VS). The relative visual quality across designs was obtained through a psychophysical paradigm in which images viewed through 210 pairs of phase patterns were perceptually judged. A custom-developed Adaptive Optics (AO) system, including a Hartmann-Shack sensor and an electromagnetic deformable mirror, to measure and correct the eye's aberrations, and a phase-only reflective Spatial Light Modulator, to simulate the phase designs, was developed for this study. The multizone segmented phase designs had 2-4 zones of progressive power (0 to +3D) in either radial or angular distributions. The response of an "ideal observer" purely responding on optical grounds to the same psychophysical test performed on subjects was calculated from the VS curves, and compared with the relative visual quality results. Optical and psychophysical pattern-comparison tests showed that while 2-zone segmented designs (angular & radial) provided better performance for far and near vision, 3- and 4-zone segmented angular designs performed better for intermediate vision. AO-correction of natural aberrations of the subjects modified the response for the different subjects but general trends remained. The differences in perceived quality across the different multifocal patterns are, in a large extent, explained by optical factors. AO is an excellent tool to simulate multifocal refractions before they are manufactured or delivered to the patient, and to assess the effects of the native optics to their performance.

  2. Goodness-of-Fit Tests and Nonparametric Adaptive Estimation for Spike Train Analysis

    PubMed Central

    2014-01-01

    When dealing with classical spike train analysis, the practitioner often performs goodness-of-fit tests to test whether the observed process is a Poisson process, for instance, or if it obeys another type of probabilistic model (Yana et al. in Biophys. J. 46(3):323–330, 1984; Brown et al. in Neural Comput. 14(2):325–346, 2002; Pouzat and Chaffiol in Technical report, http://arxiv.org/abs/arXiv:0909.2785, 2009). In doing so, there is a fundamental plug-in step, where the parameters of the supposed underlying model are estimated. The aim of this article is to show that plug-in has sometimes very undesirable effects. We propose a new method based on subsampling to deal with those plug-in issues in the case of the Kolmogorov–Smirnov test of uniformity. The method relies on the plug-in of good estimates of the underlying model that have to be consistent with a controlled rate of convergence. Some nonparametric estimates satisfying those constraints in the Poisson or in the Hawkes framework are highlighted. Moreover, they share adaptive properties that are useful from a practical point of view. We show the performance of those methods on simulated data. We also provide a complete analysis with these tools on single unit activity recorded on a monkey during a sensory-motor task. Electronic Supplementary Material The online version of this article (doi:10.1186/2190-8567-4-3) contains supplementary material. PMID:24742008

  3. Goodness-of-Fit Tests and Nonparametric Adaptive Estimation for Spike Train Analysis.

    PubMed

    Reynaud-Bouret, Patricia; Rivoirard, Vincent; Grammont, Franck; Tuleau-Malot, Christine

    2014-04-17

    When dealing with classical spike train analysis, the practitioner often performs goodness-of-fit tests to test whether the observed process is a Poisson process, for instance, or if it obeys another type of probabilistic model (Yana et al. in Biophys. J. 46(3):323-330, 1984; Brown et al. in Neural Comput. 14(2):325-346, 2002; Pouzat and Chaffiol in Technical report, http://arxiv.org/abs/arXiv:0909.2785, 2009). In doing so, there is a fundamental plug-in step, where the parameters of the supposed underlying model are estimated. The aim of this article is to show that plug-in has sometimes very undesirable effects. We propose a new method based on subsampling to deal with those plug-in issues in the case of the Kolmogorov-Smirnov test of uniformity. The method relies on the plug-in of good estimates of the underlying model that have to be consistent with a controlled rate of convergence. Some nonparametric estimates satisfying those constraints in the Poisson or in the Hawkes framework are highlighted. Moreover, they share adaptive properties that are useful from a practical point of view. We show the performance of those methods on simulated data. We also provide a complete analysis with these tools on single unit activity recorded on a monkey during a sensory-motor task.Electronic Supplementary MaterialThe online version of this article (doi:10.1186/2190-8567-4-3) contains supplementary material.

  4. A free gift: an adaptive strategy in a single-arm trial using an exact test through the binomial distribution.

    PubMed

    Wang, Jin

    2012-01-01

    For medical product development within the same generation, single-arm trial designs are commonly implemented to test the performance of the new product against an objective performance criterion. When the primary endpoint is binary and the sample size is moderate, an exact test through the binomial distribution is usually used. This article shows that it is a free gift to add an adaptive component to a fixed-sample-size design so that when the interim result is marginal, the adaptive feature can be activated without any penalty. A hypothetical example is used to illustrate the application of this method.

  5. Systematic testing of flood adaptation options in urban areas through simulations

    NASA Astrophysics Data System (ADS)

    Löwe, Roland; Urich, Christian; Sto. Domingo, Nina; Mark, Ole; Deletic, Ana; Arnbjerg-Nielsen, Karsten

    2016-04-01

    While models can quantify flood risk in great detail, the results are subject to a number of deep uncertainties. Climate dependent drivers such as sea level and rainfall intensities, population growth and economic development all have a strong influence on future flood risk, but future developments can only be estimated coarsely. In such a situation, robust decision making frameworks call for the systematic evaluation of mitigation measures against ensembles of potential futures. We have coupled the urban development software DAnCE4Water and the 1D-2D hydraulic simulation package MIKE FLOOD to create a framework that allows for such systematic evaluations, considering mitigation measures under a variety of climate futures and urban development scenarios. A wide spectrum of mitigation measures can be considered in this setup, ranging from structural measures such as modifications of the sewer network over local retention of rainwater and the modification of surface flow paths to policy measures such as restrictions on urban development in flood prone areas or master plans that encourage compact development. The setup was tested in a 300 ha residential catchment in Melbourne, Australia. The results clearly demonstrate the importance of considering a range of potential futures in the planning process. For example, local rainwater retention measures strongly reduce flood risk a scenario with moderate increase of rain intensities and moderate urban growth, but their performance strongly varies, yielding very little improvement in situations with pronounced climate change. The systematic testing of adaptation measures further allows for the identification of so-called adaptation tipping points, i.e. levels for the drivers of flood risk where the desired level of flood risk is exceeded despite the implementation of (a combination of) mitigation measures. Assuming a range of development rates for the drivers of flood risk, such tipping points can be translated into

  6. Distribution of cultivated and uncultivated cyanobacteria and Chloroflexus-like bacteria in hot spring microbial mats

    NASA Technical Reports Server (NTRS)

    Ruff-Roberts, A. L.; Kuenen, J. G.; Ward, D. M.

    1994-01-01

    Oligodeoxynucleotide hybridization probes were developed to complement specific regions of the small subunit (SSU) rRNA sequences of cultivated and uncultivated cyanobacteria and Chloroflexus-like bacteria, which inhabit hot spring microbial mats. The probes were used to investigate the natural distribution of SSU rRNAs from these species in mats of Yellowstone hot springs of different temperatures and pHs as well as changes in SSU rRNA distribution resulting from 1-week in situ shifts in temperature, pH, and light intensity. Synechococcus lividus Y-7c-s SSU rRNA was detected only in the mat of a slightly acid spring, from which it may have been initially isolated, or when samples from a more alkaline spring were incubated in the more acid spring. Chloroflexus aurantiacus Y-400-fl SSU rRNA was detected only in a high-temperature mat sample from the alkaline Octopus Spring or when lower-temperature samples from this mat were incubated at the high-temperature site. SSU rRNAs of uncultivated species were more widely distributed. Temperature distributions and responses to in situ temperature shifts suggested that some of the uncultivated cyanobacteria might be adapted to high-, moderate-, and low-temperature ranges whereas an uncultivated Chloroflexus-like bacterium appears to have broad temperature tolerance. SSU rRNAs of all uncultivated species inhabiting a 48 to 51 degrees C Octopus Spring mat site were most abundant in the upper 1 mm and were not detected below a 2.5-to 3.5-mm depth, a finding consistent with their possible phototrophic nature. However, the effects of light intensity reduction on these SSU rRNAs were variable, indicating the difficulty of demonstrating a phototrophic phenotype in light reduction experiments.

  7. Non-woven nanofiber mats - a new perspective for experimental studies of the central nervous system?

    PubMed

    Rafalowska, Janina; Sulejczak, Dorota; Chrapusta, Stanisław J; Gadamski, Roman; Taraszewska, Anna; Nakielski, Paweł; Kowalczyk, Tomasz; Dziewulska, Dorota

    2014-01-01

    (Sub)chronic local drug application is clearly superior to systemic administration, but may be associated with substantial obstacles, particularly regarding the applications to highly sensitive central nervous system (CNS) structures that are shielded from the outer environment by the blood-brain barrier. Violation of the integrity of the barrier and CNS tissues by a permanently implanted probe or cannula meant for prolonged administration of drugs into specific CNS structures can be a severe confounding factor because of the resulting inflammatory reactions. In this study, we tested the utility of a novel way for (sub)chronic local delivery of highly active (i.e., used in very low amounts) drugs to the rat spinal cord employing a non-woven nanofiber mat dressing. To this end, we compared the morphology and motoneuron ( + ) counts in spinal cord cervical and lumbar segments between rats with glutamate-loaded nanofiber mats applied to the lumbar enlargement and rats with analogical implants carrying no glutamate. Half of the rats with glutamate-loaded implants were given daily valproate treatment to test its potential for counteracting the detrimental effects of glutamate excess. The mats were prepared in-house by electrospinning of an emulsion made of a solution of the biocompatible and biodegradable poly(L-lactide-co-caprolactone) polymer in a mixture of organic solvents, an aqueous phase with or without monosodium glutamate, and sodium dodecyl sulfate as an emulsifier; the final glutamate content was 1.4 µg/mg of the mat. Three weeks after mat implantation there was no inflammation or considerable damage of the spinal cord motoneuron population in the rats with the subarachnoid dressing of a glutamate-free mat, whereas the spinal cords of the rats with glutamate-loaded nanofiber mats showed clear symptoms of excitotoxic damage and a substantial increase in dying/damaged motoneuron numbers in both segments studied. The rats given systemic valproate

  8. Applying Computerized Adaptive Testing to the Negative Acts Questionnaire-Revised: Rasch Analysis of Workplace Bullying

    PubMed Central

    Ma, Shu-Ching; Li, Yu-Chi; Yui, Mei-Shu

    2014-01-01

    Background Workplace bullying is a prevalent problem in contemporary work places that has adverse effects on both the victims of bullying and organizations. With the rapid development of computer technology in recent years, there is an urgent need to prove whether item response theory–based computerized adaptive testing (CAT) can be applied to measure exposure to workplace bullying. Objective The purpose of this study was to evaluate the relative efficiency and measurement precision of a CAT-based test for hospital nurses compared to traditional nonadaptive testing (NAT). Under the preliminary conditions of a single domain derived from the scale, a CAT module bullying scale model with polytomously scored items is provided as an example for evaluation purposes. Methods A total of 300 nurses were recruited and responded to the 22-item Negative Acts Questionnaire-Revised (NAQ-R). All NAT (or CAT-selected) items were calibrated with the Rasch rating scale model and all respondents were randomly selected for a comparison of the advantages of CAT and NAT in efficiency and precision by paired t tests and the area under the receiver operating characteristic curve (AUROC). Results The NAQ-R is a unidimensional construct that can be applied to measure exposure to workplace bullying through CAT-based administration. Nursing measures derived from both tests (CAT and NAT) were highly correlated (r=.97) and their measurement precisions were not statistically different (P=.49) as expected. CAT required fewer items than NAT (an efficiency gain of 32%), suggesting a reduced burden for respondents. There were significant differences in work tenure between the 2 groups (bullied and nonbullied) at a cutoff point of 6 years at 1 worksite. An AUROC of 0.75 (95% CI 0.68-0.79) with logits greater than –4.2 (or >30 in summation) was defined as being highly likely bullied in a workplace. Conclusions With CAT-based administration of the NAQ-R for nurses, their burden was substantially

  9. Ecophysiological Changes in Microbial Mats Incubated in a Greenhouse Collaboratory

    NASA Technical Reports Server (NTRS)

    Bebout, Brad; DesMarais, David J.; GarciaPichel, Ferran; Hogan, Mary; Jahnke, Linda; Keller, Richard M.; Miller, Scott R.

    2001-01-01

    Microbial mats are modern examples of the earliest microbial communities known. Among the best studied are microbial mats growing in hypersaline ponds managed for the production of salt by Exportadora de Sal, S.A. de C.V., Guerrero Negro, Baja California Sur, Mexico. In May, 2001, we collected mats from Ponds 4 and 5 in this system and returned them to Ames Research Center, where they have been maintained for a period of over nine months. We report here on both the ecophysiological changes occurring in the mats over that period of time as well as the facility in which they were incubated. Mats (approximately 1 sq. meter total area) were incubated in a greenhouse facility modified to provide the mats with natural levels of visible and ultraviolet radiation as well as constantly flowing, temperature-controlled water. Two replicated treatments were maintained, a 'high salinity' treatment (about 120 ppt) and a 'low salinity' treatment (about 90 ppt). Rates of net biological activity (e.g., photosynthesis, respiration, trace gas production) in the mats were relatively constant over the several months, and were similar to rates of activity measured in the field. However, over the course of the incubation, mats in both treatments changed in physical appearance. The most obvious change was that mats in the higher salinity treatments developed a higher proportion of carotenoid pigments (relative to chlorophyll), resulting in a noticeably orange color in the high salinity mats. This trend is also seen in the natural salinity gradient present at the field site. Changes in the community composition of the mats, as assayed by denaturing gradient gel electrophoresis (DGGE), as well as biomarker compounds produced in the mats were also monitored. The degree to which the mats kept in the greenhouse changed from the originally collected mats, as well as differences between high and low salinity mats will be discussed. Additional information is contained in the original extended

  10. Flight Test of an Adaptive Controller and Simulated Failure/Damage on the NASA NF-15B

    NASA Technical Reports Server (NTRS)

    Buschbacher, Mark; Maliska, Heather

    2006-01-01

    The method of flight-testing the Intelligent Flight Control System (IFCS) Second Generation (Gen-2) project on the NASA NF-15B is herein described. The Gen-2 project objective includes flight-testing a dynamic inversion controller augmented by a direct adaptive neural network to demonstrate performance improvements in the presence of simulated failure/damage. The Gen-2 objectives as implemented on the NASA NF-15B created challenges for software design, structural loading limitations, and flight test operations. Simulated failure/damage is introduced by modifying control surface commands, therefore requiring structural loads measurements. Flight-testing began with the validation of a structural loads model. Flight-testing of the Gen-2 controller continued, using test maneuvers designed in a sequenced approach. Success would clear the new controller with respect to dynamic response, simulated failure/damage, and with adaptation on and off. A handling qualities evaluation was conducted on the capability of the Gen-2 controller to restore aircraft response in the presence of a simulated failure/damage. Control room monitoring of loads sensors, flight dynamics, and controller adaptation, in addition to postflight data comparison to the simulation, ensured a safe methodology of buildup testing. Flight-testing continued without major incident to accomplish the project objectives, successfully uncovering strengths and weaknesses of the Gen-2 control approach in flight.

  11. Using a "time machine" to test for local adaptation of aquatic microbes to temporal and spatial environmental variation.

    PubMed

    Fox, Jeremy W; Harder, Lawrence D

    2015-01-01

    Local adaptation occurs when different environments are dominated by different specialist genotypes, each of which is relatively fit in its local conditions and relatively unfit under other conditions. Analogously, ecological species sorting occurs when different environments are dominated by different competing species, each of which is relatively fit in its local conditions. The simplest theory predicts that spatial, but not temporal, environmental variation selects for local adaptation (or generates species sorting), but this prediction is difficult to test. Although organisms can be reciprocally transplanted among sites, doing so among times seems implausible. Here, we describe a reciprocal transplant experiment testing for local adaptation or species sorting of lake bacteria in response to both temporal and spatial variation in water chemistry. The experiment used a -80°C freezer as a "time machine." Bacterial isolates and water samples were frozen for later use, allowing transplantation of older isolates "forward in time" and newer isolates "backward in time." Surprisingly, local maladaptation predominated over local adaptation in both space and time. Such local maladaptation may indicate that adaptation, or the analogous species sorting process, fails to keep pace with temporal fluctuations in water chemistry. This hypothesis could be tested with more finely resolved temporal data.

  12. Effects of Age and Cognition on a Cross-Cultural Paediatric Adaptation of the Sniffin' Sticks Identification Test

    PubMed Central

    Guerreiro, Marilisa Mantovani; Lees, Andrew John; Warner, Thomas T.

    2015-01-01

    Objectives To study the effects of age and cognition on the performance of children aged 3 to 18 years on a culturally adapted version of the 16 item smell identification test from Sniffin' Sticks (SS16). Methods A series of pilots were conducted on 29 children aged 3 to 18 years old and 23 adults to produce an adapted version of the SS16 suitable for Brazilian children (SS16-Child). A final version was applied to 51 children alongside a picture identification test (PIT-SS16-Child) to access cognitive abilities involved in the smell identification task. In addition 20 adults performed the same tasks as a comparison group. Results The final adapted SS16-Child was applied to 51 children with a mean age of 9.9 years (range 3-18 years, SD=4.25 years), of which 68.3% were girls. There was an independent effect of age (p<0.05) and PIT-SS16-Child (p<0.001) on the performance on the SS16-Child, and older children reached the ceiling for scoring in the cognitive and olfactory test. Pre-school children had difficulties identifying items of the test. Discussion/Conclusions A cross-culturally adapted version of the SS16 can be used to test olfaction in children but interpretation of the results must take age and cognitive abilities into consideration. PMID:26267145

  13. ChemMatCARS Data Archive

    DOE Data Explorer

    ChemMatCARS is a high-brilliance national synchrotron x-ray facility dedicated primarily to static and dynamic condensed matter chemistry and materials science. The scientific focus of the facility includes the study of surface and interfacial properties of liquids and solids as well as their bulk structure at atomic, molecular and mesoscopic length scales with high spatial and energy resolution. Experimental techniques supported by the facility include: 1) Liquid Surface X-ray Scattering; 2) Solid Surface X-ray Scattering; 3) Time-Resolved Crystallography; 4) Micro-Crystal Diffraction; 5) Small and Wide-angle X-ray Scattering. The data archive referenced here contains data for various components along the beamline within the First Optics Enclosure and is intended to be input or parameter data. See the Science Nuggets at http://cars9.uchicago.edu/chemmat/pages/nuggets.html for leads to some of the research conducted at the ChemMatCARS beamline.

  14. Microbial mats: an ecological niche for fungi

    PubMed Central

    Cantrell, Sharon A.; Duval-Pérez, Lisabeth

    2013-01-01

    Fungi were documented in tropical hypersaline microbial mats and their role in the degradation of complex carbohydrates (exopolymeric substance – EPS) was explored. Fungal diversity is higher during the wet season with Acremonium, Aspergillus, Cladosporium, and Penicillium among the more common genera. Diversity is also higher in the oxic layer and in young and transient mats. Enrichments with xanthan (a model EPS) show that without antibiotics (full community) degradation is faster than enrichments with antibacterial (fungal community) and antifungal (bacterial community) agents, suggesting that degradation is performed by a consortium of organisms (bacteria and fungi). The combined evidence from all experiments indicates that bacteria carried out approximately two-third of the xanthan degradation. The pattern of degradation is similar between seasons and layers but degradation is faster in enrichments from the wet season. The research suggests that fungi thrive in these hypersaline consortia and may participate in the carbon cycle through the degradation of complex carbohydrates. PMID:23577004

  15. Bioflumology: Microbial mat growth in flumes

    NASA Astrophysics Data System (ADS)

    Airo, A.; Weigert, S.; Beck, C.

    2014-04-01

    The emergence of oxygenic photosynthesis resulted in a transformational change of Earth's geochemical cycles and the subsequent evolution of life. However, it remains vigorously debated when this metabolic ability had evolved in cyanobacteria. This is largely because studies of Archean microfossil morphology, molecular biomarkers, and isotopic characteristics are frequently ambiguous. However, the high degree of morphological similarities between modern photosynthetic and Archean fossil mats has been interpreted to indicate phototactic microbial behavior or oxygenic photosynthesis. In order to better evaluate the relationship between mat morphology and metabolism, we here present a laboratory set-up for conducting month-long experiments in several sterilizable circular flumes designed to allow single-species cyanobacterial growth under adjustable fluid-flow conditions and protected from contamination.

  16. Astronaut Thomas Mattingly performs EVA during Apollo 16 transearth coast

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Astronaut Thomas K. Mattingly II, command module pilot of the Apollo 16 lunar landing mission, performs extravehicular activity (EVA) during the Apollo 16 transearth coast. mattingly is assisted by Astronaut Charles M. Duke Jr., lunar module pilot. Mattingly inspected the SIM bay of the Service Module, and retrieved film from the Mapping and Panoramic cameras. Mattingly is wearing the helmet of Astronaut John W. Young, commander. The helmet's lunar extravehicular visor assembly helped protect Mattingly's eyes frmo the bright sun. This view is a frame from motion picture film exposed by a 16mm Maurer camera.

  17. Transient analysis of distribution class Adaptive Var Compensators: Simulation and field test results

    SciTech Connect

    Kagalwala, R.A.; Venkata, S.S.; El-Sharkawi, M.A.; Butler, N.G.; Van Leuven, A.; Rodriguez, A.P.; Kerszenbaum, I.; Smith, D.

    1995-04-01

    Simulation studies are performed to analyze the transient behavior of the Adaptive Var Compensator (AVC), a power electronic device installed at the distribution level, during its design, installation and field testing stages. The simulation model includes detailed models for power apparatus, power semiconductor devices and low signal level electronics. Hence, by using this model, a wide range of simulation studies which contribute towards the development of the AVC and its effectiveness in the field can all be performed on the same platform. A new power electronics simulator called SABER has proven to be very effective for this study because of its model-independent structure and extensive library that covers various disciplines of engineering. The simulation studies are aimed at gaining a better understanding of the interaction between the AVC and the distribution system. They cover a range of phenomena such as switching transients due to mechanical capacitor bank closing, fast transients due to reverse recovery of the power diodes of the AVC, power system harmonics and voltage flicker problem. This paper also briefly describes the criteria for selection of the simulation tool and the models developed.

  18. Flight Test of an Adaptive Configuration Optimization System for Transport Aircraft

    NASA Technical Reports Server (NTRS)

    Gilyard, Glenn B.; Georgie, Jennifer; Barnicki, Joseph S.

    1999-01-01

    A NASA Dryden Flight Research Center program explores the practical application of real-time adaptive configuration optimization for enhanced transport performance on an L-1011 aircraft. This approach is based on calculation of incremental drag from forced-response, symmetric, outboard aileron maneuvers. In real-time operation, the symmetric outboard aileron deflection is directly optimized, and the horizontal stabilator and angle of attack are indirectly optimized. A flight experiment has been conducted from an onboard research engineering test station, and flight research results are presented herein. The optimization system has demonstrated the capability of determining the minimum drag configuration of the aircraft in real time. The drag-minimization algorithm is capable of identifying drag to approximately a one-drag-count level. Optimizing the symmetric outboard aileron position realizes a drag reduction of 2-3 drag counts (approximately 1 percent). Algorithm analysis of maneuvers indicate that two-sided raised-cosine maneuvers improve definition of the symmetric outboard aileron drag effect, thereby improving analysis results and consistency. Ramp maneuvers provide a more even distribution of data collection as a function of excitation deflection than raised-cosine maneuvers provide. A commercial operational system would require airdata calculations and normal output of current inertial navigation systems; engine pressure ratio measurements would be optional.

  19. Preliminary tests of a low-cost solar infrared adaptive optics system

    NASA Astrophysics Data System (ADS)

    Ammons, S. M.; Keller, C. U.

    2002-05-01

    Images produced by the National Solar Observatory's McMath-Pierce telescope on Kitt Peak, the largest solar telescope in the world, have been at the mercy of atmospheric turbulence for decades. Work is currently underway to install a low-cost adaptive optics system with the goal of correction in the infrared for a total hardware cost of \\$25k. As a preliminary step, a slow AO system was constructed in the lab to demonstrate the feasibility of the low-cost approach. The design is a simple feedback loop that reads the wavefront shape with a Hartmann wavefront sensor and makes corrections through a micromachined membrane deformable mirror. A computer calculates the voltages to apply to the 37-actuator mirror based on the wavefront information. The system operates at 1 Hz and is able to correct a distorted laser wavefront within several cycles. This test paves the way to deploy a faster version of this system that runs at 500 Hz. Funded by NSF.

  20. DRAGON, the Durham real-time, tomographic adaptive optics test bench: progress and results

    NASA Astrophysics Data System (ADS)

    Reeves, Andrew P.; Myers, Richard M.; Morris, Timothy J.; Basden, Alastair G.; Bharmal, Nazim A.; Rolt, Stephen; Bramall, David G.; Dipper, Nigel A.; Younger, Edward J.

    2014-08-01

    DRAGON is a real-time, tomographic Adaptive Optics test bench currently under development at Durham University. Optical and mechanical design work for DRAGON is now complete, and the system is close to becoming fully operational. DRAGON emulates current 4.2 m and 8 m telescopes, and can also be used to investigate ELT scale issues. The full system features 4 Laser Guide Star (LGS) Wavefront Sensors (WFS), 3 Natural Guide Star (NGS) WFSs and one Truth Sensor, all of which are 31 × 31 sub-aperture Shack-Hartmann WFS. Two Deformable Mirrors (DMs), a Boston MEMS Kilo DM and a Xinetics 97 actuator DM, correct for turbulence induced aberrations and these can be configured to be either open or closed loop of the WFS. A novel method of LGS emulation is implemented which includes the effects of uplink turbulence and elongation in real-time. The atmosphere is emulated by 4 rotating phase screens which can be translated in real-time to replicate altitude evolution of turbulent layers. DRAGON will be used to extensively study tomographic AO algorithms, such as those required for Multi-Object AO. As DRAGON has been designed to be compatible with CANARY, the MOAO demonstrator, results can be compared to those from the CANARY MOAO demonstrator on the 4.2m William Herschel Telescope. We present here an overview of the current status of DRAGON and some early results, including investigations into the validity of the LGS emulation method.

  1. Participation in Decision Making as a Property of Complex Adaptive Systems: Developing and Testing a Measure

    PubMed Central

    Anderson, Ruth A.; Hsieh, Pi-Ching; Su, Hui Fang; Landerman, Lawrence R.; McDaniel, Reuben R.

    2013-01-01

    Objectives. To (1) describe participation in decision-making as a systems-level property of complex adaptive systems and (2) present empirical evidence of reliability and validity of a corresponding measure. Method. Study 1 was a mail survey of a single respondent (administrators or directors of nursing) in each of 197 nursing homes. Study 2 was a field study using random, proportionally stratified sampling procedure that included 195 organizations with 3,968 respondents. Analysis. In Study 1, we analyzed the data to reduce the number of scale items and establish initial reliability and validity. In Study 2, we strengthened the psychometric test using a large sample. Results. Results demonstrated validity and reliability of the participation in decision-making instrument (PDMI) while measuring participation of workers in two distinct job categories (RNs and CNAs). We established reliability at the organizational level aggregated items scores. We established validity of the multidimensional properties using convergent and discriminant validity and confirmatory factor analysis. Conclusions. Participation in decision making, when modeled as a systems-level property of organization, has multiple dimensions and is more complex than is being traditionally measured. Managers can use this model to form decision teams that maximize the depth and breadth of expertise needed and to foster connection among them. PMID:24349771

  2. A Test for Pre-Adapted Phenotypic Plasticity in the Invasive Tree Acer negundo L.

    PubMed Central

    Lamarque, Laurent J.; Porté, Annabel J.; Eymeric, Camille; Lasnier, Jean-Baptiste; Lortie, Christopher J.; Delzon, Sylvain

    2013-01-01

    Phenotypic plasticity is a key mechanism associated with the spread of exotic plants and previous studies have found that invasive species are generally more plastic than co-occurring species. Comparatively, the evolution of phenotypic plasticity in plant invasion has received less attention, and in particular, the genetic basis of plasticity is largely unexamined. Native from North America, Acer negundo L. is aggressively impacting the riparian forests of southern and eastern Europe thanks to higher plasticity relative to co-occurring native species. We therefore tested here whether invasive populations have evolved increased plasticity since introduction. The performance of 1152 seedlings from 8 native and 8 invasive populations was compared in response to nutrient availability. Irrespective of nutrients, invasive populations had higher growth and greater allocation to above-ground biomass relative to their native conspecifics. More importantly, invasive genotypes did not show increased plasticity in any of the 20 traits examined. This result suggests that the high magnitude of plasticity to nutrient variation of invasive seedlings might be pre-adapted in the native range. Invasiveness of A. negundo could be explained by higher mean values of traits due to genetic differentiation rather than by evolution of increased plasticity. PMID:24040212

  3. The Accuracy of Computerized Adaptive Testing in Heterogeneous Populations: A Mixture Item-Response Theory Analysis

    PubMed Central

    Kopec, Jacek A.; Wu, Amery D.; Zumbo, Bruno D.

    2016-01-01

    Background Computerized adaptive testing (CAT) utilizes latent variable measurement model parameters that are typically assumed to be equivalently applicable to all people. Biased latent variable scores may be obtained in samples that are heterogeneous with respect to a specified measurement model. We examined the implications of sample heterogeneity with respect to CAT-predicted patient-reported outcomes (PRO) scores for the measurement of pain. Methods A latent variable mixture modeling (LVMM) analysis was conducted using data collected from a heterogeneous sample of people in British Columbia, Canada, who were administered the 36 pain domain items of the CAT-5D-QOL. The fitted LVMM was then used to produce data for a simulation analysis. We evaluated bias by comparing the referent PRO scores of the LVMM with PRO scores predicted by a “conventional” CAT (ignoring heterogeneity) and a LVMM-based “mixture” CAT (accommodating heterogeneity). Results The LVMM analysis indicated support for three latent classes with class proportions of 0.25, 0.30 and 0.45, which suggests that the sample was heterogeneous. The simulation analyses revealed differences between the referent PRO scores and the PRO scores produced by the “conventional” CAT. The “mixture” CAT produced PRO scores that were nearly equivalent to the referent scores. Conclusion Bias in PRO scores based on latent variable models may result when population heterogeneity is ignored. Improved accuracy could be obtained by using CATs that are parameterized using LVMM. PMID:26930348

  4. Biodiversity within hot spring microbial mat communities: molecular monitoring of enrichment cultures

    NASA Technical Reports Server (NTRS)

    Ward, D. M.; Santegoeds, C. M.; Nold, S. C.; Ramsing, N. B.; Ferris, M. J.; Bateson, M. M.

    1997-01-01

    We have begun to examine the basis for incongruence between hot spring microbial mat populations detected by cultivation or by 16S rRNA methods. We used denaturing gradient gel electrophoresis (DGGE) to monitor enrichments and isolates plated therefrom. At near extincting inoculum dilutions we observed Chloroflexus-like and cyanobacterial populations whose 16S rRNA sequences have been detected in the 'New Pit' Spring Chloroflexus mat and the Octopus Spring cyanobacterial mat. Cyanobacterial populations enriched from 44 to 54 degrees C and 56 to 63 degrees C samples at near habitat temperatures were similar to those previously detected in mat samples of comparable temperatures. However, a lower temperature enrichment from the higher temperature sample selected for the populations found in the lower temperature sample. Three Thermus populations detected by both DGGE and isolation exemplify even more how enrichment may bias our view of community structure. The most abundant population was adapted to the habitat temperature (50 degrees C), while populations adapted to 65 degrees C and 70 degrees C were 10(2)- and 10(4)-fold less abundant, respectively. However, enrichment at 70 degrees C favored the least abundant strain. Inoculum dilution and incubation at the habitat temperature favored the more numerically relevant populations. We enriched many other aerobic chemoorganotrophic populations at various inoculum dilutions and substrate concentrations, most of whose 16S rRNA sequences have not been detected in mats. A common feature of numerically relevant cyanobacterial, Chloroflexus-like and aerobic chemorganotrophic populations, is that they grow poorly and resist cultivation on solidified medium, suggesting plating bias, and that the medium composition and incubation conditions may not reflect the natural microenvironments these populations inhabit.

  5. Benchmark tests and spin adaptation for the particle-particle random phase approximation.

    PubMed

    Yang, Yang; van Aggelen, Helen; Steinmann, Stephan N; Peng, Degao; Yang, Weitao

    2013-11-07

    The particle-particle random phase approximation (pp-RPA) provides an approximation to the correlation energy in density functional theory via the adiabatic connection [H. van Aggelen, Y. Yang, and W. Yang, Phys. Rev. A 88, 030501 (2013)]. It has virtually no delocalization error nor static correlation error for single-bond systems. However, with its formal O(N(6)) scaling, the pp-RPA is computationally expensive. In this paper, we implement a spin-separated and spin-adapted pp-RPA algorithm, which reduces the computational cost by a substantial factor. We then perform benchmark tests on the G2/97 enthalpies of formation database, DBH24 reaction barrier database, and four test sets for non-bonded interactions (HB6/04, CT7/04, DI6/04, and WI9/04). For the G2/97 database, the pp-RPA gives a significantly smaller mean absolute error (8.3 kcal/mol) than the direct particle-hole RPA (ph-RPA) (22.7 kcal/mol). Furthermore, the error in the pp-RPA is nearly constant with the number of atoms in a molecule, while the error in the ph-RPA increases. For chemical reactions involving typical organic closed-shell molecules, pp- and ph-RPA both give accurate reaction energies. Similarly, both RPAs perform well for reaction barriers and nonbonded interactions. These results suggest that the pp-RPA gives reliable energies in chemical applications. The adiabatic connection formalism based on pairing matrix fluctuation is therefore expected to lead to widely applicable and accurate density functionals.

  6. A Web-Based Computerized Adaptive Testing (CAT) to Assess Patient Perception in Hospitalization

    PubMed Central

    Chien, Tsair-Wei; Wang, Wen-Chung; Huang, Sheng-Yun; Lai, Wen-Pin

    2011-01-01

    Background Many hospitals have adopted mobile nursing carts that can be easily rolled up to a patient’s bedside to access charts and help nurses perform their rounds. However, few papers have reported data regarding the use of wireless computers on wheels (COW) at patients’ bedsides to collect questionnaire-based information of their perception of hospitalization on discharge from the hospital. Objective The purpose of this study was to evaluate the relative efficiency of computerized adaptive testing (CAT) and the precision of CAT-based measures of perceptions of hospitalized patients, as compared with those of nonadaptive testing (NAT). An Excel module of our CAT multicategory assessment is provided as an example. Method A total of 200 patients who were discharged from the hospital responded to the CAT-based 18-item inpatient perception questionnaire on COW. The numbers of question administrated were recorded and the responses were calibrated using the Rasch model. They were compared with those from NAT to show the advantage of CAT over NAT. Results Patient measures derived from CAT and NAT were highly correlated (r = 0.98) and their measurement precisions were not statistically different (P = .14). CAT required fewer questions than NAT (an efficiency gain of 42%), suggesting a reduced burden for patients. There were no significant differences between groups in terms of gender and other demographic characteristics. Conclusions CAT-based administration of surveys of patient perception substantially reduced patient burden without compromising the precision of measuring patients’ perceptions of hospitalization. The Excel module of animation-CAT on the wireless COW that we developed is recommended for use in hospitals. PMID:21844001

  7. Effect of salinity changes on the bacterial diversity, photosynthesis and oxygen consumption of cyanobacterial mats from an intertidal flat of the Arabian Gulf.

    PubMed

    Abed, Raeid M M; Kohls, Katharina; de Beer, Dirk

    2007-06-01

    The effects of salinity fluctuation on bacterial diversity, rates of gross photosynthesis (GP) and oxygen consumption in the light (OCL) and in the dark (OCD) were investigated in three submerged cyanobacterial mats from a transect on an intertidal flat. The transect ran 1 km inland from the low water mark along an increasingly extreme habitat with respect to salinity. The response of GP, OCL and OCD in each sample to various salinities (65 per thousand, 100 per thousand, 150 per thousand and 200 per thousand) were compared. The obtained sequences and the number of unique operational taxonomic units showed clear differences in the mats' bacterial composition. While cyanobacteria decreased from the lower to the upper tidal mat, other bacterial groups such as Chloroflexus and Cytophaga/Flavobacteria/Bacteriodetes showed an opposite pattern with the highest dominance in the middle and upper tidal mats respectively. Gross photosynthesis and OCL at the ambient salinities of the mats decreased from the lower to the upper tidal zone. All mats, regardless of their tidal location, exhibited a decrease in areal GP, OCL and OCD rates at salinities > 100 per thousand. The extent of inhibition of these processes at higher salinities suggests an increase in salt adaptation of the mats microorganisms with distance from the low water line. We conclude that the resilience of microbial mats towards different salinity regimes on intertidal flats is accompanied by adjustment of the diversity and function of their microbial communities.

  8. Methodological and Theoretical Issues in the Adaptation of Sign Language Tests: An Example from the Adaptation of a Test to German Sign Language

    ERIC Educational Resources Information Center

    Haug, Tobias

    2012-01-01

    Despite the current need for reliable and valid test instruments in different countries in order to monitor the sign language acquisition of deaf children, very few tests are commercially available that offer strong evidence for their psychometric properties. This mirrors the current state of affairs for many sign languages, where very little…

  9. Fabrication and Evaluation of Nanostructured Herbal Oil/Hydroxypropyl-β-Cyclodextrin/Polyvinylpyrrolidone Mats for Denture Stomatitis Prevention and Treatment.

    PubMed

    Tonglairoum, Prasopchai; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Kaomongkolgit, Ruchadaporn; Opanasopit, Praneet

    2016-12-01

    This work aims to develop the herbal oil-incorporated nanostructure mats with antifungal activity for the prevention and treatment of Candida-associated denture stomatitis. The nanofiber mats loaded with betel oil or clove oil were fabricated via electrospinning process. The morphologies and physicochemical properties of the herbal oil loaded nanofiber mats were examined using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and mechanical testing. The release characteristic, antifungal activity, and cytotoxicity were also investigated. The SEM images confirmed the homogeneous and smooth nanoscale fibers. The addition of the herbal oil into the nanofiber mats reduced the fiber diameters. The DSC and FT-IR results confirmed the presence of the oil in the nanofiber mats. The herbal oils can be released from the mats in a very fast manner and inhibit the growth of candida cells within only few minutes after contact. These nanofiber mats may be beneficial for the prevention and treatment of denture stomatitis.

  10. Design of an Adaptive Power Regulation Mechanism and a Nozzle for a Hydroelectric Power Plant Turbine Test Rig

    NASA Astrophysics Data System (ADS)

    Mert, Burak; Aytac, Zeynep; Tascioglu, Yigit; Celebioglu, Kutay; Aradag, Selin; ETU Hydro Research Center Team

    2014-11-01

    This study deals with the design of a power regulation mechanism for a Hydroelectric Power Plant (HEPP) model turbine test system which is designed to test Francis type hydroturbines up to 2 MW power with varying head and flow(discharge) values. Unlike the tailor made regulation mechanisms of full-sized, functional HEPPs; the design for the test system must be easily adapted to various turbines that are to be tested. In order to achieve this adaptability, a dynamic simulation model is constructed in MATLAB/Simulink SimMechanics. This model acquires geometric data and hydraulic loading data of the regulation system from Autodesk Inventor CAD models and Computational Fluid Dynamics (CFD) analysis respectively. The dynamic model is explained and case studies of two different HEPPs are performed for validation. CFD aided design of the turbine guide vanes, which is used as input for the dynamic model, is also presented. This research is financially supported by Turkish Ministry of Development.

  11. Effectiveness of Item Response Theory (IRT) Proficiency Estimation Methods under Adaptive Multistage Testing. Research Report. ETS RR-15-11

    ERIC Educational Resources Information Center

    Kim, Sooyeon; Moses, Tim; Yoo, Hanwook Henry

    2015-01-01

    The purpose of this inquiry was to investigate the effectiveness of item response theory (IRT) proficiency estimators in terms of estimation bias and error under multistage testing (MST). We chose a 2-stage MST design in which 1 adaptation to the examinees' ability levels takes place. It includes 4 modules (1 at Stage 1, 3 at Stage 2) and 3 paths…

  12. Improving Cognitive Diagnostic Computerized Adaptive Testing by Balancing Attribute Coverage: The Modified Maximum Global Discrimination Index Method

    ERIC Educational Resources Information Center

    Cheng, Ying

    2010-01-01

    This article proposes a new item selection method, namely, the modified maximum global discrimination index (MMGDI) method, for cognitive diagnostic computerized adaptive testing (CD-CAT). The new method captures two aspects of the appeal of an item: (a) the amount of contribution it can make toward adequate coverage of every attribute and (b) the…

  13. Translation, Adaptation and Invariance Testing of the Teaching Perspectives Inventory: Comparing Faculty of Malaysia and the United States

    ERIC Educational Resources Information Center

    Misieng, Jecky

    2013-01-01

    As a result of growing attention in cross-cultural research, existing measurement instruments developed in one language are being translated and adapted for use in other languages and cultural contexts. Producing invariant measurement instruments that assess educational and psychological constructs provide a way of testing the cross-cultural…

  14. Computerized Adaptive Testing Using the Partial Credit Model: Effects of Item Pool Characteristics and Different Stopping Rules.

    ERIC Educational Resources Information Center

    Dodd, Barbara G.; And Others

    1993-01-01

    Effects of the following variables on performance of computerized adaptive testing (CAT) procedures for the partial credit model (PCM) were studied: (1) stopping rule for terminating CAT; (2) item pool size; and (3) distribution of item difficulties. Implications of findings for CAT systems based on the PCM are discussed. (SLD)

  15. Comparison between Dichotomous and Polytomous Scoring of Innovative Items in a Large-Scale Computerized Adaptive Test

    ERIC Educational Resources Information Center

    Jiao, Hong; Liu, Junhui; Haynie, Kathleen; Woo, Ada; Gorham, Jerry

    2012-01-01

    This study explored the impact of partial credit scoring of one type of innovative items (multiple-response items) in a computerized adaptive version of a large-scale licensure pretest and operational test settings. The impacts of partial credit scoring on the estimation of the ability parameters and classification decisions in operational test…

  16. "Computerized Adaptive Testing: Theory and Practice." Wim J. van der Linden and Cees A. W. Glas, Eds. [book review].

    ERIC Educational Resources Information Center

    Reise, Steven P.

    2001-01-01

    This book contains a series of research articles about computerized adaptive testing (CAT) written for advanced psychometricians. The book is divided into sections on: (1) item selection and examinee scoring in CAT; (2) examples of CAT applications; (3) item banks; (4) determining model fit; and (5) using testlets in CAT. (SLD)

  17. Teaching the Fluctuation Test "In Silico" by Using Mutate: A Program to Distinguish between the Adaptive and Spontaneous Mutation Hypotheses

    ERIC Educational Resources Information Center

    Carvajal-Rodriguez, Antonio

    2012-01-01

    Mutate is a program developed for teaching purposes to impart a virtual laboratory class for undergraduate students of Genetics in Biology. The program emulates the so-called fluctuation test whose aim is to distinguish between spontaneous and adaptive mutation hypotheses in bacteria. The plan is to train students in certain key multidisciplinary…

  18. Cross-Cultural Adaptation and Validation of the Jebsen-Taylor Hand Function Test in an Italian Population

    PubMed Central

    Culicchia, Greta; Nobilia, Marta; Asturi, Marilyn; Santilli, Valter; Paoloni, Marco; De Santis, Rita

    2016-01-01

    Objective. This paper describes the Italian translation and adaptation to the Italian culture of the original version of the Jebsen-Taylor hand function test and conveys the procedure for testing its validity and reliability. Design. The cultural adaptation process and validation were based on data from a group of people with no clinical evidence of disease or impairment of the upper limbs. The process required a forward and reverse translation in its original language. The scale obtained was reviewed by 8 experts in the field of psychometrics dealing with statistical methods that are useful for the behavioral and social sciences. The Italian adapted version of the JTHFT was then produced and validated. Participants. The test was submitted to 320 people with no clinical evidence of disease in order to test its acceptability and consistency. Results. The total time required to perform each subtest was 80.16 ± 43.13 seconds for the nondominant hand (NDH) and 49.97 ± 27.28 seconds for the dominant hand (DH). The internal consistency (assessed with Pearson's r) and the reliability or the construct validity (assessed with Cronbach's alpha) are significative. Conclusions. This is the first study reporting the result of the translation, cultural adaptation, and validation protocols of the JTHFT in Italian. It provides a new tool for Italian professionals to measure the functionality of the hand in participants with various upper limb pathologies. PMID:27504203

  19. Development of a Postacute Hospital Item Bank for the New Pediatric Evaluation of Disability Inventory-Computer Adaptive Test

    ERIC Educational Resources Information Center

    Dumas, Helene M.

    2010-01-01

    The PEDI-CAT is a new computer adaptive test (CAT) version of the Pediatric Evaluation of Disability Inventory (PEDI). Additional PEDI-CAT items specific to postacute pediatric hospital care were recently developed using expert reviews and cognitive interviewing techniques. Expert reviews established face and construct validity, providing positive…

  20. Adaptation and Validation of the Tower of London Test of Planning and Problem Solving in People with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Masson, J. D.; Dagnan, D.; Evans, J.

    2010-01-01

    Background: There is a need for validated, standardised tools for the assessment of executive functions in adults with intellectual disabilities (ID). This study examines the validity of a test of planning and problem solving (Tower of London) with adults with ID. Method: Participants completed an adapted version of the Tower of London (ToL) while…

  1. Testing the Adaptation to Poverty-Related Stress Model: Predicting Psychopathology Symptoms in Families Facing Economic Hardship

    ERIC Educational Resources Information Center

    Wadsworth, Martha E.; Raviv, Tali; Santiago, Catherine DeCarlo; Etter, Erica M.

    2011-01-01

    This study tested the Adaptation to Poverty-related Stress Model and its proposed relations between poverty-related stress, effortful and involuntary stress responses, and symptoms of psychopathology in an ethnically diverse sample of low-income children and their parents. Prospective Hierarchical Linear Modeling analyses conducted with 98…

  2. Effect of Rasch Calibration on Ability and DIF Estimation in Computer-Adaptive Tests. Research Report RR-94-32.

    ERIC Educational Resources Information Center

    Zwick, Rebecca; And Others

    A previous simulation study of methods for assessing item functioning (DIF) in computer-adaptive tests (CATs) showed that modified versions of the Mantel-Haenszel and standardization methods work well with CAT data. In that study, data were generated using the three-parameter logistic (3PL) model, and this same model was assumed in obtaining item…

  3. Application of an Empirical Bayes Enhancement of Mantel-Haenszel Differential Item Functioning Analysis to a Computerized Adaptive Test.

    ERIC Educational Resources Information Center

    Zwick, Rebecca; Thayer, Dorothy T.

    2002-01-01

    Used a simulation to investigate the applicability to computerized adaptive test data of a differential item functioning (DIF) analysis method. Results show the performance of this empirical Bayes enhancement of the Mantel Haenszel DIF analysis method to be quite promising. (SLD)

  4. Content Range and Precision of a Computer Adaptive Test of Upper Extremity Function for Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Montpetit, Kathleen; Haley, Stephen; Bilodeau, Nathalie; Ni, Pengsheng; Tian, Feng; Gorton, George, III; Mulcahey, M. J.

    2011-01-01

    This article reports on the content range and measurement precision of an upper extremity (UE) computer adaptive testing (CAT) platform of physical function in children with cerebral palsy. Upper extremity items representing skills of all abilities were administered to 305 parents. These responses were compared with two traditional standardized…

  5. Construct Validity and Measurement Invariance of Computerized Adaptive Testing: Application to Measures of Academic Progress (MAP) Using Confirmatory Factor Analysis

    ERIC Educational Resources Information Center

    Wang, Shudong; McCall, Marty; Jiao, Hong; Harris, Gregg

    2012-01-01

    The purposes of this study are twofold. First, to investigate the construct or factorial structure of a set of Reading and Mathematics computerized adaptive tests (CAT), "Measures of Academic Progress" (MAP), given in different states at different grades and academic terms. The second purpose is to investigate the invariance of test…

  6. Some Features of the Sampling Distribution of the Ability Estimate in Computerized Adaptive Testing According to Two Stopping Rules.

    ERIC Educational Resources Information Center

    Blais, Jean-Guy; Raiche, Gilles

    This paper examines some characteristics of the statistics associated with the sampling distribution of the proficiency level estimate when the Rasch model is used. These characteristics allow the judgment of the meaning to be given to the proficiency level estimate obtained in adaptive testing, and as a consequence, they can illustrate the…

  7. Development of a Protocol to Test Proprioceptive Utilization as a Predictor for Sensorimotor Adaptability

    NASA Technical Reports Server (NTRS)

    Goel, R.; De Dios, Y. E.; Gadd, N. E.; Caldwell, E. E.; Peters, B. T.; Bloomberg, J. J.; Oddsson, L. I. E.; Mulavara, A. P.

    2016-01-01

    Astronauts returning from space flight show significant inter-subject variations in their abilities to readapt to a gravitational environment because of their innate sensory weighting. The ability to predict the manner and degree to which each individual astronaut will be affected would improve the effectiveness of countermeasure training programs designed to enhance sensorimotor adaptability. We hypothesize participant's ability to utilize individual sensory information (vision, proprioception and vestibular) influences adaptation in sensorimotor performance after space flight. The goal of this study is to develop a reliable protocol to test proprioceptive utilization in a functional postural control task. Subjects "stand" in a supine position while strapped to a backpack frame holding a friction-free device using air-bearings that allow the subject to move freely in the frontal plane, similar to when in upright standing. The frame is attached to a pneumatic cylinder, which can provide different levels of a gravity-like force that the subject must balance against to remain "upright". The supine posture with eyes closed ensures reduced vestibular and visual contribution to postural control suggesting somatosensory and/or non-otolith vestibular inputs will provide relevant information for maintaining balance control in this task. This setup is called the gravity bed. Fourteen healthy subjects carried out three trials each with eyes open alternated with eyes closed, "standing" on their dominant leg in the gravity bed environment while loaded with 60 percent of their body weight. Subjects were instructed to: "use your sense of sway about the ankle and pressure changes under the foot to maintain balance." Maximum length of a trial was 45 seconds. A force plate underneath the foot recorded forces and moments during the trial and an inertial measurement unit (IMU) attached on the backpack's frame near the center of mass of the subject recorded upper body postural

  8. Sociolinguistic reflection on neuropsychological assessment: an insight into selected culturally adapted battery of Lebanese Arabic cognitive testing.

    PubMed

    Abou-Mrad, Fadi; Tarabey, Lubna; Zamrini, Edward; Pasquier, Florence; Chelune, Gordon; Fadel, Patricia; Hayek, Maryse

    2015-10-01

    Neuropsychological tests (NPTs) are highly dependent on education, culture differences as well as age and sex. It is therefore essential to take these factors into consideration when translating NPTs to be used in screening for cognitive impairment. Translations into Arabic must respect the principles of linguistic relativity and cultural specificity of the population under study. The objective is to assess feasibility and outcome of translating neuropsychological tests to Arabic. A team of Lebanese professionals selected a battery of screening NPTs. These tests were translated into Arabic and independently back translated by a team of sociolinguists and cultural specialists. The translations were adapted to suit the Lebanese culture. The final NPT translated versions were reached by consensus of an expert panel and tested on a group of independently living community-dwelling elderly. Translated items had to be modified when: (1) terms could not be translated using one word as required by the test; (2) Concepts were foreign to the culture; (3) Translated words carried multiple meanings; (4) Words were rarely used in Lebanon; (5) Sentences did not have an equivalent; and (6) Words had letters pronounced differently by subgroups in Lebanon. Despite all measures to maintain cultural sensitivity in translations, non-linguistic challenges remained. A battery of cognitive screening tests were translated into Arabic and adapted for the Lebanese population. These adaptations allow for a better assessment of cognitive abilities since they reflect the thought patterns of the population. The challenge is to establish local normative data.

  9. Description of the HiMAT Tailored composite structure and laboratory measured vehicle shape under load

    NASA Technical Reports Server (NTRS)

    Monaghan, R. C.

    1981-01-01

    The aeroelastically tailored outer wing and canard of the highly maneuverable aircraft technology (HiMAT) vehicle are closely examined and a general description of the overall structure of the vehicle is provided. Test data in the form of laboratory measured twist under load and predicted twist from the HiMAT NASTRAN structural design program are compared. The results of this comparison indicate that the measured twist is generally less than the NASTRAN predicted twist. These discrepancies in twist predictions are attributed, at least in part, to the inability of current analytical composite materials programs to provide sufficiently accurate properties of matrix dominated laminates for input into structural programs such as NASTRAN.

  10. Superhydrophobic PVDF and PVDF-HFP nanofibrous mats with antibacterial and anti-biofouling properties

    NASA Astrophysics Data System (ADS)

    Spasova, M.; Manolova, N.; Markova, N.; Rashkov, I.

    2016-02-01

    Superhydrophobic nanofibrous materials of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were prepared by one-pot electrospinning technique. The mats were decorated with ZnO nanoparticles with silanized surface and a model drug - 5-chloro-8-hydroxyquinolinol (5Cl8HQ). The obtained hybrid nanofibrous materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle measurements, mechanical and microbiological tests. The results showed that the incorporation of ZnO nanoparticles into PVDF and PVDF-HFP nanofibers increased the hydrophobicity (contact angle 152°), improved the thermal stability and imparted to the nanofibrous materials anti-adhesive and antimicrobial properties. The mats containing the model drug possessed antibacterial activity against Escherichia coli and Staphylococcus aureus. The results suggested that the obtained hybrid mats could find potential biomedical applications requiring antibacterial and anti-biofouling properties.

  11. Experimental evaluation of the anti-attachment effect of microalgal mats on grazing activity of the sea urchin Strongylocentrotus nudus in oscillating flows.

    PubMed

    Kawamata, Shigeru

    2012-05-01

    Algal mats can hinder the adhesion of the tube feet of sea urchins. This leads to the hypothesis that the restriction of sea urchin feeding activity by wave action can potentially be enhanced by the presence of algal mats, which will facilitate the survival of kelp recruits at sites with wave action in urchin barrens. To evaluate the potential anti-attachment effect of algal mats on sea urchins, a laboratory tank experiment was performed on the movement of Strongylocentrotus nudus sea urchins and their grazing on juvenile kelp plants at the center of 30×30 cm flat test substrates with or without a thin-layer microalgal mat at four levels of oscillatory flow (maximum orbital velocity: 10, 20, 30 and 40 cm s(-1)). The grazing loss of kelp slightly increased with increasing velocity up to 30 cm s(-1) in the absence of microalgal mats, while in contrast the loss substantially decreased at 30 cm s(-1) in their presence. Sea urchins were dislodged more frequently at 20 cm s(-1) or higher velocities in the presence of microalgal mats. Mats were frequently abraded by scraping by the adoral spines during urchin movement at high velocities (30 and 40 cm s(-1)) but were subject to no or only slight urchin grazing in most cases. The results indicate that the overall decrease in grazing loss of kelp within the microalgal mats was attributable to the anti-attachment effect on urchins during incursions rather than due to urchins grazing on the mats.

  12. Comparative ergoespirometric adaptations to a treadmill exercise test in untrained show Andalusian and Arabian horses.

    PubMed

    Castejón-Riber, Cristina; Muñoz, Ana; Trigo, Pablo; Riber, Cristina; Santisteban, Rafael; Castejón, Francisco

    2012-03-01

    Significant differences exist in the respiratory adaptation to exercise in different equine breeds. This research describes the ergoespirometric response to exercise of Andalusian (AN) and Arabian (A) horses, both selected according to morphological criteria. Thirteen untrained male horses (6 AN and 7 A) performed a treadmill exercise test (TET) with a slope of 6%, with workloads starting from 5 m/s and increasing 1 m/s every 3 min until the horses were not able to keep the required velocity. Tidal volume (TV), respiratory rate, minute ventilation (VE), oxygen uptake (VO2), carbon dioxide production, peak oxygen uptake (VO2peak), respiratory exchange ratio (RER), exercise time to fatigue (ETF) and respiratory aerobic threshold (RAT) were determined. AN horses presented higher TV and VE, whereas respiratory rate, VO2 and VCO2 were lower at the same velocities. RER was similar between breeds. ETF was longer in A horses (556.7 ± 66.5 in AN vs. 607.1 ± 71.1 s in A) and no significant differences were found in RAT (5.50 ± 0.50 in AN vs. 5.86 ± 1.07 m/s in A). In summary, despite the more intense ventilatory response to exercise at the same velocity, AN horses had lower VO2. The AN horse develops a more intense ventilatory response to fixed velocities than the A horse and it could be interesting to clarify the role of the locomotion characteristics in this response.

  13. Improving Inpatient Surveys: Web-Based Computer Adaptive Testing Accessed via Mobile Phone QR Codes

    PubMed Central

    2016-01-01

    Background The National Health Service (NHS) 70-item inpatient questionnaire surveys inpatients on their perceptions of their hospitalization experience. However, it imposes more burden on the patient than other similar surveys. The literature shows that computerized adaptive testing (CAT) based on item response theory can help shorten the item length of a questionnaire without compromising its precision. Objective Our aim was to investigate whether CAT can be (1) efficient with item reduction and (2) used with quick response (QR) codes scanned by mobile phones. Methods After downloading the 2008 inpatient survey data from the Picker Institute Europe website and analyzing the difficulties of this 70-item questionnaire, we used an author-made Excel program using the Rasch partial credit model to simulate 1000 patients’ true scores followed by a standard normal distribution. The CAT was compared to two other scenarios of answering all items (AAI) and the randomized selection method (RSM), as we investigated item length (efficiency) and measurement accuracy. The author-made Web-based CAT program for gathering patient feedback was effectively accessed from mobile phones by scanning the QR code. Results We found that the CAT can be more efficient for patients answering questions (ie, fewer items to respond to) than either AAI or RSM without compromising its measurement accuracy. A Web-based CAT inpatient survey accessed by scanning a QR code on a mobile phone was viable for gathering inpatient satisfaction responses. Conclusions With advances in technology, patients can now be offered alternatives for providing feedback about hospitalization satisfaction. This Web-based CAT is a possible option in health care settings for reducing the number of survey items, as well as offering an innovative QR code access. PMID:26935793

  14. Cultural Adaptation of the Portuguese Version of the “Sniffin’ Sticks” Smell Test: Reliability, Validity, and Normative Data

    PubMed Central

    Ribeiro, João Carlos; Simões, João; Silva, Filipe; Silva, Eduardo D.; Hummel, Cornelia; Hummel, Thomas; Paiva, António

    2016-01-01

    The cross-cultural adaptation and validation of the Sniffin`Sticks test for the Portuguese population is described. Over 270 people participated in four experiments. In Experiment 1, 67 participants rated the familiarity of presented odors and seven descriptors of the original test were adapted to a Portuguese context. In Experiment 2, the Portuguese version of Sniffin`Sticks test was administered to 203 healthy participants. Older age, male gender and active smoking status were confirmed as confounding factors. The third experiment showed the validity of the Portuguese version of Sniffin`Sticks test in discriminating healthy controls from patients with olfactory dysfunction. In Experiment 4, the test-retest reliability for both the composite score (r71 = 0.86) and the identification test (r71 = 0.62) was established (p<0.001). Normative data for the Portuguese version of Sniffin`Sticks test is provided, showing good validity and reliability and effectively distinguishing patients from healthy controls with high sensitivity and specificity. The Portuguese version of Sniffin`Sticks test identification test is a clinically suitable screening tool in routine outpatient Portuguese settings. PMID:26863023

  15. The role of disease perceptions and results sharing in psychological adaptation after genetic susceptibility testing: the REVEAL Study.

    PubMed

    Ashida, Sato; Koehly, Laura M; Roberts, J Scott; Chen, Clara A; Hiraki, Susan; Green, Robert C

    2010-12-01

    This study evaluates the extent to which psychological adaptation (validated measures of depressive symptoms, anxiety, and test-specific distress) after genetic susceptibility testing is influenced by changes in beliefs about Alzheimer's disease (AD) and sharing of test results with others. Adult children of AD patients (N=269) from a randomized clinical trial involving genetic testing for apolipoprotein E (APOE) provided information before, as well as 6 weeks and 12 months after results disclosure. The levels of adaptation varied highly among participants at 12-month assessment. Participants who learned that they were ε4 negative (lower risk) had a reduction in perceived risk and concern about developing AD compared with those who learned that they were ε4 positive. Those who received results through an extended educational protocol (three in-person visits) had a larger decline in AD concern than those in a condensed protocol (educational brochure and two in-person visits). Increase in AD concern 6 weeks after disclosure was associated with increase in depression scores (b=0.20, P<0.01) and anxiety levels (b=0.20, P<0.01), and higher distress associated with AD genetic testing (b=0.18, P=0.02) 1 year after testing. Increase in perceived risk (b=0.16, P=0.04) was also associated with higher AD genetic testing distress. Sharing the test results with health professionals and friends (but not family) was associated with decrease in depression (b=-0.11, P=0.05) and anxiety levels (b=-0.16, P<0.01), respectively after a year. Enhancing discussion with regard to risks and concerns about AD during pretesting counseling and obtaining support through sharing the results after testing may help facilitate test recipients' long-term psychological adaptation.

  16. Applying Computerized Adaptive Testing to the Four-Dimensional Symptom Questionnaire (4DSQ): A Simulation Study

    PubMed Central

    de Beurs, Derek P; Terluin, Berend; Verhaak, Peter F

    2017-01-01

    Background Efficient screening questionnaires are useful in general practice. Computerized adaptive testing (CAT) is a method to improve the efficiency of questionnaires, as only the items that are particularly informative for a certain responder are dynamically selected. Objective The objective of this study was to test whether CAT could improve the efficiency of the Four-Dimensional Symptom Questionnaire (4DSQ), a frequently used self-report questionnaire designed to assess common psychosocial problems in general practice. Methods A simulation study was conducted using a sample of Dutch patients visiting a general practitioner (GP) with psychological problems (n=379). Responders completed a paper-and-pencil version of the 50-item 4DSQ and a psychometric evaluation was performed to check if the data agreed with item response theory (IRT) assumptions. Next, a CAT simulation was performed for each of the four 4DSQ scales (distress, depression, anxiety, and somatization), based on the given responses as if they had been collected through CAT. The following two stopping rules were applied for the administration of items: (1) stop if measurement precision is below a predefined level, or (2) stop if more than half of the items of the subscale are administered. Results In general, the items of each of the four scales agreed with IRT assumptions. Application of the first stopping rule reduced the length of the questionnaire by 38% (from 50 to 31 items on average). When the second stopping rule was also applied, the total number of items could be reduced by 56% (from 50 to 22 items on average). Conclusions CAT seems useful for improving the efficiency of the 4DSQ by 56% without losing a considerable amount of measurement precision. The CAT version of the 4DSQ may be useful as part of an online assessment to investigate the severity of mental health problems of patients visiting a GP. This simulation study is the first step needed for the development a CAT version of the 4

  17. Carrageenan analysis. Part 1: Characterisation of the carrageenan test material and stability in swine-adapted infant formula.

    PubMed

    Blakemore, William R; Davis, Steven R; Hroncich, Maggie M; Vurma, Mustafa

    2014-01-01

    A method was developed and validated in support of a 28-day feeding study of swine-adapted infant formula stabilised with carrageenan administered to neonatal piglets. Carrageenan concentrations in the test formulations were 0, 300, 1000 and 2250 mg kg(-1) formula. Extraction of carrageenan from swine-adapted infant formula was achieved by breaking carrageenan-protein cross-linkages using saturated sodium chloride, followed by separation of the non-gelling carrageenan fraction via centrifugation. The extraction of carrageenan from formula was successful with respect to consistent recovery of the non-gelling carrageenan fraction from both test and control formula samples. Molecular weight analysis (Mw) of the recovered carrageenan fractions from the test and control formula samples confirmed that the carrageenan used to manufacture the formula was not degraded during the infant formula production process and subsequent storage for 4 months covering the 28-day piglet dietary feeding study. Carrageenan has excellent stability in infant formulations.

  18. Reducing the width of confidence intervals for the difference between two population means by inverting adaptive tests.

    PubMed

    O'Gorman, Thomas W

    2016-08-08

    In the last decade, it has been shown that an adaptive testing method could be used, along with the Robbins-Monro search procedure, to obtain confidence intervals that are often narrower than traditional confidence intervals. However, these confidence interval limits require a great deal of computation and some familiarity with stochastic search methods. We propose a method for estimating the limits of confidence intervals that uses only a few tests of significance. We compare these limits to those obtained by a lengthy Robbins-Monro stochastic search and find that the proposed method is nearly as accurate as the Robbins-Monro search. Adaptive confidence intervals that are produced by the proposed method are often narrower than traditional confidence intervals when the distributions are long-tailed, skewed, or bimodal. Moreover, the proposed method of estimating confidence interval limits is easy to understand, because it is based solely on the p-values from a few tests of significance.

  19. Integrating non-animal test information into an adaptive testing strategy - skin sensitization proof of concept case.

    PubMed

    Jaworska, Joanna; Harol, Artsiom; Kern, Petra S; Gerberick, G Frank

    2011-01-01

    There is an urgent need to develop data integration and testing strategy frameworks allowing interpretation of results from animal alternative test batteries. To this end, we developed a Bayesian Network Integrated Testing Strategy (BN ITS) with the goal to estimate skin sensitization hazard as a test case of previously developed concepts (Jaworska et al., 2010). The BN ITS combines in silico, in chemico, and in vitro data related to skin penetration, peptide reactivity, and dendritic cell activation, and guides testing strategy by Value of Information (VoI). The approach offers novel insights into testing strategies: there is no one best testing strategy, but the optimal sequence of tests depends on information at hand, and is chemical-specific. Thus, a single generic set of tests as a replacement strategy is unlikely to be most effective. BN ITS offers the possibility of evaluating the impact of generating additional data on the target information uncertainty reduction before testing is commenced.

  20. Implementation of an Adaptive Controller System from Concept to Flight Test

    NASA Technical Reports Server (NTRS)

    Larson, Richard R.; Burken, John J.; Butler, Bradley S.; Yokum, Steve

    2009-01-01

    tunable metrics for the FL are (1) window size, (2) drift rate, and (3) persistence counter. Ultimate range limits are also included in case the NN command should drift slowly to a limit value that would cause the FL to be defeated. The FL has proven to work as intended. Both high-g transients and excessive structural loads are controlled with NN hard-over commands. This presentation discusses the FL design features and presents test cases. Simulation runs are included to illustrate the dramatic improvement made to the control of NN hard-over effects. A mission control room display from a flight playback is presented to illustrate the neural net fault display representation. The FL is very adaptable to various requirements and is independent of flight condition. It should be considered as a cost-effective safety monitor to control single-string inputs in general.