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Sample records for test pattern generator

  1. Test pattern generation for ILA sequential circuits

    NASA Technical Reports Server (NTRS)

    Feng, YU; Frenzel, James F.; Maki, Gary K.

    1993-01-01

    An efficient method of generating test patterns for sequential machines implemented using one-dimensional, unilateral, iterative logic arrays (ILA's) of BTS pass transistor networks is presented. Based on a transistor level fault model, the method affords a unique opportunity for real-time fault detection with improved fault coverage. The resulting test sets are shown to be equivalent to those obtained using conventional gate level models, thus eliminating the need for additional test patterns. The proposed method advances the simplicity and ease of the test pattern generation for a special class of sequential circuitry.

  2. Standard Transistor Array (STAR). Volume 2: Test pattern generation

    NASA Technical Reports Server (NTRS)

    Carroll, B. D.

    1979-01-01

    Testing of large scale integrated logic circuits is considered from the point-of-view of automatic test pattern generation. A logic simulator based approach for automatic test pattern generation is taken and is described. The logic model and the timing model used in the simulator are also described. Two methods are presented for generating test patterns from the output of the simulator. Recommendations for future study are also presented.

  3. Ring Counter Based ATPG for Low Transition Test Pattern Generation.

    PubMed

    Begam, V M Thoulath; Baulkani, S

    2015-01-01

    In test mode test patterns are applied in random fashion to the circuit under circuit. This increases switching transition between the consecutive test patterns and thereby increases dynamic power dissipation. The proposed ring counter based ATPG reduces vertical switching transitions by inserting test vectors only between the less correlative test patterns. This paper presents the RC-ATPG with an external circuit. The external circuit consists of XOR gates, full adders, and multiplexers. First the total number of transitions between the consecutive test patterns is determined. If it is more, then the external circuit generates and inserts test vectors in between the two test patterns. Test vector insertion increases the correlation between the test patterns and reduces dynamic power dissipation. The results prove that the test patterns generated by the proposed ATPG have fewer transitions than the conventional ATPG. Experimental results based on ISCAS'85 and ISCAS'89 benchmark circuits show 38.5% reduction in the average power and 50% reduction in the peak power attained during testing with a small size decoding logic. PMID:26075295

  4. Pattern Generator for Bench Test of Digital Boards

    NASA Technical Reports Server (NTRS)

    Berkun, Andrew C.; Chu, Anhua J.

    2012-01-01

    All efforts to develop electronic equipment reach a stage where they need a board test station for each board. The SMAP digital system consists of three board types that interact with each other using interfaces with critical timing. Each board needs to be tested individually before combining into the integrated digital electronics system. Each board needs critical timing signals from the others to be able to operate. A bench test system was developed to support test of each board. The test system produces all the outputs of the control and timing unit, and is delivered much earlier than the timing unit. Timing signals are treated as data. A large file is generated containing the state of every timing signal at any instant. This file is streamed out to an IO card, which is wired directly to the device-under-test (DUT) input pins. This provides a flexible test environment that can be adapted to any of the boards required to test in a standalone configuration. The problem of generating the critical timing signals is then transferred from a hardware problem to a software problem where it is more easily dealt with.

  5. DALG: A program for test pattern generation in combinational logical circuits

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A user's manual for a computer program DALG which generates test patterns for detecting faults in combinational logic circuits containing up to 200 logical gates is presented. The gates may be of logical types AND, OR, NAND, NOR, NOT, or Exclusive OR is presented. The faults may be any one gate or input struck at a fixed value (0 or 1). In addition to test pattern generation DALG will also determine whether or not the given test pattern will detect given faults in a circuit. Sample problems are given along with input data sheets and printed output to illustrate the capabilities of the program.

  6. Walmsley CVC Patterns Test.

    ERIC Educational Resources Information Center

    Walmsley, Sean A.

    Designed to provide a criterion referenced measurement of CVC (consonant vowel consonant) word patterns, this test consists of six subtests of 152 items prepared as slides for projection. Items are to be presented to the subjects on two separate occasions. (This document is one of those reviewed in The Research Instruments Project (TRIP) monograph…

  7. Invertebrate central pattern generator circuits

    PubMed Central

    Selverston, Allen I.

    2010-01-01

    There are now a reasonable number of invertebrate central pattern generator (CPG) circuits described in sufficient detail that a mechanistic explanation of how they work is possible. These small circuits represent the best-understood neural circuits with which to investigate how cell-to-cell synaptic connections and individual channel conductances combine to generate rhythmic and patterned output. In this review, some of the main lessons that have appeared from this analysis are discussed and concrete examples of circuits ranging from single phase to multiple phase patterns are described. While it is clear that the cellular components of any CPG are basically the same, the topology of the circuits have evolved independently to meet the particular motor requirements of each individual organism and only a few general principles of circuit operation have emerged. The principal usefulness of small systems in relation to the brain is to demonstrate in detail how cellular infrastructure can be used to generate rhythmicity and form specialized patterns in a way that may suggest how similar processes might occur in more complex systems. But some of the problems and challenges associated with applying data from invertebrate preparations to the brain are also discussed. Finally, I discuss why it is useful to have well-defined circuits with which to examine various computational models that can be validated experimentally and possibly applied to brain circuits when the details of such circuits become available. PMID:20603355

  8. Creative Test Generators

    ERIC Educational Resources Information Center

    Vickers, F. D.

    1973-01-01

    A brief description of a test generating program which generates questions concerning the Fortran programming language in a random but guided fashion and without resorting to an item bank.'' (Author/AK)

  9. [Thrombin generation test].

    PubMed

    Espitia, O; Fouassier, M

    2015-10-01

    Thrombin is a key enzyme of the coagulation cascade, having both pro- and anticoagulant functions. Global haemostasis assay, the so-called thrombin generation test is appropriate for its assessment. Estimation of an individual's potential to generate thrombin may correlate more closely with a hyper- or hypo-coagulable phenotype, compared to traditional coagulation tests. In patients at risk of venous thrombosis, thrombin generation analysis may be utilized to detect underlying thrombophilia. In patients with documented venous thromboembolism, increased thrombin generation values are seen in those patients at greatest risk for recurrence. In patients with arterial vascular disease, the data are limited. In case of haemophilia thrombin generation assays reflect bleeding severity. It is applicable for monitoring of both conventional haemophilia treatment and inhibitor-bypassing therapy, which is needed when inhibitors develop in patients. Standardization of thrombin generation methods and determination of cut off-values are required before its application in clinical practice. PMID:26028157

  10. Automatic Test-Case Generation

    NASA Astrophysics Data System (ADS)

    Machado, Patrícia; Sampaio, Augusto

    This chapter is an introduction to the theory, techniques, and tool support for automatic test-case generation. We discuss how test models can be generated, for instance, from requirements specifications, and present different criteria and strategies for generating and selecting test cases from these models. The Target tool is presented and used in this the chapter for illustrating test-case generation techniques along with a case study in the domain of mobile-phone applications. Target generates abstract test cases from use-case specifications presented as templates whose contents are described using a controlled natural language.

  11. Silicon central pattern generators for cardiac diseases

    PubMed Central

    Nogaret, Alain; O'Callaghan, Erin L; Lataro, Renata M; Salgado, Helio C; Meliza, C Daniel; Duncan, Edward; Abarbanel, Henry D I; Paton, Julian F R

    2015-01-01

    Cardiac rhythm management devices provide therapies for both arrhythmias and resynchronisation but not heart failure, which affects millions of patients worldwide. This paper reviews recent advances in biophysics and mathematical engineering that provide a novel technological platform for addressing heart disease and enabling beat-to-beat adaptation of cardiac pacing in response to physiological feedback. The technology consists of silicon hardware central pattern generators (hCPGs) that may be trained to emulate accurately the dynamical response of biological central pattern generators (bCPGs). We discuss the limitations of present CPGs and appraise the advantages of analog over digital circuits for application in bioelectronic medicine. To test the system, we have focused on the cardio-respiratory oscillators in the medulla oblongata that modulate heart rate in phase with respiration to induce respiratory sinus arrhythmia (RSA). We describe here a novel, scalable hCPG comprising physiologically realistic (Hodgkin–Huxley type) neurones and synapses. Our hCPG comprises two neurones that antagonise each other to provide rhythmic motor drive to the vagus nerve to slow the heart. We show how recent advances in modelling allow the motor output to adapt to physiological feedback such as respiration. In rats, we report on the restoration of RSA using an hCPG that receives diaphragmatic electromyography input and use it to stimulate the vagus nerve at specific time points of the respiratory cycle to slow the heart rate. We have validated the adaptation of stimulation to alterations in respiratory rate. We demonstrate that the hCPG is tuneable in terms of the depth and timing of the RSA relative to respiratory phase. These pioneering studies will now permit an analysis of the physiological role of RSA as well as its any potential therapeutic use in cardiac disease. PMID:25433077

  12. Precise-Test-Pulse Generator

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis

    1994-01-01

    Precise test pulse with stable duration and amplitude needed for calibration of test equipment. Precise-test-pulse generator provides such waveform and has additional desirable features. Circuit produces single test pulses of stable duration and amplitude. Made of commercially available integrated circuits and discrete components.

  13. A periodic pattern generator for dental diversity

    PubMed Central

    Fraser, Gareth J; Bloomquist, Ryan F; Streelman, J Todd

    2008-01-01

    Background Periodic patterning of iterative structures is a fundamental process during embryonic organization and development. Studies have shown how gene networks are employed to pattern butterfly eyespots, fly bristles and vertebrate epithelial appendages such as teeth, feathers, hair and mammary glands. Despite knowledge of how these features are organized, little is known about how diversity in periodic patterning is generated in nature. We address this problem through the molecular analysis of oral jaw dental diversity in Lake Malawi cichlids, where closely related species exhibit from 1 to 20 rows of teeth, with total teeth counts ranging from around 10 to 700. Results We investigate the expression of conserved gene networks (involving bmp2, bmp4, eda, edar, fgf8, pax9, pitx2, runx2, shh and wnt7b) known to pattern iterative structures and teeth in other vertebrates. We show that spatiotemporal variation in expression pattern reflects adult morphological diversity among three closely related Malawi cichlid species. Combinatorial epithelial expression of pitx2 and shh appears to govern the competence both of initial tooth sites and future tooth rows. Epithelial wnt7b and mesenchymal eda are expressed in the inter-germ and inter-row regions, and likely regulate the spacing of these shh-positive units. Finally, we used chemical knockdown to demonstrate the fundamental role of hedgehog signalling and initial placode formation in the organization of the periodically patterned cichlid dental programme. Conclusion Coordinated patterns of gene expression differ among Malawi species and prefigure the future-ordered distribution of functional teeth of specific size and spacing. This variation in gene expression among species occurs early in the developmental programme for dental patterning. These data show how a complex multi-rowed vertebrate dentition is organized and how developmental tinkering of conserved gene networks during iterative pattern formation can impact upon the evolution of trophic novelty. PMID:18625062

  14. Automatically generating extraction patterns from untagged text

    SciTech Connect

    Riloff, E.

    1996-12-31

    Many corpus-based natural language processing systems rely on text corpora that have been manually annotated with syntactic or semantic tags. In particular, all previous dictionary construction systems for information extraction have used an annotated training corpus or some form of annotated input. We have developed a system called AutoSlog-TS that creates dictionaries of extraction patterns using only untagged text. AutoSlog-TS is based on the AutoSlog system, which generated extraction patterns using annotated text and a set of heuristic rules. By adapting AutoSlog and combining it with statistical techniques, we eliminated its dependency on tagged text. In experiments with the MUC-4 terrorism domain, AutoSlog-TS created a dictionary of extraction patterns that performed comparably to a dictionary created by AutoSlog, using only preclassified texts as input.

  15. Intersecting Circuits Generate Precisely Patterned Retinal Waves

    PubMed Central

    Akrouh, Alejandro; Kerschensteiner, Daniel

    2013-01-01

    SUMMARY The developing retina generates spontaneous glutamatergic (stage III) waves of activity that sequentially recruit neighboring ganglion cells with opposite light responses (ON and OFF RGCs). This activity pattern is thought to help establish parallel ON and OFF pathways in downstream visual areas. The circuits that produce stage III waves and desynchronize ON and OFF RGC firing remain obscure. Using dual patch clamp recordings, we find that ON and OFF RGCs receive sequential excitatory input from ON and OFF cone bipolar cells (CBCs), respectively. This input sequence is generated by crossover circuits, in which ON CBCs control glutamate release from OFF CBCs via diffusely stratified inhibitory amacrine cells. In addition, neighboring ON CBCs communicate directly and indirectly through lateral glutamatergic transmission and gap junctions, both of which are required for wave initiation and propagation. Thus, intersecting lateral excitatory and vertical inhibitory circuits give rise to precisely patterned stage III retinal waves. PMID:23830830

  16. Grout gas generation test plan

    SciTech Connect

    Person, J.C.

    1995-01-04

    Disclosed are detailed procedures for measuring the rate of gas generation by grout made from synthetic tanks wastes or actual tank material. Objective is to measure the rate of gas generation for various gases (H{sub 2}, N{sub 2}O, etc.) produced when grout, prepared using tank waste, is heated at 65 C. Experiments will also be conducted using grout from synthetic tank waste, as practice. Purpose is to provide data for evaluation of safety risks presented by gas generation in the grout vault after making grout with tank waste, as verification/confirmation for gas generation rates for the ANL testing.

  17. Role of inhibition in respiratory pattern generation.

    PubMed

    Janczewski, Wiktor A; Tashima, Alexis; Hsu, Paul; Cui, Yan; Feldman, Jack L

    2013-03-27

    Postsynaptic inhibition is a key element of neural circuits underlying behavior, with 20-50% of all mammalian (nongranule) neurons considered inhibitory. For rhythmic movements in mammals, e.g., walking, swimming, suckling, chewing, and breathing, inhibition is often hypothesized to play an essential rhythmogenic role. Here we study the role of fast synaptic inhibitory neurotransmission in the generation of breathing pattern by blocking GABA(A) and glycine receptors in the preBötzinger complex (preBötC), a site essential for generation of normal breathing pattern, and in the neighboring Bötzinger complex (BötC). The breathing rhythm continued following this blockade, but the lung inflation-induced Breuer-Hering inspiratory inhibitory reflex was suppressed. The antagonists were efficacious, as this blockade abolished the profound effects of the exogenously applied GABA(A) receptor agonist muscimol or glycine, either of which under control conditions stopped breathing in vagus-intact or vagotomized, anesthetized, spontaneously breathing adult rats. In vagotomized rats, GABA(A)ergic and glycinergic antagonists had little, if any, effect on rhythm. The effect in vagus-intact rats was to slow the rhythm to a pace equivalent to that seen after suppression of the aforementioned Breuer-Hering inflation reflex. We conclude that postsynaptic inhibition within the preBötC and BötC is not essential for generation of normal respiratory rhythm in intact mammals. We suggest the primary role of inhibition is in shaping the pattern of respiratory motor output, assuring its stability, and in mediating reflex or volitional apnea, but not in the generation of rhythm per se. PMID:23536061

  18. ROLE OF INHIBITION IN RESPIRATORY PATTERN GENERATION

    PubMed Central

    Janczewski, Wiktor A.; Tashima, Alexis; Hsu, Paul; Cui, Yan; Feldman, Jack L.

    2013-01-01

    Postsynaptic inhibition is a key element of neural circuits underlying behavior, with 20-50% of all mammalian (non-granule) neurons considered inhibitory. For rhythmic movements in mammals, e.g., walking, swimming, suckling, chewing, breathing, inhibition is often hypothesized to play an essential rhythmogenic role. Here we study the role of fast synaptic inhibitory neurotransmission in the generation of breathing pattern by blocking GABAA and glycine receptors in the preBötzinger Complex (preBötC), a site essential for generation of normal breathing pattern, and in the neighboring Bötzinger Complex (BötC). The breathing rhythm continued following this blockade, but the lung inflation-induced Breuer-Hering inspiratory-inhibitory reflex was suppressed. The antagonists were efficacious, as this blockade abolished the profound effects of the exogenously applied GABAA receptor agonist muscimol or glycine, either of which under control conditions stopped breathing in vagus-intact or vagotomized, anesthetized, spontaneously breathing adult rats. In vagotomized rats, GABAAergic and glycinergic antagonists had little, if any, effect on rhythm. The effect in vagus intact rats was to slow the rhythm to a pace equivalent to that seen after suppression of the aforementioned Breuer-Hering inflation reflex. We conclude that postsynaptic inhibition within the preBötC and BötC is not essential for generation of normal respiratory rhythm in intact mammals. We suggest the primary role of inhibition is in shaping the pattern of respiratory motor output, assuring its stability, and in mediating reflex or volitional apnea, but not in the generation of rhythm per se. PMID:23536061

  19. Test Generator for MATLAB Simulations

    NASA Technical Reports Server (NTRS)

    Henry, Joel

    2011-01-01

    MATLAB Automated Test Tool, version 3.0 (MATT 3.0) is a software package that provides automated tools that reduce the time needed for extensive testing of simulation models that have been constructed in the MATLAB programming language by use of the Simulink and Real-Time Workshop programs. MATT 3.0 runs on top of the MATLAB engine application-program interface to communicate with the Simulink engine. MATT 3.0 automatically generates source code from the models, generates custom input data for testing both the models and the source code, and generates graphs and other presentations that facilitate comparison of the outputs of the models and the source code for the same input data. Context-sensitive and fully searchable help is provided in HyperText Markup Language (HTML) format.

  20. Altered gravity highlights central pattern generator mechanisms.

    PubMed

    White, Olivier; Bleyenheuft, Yannick; Ronsse, Renaud; Smith, Allan M; Thonnard, Jean-Louis; Lefèvre, Philippe

    2008-11-01

    In many nonprimate species, rhythmic patterns of activity such as locomotion or respiration are generated by neural networks at the spinal level. These neural networks are called central pattern generators (CPGs). Under normal gravitational conditions, the energy efficiency and the robustness of human rhythmic movements are due to the ability of CPGs to drive the system at a pace close to its resonant frequency. This property can be compared with oscillators running at resonant frequency, for which the energy is optimally exchanged with the environment. However, the ability of the CPG to adapt the frequency of rhythmic movements to new gravitational conditions has never been studied. We show here that the frequency of a rhythmic movement of the upper limb is systematically influenced by the different gravitational conditions created in parabolic flight. The period of the arm movement is shortened with increasing gravity levels. In weightlessness, however, the period is more dependent on instructions given to the participants, suggesting a decreased influence of resonant frequency. Our results are in agreement with a computational model of a CPG coupled to a simple pendulum under the control of gravity. We demonstrate that the innate modulation of rhythmic movements by CPGs is highly flexible across gravitational contexts. This further supports the involvement of CPG mechanisms in the achievement of efficient rhythmic arm movements. Our contribution is of major interest for the study of human rhythmic activities, both in a normal Earth environment and during microgravity conditions in space. PMID:18650309

  1. Multivariable Harmonic Balance for Central Pattern Generators?

    PubMed Central

    Iwasaki, Tetsuya

    2009-01-01

    The central pattern generator (CPG) is a nonlinear oscillator formed by a group of neurons, providing a fundamental control mechanism underlying rhythmic movements in animal locomotion. We consider a class of CPGs modeled by a set of interconnected identical neurons. Based on the idea of multivariable harmonic balance, we show how the oscillation profile is related to the connectivity matrix that specifies the architecture and strengths of the interconnections. Specifically, the frequency, amplitudes, and phases are essentially encoded in terms of a pair of eigenvalue and eigenvector. This basic principle is used to estimate the oscillation profile of a given CPG model. Moreover, a systematic method is proposed for designing a CPG-based nonlinear oscillator that achieves a prescribed oscillation profile. PMID:19956774

  2. Temperature distortion generator for turboshaft engine testing

    NASA Technical Reports Server (NTRS)

    Klann, G. A.; Barth, R. L.; Biesiadny, T. J.

    1984-01-01

    The procedures and unique hardware used to conduct an experimental investigation into the response of a small-turboshaft-engine compression system to various hot gas ingestion patterns are presented. The temperature distortion generator described herein uses gaseous hydrogen to create both steady-state and time-variant, or transient, temperature distortion at the engine inlet. The range of transient temperature ramps produced by the distortion generator during the engine tests was from less than 111 deg K/sec (200 deg R/sec) to above 611 deg K/sec (1100 deg R/sec); instantaneous temperatures to 422 deg K (760 deg R) above ambient were generated. The distortion generator was used to document the maximum inlet temperatures and temperature rise rates that the compression system could tolerate before the onset of stall for various circumferential distortions as well as the compressor system response during stall.

  3. Contribution of motoneuron intrinsic properties to fictive motor pattern generation

    PubMed Central

    Calabrese, Ronald L.

    2011-01-01

    Previously, we reported a canonical ensemble model of the heart motoneurons that underlie heartbeat in the medicinal leech. The model motoneurons contained a minimal set of electrical intrinsic properties and received a synaptic input pattern based on measurements performed in the living system. Although the model captured the synchronous and peristaltic motor patterns observed in the living system, it did not match quantitatively the motor output observed. Because the model motoneurons had minimal intrinsic electrical properties, the mismatch between model and living system suggests a role for additional intrinsic properties in generating the motor pattern. We used the dynamic clamp to test this hypothesis. We introduced the same segmental input pattern used in the model to motoneurons isolated pharmacologically from their endogenous input in the living system. We show that, although the segmental input pattern determines the segmental phasing differences observed in motoneurons, the intrinsic properties of the motoneurons play an important role in determining their phasing, particularly when receiving the synchronous input pattern. We then used trapezoidal input waveforms to show that the intrinsic properties present in the living system promote phase advances compared with our model motoneurons. Electrical coupling between heart motoneurons also plays a role in shaping motoneuron output by synchronizing the activity of the motoneurons within a segment. These experiments provide a direct assessment of how motoneuron intrinsic properties interact with their premotor pattern of synaptic drive to produce rhythmic output. PMID:21562194

  4. Automatic optometer operates with infrared test pattern

    NASA Technical Reports Server (NTRS)

    Cornsweet, T. N.; Crane, H. D.

    1970-01-01

    Refractive strength of human eye is monitored by optometer that automatically and continuously images infrared test pattern onto the retina. Condition of focus of the eye at any instant is determined from optometer settings needed to maintain focus of the pattern on the retina.

  5. Testing whether and when abstract symmetric patterns produce affective responses.

    PubMed

    Bertamini, Marco; Makin, Alexis; Pecchinenda, Anna

    2013-01-01

    Symmetry has a central role in visual art, it is often linked to beauty, and observers can detect it efficiently in the lab. We studied what kind of fast and automatic responses are generated by visual presentation of symmetrical patterns. Specifically, we tested whether a brief presentation of novel symmetrical patterns engenders positive affect using a priming paradigm. The abstract patterns were used as primes in a pattern-word interference task. To ensure that familiarity was not a factor, no pattern and no word was ever repeated within each experiment. The task was to classify words that were selected to have either positive or negative valence. We tested irregular patterns, patterns containing vertical and horizontal reflectional symmetry, and patterns containing a 90 deg rotation. In a series of 7 experiments we found that the effect of affective congruence was present for both types of regularity but only when observers had to classify the regularity of the pattern after responding to the word. The findings show that processing abstract symmetrical shapes or random pattern can engender positive or negative affect as long as the regularity of the pattern is a feature that observers have to attend to and classify. PMID:23840892

  6. Generation 1.5 Written Error Patterns: A Comparative Study

    ERIC Educational Resources Information Center

    Doolan, Stephen M.; Miller, Donald

    2012-01-01

    In an attempt to contribute to existing research on Generation 1.5 students, the current study uses quantitative and qualitative methods to compare error patterns in a corpus of Generation 1.5, L1, and L2 community college student writing. This error analysis provides one important way to determine if error patterns in Generation 1.5 student…

  7. Generating Spatiotemporal Joint Torque Patterns from Dynamical Synchronization of Distributed Pattern Generators

    PubMed Central

    Pitti, Alexandre; Lungarella, Max; Kuniyoshi, Yasuo

    2009-01-01

    Pattern generators found in the spinal cord are no more seen as simple rhythmic oscillators for motion control. Indeed, they achieve flexible and dynamical coordination in interaction with the body and the environment dynamics giving to rise motor synergies. Discovering the mechanisms underlying the control of motor synergies constitutes an important research question not only for neuroscience but also for robotics: the motors coordination of high dimensional robotic systems is still a drawback and new control methods based on biological solutions may reduce their overall complexity. We propose to model the flexible combination of motor synergies in embodied systems via partial phase synchronization of distributed chaotic systems; for specific coupling strength, chaotic systems are able to phase synchronize their dynamics to the resonant frequencies of one external force. We take advantage of this property to explore and exploit the intrinsic dynamics of one specified embodied system. In two experiments with bipedal walkers, we show how motor synergies emerge when the controllers phase synchronize to the body's dynamics, entraining it to its intrinsic behavioral patterns. This stage is characterized by directed information flow from the sensors to the motors exhibiting the optimal situation when the body dynamics drive the controllers (mutual entrainment). Based on our results, we discuss the relevance of our findings for modeling the modular control of distributed pattern generators exhibited in the spinal cord, and for exploring the motor synergies in robots. PMID:20011216

  8. Vapor-Generator Wand Helps To Reveal Airflow Patterns

    NASA Technical Reports Server (NTRS)

    Robelen, David B.

    1993-01-01

    In vapor-generator wand, liquid propylene glycol flows into electrically heated stainless-steel tube. Liquid boils in heated tube, and emerging vapor forms dense, smoke-like fog used to make airflow patterns visible. Built in variety of sizes, suitable for uses ranging from tabletop demonstrations to research in wind tunnels. For best viewing, plume illuminated by bright, focused incandescent spotlight at right angle to viewing direction. Viewing further enhanced by coating walls of test chamber with flat, dark color to minimize reflections and increase contrast.

  9. Pattern Generation by Dissipative Parametric Instability.

    PubMed

    Perego, A M; Tarasov, N; Churkin, D V; Turitsyn, S K; Staliunas, K

    2016-01-15

    Nonlinear instabilities are responsible for spontaneous pattern formation in a vast number of natural and engineered systems, ranging from biology to galaxy buildup. We propose a new instability mechanism leading to pattern formation in spatially extended nonlinear systems, which is based on a periodic antiphase modulation of spectrally dependent losses arranged in a zigzag way: an effective filtering is imposed at symmetrically located wave numbers k and -k in alternating order. The properties of the dissipative parametric instability differ from the features of both key classical concepts of modulation instabilities, i.e., the Benjamin-Feir instability and the Faraday instabiltyity. We demonstrate how the dissipative parametric instability can lead to the formation of stable patterns in one- and two-dimensional systems. The proposed instability mechanism is generic and can naturally occur or can be implemented in various physical systems. PMID:26824573

  10. Pattern Generation by Dissipative Parametric Instability

    NASA Astrophysics Data System (ADS)

    Perego, A. M.; Tarasov, N.; Churkin, D. V.; Turitsyn, S. K.; Staliunas, K.

    2016-01-01

    Nonlinear instabilities are responsible for spontaneous pattern formation in a vast number of natural and engineered systems, ranging from biology to galaxy buildup. We propose a new instability mechanism leading to pattern formation in spatially extended nonlinear systems, which is based on a periodic antiphase modulation of spectrally dependent losses arranged in a zigzag way: an effective filtering is imposed at symmetrically located wave numbers k and -k in alternating order. The properties of the dissipative parametric instability differ from the features of both key classical concepts of modulation instabilities, i.e., the Benjamin-Feir instability and the Faraday instabiltyity. We demonstrate how the dissipative parametric instability can lead to the formation of stable patterns in one- and two-dimensional systems. The proposed instability mechanism is generic and can naturally occur or can be implemented in various physical systems.

  11. Generation Speed in Raven's Progressive Matrices Test.

    ERIC Educational Resources Information Center

    Verguts, Tom; De Boeck, Paul; Maris, Eric

    1999-01-01

    Studied the role of response fluency on results of the Raven's Advanced Progressive Matrices (APM) Test by comparing scores on a test of generation speed (speed of generating rules that govern the items) with APM test performance for 127 Belgian undergraduates. Discusses the importance of generation speed in intelligence. (SLD)

  12. Generation of Adaptive Gait Patterns for Quadruped Robot with CPG Network including Motor Dynamic Model

    NASA Astrophysics Data System (ADS)

    Son, Yurak; Kamano, Takuya; Yasuno, Takashi; Suzuki, Takayuki; Harada, Hironobu

    This paper describes the generation of adaptive gait patterns using new Central Pattern Generators (CPGs) including motor dynamic models for a quadruped robot under various environment. The CPGs act as the flexible oscillators of the joints and make the desired angle of the joints. The CPGs are mutually connected each other, and the sets of their coupling parameters are adjusted by genetic algorithm so that the quadruped robot can realize the stable and adequate gait patterns. As a result of generation, the suitable CPG networks for not only a walking straight gait pattern but also rotation gait patterns are obtained. Experimental results demonstrate that the proposed CPG networks are effective to automatically adjust the adaptive gait patterns for the tested quadruped robot under various environment. Furthermore, the target tracking control based on image processing is achieved by combining the generated gait patterns.

  13. Automated Test-Form Generation

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Diao, Qi

    2011-01-01

    In automated test assembly (ATA), the methodology of mixed-integer programming is used to select test items from an item bank to meet the specifications for a desired test form and optimize its measurement accuracy. The same methodology can be used to automate the formatting of the set of selected items into the actual test form. Three different…

  14. Generator acceptance test and inspection report

    SciTech Connect

    Johns, B.R.

    1997-07-24

    This Acceptance Test Report(ATR) is the completed testing and inspection of the new portable generator. The testing and inspection is to verify that the generator provided by the vendor meets the requirements of specification WHC-S-0252, Revision 2. Attached is various other documentation to support the inspection and testing.

  15. Electronic load for testing power generating devices

    NASA Technical Reports Server (NTRS)

    Friedman, E. B.; Stepfer, G.

    1968-01-01

    Instrument tests various electric power generating devices by connecting the devices to the input of the load and comparing their outputs with a reference voltage. The load automatically adjusts until voltage output of the power generating device matches the reference.

  16. Automated branching pattern report generation for laparoscopic surgery assistance

    NASA Astrophysics Data System (ADS)

    Oda, Masahiro; Matsuzaki, Tetsuro; Hayashi, Yuichiro; Kitasaka, Takayuki; Misawa, Kazunari; Mori, Kensaku

    2015-05-01

    This paper presents a method for generating branching pattern reports of abdominal blood vessels for laparoscopic gastrectomy. In gastrectomy, it is very important to understand branching structure of abdominal arteries and veins, which feed and drain specific abdominal organs including the stomach, the liver and the pancreas. In the real clinical stage, a surgeon creates a diagnostic report of the patient anatomy. This report summarizes the branching patterns of the blood vessels related to the stomach. The surgeon decides actual operative procedure. This paper shows an automated method to generate a branching pattern report for abdominal blood vessels based on automated anatomical labeling. The report contains 3D rendering showing important blood vessels and descriptions of branching patterns of each vessel. We have applied this method for fifty cases of 3D abdominal CT scans and confirmed the proposed method can automatically generate branching pattern reports of abdominal arteries.

  17. Generative models versus underlying symmetries to explain biological pattern.

    PubMed

    Frank, S A

    2014-06-01

    Mathematical models play an increasingly important role in the interpretation of biological experiments. Studies often present a model that generates the observations, connecting hypothesized process to an observed pattern. Such generative models confirm the plausibility of an explanation and make testable hypotheses for further experiments. However, studies rarely consider the broad family of alternative models that match the same observed pattern. The symmetries that define the broad class of matching models are in fact the only aspects of information truly revealed by observed pattern. Commonly observed patterns derive from simple underlying symmetries. This article illustrates the problem by showing the symmetry associated with the observed rate of increase in fitness in a constant environment. That underlying symmetry reveals how each particular generative model defines a single example within the broad class of matching models. Further progress on the relation between pattern and process requires deeper consideration of the underlying symmetries. PMID:24750332

  18. Characteristic flow patterns generated by macrozoobenthic structures

    NASA Astrophysics Data System (ADS)

    Friedrichs, M.; Graf, G.

    2009-02-01

    A laboratory flume channel, equipped with an acoustic Doppler flow sensor and a bottom scanning laser, was used for detailed, non-intrusive flow measurements (at 2 cm s - 1 and 10 cm s - 1 ) around solitary biogenic structures, combined with high-resolution mapping of the structure shape and position. The structures were replicates of typical macrozoobenthic species commonly found in the Mecklenburg Bight and with a presumed influence on both, the near-bed current regime and sediment transport dynamics: a worm tube, a snail shell, a mussel, a sand mound, a pit, and a cross-stream track furrow. The flow was considerably altered locally by the different protruding structures (worm tube, snail, mussel and mound). They reduced the horizontal approach velocity by 72% to 79% in the wake zone at about 1-2 cm height, and the flow was deflected around the structures with vertical and lateral velocities of up to 10% and 20% of the free-stream velocity respectively in a region adjacent to the structures. The resulting flow separation (at flow Reynolds number of about 4000 and 20,000 respectively) divided an outer deflection region from an inner region with characteristic vortices and the wake region. All protruding structures showed this general pattern, but also produced individual characteristics. Conversely, the depressions (track and pit) only had a weak influence on the local boundary layer flow, combined with a considerable flow reduction within their cavities (between 29% and 53% of the free-stream velocity). A longitudinal vortex formed, below which a stagnant space was found. The average height affected by the structure-related mass flow rate deficit for the two velocities was 1.6 cm and 1.3 cm respectively (80% of height and 64%) for the protruding structures and 0.6 cm and 0.9 cm (90% and 127% of depth) for the depressions. Marine benthic soft-bottom macrozoobenthos species are expected to benefit from the flow modifications they induce, particularly in terms of food particle capture due to altered particle pathways and residence times, but also for the exchange of gases, solutes and spawn. The present results confirm previous studies on flow interaction effects of various biogenic structures, and they add a deeper level of detail for a better understanding of the fine-scale effects.

  19. The Next Generation of Testing

    ERIC Educational Resources Information Center

    Tucker, Bill

    2009-01-01

    New technology-enabled assessments offer the potential to understand more than just whether a student answered a test question right or wrong. Using multiple forms of media that enable both visual and graphical representations, these assessments present complex, multistep problems for students to solve and collect detailed information about an…

  20. Revised evaluation of steam generator testing alternatives

    SciTech Connect

    1981-01-01

    A scoping evaluation was made of various facility alternatives for test of LMFBR prototype steam generators and models. Recommendations are given for modifications to EBR-II and SCTI (Sodium Components Test Installation) for prototype SG testing, and for few-tube model testing. (DLC)

  1. A simple approach for stochastic generation of spatial rainfall patterns

    NASA Astrophysics Data System (ADS)

    Tarpanelli, Angelica; Franchini, Marco; Camici, Stefania; Brocca, Luca; Melone, Florisa; Moramarco, Tommaso

    2010-05-01

    The high floods occurred in the last years in many regions of the world have increased the interest of local, national and international authorities on the flood and risk assessment. In this context, the estimation of the design flood to be adopted represents a crucial factor, mainly for ungauged or poorly gauged catchments where sufficiently long discharge time series are missing. Due to the wider availability of rainfall data, rainfall-runoff models represent a possible tool to reduce the relevant uncertainty involved in the flood frequency analysis. Recently, new methodologies based on the stochastic generation of rainfall and temperature data have been proposed. The inferred information can be used as input for a continuous hydrological model to generate a synthetic time series of discharge and, hence, the flood frequency distribution at a given site. As far as the rainfall generation is concerned, for catchments of limited size, a single site model, as the Neyman-Scott Rectangular Pulses (NSRP), can be applied. It is characterized by a flexible structure in which the model parameters are broadly related to the underlying physical features observed in the rainfall field and the statistical properties of rainfall time series over a range of time scales are preserved. However, when larger catchments are considered, an extension into the two-dimensional space is required. This issue can be addressed by using the Spatial-Temporal Neyman-Scott Rectangular Pulses (STNSRP) model that, however, is not easy to be applied and requires a high computational effort. Therefore, simple techniques to obtain a spatial rainfall pattern starting from the more simple single-site NSRP are welcome. In this study, in order to take account of the spatial correlation that is needed when spatial rainfall patterns should be generated, the practical method of the rank correlation proposed by Iman and Conover (IC), was applied. The method is able to introduce a desired level of correlation between data, keeping its simplicity in the application. Moreover the method can be used for all types of input probability distribution and it allows the marginal distributions to remain intact. The IC method was applied to hourly and daily rainfall time series. In the second case, a temporal disaggregation technique has been carried out to obtain the hourly data. To test the proposed methodology, rainfall data from one catchment located in the Upper Tiber River Basin was considered. At first, long stochastic rainfall time series were generated through the NSRP model for several sites, then the IC method was applied to generate spatially correlated rainfall time series. The main statistics of these time series were compared both with the observed data and with ones generated by using the more complex STNSRP model. In particular, results were expressed in terms of depth-duration-frequency (DDF) curves obtained for the areal mean rainfall that are of upmost importance for the design flood estimation. The high performance shown by the IC approach in reproducing the observed data along with its simplicity of application make it a valuable tool for the estimation of spatial rainfall patterns.

  2. Generating Test Templates via Automated Theorem Proving

    NASA Technical Reports Server (NTRS)

    Kancherla, Mani Prasad

    1997-01-01

    Testing can be used during the software development process to maintain fidelity between evolving specifications, program designs, and code implementations. We use a form of specification-based testing that employs the use of an automated theorem prover to generate test templates. A similar approach was developed using a model checker on state-intensive systems. This method applies to systems with functional rather than state-based behaviors. This approach allows for the use of incomplete specifications to aid in generation of tests for potential failure cases. We illustrate the technique on the cannonical triangle testing problem and discuss its use on analysis of a spacecraft scheduling system.

  3. Control and generation of drifting patterns by asymmetrical Fourier filtering

    NASA Astrophysics Data System (ADS)

    Louvergneaux, E.; Odent, V.; Coulibaly, S.; Bortolozzo, U.; Residori, S.

    2016-01-01

    We report the theoretical and experimental demonstration of one-dimensional drifting patterns generated by asymmetrical Fourier filtering in the transverse plane of an optical feedback system with a Kerr type nonlinearity. We show, with good agreement between our theoretical (analytics and numerics) calculations and experimental observations that at the primary instability threshold the group velocity is always different from zero. Consequently, the system is convective at this threshold, then exhibits drifting patterns.

  4. Digitally based pattern generator for an electron-beam welder

    SciTech Connect

    Whitten, L.G. III

    1981-02-19

    A digitally based deflection generator for an electron-beam welder is presented. Up to seven patterns of any shape are stored in programmable read-only memory (PROM). The pattern resolution is 39% at frequencies from 10 Hz to 1 kHz and can be x-t, y-t, or x-y formed. Frequency and pattern selections may be chosen by the welder computer or manually selected on the front panel. The ability to repeatedly synchronize two waveforms of any shape and frequency enables an unlimited variety of welds.

  5. Self-testing quantum random number generator.

    PubMed

    Lunghi, Tommaso; Brask, Jonatan Bohr; Lim, Charles Ci Wen; Lavigne, Quentin; Bowles, Joseph; Martin, Anthony; Zbinden, Hugo; Brunner, Nicolas

    2015-04-17

    The generation of random numbers is a task of paramount importance in modern science. A central problem for both classical and quantum randomness generation is to estimate the entropy of the data generated by a given device. Here we present a protocol for self-testing quantum random number generation, in which the user can monitor the entropy in real time. Based on a few general assumptions, our protocol guarantees continuous generation of high quality randomness, without the need for a detailed characterization of the devices. Using a fully optical setup, we implement our protocol and illustrate its self-testing capacity. Our work thus provides a practical approach to quantum randomness generation in a scenario of trusted but error-prone devices. PMID:25933297

  6. Self-Testing Quantum Random Number Generator

    NASA Astrophysics Data System (ADS)

    Lunghi, Tommaso; Brask, Jonatan Bohr; Lim, Charles Ci Wen; Lavigne, Quentin; Bowles, Joseph; Martin, Anthony; Zbinden, Hugo; Brunner, Nicolas

    2015-04-01

    The generation of random numbers is a task of paramount importance in modern science. A central problem for both classical and quantum randomness generation is to estimate the entropy of the data generated by a given device. Here we present a protocol for self-testing quantum random number generation, in which the user can monitor the entropy in real time. Based on a few general assumptions, our protocol guarantees continuous generation of high quality randomness, without the need for a detailed characterization of the devices. Using a fully optical setup, we implement our protocol and illustrate its self-testing capacity. Our work thus provides a practical approach to quantum randomness generation in a scenario of trusted but error-prone devices.

  7. Using Test Generating Software for Assessment

    NASA Astrophysics Data System (ADS)

    Singh Aurora, Tarlok

    2007-04-01

    Assessment is an important part of teaching and learning. Designing suitable tests and quizzes for assessment is a time consuming task. With faculty's much commitment at work, sometimes it is not easy to find enough time to design a good test before the test day. Searching for and modifying older tests can take considerable amount of time. There is a need to develop a customized test bank that one could use to generate a quiz or test quickly before class time or before a test. A number of commercial software is available for e-learning that has this capability. Some of these are - Test Generator, Examview, Test Pro Developer etc. Application of Examview software in developing a test bank for physics will be presented. A physics test bank, with applications in other disciplines, can be gradually built over time and used to create a test or quiz quickly. Multiple scrambled versions of a single test (and answer sheets) can be created to discourage cheating in a large class setting. The presentation will show how to build a test bank.

  8. MYSID TWO-GENERATION TEST GUIDELINE

    EPA Science Inventory

    McKenney, Charles L., Jr. In press. Mysid Two-Generation Test Guideline. OECD Expert Group on Invertebrate Testing for Endocrine Disruptors, Organisation for Economic Co-operation and Development, Paris, France. 17 p. (ERL,GB 1215).

    This guideline describes a two-generati...

  9. Alcohol LOX Steam Generator Test Experience

    NASA Astrophysics Data System (ADS)

    Schaefer, K.; Dommers, M.

    2004-10-01

    At the DLR test centre in Lampoldshausen there is a long experience in the development of rocket steam generators as a main subsystem for the altitude simulation. The rocket steam generators make it possible to supply the required quantities of steam at short notice with reduced investment and operating costs. The rocket steam generators are based on the combustion of liquid oxygen (LOX) and ethyl alcohol (ALC). The paper deals with the experience of the development of the steam generators and the operation at the altitude simulation P1.0 for satellite propulsion and P4.2 for altitude simulation of AESTUS upper stage engine.

  10. Central pattern generator for vocalization: Is there a vertebrate morphotype?

    PubMed Central

    Bass, Andrew H.

    2014-01-01

    Animals that generate acoustic signals for social communication are faced with two essential tasks: generate a temporally precise signal and inform the auditory system about the occurrence of one’s own sonic signal. Recent studies of sound producing fishes delineate a hindbrain network comprised of anatomically distinct compartments coding equally distinct neurophysiological properties that allow an organism to meet these behavioral demands. A set of neural characters comprising a vocal-sonic central pattern generator (CPG) morphotype is proposed for fishes and tetrapods that shares evolutionary developmental origins with pectoral appendage motor systems. PMID:25050813

  11. Formal methods for test case generation

    NASA Technical Reports Server (NTRS)

    Rushby, John (Inventor); De Moura, Leonardo Mendonga (Inventor); Hamon, Gregoire (Inventor)

    2011-01-01

    The invention relates to the use of model checkers to generate efficient test sets for hardware and software systems. The method provides for extending existing tests to reach new coverage targets; searching *to* some or all of the uncovered targets in parallel; searching in parallel *from* some or all of the states reached in previous tests; and slicing the model relative to the current set of coverage targets. The invention provides efficient test case generation and test set formation. Deep regions of the state space can be reached within allotted time and memory. The approach has been applied to use of the model checkers of SRI's SAL system and to model-based designs developed in Stateflow. Stateflow models achieving complete state and transition coverage in a single test case are reported.

  12. Diesel generator trailer acceptance test procedure

    SciTech Connect

    Kostelnik, A.J.

    1994-09-23

    This Acceptance Test Procedure (ATP) will document compliance with the requirements of WHC-S-0252 Rev. 1 and ECNs 609271, and 609272. The equipment being tested is a 150KW Diesel Generator mounted on a trailer with switchgear. The unit was purchased as a Design and Fabrication procurement activity. The ATP was written by the Seller and will be performed by the Seller with representatives of the Westinghouse Hanford Company witnessing the test at the Seller`s location.

  13. Modeling Scalable Pattern Generation in DNA Reaction Networks

    PubMed Central

    Allen, Peter B.; Chen, Xi; Simpson, Zack B.; Ellington, Andrew D.

    2013-01-01

    We have developed a theoretical framework for developing patterns in multiple dimensions using controllable diffusion and designed reactions implemented in DNA. This includes so-called strand displacement reactions in which one single-stranded DNA hybridizes to a hemi-duplex DNA and displaces another single-stranded DNA, reversibly or irreversibly. These reactions can be designed to proceed with designed rate and molecular specificity. By also controlling diffusion by partial complementarity to a stationary, cross-linked DNA, we can generate predictable patterns. We demonstrate this with several simulations showing deterministic, predictable shapes in space. PMID:25506295

  14. THE IDENTIFICATION AND TESTING OF INTERACTION PATTERNS

    EPA Science Inventory

    This paper presents a method for identifying and assessing the significance of interaction patterns among various chemicals and chemical classes of importance to regulatory toxicologists. To this end, efforts were made to assemble and evaluate experimental data on toxicologically...

  15. Override of spontaneous respiratory pattern generator reduces cardiovascular parasympathetic influence

    NASA Technical Reports Server (NTRS)

    Patwardhan, A. R.; Vallurupalli, S.; Evans, J. M.; Bruce, E. N.; Knapp, C. F.

    1995-01-01

    We investigated the effects of voluntary control of breathing on autonomic function in cardiovascular regulation. Variability in heart rate was compared between 5 min of spontaneous and controlled breathing. During controlled breathing, for 5 min, subjects voluntarily reproduced their own spontaneous breathing pattern (both rate and volume on a breath-by-breath basis). With the use of this experimental design, we could unmask the effects of voluntary override of the spontaneous respiratory pattern generator on autonomic function in cardiovascular regulation without the confounding effects of altered respiratory pattern. Results from 10 subjects showed that during voluntary control of breathing, mean values of heart rate and blood pressure increased, whereas fractal and spectral powers in heart rate in the respiratory frequency region decreased. End-tidal PCO2 was similar during spontaneous and controlled breathing. These results indicate that the act of voluntary control of breathing decreases the influence of the vagal component, which is the principal parasympathetic influence in cardiovascular regulation.

  16. Neural Sequence Generation Using Spatiotemporal Patterns of Inhibition

    PubMed Central

    Cannon, Jonathan; Kopell, Nancy; Gardner, Timothy; Markowitz, Jeffrey

    2015-01-01

    Stereotyped sequences of neural activity are thought to underlie reproducible behaviors and cognitive processes ranging from memory recall to arm movement. One of the most prominent theoretical models of neural sequence generation is the synfire chain, in which pulses of synchronized spiking activity propagate robustly along a chain of cells connected by highly redundant feedforward excitation. But recent experimental observations in the avian song production pathway during song generation have shown excitatory activity interacting strongly with the firing patterns of inhibitory neurons, suggesting a process of sequence generation more complex than feedforward excitation. Here we propose a model of sequence generation inspired by these observations in which a pulse travels along a spatially recurrent excitatory chain, passing repeatedly through zones of local feedback inhibition. In this model, synchrony and robust timing are maintained not through redundant excitatory connections, but rather through the interaction between the pulse and the spatiotemporal pattern of inhibition that it creates as it circulates the network. These results suggest that spatially and temporally structured inhibition may play a key role in sequence generation. PMID:26536029

  17. Neural Sequence Generation Using Spatiotemporal Patterns of Inhibition.

    PubMed

    Cannon, Jonathan; Kopell, Nancy; Gardner, Timothy; Markowitz, Jeffrey

    2015-11-01

    Stereotyped sequences of neural activity are thought to underlie reproducible behaviors and cognitive processes ranging from memory recall to arm movement. One of the most prominent theoretical models of neural sequence generation is the synfire chain, in which pulses of synchronized spiking activity propagate robustly along a chain of cells connected by highly redundant feedforward excitation. But recent experimental observations in the avian song production pathway during song generation have shown excitatory activity interacting strongly with the firing patterns of inhibitory neurons, suggesting a process of sequence generation more complex than feedforward excitation. Here we propose a model of sequence generation inspired by these observations in which a pulse travels along a spatially recurrent excitatory chain, passing repeatedly through zones of local feedback inhibition. In this model, synchrony and robust timing are maintained not through redundant excitatory connections, but rather through the interaction between the pulse and the spatiotemporal pattern of inhibition that it creates as it circulates the network. These results suggest that spatially and temporally structured inhibition may play a key role in sequence generation. PMID:26536029

  18. Next Generation Drivetrain Development and Test Program

    SciTech Connect

    Keller, Jonathan; Erdman, Bill; Blodgett, Doug; Halse, Chris; Grider, Dave

    2015-11-03

    This presentation was given at the Wind Energy IQ conference in Bremen, Germany, November 30 through December 2, 2105. It focused on the next-generation drivetrain architecture and drivetrain technology development and testing (including gearbox and inverter software and medium-voltage inverter modules.

  19. Stochastic Generation of Wind Patterns over Lake Geneva

    NASA Astrophysics Data System (ADS)

    Barry, D. A.; Barry, C. E.; Razmi, A. M.; Lemmin, U.; Le Dantec, N.

    2011-12-01

    Lake Geneva (length 74 km on the long east-west axis, surface area 562 km2, volume 89 km3) is a freshwater lake bordered by Switzerland and France. The lake's hydrodynamics are forced principally by wind and seasonality, with inflows and the Coriolis effect playing relatively minor roles. Of the major forcings, wind is highly variable due to the rapid changes in topography around the lake, with mountains in the east and relatively gentle landscapes in the west. Numerous field investigations have revealed that the lake's currents, which are dominated by the wind, are likewise highly variable. In particular, analysis of field measurements of Lake Geneva's wind and currents found that the lake's currents during the summer stratification period are consistent with diurnal winds and long-fetch synoptic events (Lemmin and D'Adamo, Annales Geophysicae, 1996). Obviously, a quantitative understanding of the wind forcing is a prerequisite for evaluating the current patterns in the lake. Hourly wind patterns (produced using the non-hydrostatic, fully compressible COSMO model) at 10 m above the lake were provided by MeteoSuisse (the Swiss meteorological service) on a 2.2 km2 grid for 2009-2010. These patterns were categorized using the k-means data-mining method, with each pattern assigned an arbitrary integer index 1, 2, 3, etc., along with the pattern's frequency. For later use, all wind fields corresponding to a given pattern were grouped into bins. It was found that the index frequencies could be approximated by a Poisson distribution with a characteristic temporal autocorrelation time of around 15-20 hours. More specifically, the wind pattern autocorrelation has an initial rapid, power law-like decline (~?t, where ? ? 0.8 and t is the lag in hours) for about 24 hours, then a slow decay. The main features of this behavior (Poisson process with a power-law autocorrelation) were captured by an integer auto-regressive process, the INAR(1) model. This model was used as a stochastic generator of wind-pattern indices, i.e., the INAR(1) model produces a sequence of integers, each of which corresponds to a wind pattern. For a given index, the aforementioned binned COSMO wind fields were sampled randomly to produce the stochastic wind-field sequence.

  20. 21 CFR 892.1420 - Radionuclide test pattern phantom.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radionuclide test pattern phantom. 892.1420 Section 892.1420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1420 Radionuclide test pattern...

  1. 21 CFR 892.1420 - Radionuclide test pattern phantom.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radionuclide test pattern phantom. 892.1420 Section 892.1420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1420 Radionuclide test pattern...

  2. 21 CFR 892.1420 - Radionuclide test pattern phantom.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radionuclide test pattern phantom. 892.1420 Section 892.1420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1420 Radionuclide test pattern...

  3. 21 CFR 892.1420 - Radionuclide test pattern phantom.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radionuclide test pattern phantom. 892.1420 Section 892.1420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1420 Radionuclide test pattern...

  4. 21 CFR 892.1420 - Radionuclide test pattern phantom.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radionuclide test pattern phantom. 892.1420 Section 892.1420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1420 Radionuclide test pattern...

  5. The principle that generates dissimilar patterns inside aggregates of organisms

    NASA Astrophysics Data System (ADS)

    Miguel, Antonio F.; Bejan, Adrian

    2009-03-01

    Pattern formation and self-organization are phenomena that occur across the board, in animate and inanimate systems. In this paper, we rely on the constructal law to explain the generation of patterns (shapes, structures) in aggregates of organisms-pedestrian crowds and stony corals. In pedestrian crowds a variety of patterns are often observed, from ‘chaotic’ appearances to spontaneous organization in lanes of uniform walking direction. Stony corals and other organisms also present intraspecific variability in shape. We show that flow systems develop in time patterns which provide easier access to the nutrients and space, within a set of constraints imposed by each situation. Flow systems have the freedom to morph their shape in search for architectures that allows them to have greater access to the space that they inhabit. We identify the mechanisms allowing pedestrians to evolve in space and time. We also show that stony corals may develop branched or spherical shapes, depending on which shape performs best in response to the environmental conditions. The constructal law allows systems with complex internal flows to be described and understood for a unified view.

  6. Phylogenetic and individual variation in gastropod central pattern generators.

    PubMed

    Sakurai, Akira; Katz, Paul S

    2015-09-01

    Gastropod molluscs provide a unique opportunity to explore the neural basis of rhythmic behaviors because of the accessibility of their nervous systems and the number of species that have been examined. Detailed comparisons of the central pattern generators (CPGs) underlying rhythmic feeding and swimming behaviors highlight the presence and effects of variation in neural circuits both across and within species. The feeding motor pattern of the snail, Lymnaea, is stereotyped, whereas the feeding motor pattern in the sea hare, Aplysia, is variable. However, the Aplysia motor pattern is regularized with operant conditioning or by mimicking learning using the dynamic clamp to change properties of CPG neurons. Swimming evolved repeatedly in marine gastropods. Distinct neural mechanisms underlie dissimilar forms of swimming, with homologous neurons playing different roles. However, even similar swimming behaviors in different species can be produced by distinct neural mechanisms, resulting from different synaptic connectivity of homologous neurons. Within a species, there can be variation in the strength and even valence of synapses, which does not have functional relevance under normal conditions, but can cause some individuals to be more susceptible to lesion of the circuit. This inter- and intra-species variation provides novel insights into CPG function and plasticity. PMID:25837447

  7. Generation of Viable Cell and Biomaterial Patterns by Laser Transfer

    NASA Astrophysics Data System (ADS)

    Ringeisen, Bradley

    2001-03-01

    In order to fabricate and interface biological systems for next generation applications such as biosensors, protein recognition microarrays, and engineered tissues, it is imperative to have a method of accurately and rapidly depositing different active biomaterials in patterns or layered structures. Ideally, the biomaterial structures would also be compatible with many different substrates including technologically relevant platforms such as electronic circuits or various detection devices. We have developed a novel laser-based technique, termed matrix assisted pulsed laser evaporation direct write (MAPLE DW), that is able to direct write patterns and three-dimensional structures of numerous biologically active species ranging from proteins and antibodies to living cells. Specifically, we have shown that MAPLE DW is capable of forming mesoscopic patterns of living prokaryotic cells (E. coli bacteria), living mammalian cells (Chinese hamster ovaries), active proteins (biotinylated bovine serum albumin, horse radish peroxidase), and antibodies specific to a variety of classes of cancer related proteins including intracellular and extracellular matrix proteins, signaling proteins, cell cycle proteins, growth factors, and growth factor receptors. In addition, patterns of viable cells and active biomolecules were deposited on different substrates including metals, semiconductors, nutrient agar, and functionalized glass slides. We will present an explanation of the laser-based transfer mechanism as well as results from our recent efforts to fabricate protein recognition microarrays and tissue-based microfluidic networks.

  8. Evolution of central pattern generators and rhythmic behaviours.

    PubMed

    Katz, Paul S

    2016-01-01

    Comparisons of rhythmic movements and the central pattern generators (CPGs) that control them uncover principles about the evolution of behaviour and neural circuits. Over the course of evolutionary history, gradual evolution of behaviours and their neural circuitry within any lineage of animals has been a predominant occurrence. Small changes in gene regulation can lead to divergence of circuit organization and corresponding changes in behaviour. However, some behavioural divergence has resulted from large-scale rewiring of the neural network. Divergence of CPG circuits has also occurred without a corresponding change in behaviour. When analogous rhythmic behaviours have evolved independently, it has generally been with different neural mechanisms. Repeated evolution of particular rhythmic behaviours has occurred within some lineages due to parallel evolution or latent CPGs. Particular motor pattern generating mechanisms have also evolved independently in separate lineages. The evolution of CPGs and rhythmic behaviours shows that although most behaviours and neural circuits are highly conserved, the nature of the behaviour does not dictate the neural mechanism and that the presence of homologous neural components does not determine the behaviour. This suggests that although behaviour is generated by neural circuits, natural selection can act separately on these two levels of biological organization. PMID:26598733

  9. Organization of mammalian locomotor rhythm and pattern generation.

    PubMed

    McCrea, David A; Rybak, Ilya A

    2008-01-01

    Central pattern generators (CPGs) located in the spinal cord produce the coordinated activation of flexor and extensor motoneurons during locomotion. Previously proposed architectures for the spinal locomotor CPG have included the classical half-center oscillator and the unit burst generator (UBG) comprised of multiple coupled oscillators. We have recently proposed another organization in which a two-level CPG has a common rhythm generator (RG) that controls the operation of the pattern formation (PF) circuitry responsible for motoneuron activation. These architectures are discussed in relation to recent data obtained during fictive locomotion in the decerebrate cat. The data show that the CPG can maintain the period and phase of locomotor oscillations both during spontaneous deletions of motoneuron activity and during sensory stimulation affecting motoneuron activity throughout the limb. The proposed two-level CPG organization has been investigated with a computational model which incorporates interactions between the CPG, spinal circuits and afferent inputs. The model includes interacting populations of spinal interneurons and motoneurons modeled in the Hodgkin-Huxley style. Our simulations demonstrate that a relatively simple CPG with separate RG and PF networks can realistically reproduce many experimental phenomena including spontaneous deletions of motoneuron activity and a variety of effects of afferent stimulation. The model suggests plausible explanations for a number of features of real CPG operation that would be difficult to explain in the framework of the classical single-level CPG organization. Some modeling predictions and directions for further studies of locomotor CPG organization are discussed. PMID:17936363

  10. The generation of vertebral segmental patterning in the chick embryo

    PubMed Central

    Senthinathan, Biruntha; Sousa, Cátia; Tannahill, David; Keynes, Roger

    2012-01-01

    We have carried out a series of experimental manipulations in the chick embryo to assess whether the notochord, neural tube and spinal nerves influence segmental patterning of the vertebral column. Using Pax1 expression in the somite-derived sclerotomes as a marker for segmentation of the developing intervertebral disc, our results exclude such an influence. In contrast to certain teleost species, where the notochord has been shown to generate segmentation of the vertebral bodies (chordacentra), these experiments indicate that segmental patterning of the avian vertebral column arises autonomously in the somite mesoderm. We suggest that in amniotes, the subdivision of each sclerotome into non-miscible anterior and posterior halves plays a critical role in establishing vertebral segmentation, and in maintaining left/right alignment of the developing vertebral elements at the body midline. PMID:22458512

  11. The generation of vertebral segmental patterning in the chick embryo.

    PubMed

    Senthinathan, Biruntha; Sousa, Cátia; Tannahill, David; Keynes, Roger

    2012-06-01

    We have carried out a series of experimental manipulations in the chick embryo to assess whether the notochord, neural tube and spinal nerves influence segmental patterning of the vertebral column. Using Pax1 expression in the somite-derived sclerotomes as a marker for segmentation of the developing intervertebral disc, our results exclude such an influence. In contrast to certain teleost species, where the notochord has been shown to generate segmentation of the vertebral bodies (chordacentra), these experiments indicate that segmental patterning of the avian vertebral column arises autonomously in the somite mesoderm. We suggest that in amniotes, the subdivision of each sclerotome into non-miscible anterior and posterior halves plays a critical role in establishing vertebral segmentation, and in maintaining left/right alignment of the developing vertebral elements at the body midline. PMID:22458512

  12. Torque-stiffness-controlled dynamic walking with central pattern generators.

    PubMed

    Huang, Yan; Vanderborght, Bram; Van Ham, Ronald; Wang, Qining

    2014-12-01

    Walking behavior is modulated by controlling joint torques in most existing passivity-based bipeds. Controlled Passive Walking with adaptable stiffness exhibits controllable natural motions and energy efficient gaits. In this paper, we propose torque-stiffness-controlled dynamic bipedal walking, which extends the concept of Controlled Passive Walking by introducing structured control parameters and a bio-inspired control method with central pattern generators. The proposed walking paradigm is beneficial in clarifying the respective effects of the external actuation and the internal natural dynamics. We present a seven-link biped model to validate the presented walking. Effects of joint torque and joint stiffness on gait selection, walking performance and walking pattern transitions are studied in simulations. The work in this paper develops a new solution of motion control of bipedal robots with adaptable stiffness and provides insights of efficient and sophisticated walking gaits of humans. PMID:25128320

  13. Distinct EEG seizure patterns reflect different seizure generation mechanisms.

    PubMed

    Salami, Pariya; Lévesque, Maxime; Gotman, Jean; Avoli, Massimo

    2015-04-01

    Low-voltage fast (LVF)- and hypersynchronous (HYP)-seizure onset patterns can be recognized in the EEG of epileptic animals and patients with temporal lobe epilepsy. Ripples (80-200 Hz) and fast ripples (250-500 Hz) have been linked to each pattern, with ripples predominating during LVF seizures and fast ripples predominating during HYP seizures in the rat pilocarpine model. This evidence led us to hypothesize that these two seizure-onset patterns reflect the contribution of neural networks with distinct transmitter signaling characteristics. Here, we tested this hypothesis by analyzing the seizure activity induced with the K(+) channel blocker 4-aminopyridine (4AP, 4-5 mg/kg ip), which enhances both glutamatergic and GABAergic transmission, or the GABAA receptor antagonist picrotoxin (3-5 mg/kg ip); rats were implanted with electrodes in the hippocampus, the entorhinal cortex, and the subiculum. We found that LVF onset occurred in 82% of 4AP-induced seizures whereas seizures after picrotoxin were always HYP. In addition, high-frequency oscillation analysis revealed that 4AP-induced LVF seizures were associated with higher ripple rates compared with fast ripples (P < 0.05), whereas picrotoxin-induced seizures contained higher rates of fast ripples compared with ripples (P < 0.05). These results support the hypothesis that two distinct patterns of seizure onset result from different pathophysiological mechanisms. PMID:25652916

  14. A Hormone-Activated Central Pattern Generator For Courtship

    PubMed Central

    Hamilton, M. Sarhas; Huang, Tracy; Kristan, William B.; French, Kathleen A.

    2010-01-01

    Summary Background Medicinal leeches (Hirudo spp.) are simultaneous hermaphrodites. Mating occurs after a stereotyped twisting and oral exploration that result in the alignment of the male and/or female gonopores of one leech with the complementary gonopores of a partner. The neural basis of this behavior is presently unknown and currently impossible to study directly because electrophysiological recording techniques disrupt the behavior. Results Here we report that (Arg8)-conopressin G and two other members of the oxytocin/vasopressin family of peptide hormones induce in Hirudo verbana a sequence of behaviors that closely mimic elements of spontaneous reproductive behavior. Through a series of progressively more reduced preparations, we show that one of these behaviors, a stereotyped twisting that is instrumental to aligning gonopores in preparation for copulation, is the product of a central pattern generator that consists of oscillators in ganglia M5 and M6 (the ganglia in the reproductive segments of the leech), and also in ganglion M4, which was not previously known to play a role in reproductive behavior. We find that the behavior is periodic, with a remarkably long cycle period of around five minutes, placing it among the slowest behavioral rhythms (other than diurnal and annual rhythms) yet described. Conclusion These results establish the leech as a new model system for studying aspects of the neuronal basis of reproductive behavior. Highlights Oxytocin/vasopressin homologues induce pre-copulatory movements in a leech. These movements are generated by a central pattern generator. Segmental ganglia M4, M5, and M6 can each generate fictive behavior in isolation. PMID:20226670

  15. Sequentially firing neurons confer flexible timing in neural pattern generators

    SciTech Connect

    Urban, Alexander; Ermentrout, Bard

    2011-05-15

    Neuronal networks exhibit a variety of complex spatiotemporal patterns that include sequential activity, synchrony, and wavelike dynamics. Inhibition is the primary means through which such patterns are implemented. This behavior is dependent on both the intrinsic dynamics of the individual neurons as well as the connectivity patterns. Many neural circuits consist of networks of smaller subcircuits (motifs) that are coupled together to form the larger system. In this paper, we consider a particularly simple motif, comprising purely inhibitory interactions, which generates sequential periodic dynamics. We first describe the dynamics of the single motif both for general balanced coupling (all cells receive the same number and strength of inputs) and then for a specific class of balanced networks: circulant systems. We couple these motifs together to form larger networks. We use the theory of weak coupling to derive phase models which, themselves, have a certain structure and symmetry. We show that this structure endows the coupled system with the ability to produce arbitrary timing relationships between symmetrically coupled motifs and that the phase relationships are robust over a wide range of frequencies. The theory is applicable to many other systems in biology and physics.

  16. Central Pattern Generator for Locomotion: Anatomical, Physiological, and Pathophysiological Considerations

    PubMed Central

    Guertin, Pierre A.

    2013-01-01

    This article provides a perspective on major innovations over the past century in research on the spinal cord and, specifically, on specialized spinal circuits involved in the control of rhythmic locomotor pattern generation and modulation. Pioneers such as Charles Sherrington and Thomas Graham Brown have conducted experiments in the early twentieth century that changed our views of the neural control of locomotion. Their seminal work supported subsequently by several decades of evidence has led to the conclusion that walking, flying, and swimming are largely controlled by a network of spinal neurons generally referred to as the central pattern generator (CPG) for locomotion. It has been subsequently demonstrated across all vertebrate species examined, from lampreys to humans, that this CPG is capable, under some conditions, to self-produce, even in absence of descending or peripheral inputs, basic rhythmic, and coordinated locomotor movements. Recent evidence suggests, in turn, that plasticity changes of some CPG elements may contribute to the development of specific pathophysiological conditions associated with impaired locomotion or spontaneous locomotor-like movements. This article constitutes a comprehensive review summarizing key findings on the CPG as well as on its potential role in Restless Leg Syndrome, Periodic Leg Movement, and Alternating Leg Muscle Activation. Special attention will be paid to the role of the CPG in a recently identified, and uniquely different neurological disorder, called the Uner Tan Syndrome. PMID:23403923

  17. Radiation Pattern for a Multiple-Element HFGW Generator

    NASA Astrophysics Data System (ADS)

    Baker, Robert M. L.; Black, Christine Stacy

    2009-03-01

    We calculate the values for the High-Frequency Gravitational Wave (HFGW) radiation pattern for a multiple-element HFGW generator in the "far field," that is the field many wavelengths away from the generator. We extend-Baker, Davis and Woods (2005) for a single GW-emission pair to include an in-phase, linear array of N such pairs as discussed in Baker, Stephenson and Li (2008). We calculate new values for the variable K in Baker, Davis and Woods (2005) by decreasing the integration interval of ? from 10° to 1°. This provides us with a K value of increased accuracy. The improved K has a value of 7.6×10-7 deg-2 and is used to find the power intensity, I(?), of a single GW source in terms of watts per square degree over the radiation-pattern cap The ? half-power-point angle for a single GW-emission pair at their mid-way-point focus is also recalculated and found to be 47.5°. We utilize the result of Romero and Dehnen (1981) and Dehnen and Romero (2003) for an increase in HFGW flux (in a linear array of N in-phase radiation elements) proportional to N2. This result is employed to compute the half-power-point angle, idealized radiation cap area and the HFGW flux/power-of-a-single-radiation-element at a distance of several wavelengths away, for example one meter from the end of a linear and a double-helical array in Wm-2 as a function of N. The notional picture shown of an idealized needle-like radiation beam is in the far field. It is described at a distance far enough from the generator that it is beyond the conventional diffraction limit of a beam's radiation-pattern cap area. It is found that the HFGW flux calculated is small, but that the Li-Baker detector may be capable of sensing the HFGWs generated in a laboratory setting.

  18. Airborne radar in-flight antenna pattern testing

    SciTech Connect

    Tang, C.H.

    1994-12-31

    This paper discusses the operation, the accuracy considerations, and the measurement process of an in-flight radar antenna pattern measurement. The in-flight tests performed for the Joint STARS multifunction airborne radar are summarized.

  19. Neural Patterns of the Implicit Association Test

    PubMed Central

    Healy, Graham F.; Boran, Lorraine; Smeaton, Alan F.

    2015-01-01

    The Implicit Association Test (IAT) is a reaction time based categorization task that measures the differential associative strength between bipolar targets and evaluative attribute concepts as an approach to indexing implicit beliefs or biases. An open question exists as to what exactly the IAT measures, and here EEG (Electroencephalography) has been used to investigate the time course of ERPs (Event-related Potential) indices and implicated brain regions in the IAT. IAT-EEG research identifies a number of early (250–450 ms) negative ERPs indexing early-(pre-response) processing stages of the IAT. ERP activity in this time range is known to index processes related to cognitive control and semantic processing. A central focus of these efforts has been to use IAT-ERPs to delineate the implicit and explicit factors contributing to measured IAT effects. Increasing evidence indicates that cognitive control (and related top-down modulation of attention/perceptual processing) may be components in the effective measurement of IAT effects, as factors such as physical setting or task instruction can change an IAT measurement. In this study we further implicate the role of proactive cognitive control and top-down modulation of attention/perceptual processing in the IAT-EEG. We find statistically significant relationships between D-score (a reaction-time based measure of the IAT-effect) and early ERP-time windows, indicating where more rapid word categorizations driving the IAT effect are present, they are at least partly explainable by neural activity not significantly correlated with the IAT measurement itself. Using LORETA, we identify a number of brain regions driving these ERP-IAT relationships notably involving left-temporal, insular, cingulate, medial frontal and parietal cortex in time regions corresponding to the N2- and P3-related activity. The identified brain regions involved with reduced reaction times on congruent blocks coincide with those of previous studies. PMID:26635570

  20. A test pattern identification algorithm and its application to CINRAD/SA(B) data

    NASA Astrophysics Data System (ADS)

    Jiang, Yuan; Liu, Liping

    2014-03-01

    A variety of faulty radar echoes may cause serious problems with radar data applications, especially radar data assimilation and quantitative precipitation estimates. In this study, "test pattern" caused by test signal or radar hardware failures in CINRAD (China New Generation Weather Radar) SA and SB radar operational observations are investigated. In order to distinguish the test pattern from other types of radar echoes, such as precipitation, clear air and other non-meteorological echoes, five feature parameters including the effective reflectivity data percentage ( R Z), velocity RF (range folding) data percentage ( R RF), missing velocity data percentage ( R M), averaged along-azimuth reflectivity fluctuation and averaged along-beam reflectivity fluctuation are proposed. Based on the fuzzy logic method, a test pattern identification algorithm is developed, and the statistical results from all the different kinds of radar echoes indicate the performance of the algorithm. Analysis of two typical cases with heavy precipitation echoes located inside the test pattern are performed. The statistical results show that the test pattern identification algorithm performs well, since the test pattern is recognized in most cases. Besides, the algorithm can effectively remove the test pattern signal and retain strong precipitation echoes in heavy rainfall events.

  1. Sexually differentiated central pattern generators in Xenopus laevis

    PubMed Central

    Zornik, Erik; Yamaguchi, Ayako

    2008-01-01

    Understanding the neural mechanisms that underlie the function of central pattern generators (CPGs) presents a formidable challenge requiring sophisticated tools and well-chosen model systems. In this article, we describe recent work on vocalizations of the African clawed frog Xenopus laevis. These behaviors are driven by sexually differentiated CPGs and are exceptionally well suited to this objective. In particular, a simplified mechanism of vocal production (independent of respiratory musculature) allows straightforward interpretations of nerve activity with respect to behavior. Furthermore, the development of a fictively vocalizing isolated brain, together with the finding of rapid androgen-induced masculinization of female vocalizations, provides an invaluable tool for determining how new behaviors arise from existing circuits. PMID:18471902

  2. Generation of Earth's First-Order Biodiversity Pattern

    NASA Astrophysics Data System (ADS)

    Krug, Andrew Z.; Jablonski, David; Valentine, James W.; Roy, Kaustuv

    2009-02-01

    The first-order biodiversity pattern on Earth today and at least as far back as the Paleozoic is the latitudinal diversity gradient (LDG), a decrease in richness of species and higher taxa from the equator to the poles. LDGs are produced by geographic trends in origination, extinction, and dispersal over evolutionary timescales, so that analyses of static patterns will be insufficient to reveal underlying processes. The fossil record of marine bivalve genera, a model system for the analysis of biodiversity dynamics over large temporal and spatial scales, shows that an origination and range-expansion gradient plays a major role in generating the LDG. Peak origination rates and peak diversities fall within the tropics, with range expansion out of the tropics the predominant spatial dynamic thereafter. The origination-diversity link occurs even in a "contrarian" group whose diversity peaks at midlatitudes, an exception proving the rule that spatial variations in origination are key to latitudinal diversity patterns. Extinction rates are lower in polar latitudes (?60°) than in temperate zones and thus cannot create the observed gradient alone. They may, however, help to explain why origination and immigration are evidently damped in higher latitudes. We suggest that species require more resources in higher latitudes, for the seasonality of primary productivity increases by more than an order of magnitude from equatorial to polar regions. Higher-latitude species are generalists that, unlike potential immigrants, are adapted to garner the large share of resources required for incumbency in those regions. When resources are opened up by extinctions, lineages spread chiefly poleward and chiefly through speciation.

  3. Two-stage Turing model for generating pigment patterns on the leopard and the jaguar

    NASA Astrophysics Data System (ADS)

    Liu, R. T.; Liaw, S. S.; Maini, P. K.

    2006-07-01

    Based on the results of phylogenetic analysis, which showed that flecks are the primitive pattern of the felid family and all other patterns including rosettes and blotches develop from it, we construct a Turing reaction-diffusion model which generates spot patterns initially. Starting from this spotted pattern, we successfully generate patterns of adult leopards and jaguars by tuning parameters of the model in the subsequent phase of patterning.

  4. Two-stage Turing model for generating pigment patterns on the leopard and the jaguar.

    PubMed

    Liu, R T; Liaw, S S; Maini, P K

    2006-07-01

    Based on the results of phylogenetic analysis, which showed that flecks are the primitive pattern of the felid family and all other patterns including rosettes and blotches develop from it, we construct a Turing reaction-diffusion model which generates spot patterns initially. Starting from this spotted pattern, we successfully generate patterns of adult leopards and jaguars by tuning parameters of the model in the subsequent phase of patterning. PMID:16907134

  5. Optimal Test Design with Rule-Based Item Generation

    ERIC Educational Resources Information Center

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

    2013-01-01

    Optimal test-design methods are applied to rule-based item generation. Three different cases of automated test design are presented: (a) test assembly from a pool of pregenerated, calibrated items; (b) test generation on the fly from a pool of calibrated item families; and (c) test generation on the fly directly from calibrated features defining…

  6. Optimal Test Design with Rule-Based Item Generation

    ERIC Educational Resources Information Center

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

    2013-01-01

    Optimal test-design methods are applied to rule-based item generation. Three different cases of automated test design are presented: (a) test assembly from a pool of pregenerated, calibrated items; (b) test generation on the fly from a pool of calibrated item families; and (c) test generation on the fly directly from calibrated features defining…

  7. Generational Patterns in Mexican Americans' Academic Performance in an Unwelcoming Political Context

    PubMed Central

    Moosmann, Danyel A. V.; Roosa, Mark W.; Knight, George P.

    2014-01-01

    Research has shown that immigrant students often do better academically than their U.S.-born peers from the same ethnic group but it is unclear whether this pattern holds for Mexican Americans. We examined the academic performance of four generations of Mexican American students from fifth to 10th grade looking for generation differences and explanations for them. Using data from 749 families, we tested a model with fifth grade variables that differed by generation as potential mediators linking student generation to 10th grade academic performance. Results showed that immigrants were academically behind at fifth grade but caught up by seventh. Only economic hardship mediated the long term relationship between student generation and 10th grade academic performance; maternal educational expectations and child language hassles, English usage, discrimination, and mainstream values helped explained the early academic deficit of immigrant children. The results identified potential targets for interventions to improve Mexican American students' academic performance. PMID:24578588

  8. Generational Patterns in Mexican Americans' Academic Performance in an Unwelcoming Political Context.

    PubMed

    Moosmann, Danyel A V; Roosa, Mark W; Knight, George P

    2014-03-01

    Research has shown that immigrant students often do better academically than their U.S.-born peers from the same ethnic group but it is unclear whether this pattern holds for Mexican Americans. We examined the academic performance of four generations of Mexican American students from fifth to 10th grade looking for generation differences and explanations for them. Using data from 749 families, we tested a model with fifth grade variables that differed by generation as potential mediators linking student generation to 10th grade academic performance. Results showed that immigrants were academically behind at fifth grade but caught up by seventh. Only economic hardship mediated the long term relationship between student generation and 10th grade academic performance; maternal educational expectations and child language hassles, English usage, discrimination, and mainstream values helped explained the early academic deficit of immigrant children. The results identified potential targets for interventions to improve Mexican American students' academic performance. PMID:24578588

  9. Validation Testing of Hydrogen Generation Technology

    SciTech Connect

    Smith, Barton; Toops, Todd J

    2007-12-01

    This report describes the results of testing performed by ORNL for Photech Energies, Inc. The objective of the testing was to evaluate the efficacy of Photech's hydrogen generation reactor technology, which produces gaseous hydrogen through electrolysis. Photech provided several prototypes of their proprietary reactor for testing and the ancillary equipment, such as power supplies and electrolyte solutions, required for proper operation of the reactors. ORNL measured the production of hydrogen gas (volumetric flow of hydrogen at atmospheric pressure) as a function of input power and analyzed the composition of the output stream to determine the purity of the hydrogen content. ORNL attempted measurements on two basic versions of the prototype reactors-one version had a clear plastic outer cylinder, while another version had a stainless steel outer cylinder-but was only able to complete measurements on reactors in the plastic version. The problem observed in the stainless steel reactors was that in these reactors most of the hydrogen was produced near the anodes along with oxygen and the mixed gases made it impossible to determine the amount of hydrogen produced. In the plastic reactors the production of hydrogen gas increased monotonically with input power, and the flow rates increased faster at low input powers than they did at higher input powers. The maximum flow rate from the cathode port measured during the tests was 0.85 LPM at an input power of about 1100 W, an electrolyte concentration of 20%. The composition of the flow from the cathode port was primarily hydrogen and water vapor, with some oxygen and trace amounts of carbon dioxide. An operational mode that occurs briefly during certain operating conditions, and is characterized by flashes of light and violent bubbling near the cathode, might be attributable to the combustion of hydrogen and oxygen in the electrolyte solution.

  10. A rule-based software test data generator

    NASA Technical Reports Server (NTRS)

    Deason, William H.; Brown, David B.; Chang, Kai-Hsiung; Cross, James H., II

    1991-01-01

    Rule-based software test data generation is proposed as an alternative to either path/predicate analysis or random data generation. A prototype rule-based test data generator for Ada programs is constructed and compared to a random test data generator. Four Ada procedures are used in the comparison. Approximately 2000 rule-based test cases and 100,000 randomly generated test cases are automatically generated and executed. The success of the two methods is compared using standard coverage metrics. Simple statistical tests showing that even the primitive rule-based test data generation prototype is significantly better than random data generation are performed. This result demonstrates that rule-based test data generation is feasible and shows great promise in assisting test engineers, especially when the rule base is developed further.

  11. HIV Testing Patterns among Urban YMSM of Color

    ERIC Educational Resources Information Center

    Leonard, Noelle R.; Rajan, Sonali; Gwadz, Marya V.; Aregbesola, Temi

    2014-01-01

    The heightened level of risk for HIV infection among Black and Latino young men who have sex with men (YMSM) is driven by multilevel influences. Using cross-sectional data, we examined HIV testing patterns among urban YMSM of color in a high-HIV seroprevalence area (ages 16 to 21 years). Self-reported frequency of testing was high, with 42% of…

  12. HIV Testing Patterns among Urban YMSM of Color

    ERIC Educational Resources Information Center

    Leonard, Noelle R.; Rajan, Sonali; Gwadz, Marya V.; Aregbesola, Temi

    2014-01-01

    The heightened level of risk for HIV infection among Black and Latino young men who have sex with men (YMSM) is driven by multilevel influences. Using cross-sectional data, we examined HIV testing patterns among urban YMSM of color in a high-HIV seroprevalence area (ages 16 to 21 years). Self-reported frequency of testing was high, with 42% of…

  13. Test Generation Algorithm for Fault Detection of Analog Circuits Based on Extreme Learning Machine

    PubMed Central

    Zhou, Jingyu; Tian, Shulin; Yang, Chenglin; Ren, Xuelong

    2014-01-01

    This paper proposes a novel test generation algorithm based on extreme learning machine (ELM), and such algorithm is cost-effective and low-risk for analog device under test (DUT). This method uses test patterns derived from the test generation algorithm to stimulate DUT, and then samples output responses of the DUT for fault classification and detection. The novel ELM-based test generation algorithm proposed in this paper contains mainly three aspects of innovation. Firstly, this algorithm saves time efficiently by classifying response space with ELM. Secondly, this algorithm can avoid reduced test precision efficiently in case of reduction of the number of impulse-response samples. Thirdly, a new process of test signal generator and a test structure in test generation algorithm are presented, and both of them are very simple. Finally, the abovementioned improvement and functioning are confirmed in experiments. PMID:25610458

  14. Caregiving Practice Patterns of Asian, Hispanic, and Non-Hispanic White American Family Caregivers of Older Adults Across Generations.

    PubMed

    Miyawaki, Christina E

    2016-03-01

    This study is a cross-sectional investigation of caregiving practice patterns among Asian, Hispanic and non-Hispanic White American family caregivers of older adults across three immigrant generations. The 2009 California Health Interview Survey (CHIS) dataset was used, and 591 Asian, 989 Hispanic and 6537 non-Hispanic White American caregivers of older adults were selected. First, descriptive analyses of caregivers' characteristics, caregiving situations and practice patterns were examined by racial/ethnic groups and immigrant generations. Practice patterns measured were respite care use, hours and length of caregiving. Three hypotheses on caregiving patterns based on assimilation theory were tested and analyzed using logistic regression and generalized linear models by racial/ethnic groups and generations. Caregiving patterns of non-Hispanic White caregivers supported all three hypotheses regarding respite care use, caregiving hours and caregiving duration, showing less caregiving involvement in later generations. However, Asian and Hispanic counterparts showed mixed results. Third generation Asian and Hispanic caregivers used respite care the least and spent the most caregiving hours per week and had the longest caregiving duration compared to earlier generations. These caregiving patterns revealed underlying cultural values related to filial responsibility, even among later generations of caregivers of color. Findings suggest the importance of considering the cultural values of each racial/ethnic group regardless of generation when working with racially and ethnically diverse populations of family caregivers of older adults. PMID:26810575

  15. Electronic tongue generating continuous recognition patterns for protein analysis.

    PubMed

    Hou, Yanxia; Genua, Maria; Garçon, Laurie-Amandine; Buhot, Arnaud; Calemczuk, Roberto; Bonnaffé, David; Lortat-Jacob, Hugues; Livache, Thierry

    2014-01-01

    In current protocol, a combinatorial approach has been developed to simplify the design and production of sensing materials for the construction of electronic tongues (eT) for protein analysis. By mixing a small number of simple and easily accessible molecules with different physicochemical properties, used as building blocks (BBs), in varying and controlled proportions and allowing the mixtures to self-assemble on the gold surface of a prism, an array of combinatorial surfaces featuring appropriate properties for protein sensing was created. In this way, a great number of cross-reactive receptors can be rapidly and efficiently obtained. By combining such an array of combinatorial cross-reactive receptors (CoCRRs) with an optical detection system such as surface plasmon resonance imaging (SPRi), the obtained eT can monitor the binding events in real-time and generate continuous recognition patterns including 2D continuous evolution profile (CEP) and 3D continuous evolution landscape (CEL) for samples in liquid. Such an eT system is efficient for discrimination of common purified proteins. PMID:25286325

  16. The NIH Toolbox Pattern Comparison Processing Speed Test: Normative Data.

    PubMed

    Carlozzi, Noelle E; Beaumont, Jennifer L; Tulsky, David S; Gershon, Richard C

    2015-08-01

    The NIH Toolbox Pattern Comparison Processing Speed Test was developed to assess processing speed. While initial validation work provides preliminary support for this test in both children and adults, more work is needed to ensure dependability and generalizability. Thus, this replication study examines descriptive data (including age effects), test-retest reliability, and construct validity in n = 4,859 participants ages 3-85 years (matched to 2010 census data). Although the Pattern Comparison was not appropriate for all 3 and 4 years old, by ages 5 and 6, more meaningful scores were apparent. There was evidence for convergent and discriminant validity. There was also a moderate practice effect (i.e., increase of 5.5 points) over a 1-week time frame. Pattern Comparison exhibits a number of strengths: it is appropriate for use across the lifespan (ages 5-85), it is short and easy to administer, and there is support for construct validity. PMID:26025230

  17. Cellular basis for singing motor pattern generation in the field cricket (Gryllus bimaculatus DeGeer)

    PubMed Central

    Schöneich, Stefan; Hedwig, Berthold

    2012-01-01

    The singing behavior of male crickets allows analyzing a central pattern generator (CPG) that was shaped by sexual selection for reliable production of species-specific communication signals. After localizing the essential ganglia for singing in Gryllus bimaculatus, we now studied the calling song CPG at the cellular level. Fictive singing was initiated by pharmacological brain stimulation. The motor pattern underlying syllables and chirps was recorded as alternating spike bursts of wing-opener and wing-closer motoneurons in a truncated wing nerve; it precisely reflected the natural calling song. During fictive singing, we intracellularly recorded and stained interneurons in thoracic and abdominal ganglia and tested their impact on the song pattern by intracellular current injections. We identified three interneurons of the metathoracic and first unfused abdominal ganglion that rhythmically de- and hyperpolarized in phase with the syllable pattern and spiked strictly before the wing-opener motoneurons. Depolarizing current injection in two of these opener interneurons caused additional rhythmic singing activity, which reliably reset the ongoing chirp rhythm. The closely intermeshing arborizations of the singing interneurons revealed the dorsal midline neuropiles of the metathoracic and three most anterior abdominal neuromeres as the anatomical location of singing pattern generation. In the same neuropiles, we also recorded several closer interneurons that rhythmically hyper- and depolarized in the syllable rhythm and spiked strictly before the wing-closer motoneurons. Some of them received pronounced inhibition at the beginning of each chirp. Hyperpolarizing current injection in the dendrite revealed postinhibitory rebound depolarization as one functional mechanism of central pattern generation in singing crickets. PMID:23170234

  18. Neural basis of singing in crickets: central pattern generation in abdominal ganglia

    NASA Astrophysics Data System (ADS)

    Schöneich, Stefan; Hedwig, Berthold

    2011-12-01

    The neural mechanisms underlying cricket singing behavior have been the focus of several studies, but the central pattern generator (CPG) for singing has not been localized conclusively. To test if the abdominal ganglia contribute to the singing motor pattern and to analyze if parts of the singing CPG are located in these ganglia, we systematically truncated the abdominal nerve cord of fictively singing crickets while recording the singing motor pattern from a front-wing nerve. Severing the connectives anywhere between terminal ganglion and abdominal ganglion A3 did not preclude singing, although the motor pattern became more variable and failure-prone as more ganglia were disconnected. Singing terminated immediately and permanently after transecting the connectives between the metathoracic ganglion complex and the first unfused abdominal ganglion A3. The contribution of abdominal ganglia for singing pattern generation was confirmed by intracellular interneuron recordings and current injections. During fictive singing, an ascending interneuron with its soma and dendrite in A3 depolarized rhythmically. It spiked 10 ms before the wing-opener activity and hyperpolarized in phase with the wing-closer activity. Depolarizing current injection elicited rhythmic membrane potential oscillations and spike bursts that elicited additional syllables and reliably reset the ongoing chirp rhythm. Our results disclose that the abdominal ganglion A3 is directly involved in generating the singing motor pattern, whereas the more posterior ganglia seem to provide only stabilizing feedback to the CPG circuit. Localizing the singing CPG in the anterior abdominal neuromeres now allows analyzing its circuitry at the level of identified interneurons in subsequent studies.

  19. 21 CFR 882.1430 - Electroencephalograph test signal generator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Electroencephalograph test signal generator. 882.1430 Section 882.1430 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Electroencephalograph test signal generator. (a) Identification. An electroencephalograph test signal generator is...

  20. 21 CFR 882.1430 - Electroencephalograph test signal generator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Electroencephalograph test signal generator. 882.1430 Section 882.1430 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Electroencephalograph test signal generator. (a) Identification. An electroencephalograph test signal generator is...

  1. 21 CFR 882.1430 - Electroencephalograph test signal generator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Electroencephalograph test signal generator. 882.1430 Section 882.1430 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Electroencephalograph test signal generator. (a) Identification. An electroencephalograph test signal generator is...

  2. 21 CFR 882.1430 - Electroencephalograph test signal generator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Electroencephalograph test signal generator. 882.1430 Section 882.1430 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Electroencephalograph test signal generator. (a) Identification. An electroencephalograph test signal generator is...

  3. 21 CFR 882.1430 - Electroencephalograph test signal generator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electroencephalograph test signal generator. 882.1430 Section 882.1430 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Electroencephalograph test signal generator. (a) Identification. An electroencephalograph test signal generator is...

  4. 40 CFR 53.22 - Generation of test atmospheres.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 6 2014-07-01 2014-07-01 false Generation of test atmospheres. 53.22... Characteristics of Automated Methods for SO2, CO, O3, and NO2 § 53.22 Generation of test atmospheres. (a) Table B-2 to subpart B of part 53 specifies preferred methods for generating test atmospheres and...

  5. 40 CFR 53.22 - Generation of test atmospheres.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 6 2012-07-01 2012-07-01 false Generation of test atmospheres. 53.22... Characteristics of Automated Methods for SO2, CO, O3, and NO2 § 53.22 Generation of test atmospheres. (a) Table B-2 to subpart B of part 53 specifies preferred methods for generating test atmospheres and...

  6. 40 CFR 53.22 - Generation of test atmospheres.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Generation of test atmospheres. 53.22... Characteristics of Automated Methods for SO2, CO, O3, and NO2 § 53.22 Generation of test atmospheres. (a) Table B-2 to subpart B of part 53 specifies preferred methods for generating test atmospheres and...

  7. "MSTGen": Simulated Data Generator for Multistage Testing

    ERIC Educational Resources Information Center

    Han, Kyung T.

    2013-01-01

    Multistage testing, or MST, was developed as an alternative to computerized adaptive testing (CAT) for applications in which it is preferable to administer a test at the level of item sets (i.e., modules). As with CAT, the simulation technique in MST plays a critical role in the development and maintenance of tests. "MSTGen," a new MST…

  8. "MSTGen": Simulated Data Generator for Multistage Testing

    ERIC Educational Resources Information Center

    Han, Kyung T.

    2013-01-01

    Multistage testing, or MST, was developed as an alternative to computerized adaptive testing (CAT) for applications in which it is preferable to administer a test at the level of item sets (i.e., modules). As with CAT, the simulation technique in MST plays a critical role in the development and maintenance of tests. "MSTGen," a new MST…

  9. The Generation of Antiphase Oscillations and Synchrony by a Rebound-Based Vertebrate Central Pattern Generator

    PubMed Central

    Merrison-Hort, Robert; Zhang, Hong-Yan; Borisyuk, Roman

    2014-01-01

    Many neural circuits are capable of generating multiple stereotyped outputs after different sensory inputs or neuromodulation. We have previously identified the central pattern generator (CPG) for Xenopus tadpole swimming that involves antiphase oscillations of activity between the left and right sides. Here we analyze the cellular basis for spontaneous left–right motor synchrony characterized by simultaneous bursting on both sides at twice the swimming frequency. Spontaneous synchrony bouts are rare in most tadpoles, and they instantly emerge from and switch back to swimming, most frequently within the first second after skin stimulation. Analyses show that only neurons that are active during swimming fire action potentials in synchrony, suggesting both output patterns derive from the same neural circuit. The firing of excitatory descending interneurons (dINs) leads that of other types of neurons in synchrony as it does in swimming. During synchrony, the time window between phasic excitation and inhibition is 7.9 ± 1 ms, shorter than that in swimming (41 ± 2.3 ms). The occasional, extra midcycle firing of dINs during swimming may initiate synchrony, and mismatches of timing in the left and right activity can switch synchrony back to swimming. Computer modeling supports these findings by showing that the same neural network, in which reciprocal inhibition mediates rebound firing, can generate both swimming and synchrony without circuit reconfiguration. Modeling also shows that lengthening the time window between phasic excitation and inhibition by increasing dIN synaptic/conduction delay can improve the stability of synchrony. PMID:24760866

  10. Testing the Generation of Jets in Young Stars with ALMA

    NASA Astrophysics Data System (ADS)

    Bacciotti, F.; Podio, L.; Codella, C.; Coffey, D.

    2015-12-01

    Jets are a crucial element in the star formation process, as they are thought to remove the excess angular momentum from the system. A firm detection of jet rotation could lend support to this statement. Jet rotation studies, however, are hindered by the requirement of simultaneous high spatial and spectral resolution, and as a matter of fact, the rotation interpretation is still debated. Soon, however, the improved spatial resolution of ALMA will allow us to firmly establish rotation patterns. At the same time the new ALMA polarimetric capabilities will permit the determination of the magnetic configuration in the system. The ALMA combined search for rotation properties and magnetic fields will be a powerful test of the proposed jet generation mechanisms.

  11. Quantum lithography with classical light: Generation of arbitrary patterns

    SciTech Connect

    Sun Qingqing; Zubairy, M. Suhail; Hemmer, Philip R.

    2007-06-15

    Based on our previous scheme [Hemmer et al., Phys. Rev. Lett. 96, 163603 (2006)] we show the procedures to obtain any one- or two-dimensional pattern by multiple exposures. A key modification to the resonance condition is made to achieve subwavelength pattern resolution. The level separation of the substrate does not pose an upper limit to the frequency summation. So the fundamental frequency can be high and the number of Fourier terms can be large, making our scheme very suitable for subwavelength arbitrary patterns.

  12. Computer program for automatic generation of BWR control rod patterns

    SciTech Connect

    Taner, M.S.; Levine, S.H.; Hsia, M.Y. )

    1990-01-01

    A computer program named OCTOPUS has been developed to automatically determine a control rod pattern that approximates some desired target power distribution as closely as possible without violating any thermal safety or reactor criticality constraints. The program OCTOPUS performs a semi-optimization task based on the method of approximation programming (MAP) to develop control rod patterns. The SIMULATE-E code is used to determine the nucleonic characteristics of the reactor core state.

  13. A Compartmental Lateral Inhibition System to Generate Contrasting Patterns

    PubMed Central

    Rufino Ferreira, Ana S.; Hsia, Justin; Arcak, Murat

    2015-01-01

    We propose a lateral inhibition system and analyze contrasting patterns of gene expression. The system consists of a set of compartments interconnected by channels. Each compartment contains a colony of cells that produce diffusible molecules to be detected by the neighboring colonies. Each cell is equipped with an inhibitory circuit that reduces its production when the detected signal is sufficiently strong. We characterize the parameter range in which steady-state patterns emerge. PMID:26665158

  14. The Full Function Test Explosive Generator

    SciTech Connect

    Reisman, D B; Javedani, J B; Griffith, L V; Ellsworth, G F; Kuklo, R M; Goerz, D A; White, A D; Tallerico, L J; Gidding, D A; Murphy, M J; Chase, J B

    2009-12-13

    We have conducted three tests of a new pulsed power device called the Full Function Test (FFT). These tests represented the culmination of an effort to establish a high energy pulsed power capability based on high explosive pulsed power (HEPP) technology. This involved an extensive computational modeling, engineering, fabrication, and fielding effort. The experiments were highly successful and a new US record for magnetic energy was obtained.

  15. Note: The full function test explosive generator

    NASA Astrophysics Data System (ADS)

    Reisman, D. B.; Javedani, J. B.; Griffith, L. V.; Ellsworth, G. F.; Kuklo, R. M.; Goerz, D. A.; White, A. D.; Tallerico, L. J.; Gidding, D. A.; Murphy, M. J.; Chase, J. B.

    2010-03-01

    We have conducted three tests of a new pulsed power device called the full function test. These tests represented the culmination of an effort to establish a high energy pulsed power capability based on high explosive pulsed power (HEPP) technology. This involved an extensive computational modeling, engineering, fabrication, and fielding effort. The experiments were highly successful and a new U.S. record for magnetic energy was obtained.

  16. Generation of Crystal-Structure Transverse Patterns via a Self-Frequency-Doubling Laser

    PubMed Central

    Yu, Haohai; Zhang, Huaijin; Wang, Yicheng; Wang, Zhengping; Wang, Jiyang; Petrov, V.

    2013-01-01

    Two-dimensional (2D) visible crystal-structure patterns analogous to the quantum harmonic oscillator (QHO) have been experimentally observed in the near- and far-fields of a self-frequency-doubling (SFD) microchip laser. Different with the fundamental modes, the localization of the SFD light is changed with the propagation. Calculation based on Hermite-Gaussian (HG) functions and second harmonic generation theory reproduces well the patterns both in the near- and far-field which correspond to the intensity distribution in coordinate and momentum spaces, respectively. Considering the analogy of wave functions of the transverse HG mode and 2D harmonic oscillator, we propose that the simple monolithic SFD lasers can be used for developing of new materials and devices and testing 2D quantum mechanical theories. PMID:23336067

  17. Generation pattern of sulfur containing gases from anaerobically digested sludge cakes.

    PubMed

    Novak, John T; Adams, Gregory; Chen, Yen-Chih; Erdal, Zeynep; Forbes, Robert H; Glindemann, Dietmar; Hargreaves, J Ronald; Hentz, Lawrence; Higgins, Matthew J; Murthy, Sudhir N; Witherspoon, Jay

    2006-08-01

    Eleven dewatered sludge cakes collected from anaerobic digesters at different treatment plants were evaluated for the amount, type, and pattern of odorous gas production. All but one of the sludge cakes were from mesophilic anaerobic digesters. One was from a thermophilic digester. The pattern and quantities of sulfur gases were found to be unique for each of the samples with regard to the products produced, magnitude, and subsequent decline. The main odor-causing chemicals were volatile sulfur compounds, which included hydrogen sulfide, methanethiol, and dimethyl sulfide. Volatile sulfur compound production peaked in 3 to 8 days and then declined. The decline was a result of conversion of organic sulfur compounds to sulfide. In one side-by-side test, a high-solids centrifuge cake generated more odorous compounds than the low-solids centrifuge cake. The data show that anaerobic digestion does not eliminate the odor potential of anaerobically digested dewatered cakes. PMID:17059135

  18. Adding Test Generation to the Teaching Machine

    ERIC Educational Resources Information Center

    Bruce-Lockhart, Michael; Norvell, Theodore; Crescenzi, Pierluigi

    2009-01-01

    We propose an extension of the Teaching Machine project, called Quiz Generator, that allows instructors to produce assessment quizzes in the field of algorithm and data structures quite easily. This extension makes use of visualization techniques and is based on new features of the Teaching Machine that allow third-party visualizers to be added as…

  19. Adding Test Generation to the Teaching Machine

    ERIC Educational Resources Information Center

    Bruce-Lockhart, Michael; Norvell, Theodore; Crescenzi, Pierluigi

    2009-01-01

    We propose an extension of the Teaching Machine project, called Quiz Generator, that allows instructors to produce assessment quizzes in the field of algorithm and data structures quite easily. This extension makes use of visualization techniques and is based on new features of the Teaching Machine that allow third-party visualizers to be added as…

  20. Techniques for testing the quality of parallel pseudorandom number generators

    SciTech Connect

    Cuccaro, S.A.; Mascagni, M.; Pryor, D.V.

    1995-12-01

    Ensuring that pseudorandom number generators have good randomness properties is more complicated in a multiprocessor implementation than in the uniprocessor case. We discuss simple extensions of uniprocessor testing for SIMD parallel streams, and develop in detail a repeatability test for the SPMD paradigm. Examples of the application of these tests to an additive tagged-Fibonacci generator are also given.

  1. Octopamine-containing (OC) interneurons enhance central pattern generator activity in sucrose-induced feeding in the snail Lymnaea.

    PubMed

    Vehovszky, Agnes; Szabó, Henriette; Elliott, Christopher J H

    2004-10-01

    In the pond snail Lymnaea stagnalis octopamine-containing (OC) interneurons trigger and reconfigure the feeding pattern in isolated CNS by excitation of the central pattern generator. In semi-intact (lip-mouth-CNS) preparations, this central pattern generator is activated by chemosensory inputs. We now test if sucrose application to the lips activates the OC neurons independently of the rest of the feeding central pattern generator, or if the OC interneuron is activated by inputs from the feeding network. In 66% of experiments, sucrose stimulated feeding rhythms and OC interneurons received regular synaptic inputs. Only rarely (14%) did the OC interneuron fire action potentials, proving that firing of OC interneurons is not necessary for the sucrose-induced feeding. Prestimulation of OC neurons increased the intensity and duration of the feeding rhythm evoked by subsequent sucrose presentations. One micromolar octopamine in the CNS bath mimicked the effect of OC interneuron stimulation, enhancing the feeding response when sucrose is applied to the lips. We conclude that the modulatory OC neurons are not independently excited by chemosensory inputs to the lips, but rather from the buccal central pattern generator network. However, when OC neurons fire, they release modulatory octopamine, which provides a positive feedback to the network to enhance the sucrose-activated central pattern generator rhythm. PMID:15316729

  2. Test-Aerosol Generator For Calibrating Particle Counters

    NASA Technical Reports Server (NTRS)

    Mogan, Paul A.; Adams, Alois J.; Schwindt, Christian J.; Hodge, Timothy R.; Mallow, Tim J.; Duong, Anh A.; Bukauskas, Vyto V.

    1996-01-01

    Apparatus generates clean, stable aerosol stream for use in testing and calibrating laser-based aerosol-particle counter. Size and concentration of aerosol particles controlled to ensure accurate calibration. Cheap, widely available medical nebulizers used to generate aerosols.

  3. SSME seal test program: Test results for hole-pattern damper seals

    NASA Technical Reports Server (NTRS)

    Childs, D. W.

    1985-01-01

    The results consisting of direct and transverse force coefficients are presented for thirteen, hole-pattern, damper-seal configurations. The designation damper seal refers to a seal which uses a deliberately roughened stator nd smooth rotor, to increase the net damping force developed by a seal. The designation hole-pattern refers to a stator roughness pattern which is developed by a pattern of round holes while are milled into the stator. All seals tested use the same smooth rotor and have the same constant minimum clearance. The seal tests examined the following major design options: (1) hole-area density, i.e., the proportion of stator surface area consumed by holes; and (2) hole depth, particularly the ratio of hole depth to minimum clearance. In addition, limited data were taken to examine the influence of in-line versus staggered hole patterns and flat-bottomed versus spherical-bottomed holes.

  4. Object-adapted inverse pattern projection: generation, evaluation, and applications

    NASA Astrophysics Data System (ADS)

    Bothe, Thorsten; Li, Wansong; von Kopylow, Christoph; Juptner, Werner P.

    2003-05-01

    Fast and robust 3D quality control as well as fast deformation measurement is of particular importance for industrial inspection. Additionally a direct response about measured properties is desired. Therefore, robust optical techniques are needed which use as few images as possible for measurement and visualize results in an efficient way. One promising technique for this aim is the inverse pattern projection which has the following advantages: The technique codes the information of a preceding measurement into the projected inverse pattern. Thus, it is possible to do differential measurements using only one camera frame for each state. Additionally, the results are optimized straight fringes for sampling which are independent of the object curvature. The ability to use any image for inverse projection enables the use for augmented reality, i.e. any properties can be visualized directly on the object's surface which makes inspections easier than with use of a separated indicating device. The hardware needs are low as just a programmable projector and a standard camera are necessary. The basic idea of inverse pattern projection, necessary algorithms ane found optimizations are demonstrated, roughly. Evaluation techniques were found to preserve a high quality phase measurement under imperfect conditions. The different application fields can be sorted out by the type of pattern used for inverse projection. We select two main topics for presentation. One is the incremental (one image per state) deformation measurement which is a promising technique for high speed deformation measurements. A video series of a wavering flag with projected inverse pattern was evaluated to show the complete deformation series. The other application is the optical feature marking (augmented reality) that allows to map any measured result directly onto the object under investigation. The general ability to straighten any kind of information on 3D surfaces is shown while preserving an exact mapping of camera image and object parts. In many cases this supersedes an additional monitor to view results and allows an operator to investigate results on the object, directly.

  5. SSME seal test program: Test results for smooth, hole-pattern and helically-grooved stators

    NASA Technical Reports Server (NTRS)

    Childs, Dara W.

    1987-01-01

    All of the listed seals were tested in a liquid Halon test facility at high Reynolds numbers. In addition, a helically-grooved-stator seal was tested in an air seal facility. An analysis of the test results with comparisons to theoretical predictions supports the following conclusions: (1) For small seals, the Hirs' friction-factor model is more restricted than had been thought; (2) For smooth seals, predictions of stiffness and damping improve markedly as the radical clearance is reduced; (3) Friction-factor data for hole-pattern-seal stators frequently deviates from the Hirs model; (4) Predictions of stiffness and damping coefficients for hole-pattern-stator seals is generally reasonable; (5) Tests for the hole-pattern stators at reduced clearances show no clear optimum for hole-pattern seals with respect to either hole-area ratio or hole depth to minimum clearance ratios; (6) Tests of these hole-pattern stators show no significant advantage in net damping over smooth seals; (7) Tests of helically-grooved seal stators in Halon show reasonable agreement between theory and prediction for leakage and direct stiffness but poor agreement for the net damping coefficient.

  6. HIV Testing Patterns Among Urban YMSM of Color

    PubMed Central

    Leonard, Noelle R.; Ragan, Sonali; Gwadz, Marya V.; Aregbesola, Temi

    2015-01-01

    The heightened level of risk for HIV infection among African-American and Latino young men who have sex with men (YMSM) is driven by multi-level influences. Using cross-sectional data, we examined HIV testing patterns among urban YMSM of color in a high HIV sero-prevalence area (ages 16 to 21 years). Self-reported frequency of testing was high with 42% of youth reporting testing at a greater frequency than recommended guidelines. There were no differences between less frequent and high frequent testers on sexual risk behaviors. Most (80%) youth cited reassurance of HIV-negative status as a reason for testing. Further, over half of the sample reported numerous other reasons for HIV testing, which spanned individual, partner, social, and structural levels of influence. Approximately half of respondents indicated that peers, family members, and counselors influenced their motivation to get tested. Of concern, youths’ first HIV test occurred approximately two years after their first sexual experience with another male. These results indicate the need to consider developmental issues as well as for comprehensive, multi-level efforts to ensure that YMSM of color test at the CDC-recommended frequency, but not less than this or too frequently. PMID:24973260

  7. F-1 Engine Gas Generator Testing - Duration: 110 seconds.

    NASA Video Gallery

    The gas generator from an F-1 engine is test-fired at the Marshall Space Flight Center in Huntsville, Ala., on Jan. 24, 2013. Data from the 30 second test will be used in the development of advance...

  8. Reflective electron beam lithography: lithography results using CMOS controlled digital pattern generator chip

    NASA Astrophysics Data System (ADS)

    Gubiotti, Thomas; Sun, Jeff Fuge; Freed, Regina; Kidwingira, Francoise; Yang, Jason; Bevis, Chris; Carroll, Allen; Brodie, Alan; Tong, William M.; Lin, Shy-Jay; Wang, Wen-Chuan; Haspeslagh, Luc; Vereecke, Bart

    2013-03-01

    Maskless electron beam lithography can potentially extend semiconductor manufacturing to the 10 nm logic (16 nm half pitch) technology node and beyond. KLA-Tencor is developing Reflective Electron Beam Lithography (REBL) technology targeting high-volume 10 nm logic node performance. REBL uses a novel multi-column wafer writing system combined with an advanced stage architecture to enable the throughput and resolution required for a NGL system. Using a CMOS Digital Pattern Generator (DPG) chip with over one million microlenses, the system is capable of maskless printing of arbitrary patterns with pixel redundancy and pixel-by-pixel grayscaling at the wafer. Electrons are generated in a flood beam via a thermionic cathode at 50-100 keV and decelerated to illuminate the DPG chip. The DPG-modulated electron beam is then reaccelerated and demagnified 80-100x onto the wafer to be printed. Previously, KLA-Tencor reported on the development progress of the REBL tool for maskless lithography at and below the 10 nm logic technology node. Since that time, the REBL team has made good progress towards developing the REBL system and DPG for direct write lithography. REBL has been successful in manufacturing a CMOS controlled DPG chip with a stable charge drain coating and with all segments functioning. This DPG chip consists of an array of over one million electrostatic lenslets that can be switched on or off via CMOS voltages to pattern the flood electron beam. Testing has proven the validity of the design with regards to lenslet performance, contrast, lifetime, and pattern scrolling. This chip has been used in the REBL demonstration platform system for lithography on a moving stage in both PMMA and chemically amplified resist. Direct imaging of the aerial image has also been performed by magnifying the pattern at the wafer plane via a mag stack onto a YAG imaging screen. This paper will discuss the chip design improvements and new charge drain coating that have resulted in a functional DPG chip and will evaluate the current chip performance on the REBL system. Print results for line/space and device test patterns at the 100nm node will be presented.

  9. Effect of HF heating array directivity pattern on the frequency response of generated ELF VLF

    NASA Astrophysics Data System (ADS)

    Carroll, K. J.; Ferraro, A. J.; Long, B.; Lunnen, R. J.; Lee, H. S.; Allshouse, R.

    1983-01-01

    Directivity patterns at 3.17 MHz and 5.1 MHz are calculated for the HF antenna array at the high power HF heating facility. The pattern was calculated using pattern multiplication and method of moment techniques. The calculated pattern is shown to be a good approximation to an experimentally measured pattern in one plane of the array. A simple model was used to approximate the effect of the pattern on the frequency response of ELF/VLF signals generated by the HF heating. The frequency response was determined at two ELF/VLF receiver sites. Results show that ELF/VLF generated by side lobes of the HF pattern have sufficient strength to create a ELF/VLF interference pattern at receiving locations.

  10. 32 nm imprint masks using variable shape beam pattern generators

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; Schmid, Gerard; Stacey, Nick; Perez, Joseph; Maltabes, John; Resnick, Douglas J.; Yeo, Jeongho; Kim, Hoyeon; Eynon, Ben

    2008-05-01

    Imprint lithography has been included on the ITRS Lithography Roadmap at the 32, 22 and 16 nm nodes. Step and Flash Imprint Lithography (S-FIL ®) is a unique method that has been designed from the beginning to enable precise overlay for creating multilevel devices. A photocurable low viscosity monomer is dispensed dropwise to meet the pattern density requirements of the device, thus enabling imprint patterning with a uniform residual layer across a field and across entire wafers. Further, S-FIL provides sub-100 nm feature resolution without the significant expense of multi-element, high quality projection optics or advanced illumination sources. However, since the technology is 1X, it is critical to address the infrastructure associated with the fabrication of templates. For sub-32 nm device manufacturing, one of the major technical challenges remains the fabrication of full-field 1x templates with commercially viable write times. Recent progress in the writing of sub-40 nm patterns using commercial variable shape e-beam tools and non-chemically amplified resists has demonstrated a very promising route to realizing these objectives, and in doing so, has considerably strengthened imprint lithography as a competitive manufacturing technology for the sub 32nm node. Here we report the first imprinting results from sub-40 nm full-field patterns, using Samsung's current flash memory production device design. The fabrication of the template is discussed and the resulting critical dimension control and uniformity are discussed, along with image placement results. The imprinting results are described in terms of CD uniformity, etch results, and overlay.

  11. Next-Generation Antimicrobial Susceptibility Testing

    PubMed Central

    Dunne, W. Michael

    2013-01-01

    Antimicrobial resistance has emerged as one of the most-significant health care problems of the new millennium, and the clinical microbiology laboratory plays a central role in optimizing the therapeutic management of patients with infection. This minireview explores the potential value of innovative methods for antimicrobial susceptibility testing of microorganisms that could provide valuable alternatives to existing methodologies in the very near future. PMID:23486706

  12. 40 CFR 86.1333 - Transient test cycle generation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... The generation of the maximum torque curve is described in 40 CFR part 1065. (b) Example of the...: ER28AP14.006 Where: Max Test Speed = the maximum test speed as calculated in 40 CFR part 1065. (ii) For Otto-cycle engines: ER28AP14.007 Where: Max Test Speed = the maximum test speed as calculated in 40...

  13. Converging Laser Generated Ultrasonic Waves using Annular Patterns Irradiation

    NASA Astrophysics Data System (ADS)

    Zamiri, S.; Reitinger, B.; Bauer, S.; Burgholzer, P.

    2014-06-01

    We report on a contactless method to focus laser generated bulk and surface ultrasound waves in the thermo-elastic coupling mode by annular shaped illumination. By using a spatial light modulator (SLM) the beam profile of a pulsed picoseconds laser was shaped to annular forms flexibly and further rings with a thickness of 50 μm and a generation energy as low as 2 mJ were generated on the surface of aluminum plates. The annular shapes have been used to focus acoustic waves toward the center. In this work, a photorefractive adaptive interferometer set up based on Two-Wave Mixing in a fast BSO crystal was used to probe and detect the converging acoustic pulses at the center of the laser generated rings. By moving the detection point about 1 mm out of the ring epicenter, the amplitude of bulk and surface waves drop quickly which shows the converging evidence of the acoustic waves in the ring center. For a 3 mm thick aluminum plate, the ring size from 1 mm to 10 mm was scanned. The optimum ring diameter and the focal length of the acoustic waves along the central axis were found. Applications of this technique in subsurface defects detection as well as sample thickness measurement are investigated.

  14. GENERATING FRACTAL PATTERNS BY USING p-CIRCLE INVERSION

    NASA Astrophysics Data System (ADS)

    Ramírez, José L.; Rubiano, Gustavo N.; Zlobec, Borut Jurčič

    2015-10-01

    In this paper, we introduce the p-circle inversion which generalizes the classical inversion with respect to a circle (p = 2) and the taxicab inversion (p = 1). We study some basic properties and we also show the inversive images of some basic curves. We apply this new transformation to well-known fractals such as Sierpinski triangle, Koch curve, dragon curve, Fibonacci fractal, among others. Then we obtain new fractal patterns. Moreover, we generalize the method called circle inversion fractal be means of the p-circle inversion.

  15. Testing polycyclicity of finitely generated rational matrix groups

    NASA Astrophysics Data System (ADS)

    Assmann, Bjoern; Eick, Bettina

    2007-09-01

    We describe algorithms for testing polycyclicity and nilpotency for finitely generated subgroups of mathrm{GL}(d,mathbb{Q}) and thus we show that these properties are decidable. Variations of our algorithm can be used for testing virtual polycyclicity and virtual nilpotency for finitely generated subgroups of mathrm{GL}(d,mathbb{Q}) .

  16. Model Based Analysis and Test Generation for Flight Software

    NASA Technical Reports Server (NTRS)

    Pasareanu, Corina S.; Schumann, Johann M.; Mehlitz, Peter C.; Lowry, Mike R.; Karsai, Gabor; Nine, Harmon; Neema, Sandeep

    2009-01-01

    We describe a framework for model-based analysis and test case generation in the context of a heterogeneous model-based development paradigm that uses and combines Math- Works and UML 2.0 models and the associated code generation tools. This paradigm poses novel challenges to analysis and test case generation that, to the best of our knowledge, have not been addressed before. The framework is based on a common intermediate representation for different modeling formalisms and leverages and extends model checking and symbolic execution tools for model analysis and test case generation, respectively. We discuss the application of our framework to software models for a NASA flight mission.

  17. Testing to Characterize the Advanced Stirling Radioisotope Generator Engineering Unit

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward; Schreiber, Jeffrey

    2010-01-01

    The Advanced Stirling Radioisotope Generator (ASRG), a high efficiency generator, is being considered for space missions. Lockheed Martin designed and fabricated an engineering unit (EU), the ASRG EU, under contract to the Department of Energy. This unit is currently undergoing extended operation testing at the NASA Glenn Research Center to generate performance data and validate life and reliability predictions for the generator and the Stirling convertors. It has also undergone performance tests to characterize generator operation while varying control parameters and system inputs. This paper summarizes and explains test results in the context of designing operating strategies for the generator during a space mission and notes expected differences between the EU performance and future generators.

  18. A method for generating precise temporal patterns of retinal spiking using prosthetic stimulation.

    PubMed

    Fried, S I; Hsueh, H A; Werblin, F S

    2006-02-01

    The goal of retinal prosthetic devices is to generate meaningful visual information in patients that have lost outer retinal function. To accomplish this, these devices should generate patterns of ganglion cell activity that closely resemble the spatial and temporal components of those patterns that are normally elicited by light. Here, we developed a stimulus paradigm that generates precise temporal patterns of activity in retinal ganglion cells, including those patterns normally generated by light. Electrical stimulus pulses (> or =1-ms duration) elicited activity in neurons distal to the ganglion cells; this resulted in ganglion cell spiking that could last as long as 100 ms. However, short pulses, <0.15 ms, elicited only a single spike within 0.7 ms of the leading edge of the pulse. Trains of these short pulses elicited one spike per pulse at frequencies < or =250 Hz. Patterns of short electrical pulses (derived from normal light elicited spike patterns) were delivered to ganglion cells and generated spike patterns that replicated the normal light patterns. Finally, we found that one spike per pulse was elicited over almost a 2.5:1 range of stimulus amplitudes. Thus a common stimulus amplitude could accommodate a 2.5:1 range of activation thresholds, e.g., caused by differences arising from cell biophysical properties or from variations in electrode-to-cell distance arising when a multielectrode array is placed on the retina. This stimulus paradigm can generate the temporal resolution required for a prosthetic device. PMID:16236780

  19. Morphodynamics and anabranching patterns generated in the Madeira River, Brazil

    NASA Astrophysics Data System (ADS)

    Latrubesse, E. M.; Bonthius, C.; Abad, J. D.; Stevaux, J.; Filizola, N.; Frias, C. E.

    2013-12-01

    The Madeira River is the largest tributary in water discharge and sediment transport of the Amazon River. At present, this river is at the center of a controversial political discussion because the Brazilian government is building two hydroelectric plants on the Bolivia-Brazil border, flooding a long reach from near Cachuela Esperanza in the tributary Beni River, close to the Brazil-Bolivia border, up to Porto Velho. We present results from three field expeditions carried out in July-August 2011, December 2012 and March 2013. The main scope of this article is to disseminate the environmental threat suffered by the Madeira from regulation/disruption, and to present preliminary results on the geomorphologic characteristics of the Madeira channel and floodplain. Using historical radar and satellite imagery, the floodplain morpho-sedimentary units and morphology of the channel were assessed and quantified. Sediment bed and bank sampling, bathymetric surveys and velocity measurements were recorded using a single beam echo sounder and an acoustic Doppler current profiler (ADCP), respectively. Velocity data were analyzed using TRDI's WinRiverII and a MATLAB-based software package Velocity Mapping Tool. We consider that the Madeira River offers some ideal conditions to provide information on critical conditions and geomorphologic thresholds in mega-rivers. The Madeira River has been classified as a simple to moderate anabranching low-sinuosity river. The Madeira flows through a relatively simple pattern, alternating straight reaches with others that exhibit an incipient tendency to anabranch. Single beam and ADCP data yields insight into the bathymetry and flow characteristics in the channel through straight, pseudo-meandering, and anabranching stretches. We studied in detail three selected three reaches zones where three primary mechanisms for anabranching were identified: a) branches upstream and downstream in box shape pseudo-meanders; b) simple branch patterns developing downstream a straight single channel reach; and c) branches in sinuous-second order lateral channels. Velocity maps and an analysis of secondary currents provide information on the three-dimensional flows of water within the channel indicating that bed and channel morphology affect hydraulic characteristics. Several cross sections present unusually deep pools up to ~80m depth in the outer bank and significant increases in the local water slope. These are related to geological constraints, which manifest in the over deepening from the preferentially downwards secondary flow, exacerbating erosion. The anabranching patterns in large rivers such as the Madeira are not just controlled by intrinsic morphodynamics and hydraulic geometry variables but though a variety of interactions with the architecture of the floodplain and the control exerted by older fluvial geomorphological units.

  20. Topology-generating interfacial pattern formation during liquid metal dealloying

    SciTech Connect

    Geslin, Pierre -Antoine; McCue, Ian; Gaskey, Bernard; Erlebacher, Jonah; Karma, Alain

    2015-11-19

    Liquid metal dealloying has emerged as a novel technique to produce topologically complex nanoporous and nanocomposite structures with ultra-high interfacial area and other unique properties relevant for diverse material applications. This process is empirically known to require the selective dissolution of one element of a multicomponent solid alloy into a liquid metal to obtain desirable structures. However, how structures form is not known. Here we demonstrate, using mesoscale phase-field modelling and experiments, that nano/microstructural pattern formation during dealloying results from the interplay of (i) interfacial spinodal decomposition, forming compositional domain structures enriched in the immiscible element, and (ii) diffusion-coupled growth of the enriched solid phase and the liquid phase into the alloy. We highlight how those two basic mechanisms interact to yield a rich variety of topologically disconnected and connected structures. Furthermore, we deduce scaling laws governing microstructural length scales and dealloying kinetics.

  1. Topology-generating interfacial pattern formation during liquid metal dealloying

    PubMed Central

    Geslin, Pierre-Antoine; McCue, Ian; Gaskey, Bernard; Erlebacher, Jonah; Karma, Alain

    2015-01-01

    Liquid metal dealloying has emerged as a novel technique to produce topologically complex nanoporous and nanocomposite structures with ultra-high interfacial area and other unique properties relevant for diverse material applications. This process is empirically known to require the selective dissolution of one element of a multicomponent solid alloy into a liquid metal to obtain desirable structures. However, how structures form is not known. Here we demonstrate, using mesoscale phase-field modelling and experiments, that nano/microstructural pattern formation during dealloying results from the interplay of (i) interfacial spinodal decomposition, forming compositional domain structures enriched in the immiscible element, and (ii) diffusion-coupled growth of the enriched solid phase and the liquid phase into the alloy. We highlight how those two basic mechanisms interact to yield a rich variety of topologically disconnected and connected structures. Moreover, we deduce scaling laws governing microstructural length scales and dealloying kinetics. PMID:26582248

  2. Topology-generating interfacial pattern formation during liquid metal dealloying

    NASA Astrophysics Data System (ADS)

    Geslin, Pierre-Antoine; McCue, Ian; Gaskey, Bernard; Erlebacher, Jonah; Karma, Alain

    2015-11-01

    Liquid metal dealloying has emerged as a novel technique to produce topologically complex nanoporous and nanocomposite structures with ultra-high interfacial area and other unique properties relevant for diverse material applications. This process is empirically known to require the selective dissolution of one element of a multicomponent solid alloy into a liquid metal to obtain desirable structures. However, how structures form is not known. Here we demonstrate, using mesoscale phase-field modelling and experiments, that nano/microstructural pattern formation during dealloying results from the interplay of (i) interfacial spinodal decomposition, forming compositional domain structures enriched in the immiscible element, and (ii) diffusion-coupled growth of the enriched solid phase and the liquid phase into the alloy. We highlight how those two basic mechanisms interact to yield a rich variety of topologically disconnected and connected structures. Moreover, we deduce scaling laws governing microstructural length scales and dealloying kinetics.

  3. Topology-generating interfacial pattern formation during liquid metal dealloying.

    PubMed

    Geslin, Pierre-Antoine; McCue, Ian; Gaskey, Bernard; Erlebacher, Jonah; Karma, Alain

    2015-01-01

    Liquid metal dealloying has emerged as a novel technique to produce topologically complex nanoporous and nanocomposite structures with ultra-high interfacial area and other unique properties relevant for diverse material applications. This process is empirically known to require the selective dissolution of one element of a multicomponent solid alloy into a liquid metal to obtain desirable structures. However, how structures form is not known. Here we demonstrate, using mesoscale phase-field modelling and experiments, that nano/microstructural pattern formation during dealloying results from the interplay of (i) interfacial spinodal decomposition, forming compositional domain structures enriched in the immiscible element, and (ii) diffusion-coupled growth of the enriched solid phase and the liquid phase into the alloy. We highlight how those two basic mechanisms interact to yield a rich variety of topologically disconnected and connected structures. Moreover, we deduce scaling laws governing microstructural length scales and dealloying kinetics. PMID:26582248

  4. Topology-generating interfacial pattern formation during liquid metal dealloying

    DOE PAGESBeta

    Geslin, Pierre -Antoine; McCue, Ian; Gaskey, Bernard; Erlebacher, Jonah; Karma, Alain

    2015-11-19

    Liquid metal dealloying has emerged as a novel technique to produce topologically complex nanoporous and nanocomposite structures with ultra-high interfacial area and other unique properties relevant for diverse material applications. This process is empirically known to require the selective dissolution of one element of a multicomponent solid alloy into a liquid metal to obtain desirable structures. However, how structures form is not known. Here we demonstrate, using mesoscale phase-field modelling and experiments, that nano/microstructural pattern formation during dealloying results from the interplay of (i) interfacial spinodal decomposition, forming compositional domain structures enriched in the immiscible element, and (ii) diffusion-coupled growthmore » of the enriched solid phase and the liquid phase into the alloy. We highlight how those two basic mechanisms interact to yield a rich variety of topologically disconnected and connected structures. Furthermore, we deduce scaling laws governing microstructural length scales and dealloying kinetics.« less

  5. Model-Driven Test Generation of Distributed Systems

    NASA Technical Reports Server (NTRS)

    Easwaran, Arvind; Hall, Brendan; Schweiker, Kevin

    2012-01-01

    This report describes a novel test generation technique for distributed systems. Utilizing formal models and formal verification tools, spe cifically the Symbolic Analysis Laboratory (SAL) tool-suite from SRI, we present techniques to generate concurrent test vectors for distrib uted systems. These are initially explored within an informal test validation context and later extended to achieve full MC/DC coverage of the TTEthernet protocol operating within a system-centric context.

  6. Tests and evaluation of multihundred watt thermoelectric generators at JPL

    NASA Technical Reports Server (NTRS)

    Rouklove, P.

    1977-01-01

    The multihundred watt (MHW) thermoelectric generator, based on silicon-germanium thermoelectric technology, delivers a nominal power output of 150 watts with an efficiency of about 6%. The two Voyager space probes each use three such generators assembled in tandem on a boom. A total of seven MHW type thermoelectric generators were tested at JPL in support of the Voyager project. The tests consisted of: (1) parametric evaluation of the electrical characteristics of the devices over a wide range of output voltage for different values of input power, different operating ambients (air, vacuum), and different internal environments (argon, helium, xenon, mixture of these gases, and vacuum) at different pressures to allow evaluation of the influences of both gas and pressure on the performance of the generator; (2) tests to determine the transient behavior of the generators; and (3) operation of the generator in conjunction with the Voyager spacecraft.

  7. Testing of a direct drive generator for wind turbines

    SciTech Connect

    Sondergaard, L.M.

    1996-12-31

    The normal drive train of a wind turbine consists a gearbox and a 4 to 8 poles asynchronous generator. The gearbox is an expensive and unreliable components and this paper deals with testing of a direct drive synchronous generator for a gearless wind turbine. The Danish company Belt Electric has constructed and manufactured a 27 kW prototype radial flux PM-generator (DD600). They have used cheap hard ferrite magnets in the rotor of this PM-generator. This generator has been tested at Riso and the test results are investigated and analyzed in this paper. The tests have been done with three different load types (1: resistance; 2: diode rectifier, DC-capacitor, resistance; 3: AC-capacitor, diode rectifier, DC-capacitor, resistance). 1 ref., 9 figs., 5 tabs.

  8. Gas Generation Testing of Neptunium Oxide at Elevated Temperature

    SciTech Connect

    Duffey, JM

    2004-01-30

    Elevated temperature gas generation tests have been conducted using neptunium dioxide produced on a laboratory scale using the HB-Line Phase II flowsheet. These tests were performed to determine what effect elevated temperatures would have on the neptunium dioxide in comparison to neptunium dioxide tested at ambient temperature. The headspace gas compositions following storage at elevated temperatures associated with normal conditions of transport (NCT) have been measured. These test results show an increase in hydrogen generation rate at elevated temperature and significant removal of oxygen from the headspace gas. The elevated temperature gas generation tests described in this report involved heating small test vessels containing neptunium dioxide and measuring the headspace gas pressure and composition at the end of the test period. Four samples were used in these tests to evaluate the impact of process variables on the gas generation rate. Two samples were calcined to 600 degrees Celsius and two were calcined to 650 degrees Celsius. Each test vessel contained approximately 9.5 g of neptunium dioxide. Following exposure to 75 per cent relative humidity (RH) for five days, these samples were loaded in air and then heated to between 105 and 115 degrees Celsius for about one month. At the conclusion of the test period, the headspace gas of each container was analyzed using a micro-gas chromatograph installed in the glovebox where the experiments were conducted. The pressure, volume, and composition data for the headspace gas samples were used to calculate average H2 generation rates.

  9. Patterns of cancer in first generation immigrants from the Arab League and other countries.

    PubMed

    Kato, Ikuko; Yee, Cecilia L; Ruterbusch, Julie; Schwartz, Kendra

    2009-01-01

    Arabic immigrants are a relatively new group of immigrants and one of the fastest growing populations in the United States. Yet, information about their disease patterns is limited because Arabic is not a recognized minority group in population statistics. We tested whether population-based cancer registry data were useful to describe cancer patterns of the first generation of Arabic immigrants, compared with non-immigrants as well as the first generation of other immigrants. Information on invasive cancer cases with only one primary and known age was extracted from Surveillance, Epidemiology, and End Results (SEER) public use data (1973-2004) and software. Immigrants were divided by place of birth; Arabic: born in the Arab League countries, and other immigrants: born in countries other than the United States or Arab League, whereas US-born were used as a reference population. Information on place of birth was frequently absent for non-deceased cases, therefore data were limited to deceased cases. Age- and gender-standardized proportional ratios (SPR) were calculated for 24 aggregated cancer sites. Significantly high or low SPRs were observed for Arabic immigrants for the following cancer sites: liver (3.15), gallbladder & other biliary (1.87), thyroid (1.74), stomach (1.54), leukemia (1.41), lymphoma (1.36), pancreas (1.36), ovary (1.29), brain and other nervous system (1.23), lung (0.80), prostate (0.72), oral cavity and pharynx (0.64), esophagus (0.39), and skin melanoma (0.33). These patterns were similar for the other immigrants; however, ovary and brain were Arabic-specific, and thus may deserve further investigation for specific environmental or genetic exposures among Arabic immigrants. PMID:19999650

  10. Statistical Tests of the Apple IIe Random Number Generator Yield Suggestions from Generator Seeding.

    ERIC Educational Resources Information Center

    Gleason, John M.

    1988-01-01

    Discusses flaws in the Apple IIe Applesoft random number generator, RND, and reports results of frequency and serial correlation tests of the generator. Suggestions of seeds that yield sequences of numbers which pass fundamental screening tests for randomness are presented. (Author/LRW)

  11. Quantitative Analysis of the Drosophila Segmentation Regulatory Network Using Pattern Generating Potentials

    PubMed Central

    Richards, Adam; McCutchan, Michael; Wakabayashi-Ito, Noriko; Hammonds, Ann S.; Celniker, Susan E.; Kumar, Sudhir; Wolfe, Scot A.; Brodsky, Michael H.; Sinha, Saurabh

    2010-01-01

    Cis-regulatory modules that drive precise spatial-temporal patterns of gene expression are central to the process of metazoan development. We describe a new computational strategy to annotate genomic sequences based on their “pattern generating potential” and to produce quantitative descriptions of transcriptional regulatory networks at the level of individual protein-module interactions. We use this approach to convert the qualitative understanding of interactions that regulate Drosophila segmentation into a network model in which a confidence value is associated with each transcription factor-module interaction. Sequence information from multiple Drosophila species is integrated with transcription factor binding specificities to determine conserved binding site frequencies across the genome. These binding site profiles are combined with transcription factor expression information to create a model to predict module activity patterns. This model is used to scan genomic sequences for the potential to generate all or part of the expression pattern of a nearby gene, obtained from available gene expression databases. Interactions between individual transcription factors and modules are inferred by a statistical method to quantify a factor's contribution to the module's pattern generating potential. We use these pattern generating potentials to systematically describe the location and function of known and novel cis-regulatory modules in the segmentation network, identifying many examples of modules predicted to have overlapping expression activities. Surprisingly, conserved transcription factor binding site frequencies were as effective as experimental measurements of occupancy in predicting module expression patterns or factor-module interactions. Thus, unlike previous module prediction methods, this method predicts not only the location of modules but also their spatial activity pattern and the factors that directly determine this pattern. As databases of transcription factor specificities and in vivo gene expression patterns grow, analysis of pattern generating potentials provides a general method to decode transcriptional regulatory sequences and networks. PMID:20808951

  12. Mechanisms of Left-Right Coordination in Mammalian Locomotor Pattern Generation Circuits: A Mathematical Modeling View

    PubMed Central

    Talpalar, Adolfo E.; Rybak, Ilya A.

    2015-01-01

    The locomotor gait in limbed animals is defined by the left-right leg coordination and locomotor speed. Coordination between left and right neural activities in the spinal cord controlling left and right legs is provided by commissural interneurons (CINs). Several CIN types have been genetically identified, including the excitatory V3 and excitatory and inhibitory V0 types. Recent studies demonstrated that genetic elimination of all V0 CINs caused switching from a normal left-right alternating activity to a left-right synchronized “hopping” pattern. Furthermore, ablation of only the inhibitory V0 CINs (V0D subtype) resulted in a lack of left-right alternation at low locomotor frequencies and retaining this alternation at high frequencies, whereas selective ablation of the excitatory V0 neurons (V0V subtype) maintained the left–right alternation at low frequencies and switched to a hopping pattern at high frequencies. To analyze these findings, we developed a simplified mathematical model of neural circuits consisting of four pacemaker neurons representing left and right, flexor and extensor rhythm-generating centers interacting via commissural pathways representing V3, V0D, and V0V CINs. The locomotor frequency was controlled by a parameter defining the excitation of neurons and commissural pathways mimicking the effects of N-methyl-D-aspartate on locomotor frequency in isolated rodent spinal cord preparations. The model demonstrated a typical left-right alternating pattern under control conditions, switching to a hopping activity at any frequency after removing both V0 connections, a synchronized pattern at low frequencies with alternation at high frequencies after removing only V0D connections, and an alternating pattern at low frequencies with hopping at high frequencies after removing only V0V connections. We used bifurcation theory and fast-slow decomposition methods to analyze network behavior in the above regimes and transitions between them. The model reproduced, and suggested explanation for, a series of experimental phenomena and generated predictions available for experimental testing. PMID:25970489

  13. Test Input Generation for Red-Black Trees using Abstraction

    NASA Technical Reports Server (NTRS)

    Visser, Willem; Pasareanu, Corina S.; Pelanek, Radek

    2005-01-01

    We consider the problem of test input generation for code that manipulates complex data structures. Test inputs are sequences of method calls from the data structure interface. We describe test input generation techniques that rely on state matching to avoid generation of redundant tests. Exhaustive techniques use explicit state model checking to explore all the possible test sequences up to predefined input sizes. Lossy techniques rely on abstraction mappings to compute and store abstract versions of the concrete states; they explore under-approximations of all the possible test sequences. We have implemented the techniques on top of the Java PathFinder model checker and we evaluate them using a Java implementation of red-black trees.

  14. Generation of Customizable Micro-wavy Pattern through Grayscale Direct Image Lithography

    NASA Astrophysics Data System (ADS)

    He, Ran; Wang, Shunqiang; Andrews, Geoffrey; Shi, Wentao; Liu, Yaling

    2016-02-01

    With the increasing amount of research work in surface studies, a more effective method of producing patterned microstructures is highly desired due to the geometric limitations and complex fabricating process of current techniques. This paper presents an efficient and cost-effective method to generate customizable micro-wavy pattern using direct image lithography. This method utilizes a grayscale Gaussian distribution effect to model inaccuracies inherent in the polymerization process, which are normally regarded as trivial matters or errors. The measured surface profiles and the mathematical prediction show a good agreement, demonstrating the ability of this method to generate wavy patterns with precisely controlled features. An accurate pattern can be generated with customizable parameters (wavelength, amplitude, wave shape, pattern profile, and overall dimension). This mask-free photolithography approach provides a rapid fabrication method that is capable of generating complex and non-uniform 3D wavy patterns with the wavelength ranging from 12 μm to 2100 μm and an amplitude-to-wavelength ratio as large as 300%. Microfluidic devices with pure wavy and wavy-herringbone patterns suitable for capture of circulating tumor cells are made as a demonstrative application. A completely customized microfluidic device with wavy patterns can be created within a few hours without access to clean room or commercial photolithography equipment.

  15. Generation of Customizable Micro-wavy Pattern through Grayscale Direct Image Lithography.

    PubMed

    He, Ran; Wang, Shunqiang; Andrews, Geoffrey; Shi, Wentao; Liu, Yaling

    2016-01-01

    With the increasing amount of research work in surface studies, a more effective method of producing patterned microstructures is highly desired due to the geometric limitations and complex fabricating process of current techniques. This paper presents an efficient and cost-effective method to generate customizable micro-wavy pattern using direct image lithography. This method utilizes a grayscale Gaussian distribution effect to model inaccuracies inherent in the polymerization process, which are normally regarded as trivial matters or errors. The measured surface profiles and the mathematical prediction show a good agreement, demonstrating the ability of this method to generate wavy patterns with precisely controlled features. An accurate pattern can be generated with customizable parameters (wavelength, amplitude, wave shape, pattern profile, and overall dimension). This mask-free photolithography approach provides a rapid fabrication method that is capable of generating complex and non-uniform 3D wavy patterns with the wavelength ranging from 12 μm to 2100 μm and an amplitude-to-wavelength ratio as large as 300%. Microfluidic devices with pure wavy and wavy-herringbone patterns suitable for capture of circulating tumor cells are made as a demonstrative application. A completely customized microfluidic device with wavy patterns can be created within a few hours without access to clean room or commercial photolithography equipment. PMID:26902520

  16. From Central Pattern Generator to Sensory Template in the Evolution of Birdsong

    ERIC Educational Resources Information Center

    Konishi, Masakazu

    2010-01-01

    Central nervous networks, be they a part of the human brain or a group of neurons in a snail, may be designed to produce distinct patterns of movement. Central pattern generators can account for the development and production of normal vocal signals without auditory feedback in non-songbirds. Songbirds need auditory feedback to develop and…

  17. From Central Pattern Generator to Sensory Template in the Evolution of Birdsong

    ERIC Educational Resources Information Center

    Konishi, Masakazu

    2010-01-01

    Central nervous networks, be they a part of the human brain or a group of neurons in a snail, may be designed to produce distinct patterns of movement. Central pattern generators can account for the development and production of normal vocal signals without auditory feedback in non-songbirds. Songbirds need auditory feedback to develop and…

  18. Making a Swim Central Pattern Generator Out of Latent Parabolic Bursters

    NASA Astrophysics Data System (ADS)

    Alaçam, Deniz; Shilnikov, Andrey

    2015-06-01

    We study the rhythmogenesis of oscillatory patterns emerging in network motifs composed of inhibitory coupled tonic spiking neurons represented by the Plant model of R15 nerve cells. Such motifs are argued to be used as building blocks for a larger central pattern generator network controlling swim locomotion of sea slug Melibe leonina.

  19. Central Pattern Generation and the Motor Infrastructure for Suck, Respiration, and Speech

    ERIC Educational Resources Information Center

    Barlow, Steven M.; Estep, Meredith

    2006-01-01

    The objective of the current report is to review experimental findings on centrally patterned movements and sensory and descending modulation of central pattern generators (CPGs) in a variety of animal and human models. Special emphasis is directed toward speech production muscle systems, including the chest wall and orofacial complex during…

  20. Generation of Customizable Micro-wavy Pattern through Grayscale Direct Image Lithography

    PubMed Central

    He, Ran; Wang, Shunqiang; Andrews, Geoffrey; Shi, Wentao; Liu, Yaling

    2016-01-01

    With the increasing amount of research work in surface studies, a more effective method of producing patterned microstructures is highly desired due to the geometric limitations and complex fabricating process of current techniques. This paper presents an efficient and cost-effective method to generate customizable micro-wavy pattern using direct image lithography. This method utilizes a grayscale Gaussian distribution effect to model inaccuracies inherent in the polymerization process, which are normally regarded as trivial matters or errors. The measured surface profiles and the mathematical prediction show a good agreement, demonstrating the ability of this method to generate wavy patterns with precisely controlled features. An accurate pattern can be generated with customizable parameters (wavelength, amplitude, wave shape, pattern profile, and overall dimension). This mask-free photolithography approach provides a rapid fabrication method that is capable of generating complex and non-uniform 3D wavy patterns with the wavelength ranging from 12 μm to 2100 μm and an amplitude-to-wavelength ratio as large as 300%. Microfluidic devices with pure wavy and wavy-herringbone patterns suitable for capture of circulating tumor cells are made as a demonstrative application. A completely customized microfluidic device with wavy patterns can be created within a few hours without access to clean room or commercial photolithography equipment. PMID:26902520

  1. Performance testing of a Transit generator at JPL.

    NASA Technical Reports Server (NTRS)

    Rouklove, P.

    1973-01-01

    A Transit type thermoelectric generator, serial number QM-III, assembled with lightweight Isotec type thermoelectric panels, has been placed on test at the Jet Propulsion Laboratory. In its exterior appearance and main constructive features, generator QM-III is similar to the generator which was flown on the Transit satellite, launched into circular polar orbit on Sept. 2, 1972. The main difference between the flight generator and QM-III is that the flight hardware is heated by radioisotope decay, while QM-III is an ETG and is assembled with three different types of thermoelectric panels. The paper describes the generator and test equipment used and presents the results of the tests performed to date.

  2. Hemispatial PCA dissociates temporal from parietal ERP generator patterns

    PubMed Central

    Tenke, Craig E.; Kayser, Jürgen; Shankman, Stewart A.; Griggs, Carlye B.; Leite, Paul; Stewart, Jonathan W.; Bruder, Gerard E.

    2008-01-01

    Event-related potentials (31-channel ERPs) were recorded from 38 depressed, unmedicated outpatients and 26 healthy adults (all right-handed) in tonal and phonetic oddball tasks developed to exploit the perceptual challenge of a dichotic stimulation. Tonal nontargets were pairs of complex tones (corresponding to musical notes G and B above middle C) presented simultaneously to each ear (L/R) in an alternating series (G/B or B/G; 2-s fixed SOA). A target tone (note A) replaced one of the pair on 20% of the trials (A/B, G/A, B/A, A/G). Phonetic nontargets were L/R pairs of syllables (/ba/, /da/) with a short voice onset time (VOT), and targets contained a syllable (/ta/) with a long VOT. Subjects responded with a left or right button press to targets (counterbalanced across blocks). Target detection was poorer in patients than controls and for tones than syllables. Reference-free current source densities (CSDs; spherical spline Laplacian) derived from ERP waveforms were simplified and measured using temporal, covariance-based PCA followed by unrestricted Varimax rotation. Target-related N2 sinks and mid-parietal P3 sources were represented by CSD factors peaking at 245 and 440 ms. The P3 source topography included a secondary, left-lateralized temporal lobe maximum for both targets and nontargets. However, a subsequent hemispheric spatiotemporal PCA disentangled temporal lobe N1 and P3 sources as distinct factors. P3 sources were reduced in patients compared with controls, even after using performance as a covariate. Results are consistent with prior reports of P3 reduction in depression and implicate distinct parietal and temporal generators of P3 when using a dichotic oddball paradigm. PMID:17963912

  3. Measurement resolution of noise directivity patterns from acoustic flight tests

    NASA Technical Reports Server (NTRS)

    Conner, David A.

    1989-01-01

    The measurement resolution of noise directivity patterns from acoustic flight tests was investigated. Directivity angle resolution is affected by the data reduction parameters, the aircraft velocity and flyover altitude, and by deviations of the aircraft from the desired flight path. Equations are developed which determine bounds for the lateral and longitudinal directivity angle resolution as a function of the nominal directivity angle. The equations are applied to a flight test data base and the effects of several flight conditions and data reduction parameters on the directivity angle resolution are presented. The maximum directivity angle resolution typically occurs when the aircraft is at or near the overhead position. In general, directivity angle resolution improves with decreasing velocity, increasing altitude, increasing sampling rate, decreasing block size, and decreasing block averages. Deviations from the desired ideal flight path will increase the resolution. For the flight experiment considered in this study, an average of two flyovers were required at each test condition to obtain an acceptable flight path. The ability of the pilot to maintain the flight track improved with decreasing altitude, decreasing velocity, and practice. Due to the prevailing wind conditions, yaw angles of as much as 20 deg were required to maintain the desired flight path.

  4. Feedback-Based Coverage Directed Test Generation: An Industrial Evaluation

    NASA Astrophysics Data System (ADS)

    Ioannides, Charalambos; Barrett, Geoff; Eder, Kerstin

    Although there are quite a few approaches to Coverage Directed test Generation aided by Machine Learning which have been applied successfully to small and medium size digital designs, it is not clear how they would scale on more elaborate industrial-level designs. This paper evaluates one of these techniques, called MicroGP, on a fully fledged industrial design. The results indicate relative success evidenced by a good level of code coverage achieved with reasonably compact tests when compared to traditional test generation approaches. However, there is scope for improvement especially with respect to the diversity of the tests evolved.

  5. MINET validation study using steam generator test data

    SciTech Connect

    Van Tuyle, G.J.; Guppy, J.G.

    1984-01-01

    Three steam generator transient test cases that were simulated using the MINET computer code are described, with computed results compared against experimental data. The MINET calculations closely agreed with the experiment for both the once-through and the U-tube steam generator test cases. The effort is part of an ongoing effort to validate the MINET computer code for thermal-hydraulic plant systems transient analysis, and strongly supports the validity of the MINET models.

  6. Precision test apparatus for evaluating the heating pattern of radiofrequency ablation devices.

    PubMed

    Chang, I; Beard, B

    2002-11-01

    Radiofrequency has established itself as a useful technique for managing cardiac arrhythmias and treating soft tissue tumors. However, despite its pervasive use, many of the biophysical principals needed to fully understand and optimize the radiofrequency ablation technique have not been explored. We have designed a test rig that is useful for studying the heat transfer mechanisms that affect the outcome of radiofrequency ablation devices. Using both solid and liquid phantom materials, which simulate body tissues and blood, the test rig is designed for systematic testing of the effects of predictable flow patterns on the temperature profiles generated within the solid phantom. The test rig consists of a custom built thermistor array, a linear test chamber, and a radiofrequency generator. We calibrate the flow of a liquid phantom material to demonstrate that predictable laminar flow profiles are generated. To demonstrate the performance of the ablation system, we present preliminary data attained using a commercially available cardiac ablation catheter. The advantages of this test system are its flexibility, its reproducibility, its precision, and its low cost. Thus, it is ideally suited for studying a variety of complex ablation problems involving multiple tissues types and complex blood flow geometries. PMID:12376050

  7. Comparison between LCOS projector and DLP projector in generating digital sinusoidal fringe patterns

    NASA Astrophysics Data System (ADS)

    Li, Beiwen; Gibson, John; Middendorf, Jill; Wang, Yajun; Zhang, Song

    2013-09-01

    Digital-light-processing (DLP) and liquid-crystal-on-silicon (LCOS) are two digital projection technologies which enjoy great popularity. This paper will demonstrate the performance of the two technologies in generating digital sinusoidal fringe patterns in the two following ways: focused-sinusoidal-patterns (FSP) method and defocused-binary-patterns (DBP) method. Experiment shows that for the FSP method, LCOS projector is a better choice since nonlinear gamma effect is less significant and there is no need for precise synchronization; While for the DBP method, DLP projector has the advantage over LCOS projector since the generated images have higher contrast ratio.

  8. Alcohol Consumption Patterns in Immigrant and Later Generation Mexican American Women.

    ERIC Educational Resources Information Center

    Gilbert, M. Jean

    1987-01-01

    Immigrant Mexican women's drinking patterns were compared with those of Mexican women in Mexico, other United States Latinas, later-generation Mexican-American women, and male immigrants. Changes in the direction of greater permissiveness and rationalization of alcohol use among later-generation Mexican-American women are demonstrated. (JMM)

  9. Using triangle-based cubic interpolation in generation of object-adaptive fringe pattern

    NASA Astrophysics Data System (ADS)

    Peng, Junzheng; Yu, Yingjie; Zhou, Wenjing; Chen, Mingyi

    2014-01-01

    The object-adaptive fringe projection technique employs user-defined uneven spaced fringe patterns, instead of the evenly spaced fringe patterns, to measure the deformation of the object surface. With this technique, the quality of the object-adaptive fringe patterns is very important for guaranteeing the measurement accuracy. In this paper, a simple and effective method to generate such fringe patterns based on the cubic Beziér interpolation is presented. It can realize the cubic Beziér interpolation through three nearest points and thereby the time required for generating the adaptive fringe patterns is significantly reduced without loss of accuracy. Numerical simulations and experiments have demonstrated the accuracy and effectiveness of the proposed method.

  10. Experience with on-line generator partial discharge tests

    NASA Astrophysics Data System (ADS)

    Kurtz, M.; Stone, G. C.; Jannaway, W. F.

    1981-12-01

    Partial discharge tests found useful in assessing the condition of stator winding insulation systems in hydraulic generators and in the early detection of incipient problems are discussed. This on-line test procedure was not only found to be less costly to implement than early methods, but also was shown to be capable of yielding meaningful data under noisy conditions.

  11. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... CFR part 1065. (2) Torque is normalized to the maximum torque at the rpm listed with it. Therefore, to.... The generation of the maximum torque curve is described in 40 CFR part 1065. (b) Example of the... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065....

  12. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... CFR part 1065. (2) Torque is normalized to the maximum torque at the rpm listed with it. Therefore, to.... The generation of the maximum torque curve is described in 40 CFR part 1065. (b) Example of the... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065....

  13. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CFR part 1065. (2) Torque is normalized to the maximum torque at the rpm listed with it. Therefore, to.... The generation of the maximum torque curve is described in 40 CFR part 1065. (b) Example of the... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065....

  14. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CFR part 1065. (2) Torque is normalized to the maximum torque at the rpm listed with it. Therefore, to.... The generation of the maximum torque curve is described in 40 CFR part 1065. (b) Example of the... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065....

  15. Long term tests of a SNAP-19 thermoelectric generator.

    NASA Technical Reports Server (NTRS)

    Rouklove, P.; Truscello, V.

    1972-01-01

    Results of tests performed on a SNAP 19 thermoelectric generator, SN-20. The SN-20 generator was tested for approximately 37,000 hours using electrical heating to simulate the heat released by isotope decay. After 27,000 hours of operation the output power from the generator decreased to approximately 1/3 of the beginning of life value while the internal resistance increased by a factor of 5. Analysis of the test results, confirmed by preliminary metallographic examination, indicated that the output power degradation was the result of excessive sublimation of the thermoelectric material and loss of the hot junction bond due to the depletion of the internal cover gas. This also resulted in excessive junction temperatures. Comparison is made with the behavior observed from the two flight generators and a tentative conclusion is advanced as to the reason for their failure.

  16. Flexibility of motor pattern generation across stimulation conditions by the neonatal rat spinal cord.

    PubMed

    Klein, David A; Patino, Angelica; Tresch, Matthew C

    2010-03-01

    Previous studies have demonstrated that "locomotor-like" rhythmic patterns can be evoked in the isolated neonatal rat spinal cord by several means, including pharmacological neuromodulation and electrical stimulation of various pathways. Recent studies have used stimulation of afferent pathways to evoke rhythmic patterns, relying on synaptic activation of interneuronal systems rather than global imposition of neuromodulatory state by pharmacological agents. We use the in vitro neonatal rat spinal cord with attached hindlimb to examine the muscle activation patterns evoked by stimulation of these different pathways and evaluate whether stimulation of these pathways all evoke the same patterns. We find that the patterns evoked by bath application of serotonin (5-HT) and N-methyl-D-aspartic acid (NMDA) consisted of alternation between hip flexors and extensors and similar alternation was observed in the patterns evoked by electrical stimulation of the cauda equina (CE) or contralateral fifth lumbar (L(5)) dorsal nerve root. In contrast, the knee extensor/hip flexor rectus femoris (RF) and knee flexor/hip extensor semitendinosus (ST) were activated differentially across stimulation conditions. In 5-HT/NMDA patterns, RF was active in late flexion and ST in late extension. In CE patterns, these two muscles switched places with RF typically active in late extension and ST active in flexion. In L(5) patterns, ST was activated in extension and RF was silent or weakly active during flexion. There were also systematic differences in the consistency of rhythms evoked by each stimulation method: patterns evoked by electrical stimulation of CE or L(5) were less consistently modulated with the rhythm when compared with 5-HT/NMDA-evoked patterns. All differences were preserved following deafferentation, demonstrating that they reflect intrinsic properties of spinal systems. These results highlight the intrinsic flexibility of motor pattern generation by spinal motor circuitry which is present from birth and provides important information to many studies examining spinal pattern generating networks. PMID:20089814

  17. Development and Test of a Prototype 100MVA Superconducting Generator

    SciTech Connect

    Fogarty, James M.; Bray, James W.

    2007-05-25

    In 2002, General Electric and the US Department of Energy (DOE) entered into a cooperative agreement for the development of a commercialized 100 MVA generator using high temperature superconductors (HTS) in the field winding. The intent of the program was to: • Identify and develop technologies that would be needed for such a generator. • Develop conceptual designs for generators with ratings of 100 MVA and higher using HTS technology. • Perform proof of concept tests at the 1.5 MW level for GE’s proprietary warm iron rotor HTS generator concept. • Design, build, and test a prototype of a commercially viable 100 MVA generator that could be placed on the power grid. This report summarizes work performed during the program and is provided as one of the final program deliverables.

  18. High-quality generation of a multispot pattern using a spatial light modulator with adaptive feedback.

    PubMed

    Matsumoto, Naoya; Inoue, Takashi; Ando, Taro; Takiguchi, Yu; Ohtake, Yoshiyuki; Toyoda, Haruyoshi

    2012-08-01

    We propose and demonstrate high-quality generation of a uniform multispot pattern (MSP) by using a spatial light modulator with adaptive feedback. The method iteratively updates a computer generated hologram (CGH) using correction coefficients to improve the intensity distribution of the generated MSP in the optical system. Thanks to a simple method of determining the correction coefficients, the computational cost for optimizing the CGH is low, while maintaining high uniformity of the generated MSP. We demonstrate the generation of a 28×28 square-aligned MSP with high uniformity. Additionally, the proposed method could generate an MSP with a gradually varying intensity profile, as well as a uniform MSP consisting of more than 1000 spots arranged in an arbitrary pattern. PMID:22859110

  19. A Test Generation Framework for Distributed Fault-Tolerant Algorithms

    NASA Technical Reports Server (NTRS)

    Goodloe, Alwyn; Bushnell, David; Miner, Paul; Pasareanu, Corina S.

    2009-01-01

    Heavyweight formal methods such as theorem proving have been successfully applied to the analysis of safety critical fault-tolerant systems. Typically, the models and proofs performed during such analysis do not inform the testing process of actual implementations. We propose a framework for generating test vectors from specifications written in the Prototype Verification System (PVS). The methodology uses a translator to produce a Java prototype from a PVS specification. Symbolic (Java) PathFinder is then employed to generate a collection of test cases. A small example is employed to illustrate how the framework can be used in practice.

  20. Dynamic test input generation for multiple-fault isolation

    NASA Technical Reports Server (NTRS)

    Schaefer, Phil

    1990-01-01

    Recent work is Causal Reasoning has provided practical techniques for multiple fault diagnosis. These techniques provide a hypothesis/measurement diagnosis cycle. Using probabilistic methods, they choose the best measurements to make, then update fault hypotheses in response. For many applications such as computers and spacecraft, few measurement points may be accessible, or values may change quickly as the system under diagnosis operates. In these cases, a hypothesis/measurement cycle is insufficient. A technique is presented for a hypothesis/test-input/measurement diagnosis cycle. In contrast to generating tests a priori for determining device functionality, it dynamically generates tests in response to current knowledge about fault probabilities. It is shown how the mathematics previously used for measurement specification can be applied to the test input generation process. An example from an efficient implementation called Multi-Purpose Causal (MPC) is presented.

  1. Constancy and variability in the output of a central pattern generator.

    PubMed

    Norris, Brian J; Wenning, Angela; Wright, Terrence Michael; Calabrese, Ronald L

    2011-03-23

    Experimental and corresponding modeling studies have demonstrated a twofold to fivefold variation of intrinsic and synaptic parameters across animals, whereas functional output is maintained. These studies have led to the hypothesis that correlated, compensatory changes in particular parameters can at least partially explain the biological variability in parameters. Using the leech heartbeat central pattern generator (CPG), we selected three different segmental motor neurons that fire in a functional phase progression but receive input from the same four premotor interneurons. Previous work suggested that the phase progression arises because the pattern of relative strength of the four inputs varies systematically across the segmental motor neurons. Nevertheless, there was considerable animal-to-animal variation in the absolute strengths of these connections. We tested the hypothesis that functional output is maintained in the face of variation in the absolute strength of connections because relative strengths onto particular motor neurons are maintained. We found that relative strength is not strictly maintained across animals even as functional output is maintained, and animal-to-animal variations in relative strength of particular inputs do not correlate strongly with output phase. In parallel with this variation in synaptic strength, the firing phase of the premotor inputs to these motor neurons varies considerably across individuals. We conclude that the number (four) of inputs to each motor neuron, which each vary in strength, and the phase diversity of the temporal pattern of input from the CPG diminish the influence of individual inputs. We hypothesize that each animal arrives at a unique solution for how the network produces functional output. PMID:21430165

  2. Pigment cell movement is not required for generation of Turing patterns in zebrafish skin

    NASA Astrophysics Data System (ADS)

    Bullara, D.; de Decker, Y.

    2015-05-01

    The zebrafish is a model organism for pattern formation in vertebrates. Understanding what drives the formation of its coloured skin motifs could reveal pivotal to comprehend the mechanisms behind morphogenesis. The motifs look and behave like reaction-diffusion Turing patterns, but the nature of the underlying physico-chemical processes is very different, and the origin of the patterns is still unclear. Here we propose a minimal model for such pattern formation based on a regulatory mechanism deduced from experimental observations. This model is able to produce patterns with intrinsic wavelength, closely resembling the experimental ones. We mathematically prove that their origin is a Turing bifurcation occurring despite the absence of cell motion, through an effect that we call differential growth. This mechanism is qualitatively different from the reaction-diffusion originally proposed by Turing, although they both generate the short-range activation and the long-range inhibition required to form Turing patterns.

  3. Pigment cell movement is not required for generation of Turing patterns in zebrafish skin

    PubMed Central

    Bullara, D.; De Decker, Y.

    2015-01-01

    The zebrafish is a model organism for pattern formation in vertebrates. Understanding what drives the formation of its coloured skin motifs could reveal pivotal to comprehend the mechanisms behind morphogenesis. The motifs look and behave like reaction–diffusion Turing patterns, but the nature of the underlying physico-chemical processes is very different, and the origin of the patterns is still unclear. Here we propose a minimal model for such pattern formation based on a regulatory mechanism deduced from experimental observations. This model is able to produce patterns with intrinsic wavelength, closely resembling the experimental ones. We mathematically prove that their origin is a Turing bifurcation occurring despite the absence of cell motion, through an effect that we call differential growth. This mechanism is qualitatively different from the reaction–diffusion originally proposed by Turing, although they both generate the short-range activation and the long-range inhibition required to form Turing patterns. PMID:25959141

  4. Collapsed haplotype pattern method for linkage analysis of next-generation sequence data.

    PubMed

    Wang, Gao T; Zhang, Di; Li, Biao; Dai, Hang; Leal, Suzanne M

    2015-12-01

    Recent advances in next-generation sequencing (NGS) make it possible to directly sequence genomes and exomes of individuals with Mendelian diseases and screen sequence data for causal variants. With the reduction in cost of NGS, DNA samples from entire families can be sequenced and linkage analysis can be performed directly using NGS data. Inspired by 'burden' tests, which are used for complex trait rare variant association studies, we developed the collapsed haplotype pattern (CHP) method for linkage analysis. Using data from several deafness genes we demonstrate that the CHP method is substantially more powerful than analyzing individual variants. Unlike applying NGS data filtering approaches, the CHP method provides statistical evidence of a gene's involvement in disease etiology and is also less likely to exclude causal variants in the presence of phenocopies and/or reduced penetrance. The CHP method was implemented in the SEQLinkage software package, which can perform linkage analysis on NGS data or can generate data compatible with many linkage analysis programs, reviving them for use in NGS era. PMID:25873013

  5. Exploring a type of central pattern generator based on Hindmarsh-Rose model: from theory to application.

    PubMed

    Zhang, Dingguo; Zhang, Qing; Zhu, Xiangyang

    2015-02-01

    This paper proposes the idea that Hindmarsh-Rose (HR) neuronal model can be used to develop a new type of central pattern generator (CPG). Some key properties of HR model are studied and proved to meet the requirements of CPG. Pros and cons of HR model are provided. A CPG network based on HR model is developed and the related properties are investigated. We explore the bipedal primary gaits generated by the CPG network. The preliminary applications of HR model are tested on humanoid locomotion model and functional electrical stimulation (FES) walking system. The positive results of stimulation and experiment show the feasibility of HR model as a valid CPG. PMID:25146328

  6. Automated Generation and Assessment of Autonomous Systems Test Cases

    NASA Technical Reports Server (NTRS)

    Barltrop, Kevin J.; Friberg, Kenneth H.; Horvath, Gregory A.

    2008-01-01

    This slide presentation reviews some of the issues concerning verification and validation testing of autonomous spacecraft routinely culminates in the exploration of anomalous or faulted mission-like scenarios using the work involved during the Dawn mission's tests as examples. Prioritizing which scenarios to develop usually comes down to focusing on the most vulnerable areas and ensuring the best return on investment of test time. Rules-of-thumb strategies often come into play, such as injecting applicable anomalies prior to, during, and after system state changes; or, creating cases that ensure good safety-net algorithm coverage. Although experience and judgment in test selection can lead to high levels of confidence about the majority of a system's autonomy, it's likely that important test cases are overlooked. One method to fill in potential test coverage gaps is to automatically generate and execute test cases using algorithms that ensure desirable properties about the coverage. For example, generate cases for all possible fault monitors, and across all state change boundaries. Of course, the scope of coverage is determined by the test environment capabilities, where a faster-than-real-time, high-fidelity, software-only simulation would allow the broadest coverage. Even real-time systems that can be replicated and run in parallel, and that have reliable set-up and operations features provide an excellent resource for automated testing. Making detailed predictions for the outcome of such tests can be difficult, and when algorithmic means are employed to produce hundreds or even thousands of cases, generating predicts individually is impractical, and generating predicts with tools requires executable models of the design and environment that themselves require a complete test program. Therefore, evaluating the results of large number of mission scenario tests poses special challenges. A good approach to address this problem is to automatically score the results based on a range of metrics. Although the specific means of scoring depends highly on the application, the use of formal scoring - metrics has high value in identifying and prioritizing anomalies, and in presenting an overall picture of the state of the test program. In this paper we present a case study based on automatic generation and assessment of faulted test runs for the Dawn mission, and discuss its role in optimizing the allocation of resources for completing the test program.

  7. Localization of Motor Neurons and Central Pattern Generators for Motor Patterns Underlying Feeding Behavior in Drosophila Larvae

    PubMed Central

    Hückesfeld, Sebastian; Schoofs, Andreas; Schlegel, Philipp; Miroschnikow, Anton; Pankratz, Michael J.

    2015-01-01

    Motor systems can be functionally organized into effector organs (muscles and glands), the motor neurons, central pattern generators (CPG) and higher control centers of the brain. Using genetic and electrophysiological methods, we have begun to deconstruct the motor system driving Drosophila larval feeding behavior into its component parts. In this paper, we identify distinct clusters of motor neurons that execute head tilting, mouth hook movements, and pharyngeal pumping during larval feeding. This basic anatomical scaffold enabled the use of calcium-imaging to monitor the neural activity of motor neurons within the central nervous system (CNS) that drive food intake. Simultaneous nerve- and muscle-recordings demonstrate that the motor neurons innervate the cibarial dilator musculature (CDM) ipsi- and contra-laterally. By classical lesion experiments we localize a set of CPGs generating the neuronal pattern underlying feeding movements to the subesophageal zone (SEZ). Lesioning of higher brain centers decelerated all feeding-related motor patterns, whereas lesioning of ventral nerve cord (VNC) only affected the motor rhythm underlying pharyngeal pumping. These findings provide a basis for progressing upstream of the motor neurons to identify higher regulatory components of the feeding motor system. PMID:26252658

  8. Gas Generation from K East Basin Sludges - Series II Testing

    SciTech Connect

    Bryan, Samuel A.; Delegard, Calvin H.; Schmidt, Andrew J.; Sell, Rachel L.; Silvers, Kurt L.; Gano, Susan R.; Thornton, Brenda M.

    2001-03-14

    This report describes work to examine the gas generation behavior of actual K East (KE) Basin floor, pit and canister sludge. Mixed and unmixed and fractionated KE canister sludge were tested, along with floor and pit sludges from areas in the KE Basin not previously sampled. The first report in this series focused on gas generation from KE floor and canister sludge collected using a consolidated sampling technique. The third report will present results of gas generation testing of irradiated uranium fuel fragments with and without sludge addition. The path forward for management of the K Basin Sludge is to retrieve, ship, and store the sludge at T Plant until final processing at some future date. Gas generation will impact the designs and costs of systems associated with retrieval, transportation and storage of sludge.

  9. NASA Fastrac Engine Gas Generator Component Test Program and Results

    NASA Technical Reports Server (NTRS)

    Dennis, Henry J., Jr.; Sanders, Tim; Turner, James E. (Technical Monitor)

    2000-01-01

    This presentation consists of viewgraph which review the test program and the results of the tests for the Gas Generator (GG) component for the Fastrac Engine. Included are pictures of the Fastrac (MC-1) Engine and the GG, diagrams of the flight configuration, and schematics of the LOX, and the RP-1 systems and the injector assembly. The normal operating parameters are reviewed, as are the test instrumentation. Also shown are graphs of the hot gas temperature, and the test temperature profiles. The results are summarized.

  10. Generative Models of Segregation: Investigating Model-Generated Patterns of Residential Segregation by Ethnicity and Socioeconomic Status

    PubMed Central

    Fossett, Mark

    2011-01-01

    This paper considers the potential for using agent models to explore theories of residential segregation in urban areas. Results of generative experiments conducted using an agent-based simulation of segregation dynamics document that varying a small number of model parameters representing constructs from urban-ecological theories of segregation can generate a wide range of qualitatively distinct and substantively interesting segregation patterns. The results suggest how complex, macro-level patterns of residential segregation can arise from a small set of simple micro-level social dynamics operating within particular urban-demographic contexts. The promise and current limitations of agent simulation studies are noted and optimism is expressed regarding the potential for such studies to engage and contribute to the broader research literature on residential segregation. PMID:21379372

  11. Generation of patterned neuronal networks on cell-repellant poly(oligo(ethylene glycol) methacrylate) films.

    PubMed

    Kang, Kyungtae; Kang, Gyumin; Lee, Bong Soo; Choi, Insung S; Nam, Yoonkey

    2010-08-01

    The utilization of non-biofouling poly(oligo(ethylene glycol) methacrylate) (pOEGMA) films as a background material for the generation of neuronal patterns is reported here. Our previously reported method, which was surface-initiated, atom transfer radical polymerization of OEGMA, and subsequent activation of terminal hydroxyl groups of pOEGMA with disuccinimidyl carbonate, was employed for the generation of activated pOEGMA films on glass. Poly-L-lysine was then microcontact-printed onto the activated polymer films, followed by backfilling with poly(ethylene glycol) moieties. E18 hippocampal neurons were cultured on the chemically patterned substrate, and the resulting neuronal networks were analyzed by phase-contrast microscopy and whole-cell patch clamp method. The results indicated that the pOEGMA films played an important role in the generation of good-quality neuronal patterns for up to two weeks without any negative effects to neurons. PMID:20391470

  12. Generating Reduced Tests for FSMs with Extra States

    NASA Astrophysics Data System (ADS)

    Simão, Adenilso; Petrenko, Alexandre; Yevtushenko, Nina

    We address the problem of generating tests from a deterministic Finite State Machine to provide full fault coverage even if the faults may introduce extra states in the implementations. It is well-known that such tests should include the sequences in the so-called traversal set, which contains all sequences of length defined by the number of extra states. Therefore, the only apparent opportunity to produce shorter tests is to find within a test suite a suitable arrangement of the sequences in the inescapable traversal set. We observe that the direct concatenation of the traversal set to a given state cover, suggested by all existing generation methods with full fault coverage, results in extensive test branching, when a test has to be repeatedly executed to apply all the sequences of the traversal set. In this paper, we state conditions which allow distributing these sequences over several tests. We then utilize these conditions to elaborate a method, called SPY-method, which shortens tests by avoiding test branching as much as possible. We present the results of the experimental comparison of the proposed method with an existing method which indicate that the resulting save can be up to 40%.

  13. Design, fabrication, and evaluation of diffractive optical elements for generation of focused ring patterns

    NASA Astrophysics Data System (ADS)

    Vijayakumar, A.; Bhattacharya, Shanti

    2015-02-01

    Focused ring patterns are used for many applications like corneal surgery, micro drilling, optical trapping, etc. The generation of focused ring patterns in the earlier reported cases employed many refractive optical components with different functions. As a result the optics configurations of the ring pattern generation systems are bulkier. In diffractive optics, it is possible to alter a function of an element and also integrate multiple functions in a single element. In this paper, we present the design, fabrication and evaluation of single and composite diffractive optical elements for the generation of focused ring patterns. A diffractive toric Fresnel zone lens was designed for parallel beam illumination. This element is compared with other composite diffractive elements capable of generating focused ring patterns. The toric Fresnel zone lens and composite elements were fabricated using electron beam direct writing. The fabricated elements were found to exhibit interesting properties, with the toric lens out-performing the other elements in several areas such as efficiency, focal depth, and ring thickness.

  14. Prototype steam generator test at SCTI/ETEC. Acoustic program test plan. [LMFBR

    SciTech Connect

    Greene, D.A.; Thiele, A.; Claytor, T.N.

    1981-10-01

    This document is an integrated test plan covering programs at General Electric (ARSD), Rockwell International (RI) and Argonne National Laboratory (CT). It provides an overview of the acoustic leak detection test program which will be completed in conjunction with the prototype LMFBR steam generator at the Energy Technology Engineering Laboratory. The steam generator is installed in the Sodium Components Test Installation (SCTI). Two acoustic detection systems will be used during the test program, a low frequency system developed by GE-ARSD (GAAD system) and a high frequency system developed by RI-AI (HALD system). These systems will be used to acquire data on background noise during the thermal-hydraulic test program. Injection devices were installed during fabrication of the prototype steam generator to provide localized noise sources in the active region of the tube bundle. These injectors will be operated during the steam generator test program, and it will be shown that they are detected by the acoustic systems.

  15. Focal high cell density generates a gradient of patterns in self-organizing vascular mesenchymal cells.

    PubMed

    Cheng, Henry; Reddy, Aneela; Sage, Andrew; Lu, Jinxiu; Garfinkel, Alan; Tintut, Yin; Demer, Linda L

    2012-01-01

    In embryogenesis, structural patterns, such as vascular branching, may form via a reaction-diffusion mechanism in which activator and inhibitor morphogens guide cells into periodic aggregates. We previously found that vascular mesenchymal cells (VMCs) spontaneously aggregate into nodular structures and that morphogen pairs regulate the aggregation into patterns of spots and stripes. To test the effect of a focal change in activator morphogen on VMC pattern formation, we created a focal zone of high cell density by plating a second VMC layer within a cloning ring over a confluent monolayer. After 24 h, the ring was removed and pattern formation monitored by phase-contrast microscopy. At days 2-8, the patterns progressed from uniform distributions to swirl, labyrinthine and spot patterns. Within the focal high-density zone (HDZ) and a narrow halo zone, cells aggregated into spot patterns, whilst in the outermost zone of the plate, cells formed a labyrinthine pattern. The area occupied by aggregates was significantly greater in the outermost zone than in the HDZ or halo. The rate of pattern progression within the HDZ increased as a function of its plating density. Thus, focal differences in cell density may drive pattern formation gradients in tissue architecture, such as vascular branching. PMID:22797747

  16. Experiments with Test Case Generation and Runtime Analysis

    NASA Technical Reports Server (NTRS)

    Artho, Cyrille; Drusinsky, Doron; Goldberg, Allen; Havelund, Klaus; Lowry, Mike; Pasareanu, Corina; Rosu, Grigore; Visser, Willem; Koga, Dennis (Technical Monitor)

    2003-01-01

    Software testing is typically an ad hoc process where human testers manually write many test inputs and expected test results, perhaps automating their execution in a regression suite. This process is cumbersome and costly. This paper reports preliminary results on an approach to further automate this process. The approach consists of combining automated test case generation based on systematically exploring the program's input domain, with runtime analysis, where execution traces are monitored and verified against temporal logic specifications, or analyzed using advanced algorithms for detecting concurrency errors such as data races and deadlocks. The approach suggests to generate specifications dynamically per input instance rather than statically once-and-for-all. The paper describes experiments with variants of this approach in the context of two examples, a planetary rover controller and a space craft fault protection system.

  17. Next Generation Advanced Video Guidance Sensor Development and Test

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.; Bryan, Thomas C.; Lee, Jimmy; Robertson, Bryan

    2009-01-01

    The Advanced Video Guidance Sensor (AVGS) was the primary docking sensor for the Orbital Express mission. The sensor performed extremely well during the mission, and the technology has been proven on orbit in other flights too. Parts obsolescence issues prevented the construction of more AVGS units, so the next generation of sensor was designed with current parts and updated to support future programs. The Next Generation Advanced Video Guidance Sensor (NGAVGS) has been tested as a breadboard, two different brassboard units, and a prototype. The testing revealed further improvements that could be made and demonstrated capability beyond that ever demonstrated by the sensor on orbit. This paper presents some of the sensor history, parts obsolescence issues, radiation concerns, and software improvements to the NGAVGS. In addition, some of the testing and test results are presented. The NGAVGS has shown that it will meet the general requirements for any space proximity operations or docking need.

  18. Structural vibration control by tuned mass damper using central pattern generator

    NASA Astrophysics Data System (ADS)

    Iba, Daisuke; Hongu, Junichi

    2011-04-01

    This paper proposes a new control method for active mass dampers using a Central Pattern Generator in vibration mitigation. The active mass dampers (or active dynamic absorbers) have been applied to structural vibration control of high-rise buildings, bridges and so on. In this case, the mass of the active mass damper must oscillate in an appropriate phase in relation to the control object, and generally, the damper has been designed by linear control theory as pole placement method, optimal control method or H infinity control method, and all the rest. On the other hand, on walking of animate beings like mammals or insects, both side feet have appropriate phase relations; moreover, it is possible to keep moving on irregular ground. That is, algorithms for the walking would be embedded into the animate beings to control the complicated and redundant bodies with ease and robustness. In biological study, the Central Pattern Generators in bodies playing a significant role in the walking have been learned over the last few decades, and some studies said that some animate beings are able to control their feet by using the generators without their brains in the walking. Moreover, mathematical models of the pattern generators have been proposed, and some researchers have been studying to realize walking of biped-robots using the pattern generators embedded in a computer. In this study, the algorithm is installed into a controller for the active mass damper; furthermore, validation of the controller is performed by numerical simulation.

  19. Testing and Functions of the J2X Gas Generator

    NASA Technical Reports Server (NTRS)

    Miller, Nicholas

    2009-01-01

    The Ares I, NASA s new solid rocket based crew launch vehicle, is a two stage in line rocket that has made its waytothe forefront of NASA s endeavors. The Ares I s Upper Stage (US) will be propelled by a J-2X engine which is fueled by liquid hydrogen and liquid oxygen. The J-2X is a variation based on two of its predecessor s, the J-2 and J-2S engines. ET50 is providing the design support for hardware required to run tests on the J-2X Gas Generator (GG) that increases the delivery pressure of the supplied combustion fuels that the engine burns. The test area will be running a series of tests using different lengths and curved segments of pipe and different sized nozzles to determine the configuration that best satisfies the thrust, heat, and stability requirements for the engine. I have had to research the configurations that are being tested and gain an understanding of the purpose of the tests. I then had to research the parts that would be used in the test configurations. I was taken to see parts similar to the ones used in the test configurations and was allowed to review drawings and dimensions used for those parts. My job over this summer has been to use the knowledge I have gained to design, model, and create drawings for the un-fabricated parts that are necessary for the J-2X Workhorse Gas Generator Phase IIcTest.

  20. Generation of optical crystals and quasicrystal beams: Kaleidoscopic patterns and phase singularity

    SciTech Connect

    Chen, Y. F.; Liang, H. C.; Lin, Y. C.; Tzeng, Y. S.; Su, K. W.; Huang, K. F.

    2011-05-15

    We explore the feasibility of the generation of pseudonondiffracting optical beams related to crystal and quasicrystal structures. It is experimentally confirmed that optical crystal and quasicrystal beams can be remarkably generated with a collimated light to illuminate a high-precision mask with multiple apertures regularly distributed on a ring. We also found that exotic kaleidoscopic patterns can be exhibited with the high-order quasicrystal beams. More importantly, the structures of phase singularities in optical quasicrystal beams are manifested.

  1. 21 CFR 864.7900 - Thromboplastin generation test.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Thromboplastin generation test. 864.7900 Section 864.7900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages §...

  2. 21 CFR 864.7900 - Thromboplastin generation test.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Thromboplastin generation test. 864.7900 Section 864.7900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages §...

  3. Automatic Generation of Tests from Domain and Multimedia Ontologies

    ERIC Educational Resources Information Center

    Papasalouros, Andreas; Kotis, Konstantinos; Kanaris, Konstantinos

    2011-01-01

    The aim of this article is to present an approach for generating tests in an automatic way. Although other methods have been already reported in the literature, the proposed approach is based on ontologies, representing both domain and multimedia knowledge. The article also reports on a prototype implementation of this approach, which…

  4. 21 CFR 864.7900 - Thromboplastin generation test.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Thromboplastin generation test. 864.7900 Section 864.7900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages §...

  5. Electronic test instrument generates extremely small current signals

    NASA Technical Reports Server (NTRS)

    Brookshier, W. K.

    1967-01-01

    Generator produces dynamic test signals in the range from 0.0001 and 10 to the minus 12th power amperes. It involves an extension of the technique of applying a triangular voltage waveform to a small capacitor to obtain a square-wave output current. The effects of stray capacitance are minimized by appropriate shielding.

  6. 49 CFR 229.114 - Steam generator inspections and tests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... train line shut-off-valve is wired closed or a blind gasket is applied. Before an isolated steam... 49 Transportation 4 2013-10-01 2013-10-01 false Steam generator inspections and tests. 229.114... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements...

  7. 49 CFR 229.114 - Steam generator inspections and tests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... train line shut-off-valve is wired closed or a blind gasket is applied. Before an isolated steam... 49 Transportation 4 2014-10-01 2014-10-01 false Steam generator inspections and tests. 229.114... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements...

  8. 49 CFR 229.114 - Steam generator inspections and tests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... train line shut-off-valve is wired closed or a blind gasket is applied. Before an isolated steam... 49 Transportation 4 2012-10-01 2012-10-01 false Steam generator inspections and tests. 229.114... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements...

  9. Testing a Student Generated Hypothesis Using Student Data

    ERIC Educational Resources Information Center

    McGowan, Herle M.; Vaughan, Joel

    2012-01-01

    We describe an activity that allows students to experience the full process of a statistical investigation, from generating the research question, to collecting data and testing a hypothesis. Implementation of the activity is described both with and without use of clickers, handheld remotes that allow instant data collection.

  10. 21 CFR 864.7900 - Thromboplastin generation test.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Thromboplastin generation test. 864.7900 Section 864.7900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages §...

  11. Automatic Generation of Tests from Domain and Multimedia Ontologies

    ERIC Educational Resources Information Center

    Papasalouros, Andreas; Kotis, Konstantinos; Kanaris, Konstantinos

    2011-01-01

    The aim of this article is to present an approach for generating tests in an automatic way. Although other methods have been already reported in the literature, the proposed approach is based on ontologies, representing both domain and multimedia knowledge. The article also reports on a prototype implementation of this approach, which…

  12. 21 CFR 864.7900 - Thromboplastin generation test.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Thromboplastin generation test. 864.7900 Section 864.7900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages §...

  13. Radioisotope thermoelectric generator licensed hardware package and certification tests

    NASA Astrophysics Data System (ADS)

    Goldmann, L. H.; Averette, H. S.

    1994-09-01

    This paper presents the Licensed Hardware package and the Certification Test portions of the Radioisotope Thermoelectric Generator Transportation System. This package has been designed to meet those portions of the Code of Federal Regulations (10 CFR 71) relating to 'Type B' shipments of radioactive materials. The detailed information for the anticipated license is presented in the safety analysis report for packaging, which is now in process and undergoing necessary reviews. As part of the licensing process, a full-size Certification Test Article unit, which has modifications slightly different than the Licensed Hardware or production shipping units, is used for testing. Dimensional checks of the Certification Test Article were made at the manufacturing facility. Leak testing and drop testing were done at the 300 Area of the US Department of Energy's Hanford Site near Richland, Washington. The hardware includes independent double containments to prevent the environmental spread of Pu-238, impact limiting devices to protect portions of the package from impacts, and thermal insulation to protect the seal areas from excess heat during accident conditions. The package also features electronic feed-throughs to monitor the Radioisotope Thermoelectric Generator's temperature inside the containment during the shipment cycle. This package is designed to safely dissipate the typical 4500 thermal watts produced in the largest Radioisotope Thermoelectric Generators. The package also contains provisions to ensure leak tightness when radioactive materials, such as a Radioisotope Thermoelectric Generator for the Cassini Mission, planned for 1997 by the National Aeronautics and Space Administration, are being prepared for shipment. These provisions include test ports used in conjunction with helium mass spectrometers to determine seal leakage rates of each containment during the assembly process.

  14. Radioisotope thermoelectric generator licensed hardware package and certification tests

    NASA Astrophysics Data System (ADS)

    Goldmann, Louis H.; Averette, Henry S.

    1995-01-01

    This paper presents the Licensed Hardware package and the Certification Test portions of the Radioisitope Themoelectric Generator Transportation System. This package has been designed to meet those portions of the Code of Federal Regulations (10 CFR 71) relating to ``Type B'' shipments of radioactive materials. The licensed hardware is now in the U. S. Department of Energy licensing process that certifies the packaging's integrity under accident conditions. The detailed information for the anticipated license is presented in the safety analysis report for packaging, which is now in process and undergoing necessary reviews. As part of the licensing process, a full-size Certification Test Article unit, which has modifications slightly different than the Licensed Hardware or production shipping units, is used for testing. Dimensional checks of the Certification Test Article were made at the manufacturing facility. Leak testing and drop testing were done at the 300 Area of the U.S. Department of Energy's Hanford Site near Richland, Washington. The hardware includes independent double containments to prevent the environmental spread of 238Pu, impact limiting devices to protect portions of the package from impacts, and thermal insulation to protect the seal areas from excess heat during accident conditions. The package also features electronic feed-throughs to monitor the Radioisotope Thermoelectric Generator's temperature inside the containment during the shipment cycle. This package is designed to safely dissipate the typical 4,500 thermal watts produced in the largest Radioisotope Thermoelectric Generators. The package also contains provisions to ensure leak tightness when radioactive materials, such as a Radioisotope Thermoelectric Generator for the Cassini Mission, planned for 1997 by the National Aeronautics and Space Administration, are being prepared for shipment. These provisions include test ports used in conjunction with helium mass spectrometers to determine seal leakage rates of each containment during the assembly process.

  15. Quantum random number generation for loophole-free Bell tests

    NASA Astrophysics Data System (ADS)

    Mitchell, Morgan; Abellan, Carlos; Amaya, Waldimar

    2015-05-01

    We describe the generation of quantum random numbers at multi-Gbps rates, combined with real-time randomness extraction, to give very high purity random numbers based on quantum events at most tens of ns in the past. The system satisfies the stringent requirements of quantum non-locality tests that aim to close the timing loophole. We describe the generation mechanism using spontaneous-emission-driven phase diffusion in a semiconductor laser, digitization, and extraction by parity calculation using multi-GHz logic chips. We pay special attention to experimental proof of the quality of the random numbers and analysis of the randomness extraction. In contrast to widely-used models of randomness generators in the computer science literature, we argue that randomness generation by spontaneous emission can be extracted from a single source.

  16. Automated Test Case Generation for an Autopilot Requirement Prototype

    NASA Technical Reports Server (NTRS)

    Giannakopoulou, Dimitra; Rungta, Neha; Feary, Michael

    2011-01-01

    Designing safety-critical automation with robust human interaction is a difficult task that is susceptible to a number of known Human-Automation Interaction (HAI) vulnerabilities. It is therefore essential to develop automated tools that provide support both in the design and rapid evaluation of such automation. The Automation Design and Evaluation Prototyping Toolset (ADEPT) enables the rapid development of an executable specification for automation behavior and user interaction. ADEPT supports a number of analysis capabilities, thus enabling the detection of HAI vulnerabilities early in the design process, when modifications are less costly. In this paper, we advocate the introduction of a new capability to model-based prototyping tools such as ADEPT. The new capability is based on symbolic execution that allows us to automatically generate quality test suites based on the system design. Symbolic execution is used to generate both user input and test oracles user input drives the testing of the system implementation, and test oracles ensure that the system behaves as designed. We present early results in the context of a component in the Autopilot system modeled in ADEPT, and discuss the challenges of test case generation in the HAI domain.

  17. Experimental laboratory system to generate high frequency test environments

    SciTech Connect

    Gregory, D.L.; Paez, T.L.

    1991-01-01

    This is an extension of two previous analytical studies to investigate a technique for generating high frequency, high amplitude vibration environments. These environments are created using a device attached to a common vibration exciter that permits multiple metal on metal impacts driving a test surface. These analytical studies predicted that test environments with an energy content exceeding 10 kHz could be achieved using sinusoidal and random shaker excitations. The analysis predicted that chaotic vibrations yielding random like test environments could be generated from sinusoidal inputs. In this study, a much simplified version of the proposed system was fabricated and tested in the laboratory. Experimental measurements demonstrate that even this simplified system, utilizing a single impacting object, can generate environments on the test surface with significant frequency content in excess of 40 kHz. Results for sinusoidal shaker inputs tuned to create chaotic impact response are shown along with the responses due to random vibration shaker inputs. The experiments and results are discussed. 4 refs., 5 figs.

  18. Improved ant algorithms for software testing cases generation.

    PubMed

    Yang, Shunkun; Man, Tianlong; Xu, Jiaqi

    2014-01-01

    Existing ant colony optimization (ACO) for software testing cases generation is a very popular domain in software testing engineering. However, the traditional ACO has flaws, as early search pheromone is relatively scarce, search efficiency is low, search model is too simple, positive feedback mechanism is easy to produce the phenomenon of stagnation and precocity. This paper introduces improved ACO for software testing cases generation: improved local pheromone update strategy for ant colony optimization, improved pheromone volatilization coefficient for ant colony optimization (IPVACO), and improved the global path pheromone update strategy for ant colony optimization (IGPACO). At last, we put forward a comprehensive improved ant colony optimization (ACIACO), which is based on all the above three methods. The proposed technique will be compared with random algorithm (RND) and genetic algorithm (GA) in terms of both efficiency and coverage. The results indicate that the improved method can effectively improve the search efficiency, restrain precocity, promote case coverage, and reduce the number of iterations. PMID:24883391

  19. Solar Stirling power generation - Systems analysis and preliminary tests

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K.; Wu, Y.-C.; Moynihan, P. I.; Day, F. D., III

    1977-01-01

    The feasibility of an electric power generation system utilizing a sun-tracking parabolic concentrator and a Stirling engine/linear alternator is being evaluated. Performance predictions and cost analysis of a proposed large distributed system are discussed. Design details and preliminary test results are presented for a 9.5 ft diameter parabolic dish at the Jet Propulsion Laboratory (Caltech) Table Mountain Test Facility. Low temperature calorimetric measurements were conducted to evaluate the concentrator performance, and a helium flow system is being used to test the solar receiver at anticipated working fluid temperatures (up to 650 or 1200 C) to evaluate the receiver thermal performance. The receiver body is designed to adapt to a free-piston Stirling engine which powers a linear alternator assembly for direct electric power generation. During the next phase of the program, experiments with an engine and receiver integrated into the concentrator assembly are planned.

  20. Improved Ant Algorithms for Software Testing Cases Generation

    PubMed Central

    Yang, Shunkun; Xu, Jiaqi

    2014-01-01

    Existing ant colony optimization (ACO) for software testing cases generation is a very popular domain in software testing engineering. However, the traditional ACO has flaws, as early search pheromone is relatively scarce, search efficiency is low, search model is too simple, positive feedback mechanism is easy to porduce the phenomenon of stagnation and precocity. This paper introduces improved ACO for software testing cases generation: improved local pheromone update strategy for ant colony optimization, improved pheromone volatilization coefficient for ant colony optimization (IPVACO), and improved the global path pheromone update strategy for ant colony optimization (IGPACO). At last, we put forward a comprehensive improved ant colony optimization (ACIACO), which is based on all the above three methods. The proposed technique will be compared with random algorithm (RND) and genetic algorithm (GA) in terms of both efficiency and coverage. The results indicate that the improved method can effectively improve the search efficiency, restrain precocity, promote case coverage, and reduce the number of iterations. PMID:24883391

  1. Thermal Analysis and Testing of Fastrac Gas Generator Design

    NASA Technical Reports Server (NTRS)

    Nguyen, H.

    1998-01-01

    The Fastrac Engine is being developed by the Marshall Space Flight Center (MSFC) to help meet the goal of substantially reducing the cost of access to space. This engine relies on a simple gas-generator cycle, which burns a small amount of RP-1 and oxygen to provide gas to drive the turbine and then exhausts the spent fuel. The Fastrac program envisions a combination of analysis, design and hot-fire evaluation testing. This paper provides the supporting thermal analysis of the gas generator design. In order to ensure that the design objectives were met, the evaluation tests have started on a component level and a total of 15 tests of different durations were completed to date at MSFC. The correlated thermal model results will also be compared against hot-fire thermocouple data gathered.

  2. Synergistic action of nectins and cadherins generates the mosaic cellular pattern of the olfactory epithelium.

    PubMed

    Katsunuma, Sayaka; Honda, Hisao; Shinoda, Tomoyasu; Ishimoto, Yukitaka; Miyata, Takaki; Kiyonari, Hiroshi; Abe, Takaya; Nibu, Ken-Ichi; Takai, Yoshimi; Togashi, Hideru

    2016-02-29

    In the olfactory epithelium (OE), olfactory cells (OCs) and supporting cells (SCs), which express different cadherins, are arranged in a characteristic mosaic pattern in which OCs are enclosed by SCs. However, the mechanism underlying this cellular patterning is unclear. Here, we show that the cellular pattern of the OE is established by cellular rearrangements during development. In the OE, OCs express nectin-2 and N-cadherin, and SCs express nectin-2, nectin-3, E-cadherin, and N-cadherin. Heterophilic trans-interaction between nectin-2 on OCs and nectin-3 on SCs preferentially recruits cadherin via α-catenin to heterotypic junctions, and the differential distributions of cadherins between junctions promote cellular intercalations, resulting in the formation of the mosaic pattern. These observations are confirmed by model cell systems, and various cellular patterns are generated by the combinatorial expression of nectins and cadherins. Collectively, the synergistic action of nectins and cadherins generates mosaic pattern, which cannot be achieved by a single mechanism. PMID:26929452

  3. Wide-field depth-sectioning fluorescence microscopy using projector-generated patterned illumination

    NASA Astrophysics Data System (ADS)

    Delica, Serafin; Mar Blanca, Carlo

    2007-10-01

    We present a simple and cost-effective wide-field, depth-sectioning, fluorescence microscope utilizing a commercial multimedia projector to generate excitation patterns on the sample. Highly resolved optical sections of fluorescent pollen grains at 1.9 ?m axial resolution are constructed using the structured illumination technique. This requires grid excitation patterns to be scanned across the sample, which is straightforwardly implemented by creating slideshows of gratings at different phases, projecting them onto the sample, and synchronizing camera acquisition with slide transition. In addition to rapid dynamic pattern generation, the projector provides high illumination power and spectral excitation selectivity. We exploit these properties by imaging mouse neural cells in cultures multistained with Alexa 488 and Cy3. The spectral and structural neural information is effectively resolved in three dimensions. The flexibility and commercial availability of this light source is envisioned to open multidimensional imaging to a broader user base.

  4. Generation of Oriented Buckling Patterns by Modulation of Local Elastic Moduli

    NASA Astrophysics Data System (ADS)

    Chan, Edwin; Crosby, Alfred

    2006-03-01

    Wrinkling patterns based on elastic instabilities are interesting due to the spontaneous formation of relief structures that consists of a dominant periodicity. While a wide variety of soft materials has been utilized to generate surface buckling patterns, alignment of these structures has only been demonstrated previously through pre-defined topographic patterns. In this contribution, we introduce a new methodology to producing aligned, or patterned, surface wrinkles through the manipulation of the local stress distributions. We define the specific regions of local differences in the elastic moduli of a poly(dimethyl siloxane) (PDMS) elastomer by selective oxidation of the PDMS surface into a silicate thin film. Subsequent swelling with a photopolymerizable monomer provides the buckling stress necessary for the formation of aligned surface wrinkles. We show that geometric confinement of the oxidized regions coupled with an osmotic stress controls the formation and orientation of the wrinkling structures.

  5. NASA Fastrac Engine Gas Generator Component Test Program and Results

    NASA Technical Reports Server (NTRS)

    Dennis, Henry J., Jr.; Sanders, T.

    2000-01-01

    Low cost access to space has been a long-time goal of the National Aeronautics and Space Administration (NASA). The Fastrac engine program was begun at NASA's Marshall Space Flight Center to develop a 60,000-pound (60K) thrust, liquid oxygen/hydrocarbon (LOX/RP), gas generator-cycle booster engine for a fraction of the cost of similar engines in existence. To achieve this goal, off-the-shelf components and readily available materials and processes would have to be used. This paper will present the Fastrac gas generator (GG) design and the component level hot-fire test program and results. The Fastrac GG is a simple, 4-piece design that uses well-defined materials and processes for fabrication. Thirty-seven component level hot-fire tests were conducted at MSFC's component test stand #116 (TS116) during 1997 and 1998. The GG was operated at all expected operating ranges of the Fastrac engine. Some minor design changes were required to successfully complete the test program as development issues arose during the testing. The test program data results and conclusions determined that the Fastrac GG design was well on the way to meeting the requirements of NASA's X-34 Pathfinder Program that chose the Fastrac engine as its main propulsion system.

  6. Production patterns of packaging waste categories generated at typical Mediterranean residential building worksites.

    PubMed

    González Pericot, N; Villoria Sáez, P; Del Río Merino, M; Liébana Carrasco, O

    2014-11-01

    The construction sector is responsible for around 28% of the total waste volume generated in Europe, which exceeds the amount of household waste. This has led to an increase of different research studies focusing on construction waste quantification. However, within the research studies made, packaging waste has been analyzed to a limited extent. This article focuses on the packaging waste stream generated in the construction sector. To this purpose current on-site waste packaging management has been assessed by monitoring ten Mediterranean residential building works. The findings of the experimental data collection revealed that the incentive measures implemented by the construction company to improve on-site waste sorting failed to achieve the intended purpose, showing low segregation ratios. Subsequently, through an analytical study the generation patterns for packaging waste are established, leading to the identification of the prevailing kinds of packaging and the products responsible for their generation. Results indicate that plastic waste generation maintains a constant trend throughout the whole construction process, while cardboard becomes predominant towards the end of the construction works with switches and sockets from the electricity stage. Understanding the production patterns of packaging waste will be beneficial for adapting waste management strategies to the identified patterns for the specific nature of packaging waste within the context of construction worksites. PMID:25081852

  7. Motor unit firing rate patterns during voluntary muscle force generation: a simulation study

    NASA Astrophysics Data System (ADS)

    Hu, Xiaogang; Rymer, William Z.; Suresh, Nina L.

    2014-04-01

    Objective. Muscle force is generated by a combination of motor unit (MU) recruitment and changes in the discharge rate of active MUs. There have been two basic MU recruitment and firing rate paradigms reported in the literature, which describe the control of the MUs during force generation. The first (termed the reverse ‘onion skin’ profile), exhibits lower firing rates for lower threshold units, with higher firing rates occurring in higher threshold units. The second (termed the ‘onion skin’ profile), exhibits an inverse arrangement, with lower threshold units reaching higher firing rates. Approach. Using a simulation of the MU activity in a hand muscle, this study examined the force generation capacity and the variability of the muscle force magnitude at different excitation levels of the MU pool under these two different MU control paradigms. We sought to determine which rate/recruitment scheme was more efficient for force generation, and which scheme gave rise to the lowest force variability. Main results. We found that the force output of both firing patterns leads to graded force output at low excitation levels, and that the force generation capacity of the two different paradigms diverged around 50% excitation. In the reverse ‘onion skin’ pattern, at 100% excitation, the force output reached up to 88% of maximum force, whereas for the ‘onion skin’ pattern, the force output only reached up to 54% of maximum force at 100% excitation. The force variability was lower at the low to moderate force levels under the ‘onion skin’ paradigm than with the reverse ‘onion skin’ firing patterns, but this effect was reversed at high force levels. Significance. This study captures the influence of MU recruitment and firing rate organization on muscle force properties, and our results suggest that the different firing organizations can be beneficial at different levels of voluntary muscle force generation and perhaps for different tasks.

  8. Facility for generating crew waste water product for ECLSS testing

    NASA Technical Reports Server (NTRS)

    Buitekant, Alan; Roberts, Barry C.

    1990-01-01

    An End-use Equipment Facility (EEF) has been constructed which is used to simulate water interfaces between the Space Station Freedom Environmental Control and Life Support Systems (ECLSS) and man systems. The EEF is used to generate waste water to be treated by ECLSS water recovery systems. The EEF will also be used to close the water recovery loop by allowing test subjects to use recovered hygiene and potable water during several phases of testing. This paper describes the design and basic operation of the EEF.

  9. Automatic Generation of Test Oracles - From Pilot Studies to Application

    NASA Technical Reports Server (NTRS)

    Feather, Martin S.; Smith, Ben

    1998-01-01

    There is a trend towards the increased use of automation in V&V. Automation can yield savings in time and effort. For critical systems, where thorough V&V is required, these savings can be substantial. We describe a progression from pilot studies to development and use of V&V automation. We used pilot studies to ascertain opportunities for, and suitability of, automating various analyses whose results would contribute to V&V. These studies culminated in the development of an automatic generator of automated test oracles. This was then applied and extended in the course of testing an Al planning system that is a key component of an autonomous spacecraft.

  10. Generation of Simulated Tracking Data for LADEE Operational Readiness Testing

    NASA Technical Reports Server (NTRS)

    Woodburn, James; Policastri, Lisa; Owens, Brandon

    2015-01-01

    Operational Readiness Tests were an important part of the pre-launch preparation for the LADEE mission. The generation of simulated tracking data to stress the Flight Dynamics System and the Flight Dynamics Team was important for satisfying the testing goal of demonstrating that the software and the team were ready to fly the operational mission. The simulated tracking was generated in a manner to incorporate the effects of errors in the baseline dynamical model, errors in maneuver execution and phenomenology associated with various tracking system based components. The ability of the mission team to overcome these challenges in a realistic flight dynamics scenario indicated that the team and flight dynamics system were ready to fly the LADEE mission. Lunar Atmosphere and Dust Environment.

  11. Testing and evaluation of Second-Generation Heliostat mirror modules

    SciTech Connect

    Burolla, V.P.; Delameter, W.R.

    1982-01-01

    The testing and evaluation of the Second Generation Heliostat mirror modules are reported here. It was found that all of the previous design problems of mirror modules, such as silver corrosion, thermal defocus, and high glass stress, were eliminated by one or more of these designs. The single most important conclusion to be drawn from this program is that laminated glass mirror module designs are the most technically conservative; it is Sandia's recommendation that this concept be used for near-term applications. Two other Second Generation designs were found to have potential for reduced weight and improved performance, but one design required some significant design changes, and both require further outdoor testing to better estimate their lifetime potential.

  12. Neuromorphic control of stepping pattern generation: a dynamic model with analog circuit implementation.

    PubMed

    Yang, Zhijun; Cameron, Katherine; Lewinger, William; Webb, Barbara; Murray, Alan

    2012-03-01

    Animals such as stick insects can adaptively walk on complex terrains by dynamically adjusting their stepping motion patterns. Inspired by the coupled Matsuoka and resonate-and-fire neuron models, we present a nonlinear oscillation model as the neuromorphic central pattern generator (CPG) for rhythmic stepping pattern generation. This dynamic model can also be used to actuate the motoneurons on a leg joint with adjustable driving frequencies and duty cycles by changing a few of the model parameters while operating such that different stepping patterns can be generated. A novel mixed-signal integrated circuit design of this dynamic model is subsequently implemented, which, although simplified, shares the equivalent output performance in terms of the adjustable frequency and duty cycle. Three identical CPG models being used to drive three joints can make an arthropod leg of three degrees of freedom. With appropriate initial circuit parameter settings, and thus suitable phase lags among joints, the leg is expected to walk on a complex terrain with adaptive steps. The adaptation is associated with the circuit parameters mediated both by the higher level nervous system and the lower level sensory signals. The model is realized using a 0.3- complementary metal-oxide-semiconductor process and the results are reported. PMID:24808545

  13. Chicano Drug Abuse Patterns: Using Archival Data to Test Hypotheses.

    ERIC Educational Resources Information Center

    Hunsaker, Alan C.

    1985-01-01

    The records of 274,709 clients admitted to federally funded drug treatment programs in California between 1975 and early 1981 were examined to determine Chicano drug abuse patterns. The study confirmed the disproportionate use of heroin and inhalants by Chicanos and indicated that phencyclidine was disproportionately used by Chicanos. (NQA)

  14. Shape matching utilizing indexed hypotheses generation and testing

    NASA Technical Reports Server (NTRS)

    Mehrotra, Rajiv; Grosky, William I.

    1989-01-01

    An indexing mechanism is developed as part of an overall scheme called SMITH (shape matching utilizing indexed hypothesis generation and testing) for two-dimensional model-based object recognition. The approach is based on a dynamic programming implementation of attributed string matching, is computationally efficient, and works effectively for both nonoccluded and occluded shapes. Another advantage of this technique is that models may be inserted or deleted with relatively little cost.

  15. NREL Next Generation Drivetrain: Mechanical Design and Test Plan (Poster)

    SciTech Connect

    Keller, J.; Halse, C.

    2014-05-01

    The Department of Energy and industry partners are sponsoring a $3m project for design and testing of a 'Next Generation' wind turbine drivetrain at the National Renewable Energy Laboratory (NREL). This poster focuses on innovative aspects of the gearbox design, completed as part of an end-to-end systems engineering approach incorporating innovations that increase drivetrain reliability, efficiency, torque density and minimize capital cost.

  16. Production patterns of packaging waste categories generated at typical Mediterranean residential building worksites

    SciTech Connect

    González Pericot, N.; Villoria Sáez, P.; Del Río Merino, M.; Liébana Carrasco, O.

    2014-11-15

    Highlights: • On-site segregation level: 1.80%; training and motivation strategies were not effective. • 70% Cardboard waste: from switches and sockets during the building services stage. • 40% Plastic waste: generated during structures and partition works due to palletizing. • >50% Wood packaging waste, basically pallets, generated during the envelope works. - Abstract: The construction sector is responsible for around 28% of the total waste volume generated in Europe, which exceeds the amount of household waste. This has led to an increase of different research studies focusing on construction waste quantification. However, within the research studies made, packaging waste has been analyzed to a limited extent. This article focuses on the packaging waste stream generated in the construction sector. To this purpose current on-site waste packaging management has been assessed by monitoring ten Mediterranean residential building works. The findings of the experimental data collection revealed that the incentive measures implemented by the construction company to improve on-site waste sorting failed to achieve the intended purpose, showing low segregation ratios. Subsequently, through an analytical study the generation patterns for packaging waste are established, leading to the identification of the prevailing kinds of packaging and the products responsible for their generation. Results indicate that plastic waste generation maintains a constant trend throughout the whole construction process, while cardboard becomes predominant towards the end of the construction works with switches and sockets from the electricity stage. Understanding the production patterns of packaging waste will be beneficial for adapting waste management strategies to the identified patterns for the specific nature of packaging waste within the context of construction worksites.

  17. Vesicular glutamate transporter 2 is required for central respiratory rhythm generation but not for locomotor central pattern generation.

    PubMed

    Wallén-Mackenzie, Asa; Gezelius, Henrik; Thoby-Brisson, Muriel; Nygård, Anna; Enjin, Anders; Fujiyama, Fumino; Fortin, Gilles; Kullander, Klas

    2006-11-22

    Glutamatergic excitatory neurotransmission is dependent on glutamate release from presynaptic vesicles loaded by three members of the solute carrier family, Slc17a6-8, which function as vesicular glutamate transporters (VGLUTs). Here, we show that VGLUT2 (Slc17a6) is required for life ex utero. Vglut2 null mutant mice die immediately after birth because of the absence of respiratory behavior. Investigations at embryonic stages revealed that neural circuits in the location of the pre-Bötzinger (PBC) inspiratory rhythm generator failed to become active. However, neurons with bursting pacemaker properties and anatomical integrity of the PBC area were preserved. Vesicles at asymmetric synapses were fewer and malformed in the Vglut2 null mutant hindbrain, probably causing the complete disruption of AMPA/kainate receptor-mediated synaptic activity in mutant PBC cells. The functional deficit results from an inability of PBC neurons to achieve synchronous activation. In contrast to respiratory rhythm generation, the locomotor central pattern generator of Vglut2 null mutant mice displayed normal rhythmic and coordinated activity, suggesting differences in their operating principles. Hence, the present study identifies VGLUT2-mediated signaling as an obligatory component of the developing respiratory rhythm generator. PMID:17122055

  18. Test results for sawtooth-pattern damper seals - Leakage and rotordynamic coefficients

    NASA Technical Reports Server (NTRS)

    Childs, D.; Garcia, F.

    1986-01-01

    Test results consisting of direct and transverse force coefficients are presented for eleven sawtooth-pattern damper-seal configurations. The designation 'damper' seal refers to a seal which uses a deliberately roughened stator and smooth rotor to increase the net seal damping force. The designation 'sawtooth-pattern' refers to a stator-roughness pattern whose cross section normal to the axis of the seal resembles saw teeth with the teeth direction opposing fluid motion in the direction of shaft rotation. The sawtooth pattern yields axial grooves in the stator which are interrupted by spacer elements which act as flow constrictions or 'dams'. Sawtooth-pattern seals had more damping than smooth seals but less than the round-hole-pattern seals tested previously. If damping is sacrificed, sawtooth-pattern seals can be designed to leak less than round-hole-pattern seals.

  19. Stable and flexible multiple spot pattern generation using LCOS spatial light modulator.

    PubMed

    Matsumoto, Naoya; Itoh, Haruyasu; Inoue, Takashi; Otsu, Tomoko; Toyoda, Haruyoshi

    2014-10-01

    The LCOS spatial light modulator (LCOS-SLM) can generate desired multiple spot patterns (MSPs) via the application of suitable computer-generated-holograms (CGHs), but the MSP intensity distribution varies because ambient temperature affects the phase modulation characteristic and causes wavefront distortion. To generate high-optical-quality MSPs we use our hardware-compensated (with a Peltier system to even out phase modulation) and software-corrected (via multiplication of the CGH by temperature correction coefficients) LCOS-SLMs. Experimental results with a 14 × 14 MSP generation show that the hardware-compensated LCOS-SLM provides stable MSPs between 9 to 32 °C. The software-corrected LCOS-SLM provides uniform spots over twice the temperature range obtained with conventional SLM method. We confirm that our methods are highly efficient for use in two-photon excitation microscopy application such as multifocal mulitphoton microscopy. PMID:25322047

  20. SOM-based Pattern Generator: Pattern Generation Based on the Backward Projection in a Self-Organizing Map and Its Applications

    NASA Astrophysics Data System (ADS)

    Wakuya, Hiroshi; Ishiguma, Takahiro

    A major feature of the self-organizing map (SOM) is a topology-preserving projection from the input layer to the competitive layer, and it has been used mainly as an analytical tool for discovering underlying rules in the given data set. Even though recent splendid progress in this area, there are few novel ideas to break such a conventional style. On the contrary, based on its distinctive nature, a new method for generating patterns through backward projection from the competitive layer to the input layer is proposed recently. Moreover, a promising technology for producing animation as a series of backward-projected patterns along with any pathways on the competitive layer is presented. Then, in order to carry out further considerations, some computer simulations with a variety of posed stick figures are tried in this paper. After training, four kinds of pathways, which correspond to different movements such as dancing, exercising and walking, are prepared. Though some of them does not contain any training samples, all of them worked well as we have intended in advance. As a result, it is found that the proposed method shows good performance and it is also confirmed its effectiveness.

  1. Interaction between central pattern generators for breathing and swallowing in the cat.

    PubMed Central

    Dick, T E; Oku, Y; Romaniuk, J R; Cherniack, N S

    1993-01-01

    1. We examined the interaction between central pattern generators for respiration and deglutition in decerebrate, vagotomized, paralysed and ventilated cats (n = 10), by recording activity from the following nerves: hypoglossal, phrenic, thyroarytenoid and triangularis sterni. Fictive breathing was spontaneous with carbon dioxide above the apnoeic threshold (end-tidal PCO2, 32 +/- 4 mmHg) and fictive swallowing was induced by stimulating the internal branch of the left superior laryngeal nerve (SLN) continuously (0.2 ms pulse duration, 10 Hz). 2. In all ten animals, SLN stimulation evoked short bursts of thyroarytenoid and hypoglossal nerve activity indicative of fictive swallowing. In two of ten animals, respiration was inhibited completely during deglutition. In the other eight animals, fictive breathing and swallowing occurred simultaneously. 3. With SLN stimulation below threshold for eliciting swallowing, the respiratory rhythm decreased, the duration of inspiration did not change but the duration of expiration, especially stage II, increased. Integrated nerve activities indicated that the rate of rise and peak of phrenic nerve activity decreased, stage I expiratory activity of the thyroarytenoid and especially that of the hypoglossal nerve increased and stage II expiratory activity of the triangularis sterni nerve was suppressed completely. However, if inspired carbon dioxide was increased, i.e. hypercapnic ventilation, stage II expiratory activity remained partially during continuous SLN stimulation. 4. Fictive-swallowing bursts occurred only at respiratory phase transitions. At the minimal stimulus intensity that evoked repetitive swallowing bursts, the pattern of interaction between breathing and swallowing central pattern generators was consistent for each animal (n = 7) but was different across animals. In four animals, fictive swallows occurred at the phase transition between stage II expiration and inspiration, at the transition between inspiration and stage I expiration in one animal; and in two other animals, at the transition between stage I and II of expiration. 5. The response to SLN stimulation accommodated during the stimulus train. Accommodation was evident in both the interswallow interval (ISI) which lengthened, and the interaction pattern which had fewer swallows per breath as the stimulus period progressed. In contrast to the ISI, characteristics of the fictive swallow did not accommodate. For example, duration of the swallow was constant, distributed over a narrow range throughout the stimulus train. 6. We conclude that the central pattern generators for swallowing and breathing interact. The pattern of interaction supports the three-phase theory of respiratory pattern generation.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8229859

  2. Test Anxiety in UK Schoolchildren: Prevalence and Demographic Patterns

    ERIC Educational Resources Information Center

    Putwain, David W.

    2007-01-01

    Background: Despite a large body of international literature concerning the antecedents, correlates of and treatments for test anxiety, there has been little research until recently using samples of students drawn from the UK. There is a need to establish some basic normative data for test anxiety scores in this population of students, in order to…

  3. Evolving cellular automata for diversity generation and pattern recognition: deterministic versus random strategy

    NASA Astrophysics Data System (ADS)

    Argollo de Menezes, Marcio; Brigatti, Edgardo; Schwämmle, Veit

    2013-08-01

    Microbiological systems evolve to fulfil their tasks with maximal efficiency. The immune system is a remarkable example, where the distinction between self and non-self is made by means of molecular interaction between self-proteins and antigens, triggering affinity-dependent systemic actions. Specificity of this binding and the infinitude of potential antigenic patterns call for novel mechanisms to generate antibody diversity. Inspired by this problem, we develop a genetic algorithm where agents evolve their strings in the presence of random antigenic strings and reproduce with affinity-dependent rates. We ask what is the best strategy to generate diversity if agents can rearrange their strings a finite number of times. We find that endowing each agent with an inheritable cellular automaton rule for performing rearrangements makes the system more efficient in pattern-matching than if transformations are totally random. In the former implementation, the population evolves to a stationary state where agents with different automata rules coexist.

  4. A rule-based expert system for automatic control rod pattern generation for boiling water reactors

    SciTech Connect

    Lin, L.S.; Lin, C. )

    1991-07-01

    This paper reports on an expert system for generating control rod patterns that has been developed. The knowledge is transformed into IF-THEN rules. The inference engine uses the Rete pattern matching algorithm to match facts, and rule premises and conflict resolution strategies to make the system function intelligently. A forward-chaining mechanism is adopted in the inference engine. The system is implemented in the Common Lisp programming language. The three-dimensional core simulation model performs the core status and burnup calculations. The system is successfully demonstrated by generating control rod programming for the 2894-MW (thermal) Kuosheng nuclear power plant in Taiwan. The computing time is tremendously reduced compared to programs using mathematical methods.

  5. Experimental observation of multistability and dynamic attractors in silicon central pattern generators

    NASA Astrophysics Data System (ADS)

    Zhao, Le; Nogaret, Alain

    2015-11-01

    We report on the multistability of chaotic networks of silicon neurons and demonstrate how spatiotemporal sequences of voltage oscillations are selected with timed current stimuli. A three neuron central pattern generator was built by interconnecting Hodgkin-Huxley neurons with mutually inhibitory links mimicking gap junctions. By systematically varying the timing of current stimuli applied to individual neurons, we generate the phase lag maps of neuronal oscillators and study their dependence on the network connectivity. We identify up to six attractors consisting of triphasic sequences of unevenly spaced pulses propagating clockwise and anticlockwise. While confirming theoretical predictions, our experiments reveal more complex oscillatory patterns shaped by the ratio of the pulse width to the oscillation period. Our work contributes to validating the command neuron hypothesis.

  6. Effects of Scoring by Section and Independent Scorers' Patterns on Scorer Reliability in Biology Essay Tests

    ERIC Educational Resources Information Center

    Ebuoh, Casmir N.; Ezeudu, S. A.

    2015-01-01

    The study investigated the effects of scoring by section, use of independent scorers and conventional patterns on scorer reliability in Biology essay tests. It was revealed from literature review that conventional pattern of scoring all items at a time in essay tests had been criticized for not being reliable. The study was true experimental study…

  7. Five types of nonspiking interneurons in local pattern-generating circuits of the crayfish swimmeret system

    PubMed Central

    Smarandache-Wellmann, Carmen; Weller, Cynthia; Wright, Terrence M.

    2013-01-01

    We conducted a quantitative analysis of the different nonspiking interneurons in the local pattern-generating circuits of the crayfish swimmeret system. Within each local circuit, these interneurons control the firing of the power-stroke and return-stroke motor neurons that drive swimmeret movements. Fifty-four of these interneurons were identified during physiological experiments with sharp microelectrodes and filled with dextran Texas red, Neurobiotin, or both. Five types of neurons were identified on the basis of combinations of physiological and anatomical characteristics. Anatomical categories were based on 16 anatomical parameters measured from stacks of confocal images obtained from each neuron. The results support the recognition of two functional classes: inhibitors of power stroke (IPS) and inhibitors of return stroke (IRS). The IPS class of interneuron has three morphological types with similar physiological properties. The IRS class has two morphological types with physiological properties and anatomical features different from the IPS neurons but similar within the class. Three of these five types have not been previously identified. Reviewing the evidence for dye coupling within each type, we conclude that each type of IPS neuron and one type of IRS neuron occur as a single copy in each local pattern-generating circuit. The last IRS type includes neurons that might occur as a dye-coupled pair in each local circuit. Recognition of these different interneurons in the swimmeret pattern-generating circuits leads to a refined model of the local pattern-generating circuit that includes synaptic connections that encode and decode information required for intersegmental coordination of swimmeret movements. PMID:23615552

  8. A method to engineer phase-encoded photon sieve for intensity pattern generations

    NASA Astrophysics Data System (ADS)

    Li, Zhenhua; Ma, Li; Gao, Yaru; Liu, Chunxiang; Xu, Shicai; Zhang, Meina; Cheng, Chuanfu

    2015-11-01

    We propose a novel type of photon sieve where phases of its sieved waves are encoded as radial positions of the pinholes and use such phase-encoded sieves for generating designed intensity patterns in Fresnel domain. The sieve pinholes are arranged around Fresnel-rings to eliminate the quadratic Fresnel phase factor of diffraction of the sieved waves, leading the wave propagation to be equivalent to Fraunhofer diffraction. The pinholes take constant size in this paper and realize equal amplitude in the multiple sieved waves. Their positions are adjusted radially from corresponding rings to encode wave phases, taking effect by resulting in different optical paths from them to the observation plane origin. Then along with wave propagation, the encoded phases are decoded and the required phase differences are obtained in the discrete waves. We first conduct numerical simulations to show satisfactory performance of such phase-encoded photon sieves in generating arbitrarily designed intensity patterns and describe the quality of the reconstructed patterns. Then for qualitatively verifying the phase-encoding method, we experimentally fabricate three such sieves with relatively small pinhole number and obtain the designed patterns.

  9. Key Bifurcations of Bursting Polyrhythms in 3-Cell Central Pattern Generators

    PubMed Central

    Wojcik, Jeremy; Schwabedal, Justus; Clewley, Robert; Shilnikov, Andrey L.

    2014-01-01

    We identify and describe the key qualitative rhythmic states in various 3-cell network motifs of a multifunctional central pattern generator (CPG). Such CPGs are neural microcircuits of cells whose synergetic interactions produce multiple states with distinct phase-locked patterns of bursting activity. To study biologically plausible CPG models, we develop a suite of computational tools that reduce the problem of stability and existence of rhythmic patterns in networks to the bifurcation analysis of fixed points and invariant curves of a Poincaré return maps for phase lags between cells. We explore different functional possibilities for motifs involving symmetry breaking and heterogeneity. This is achieved by varying coupling properties of the synapses between the cells and studying the qualitative changes in the structure of the corresponding return maps. Our findings provide a systematic basis for understanding plausible biophysical mechanisms for the regulation of rhythmic patterns generated by various CPGs in the context of motor control such as gait-switching in locomotion. Our analysis does not require knowledge of the equations modeling the system and provides a powerful qualitative approach to studying detailed models of rhythmic behavior. Thus, our approach is applicable to a wide range of biological phenomena beyond motor control. PMID:24739943

  10. From spinal central pattern generators to cortical network: integrated BCI for walking rehabilitation.

    PubMed

    Cheron, G; Duvinage, M; De Saedeleer, C; Castermans, T; Bengoetxea, A; Petieau, M; Seetharaman, K; Hoellinger, T; Dan, B; Dutoit, T; Sylos Labini, F; Lacquaniti, F; Ivanenko, Y

    2012-01-01

    Success in locomotor rehabilitation programs can be improved with the use of brain-computer interfaces (BCIs). Although a wealth of research has demonstrated that locomotion is largely controlled by spinal mechanisms, the brain is of utmost importance in monitoring locomotor patterns and therefore contains information regarding central pattern generation functioning. In addition, there is also a tight coordination between the upper and lower limbs, which can also be useful in controlling locomotion. The current paper critically investigates different approaches that are applicable to this field: the use of electroencephalogram (EEG), upper limb electromyogram (EMG), or a hybrid of the two neurophysiological signals to control assistive exoskeletons used in locomotion based on programmable central pattern generators (PCPGs) or dynamic recurrent neural networks (DRNNs). Plantar surface tactile stimulation devices combined with virtual reality may provide the sensation of walking while in a supine position for use of training brain signals generated during locomotion. These methods may exploit mechanisms of brain plasticity and assist in the neurorehabilitation of gait in a variety of clinical conditions, including stroke, spinal trauma, multiple sclerosis, and cerebral palsy. PMID:22272380

  11. From Spinal Central Pattern Generators to Cortical Network: Integrated BCI for Walking Rehabilitation

    PubMed Central

    Cheron, G.; Duvinage, M.; De Saedeleer, C.; Castermans, T.; Bengoetxea, A.; Petieau, M.; Seetharaman, K.; Hoellinger, T.; Dan, B.; Dutoit, T.; Sylos Labini, F.; Lacquaniti, F.; Ivanenko, Y.

    2012-01-01

    Success in locomotor rehabilitation programs can be improved with the use of brain-computer interfaces (BCIs). Although a wealth of research has demonstrated that locomotion is largely controlled by spinal mechanisms, the brain is of utmost importance in monitoring locomotor patterns and therefore contains information regarding central pattern generation functioning. In addition, there is also a tight coordination between the upper and lower limbs, which can also be useful in controlling locomotion. The current paper critically investigates different approaches that are applicable to this field: the use of electroencephalogram (EEG), upper limb electromyogram (EMG), or a hybrid of the two neurophysiological signals to control assistive exoskeletons used in locomotion based on programmable central pattern generators (PCPGs) or dynamic recurrent neural networks (DRNNs). Plantar surface tactile stimulation devices combined with virtual reality may provide the sensation of walking while in a supine position for use of training brain signals generated during locomotion. These methods may exploit mechanisms of brain plasticity and assist in the neurorehabilitation of gait in a variety of clinical conditions, including stroke, spinal trauma, multiple sclerosis, and cerebral palsy. PMID:22272380

  12. Investigation, Analysis, and Testing of Self-contained Oxygen Generators

    NASA Technical Reports Server (NTRS)

    Keddy, Christopher P.; Haas, Jon P.; Starritt, Larry

    2008-01-01

    Self Contained Oxygen Generators (SCOGs) have widespread use in providing emergency breathing oxygen in a variety of environments including mines, submarines, spacecraft, and aircraft. These devices have definite advantages over storing of gaseous or liquid oxygen. The oxygen is not generated until a chemical briquette containing a chlorate or perchlorate oxidizer and a solid metallic fuel such as iron is ignited starting a thermal decomposition process allowing gaseous oxygen to be produced. These devices are typically very safe to store, easy to operate, and have primarily only a thermal hazard to the operator that can be controlled by barriers or furnaces. Tens of thousands of these devices are operated worldwide every year without major incident. This report examines the rare case of a SCOG whose behavior was both abnormal and lethal. This particular type of SCOG reviewed is nearly identical to a flight qualified version of SCOG slated for use on manned space vehicles. This Investigative Report is a compilation of a NASA effort in conjunction with other interested parties including military and aerospace to understand the causes of the particular SCOG accident and what preventative measures can be taken to ensure this incident is not repeated. This report details the incident and examines the root causes of the observed SCOG behavior from forensic evidence. A summary of chemical and numerical analysis is provided as a background to physical testing of identical SCOG devices. The results and findings of both small scale and full scale testing are documented on a test-by-test basis along with observations and summaries. Finally, conclusions are presented on the findings of this investigation, analysis, and testing along with suggestions on preventative measures for any entity interested in the safe use of these devices.

  13. Initial second-generation PFB carbonizer pilot plant test results

    SciTech Connect

    Robertson, A.; Van Hook, J.; Froehlich, R.; Bonk, D.L.

    1992-09-01

    Second-generation pressurized fluidized bed combustion (PFBC) plants promise higher efficiency with lower costs of electricity and lower stack emissions. With a l6.55 MPa/538{degree}C/538{degree}C/63.5-mm Hg(2400-psig/1000{degree} F/1000{degree}F/2.5-in.Hg) conventional steam cycle and a 3-percent sulfur Pittsburgh No. 8 coal, a 45-percent efficiency and a cost of electricity {approximately} 20 percent lower than that of a pulverized-coal-fired plant with stack gas scrubbing are being projected. Foster Wheeler Development Corporation has constructed and is operating a second-generation PFB pilot plant at the Foster Wheeler research facility (the John Blizard Research Center) in Livingston, New Jersey. Initial results of the pilot plant carbonizer test program supporting the development of this new type of plant are presented.

  14. Initial second-generation PFB carbonizer pilot plant test results

    SciTech Connect

    Robertson, A.; Van Hook, J. ); Froehlich, R. ); Bonk, D.L. )

    1992-01-01

    Second-generation pressurized fluidized bed combustion (PFBC) plants promise higher efficiency with lower costs of electricity and lower stack emissions. With a l6.55 MPa/538{degree}C/538{degree}C/63.5-mm Hg(2400-psig/1000{degree} F/1000{degree}F/2.5-in.Hg) conventional steam cycle and a 3-percent sulfur Pittsburgh No. 8 coal, a 45-percent efficiency and a cost of electricity {approximately} 20 percent lower than that of a pulverized-coal-fired plant with stack gas scrubbing are being projected. Foster Wheeler Development Corporation has constructed and is operating a second-generation PFB pilot plant at the Foster Wheeler research facility (the John Blizard Research Center) in Livingston, New Jersey. Initial results of the pilot plant carbonizer test program supporting the development of this new type of plant are presented.

  15. NeuroPG: open source software for optical pattern generation and data acquisition.

    PubMed

    Avants, Benjamin W; Murphy, Daniel B; Dapello, Joel A; Robinson, Jacob T

    2015-01-01

    Patterned illumination using a digital micromirror device (DMD) is a powerful tool for optogenetics. Compared to a scanning laser, DMDs are inexpensive and can easily create complex illumination patterns. Combining these complex spatiotemporal illumination patterns with optogenetics allows DMD-equipped microscopes to probe neural circuits by selectively manipulating the activity of many individual cells or many subcellular regions at the same time. To use DMDs to study neural activity, scientists must develop specialized software to coordinate optical stimulation patterns with the acquisition of electrophysiological and fluorescence data. To meet this growing need we have developed an open source optical pattern generation software for neuroscience-NeuroPG-that combines, DMD control, sample visualization, and data acquisition in one application. Built on a MATLAB platform, NeuroPG can also process, analyze, and visualize data. The software is designed specifically for the Mightex Polygon400; however, as an open source package, NeuroPG can be modified to incorporate any data acquisition, imaging, or illumination equipment that is compatible with MATLAB's Data Acquisition and Image Acquisition toolboxes. PMID:25784873

  16. NeuroPG: open source software for optical pattern generation and data acquisition

    PubMed Central

    Avants, Benjamin W.; Murphy, Daniel B.; Dapello, Joel A.; Robinson, Jacob T.

    2015-01-01

    Patterned illumination using a digital micromirror device (DMD) is a powerful tool for optogenetics. Compared to a scanning laser, DMDs are inexpensive and can easily create complex illumination patterns. Combining these complex spatiotemporal illumination patterns with optogenetics allows DMD-equipped microscopes to probe neural circuits by selectively manipulating the activity of many individual cells or many subcellular regions at the same time. To use DMDs to study neural activity, scientists must develop specialized software to coordinate optical stimulation patterns with the acquisition of electrophysiological and fluorescence data. To meet this growing need we have developed an open source optical pattern generation software for neuroscience—NeuroPG—that combines, DMD control, sample visualization, and data acquisition in one application. Built on a MATLAB platform, NeuroPG can also process, analyze, and visualize data. The software is designed specifically for the Mightex Polygon400; however, as an open source package, NeuroPG can be modified to incorporate any data acquisition, imaging, or illumination equipment that is compatible with MATLAB’s Data Acquisition and Image Acquisition toolboxes. PMID:25784873

  17. Anomalous behavior in the radiation pattern of piezoelectric transducers induced by parasitic Lamb wave generation

    NASA Astrophysics Data System (ADS)

    Delannoy, B.; Bruneel, C.; Haine, F.; Torguet, R.

    1980-07-01

    In order to improve ultrasonic image quality, transducers, similar to those currently used in nondestructive testing and medical imaging applications, have been studied extensively. Attention has been given to single isolated transducers, for which anomalous radiation patterns have been obtained, and to transducers integrated in an array structure, where additional problems occur due to coupling effects between nearest neighbors. An experimental study of these phenomena has made it possible in both cases to find the origin of the perturbations with respect to the theoretical situations which occur in the radiation pattern. Solutions for increasing these perturbations are also suggested.

  18. Quantum Statistical Testing of a Quantum Random Number Generator

    SciTech Connect

    Humble, Travis S

    2014-01-01

    The unobservable elements in a quantum technology, e.g., the quantum state, complicate system verification against promised behavior. Using model-based system engineering, we present methods for verifying the opera- tion of a prototypical quantum random number generator. We begin with the algorithmic design of the QRNG followed by the synthesis of its physical design requirements. We next discuss how quantum statistical testing can be used to verify device behavior as well as detect device bias. We conclude by highlighting how system design and verification methods must influence effort to certify future quantum technologies.

  19. Effective hydrogen generator testing for on-site small engine

    NASA Astrophysics Data System (ADS)

    Chaiwongsa, Praitoon; Pornsuwancharoen, Nithiroth; Yupapin, Preecha P.

    2009-07-01

    We propose a new concept of hydrogen generator testing for on-site small engine. In general, there is a trade-off between simpler vehicle design and infrastructure issues, for instance, liquid fuels such as gasoline and methanol for small engine use. In this article we compare the hydrogen gases combination the gasoline between normal systems (gasoline only) for small engine. The advantage of the hydrogen combines gasoline for small engine saving the gasoline 25%. Furthermore, the new concept of hydrogen combination for diesel engine, bio-diesel engine, liquid petroleum gas (LPG), natural gas vehicle (NGV), which is discussed in details.

  20. International Space Station United States Oxygen Generator Development Testing

    NASA Technical Reports Server (NTRS)

    Erickson, Robert J.; Mason, Richard K.

    2000-01-01

    A life test of a liquid anode feed oxygen generator assembly (OGA) using SPE(R) (United Technologies Corporation, Hamilton Sundstrand Division) membrane technology was terminated in June of 1999. In the total 15,658 hours of operation at MSFC since delivery in 1995, the OGA has produced 2,103 kilograms (kg) (4,632 pounds mass (lbm)) of oxygen, and 263 kg (579 lbm) of hydrogen. Evaluation of cell stack characteristics and oxygen and hydrogen hydrophilic/hydrophobic membrane separators will be discussed.

  1. Strategies to modify the test-requesting patterns of clinicians.

    PubMed

    Fraser, C G; Woodford, F P

    1987-05-01

    Studies of the effectiveness of various strategies for influencing clinicians' test-requesting behaviour are reviewed. Numerical rationing, although crude, effectively reduces unnecessary repeat testing without detriment to patient outcome. Educational programmes involving peer review show pronounced but short-lived effects. Simple feedback of information about numbers of tests requested and their costs is surprisingly ineffectual. Direct financial incentives, in a private health care system, also failed. Clinical budgeting, of benefit in experimental trials, has yet to be widely tested, and the savings on reducing laboratory requesting may not be large enough to be attractive to clinicians. Agreed requesting policies in various specialties and clinical circumstances, endorsed by senior clinicians and prestigious professional bodies, seems a promising approach to more appropriate test requesting; further objective studies of their long-term effects are needed. Redesign of request forms into a problem-orientated format may be the simplest and most effective contribution by the laboratory; this strategy deserves further critical appraisal. PMID:3300513

  2. Radioisotope thermoelectric generator/thin fragment impact test

    NASA Astrophysics Data System (ADS)

    Reimus, M. A. H.; Hinckley, J. E.

    1998-01-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of 238Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system (PMS). The results of this test indicated that impact of the RTG by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the converter housing, failure of one fueled clad, and release of a small quantity of fuel.

  3. End-on radioisotope thermoelectric generator impact tests

    SciTech Connect

    Reimus, M.A.H.; Hhinckley, J.E.

    1997-01-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of [sup 238]Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). The modular GPHS design was developed to address both survivability during launch abort and return from orbit. The first two RTG Impact Tests were designed to provide information on the response of a fully loaded RTG to end-on impact against a concrete target. The results of these tests indicated that at impact velocities up to 57 m/s the converter shell and internal components protect the GPHS capsules from excessive deformation. At higher velocities, some of the internal components of the RTG interact with the GPHS capsules to cause excessive localized deformation and failure.

  4. Testing the Ability of TOPMODEL to Assess the Spatial Continuity and Connectivity of Soil Moisture Patterns

    NASA Astrophysics Data System (ADS)

    Ali, G.; Roy, A.

    2006-05-01

    Examining hydrologic connectivity as a major control on stormflow generation has emerged as an important field of research in forest hydrology. Knowledge on this new concept, however, has yet to be incorporated in most hydrological models and to be proven useful to simulate the "on-off" behaviour of small humid temperate catchments. In this study, we examine the hydrologic behaviour of a small headwater forested catchment, the Hermine, located in the Laurentians near Montreal, Quebec. This watershed is a textbook case for the application of the popular TOPMODEL. Still, the model does not perform well, especially following extended dry periods. Several explanations have been proposed regarding this issue, chiefly the existence of two or more preferential states and threshold-like processes associated with the spatio-temporal variations of antecedent moisture conditions (AMC). As these dominantly govern the initiation of stormflow, we test here the ability of the model to differentiate random patterns of soil moisture from organized ones. Using the topographic index distribution and the local storage deficit maps produced at each daily time step, the spatial correlation structure of potentially saturated areas and moisture conditions is studied through the use of geostatistical techniques. We also examine the methods of Western et al. (2001) in reference to the use of connectivity statistics to relate different soil moisture patterns with simulated hydrologic responses. From the spatial patterns of soil moisture simulated, TOPMODEL is capable of isolating several hydrologic preferential states, more or less wet with respect to a threshold value based on the mean catchment deficit. The changes in the disruption of spatial continuity of soil moisture are easier to identify when the correlation length among the patterns exhibits a high degree of seasonality. On the other hand, TOPMODEL falls short of representing some complex spatial patterns of disconnected saturated areas. These patterns require an explicit treatment of routing and connectivity, since hydrologically active zones based on the static topographic index are not representative of the "switching" nature of the response of the catchment. Solving this problem may require a new formulation of the topographic index, explicitly accounting for AMC, or a fully distributed version of TOPMODEL.

  5. Efficient second harmonic generation using nonlinear substrates patterned by nano-antenna arrays.

    PubMed

    Bar-Lev, Doron; Scheuer, Jacob

    2013-12-01

    We study theoretically various design considerations for efficient generation of second harmonic using a nonlinear substrate patterned with nano-antennas. The analysis is focused on a gap Bowtie nano-antenna array recessed in LiNbO? which is shown to be preferable over on surface structures due to field enhancement, field profile and linear and non-linear polarization considerations. In addition, we develop the nano-antenna counterpart of the Boyd-Klienmann model in order to analyze the impact of a Gaussian shaped fundamental beam on the generated second harmonic. Finally, we show that the dielectric properties of the substrate lead to preferable directions for the incident fundamental harmonic and the emission of the second harmonic. Our analyses lead to several design rules which can enhance second and high harmonic generation from nano-antennas arrays by several orders of magnitude. PMID:24514468

  6. Implementation of a Data Packet Generator Using Pattern Matching for Wearable ECG Monitoring Systems

    PubMed Central

    Noh, Yun Hong; Jeong, Do Un

    2014-01-01

    In this paper, a packet generator using a pattern matching algorithm for real-time abnormal heartbeat detection is proposed. The packet generator creates a very small data packet which conveys sufficient crucial information for health condition analysis. The data packet envelopes real time ECG signals and transmits them to a smartphone via Bluetooth. An Android application was developed specifically to decode the packet and extract ECG information for health condition analysis. Several graphical presentations are displayed and shown on the smartphone. We evaluate the performance of abnormal heartbeat detection accuracy using the MIT/BIH Arrhythmia Database and real time experiments. The experimental result confirm our finding that abnormal heart beat detection is practically possible. We also performed data compression ratio and signal restoration performance evaluations to establish the usefulness of the proposed packet generator and the results were excellent. PMID:25029280

  7. Diffraction patterns with mth order symmetry generated by sectional spiral phase plates

    NASA Astrophysics Data System (ADS)

    Khonina, S. N.; Porfirev, A. P.; Ustinov, A. V.

    2015-12-01

    The possibility of generating diffraction patterns with mth order symmetry when laser beams of different wavelengths illuminate sectional spiral phase plates (SPPs) is investigated analytically, numerically and experimentally. Such distributions are generated by a SPP with m sections in which the phase increases from 0 to 2? for the base wavelength. If the wavelength of laser light is changed, we get a decomposition of the mth order vortex beam into m off-axis vortices of the first order. We show that generating array of first-order optical vortices by the sectional SPPs can be dynamically controlled by the laser wavelength. Numerical simulation and experimental results are in a good agreement with the analytical calculations.

  8. Statistical spatial properties of speckle patterns generated by multiple laser beams

    SciTech Connect

    Le Cain, A.; Sajer, J. M.; Riazuelo, G.

    2011-08-15

    This paper investigates hot spot characteristics generated by the superposition of multiple laser beams. First, properties of speckle statistics are studied in the context of only one laser beam by computing the autocorrelation function. The case of multiple laser beams is then considered. In certain conditions, it is shown that speckles have an ellipsoidal shape. Analytical expressions of hot spot radii generated by multiple laser beams are derived and compared to numerical estimates made from the autocorrelation function. They are also compared to numerical simulations performed within the paraxial approximation. Excellent agreement is found for the speckle width as well as for the speckle length. Application to the speckle patterns generated in the Laser MegaJoule configuration in the zone where all the beams overlap is presented. Influence of polarization on the size of the speckles as well as on their abundance is studied.

  9. Implementation of a data packet generator using pattern matching for wearable ECG monitoring systems.

    PubMed

    Noh, Yun Hong; Jeong, Do Un

    2014-01-01

    In this paper, a packet generator using a pattern matching algorithm for real-time abnormal heartbeat detection is proposed. The packet generator creates a very small data packet which conveys sufficient crucial information for health condition analysis. The data packet envelopes real time ECG signals and transmits them to a smartphone via Bluetooth. An Android application was developed specifically to decode the packet and extract ECG information for health condition analysis. Several graphical presentations are displayed and shown on the smartphone. We evaluate the performance of abnormal heartbeat detection accuracy using the MIT/BIH Arrhythmia Database and real time experiments. The experimental result confirm our finding that abnormal heart beat detection is practically possible. We also performed data compression ratio and signal restoration performance evaluations to establish the usefulness of the proposed packet generator and the results were excellent. PMID:25029280

  10. A flight study of tone radiation patterns generated by inlet rods in a small turbofan engine

    NASA Technical Reports Server (NTRS)

    Preisser, J. S.; Silcox, R. J.; Eversman, W.; Parrett, A. V.

    1984-01-01

    This paper presents a flight study of tone radiation patterns from a small turbofan engine and compares results with similar static test stand data and a recently developed radiation theory. An interaction tone was produced by a circumferential array of inlet rods placed just upstream of the fan blades. Overhead and sideline flight directivity patterns showed cut-on of a dominant single mode occurred where predicted and the absence of any other significant circumferential or radial modes. In general, good agreement was found between measured flight and static data, with small differences being attributed to inlet geometry and/or forward speed effects. Good agreement was also obtained between flight data and theory for directivity pattern shape, however, the theory consistently predicted higher values for peak radiation angle over a wide range of frequency.

  11. Thermal vacuum life test facility for radioisotope thermoelectric generators

    NASA Astrophysics Data System (ADS)

    Deaton, R. L.; Goebel, C. J.; Amos, W. R.

    In the late 1970's, the Department of Energy (DOE) assigned Monsanto Research Corporation, Mound Facility, now operated by EG and G Mound Applied Technologies, the responsibility for assembling and testing General Purpose Heat Source (GPHS) radioisotope thermoelectric generators (RTGs). Assembled and tested were five RTGs, which included four flight units and one non-flight qualification unit. Figure 1 shows the RTG, which was designed by General Electric AstroSpace Division (GE/ASD) to produce 285 W of electrical power. A detailed description of the processes for RTG assembly and testing is presented by Amos and Goebel (1989). The RTG performance data are described by Bennett, et al., (1986). The flight units will provide electrical power for the National Aeronautics and Space Administration's (NASA) Galileo mission to Jupiter (two RTGs) and the joint NASA/European Space Agency (ESA) Ulysses mission to study the polar regions of the sun (one RTG). The remaining flight unit will serve as the spare for both missions, and a non-flight qualification unit was assembled and tested to ensure that performance criteria were adequately met.

  12. Thermal vacuum life test facility for radioisotope thermoelectric generators

    SciTech Connect

    Deaton, R.L.; Goebel, C.J.; Amos, W.R.

    1990-01-01

    In the late 1970's, the Department of Energy (DOE) assigned Monsanto Research Corporation, Mound Facility, now operated by EG G Mound Applied Technologies, the responsibility for assembling and testing General Purpose Heat Source (GPHS) radioisotope thermoelectric generators (RTGs). Assembled and tested were five RTGs, which included four flight units and one non-flight qualification unit. Figure 1 shows the RTG, which was designed by General Electric AstroSpace Division (GE/ASD) to produce 285 W of electrical power. A detailed description of the processes for RTG assembly and testing is presented by Amos and Goebel (1989). The RTG performance data are described by Bennett, et al. (1986). The flight units will provide electrical power for the National Aeronautics and Space Administration's (NASA) Galileo mission to Jupiter (two RTGs) and the joint NASA/European Space Agency (ESA) Ulysses mission to study the polar regions of the sun (one RTG). The remaining flight unit will serve as the spare for both missions, and a non-flight qualification unit was assembled and tested to ensure that performance criteria were adequately met. 4 refs., 3 figs.

  13. SMPTE Test Pattern For Certification Of Medical Diagnostic Display Devices

    NASA Astrophysics Data System (ADS)

    Lisk, Kenneth G.

    1984-08-01

    Since the invention of x-rays by Wilhelm Conrad Roentgen, rapid advances have been made in the radiological detection of body abnormalities. This was very evident in the 1960's and 70's when the marriage of computers to radiology gave birth to a new generation of imaging modalities such as computerized tomography, ultrasound, digital radiographic imaging, nuclear medicine, and nuclear magnetic resonance. Many of these devices employ digital computer techniques for signal manipulation, and the resultant analog diagnostic images are displayed on television monitors for viewing and on imaging cathode-ray tubes for a photographic hard copy.

  14. Mobile testing complex based on an explosive magnetic generator

    NASA Astrophysics Data System (ADS)

    Shurupov, A. V.; Kozlov, A. V.; Gusev, A. N.; Shurupova, N. P.; Zavalova, V. E.; Chulkov, A. N.; Bazelyan, E. M.

    2015-01-01

    A mobile testing complex prototype on the basis of an explosive magnetic generator (MTC EMG) is developed to simulate a lightning current pulse. The main element of this complex is a current pulse generator comprising a EMG with a pulse transformer for energy release into the load. The electric chain of the MTC EMG is theoretically analyzed taking into consideration energy losses in active resistances in the primary circuit of the transformer and the inductive-resistive nature of the load, which resulted in the minimization of energy losses in the primary circuit depending on the electric chain parameters. It was found that, if the energy losses are minimized, the efficiency of transferring the EMG energy into the load exceeds 50%. As a result of the field tests of the MTC EMG, its basic characteristics were determined and the waveforms of the current pulses and voltages in the load were obtained. It is shown that the results of the mathematical simulation of current pulses in the load are in good agreement with the experimental data.

  15. Design, fabrication, and testing of energy-harvesting thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Jovanovic, Velimir; Ghamaty, Saeid

    2006-03-01

    An energy-harvesting thermoelectric generator (TEG) is being developed to provide power for wireless sensors used in health monitoring of Navy machinery. TEGs are solid-state devices that convert heat directly into electricity without any moving parts. In this application, the TEGs utilize the heat transfer between shipboard waste heat sources and the ambient air to generate electricity. In order to satisfy the required small design volume of less than one cubic inch, Hi-Z is using its innovative thin-film Quantum Well (QW) thermoelectric technology that will provide a factor of four increase in efficiency and a large reduction in the device volume over the currently used bulk Bi IITe 3 based thermoelectics. QWs are nanostructured multi-layer films. These wireless sensors can be used to detect cracks, corrosion, impact damage, and temperature and vibration excursions as part of the Condition Based Maintenance (CBM) of the Navy ship machinery. The CBM of the ship machinery can be significantly improved by automating the process with the use of self-powered wireless sensors. These power-harvesting TEGs can be used to replace batteries as electrical power sources and to eliminate power cables and data lines. The first QW TEG module was fabricated and initial tests were successful. It is planned to conduct performance tests the entire prototype QW TEG device (consisting of the TEG module, housing, thermal insulation and the heat sink) in a simulated thermal environment of a Navy ship.

  16. Advanced E-O test capability for Army Next-Generation Automated Test System (NGATS)

    NASA Astrophysics Data System (ADS)

    Errea, S.; Grigor, J.; King, D. F.; Matis, G.; McHugh, S.; McKechnie, J.; Nehring, B.

    2015-05-01

    The Future E-O (FEO) program was established to develop a flexible, modular, automated test capability as part of the Next Generation Automatic Test System (NGATS) program to support the test and diagnostic needs of currently fielded U.S. Army electro-optical (E-O) devices, as well as being expandable to address the requirements of future Navy, Marine Corps and Air Force E-O systems. Santa Barbara infrared (SBIR) has designed, fabricated, and delivered three (3) prototype FEO for engineering and logistics evaluation prior to anticipated full-scale production beginning in 2016. In addition to presenting a detailed overview of the FEO system hardware design, features and testing capabilities, the integration of SBIR's EO-IR sensor and laser test software package, IRWindows 4™, into FEO to automate the test execution, data collection and analysis, archiving and reporting of results is also described.

  17. Toward robust phase-locking in Melibe swim central pattern generator models

    NASA Astrophysics Data System (ADS)

    Jalil, Sajiya; Allen, Dane; Youker, Joseph; Shilnikov, Andrey

    2013-12-01

    Small groups of interneurons, abbreviated by CPG for central pattern generators, are arranged into neural networks to generate a variety of core bursting rhythms with specific phase-locked states, on distinct time scales, which govern vital motor behaviors in invertebrates such as chewing and swimming. These movements in lower level animals mimic motions of organs in higher animals due to evolutionarily conserved mechanisms. Hence, various neurological diseases can be linked to abnormal movement of body parts that are regulated by a malfunctioning CPG. In this paper, we, being inspired by recent experimental studies of neuronal activity patterns recorded from a swimming motion CPG of the sea slug Melibe leonina, examine a mathematical model of a 4-cell network that can plausibly and stably underlie the observed bursting rhythm. We develop a dynamical systems framework for explaining the existence and robustness of phase-locked states in activity patterns produced by the modeled CPGs. The proposed tools can be used for identifying core components for other CPG networks with reliable bursting outcomes and specific phase relationships between the interneurons. Our findings can be employed for identifying or implementing the conditions for normal and pathological functioning of basic CPGs of animals and artificially intelligent prosthetics that can regulate various movements.

  18. Micropunching lithography for generating micro- and submicron-patterns on polymer substrates.

    PubMed

    Chakraborty, Anirban; Liu, Xinchuan; Luo, Cheng

    2012-01-01

    Conducting polymers have attracted great attention since the discovery of high conductivity in doped polyacetylene in 1977(1). They offer the advantages of low weight, easy tailoring of properties and a wide spectrum of applications(2,3). Due to sensitivity of conducting polymers to environmental conditions (e.g., air, oxygen, moisture, high temperature and chemical solutions), lithographic techniques present significant technical challenges when working with these materials(4). For example, current photolithographic methods, such as ultra-violet (UV), are unsuitable for patterning the conducting polymers due to the involvement of wet and/or dry etching processes in these methods. In addition, current micro/nanosystems mainly have a planar form(5,6). One layer of structures is built on the top surfaces of another layer of fabricated features. Multiple layers of these structures are stacked together to form numerous devices on a common substrate. The sidewall surfaces of the microstructures have not been used in constructing devices. On the other hand, sidewall patterns could be used, for example, to build 3-D circuits, modify fluidic channels and direct horizontal growth of nanowires and nanotubes. A macropunching method has been applied in the manufacturing industry to create macropatterns in a sheet metal for over a hundred years. Motivated by this approach, we have developed a micropunching lithography method (MPL) to overcome the obstacles of patterning conducting polymers and generating sidewall patterns. Like the macropunching method, the MPL also includes two operations (Fig. 1): (i) cutting; and (ii) drawing. The "cutting" operation was applied to pattern three conducting polymers(4), polypyrrole (PPy), Poly(3,4-ethylenedioxythiophen)-poly(4-styrenesulphonate) (PEDOT) and polyaniline (PANI). It was also employed to create Al microstructures(7). The fabricated microstructures of conducting polymers have been used as humidity(8), chemical(8), and glucose sensors(9). Combined microstructures of Al and conducting polymers have been employed to fabricate capacitors and various heterojunctions(9,10,11). The "cutting" operation was also applied to generate submicron-patterns, such as 100- and 500-nm-wide PPy lines as well as 100-nm-wide Au wires. The "drawing" operation was employed for two applications: (i) produce Au sidewall patterns on high density polyethylene (HDPE) channels which could be used for building 3D microsystems(12,13,14), and (ii) fabricate polydimethylsiloxane (PDMS) micropillars on HDPE substrates to increase the contact angle of the channel(15). PMID:22805740

  19. Micropunching Lithography for Generating Micro- and Submicron-patterns on Polymer Substrates

    PubMed Central

    Chakraborty, Anirban; Liu, Xinchuan; Luo, Cheng

    2012-01-01

    Conducting polymers have attracted great attention since the discovery of high conductivity in doped polyacetylene in 19771. They offer the advantages of low weight, easy tailoring of properties and a wide spectrum of applications2,3. Due to sensitivity of conducting polymers to environmental conditions (e.g., air, oxygen, moisture, high temperature and chemical solutions), lithographic techniques present significant technical challenges when working with these materials4. For example, current photolithographic methods, such as ultra-violet (UV), are unsuitable for patterning the conducting polymers due to the involvement of wet and/or dry etching processes in these methods. In addition, current micro/nanosystems mainly have a planar form5,6. One layer of structures is built on the top surfaces of another layer of fabricated features. Multiple layers of these structures are stacked together to form numerous devices on a common substrate. The sidewall surfaces of the microstructures have not been used in constructing devices. On the other hand, sidewall patterns could be used, for example, to build 3-D circuits, modify fluidic channels and direct horizontal growth of nanowires and nanotubes. A macropunching method has been applied in the manufacturing industry to create macropatterns in a sheet metal for over a hundred years. Motivated by this approach, we have developed a micropunching lithography method (MPL) to overcome the obstacles of patterning conducting polymers and generating sidewall patterns. Like the macropunching method, the MPL also includes two operations (Fig. 1): (i) cutting; and (ii) drawing. The "cutting" operation was applied to pattern three conducting polymers4, polypyrrole (PPy), Poly(3,4-ethylenedioxythiophen)-poly(4-styrenesulphonate) (PEDOT) and polyaniline (PANI). It was also employed to create Al microstructures7. The fabricated microstructures of conducting polymers have been used as humidity8, chemical8, and glucose sensors9. Combined microstructures of Al and conducting polymers have been employed to fabricate capacitors and various heterojunctions9,10,11. The "cutting" operation was also applied to generate submicron-patterns, such as 100- and 500-nm-wide PPy lines as well as 100-nm-wide Au wires. The "drawing" operation was employed for two applications: (i) produce Au sidewall patterns on high density polyethylene (HDPE) channels which could be used for building 3D microsystems12,13,14, and (ii) fabricate polydimethylsiloxane (PDMS) micropillars on HDPE substrates to increase the contact angle of the channel15. PMID:22805740

  20. Engineering systems for the generation of patterned co-cultures for controlling cell-cell interactions

    PubMed Central

    Kaji, Hirokazu; Camci-Unal, Gulden; Langer, Robert; Khademhosseini, Ali

    2010-01-01

    Background Inside the body, cells lie in direct contact or in close proximity to other cell types in a tightly controlled architecture that often regulates the resulting tissue function. Therefore, tissue engineering constructs that aim to reproduce the architecture and the geometry of tissues will benefit from methods of controlling cell–cell interactions with microscale resolution. Scope of the review We discuss the use of microfabrication technologies for generating patterned co-cultures. In addition, we categorize patterned co-culture systems by cell type and discuss the implications of regulating cell-cell interactions in the resulting biological function of the tissues. Major conclusions Patterned co-cultures are a useful tool for fabricating tissue engineered constructs and for studying cell–cell interactions in vitro, because they can be used to control the degree of homotypic and heterotypic cell–cell contact. In addition, this approach can be manipulated to elucidate important factors involved in cell-matrix interactions. General significance Patterned co-culture strategies hold significant potential to develop biomimetic structures for tissue engineering. It is expected that they would create opportunities to develop artificial tissues in the future. PMID:20655984

  1. A new touchscreen test of pattern separation: effect of hippocampal lesions.

    PubMed

    McTighe, Stephanie M; Mar, Adam C; Romberg, Carola; Bussey, Timothy J; Saksida, Lisa M

    2009-06-17

    Researchers are becoming increasingly interested in the role of the hippocampus in pattern separation, a process which keeps items distinct in memory. In this study, we develop and test a new automated touchscreen-based method for studying pattern separation in rodents. Rats were trained to discriminate locations on a computer screen that varied in their similarity, that is, their distance apart on the screen. Animals with lesions of the dorsal hippocampus were impaired when the locations discriminated were close together but not when they were far apart, indicating impaired pattern separation. This test provides an automated test of pattern separation, which adds to an expanding battery of cognitive tests that can be carried out using the touchscreen testing method. PMID:19421077

  2. Single Stage Contactor Testing Of The Next Generation Solvent Blend

    SciTech Connect

    Herman, D. T.; Peters, T. B.; Duignan, M. R.; Williams, M. R.; Poirier, M. R.; Brass, E. A.; Garrison, A. G.; Ketusky, E. T.

    2014-01-06

    The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility at the Savannah River Site (SRS) is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent to increase the cesium decontamination factor. To support this integration of NGS into the MCU facility the Savannah River National Laboratory (SRNL) performed testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing utilized a blend of BOBCalixC6 based solvent and the NGS with the new extractant, MaxCalix, as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 liquid-to-liquid centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. The results indicate that hydraulically, the NGS solvent performed hydraulically similar to the current solvent which was expected. For the organic carryover 93% of the solvent is predicted to be recovered from the stripping operation and 96% from the extraction operation. As for the mass transfer, the NGS solvent significantly improved the cesium DF by at least an order of magnitude when extrapolating the One-stage results to actual Seven-stage extraction operation with a stage efficiency of 95%.

  3. [Central Pattern Generators: Mechanisms of the Activity and Their Role in the Control of "Automatic" Movements].

    PubMed

    Arshavsky, I; Deliagina, T G; Orlovsky, G N

    2015-01-01

    Central pattern generators (CPGs) are a set of interconnected neurons capable of generating a basic pattern of motor output underlying "automatic" movements (breathing, locomotion, chewing, swallowing, and so on) in the absence of afferent signals from the executive motor apparatus. They can be divided into the constitutive CPGs active throughout the entire lifetime (respiratory CPGs) and conditional CPGs controlling episodic movements (locomotion, chewing, swallowing, and others). Since a motor output of CPGs is determined by their internal organization, the activities of the conditional CPGs are initiated by simple commands coming from higher centers. We describe the structural and functional organization of the locomotor CPGs in the marine mollusk Clione limacina, lamprey, frog embryo, and laboratory mammals (cat, mouse, and rat), CPGs controlling the respiratory and swallowing movements in mammals, and CPGs controlling discharges of the electric organ in the gymnotiform fish. It is shown that in all these cases, the generation of rhythmic motor output is based both on the endogenous (pacemaker) activity of specific groups of interneurons and on interneural interactions. These two interrelated mechanisms complement each other, ensuring the high reliability of CPG functionality. We discuss how the experience obtained in studying CPGs can be used to understand mechanisms of more complex functions of the brain, including its cognitive functions. PMID:26080596

  4. Convergence of pattern generator outputs on a common mechanism of diaphragm motor unit recruitment

    PubMed Central

    Mantilla, Carlos B.; Seven, Yasin B.; Sieck, Gary C.

    2014-01-01

    Motor units are the final element of neuromotor control. In manner analogous to the organization of neuromotor control in other skeletal muscles, diaphragm motor units comprise phrenic motoneurons located in the cervical spinal cord that innervate the diaphragm muscle, the main inspiratory muscle in mammals. Diaphragm motor units play a primary role in sustaining ventilation, but are also active in other non-ventilatory behaviors, including coughing, sneezing, vomiting, defecation and parturition. Diaphragm muscle fibers comprise all fiber types. Thus, diaphragm motor units display substantial differences in contractile and fatigue properties, but importantly properties of the motoneuron and muscle fibers within a motor unit are matched. As in other skeletal muscles, diaphragm motor units are recruited in order such that motor units that display greater fatigue resistance are recruited earlier and more often than more fatigable motor units. The properties of the motor unit population are critical determinants of the function of a skeletal muscle across the range of possible motor tasks. Accordingly, fatigue-resistant motor units are sufficient to generate the forces necessary for ventilatory behaviors whereas more fatigable units are only activated during expulsive behaviors important for airway clearance. Neuromotor control of diaphragm motor units may reflect selective inputs from distinct pattern generators distributed according to the motor unit properties necessary to accomplish these different motor tasks. In contrast, widely-distributed inputs to phrenic motoneurons from various pattern generators (e.g., for breathing, coughing or vocalization) would dictate recruitment order based on intrinsic electrophysiological properties. PMID:24746055

  5. Capacitive charge generation apparatus and method for testing circuits

    DOEpatents

    Cole, E.I. Jr.; Peterson, K.A.; Barton, D.L.

    1998-07-14

    An electron beam apparatus and method for testing a circuit are disclosed. The electron beam apparatus comprises an electron beam incident on an outer surface of an insulating layer overlying one or more electrical conductors of the circuit for generating a time varying or alternating current electrical potential on the surface; and a measurement unit connected to the circuit for measuring an electrical signal capacitively coupled to the electrical conductors to identify and map a conduction state of each of the electrical conductors, with or without an electrical bias signal being applied to the circuit. The electron beam apparatus can further include a secondary electron detector for forming a secondary electron image for registration with a map of the conduction state of the electrical conductors. The apparatus and method are useful for failure analysis or qualification testing to determine the presence of any open-circuits or short-circuits, and to verify the continuity or integrity of electrical conductors buried below an insulating layer thickness of 1-100 {micro}m or more without damaging or breaking down the insulating layer. The types of electrical circuits that can be tested include integrated circuits, multi-chip modules, printed circuit boards and flexible printed circuits. 7 figs.

  6. Capacitive charge generation apparatus and method for testing circuits

    DOEpatents

    Cole, Jr., Edward I. (Albuquerque, NM); Peterson, Kenneth A. (Albuquerque, NM); Barton, Daniel L. (Albuquerque, NM)

    1998-01-01

    An electron beam apparatus and method for testing a circuit. The electron beam apparatus comprises an electron beam incident on an outer surface of an insulating layer overlying one or more electrical conductors of the circuit for generating a time varying or alternating current electrical potential on the surface; and a measurement unit connected to the circuit for measuring an electrical signal capacitively coupled to the electrical conductors to identify and map a conduction state of each of the electrical conductors, with or without an electrical bias signal being applied to the circuit. The electron beam apparatus can further include a secondary electron detector for forming a secondary electron image for registration with a map of the conduction state of the electrical conductors. The apparatus and method are useful for failure analysis or qualification testing to determine the presence of any open-circuits or short-circuits, and to verify the continuity or integrity of electrical conductors buried below an insulating layer thickness of 1-100 .mu.m or more without damaging or breaking down the insulating layer. The types of electrical circuits that can be tested include integrated circuits, multi-chip modules, printed circuit boards and flexible printed circuits.

  7. SSME Seal Test Program: Test results for sawtooth pattern damper seal

    NASA Technical Reports Server (NTRS)

    Childs, D. W.

    1986-01-01

    Direct and transverse force coefficients for 11, sawtooth-pattern, and damper-seal configurations were examined. The designation damper seal uses a deliberately roughened stator and smooth rotor to increase the net damping force developed by a seal. The designation sawtooth-pattern refers to a stator roughness pattern. The sawtooth pattern yields axial grooves in the stator which are interrupted by spacer elements which act as flow constrictions or dams. All seals use the same smooth rotor and have the same, constant, minimum clearance. The stators examined the consequences of changes in the following design parameters: (1) axial-groove depth; (2) number of teeth: (3) number of sawtooth sections; (4) number of spacer elements; (5) dam width; (6) axially aligned sawtooth sections versus axially-staggered sawtooth sections; and (7) groove geometry. It is found that none of the sawtooth-pattern seal performs as well as the best round-hole-pattern seal. Maximum damping configurations for the sawtooth and round-hole-pattern stators have comparable stiffness performance. Several of the sawtooth pattern stators outperformed the best round-hole pattern seal.

  8. Distinct inspiratory rhythm and pattern generating mechanisms in the preBötzinger Complex

    PubMed Central

    Kam, Kaiwen; Worrell, Jason W.; Janczewski, Wiktor A.; Cui, Yan; Feldman, Jack L.

    2013-01-01

    In the mammalian respiratory central pattern generator, the preBötzinger Complex (preBötC) produces rhythmic bursts that drive inspiratory motor output. Cellular mechanisms initiated by each burst are hypothesized to be necessary to determine the timing of the subsequent burst, playing a critical role in rhythmogenesis. To explore mechanisms relating inspiratory burst generation to rhythmogenesis, we compared preBötC and hypoglossal (XII) nerve motor activity in medullary slices from neonatal mice in conditions where periods between successive inspiratory XII bursts were highly variable and distributed multimodally. This pattern resulted from rhythmic preBötC neural population activity that consisted of bursts, concurrent with XII bursts, intermingled with significantly smaller “burstlets”. Burstlets occurred at regular intervals during significantly longer XII interburst intervals, at times when a XII burst was expected. When a preBötC burst occurred, its high amplitude inspiratory component (I-burst) was preceded by a preinspiratory component that closely resembled the rising phase of burstlets. Cadmium (8 ?M) eliminated preBötC and XII bursts, but rhythmic preBötC burstlets persisted. Burstlets and preinspiratory activity were observed in ~90% of preBötC neurons that were active during I-bursts. When preBötC excitability was raised significantly, burstlets could leak through to motor output in medullary slices and in vivo in adult anesthetized rats. Thus, rhythmic bursting, a fundamental mode of nervous system activity and an essential element of breathing, can be deconstructed into a rhythmogenic process producing low amplitude burstlets and preinspiratory activity that determine timing, and a pattern-generating process producing suprathreshold I-bursts essential for motor output. PMID:23719793

  9. Precise colocalization of interacting structural and pigmentary elements generates extensive color pattern variation in Phelsuma lizards

    PubMed Central

    2013-01-01

    Background Color traits in animals play crucial roles in thermoregulation, photoprotection, camouflage, and visual communication, and are amenable to objective quantification and modeling. However, the extensive variation in non-melanic pigments and structural colors in squamate reptiles has been largely disregarded. Here, we used an integrated approach to investigate the morphological basis and physical mechanisms generating variation in color traits in tropical day geckos of the genus Phelsuma. Results Combining histology, optics, mass spectrometry, and UV and Raman spectroscopy, we found that the extensive variation in color patterns within and among Phelsuma species is generated by complex interactions between, on the one hand, chromatophores containing yellow/red pteridine pigments and, on the other hand, iridophores producing structural color by constructive interference of light with guanine nanocrystals. More specifically, we show that 1) the hue of the vivid dorsolateral skin is modulated both by variation in geometry of structural, highly ordered narrowband reflectors, and by the presence of yellow pigments, and 2) that the reflectivity of the white belly and of dorsolateral pigmentary red marks, is increased by underlying structural disorganized broadband reflectors. Most importantly, these interactions require precise colocalization of yellow and red chromatophores with different types of iridophores, characterized by ordered and disordered nanocrystals, respectively. We validated these results through numerical simulations combining pigmentary components with a multilayer interferential optical model. Finally, we show that melanophores form dark lateral patterns but do not significantly contribute to variation in blue/green or red coloration, and that changes in the pH or redox state of pigments provide yet another source of color variation in squamates. Conclusions Precisely colocalized interacting pigmentary and structural elements generate extensive variation in lizard color patterns. Our results indicate the need to identify the developmental mechanisms responsible for the control of the size, shape, and orientation of nanocrystals, and the superposition of specific chromatophore types. This study opens up new perspectives on Phelsuma lizards as models in evolutionary developmental biology. PMID:24099066

  10. On numerical turbulence generation for test-particle simulations

    SciTech Connect

    Tautz, R. C.; Dosch, A.

    2013-02-15

    A modified method is presented to generate artificial magnetic turbulence that is used for test-particle simulations. Such turbulent fields are obtained from the superposition of a set of wave modes with random polarizations and random directions of propagation. First, it is shown that the new method simultaneously fulfils requirements of isotropy, equal mean amplitude and variance for all field components, and vanishing divergence. Second, the number of wave modes required for a stochastic particle behavior is investigated by using a Lyapunov approach. For the special case of slab turbulence, it is shown that already for 16 wave modes the particle behavior agrees with that shown for considerably larger numbers of wave modes.

  11. TESTING OF THE SECOND GENERATION SPINTEK ROTARY FILTER -11357

    SciTech Connect

    Herman, D.; Poirier, M.; Fowley, M.; Keefer, M.; Huff, T.

    2011-02-02

    The SpinTek rotary microfilter has been developed under the Department of Energy (DOE) Office of Environmental Management (EM) for the purpose of deployment in radioactive service in the DOE complex. The unit that was fabricated and tested is the second generation of the filter that incorporates recommended improvements from previous testing. The completion of this test satisfied a key milestone for the EM technology development program and technology readiness for deployment by Savannah River Remediation in the Small Column Ion Exchange and Sludge Washing processes at the Savannah River Site (SRS). The Savannah River National Laboratory (SRNL) contracted SpinTek Filtration to fabricate a full scale 25 disk rotary filter and perform a 1000 hour endurance test with a simulated SRS sludge. Over 1500 hours of operation have been completed with the filter. SpinTek Filtration fabricated a prototypic 25 disk rotary filter including updates to manufacturing tolerances, an updated design to the rotary joint, improved cooling to the bottom journal, decreases in disk and filter shaft hydraulic resistances. The filter disks were fabricated with 0.5 {micro} pore size, sintered-metal filter media manufactured by Pall Corporation (M050). After fabrication was complete, the filter passed acceptance tests demonstrating rejection of solids and clean water flux with a 50% improvement over the previous filters. Once the acceptance test was complete, a 1000 hour endurance test was initiated simulating a sludge washing process. The test used a simulated SRS Sludge Batch 6 recipe. The insoluble solids started at 5 wt% and were raised to 10 and 15 wt% insoluble solids to simulate the concentration of a large volume tank. The filter system was automated and set up for 24 hour unattended operation. To facilitate this, process control logic was written to operate the filter. During the development it was demonstrated that the method of starting and stopping the filter can affect the build up of filter cake on the disks and therefore the performance of the filter. The filter performed well with the simulant. Very little drop in production was noticed between the 5 and 10 wt% insoluble solids feed. Increasing to 15 wt% had a more pronounced impact due to the rheology of the feed. Acid cleaning was used to clean the filter disks in-situ and restore filtration rate to almost 90% of the initial clean disk rate. Eighty liters of 0.2 M nitric acid in conjunction with water rinses were used to clean the filter in less than 2 hours. Filter testing was completed after 1000 hours of operation were performed on the final filter assembly configuration. The total run time for the testing was over 1500 hours. At the end of the test, the sludge washing was performed successfully from approximately 5.6 M to less than 1 M sodium.

  12. The Pattern Glare Test: a review and determination of normative values.

    PubMed

    Evans, B J W; Stevenson, S J

    2008-07-01

    Pattern glare is characterised by symptoms of visual perceptual distortions and visual stress on viewing striped patterns. People with migraine or Meares-Irlen syndrome (visual stress) are especially prone to pattern glare. The literature on pattern glare is reviewed, and the goal of this study was to develop clinical norms for the Wilkins and Evans Pattern Glare Test. This comprises three test plates of square wave patterns of spatial frequency 0.5, 3 and 12 cycles per degree (cpd). Patients are shown the 0.5 cpd grating and the number of distortions that are reported in response to a list of questions is recorded. This is repeated for the other patterns. People who are prone to pattern glare experience visual perceptual distortions on viewing the 3 cpd grating, and pattern glare can be quantified as either the sum of distortions reported with the 3 cpd pattern or as the difference between the number of distortions with the 3 and 12 cpd gratings, the '3-12 cpd difference'. In study 1, 100 patients consulting an optometrist performed the Pattern Glare Test and the 95th percentile of responses was calculated as the limit of the normal range. The normal range for the number of distortions was found to be <4 on the 3 cpd grating and <2 for the 3-12 cpd difference. Pattern glare was similar in both genders but decreased with age. In study 2, 30 additional participants were given the test in the reverse of the usual testing order and were compared with a sub-group from study 1, matched for age and gender. Participants experienced more distortions with the 12 cpd grating if it was presented after the 3 cpd grating. However, the order did not influence the two key measures of pattern glare. In study 3, 30 further participants who reported a medical diagnosis of migraine were compared with a sub-group of the participants in study 1 who did not report migraine or frequent headaches, matched for age and gender. The migraine group reported more symptoms on viewing all gratings, particularly the 3 cpd grating. The only variable to be significantly different between the groups was the 3-12 cpd difference. In conclusion, people have an abnormal degree of pattern glare if they have a Pattern Glare Test score of >3 on the 3 cpd grating or a score of >1 on the 3-12 cpd difference. The literature suggests that these people are likely to have visual stress in everyday life and may therefore benefit from interventions designed to alleviate visual stress, such as precision tinted lenses. PMID:18565084

  13. Bio-inspired Optimal Locomotion Reconfigurability of Quadruped Rovers using Central Pattern Generators

    NASA Astrophysics Data System (ADS)

    Bohra, Murtaza

    Legged rovers are often considered as viable solutions for traversing unknown terrain. This work addresses the optimal locomotion reconfigurability of quadruped rovers, which consists of obtaining optimal locomotion modes, and transitioning between them. A 2D sagittal plane rover model is considered based on a domestic cat. Using a Genetic Algorithm, the gait, pose and control variables that minimize torque or maximize speed are found separately. The optimization approach takes into account the elimination of leg impact, while considering the entire variable spectrum. The optimal solutions are consistent with other works on gait optimization, and are similar to gaits found in quadruped animals as well. An online model-free gait planning framework is also implemented, that is based on Central Pattern Generators is implemented. It is used to generate joint and control trajectories for any arbitrarily varying speed profile, and shown to regulate locomotion transition and speed modulation, both endogenously and continuously.

  14. The internal flow pattern analysis of a tidal power turbine operating on bidirectional generation-pumping

    NASA Astrophysics Data System (ADS)

    Y Luo, Y.; Xiao, Y. X.; Wang, Z. W.

    2013-12-01

    Using tidal energy can reduce environment pollution, save conventional energy and improve energy structure, hence it presents great advantage and is developing potential. Influenced by flood tide and low tide, a fully functional tidal power station needs to experience six operating modes, including bidirectional generation, pumping and sluice; the internal unsteady flow pattern and dynamic characters are very complicated. Based on a bidirectional tidal generator unit, three-dimensional unsteady flows in the flow path were calculated for four typical operating conditions with the pressure pulsation characteristics analyzed. According to the numerical results, the internal flow characteristics in the flow path were discussed. The influence of gravity to the hydraulic performance and flow characteristics were analysed. The results provide a theoretical analysis method of the hydraulic optimization design of the same type unit as well as a direction for stable operation and optimal scheduling of existing tidal power unit.

  15. Effects of glycinergic inhibition failure on respiratory rhythm and pattern generation.

    PubMed

    Shevtsova, Natalia A; Büsselberg, Dietrich; Molkov, Yaroslav I; Bischoff, Anne M; Smith, Jeffrey C; Richter, Diethelm W; Rybak, Ilya A

    2014-01-01

    Inhibitory interactions between neurons of the respiratory network are involved in rhythm generation and pattern formation. Using a computational model of brainstem respiratory networks, we investigated the possible effects of suppressing glycinergic inhibition on the activity of different respiratory neuron types. Our study revealed that progressive suppression of glycinergic inhibition affected all neurons of the network and disturbed neural circuits involved in termination of inspiration. Causal was a dysfunction of postinspiratory inhibition targeting inspiratory neurons, which often led to irregular preterm reactivation of these neurons, producing double or multiple short-duration inspiratory bursts. An increasing blockade of glycinergic inhibition led to apneustic inspiratory activity. Similar disturbances of glycinergic inhibition also occur during hypoxia. A clear difference in prolonged hypoxia, however, is that the rhythm terminates in expiratory apnea. The critical function of glycinergic inhibition for normal respiratory rhythm generation and the consequences of its reduction, including in pathological conditions, are discussed. PMID:24746041

  16. Numerical simulation of the ultrasonic waves generated by ring-shaped laser illumination patterns

    NASA Astrophysics Data System (ADS)

    Guan, Jianfei; Shen, Zhonghua; Ni, Xiaowu; Lu, Jian; Wang, Jijun; Xu, Baiqiang

    2007-09-01

    The generation of ultrasound in aluminum plate subjected to ring-shaped laser beam illumination has been studied quantitatively by using the finite element method. The superposition effects of surface acoustic waves on the top surface and the bulk ultrasonic waves on the rear surface of specimen have been obtained in a single simulation. The typical displacement profiles of the bulk ultrasonic wave at various depths along the central axis of the ring are obtained for three different radii, and the effect of the ring radius on the focal depths of the compression and shear mode are determined. The numerical results confirm that the focal depth of a bulk acoustic mode is determined by the directivity patterns of the acoustic mode generated by point-like laser sources via a thermoelastic mechanism, which depends on the physical constants of elastic medium.

  17. Fuel cell drive system with hydrogen generation in test

    NASA Astrophysics Data System (ADS)

    Emonts, B.; Bøgild Hansen, J.; Schmidt, H.; Grube, T.; Höhlein, B.; Peters, R.; Tschauder, A.

    In the future, drive systems for vehicles with polymer electrolyte membrane fuel cells (PEMFC) may be the environmentally more acceptable alternative to conventional drives with internal combustion engines. The energy carrier may not be gasoline or diesel, as in combustion engines today, but methanol, which is converted on-board into a hydrogen-rich synthesis gas in a reforming reaction with water. After removal of carbon monoxide in a gas-cleaning step, the conditioned synthesis gas is converted into electricity in a fuel cell using air as the oxidant. The electric energy thus generated serves to supply a vehicle's electric drive system. Based on the process design for a test drive system, a test facility was prepared and assembled at Forschungszentrum Jülich (FZJ). Final function tests with the PEMFC and the integrated compact methanol reformer (CMR) were carried out to determine the performance and the dynamic behaviour. With regard to the 50-kW(H 2)-compact methanol reformer, a special design of catalytic burner was constructed. The burner units, with a total power output of 16 kW, were built and tested under different states of constant and alternating load. If selecting a specific catalyst loading of 40 g Pt/m 2, the burner emissions are below the super ultra low emission vehicle (SULEV) standard. The stationary performance test of the CMR shows a specific hydrogen production of 6.7 m N3/(kg cat h) for a methanol conversion rate of 95% at 280°C. Measurements of the transient behaviour of the CMR clearly show a response time of about 20 s, reaching 99% of the hydrogen flow demand due to the limited performance of the test facility control system. Simulations have been carried out in order to develop a control strategy for hydrogen production by the CMR during the New European Driving Cycle (NEDC). Based on the NEDC, an optimized energy management for the total drive system was evaluated and the characteristic data for different peak load storage systems are described.

  18. An Experimental and Theoretical Study of Fracture Patterns Generated by Underground Explosions

    NASA Astrophysics Data System (ADS)

    Bhat, H.; Mihaly, J. M.; Rosakis, A.; Sammis, C. G.

    2012-12-01

    A dynamic micro-mechanical damage mechanics model, developed by Bhat, Rosakis and Sammis, J. Appl. Mech., 2012, is used to simulate two-dimensional explosions in a brittle material. The theoretical patterns of circumferential and radial fractures are quantitatively compared with those produced by point explosions in very brittle "candy glass" plates. In these experiments the evolution of the fracture pattern is monitored using high-speed digital photography, which also images the resultant elastic waves (P and S). Theoretical estimates of the spatial extent of circumferential and radial cracking as well as the propagation speed of the comminution front and the growth-rate of individual radial cracks all compare well with the experimental observations. The wave-forms of the P and S waves, specifically the local particle velocities, are also recorded at selected points using laser vibrometers. Asymmetric fracture patterns caused by a non isotropic pre-stress, the preferred orientation of initial flaws (a rift plane), or a lithostatic gradient lead to the generation of strong S-waves from the otherwise spherically symmetric point source.

  19. Central pattern generators for social vocalization: Androgen-dependent neurophysiological mechanisms

    PubMed Central

    Bass, Andrew H.; Remage-Healey, Luke

    2008-01-01

    Historically, most studies of vertebrate central pattern generators (CPGs) have focused on mechanisms for locomotion and respiration. Here, we highlight new results for ectothermic vertebrates, namely teleost fish and amphibians, showing how androgenic steroids can influence the temporal patterning of CPGs for social vocalization. Investigations of vocalizing teleosts show how androgens can rapidly (within minutes) modulate the neurophysiological output of the vocal CPG (fictive vocalizations that mimic the temporal properties of natural vocalizations) inclusive of their divergent actions between species, as well as intraspecific differences between male reproductive morphs. Studies of anuran amphibians (frogs) demonstrate that long-term steroid treatments (wks) can masculinize the fictive vocalizations of females, inclusive of its sensitivity to rapid modulation by serotonin. Given the conserved organization of vocal control systems across vertebrate groups, the vocal CPGs of fish and amphibians provide tractable models for identifying androgen-dependent events that are fundamental to the mechanisms of vocal motor patterning. These basic mechanisms can also inform our understanding of the more complex CPGs for vocalization, and social behaviors in general, that have evolved among birds and mammals. PMID:18262186

  20. Central pattern generators for social vocalization: androgen-dependent neurophysiological mechanisms.

    PubMed

    Bass, Andrew H; Remage-Healey, Luke

    2008-05-01

    Historically, most studies of vertebrate central pattern generators (CPGs) have focused on mechanisms for locomotion and respiration. Here, we highlight new results for ectothermic vertebrates, namely teleost fish and amphibians, showing how androgenic steroids can influence the temporal patterning of CPGs for social vocalization. Investigations of vocalizing teleosts show how androgens can rapidly (within minutes) modulate the neurophysiological output of the vocal CPG (fictive vocalizations that mimic the temporal properties of natural vocalizations) inclusive of their divergent actions between species, as well as intraspecific differences between male reproductive morphs. Studies of anuran amphibians (frogs) demonstrate that long-term steroid treatments (wks) can masculinize the fictive vocalizations of females, inclusive of its sensitivity to rapid modulation by serotonin. Given the conserved organization of vocal control systems across vertebrate groups, the vocal CPGs of fish and amphibians provide tractable models for identifying androgen-dependent events that are fundamental to the mechanisms of vocal motor patterning. These basic mechanisms can also inform our understanding of the more complex CPGs for vocalization, and social behaviors in general, that have evolved among birds and mammals. PMID:18262186

  1. Fast oscillations during gasping and other non-eupneic respiratory behaviors: Clues to central pattern generation.

    PubMed

    Ghali, Michael George Zaki; Marchenko, Vitaliy

    2013-06-15

    The mammalian nervous system exhibits fast synchronous oscillations, which are especially prominent in respiratory-related nerve discharges. In the phrenic nerve, they include high- (HFO), medium- (MFO), and low-frequency (LFO) oscillations. Because motoneurons firing at HFO-related frequencies had never been recorded, an epiphenomenological mechanism for their existence had been posited. We have recently recorded phrenic motoneurons firing at HFO-related frequencies in unanesthetized decerebrate rats and showed that they exhibit dynamic coherence with the phrenic nerve, validating synchronous motoneuronal discharge as a mechanism underlying the generation of HFO. In so doing, we have helped validate the conclusions of previous studies by us and other investigators who have used changes in fast respiratory oscillations to make inferences about central respiratory pattern generation. Here, we seek to review changes occurring in fast synchronous oscillations during non-eupneic respiratory behaviors, with special emphasis on gasping, and the inferences that can be drawn from these dynamics regarding respiratory pattern formation. PMID:23545119

  2. Control of traveling-wave oscillations and bifurcation behavior in central pattern generators

    NASA Astrophysics Data System (ADS)

    Landsman, Alexandra S.; Slotine, Jean-Jacques

    2012-10-01

    Understanding synchronous and traveling-wave oscillations, particularly as they relate to transitions between different types of behavior, is a central problem in modeling biological systems. Here, we address this problem in the context of central pattern generators (CPGs). We use contraction theory to establish the global stability of a traveling-wave or synchronous oscillation, determined by the type of coupling. This opens the door to better design of coupling architectures to create the desired type of stable oscillations. We then use coupling that is both amplitude and phase dependent to create either globally stable synchronous or traveling-wave solutions. Using the CPG motor neuron network of a leech as an example, we show that while both traveling and synchronous oscillations can be achieved by several types of coupling, the transition between different types of behavior is dictated by a specific coupling architecture. In particular, it is only the “repulsive” but not the commonly used phase or rotational coupling that can explain the transition to high-frequency synchronous oscillations that have been observed in the heartbeat pattern generator of a leech. This shows that the overall dynamics of a CPG can be highly sensitive to the type of coupling used, even for coupling architectures that are widely believed to produce the same qualitative behavior.

  3. Organisation of the spinal central pattern generators for locomotion in the salamander: biology and modelling.

    PubMed

    Chevallier, Stéphanie; Jan Ijspeert, Auke; Ryczko, Dimitri; Nagy, Frédéric; Cabelguen, Jean-Marie

    2008-01-01

    Among living tetrapods, salamanders are regarded as most closely resembling the first terrestrial vertebrates, and are therefore an interesting group in which the evolutionary changes in the locomotor behaviour from aquatic to terrestrial habitats can be inferred. Salamanders exhibit two locomotor modes: swimming and terrestrial stepping. The swimming is anguilliform and resembles closely that of the lamprey. On the ground, the salamander switches to a stepping gait with axial undulations that is also observed in many reptiles. The salamander is therefore ideally suited for examining the neural mechanisms for the generation of these two locomotor modes, as well as the neural mechanisms of gait transition. In the present paper, we describe the kinematics and patterns of activation of axial and limb muscles during stepping and swimming in adult salamanders. We then review the current neurobiological data about the organisation of the spinal networks underlying swimming and stepping, and the mechanisms of gait transition. Finally we report modelling studies aimed at understanding the organisation and operation of the salamander locomotor circuits. Altogether, the neurobiological and the modelling data support the hypothesis of a phylogenetic conservatism from agnathians to amphibians of the spinal locomotor networks generating axial motor patterns. PMID:17920689

  4. Resolution improvement and pattern generator development for the maskless micro-ion-beam reduction lithography system

    NASA Astrophysics Data System (ADS)

    Jiang, Ximan

    The shrinking of IC devices has followed the Moore's Law for over three decades, which states that the density of transistors on integrated circuits will double about every two years. This great achievement is obtained via continuous advance in lithography technology. With the adoption of complicated resolution enhancement technologies, such as the phase shifting mask (PSM), the optical proximity correction (OPC), optical lithography with wavelength of 193 nm has enabled 45 nm printing by immersion method. However, this achievement comes together with the skyrocketing cost of masks, which makes the production of low volume application-specific IC (ASIC) impractical. In order to provide an economical lithography approach for low to medium volume advanced IC fabrication, a maskless ion beam lithography method, called Maskless Micro-ion-beam Reduction Lithography (MMRL), has been developed in the Lawrence Berkeley National Laboratory. The development of the prototype MMRL system has been described by Dr. Vinh Van Ngo in his Ph.D. thesis. But the resolution realized on the prototype MMRL system was far from the design expectation. In order to improve the resolution of the MMRL system, the ion optical system has been investigated. By integrating a field-free limiting aperture into the optical column, reducing the electromagnetic interference and cleaning the RF plasma, the resolution has been improved to around 50 nm. Computational analysis indicates that the MMRL system can be operated with an exposure field size of 0.25 mm and a beam half angle of 1.0 mrad on the wafer plane. Ion-ion interactions have been studied with a two-particle physics model. The results are in excellent agreement with those published by the other research groups. The charge-interaction analysis of MMRL shows that the ion-ion interactions must be reduced in order to obtain a throughput higher than 10 wafers per hour on 300-mm wafers. In addition, two different maskless lithography strategies have been studied. The dependence of the throughput with the exposure field size and the speed of the mechanical stage has been investigated. In order to perform maskless lithography, different micro-fabricated pattern generators have been developed for the MMRL system. Ion beamlet switching has been successfully demonstrated on the MMRL system. A positive bias voltage around 10 volts is sufficient to switch off the ion current on the micro-fabricated pattern generators. Some unexpected problems, such as the high-energy secondary electron radiations, have been discovered during the experimental investigation. Thermal and structural analysis indicates that the aperture displacement error induced by thermal expansion can satisfy the 3delta CD requirement for lithography nodes down to 25 nm. The cross-talking effect near the surface and inside the apertures of the pattern generator has been simulated in a 3-D ray-tracing code. New pattern generator design has been proposed to reduce the cross-talking effect. In order to eliminate the surface charging effect caused by the secondary electrons, a new beam-switching scheme in which the switching electrodes are immersed in the plasma has been demonstrated on a mechanically fabricated pattern generator.

  5. Entropy Generation/Availability Energy Loss Analysis Inside MIT Gas Spring and "Two Space" Test Rigs

    NASA Technical Reports Server (NTRS)

    Ebiana, Asuquo B.; Savadekar, Rupesh T.; Patel, Kaushal V.

    2006-01-01

    The results of the entropy generation and availability energy loss analysis under conditions of oscillating pressure and oscillating helium gas flow in two Massachusetts Institute of Technology (MIT) test rigs piston-cylinder and piston-cylinder-heat exchanger are presented. Two solution domains, the gas spring (single-space) in the piston-cylinder test rig and the gas spring + heat exchanger (two-space) in the piston-cylinder-heat exchanger test rig are of interest. Sage and CFD-ACE+ commercial numerical codes are used to obtain 1-D and 2-D computer models, respectively, of each of the two solution domains and to simulate the oscillating gas flow and heat transfer effects in these domains. Second law analysis is used to characterize the entropy generation and availability energy losses inside the two solution domains. Internal and external entropy generation and availability energy loss results predicted by Sage and CFD-ACE+ are compared. Thermodynamic loss analysis of simple systems such as the MIT test rigs are often useful to understand some important features of complex pattern forming processes in more complex systems like the Stirling engine. This study is aimed at improving numerical codes for the prediction of thermodynamic losses via the development of a loss post-processor. The incorporation of loss post-processors in Stirling engine numerical codes will facilitate Stirling engine performance optimization. Loss analysis using entropy-generation rates due to heat and fluid flow is a relatively new technique for assessing component performance. It offers a deep insight into the flow phenomena, allows a more exact calculation of losses than is possible with traditional means involving the application of loss correlations and provides an effective tool for improving component and overall system performance.

  6. NIH Toolbox Cognitive Battery (NIHTB-CB): the NIHTB Pattern Comparison Processing Speed Test.

    PubMed

    Carlozzi, Noelle E; Tulsky, David S; Chiaravalloti, Nancy D; Beaumont, Jennifer L; Weintraub, Sandra; Conway, Kevin; Gershon, Richard C

    2014-07-01

    The NIH Toolbox (NIHTB) Pattern Comparison Processing Speed Test was developed to assess processing speed within the NIHTB for the Assessment of Neurological Behavior and Function Cognition Battery (NIHTB-CB). This study highlights validation data collected in adults ages 18-85 on this measure and reports descriptive data, test-retest reliability, construct validity, and preliminary work creating a composite index of processing speed. Results indicated good test-retest reliability. There was also evidence for both convergent and discriminant validity; the Pattern Comparison Processing Speed Test demonstrated moderate significant correlations with other processing speed tests (i.e., WAIS-IV Coding, Symbol Search and Processing Speed Index), small significant correlations with measures of working memory (i.e., WAIS-IV Letter-Number Sequencing and PASAT), and non-significant correlations with a test of vocabulary comprehension (i.e., PPVT-IV). Finally, analyses comparing and combining scores on the NIHTB Pattern Comparison Processing Speed Test with other measures of simple reaction time from the NIHTB-CB indicated that a Processing Speed Composite score performed better than any test examined in isolation. The NIHTB Pattern Comparison Processing Speed Test exhibits several strengths: it is appropriate for use across the lifespan (ages, 3-85 years), it is short and easy to administer, and it has high construct validity. PMID:24960594

  7. Directivity patterns of ultrasonic waves generated by a laser pulse at the interface between two elastic media

    NASA Astrophysics Data System (ADS)

    Anagnostopoulos, E.; Ségur, D.; Dehoux, T.; Audoin, B.

    2016-02-01

    Directivity patterns of an acoustic source generated by the absorption of a laser pulse at the interface between a transparent epoxy-resin half-space and an opaque CFRP isotropised half-space have been calculated using the reciprocity theorem. Longitudinal and shear radiation patterns of acoustic field emitted in the CFRP are compared in respect with the loading surface condition.

  8. GENERIC VERIFICATION PROTOCOL: DISTRIBUTED GENERATION AND COMBINED HEAT AND POWER FIELD TESTING PROTOCOL

    EPA Science Inventory

    This report is a generic verification protocol by which EPA’s Environmental Technology Verification program tests newly developed equipment for distributed generation of electric power, usually micro-turbine generators and internal combustion engine generators. The protocol will ...

  9. GENERIC VERIFICATION PROTOCOL: DISTRIBUTED GENERATION AND COMBINED HEAT AND POWER FIELD TESTING PROTOCOL

    EPA Science Inventory

    This report is a generic verification protocol by which EPA’s Environmental Technology Verification program tests newly developed equipment for distributed generation of electric power, usually micro-turbine generators and internal combustion engine generators. The protocol will ...

  10. Enhancing Students' Learning Process Through Self-Generated Tests

    NASA Astrophysics Data System (ADS)

    Sanchez-Elez, Marcos; Pardines, Inmaculada; Garcia, Pablo; Miñana, Guadalupe; Roman, Sara; Sanchez, Margarita; Risco, Jose Luis

    2013-03-01

    The use of new technologies in higher education has surprisingly emphasized students' tendency to adopt a passive behavior in class. Participation and interaction of students are essential to improve academic results. This paper describes an educational experiment aimed at the promotion of students' autonomous learning by requiring them to generate test type questions related to the contents of the course. The main idea is to make the student feel part of the evaluation process by including students' questions in the evaluation exams. A set of applications running on our university online learning environment has been developed in order to provide both students and teachers with the necessary tools for a good interaction between them. Questions uploaded by students are visible to every enrolled student as well as to each involved teacher. In this way, we enhance critical analysis skills, by solving and finding possible mistakes in the questions sent by their fellows. The experiment was applied over 769 students from 12 different courses. Results show that the students who have actively participated in the experiment have obtained better academic performance.

  11. A products generator for testing the performance of disassembly procedures

    NASA Astrophysics Data System (ADS)

    Adenso-Díaz, Belarmino; González Torre, Beatriz

    2004-12-01

    In recent decades, regulations and markets have been exerting pressure on designers and manufacturers to take more responsibility for the environmental impacts of their products throughout their life cycles. The problem of finding the disassembly sequence represents one of the major challenges when attempting to close product life cycles by carrying out reuse, recycling and remanufacturing practices. Many different techniques have been used to deal with this problem, varying from exact to heuristic solutions. So far, however, not much effort has gone into measuring and comparing the efficiency of this wide set of techniques. This is partly due to the difficulties of getting a wide population of real products, belonging to different industries and with different degree of complexity that might constitute a representative population for carrying out this kind of task. In this paper, a generator of complex products is presented that is able to build up products with hundreds of components joined by different kinds of joints in such a way that a theoretical "good" disassembly sequence is always known. The efficiency of different methods for general products can thus be easily compared. The performance of a Scatter Search algorithm is tested as an example of its application in this case.

  12. An Efficient Functional Test Generation Method For Processors Using Genetic Algorithms

    NASA Astrophysics Data System (ADS)

    Hudec, Ján; Gramatová, Elena

    2015-07-01

    The paper presents a new functional test generation method for processors testing based on genetic algorithms and evolutionary strategies. The tests are generated over an instruction set architecture and a processor description. Such functional tests belong to the software-oriented testing. Quality of the tests is evaluated by code coverage of the processor description using simulation. The presented test generation method uses VHDL models of processors and the professional simulator ModelSim. The rules, parameters and fitness functions were defined for various genetic algorithms used in automatic test generation. Functionality and effectiveness were evaluated using the RISC type processor DP32.

  13. Bayesian Procedures for Identifying Aberrant Response-Time Patterns in Adaptive Testing

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Guo, Fanmin

    2008-01-01

    In order to identify aberrant response-time patterns on educational and psychological tests, it is important to be able to separate the speed at which the test taker operates from the time the items require. A lognormal model for response times with this feature was used to derive a Bayesian procedure for detecting aberrant response times.…

  14. Bayesian Procedures for Identifying Aberrant Response-Time Patterns in Adaptive Testing

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Guo, Fanmin

    2008-01-01

    In order to identify aberrant response-time patterns on educational and psychological tests, it is important to be able to separate the speed at which the test taker operates from the time the items require. A lognormal model for response times with this feature was used to derive a Bayesian procedure for detecting aberrant response times.…

  15. A Psychometric Review of Norm-Referenced Tests Used to Assess Phonological Error Patterns

    ERIC Educational Resources Information Center

    Kirk, Celia; Vigeland, Laura

    2014-01-01

    Purpose: The authors provide a review of the psychometric properties of 6 norm-referenced tests designed to measure children's phonological error patterns. Three aspects of the tests' psychometric adequacy were evaluated: the normative sample, reliability, and validity. Method: The specific criteria used for determining the psychometric…

  16. A motion artifact generation and assessment system for the rapid testing of surface biopotential electrodes.

    PubMed

    Cömert, Alper; Hyttinen, Jari

    2015-01-01

    Dry electrodes can reduce cost while increasing the usability and comfort of wearable monitoring systems. They are, however, susceptible to motion artifacts. The present electrode testing methods lack reliability and do not separate the factors that affect the motion artifact. In this paper, we introduce a first generation motion artifact generation and assessment system that generates the speed, amplitude, and pattern-wise programmable movement of the electrode. The system simultaneously measures electrode-skin impedance, the motion artifact, and one channel of an electrocardiogram that contains the motion artifact and monitors the mounting force applied to the electrode. We demonstrate the system by comparing the applied movement and the measured signals for electrode movements up to 6 mm and movement frequencies from 0.4 Hz to 4 Hz. Results show that the impedance change and surface potential are visually clearly related to the applied motion, with average correlations of 0.89 and 0.64, respectively. The applied force, electrode location, and electrode structure all affect the motion artifact. The setup enables the motion of the electrode to be accurately controlled. The system can be used as a precursor to the testing of integrated systems because it enables thorough, repeatable, and robust motion artifact studies. The system allows a deeper insight into motion artifacts and the interplay of the various factors that affect them. PMID:25500614

  17. The Generation of Experimental Data for Computational Testing in Optimization

    NASA Astrophysics Data System (ADS)

    Hall, Nicholas G.; Posner, Marc E.

    This chapter discusses approaches to generating synthetic data for use in scientific experiments. In many diverse scientific fields, the lack of availability, high cost or inconvenience of the collection of real-world data motivates the generation of synthetic data. In many experiments, the method chosen to generate synthetic data can significantly affect the results of an experiment. Unfortunately, the scientific literature does not contain general protocols for how synthetic data should be generated. The purpose of this chapter is to rectify that deficiency. The protocol we propose is based on several generation principles. These principles motivate and organize the data generation process. The principles are operationalized by generation properties. Then, together with information about the features of the application and of the experiment, the properties are used to construct a data generation scheme. Finally, we suggest procedures for validating the synthetic data generated. The usefulness of our protocol is illustrated by a discussion of numerous applications of data generation from the optimization literature. This discussion identifies examples of both good and bad data generation practice as it relates to our protocol.

  18. Emergent Central Pattern Generator Behavior in Gap-Junction-Coupled Hodgkin-Huxley Style Neuron Model

    PubMed Central

    Memelli, Heraldo; Solomon, Irene C.

    2012-01-01

    Most models of central pattern generators (CPGs) involve two distinct nuclei mutually inhibiting one another via synapses. Here, we present a single-nucleus model of biologically realistic Hodgkin-Huxley neurons with random gap junction coupling. Despite no explicit division of neurons into two groups, we observe a spontaneous division of neurons into two distinct firing groups. In addition, we also demonstrate this phenomenon in a simplified version of the model, highlighting the importance of afterhyperpolarization currents (IAHP) to CPGs utilizing gap junction coupling. The properties of these CPGs also appear sensitive to gap junction conductance, probability of gap junction coupling between cells, topology of gap junction coupling, and, to a lesser extent, input current into our simulated nucleus. PMID:23365558

  19. Reticular activating system of a central pattern generator: premovement electrical potentials

    PubMed Central

    Tapia, Jesus A; Trejo, Argelia; Linares, Pablo; Alva, J Manuel; Kristeva, Rumyana; Manjarrez, Elias

    2013-01-01

    For the first time, here we characterize a bulbar reticular activating system (RAS) of neurons in decerebrate, deafferented and decerebellated cats producing a premovement electrical potential that we named obex slow potential (OSP). The OSP occurs about 0.8 ± 0.4 sec prior to the onset of a fictive-scratching-episode. Here, we describe two classes of bulbar neurons, off-on, which are silent but exhibit a 80 ± 56 Hz firing discharge at the beginning of (and during) the OSP, and on-off interneurons, with a 27 ± 14 Hz firing activity that stops at the beginning of (and during) the OSP. We suggest that these OSP-associated neurons belong to a descending RAS, which contributes to the activation of the spinal central pattern generators. PMID:24303193

  20. [Study on the control of dynamic artificial limb ankle based on central pattern generator].

    PubMed

    Guo, Xin; Xu, Caiyu; Li, Mingyue; Su, Longtao

    2014-12-01

    In order to obtain the normal gait for the prosthesis-carrier with the change of external environment and gait, we designed a model of dynamic ankle prosthesis and control system and introduced the strategy of central pattern generator (CPG) about the moving trail of dynamic ankle prosthesis. The dynamic parts, which are incorporated in the model of dynamic ankle prosthesis, provide power in order to have anthropic function and character. The tool of Matlab/simulink was used to simulate the strategy. The simulation results showed that the strategy of CPG learn- ing control in this study was effective and could track the reference trail rapidly and fit the moving trail of a person's normal limb. It can make the prosthetic timely regulation and action, enhance the prosthetic intelligence. It has im- portant practical value for intelligent prosthesis development based on this analysis of technology. PMID:25868262

  1. On the search for the vocal pattern generator. A single-unit recording study.

    PubMed

    Düsterhöft, F; Häusler, U; Jürgens, U

    2000-06-26

    In the squirrel monkey (Saimiri sciureus), single-unit activity was compared between the midbrain periaqueductal grey and the parvocellular and central nuclei of the medullary reticular formation during the production of species-specific vocalization. It was found that all three areas contain neurones with vocalization-related activity. The relative number of specific reactions types differed between areas, however. While the majority of periaqueductal cells fired just before, but not during vocalization, most cells in the reticular formation fired before and during vocalization. Modulation of discharge rate with changing fundamental frequency was only found in the reticular formation, not the periaqueductal grey. It is concluded that the parvocellular and central nuclei of the reticular formation, but not the periaqueductal grey are involved in vocal pattern generation. PMID:10884066

  2. On the derivation and tuning of phase oscillator models for lamprey central pattern generators.

    PubMed

    Várkonyi, Péter L; Kiemel, Tim; Hoffman, Kathleen; Cohen, Avis H; Holmes, Philip

    2008-10-01

    Using phase response curves and averaging theory, we derive phase oscillator models for the lamprey central pattern generator from two biophysically-based segmental models. The first one relies on network dynamics within a segment to produce the rhythm, while the second contains bursting cells. We study intersegmental coordination and show that the former class of models shows more robust behavior over the animal's range of swimming frequencies. The network-based model can also easily produce approximately constant phase lags along the spinal cord, as observed experimentally. Precise control of phase lags in the network-based model is obtained by varying the relative strengths of its six different connection types with distance in a phase model with separate coupling functions for each connection type. The phase model also describes the effect of randomized connections, accurately predicting how quickly random network-based models approach the determinisitic model as the number of connections increases. PMID:18266097

  3. Cell polarity-driven instability generates self-organized, fractal patterning of cell layers.

    PubMed

    Rudge, Timothy J; Federici, Fernán; Steiner, Paul J; Kan, Anton; Haseloff, Jim

    2013-12-20

    As a model system to study physical interactions in multicellular systems, we used layers of Escherichia coli cells, which exhibit little or no intrinsic coordination of growth. This system effectively isolates the effects of cell shape, growth, and division on spatial self-organization. Tracking the development of fluorescence-labeled cellular domains, we observed the emergence of striking fractal patterns with jagged, self-similar shapes. We then used a large-scale, cellular biophysical model to show that local instabilities due to polar cell-shape, repeatedly propagated by uniaxial growth and division, are responsible for generating this fractal geometry. Confirming this result, a mutant of E. coli with spherical shape forms smooth, nonfractal cellular domains. These results demonstrate that even populations of relatively simple bacterial cells can possess emergent properties due to purely physical interactions. Therefore, accurate physico-genetic models of cell growth will be essential for the design and understanding of genetically programmed multicellular systems. PMID:23688051

  4. Diversity of wing patterns and abdomen-generated substrate sounds in 3 European scorpionfly species.

    PubMed

    Hartbauer, Manfred; Gepp, Johannes; Hinteregger, Karin; Koblmüller, Stephan

    2015-08-01

    In the genus Panorpa (Insecta: Mecoptera), also known as scorpionflies, premating behavior includes repeated sequences of slow wing movements (waving, fanning, flagging) which are accompanied by rapid abdomen vibrations that generate substantial substrate-borne sound. It is still unknown whether wing patterns or vibratory signals contain information about species identity, sex and/or the quality of potential mating partners. Besides species-specific pheromones, these multimodal signals may be of particular importance for the maintenance of reproductive isolation in sympatrically occurring scorpionfly species. Here, we analyzed phyologenetic relationships among, and the pattern of forewings as well as substrate-borne sound in 3 different sympatric Central-European scorpionfly species (P. communis, P. germanica, and P. alpina). Divergence time estimates, based on 879?bp of the mitochondrial COI gene, indicate longstanding separate evolutionary histories for the studied Panorpa species. Morphological analysis revealed that wing length as an indicator of body size increased in the following order: P. alpina < P. germanica < P. communis. Individuals can be assigned to the correct species and sex with high accuracy just by evaluation of the number of dark spots and the proportion of wing pigmentation. Despite high variability of interpulse period at an individual level, across species analysis revealed a positive correlation of average interpulse period as well as mean signal amplitude with forewing length. These results suggest wing patterns, but less likely vibratory signals, to contain information about species identity. Furthermore, receivers may be able to estimate the body size of a signaler solely on the basis of substrate-borne sound. PMID:24818592

  5. Correlation of hierarchal Upper Silurian stacking patterns generated by Milankovitch orbital forcing

    SciTech Connect

    Mauriello, D.J.; Ketterer, M.W. . Dept. of Geology)

    1993-03-01

    The Upper Silurian Wills Creek Formation in Pennsylvania and Maryland is entirely divisible into meter-scale allocycles. Stacking patterns of these allocycles reveal a hierarchy consistent with predictions based on the Milankovitch model of orbital forcing. Asymmetrical Sixth-Order cycles (PACs), bounded by surfaces produced by precessional sea-level rises, are divisible into a lower highstand portion and an upper lowstand portion separated by a sharp sea-level fall surface produced by a rapid sea-level drop within the precessional cycle. Sixth-Order cycles may be genetically grouped into Fifth-Order (100 ky.) and subsequently, Fourth-Order (400 ky.) cycles, each of which exhibits a distinct internal symmetry. Fifth-Order cycles, on average three to four meters in thickness, are composed of a basal transgressive portion consisting of two PACs followed by two or three successively regressive PACs. Four Fifth-Order cycles constitute a complete Fourth-Order cycle, in which the second Fifth-Order cycle contains facies representing the deepest or least restricted paleoenvironments. In each case, the fundamental Sixth-Order cycles were generated by the precessional signal modulated by orbital eccentricity variations. Over distances in excess of 100 km, Wills Creek facies change laterally from nearshore marine to fluvial coastal plain. Stacking patterns in these distinct facies are identical, and thus correlative, indicating the basin-wide extent of the stratigraphic events which produced these patterns. These correlations demonstrate that Milankovitch-driven eustatic sea-level fluctuations were occurring during the Late Silurian.

  6. Diversity of wing patterns and abdomen-generated substrate sounds in 3 European scorpionfly species

    PubMed Central

    Hartbauer, Manfred; Gepp, Johannes; Hinteregger, Karin; Koblmüller, Stephan

    2016-01-01

    In the genus Panorpa (Insecta: Mecoptera), also known as scorpionflies, premating behavior includes repeated sequences of slow wing movements (waving, fanning, flagging) which are accompanied by rapid abdomen vibrations that generate substantial substrate-borne sound. It is still unknown whether wing patterns or vibratory signals contain information about species identity, sex and/or the quality of potential mating partners. Besides species-specific pheromones, these multimodal signals may be of particular importance for the maintenance of reproductive isolation in sympatrically occurring scorpionfly species. Here, we analyzed phyologenetic relationships among, and the pattern of forewings as well as substrate-borne sound in 3 different sympatric Central-European scorpionfly species (P. communis, P. germanica, and P. alpina). Divergence time estimates, based on 879 bp of the mitochondrial COI gene, indicate longstanding separate evolutionary histories for the studied Panorpa species. Morphological analysis revealed that wing length as an indicator of body size increased in the following order: P. alpina < P. germanica < P. communis. Individuals can be assigned to the correct species and sex with high accuracy just by evaluation of the number of dark spots and the proportion of wing pigmentation. Despite high variability of interpulse period at an individual level, across species analysis revealed a positive correlation of average interpulse period as well as mean signal amplitude with forewing length. These results suggest wing patterns, but less likely vibratory signals, to contain information about species identity. Furthermore, receivers may be able to estimate the body size of a signaler solely on the basis of substrate-borne sound. PMID:24818592

  7. A Modeling Approach on Why Simple Central Pattern Generators Are Built of Irregular Neurons

    PubMed Central

    Reyes, Marcelo Bussotti; Carelli, Pedro Valadão; Sartorelli, José Carlos; Pinto, Reynaldo Daniel

    2015-01-01

    The crustacean pyloric Central Pattern Generator (CPG) is a nervous circuit that endogenously provides periodic motor patterns. Even after about 40 years of intensive studies, the rhythm genesis is still not rigorously understood in this CPG, mainly because it is made of neurons with irregular intrinsic activity. Using mathematical models we addressed the question of using a network of irregularly behaving elements to generate periodic oscillations, and we show some advantages of using non-periodic neurons with intrinsic behavior in the transition from bursting to tonic spiking (as found in biological pyloric CPGs) as building components. We studied two- and three-neuron model CPGs built either with Hindmarsh-Rose or with conductance-based Hodgkin-Huxley-like model neurons. By changing a model’s parameter we could span the neuron’s intrinsic dynamical behavior from slow periodic bursting to fast tonic spiking, passing through a transition where irregular bursting was observed. Two-neuron CPG, half center oscillator (HCO), was obtained for each intrinsic behavior of the neurons by coupling them with mutual symmetric synaptic inhibition. Most of these HCOs presented regular antiphasic bursting activity and the changes of the bursting frequencies was studied as a function of the inhibitory synaptic strength. Among all HCOs, those made of intrinsic irregular neurons presented a wider burst frequency range while keeping a reliable regular oscillatory (bursting) behavior. HCOs of periodic neurons tended to be either hard to change their behavior with synaptic strength variations (slow periodic burster neurons) or unable to perform a physiologically meaningful rhythm (fast tonic spiking neurons). Moreover, 3-neuron CPGs with connectivity and output similar to those of the pyloric CPG presented the same results. PMID:25799556

  8. Biological oscillations for learning walking coordination: dynamic recurrent neural network functionally models physiological central pattern generator

    PubMed Central

    Hoellinger, Thomas; Petieau, Mathieu; Duvinage, Matthieu; Castermans, Thierry; Seetharaman, Karthik; Cebolla, Ana-Maria; Bengoetxea, Ana; Ivanenko, Yuri; Dan, Bernard; Cheron, Guy

    2013-01-01

    The existence of dedicated neuronal modules such as those organized in the cerebral cortex, thalamus, basal ganglia, cerebellum, or spinal cord raises the question of how these functional modules are coordinated for appropriate motor behavior. Study of human locomotion offers an interesting field for addressing this central question. The coordination of the elevation of the 3 leg segments under a planar covariation rule (Borghese et al., 1996) was recently modeled (Barliya et al., 2009) by phase-adjusted simple oscillators shedding new light on the understanding of the central pattern generator (CPG) processing relevant oscillation signals. We describe the use of a dynamic recurrent neural network (DRNN) mimicking the natural oscillatory behavior of human locomotion for reproducing the planar covariation rule in both legs at different walking speeds. Neural network learning was based on sinusoid signals integrating frequency and amplitude features of the first three harmonics of the sagittal elevation angles of the thigh, shank, and foot of each lower limb. We verified the biological plausibility of the neural networks. Best results were obtained with oscillations extracted from the first three harmonics in comparison to oscillations outside the harmonic frequency peaks. Physiological replication steadily increased with the number of neuronal units from 1 to 80, where similarity index reached 0.99. Analysis of synaptic weighting showed that the proportion of inhibitory connections consistently increased with the number of neuronal units in the DRNN. This emerging property in the artificial neural networks resonates with recent advances in neurophysiology of inhibitory neurons that are involved in central nervous system oscillatory activities. The main message of this study is that this type of DRNN may offer a useful model of physiological central pattern generator for gaining insights in basic research and developing clinical applications. PMID:23755009

  9. Homologues of serotonergic central pattern generator neurons in related nudibranch molluscs with divergent behaviors.

    PubMed

    Newcomb, James M; Katz, Paul S

    2007-04-01

    Homologues of a neuron that contributes to a species-specific behavior were identified and characterized in species lacking that behavior. The nudibranch Tritonia diomedea swims by flexing its body dorsally and ventrally. The dorsal swim interneurons (DSIs) are components of the central pattern generator (CPG) underlying this rhythmic motor pattern and also activate crawling. Homologues of the DSIs were identified in six nudibranchs that do not exhibit dorsal-ventral swimming: Tochuina tetraquetra, Melibe leonina, Dendronotus iris, D. frondosus, Armina californica, and Triopha catalinae. Homology was based upon shared features that distinguish the DSIs from all other neurons: (1) serotonin immunoreactivity, (2) location in the Cerebral serotonergic posterior (CeSP) cluster, and (3) axon projection to the contralateral pedal ganglion. The DSI homologues, named CeSP-A neurons, share additional features with the DSIs: irregular basal firing, synchronous inputs, electrical coupling, and reciprocal inhibition. Unlike the DSIs, the CeSP-A neurons were not rhythmically active in response to nerve stimulation. The CeSP-A neurons in Tochuina and Triopha also excited homologues of the Tritonia Pd5 neuron, a crawling efferent. Thus, the CeSP-A neurons and the DSIs may be part of a conserved network related to crawling that may have been co-opted into a rhythmic swim CPG in Tritonia. PMID:17180703

  10. Directed functional connectivity matures with motor learning in a cortical pattern generator

    PubMed Central

    Day, Nancy F.; Terleski, Kyle L.; Nykamp, Duane Q.

    2013-01-01

    Sequential motor skills may be encoded by feedforward networks that consist of groups of neurons that fire in sequence (Abeles 1991; Long et al. 2010). However, there has been no evidence of an anatomic map of activation sequence in motor control circuits, which would be potentially detectable as directed functional connectivity of coactive neuron groups. The proposed pattern generator for birdsong, the HVC (Long and Fee 2008; Vu et al. 1994), contains axons that are preferentially oriented in the rostrocaudal axis (Nottebohm et al. 1982; Stauffer et al. 2012). We used four-tetrode recordings to assess the activity of ensembles of single neurons along the rostrocaudal HVC axis in anesthetized zebra finches. We found an axial, polarized neural network in which sequential activity is directionally organized along the rostrocaudal axis in adult males, who produce a stereotyped song. Principal neurons fired in rostrocaudal order and with interneurons that were rostral to them, suggesting that groups of excitatory neurons fire at the leading edge of travelling waves of inhibition. Consistent with the synchronization of neurons by caudally travelling waves of inhibition, the activity of interneurons was more coherent in the orthogonal mediolateral axis than in the rostrocaudal axis. If directed functional connectivity within the HVC is important for stereotyped, learned song, then it may be lacking in juveniles, which sing a highly variable song. Indeed, we found little evidence for network directionality in juveniles. These data indicate that a functionally directed network within the HVC matures during sensorimotor learning and may underlie vocal patterning. PMID:23175804

  11. Lidocaine excites both pre- and postsynaptic neurons of reconstructed respiratory pattern generator in Lymnaea stagnalis.

    PubMed

    Onizuka, Shin; Kasaba, Toshiharu; Hamakawa, Toshiro; Takasaki, Mayumi

    2005-01-01

    Lidocaine causes both inhibition and excitation in the central nervous system, including the respiratory pattern. The excitation induced by an excessive dose of local anesthetic is thought to be the result of an initial blockade of an inhibitory pathway in the cerebral cortex. To clarify the effect of lidocaine on the pre- and postsynaptic neurons of an inhibitory synapse, a cultured soma-soma respiratory pattern generator model consisting of two neurons from the snail Lymnaea stagnalis were reconstructed in vitro. First we investigated the effects of lidocaine on single presynaptic (RPeD1) or postsynaptic (VD4) neurons. While RPeD1 and VD4 were simultaneously recorded, the number of action potentials, the membrane potential, and the wavelength of the action potential were compared before and after lidocaine (0.01, 0.1, and 1 mM) administration. Lidocaine increased the number of action potentials and the wavelength of a single action potential, and it depolarized the resting membrane potential in both RPeD1 and VD4 neurons in a dose-dependent manner. Furthermore, lidocaine decreased outward potassium currents. In soma-soma pairs, RPeD1 excitation and VD4 suppression occurred in 0.01 mM lidocaine, whereas both RPeD1 and VD4 neurons were excited by 0.1 and 1 mM lidocaine. In conclusion, lidocaine causes a reduction in synaptic transmission and general neuronal excitation in both presynaptic and postsynaptic neurons. PMID:15616074

  12. Deep sequencing-generated modules demonstrate coherent expression patterns for various cardiac diseases.

    PubMed

    Hong, Seong-Eui; Nho, Kyoung Jin; Song, Hong Ki; Kim, Do Han

    2015-12-10

    As sequencing technology rapidly develops, gene annotations have also become increasingly sophisticated with incorporation of information regarding the temporal-spatial context of alternative splicing patterns, developmental stages, and tissue specificity. The present study aimed to identify the heart-enriched genes based on next-generation sequencing data and to investigate the gene modules demonstrating coherent expression patterns for various cardiac disease-related perturbations. Seven gene modules, including 382 heart-enriched genes, were identified. At least two modules containing differentially expressed genes were experimentally confirmed to be highly sensitive to various cardiac diseases. Transcription factors regulating the gene modules were then analyzed based on knowledgebase information; the expression of eight transcription factors changed significantly during pressure-overload cardiac hypertrophy, suggesting possible regulation of the modules by the identified transcription factors. Collectively, our results contribute to the classification of heart-enriched genes and their modules and would aid in identification of the transcription factors involved in cardiac pathogenesis in the future. PMID:26232333

  13. A Method for Generating Natural and User-Defined Sniffing Patterns in Anesthetized or Reduced Preparations

    PubMed Central

    Carey, Ryan M.; Wachowiak, Matt

    2009-01-01

    Sniffing has long been thought to play a critical role in shaping neural responses to odorants at multiple levels of the nervous system. However, it has been difficult to systematically examine how particular parameters of sniffing behavior shape odorant-evoked activity, in large part because of the complexity of sniffing behavior and the difficulty in reproducing this behavior in an anesthetized or reduced preparation. Here we present a method for generating naturalistic sniffing patterns in such preparations. The method involves a nasal ventilator whose movement is controlled by an analog command voltage. The command signal may consist of intranasal pressure transients recorded from awake rats and mice or user-defined waveforms. This “sniff playback” device generates intranasal pressure and airflow transients in anesthetized animals that approximate those recorded from the awake animal and are reproducible across trials and across preparations. The device accurately reproduces command waveforms over an amplitude range of approximately 1 log unit and up to frequencies of approximately 12 Hz. Further, odorant-evoked neural activity imaged during sniff playback appears similar to that seen in awake animals. This method should prove useful in investigating how the parameters of odorant sampling shape neural responses in a variety of experimental settings. PMID:18791186

  14. Rostral versus caudal differences in mechanical entrainment of the lamprey central pattern generator for locomotion.

    PubMed

    Tytell, Eric D; Cohen, Avis H

    2008-05-01

    In fishes, undulatory swimming is produced by sets of spinal interneurons constituting a central pattern generator (CPG). The CPG generates waves of muscle activity that travel from head to tail, which then bend the body into wave shapes that also travel from head to tail. In many fishes, the wavelengths of the neural and mechanical waves are different, resulting in a rostral-to-caudal gradient in phase lag between muscle activity and bending. The neural basis of this phase gradient was investigated in the lamprey spinal cord using an isolated in vitro preparation. Fictive swimming was induced using d-glutamate and the output of the CPG was measured using suction electrodes placed on the ventral roots. The spinal cord was bent sinusoidally at various points along its length. First, the ranges of entrainment were estimated. Middle segments were able to entrain to frequencies approximately twice as high as those at end segments. Next, phase lags between centers of ventral root bursts and the stimulus were determined. Two halves of the cycle were identified: stretching and shortening of the edge of spinal cord on the same side as the electrode. Stimuli at rostral segments tended to entrain segmental bursting at the beginning of the stretch phase, almost 50% out of phase with previously measured in vivo electromyography data. Stimuli at caudal segments, in contrast, entrained segments at the end of stretch and the beginning of shortening, approximately the same phase as in vivo data. PMID:18256165

  15. Hardware architecture for rapid generation of electro-holographic fringe patterns

    NASA Astrophysics Data System (ADS)

    Watlington, John A.; Lucente, Mark E.; Sparrell, Carlton J.; Bove, V. Michael, Jr.; Tamitani, Ichiro

    1995-04-01

    This report describe the hardware architecture and software implementation of a hologram computing system developed at the MIT Media Laboratory. The hologram computing employs specialized stream-processing hardware embedded in the Cheops Image Processing system--a compact, block data-flow parallel processor. A superposition stream processor performs weighted summations of arbitrary 1D basis functions. A two-step holographic computation method--called Hogel-Vector encoding--utilizes the stream processor's computational power. An array of encoded hogel vectors, generated from a 3D scene description, is rapidly decoded using the processor. The resulting 36-megabyte holographic pattern is transferred to frame- buffers and then fed to a real-time electro-holographic display, producing 3D holographic images. System performance is sufficient to generate an image volume approximately 100 mm per side in 3 seconds. The architecture is scalable over a limited range in both display size and computational power. The limitations on system scalability will be identified and solutions proposed.

  16. The Hyper-X Antenna Radiation Pattern Tests and Radio Frequency System Redesign

    NASA Technical Reports Server (NTRS)

    Hodge, Mark W.; Kelley, John W.

    2006-01-01

    Testing was performed to determine the antenna radiation pattern measurements of the Hyper-X, X-43 ship 2 aircraft. One test was conducted at the Air Force Flight Test Center (AFFTC) Benefield Anechoic Facility (BAF) on January 24-January 27, 2000. A second test was done at MicroCraft in Tullahoma Tennessee by the Naval Air Weapons Center (NAWC) China Lake, California on September 8, 2001. The overall test objective was to gather qualitative antenna radiation pattern data from installed antennas on the HXRV. This objective was accomplished by collecting antenna radiation patterns at selected elevations of the HXRV. The test data was used to identify areas of RF coverage and assist in positioning the P-3 aircraft for best RF reception. The antenna pattern data presented nulls and possible low RF reception areas around the aircraft. This led to a redesign of the RF system. The redesigned system provided redundancy in case a telemetry transmitter should fail. The redesign provided more complete RF coverage within the antenna's capabilities. A second look at the flight path and necessary data collection led to a change in the beacon transponder system.

  17. Retrieval Mode Distinguishes the Testing Effect from the Generation Effect

    ERIC Educational Resources Information Center

    Karpicke, Jeffrey D.; Zaromb, Franklin M.

    2010-01-01

    A series of four experiments examined the effects of generation vs. retrieval practice on subsequent retention. Subjects were first exposed to a list of target words. Then the subjects were shown the targets again intact for Read trials or they were shown fragments of the targets. Subjects in Generate conditions were told to complete the fragments…

  18. Feedback control of variability in the cycle period of a central pattern generator.

    PubMed

    Hooper, Ryan M; Tikidji-Hamburyan, Ruben A; Canavier, Carmen C; Prinz, Astrid A

    2015-11-01

    We address how feedback to a bursting biological pacemaker with intrinsic variability in cycle length can affect that variability. Specifically, we examine a hybrid circuit constructed of an isolated crab anterior burster (AB)/pyloric dilator (PD) pyloric pacemaker receiving virtual feedback via dynamic clamp. This virtual feedback generates artificial synaptic input to PD with timing determined by adjustable phase response dynamics that mimic average burst intervals generated by the lateral pyloric neuron (LP) in the intact pyloric network. Using this system, we measure network period variability dependence on the feedback element's phase response dynamics and find that a constant response interval confers minimum variability. We further find that these optimal dynamics are characteristic of the biological pyloric network. Building upon our previous theoretical work mapping the firing intervals in one cycle onto the firing intervals in the next cycle, we create a theoretical map of the distribution of all firing intervals in one cycle to the distribution of firing intervals in the next cycle. We then obtain an integral equation for a stationary self-consistent distribution of the network periods of the hybrid circuit, which can be solved numerically given the uncoupled pacemaker's distribution of intrinsic periods, the nature of the network's feedback, and the phase resetting characteristics of the pacemaker. The stationary distributions obtained in this manner are strongly predictive of the experimentally observed distributions of hybrid network period. This theoretical framework can provide insight into optimal feedback schemes for minimizing variability to increase reliability or maximizing variability to increase flexibility in central pattern generators driven by pacemakers with feedback. PMID:26334008

  19. Field test of two high-pressure direct-contact downhole steam generators. Volume II. Oxygen/diesel system

    SciTech Connect

    Moreno, J.B.

    1983-07-01

    A field test of an oxygen/diesel fuel, direct contact steam generator has been completed. The field test, which was a part of Project DEEP STEAM and was sponsored by the US Department of Energy, involved the thermal stimulation of a well pattern in the Tar Zone of the Wilmington Oil Field. The activity was carried out in cooperation with the City of Long Beach and the Long Beach Oil Development Company. The steam generator was operated at ground level, with the steam and combustion products delivered to the reservoir through 2022 feet of calcium-silicate insulated tubing. The objectives of the test included demonstrations of safety, operational ease, reliability and lifetime; investigations of reservoir response, environmental impact, and economics; and comparison of those points with a second generator that used air rather than oxygen. The test was extensively instrumented to provide the required data. Excluding interruptions not attributable to the oxygen/diesel system, steam was injected 78% of the time. System lifetime was limited by the combustor, which required some parts replacement every 2 to 3 weeks. For the conditions of this particular test, the use of trucked-in LOX resulted in liess expense than did the production of the equivalent amount of high pressure air using on site compressors. No statistically significant production change in the eight-acre oxygen system well pattern occurred during the test, nor were any adverse effects on the reservoir character detected. Gas analyses during the field test showed very low levels of SOX (less than or equal to 1 ppM) in the generator gaseous effluent. The SOX and NOX data did not permit any conclusion to be drawn regarding reservoir scrubbing. Appreciable levels of CO (less than or equal to 5%) were measured at the generator, and in this case produced-gas analyses showed evidence of significant gas scrubbing. 64 figures, 10 tables.

  20. Rice HYDROPEROXIDE LYASES with unique expression patterns generate distinct aldehyde signatures in Arabidopsis.

    PubMed

    Chehab, E W; Raman, G; Walley, J W; Perea, J V; Banu, G; Theg, S; Dehesh, K

    2006-05-01

    HYDROPEROXIDE LYASE (HPL) genes encode enzymes that catalyze the cleavage of fatty acid hydroperoxides into aldehydes and oxoacids. There are three HPLs in rice (Oryza sativa), designated OsHPL1 through OsHPL3. To explore the possibility of differential functional activities among these genes, we have examined their expression patterns and biochemical properties of their encoded products. Transcript analysis indicates that these genes have distinct patterns and levels of expression. OsHPL1 is ubiquitously expressed, OsHPL2 is expressed in the leaves and leaf sheaths, whereas OsHPL3 is wound inducible and expressed exclusively in leaves. OsHPLs also differ in their substrate preference as determined by in vitro enzyme assays using 9-/13-hydroperoxy linolenic and 9-/13-hydroperoxy linoleic acids as substrates. OsHPL1 and OsHPL2 metabolize 9-/13-hydroperoxides, whereas OsHPL3 metabolizes 13-hydroperoxy linolenic acid exclusively. Sequence alignments of the HPL enzymes have identified signature residues potentially responsible for the substrate specificity/preference of these enzymes. All three OsHPLs are chloroplast localized as determined by chloroplast import assays and green fluorescent protein (GFP) fusion studies. Aldehyde measurements in transgenic Arabidopsis (Arabidopsis thaliana) plants overexpressing individual OsHPL-GFP fusions indicate that all rice HPLs are functional in a heterologous system, and each of them generates a distinct signature of the metabolites. Interestingly, these aldehydes were only detectable in leaves, but not in roots, despite similar levels of OsHPL-GFP proteins in both tissues. Similarly, there were undetectable levels of aldehydes in rice roots, in spite of the presence of OsHPL1 transcripts. Together, these data suggest that additional tissue-specific mechanism(s) beyond transcript and HPL enzyme abundance, regulate the levels of HPL-derived metabolites. PMID:16531481

  1. Improved zonal wavefront reconstruction algorithm for Hartmann type test with arbitrary grid patterns

    NASA Astrophysics Data System (ADS)

    Li, Mengyang; Li, Dahai; Zhang, Chen; E, Kewei; Hong, Zhihan; Li, Chengxu

    2015-08-01

    Zonal wavefront reconstruction by use of the well known Southwell algorithm with rectangular grid patterns has been considered in the literature. However, when the grid patterns are nonrectangular, modal wavefront reconstruction has been extensively used. We propose an improved zonal wavefront reconstruction algorithm for Hartmann type test with arbitrary grid patterns. We develop the mathematical expressions to show that the wavefront over arbitrary grid patterns, such as misaligned, partly obscured, and non-square mesh grids, can be estimated well. Both iterative solution and least-square solution for the proposed algorithm are described and compared. Numerical calculation shows that the zonal wavefront reconstruction over nonrectangular profile with the proposed algorithm results in a significant improvement in comparison with the Southwell algorithm.

  2. Concept and analytical basis for revistas - A fast, flexible computer/graphic system for generating periodic satellite coverage patterns

    NASA Technical Reports Server (NTRS)

    King, J. C.

    1976-01-01

    The generation of satellite coverage patterns is facilitated by three basic strategies: use of a simplified physical model, permitting rapid closed-form calculation; separation of earth rotation and nodal precession from initial geometric analyses; and use of symmetries to construct traces of indefinite length by repetitive transposition of basic one-quadrant elements. The complete coverage patterns generated consist of a basic nadir trace plus a number of associated off-nadir traces, one for each sensor swath edge to be delineated. Each trace is generated by transposing one or two of the basic quadrant elements into a circle on a nonrotating earth model sphere, after which the circle is expanded into the actual 'helical' pattern by adding rotational displacements to the longitude coordinates. The procedure adapts to the important periodic coverage cases by direct insertion of the characteristic integers N and R (days and orbital revolutions, respectively, per coverage period).

  3. Testing key predictions of the associative account of mirror neurons in humans using multivariate pattern analysis.

    PubMed

    Oosterhof, Nikolaas N; Wiggett, Alison J; Cross, Emily S

    2014-04-01

    Cook et al. overstate the evidence supporting their associative account of mirror neurons in humans: most studies do not address a key property, action-specificity that generalizes across the visual and motor domains. Multivariate pattern analysis (MVPA) of neuroimaging data can address this concern, and we illustrate how MVPA can be used to test key predictions of their account. PMID:24775171

  4. Brief Report: Eye-Movement Patterns during an Embedded Figures Test in Children with ASD

    ERIC Educational Resources Information Center

    Keehn, Brandon; Brenner, Laurie A.; Ramos, Aurora I.; Lincoln, Alan J.; Marshall, Sandra P.; Muller, Ralph-Axel

    2009-01-01

    The present study examined fixation frequency and duration during an Embedded Figures Test (EFT) in an effort to better understand the attentional and perceptual processes by which individuals with autism spectrum disorder (ASD) achieve accelerated EFT performance. In particular, we aimed to elucidate differences in the patterns of eye-movement in…

  5. MULTICORR: A Computer Program for Fast, Accurate, Small-Sample Testing of Correlational Pattern Hypotheses.

    ERIC Educational Resources Information Center

    Steiger, James H.

    1979-01-01

    The program presented computes a chi-square statistic for testing pattern hypotheses on correlation matrices. The statistic is based on a multivariate generalization of the Fisher r-to-z transformation. This statistic has small sample performance which is superior to an analogous likelihood ratio statistic obtained via the analysis of covariance…

  6. GENETIC ACTIVITY PROFILES AND PATTERN RECOGNITION IN TEST BATTERY SELECTION (JOURNAL VERSION)

    EPA Science Inventory

    Computer-generated genetic activity profiles and pairwise matching procedures may aid in the selection of the most appropriate short-term bioassays to be used in test batteries for the evaluation of the genotoxicity of a given chemical or group of chemicals. Selection of test bat...

  7. The next generation of microbiological testing of poultry.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microbiological testing of food products is a common practice of food processors to ensure compliance with food safety criteria. Sampling on its own is of limited value, but when applied regularly at different stages of the food chain, microbiology testing can be an integral part of a quality contr...

  8. Improving Large Enrollment Undergraduate Instruction With Computer Generated, Repeatable Tests.

    ERIC Educational Resources Information Center

    Hammer, Mark; Henderson, C. Obert

    In addition to the usual drawbacks of large enrollment college classes such as impersonal atmosphere, discouragement of questions, and insensitivity to individual differences, the testing methods that tend to be associated with large classes can be detrimental to the learning process. Objective tests decrease the level of intellectual mastery…

  9. Sensory feedback mechanism underlying entrainment of central pattern generator to mechanical resonance.

    PubMed

    Iwasaki, T; Zheng, M

    2006-04-01

    Rhythmic body motions observed in animal locomotion are known to be controlled by neuronal circuits called central pattern generators (CPGs). It appears that CPGs are energy efficient controllers that cooperate with biomechanical and environmental constraints through sensory feedback. In particular, the CPGs tend to induce rhythmic motion of the body at a natural frequency, i.e., the CPGs are entrained to a mechanical resonance by sensory feedback. The objective of this paper is to uncover the mechanism of entrainment resulting from the dynamic interaction of the CPG and mechanical system. We first develop multiple CPG models for the reciprocal inhibition oscillator (RIO) and examine through numerical experiments whether they can be entrained to a simple pendulum. This comparative study identifies the neuronal properties essential for the entrainment. We then analyze the simplest model that captures the essential dynamics via the method of harmonic balance. It is shown that robust entrainment results from a strong, positive-feedback coupling of a lightly damped mechanical system and the RIO consisting of neurons with the complete adaptation property. PMID:16404611

  10. Coupling relationship between the central pattern generator and the cerebral cortex with time delay.

    PubMed

    Lu, Qiang

    2015-08-01

    Brain activity is a cooperative process among neurons and involves the coupling relationship, which is crucial to perform operational tasks in various specialized areas of the nervous system. A finite signal transmission speed along the axons results in a space-dependent time delay. The central pattern generator (CPG) can in principle produce basic locomotor rhythm in the absence of inputs from higher brain centers and peripheral sensory feedback. To study the dynamic performance of CPG with time delay and its coupling relationship with the cerebral cortex, a new CPG model with time delay and a model of the neural mass model (NMM) and the CPG are developed. The coupling model is based on biological experimental results. Bifurcation theories and maximal Lyapunov exponent are used to analyze the dynamic performance. From the results, some CPGs are suggested to be embedded in limbs and composed of the parameters space which corresponds to the one of the cerebral cortex. This embodiment of humans can reduce the burden of the brain and simplify the control of the locomotion. The results also show that the phase diagram of the CPG cannot keep the limit cycle, and that the state of the NMM becomes increasingly chaotic as time delay increases. This finding implies that a person with slow reaction can easily lose the stability of his or her locomotion. PMID:26157515

  11. Multiple mechanisms for integrating proprioceptive inputs that converge on the same motor pattern-generating network.

    PubMed

    Barrière, Gregory; Simmers, John; Combes, Denis

    2008-08-27

    Movement-derived sensory feedback adapts centrally generated motor programs to changing behavioral demands. Motor circuit output may also be shaped by distinct proprioceptive systems with different central actions, although little is known about the integrative processes by which such convergent sensorimotor regulation occurs. Here, we explore the combined actions of two previously identified proprioceptors on the gastric mill motor network in the lobster stomatogastric nervous system. Both mechanoreceptors [anterior gastric receptor (AGR) and posterior stomach receptor (PSR)] access the gastric circuit via the same pair of identified projection interneurons that either excite [commissural gastric (CG)] or inhibit [gastric inhibitor (GI)] different subsets of gastric network neurons. Mechanosensory information from the two receptors is integrated upstream to the gastric circuit at two levels: (1) postsynaptically, where both receptors excite the GI neuron while exerting opposing effects on the CG neuron, and (2) presynaptically, where PSR reduces AGR's excitation of the CG projection neuron. Concomitantly PSR selectively enhances AGR's activation of the GI neuron, possibly also via a presynaptic action. PSR's influences also far outlast its transient synaptic effects, indicating the additional involvement of modulatory processes. Consequently, PSR activation causes parallel input from AGR to be conveyed preferentially via the GI interneuron, resulting in a prolonged switch in the pattern of gastric circuit output. Therefore, via a combination of short- and long-lasting, presynaptic and postsynaptic actions, one proprioceptive system is able to promote its impact on a target motor network by biasing the access of a different sensory system to the same circuit. PMID:18753383

  12. Generation and regulation of multiple focuses by tight focusing of patterned vector optical field array

    NASA Astrophysics Data System (ADS)

    Tu, Chenghou; Cai, Mengqiang; Zhang, Huihui; Qian, Shengxia; Li, Yongnan; Wang, Hui-Tian; Optical Field Regulation Team

    2014-03-01

    We have numerically studied the tight focusing of patterned vector optical field array based on the modified Richard-Wolf diffracting integration. By tailoring the spatial arrangement and the polarization distribution of the individual vector optical field, sub-wavelength multiple focal spots with different arrangement can be easily realized. The size of the focal spots, the distance between different focal spots and the arrangement of focal spots can all be regulated by varying the parameters of VOFs. Focal spots with the arrangement of hexagon, rectangle or rhombus can be obtained depending on the different setting conditions of PVOF. To check the numerical results, we experimentally generated the PVOFs according to the numerical conditions, and utilize the tightly focused optical fields to ablate the single crystal silicon wafer surface. Based on SEM images of the ablated sample surface, we find that the experiment results, which indirectly measured the intensity distribution and the size of the focal spots, agree with the numerical results very well. The tight focusing of PVOF opens a new window for regulating the focal intensity distribution due to the control diversity. As a result, it can be very flexible and helpful in many applications, such as micro-nano parallel fabrication and optical manipulation, etc.

  13. The contribution of a central pattern generator in a reflex-based neuromuscular model

    PubMed Central

    Dzeladini, Florin; van den Kieboom, Jesse; Ijspeert, Auke

    2014-01-01

    Although the concept of central pattern generators (CPGs) controlling locomotion in vertebrates is widely accepted, the presence of specialized CPGs in human locomotion is still a matter of debate. An interesting numerical model developed in the 90s’ demonstrated the important role CPGs could play in human locomotion, both in terms of stability against perturbations, and in terms of speed control. Recently, a reflex-based neuro-musculo-skeletal model has been proposed, showing a level of stability to perturbations similar to the previous model, without any CPG components. Although exhibiting striking similarities with human gaits, the lack of CPG makes the control of speed/step length in the model difficult. In this paper, we hypothesize that a CPG component will offer a meaningful way of controlling the locomotion speed. After introducing the CPG component in the reflex model, and taking advantage of the resulting properties, a simple model for gait modulation is presented. The results highlight the advantages of a CPG as feedforward component in terms of gait modulation. PMID:25018712

  14. DESIGN, FABRICATION, AND TESTING OF AN ADVANCED, NON-POLLUTING TURBINE DRIVE GAS GENERATOR

    SciTech Connect

    Unknown

    2002-03-31

    The objectives of this report period were to complete the development of the Gas Generator design, which was done; fabricate and test of the non-polluting unique power turbine drive gas Gas Generator, which has been postponed. Focus during this report period has been to complete the brazing and bonding necessary to fabricate the Gas Generator hardware, continue making preparations for fabricating and testing the Gas Generator, and continuing the fabrication of the Gas Generator hardware and ancillary hardware in preparation for the test program. Fabrication is more than 95% complete and is expected to conclude in early May 2002. the test schedule was affected by relocation of the testing to another test supplier. The target test date for hot fire testing is now not earlier than June 15, 2002.

  15. Versatile pattern generation of periodic, high aspect ratio Si nanostructure arrays with sub-50-nm resolution on a wafer scale

    PubMed Central

    2013-01-01

    We report on a method of fabricating variable patterns of periodic, high aspect ratio silicon nanostructures with sub-50-nm resolution on a wafer scale. The approach marries step-and-repeat nanoimprint lithography (NIL) and metal-catalyzed electroless etching (MCEE), enabling near perfectly ordered Si nanostructure arrays of user-defined patterns to be controllably and rapidly generated on a wafer scale. Periodic features possessing circular, hexagonal, and rectangular cross-sections with lateral dimensions down to sub-50 nm, in hexagonal or square array configurations and high array packing densities up to 5.13 × 107 structures/mm2 not achievable by conventional UV photolithography are fabricated using this top-down approach. By suitably tuning the duration of catalytic etching, variable aspect ratio Si nanostructures can be formed. As the etched Si pattern depends largely on the NIL mould which is patterned by electron beam lithography (EBL), the technique can be used to form patterns not possible with self-assembly methods, nanosphere, and interference lithography for replication on a wafer scale. Good chemical resistance of the nanoimprinted mask and adhesion to the Si substrate facilitate good pattern transfer and preserve the smooth top surface morphology of the Si nanostructures as shown in TEM. This approach is suitable for generating Si nanostructures of controlled dimensions and patterns, with high aspect ratio on a wafer level suitable for semiconductor device production. PMID:24289275

  16. Test results for second-generation low thrust bipropellant engines

    NASA Astrophysics Data System (ADS)

    Schwende, M. A.; Schulte, G.

    1993-01-01

    An account is given of the development priorities, design features, and performance of second-generation, low-thrust (10 N) thrusters for satellite orbit and attitude correction maneuvers. Detailed information is presented for the qualification trials of a related, 4-N thruster. The bipropellant fuels used are MMH and MON-1.

  17. Initial benchmarking of a new electron-beam raster pattern generator for 130-100 nm maskmaking

    NASA Astrophysics Data System (ADS)

    Sauer, Charles A.; Abboud, Frank E.; Babin, Sergey V.; Chakarian, Varoujan; Ghanbari, Abe; Innes, Robert; Trost, David; Raymond, Frederick, III

    2000-07-01

    The decision by the Semiconductor Industry Association (SIA) to accelerate the continuing evolution to smaller linewidths is consistent with the commitment by Etec Systems, Inc. to rapidly develop new technologies for pattern generation systems with improved resolution, critical dimension (CD) uniformity, positional accuracy, and throughput. Current pattern generation designs are inadequate to meet the more advanced requirements for masks, particularly at or below the 100 nm node. Major changes to all pattern generation tools will be essential to meet future market requirements. An electron-beam (e-beam) system that is designed to meet the challenges for 130 - 100 nm device generation with extendibility to the 70-nm range will be discussed. This system has an architecture that includes a graybeam writing strategy, a new state system, and improved thermal management. Detailed changes include a pulse width modulated blanking system, per-pixel deflection, retrograde scanning multipass writing, and a column with a 50 kV accelerating voltage that supports a dose of up to 45 (mu) C/cm2 with minimal amounts of resist heating. This paper examines current issues, our approach to meeting International Technology Roadmap for Semiconductors (ITRS) requirements, and some preliminary results from a new pattern generator.

  18. Automatically generated acceptance test: A software reliability experiment

    NASA Technical Reports Server (NTRS)

    Protzel, Peter W.

    1988-01-01

    This study presents results of a software reliability experiment investigating the feasibility of a new error detection method. The method can be used as an acceptance test and is solely based on empirical data about the behavior of internal states of a program. The experimental design uses the existing environment of a multi-version experiment previously conducted at the NASA Langley Research Center, in which the launch interceptor problem is used as a model. This allows the controlled experimental investigation of versions with well-known single and multiple faults, and the availability of an oracle permits the determination of the error detection performance of the test. Fault interaction phenomena are observed that have an amplifying effect on the number of error occurrences. Preliminary results indicate that all faults examined so far are detected by the acceptance test. This shows promise for further investigations, and for the employment of this test method on other applications.

  19. NEXT GENERATION SEDIMENT TOXICITY TESTING VIA DNA MICROARRAYS - PHASE I

    EPA Science Inventory

    The current SBIR solicitation states that the EPA is seeking “better sampling, analysis, and monitoring technologies” to improve hazardous waste management.  Development of new methods for testing contaminated sediments is an area of particular concern because many industri...

  20. Computerized In Vitro Test for Chemical Toxicity Based on Tetrahymena Swimming Patterns

    NASA Technical Reports Server (NTRS)

    Noever, David A.; Matsos, Helen C.; Cronise, Raymond J.; Looger, Loren L.; Relwani, Rachna A.; Johnson, Jacqueline U.

    1994-01-01

    An apparatus and a method for rapidly determining chemical toxicity have been evaluated as an alternative to the rabbit eye initancy test (Draize). The toxicity monitor includes an automated scoring of how motile biological cells (Tetrahymena pyriformis) slow down or otherwise change their swimming patterns in a hostile chemical environment. The method, called the motility assay (MA), is tested for 30 s to determine the chemical toxicity in 20 aqueous samples containing trace organics and salts. With equal or better detection limits, results compare favorably to in vivo animal tests of eye irritancy.

  1. Using aberration test patterns to optimize the performance of EUV aerial imaging microscopes

    SciTech Connect

    Mochi, Iacopo; Goldberg, Kenneth A.; Miyakawa, Ryan; Naulleau, Patrick; Han, Hak-Seung; Huh, Sungmin

    2009-06-16

    The SEMATECH Berkeley Actinic Inspection Tool (AIT) is a prototype EUV-wavelength zoneplate microscope that provides high quality aerial image measurements of EUV reticles. To simplify and improve the alignment procedure we have created and tested arrays of aberration-sensitive patterns on EUV reticles and we have compared their images collected with the AIT to the expected shapes obtained by simulating the theoretical wavefront of the system. We obtained a consistent measure of coma and astigmatism in the center of the field of view using two different patterns, revealing a misalignment condition in the optics.

  2. Decomposing risk: landscape structure and wolf behavior generate different predation patterns in two sympatric ungulates.

    PubMed

    Gervasi, Vincenzo; Sand, Hakan; Zimmermann, Barbara; Mattisson, Jenny; Wabakken, Petter; Linnell, John D C

    2013-10-01

    Recolonizing carnivores can have a large impact on the status of wild ungulates, which have often modified their behavior in the absence of predation. Therefore, understanding the dynamics of reestablished predator-prey systems is crucial to predict their potential ecosystem effects. We decomposed the spatial structure of predation by recolonizing wolves (Canis lupus) on two sympatric ungulates, moose (Alces alces) and roe deer (Capreolus capreolus), in Scandinavia during a 10-year study. We monitored 18 wolves with GPS collars, distributed over 12 territories, and collected records from predation events. By using conditional logistic regression, we assessed the contributions of three main factors, the utilization patterns of each wolf territory, the spatial distribution of both prey species, and fine-scale landscape structure, in determining the spatial structure of moose and roe deer predation risk. The reestablished predator-prey system showed a remarkable spatial variation in kill occurrence at the intra-territorial level, with kill probabilities varying by several orders of magnitude inside the same territory. Variation in predation risk was evident also when a spatially homogeneous probability for a wolf to encounter a prey was simulated. Even inside the same territory, with the same landscape structure, and when exposed to predation by the same wolves, the two prey species experienced an opposite spatial distribution of predation risk. In particular, increased predation risk for moose was associated with open areas, especially clearcuts and young forest stands, whereas risk was lowered for roe deer in the same habitat types. Thus, fine-scale landscape structure can generate contrasting predation risk patterns in sympatric ungulates, so that they can experience large differences in the spatial distribution of risk and refuge areas when exposed to predation by a recolonizing predator. Territories with an earlier recolonization were not associated with a lower hunting success for wolves. Such constant efficiency in wolf predation during the recolonization process is in line with previous findings about the naive nature of Scandinavian moose to wolf predation. This, together with the human-dominated nature of the Scandinavian ecosystem, seems to limit the possibility for wolves to have large ecosystem effects and to establish a behaviorally mediated trophic cascade in Scandinavia. PMID:24261051

  3. Chronic Malaria Revealed by a New Fluorescence Pattern on the Antinuclear Autoantibodies Test

    PubMed Central

    Hommel, Benjamin; Charuel, Jean-Luc; Jaureguiberry, Stéphane; Arnaud, Laurent; Courtin, Regis; Kassab, Petra; Prendki, Virginie; Paris, Luc; Ghillani-Dalbin, Pascale; Thellier, Marc; Caumes, Eric; Amoura, Zahir; Mazier, Dominique; Musset, Lucile; Buffet, Pierre; Miyara, Makoto

    2014-01-01

    Background Several clinical forms of malaria such as chronic carriage, gestational malaria or hyper-reactive malarial splenomegaly may follow a cryptic evolution with afebrile chronic fatigue sometimes accompanied by anemia and/or splenomegaly. Conventional parasitological tests are often negative or not performed, and severe complications may occur. Extensive explorations of these conditions often include the search for antinuclear autoantibodies (ANA). Methods We analysed fluorescence patterns in the ANA test in patients with either chronic cryptic or acute symptomatic malaria, then conducted a one-year prospective study at a single hospital on all available sera drawn for ANA detections. We then identified autoantibodies differentially expressed in malaria patients and in controls using human protein microarray. Results We uncovered and defined a new, malaria-related, nucleo-cytoplasmic ANA pattern displaying the specific association of a nuclear speckled pattern with diffuse cytoplasmic perinuclearly-enhanced fluorescence. In the one-year prospective analysis, 79% of sera displaying this new nucleo-cytoplasmic fluorescence were from patients with malaria. This specific pattern, not seen in other parasitic diseases, allowed a timely reorientation of the diagnosis toward malaria. To assess if the autoantibody immune response was due to autoreactivity or molecular mimicry we isolated 42 autoantigens, targets of malarial autoantibodies. BLAST analysis indicated that 23 of recognized autoantigens were homologous to plasmodial proteins suggesting autoimmune responses directly driven by the plasmodial infection. Conclusion In patients with malaria in whom parasitological tests have not been performed recognition of this new, malaria-related fluorescence pattern on the ANA test is highly suggestive of the diagnosis and triggers immediate, easy confirmation and adapted therapy. PMID:24551116

  4. GMOtrack: generator of cost-effective GMO testing strategies.

    PubMed

    Novak, Petra Krau; Gruden, Kristina; Morisset, Dany; Lavrac, Nada; Stebih, Dejan; Rotter, Ana; Zel, Jana

    2009-01-01

    Commercialization of numerous genetically modified organisms (GMOs) has already been approved worldwide, and several additional GMOs are in the approval process. Many countries have adopted legislation to deal with GMO-related issues such as food safety, environmental concerns, and consumers' right of choice, making GMO traceability a necessity. The growing extent of GMO testing makes it important to study optimal GMO detection and identification strategies. This paper formally defines the problem of routine laboratory-level GMO tracking as a cost optimization problem, thus proposing a shift from "the same strategy for all samples" to "sample-centered GMO testing strategies." An algorithm (GMOtrack) for finding optimal two-phase (screening-identification) testing strategies is proposed. The advantages of cost optimization with increasing GMO presence on the market are demonstrated, showing that optimization approaches to analytic GMO traceability can result in major cost reductions. The optimal testing strategies are laboratory-dependent, as the costs depend on prior probabilities of local GMO presence, which are exemplified on food and feed samples. The proposed GMOtrack approach, publicly available under the terms of the General Public License, can be extended to other domains where complex testing is involved, such as safety and quality assurance in the food supply chain. PMID:20166592

  5. Massive alterations of the methylation patterns around DNA transposons in the first four generations of a newly formed wheat allohexaploid.

    PubMed

    Yaakov, Beery; Kashkush, Khalil

    2011-01-01

    Rapid and reproducible genomic changes can be induced during the early stages of the life of nascent allopolyploid species. In a previous study, it was shown that following allopolyploidization, cytosine methylation changes can affect up to 11% of the wheat genome. However, the methylation patterns around transposable elements (TEs) were never studied in detail. We used transposon methylation display (TMD) to assess the methylation patterns of CCGG sites flanking three TE families (Balduin, Apollo, and Thalos) in the first four generations of a newly formed wheat allohexaploid. In addition, transposon display (TD), using a methylation-insensitive restriction enzyme, was applied to search for genomic rearrangements at the TE insertion sites. We observed that up to 54% of CCGG sites flanking the three TE families showed changes in methylation patterns in the first four generations of a newly formed wheat allohexaploid, where hypermethylation was predominant. Over 70% of the changes in TMD patterns occurred in the first two generations of the newly formed allohexaploid. Furthermore, analysis of 555 TE insertion sites by TD and 18 cases by site-specific PCR revealed a full additive pattern in the allohexaploid, an indication for lack of massive rearrangements. These data indicate that following allopolyplodization, DNA-TE insertion sites can undergo a significantly high level of methylation changes compared with methylation changes of other genomic sequences. PMID:21217805

  6. Real-time biomimetic Central Pattern Generators in an FPGA for hybrid experiments

    PubMed Central

    Ambroise, Matthieu; Levi, Timothée; Joucla, Sébastien; Yvert, Blaise; Saïghi, Sylvain

    2013-01-01

    This investigation of the leech heartbeat neural network system led to the development of a low resources, real-time, biomimetic digital hardware for use in hybrid experiments. The leech heartbeat neural network is one of the simplest central pattern generators (CPG). In biology, CPG provide the rhythmic bursts of spikes that form the basis for all muscle contraction orders (heartbeat) and locomotion (walking, running, etc.). The leech neural network system was previously investigated and this CPG formalized in the Hodgkin–Huxley neural model (HH), the most complex devised to date. However, the resources required for a neural model are proportional to its complexity. In response to this issue, this article describes a biomimetic implementation of a network of 240 CPGs in an FPGA (Field Programmable Gate Array), using a simple model (Izhikevich) and proposes a new synapse model: activity-dependent depression synapse. The network implementation architecture operates on a single computation core. This digital system works in real-time, requires few resources, and has the same bursting activity behavior as the complex model. The implementation of this CPG was initially validated by comparing it with a simulation of the complex model. Its activity was then matched with pharmacological data from the rat spinal cord activity. This digital system opens the way for future hybrid experiments and represents an important step toward hybridization of biological tissue and artificial neural networks. This CPG network is also likely to be useful for mimicking the locomotion activity of various animals and developing hybrid experiments for neuroprosthesis development. PMID:24319408

  7. Designing responsive pattern generators: stable heteroclinic channel cycles for modeling and control.

    PubMed

    Horchler, Andrew D; Daltorio, Kathryn A; Chiel, Hillel J; Quinn, Roger D

    2015-04-01

    A striking feature of biological pattern generators is their ability to respond immediately to multisensory perturbations by modulating the dwell time at a particular phase of oscillation, which can vary force output, range of motion, or other characteristics of a physical system. Stable heteroclinic channels (SHCs) are a dynamical architecture that can provide such responsiveness to artificial devices such as robots. SHCs are composed of sequences of saddle equilibrium points, which yields exquisite sensitivity. The strength of the vector fields in the neighborhood of these equilibria determines the responsiveness to perturbations and how long trajectories dwell in the vicinity of a saddle. For SHC cycles, the addition of stochastic noise results in oscillation with a regular mean period. In this paper, we parameterize noise-driven Lotka-Volterra SHC cycles such that each saddle can be independently designed to have a desired mean sub-period. The first step in the design process is an analytic approximation, which results in mean sub-periods that are within 2% of the specified sub-period for a typical parameter set. Further, after measuring the resultant sub-periods over sufficient numbers of cycles, the magnitude of the noise can be adjusted to control the mean period with accuracy close to that of the integration step size. With these relationships, SHCs can be more easily employed in engineering and modeling applications. For applications that require smooth state transitions, this parameterization permits each state's distribution of periods to be independently specified. Moreover, for modeling context-dependent behaviors, continuously varying inputs in each state dimension can rapidly precipitate transitions to alter frequency and phase. PMID:25712192

  8. Neurochemical and Neuroanatomical Identification of Central Pattern Generator Neuron Homologues in Nudipleura Molluscs

    PubMed Central

    Lillvis, Joshua L.; Gunaratne, Charuni A.; Katz, Paul S.

    2012-01-01

    Certain invertebrate neurons can be identified by their behavioral functions. However, evolutionary divergence can cause some species to not display particular behaviors, thereby making it impossible to use physiological characteristics related to those behaviors for identifying homologous neurons across species. Therefore, to understand the neural basis of species-specific behavior, it is necessary to identify homologues using characteristics that are independent of physiology. In the Nudipleura mollusc Tritonia diomedea, Cerebral Neuron 2 (C2) was first described as being a member of the swim central pattern generator (CPG). Here we demonstrate that neurochemical markers, in conjunction with previously known neuroanatomical characteristics, allow C2 to be uniquely identified without the aid of electrophysiological measures. Specifically, C2 had three characteristics that, taken together, identified the neuron: 1) a white cell on the dorsal surface of the cerebral ganglion, 2) an axon that projected to the contralateral pedal ganglion and through the pedal commissure, and 3) immunoreactivity for the peptides FMRFamide and Small Cardioactive Peptide B. These same anatomical and neurochemical characteristics also uniquely identified the C2 homologue in Pleurobranchaea californica (called A1), which was previously identified by its analogous role in the Pleurobranchaea swim CPG. Furthermore, these characteristics were used to identify C2 homologues in Melibe leonina, Hermissenda crassicornis, and Flabellina iodinea, species that are phylogenetically closer to Tritonia than Pleurobranchaea, but do not display the same swimming behavior as Tritonia or Pleurobranchaea. These identifications will allow future studies comparing and contrasting the physiological properties of C2 across species that can and cannot produce the type of swimming behavior exhibited by Tritonia. PMID:22363716

  9. NEXT GENERATION SEDIMENT TOXICITY TESTING VIA DNA MICROARRAYS - PHASE I

    EPA Science Inventory

    The current SBIR solicitation states that the EPA is seeking “better sampling, analysis, and monitoring technologies” to improve hazardous waste management.  Development of new methods for testing contaminated sediments is an area of particular concern because many industri...

  10. 40 CFR 86.1333-90 - Transient test cycle generation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... test. The torque and rpm feedback signals may be filtered. (d) Idle Speed Enhancement Devices (e.g... feedback torque equal to zero (using, for example, clutch disengagement, speed to torque control switching... longer, the average feedback torque must be within ±10 ft-lbs of zero. To allow for transition, up to...

  11. Multiple hypotheses testing of fish incidence patterns in an urbanized ecosystem

    USGS Publications Warehouse

    Chizinski, C.J.; Higgins, C.L.; Shavlik, C.E.; Pope, K.L.

    2006-01-01

    Ecological and evolutionary theories have focused traditionally on natural processes with little attempt to incorporate anthropogenic influences despite the fact that humans are such an integral part of virtually all ecosystems. A series of alternate models that incorporated anthropogenic factors and traditional ecological mechanisms of invasion to account for fish incidence patterns in urban lakes was tested. The models were based on fish biology, human intervention, and habitat characteristics. However, the only models to account for empirical patterns were those that included fish invasiveness, which incorporated species-specific information about overall tolerance and fecundity. This suggests that species-specific characteristics are more important in general distributional patterns than human-mediated dispersal. Better information of illegal stocking activities is needed to improve human-mediated models, and more insight into basic life history of ubiquitous species is needed to truly understand underlying mechanisms of biotic homogenization. ?? Springer 2005.

  12. A novel approach to locomotion learning: Actor-Critic architecture using central pattern generators and dynamic motor primitives

    PubMed Central

    Li, Cai; Lowe, Robert; Ziemke, Tom

    2014-01-01

    In this article, we propose an architecture of a bio-inspired controller that addresses the problem of learning different locomotion gaits for different robot morphologies. The modeling objective is split into two: baseline motion modeling and dynamics adaptation. Baseline motion modeling aims to achieve fundamental functions of a certain type of locomotion and dynamics adaptation provides a “reshaping” function for adapting the baseline motion to desired motion. Based on this assumption, a three-layer architecture is developed using central pattern generators (CPGs, a bio-inspired locomotor center for the baseline motion) and dynamic motor primitives (DMPs, a model with universal “reshaping” functions). In this article, we use this architecture with the actor-critic algorithms for finding a good “reshaping” function. In order to demonstrate the learning power of the actor-critic based architecture, we tested it on two experiments: (1) learning to crawl on a humanoid and, (2) learning to gallop on a puppy robot. Two types of actor-critic algorithms (policy search and policy gradient) are compared in order to evaluate the advantages and disadvantages of different actor-critic based learning algorithms for different morphologies. Finally, based on the analysis of the experimental results, a generic view/architecture for locomotion learning is discussed in the conclusion. PMID:25324773

  13. A novel approach to locomotion learning: Actor-Critic architecture using central pattern generators and dynamic motor primitives.

    PubMed

    Li, Cai; Lowe, Robert; Ziemke, Tom

    2014-01-01

    In this article, we propose an architecture of a bio-inspired controller that addresses the problem of learning different locomotion gaits for different robot morphologies. The modeling objective is split into two: baseline motion modeling and dynamics adaptation. Baseline motion modeling aims to achieve fundamental functions of a certain type of locomotion and dynamics adaptation provides a "reshaping" function for adapting the baseline motion to desired motion. Based on this assumption, a three-layer architecture is developed using central pattern generators (CPGs, a bio-inspired locomotor center for the baseline motion) and dynamic motor primitives (DMPs, a model with universal "reshaping" functions). In this article, we use this architecture with the actor-critic algorithms for finding a good "reshaping" function. In order to demonstrate the learning power of the actor-critic based architecture, we tested it on two experiments: (1) learning to crawl on a humanoid and, (2) learning to gallop on a puppy robot. Two types of actor-critic algorithms (policy search and policy gradient) are compared in order to evaluate the advantages and disadvantages of different actor-critic based learning algorithms for different morphologies. Finally, based on the analysis of the experimental results, a generic view/architecture for locomotion learning is discussed in the conclusion. PMID:25324773

  14. TID Test Results for 4th Generation iPad(TradeMark)

    NASA Technical Reports Server (NTRS)

    Guertin, S. M.; Allen, G. R.; McClure, S. S.; LaBel, K. A.

    2013-01-01

    TID testing of 4th generation iPads is reported. Of iPad subsystems, results indicate that the charging circuitry and display drivers fail at lowest TID levels. Details of construction are investigated for additional testing of components.

  15. Testing Independent Component Patterns by Inter-Subject or Inter-Session Consistency

    PubMed Central

    Hyvärinen, Aapo; Ramkumar, Pavan

    2013-01-01

    Independent component analysis (ICA) is increasingly used to analyze patterns of spontaneous activity in brain imaging. However, there are hardly any methods for answering the fundamental question: are the obtained components statistically significant? Most methods considering the significance of components either consider group-differences or use arbitrary thresholds with weak statistical justification. In previous work, we proposed a statistically principled method for testing if the coefficients in the mixing matrix are similar in different subjects or sessions. In many applications of ICA, however, we would like to test the reliability of the independent components themselves and not the mixing coefficients. Here, we develop a test for such an inter-subject consistency by extending our previous theory. The test is applicable, for example, to the spatial activity patterns obtained by spatial ICA in resting-state fMRI. We further improve both this and the previously proposed testing method by introducing a new way of correcting for multiple testing, new variants of the clustering method, and a computational approximation which greatly reduces the memory and computation required. PMID:23525229

  16. Understanding Referral Patterns for Bone Mineral Density Testing among Family Physicians: A Qualitative Descriptive Study

    PubMed Central

    Munce, Sarah E. P.; Allin, Sonya; Carlin, Leslie; Sale, Joanna; Hawker, Gillian; Kim, Sandra; Butt, Debra A.; Polidoulis, Irene; Tu, Karen; Jaglal, Susan B.

    2016-01-01

    Introduction. Evidence of inappropriate bone mineral density (BMD) testing has been identified in terms of overtesting in low risk women and undertesting among patients at high risk. In light of these phenomena, the objective of this study was to understand the referral patterns for BMD testing among Ontario's family physicians (FPs). Methods. A qualitative descriptive approach was adopted. Twenty-two FPs took part in a semi-structured interview lasting approximately 30 minutes. An inductive thematic analysis was performed on the transcribed data in order to understand the referral patterns for BMD testing. Results. We identified a lack of clarity about screening for osteoporosis with a tendency for baseline BMD testing in healthy, postmenopausal women and a lack of clarity on the appropriate age for screening for men in particular. A lack of clarity on appropriate intervals for follow-up testing was also described. Conclusions. These findings lend support to what has been documented at the population level suggesting a tendency among FPs to refer menopausal women (at low risk). Emphasis on referral of high-risk groups as well as men and further clarification and education on the appropriate intervals for follow-up testing is warranted. PMID:26904357

  17. Roles for Multifunctional and Specialized Spinal Interneurons During Motor Pattern Generation in Tadpoles, Zebrafish Larvae, and Turtles

    PubMed Central

    Berkowitz, Ari; Roberts, Alan; Soffe, Stephen R.

    2010-01-01

    The hindbrain and spinal cord can produce multiple forms of locomotion, escape, and withdrawal behaviors and (in limbed vertebrates) site-specific scratching. Until recently, the prevailing view was that the same classes of central nervous system neurons generate multiple kinds of movements, either through reconfiguration of a single, shared network or through an increase in the number of neurons recruited within each class. The mechanisms involved in selecting and generating different motor patterns have recently been explored in detail in some non-mammalian, vertebrate model systems. Work on the hatchling Xenopus tadpole, the larval zebrafish, and the adult turtle has now revealed that distinct kinds of motor patterns are actually selected and generated by combinations of multifunctional and specialized spinal interneurons. Multifunctional interneurons may form a core, multipurpose circuit that generates elements of coordinated motor output utilized in multiple behaviors, such as left-right alternation. But, in addition, specialized spinal interneurons including separate glutamatergic and glycinergic classes are selectively activated during specific patterns: escape-withdrawal, swimming and struggling in tadpoles and zebrafish, and limb withdrawal and scratching in turtles. These specialized neurons can contribute by changing the way central pattern generator (CPG) activity is initiated and by altering CPG composition and operation. The combined use of multifunctional and specialized neurons is now established as a principle of organization across a range of vertebrates. Future research may reveal common patterns of multifunctionality and specialization among interneurons controlling diverse movements and whether similar mechanisms exist in higher-order brain circuits that select among a wider array of complex movements. PMID:20631847

  18. Development and tests of experimental solar generators for concentrating systems

    NASA Astrophysics Data System (ADS)

    Gochermann, H.; Muehle, H.

    1981-10-01

    Terrestrial photovoltaic generators were developed for integration into a hybrid system designed to demonstrate cost reduction of photovoltaic systems by concentration of sunlight. The photovoltaic cells consist of monocrystalline silicon, n-p type, 5 by 5 sq cm large and 0.35 mm thick. The antireflection layer is made of TiOx and the contact system of passivated Ti(Pd)Ag. Usage of low ohmic materials and decrease of contact resistance by deeper n-diffusion allows for maintaining cell efficiency almost constant for intensities up to 0.2 W per sq cm. The layout of several hybrid systems using parabolic reflectors is given and the mounting of the solar cells is illustrated.

  19. Parametric Analysis of a Hover Test Vehicle using Advanced Test Generation and Data Analysis

    NASA Technical Reports Server (NTRS)

    Gundy-Burlet, Karen; Schumann, Johann; Menzies, Tim; Barrett, Tony

    2009-01-01

    Large complex aerospace systems are generally validated in regions local to anticipated operating points rather than through characterization of the entire feasible operational envelope of the system. This is due to the large parameter space, and complex, highly coupled nonlinear nature of the different systems that contribute to the performance of the aerospace system. We have addressed the factors deterring such an analysis by applying a combination of technologies to the area of flight envelop assessment. We utilize n-factor (2,3) combinatorial parameter variations to limit the number of cases, but still explore important interactions in the parameter space in a systematic fashion. The data generated is automatically analyzed through a combination of unsupervised learning using a Bayesian multivariate clustering technique (AutoBayes) and supervised learning of critical parameter ranges using the machine-learning tool TAR3, a treatment learner. Covariance analysis with scatter plots and likelihood contours are used to visualize correlations between simulation parameters and simulation results, a task that requires tool support, especially for large and complex models. We present results of simulation experiments for a cold-gas-powered hover test vehicle.

  20. Aging and Generational Patterns of Alcohol Consumption among Mexican Americans, Cuban Americans and Mainland Puerto Ricans.

    ERIC Educational Resources Information Center

    Black, Sandra A.; Markides, Kyriakos S.

    1994-01-01

    Used data from Hispanic Health and Nutrition Examination Survey to describe life-course patterns of alcohol consumption among Mexican Americans, Cuban Americans, and Puerto Ricans residing in mainland United States. Found age differences in patterns of consumption among Mexican American and Puerto Rican males that reflect aging effects. Found…

  1. Extreme ultraviolet lithography patterned mask defect detection performance evaluation toward 16- to 11-nm half-pitch generation

    NASA Astrophysics Data System (ADS)

    Hirano, Ryoichi; Iida, Susumu; Amano, Tsuyoshi; Watanabe, Hidehiro; Hatakeyama, Masahiro; Murakami, Takeshi; Yoshikawa, Shoji; Terao, Kenji

    2015-07-01

    High-sensitivity and low-noise extreme ultraviolet (EUV) mask pattern defect detection is one of the major issues remaining to be addressed in device fabrication using extreme ultraviolet lithography (EUVL). We have designed a projection electron microscopy (PEM) system, which has proven to be quite promising for half-pitch (hp) 16-nm node to hp 11-nm node mask inspection. The PEM system was integrated into a pattern inspection system for defect detection sensitivity evaluation. To improve the performance of hp 16-nm patterned mask defect detection toward hp 11-nm EUVL patterned mask, defect detection signal characteristics, which depend on hp 64-nm pattern image intensity deviation on EUVL mask, were studied. Image adjustment effect of the captured images for die-to-die defect detection was evaluated before the start of the defect detection image-processing sequence. Image correction of intrafield intensity unevenness and L/S pattern image contrast deviation suppresses the generation of false defects. Captured images of extrusion and intrusion defects in hp 64-nm L/S patterns were used for detection. Applying the image correction for defect detection, 12-nm sized intrusion defect, which was smaller than our target size for hp 16-nm defect detection requirements, was identified without false defects.

  2. Generating Random Parallel Test Forms Using CTT in a Computer-Based Environment.

    ERIC Educational Resources Information Center

    Weiner, John A.; Gibson, Wade M.

    1998-01-01

    Describes a procedure for automated-test-forms assembly based on Classical Test Theory (CTT). The procedure uses stratified random-content sampling and test-form preequating to ensure both content and psychometric equivalence in generating virtually unlimited parallel forms. Extends the usefulness of CTT in automated test construction. (Author/SLD)

  3. Next-generation automatic test equipment for military support

    NASA Astrophysics Data System (ADS)

    Wasserman, M.

    The underlying philosophy and design of automatic testing equipment (ATE) for military systems have undergone modification in view of the increasingly important requirement of forward deployment. ATE stations must accordingly become smaller and lighter for the sake of transportability, as well as hardier and easily reconfigurable. Ease of operation and maintenance also become critical. Among the technologies identified as essential for the implementation of these stringent ATE design requirements are the IEE-488, MIL-STD-1553, VME, VXI, and SCSI data buses, 'instruments on a card' technology, optical disk drives, touch-screen technology, and expert system-related software.

  4. Plant species richness belowground: higher richness and new patterns revealed by next-generation sequencing.

    PubMed

    Hiiesalu, Inga; Opik, Maarja; Metsis, Madis; Lilje, Liisa; Davison, John; Vasar, Martti; Moora, Mari; Zobel, Martin; Wilson, Scott D; Pärtel, Meelis

    2012-04-01

    Variation in plant species richness has been described using only aboveground vegetation. The species richness of roots and rhizomes has never been compared with aboveground richness in natural plant communities. We made direct comparisons of grassland plant richness in identical volumes (0.1 × 0.1 × 0.1 m) above and below the soil surface, using conventional species identification to measure aboveground richness and 454 sequencing of the chloroplast trnL(UAA) intron to measure belowground richness. We described above- and belowground richness at multiple spatial scales (from a neighbourhood scale of centimetres to a community scale of hundreds of metres), and related variation in richness to soil fertility. Tests using reference material indicated that 454 sequencing captured patterns of species composition and abundance with acceptable accuracy. At neighbourhood scales, belowground richness was up to two times greater than aboveground richness. The relationship between above- and belowground richness was significantly different from linear: beyond a certain level of belowground richness, aboveground richness did not increase further. Belowground richness also exceeded that of aboveground at the community scale, indicating that some species are temporarily dormant and absent aboveground. Similar to other grassland studies, aboveground richness declined with increasing soil fertility; in contrast, the number of species found only belowground increased significantly with fertility. These results indicate that conventional aboveground studies of plant richness may overlook many coexisting species, and that belowground richness becomes relatively more important in conditions where aboveground richness decreases. Measuring plant belowground richness can considerably alter perceptions of biodiversity and its responses to natural and anthropogenic factors. PMID:22168247

  5. DESIGN, FABRICATION, AND TESTING OF AN ADVANCED, NON-POLLUTING TURBINE DRIVE GAS GENERATOR

    SciTech Connect

    E.W. Baxter

    2002-06-30

    The objective of this report period was to continue the development of the Gas Generator design, completion of the hardware and ancillary hardware fabrication and commence the Test Preparations for the testing of the non-polluting unique power turbine driven Gas Generator. Focus during this report period has been on completing the Gas Generator fabrication of hardware and ancillary hardware, and completion of unit closeout brazing and bonding. Because of unacceptable delays encountered in a previously competitively selected test site, CES initiated a re-competition of our testing program and selected an alternate test site. Following that selection, CES used all available resources to make preparations for testing the 10 Mw Gas Generator at the new testing site facilities of NTS at Saugus, CA.

  6. Pattern recognition techniques for failure trend detection in SSME ground tests

    NASA Technical Reports Server (NTRS)

    Choudry, A.

    1987-01-01

    The Space Shuttle Main Engine (SSME) is a complex power plant. To evaluate its performance 1200 hot-wire ground tests have been conducted, varying in duration from 0 to 500 secs. During the test some 500 sensors are sampled every 20 ms. The sensors are generally bounded by red lines so that an excursion beyond could lead to premature shutdown. In 27 tests it was not possible to effect an orderly premature shutdown, resulting in major incidents with serious damage to the SSME and test stand. The application of pattern recognition are investigated to detect SSME performance trends that may lead to major incidents. Based on the sensor data a set of (n) features is defined. At any time during the test, the state of the SSME is given by a point in the n-dimensional feature space. The history of a test can now be represented as a trajectory in the n-dimensional feature space. Portions of the normal trajectories and failed test trajectories would lie in different regions of the n-dimensional feature space. The latter can now be partitioned into regions of normal and failed tests. Thus, it is possible to examine the trajectory of a test in progress and predict if it is going into the normal or failure region.

  7. A sequential nonparametric pattern classification algorithm based on the Wald SPRT. [Sequential Probability Ratio Test

    NASA Technical Reports Server (NTRS)

    Poage, J. L.

    1975-01-01

    A sequential nonparametric pattern classification procedure is presented. The method presented is an estimated version of the Wald sequential probability ratio test (SPRT). This method utilizes density function estimates, and the density estimate used is discussed, including a proof of convergence in probability of the estimate to the true density function. The classification procedure proposed makes use of the theory of order statistics, and estimates of the probabilities of misclassification are given. The procedure was tested on discriminating between two classes of Gaussian samples and on discriminating between two kinds of electroencephalogram (EEG) responses.

  8. Computerized in vitro test for chemical toxicity based on tetrahymena swimming patterns

    NASA Technical Reports Server (NTRS)

    Noever, David A.; Matsos, Helen C.; Cronise, Raymond J.; Looger, Loren L.; Relwani, Rachna A.; Johnson, Jacqueline U.

    1994-01-01

    An apparatus and method for rapidly determining chemical toxicity was evaluated. The toxicity monitor includes an automated scoring of how motile biological cells (Tetrahymena pyriformis) slow down or otherwise change their swimming patterns in a hostile chemical environment. The device, called the Motility Assay Apparatus (MAA) is tested for 30 second determination of chemical toxicity in 20 aqueous samples containing trace organics and salts. With equal or better detection limits, results compare favorably to in vivo animal tests of eye irritancy, in addition to agreeing for all chemicals with previous manual evaluations of single cell motility.

  9. 78 FR 53483 - Inspections, Tests, Analyses, and Acceptance Criteria; Vogtle Electric Generating Plant, Unit 3

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-29

    ... COMMISSION Inspections, Tests, Analyses, and Acceptance Criteria; Vogtle Electric Generating Plant, Unit 3... acceptance criteria are met for ITAAC E.2.5.04.05.05.02, for the Vogtle Electric Generating Plant, Unit 3... specified acceptance criteria are met for Vogtle ] Electric Generating Plant, Unit 3 (ADAMS Accession...

  10. 78 FR 53484 - Inspections, Tests, Analyses, and Acceptance Criteria; Vogtle Electric Generating Plant, Unit 4

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-29

    ... COMMISSION Inspections, Tests, Analyses, and Acceptance Criteria; Vogtle Electric Generating Plant, Unit 4... acceptance criteria are met for ITAAC E.2.5.04.05.05.02, for the Vogtle Electric Generating Plant, Unit 4... specified acceptance criteria are met for Vogtle Electric Generating Plant, Unit 4 (ADAMS Accession...

  11. CD-ROM Based Multimedia Homework Solutions and Self Test Generator.

    ERIC Educational Resources Information Center

    Rhodes, Jeffrey M.; Bell, Christopher C.

    1998-01-01

    Discusses a prototype multimedia application that was designed to help college students solve problems and generate practice tests for an economics textbook. Highlights include step-by-step problem solving; a friendly interface; student tracking; inexpensive development costs; examples of screen displays; and generating random, scored tests on…

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

    ERIC Educational Resources Information Center

    Gierl, Mark J.; Lai, Hollis

    2013-01-01

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

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

    ERIC Educational Resources Information Center

    Gierl, Mark J.; Lai, Hollis

    2013-01-01

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

  14. Coincident steam generator tube rupture and stuck-open safety relief valve carryover tests: MB-2 steam generator transient response test program

    SciTech Connect

    Garbett, K; Mendler, O J; Gardner, G C; Garnsey, R; Young, M Y

    1987-03-01

    In PWR steam generator tube rupture (SGTR) faults, a direct pathway for the release of radioactive fission products can exist if there is a coincident stuck-open safety relief valve (SORV) or if the safety relief valve is cycled. In addition to the release of fission products from the bulk steam generator water by moisture carryover, there exists the possibility that some primary coolant may be released without having first mixed with the bulk water - a process called primary coolant bypassing. The MB-2 Phase II test program was designed specifically to identify the processes for droplet carryover during SGTR faults and to provide data of sufficient accuracy for use in developing physical models and computer codes to describe activity release. The test program consisted of sixteen separate tests designed to cover a range of steady-state and transient fault conditions. These included a full SGTR/SORV transient simulation, two SGTR overfill tests, ten steady-state SGTR tests at water levels ranging from very low levels in the bundle up to those when the dryer was flooded, and three moisture carryover tests without SGTR. In these tests the influence of break location and the effect of bypassing the dryer were also studied. In a final test the behavior with respect to aerosol particles in a dry steam generator, appropriate to a severe accident fault, was investigated.

  15. Vocal behavior and vocal central pattern generator organization diverge among toadfishes.

    PubMed

    Chagnaud, Boris P; Bass, Andrew H

    2014-01-01

    Among fishes, acoustic communication is best studied in toadfishes, a single order and family that includes species commonly known as toadfish and midshipman. However, there is a lack of comparative anatomical and physiological studies, making it difficult to identify both shared and derived mechanisms of vocalization among toadfishes. Here, vocal nerve labeling and intracellular in vivo recording and staining delineated the hindbrain vocal network of the Gulf toadfish Opsanus beta. Dextran-biotin labeling of the vocal nerve or intracellular neurobiotin fills of motoneurons delineated a midline vocal motor nucleus (VMN). Motoneurons showed bilaterally extensive dendritic arbors both within and lateral to the paired motor nuclei. The motoneuron activity matched that of the spike-like vocal nerve motor volley that determines the natural call duration and frequency. Ipsilateral vocal nerve labeling with biocytin or neurobiotin yielded dense bilateral transneuronal filling of motoneurons and coextensive columns of premotor neurons. These premotor neurons generated pacemaker-like action potentials matched 1:1 with vocal nerve and motoneuron firing. Transneuronal transport further revealed connectivity within and between the pacemaker-motor circuit and a rostral prepacemaker nucleus. Unlike the pacemaker-motor circuit, prepacemaker firing did not match the frequency of vocal nerve activity but instead was predictive of the duration of the vocal nerve volley that codes for call duration. Transneuronally labeled terminal-like boutons also occurred in auditory-recipient hindbrain nuclei, including neurons innervating the inner ear and lateral line organs. Together with studies of midshipman, we propose that separate premotor populations coding vocal frequency and duration with direct premotor coupling to auditory-lateral line nuclei are plesiomorphic characters for toadfishes. Unlike in midshipman, transneuronal labeling in toadfishes reveals an expansive column of pacemaker neurons that is weakly coupled to prepacemaker neurons, a character that likely depends on the extent of gap junction coupling. We propose that these and other anatomical characters contribute to neurophysiological properties that, in turn, sculpt the species-typical patterning of frequency and amplitude-modulated vocalizations. PMID:25115796

  16. Gas Generation Testing of Neptunium Oxide Generated Using the HB-Line Phase IIFlowsheet

    SciTech Connect

    Duffey, J

    2003-08-29

    The hydrogen (H{sub 2}) gas generation rate for neptunium dioxide (NpO{sub 2}) samples produced on a laboratory scale using the HB-Line Phase II flowsheet has been measured following exposure to 75% relative humidity (RH). As expected, the observed H{sub 2} generation rates for these samples increase with increasing moisture content. A maximum H{sub 2} generation rate of 1.8 x 10{sup -6} moles per day per kilogram (mol {center_dot} day{sup -1} kg{sup -1}) was observed for NpO{sub 2} samples with approximately one and one-half times (1 1/2 X) the expected specific surface area (SSA) for the HB-Line Phase II product. The SSA of NpO{sub 2} samples calcined at 650 C is similar to plutonium dioxide (PuO{sub 2}) calcined at 950 C according to the Department of Energy (DOE) standard for packaging and storage of PuO{sub 2}. This low SSA of the HB-Line Phase II product limits moisture uptake to less than 0.2 weight percent (wt %) even with extended exposure to 75% RH.

  17. Tsallis threshold analysis of digital speckle patterns generated by rough surfaces

    NASA Astrophysics Data System (ADS)

    Soares, H. C.; Meireles, J. B.; Castro, A. O.; Huguenin, J. A. O.; Schmidt, A. G. M.; da Silva, L.

    2015-08-01

    In this work we report on a study of entropic threshold of digital speckle patterns images produced by rough surfaces using Tsallis entropy. The speckle pattern images were obtained in the diffraction plane at the normal direction and they are the outcome of the incidence of a laser beam in the rough metallic surfaces. The speckle pattern images were segmented in order to verify the sensitivity of the optimal Tsallis entropic threshold value as a function of the surface roughness. We show that the surface roughness can be sensed and tuned by this method.

  18. Functional test generation for digital circuits described with a declarative language: LUSTRE

    NASA Astrophysics Data System (ADS)

    Almahrous, Mazen

    1990-08-01

    A functional approach to the test generation problem starting from a high level description is proposed. The circuit tested is modeled, using the LUSTRE high level data flow description language. The different LUSTRE primitives are translated to a SATAN format graph in order to evaluate the testability of the circuit and to generate test sequences. Another method of testing the complex circuits comprising an operative part and a control part is defined. It consists of checking experiments for the control part observed through the operative part. It was applied to the automata generated from a LUSTRE description of the circuit.

  19. Relating HIV testing patterns in Poland to risky and protective behaviour.

    PubMed

    Rosińska, Magdalena; Simmons, Ruth; Marzec-Bogusławska, Anna; Janiec, Janusz; Porter, Kholoud

    2016-04-01

    The aim of the study was to understand HIV testing patterns needed to improve access to early HIV diagnosis, and to investigate the spread of the virus in different populations. We examined prior testing history of individuals presenting for an HIV test across all 30 voluntary testing and counselling sites in Poland, 2008-2010 to determine factors associated with the testing rate using zero-truncated Poisson regression. Of 2397 persons presenting for an HIV test, 25 (1%) were HIV positive and 470 (19.6%) were repeat testers. The proportion of repeat testers was higher among men who have sex with men (MSM) at 37% (90/246), and people who inject drugs (PWID) at 32% (21/65). Higher testing rate was independently associated with exposure category (testing rate ratio, RR for MSM = 2.0, 95% CI 1.6-2.6, and 1.6, 0.9-2.6 for PWID), >5 sex partners (1.9, 1.4-2.7), high-risk partner (1.3, 1.1-1.6), urban residence (2.1, 1.3-3.5) and higher education attainment (1.1, 1.0-1.5). Inconsistent condom use with casual partners and sex under the influence of alcohol were associated with lower testing rates. There is a need to increase HIV testing uptake in Poland, especially among the rural population. Despite testing rates being higher among populations with higher risk of exposure to HIV (MSM and PWID), they still remain low, indicating the existence of barriers to testing. PMID:26559856

  20. Patterned mask inspection technology with Projection Electron Microscope (PEM) technique for 11 nm half-pitch (hp) generation EUV masks

    NASA Astrophysics Data System (ADS)

    Hirano, Ryoichi; Iida, Susumu; Amano, Tsuyoshi; Watanabe, Hidehiro; Hatakeyama, Masahiro; Murakami, Takeshi; Yoshikawa, Shoji; Suematsu, Kenichi; Terao, Kenji

    2015-07-01

    High-sensitivity EUV mask pattern defect detection is one of the major issues in order to realize the device fabrication by using the EUV lithography. We have already designed a novel Projection Electron Microscope (PEM) optics that has been integrated into a new inspection system named EBEYE-V30 ("Model EBEYE" is an EBARA's model code), and which seems to be quite promising for 16 nm hp generation EUVL Patterned mask Inspection (PI). Defect inspection sensitivity was evaluated by capturing an electron image generated at the mask by focusing onto an image sensor. The progress of the novel PEM optics performance is not only about making an image sensor with higher resolution but also about doing a better image processing to enhance the defect signal. In this paper, we describe the experimental results of EUV patterned mask inspection using the above-mentioned system. The performance of the system is measured in terms of defect detectability for 11 nm hp generation EUV mask. To improve the inspection throughput for 11 nm hp generation defect detection, it would require a data processing rate of greater than 1.5 Giga- Pixel-Per-Second (GPPS) that would realize less than eight hours of inspection time including the step-and-scan motion associated with the process. The aims of the development program are to attain a higher throughput, and enhance the defect detection sensitivity by using an adequate pixel size with sophisticated image processing resulting in a higher processing rate.

  1. Control strategies of 3-cell Central Pattern Generator via global stimuli.

    PubMed

    Lozano, Álvaro; Rodríguez, Marcos; Barrio, Roberto

    2016-01-01

    The study of the synchronization patterns of small neuron networks that control several biological processes has become an interesting growing discipline. Some of these synchronization patterns of individual neurons are related to some undesirable neurological diseases, and they are believed to play a crucial role in the emergence of pathological rhythmic brain activity in different diseases, like Parkinson's disease. We show how, with a suitable combination of short and weak global inhibitory and excitatory stimuli over the whole network, we can switch between different stable bursting patterns in small neuron networks (in our case a 3-neuron network). We develop a systematic study showing and explaining the effects of applying the pulses at different moments. Moreover, we compare the technique on a completely symmetric network and on a slightly perturbed one (a much more realistic situation). The present approach of using global stimuli may allow to avoid undesirable synchronization patterns with nonaggressive stimuli. PMID:27021970

  2. Control strategies of 3-cell Central Pattern Generator via global stimuli

    PubMed Central

    Lozano, Álvaro; Rodríguez, Marcos; Barrio, Roberto

    2016-01-01

    The study of the synchronization patterns of small neuron networks that control several biological processes has become an interesting growing discipline. Some of these synchronization patterns of individual neurons are related to some undesirable neurological diseases, and they are believed to play a crucial role in the emergence of pathological rhythmic brain activity in different diseases, like Parkinson’s disease. We show how, with a suitable combination of short and weak global inhibitory and excitatory stimuli over the whole network, we can switch between different stable bursting patterns in small neuron networks (in our case a 3-neuron network). We develop a systematic study showing and explaining the effects of applying the pulses at different moments. Moreover, we compare the technique on a completely symmetric network and on a slightly perturbed one (a much more realistic situation). The present approach of using global stimuli may allow to avoid undesirable synchronization patterns with nonaggressive stimuli.

  3. Automatic Generation of Rasch-Calibrated Items: Figural Matrices Test GEOM and Endless-Loops Test EC

    ERIC Educational Resources Information Center

    Arendasy, Martin

    2005-01-01

    The future of test construction for certain psychological ability domains that can be analyzed well in a structured manner may lie--at the very least for reasons of test security--in the field of automatic item generation. In this context, a question that has not been explicitly addressed is whether it is possible to embed an item response theory…

  4. Automatic Generation of Rasch-Calibrated Items: Figural Matrices Test GEOM and Endless-Loops Test EC

    ERIC Educational Resources Information Center

    Arendasy, Martin

    2005-01-01

    The future of test construction for certain psychological ability domains that can be analyzed well in a structured manner may lie--at the very least for reasons of test security--in the field of automatic item generation. In this context, a question that has not been explicitly addressed is whether it is possible to embed an item response theory…

  5. Genetic Algorithm-Based Test Data Generation for Multiple Paths via Individual Sharing

    PubMed Central

    Gong, Dunwei

    2014-01-01

    The application of genetic algorithms in automatically generating test data has aroused broad concerns and obtained delightful achievements in recent years. However, the efficiency of genetic algorithm-based test data generation for path testing needs to be further improved. In this paper, we establish a mathematical model of generating test data for multiple paths coverage. Then, a multipopulation genetic algorithm with individual sharing is presented to solve the established model. We not only analyzed the performance of the proposed method theoretically, but also applied it to various programs under test. The experimental results show that the proposed method can improve the efficiency of generating test data for many paths' coverage significantly. PMID:25691894

  6. Use of the Society of Motion Picture and Television Engineers test pattern in picture archiving and communication systems (PACS)

    NASA Astrophysics Data System (ADS)

    Gray, Joel E.

    1991-05-01

    In 1985 the Society of Motion Picture and Television Engineers (SMPTE) published a Recommended Practice (RP-133) entitled Specifications for Medical Diagnostic Imaging Test Pattern for Television Monitors and Hard-copy Cameras. Since that time the SMPTE monochrome test pattern has been applied to the acceptance testing and quality control of video and image display systems, and hard-copy (film) recorders. The major features of the test pattern will be discussed along with applications and the problems demonstrated with the pattern. Furthermore, the test pattern will be used to demonstrate that color displays may exhibit only one-half of the resolution of a monochrome monitor while the display contrast (due to limited dynamic range) may be only 10 to 20 of that obtained with a monochrome display.

  7. Differences in Walking Pattern during 6-Min Walk Test between Patients with COPD and Healthy Subjects

    PubMed Central

    Annegarn, Janneke; Spruit, Martijn A.; Savelberg, Hans H. C. M.; Willems, Paul J. B.; van Bool, Coby; Schols, Annemie M. W. J.; Wouters, Emiel F. M.; Meijer, Kenneth

    2012-01-01

    Background To date, detailed analyses of walking patterns using accelerometers during the 6-min walk test (6MWT) have not been performed in patients with chronic obstructive pulmonary disease (COPD). Therefore, it remains unclear whether and to what extent COPD patients have an altered walking pattern during the 6MWT compared to healthy elderly subjects. Methodology/Principal Findings 79 COPD patients and 24 healthy elderly subjects performed the 6MWT wearing an accelerometer attached to the trunk. The accelerometer features (walking intensity, cadence, and walking variability) and subject characteristics were assessed and compared between groups. Moreover, associations were sought with 6-min walk distance (6MWD) using multiple ordinary least squares (OLS) regression models. COPD patients walked with a significantly lower walking intensity, lower cadence and increased walking variability compared to healthy subjects. Walking intensity and height were the only two significant determinants of 6MWD in healthy subjects, explaining 85% of the variance in 6MWD. In COPD patients also age, cadence, walking variability measures and their interactions were included were significant determinants of 6MWD (total variance in 6MWD explained: 88%). Conclusions/Significance COPD patients have an altered walking pattern during 6MWT compared to healthy subjects. These differences in walking pattern partially explain the lower 6MWD in patients with COPD. PMID:22624017

  8. Alternatives Generation and Analysis for Lower Knuckle Ultrasonic Testing Technology

    SciTech Connect

    WOLFF, J.J.

    2001-02-21

    Environmental regulations applicable to the River Protection Project require integrity assessment of the double-shell tank (DST) system. In the early 1990s a strategy and plans were developed to conduct the required tank system examinations and integrity assessments. This included plans to conduct ultrasonic testing of six DSTs. In 1997, an ad hoc committee (Tank Structural Integrity Panel, TSIP) working under the direction of the Office of Environmental Restoration and Waste Management, U.S. Department of Energy, published guidelines for managing risks associated with aging degradation of high level waste storage tanks. This included recommendations on non-destructive examination of specific regions of tanks. For the lower knuckle region, defined as the curved transition from the vertical portion of the tank wall to the flat portion of the tank bottom, the TSIP guidelines contained the following recommendation: ''Examine the lower knuckle region including 5% of the length of the upper weld, at least 2.5% of the area of the predicted maximum stress region of the knuckle base metal and 2.5% of the lower weld if accessible. Emphasis should be on weld/HAZ cracking such as SCC. If the lower weld is not accessible, one-square-foot sections whose length adds up to 5% of the circumference of the knuckle base metal shall be examined.'' Also in 1997, the U.S. Department of Energy and Washington Department of Ecology formalized an agreement on the DST system integrity assessment work scope required to satisfy the applicable regulatory requirements. This cited the TSIP guidelines, and included an agreement to conduct ultrasonic examination on six representative DSTs for determination and extent of cracks, corrosion, and pitting.

  9. An unsupervised pattern recognition approach for AE data originating from fatigue tests on polymer-composite materials

    NASA Astrophysics Data System (ADS)

    Doan, D. D.; Ramasso, E.; Placet, V.; Zhang, S.; Boubakar, L.; Zerhouni, N.

    2015-12-01

    This work investigates acoustic emission generated during tension fatigue tests carried out on a carbon fiber reinforced polymer (CFRP) composite specimen. Since massive fatigue data processing, especially noise reduction, remains an important challenge in AE data analysis, a Mahalanobis distance-based noise modeling has been proposed in the present work to tackle this problem. A sequential feature selection based on Davies-Bouldin index has been implemented for fast dimensionality reduction. An unsupervised classifier offline-learned from quasi-static data is then used to classify the data to different AE sources with the possibility to dynamically accommodate with unseen ones. With an efficient proposed noise removal and automatic separation of AE events, this pattern discovery procedure provides an insight into fatigue damage development in composites in the presence of millions of AE events.

  10. Rapid Generation of Multiplexed Cell Cocultures Using Acoustic Droplet Ejection Followed by Aqueous Two-Phase Exclusion Patterning

    PubMed Central

    Fang, Yu; Frampton, John P.; Raghavan, Shreya; Sabahi-Kaviani, Rahman; Luker, Gary

    2012-01-01

    The development of tools for patterning cocultures of cells is a fundamental interest among cell biologists and tissue engineers. Although a variety of systems exist for micropatterning cells, the methods used to generate cell micropatterns are often cumbersome and difficult to adapt for tissue engineering purposes. This study combines acoustic droplet ejection and aqueous two-phase system exclusion patterning to introduce a method for patterning cocultures of cells in multiplexed arrays. This new method uses focused acoustic radiation pressure to eject discrete droplets of uniform size from the surface of a dextran solution containing cells. The size of droplets is controlled by adjusting ultrasound parameters, such as pulse, duration, and amplitude. The ejected dextran droplets are captured on a cell culture substrate that is manipulated by a computer-controlled 3D positioning system according to predesigned patterns. Polyethylene glycol solution containing an additional cell type is then added to the culture dish to produce a two-phase system capable of depositing different types of cells around the initial pattern of cells. We demonstrate that our method can produce patterns of islands or lines with two or more cell types. Further, we demonstrate that patterns can be multiplexed for studies involving combinations of multiple cell types. This method offers a tool to transfer cell-containing samples in a contact-free, nozzle-less manner, avoiding sample cross-contamination. It can be used to pattern cell cocultures without complicated fabrication of culture substrates. These capabilities were used to examine the response of cancer cells to the presence of a ligand (CXCL12) secreted from surrounding cocultured cells. PMID:22356298

  11. 21 CFR 874.1120 - Electronic noise generator for audiometric testing.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1120 Electronic.... It is intended to introduce a masking noise into the non-test ear during an audiometric evaluation. The device minimizes the non-test ear's sensing of test tones and signals being generated for the...

  12. 21 CFR 874.1120 - Electronic noise generator for audiometric testing.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1120 Electronic.... It is intended to introduce a masking noise into the non-test ear during an audiometric evaluation. The device minimizes the non-test ear's sensing of test tones and signals being generated for the...

  13. 21 CFR 874.1120 - Electronic noise generator for audiometric testing.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1120 Electronic.... It is intended to introduce a masking noise into the non-test ear during an audiometric evaluation. The device minimizes the non-test ear's sensing of test tones and signals being generated for the...

  14. 21 CFR 874.1120 - Electronic noise generator for audiometric testing.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1120 Electronic.... It is intended to introduce a masking noise into the non-test ear during an audiometric evaluation. The device minimizes the non-test ear's sensing of test tones and signals being generated for the...

  15. 21 CFR 874.1120 - Electronic noise generator for audiometric testing.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1120 Electronic.... It is intended to introduce a masking noise into the non-test ear during an audiometric evaluation. The device minimizes the non-test ear's sensing of test tones and signals being generated for the...

  16. The Negative Testing and Negative Generation Effects Are Eliminated by Delay

    ERIC Educational Resources Information Center

    Mulligan, Neil W.; Peterson, Daniel J.

    2015-01-01

    Although retrieval often enhances subsequent memory (the testing effect), a negative testing effect has recently been documented in which prior retrieval harms later recall compared with restudying. The negative testing effect was predicated on the negative generation effect and the item-specific-relational framework. The present experiments…

  17. Design of a Facility to Test the Advanced Stirling Radioisotope Generator Engineering Unit

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Schreiber, Jeffrey G.; Oriti, Salvatore M.; Meer, David W.; Brace, Michael H.; Dugala, Gina

    2010-01-01

    The Advanced Stirling Radioisotope Generator (ASRG), a high efficiency generator, is being considered for space missions. An engineering unit, the ASRG engineering unit (EU), was designed and fabricated by Lockheed Martin under contract to the Department of Energy. This unit is currently under extended operation test at the NASA Glenn Research Center (GRC) to generate performance data and validate the life and reliability predictions for the generator and the Stirling convertors. A special test facility was designed and built for the ASRG EU. This paper summarizes details of the test facility design, including the mechanical mounting, heat-rejection system, argon system, control systems, and maintenance. The effort proceeded from requirements definition through design, analysis, build, and test. Initial testing and facility performance results are discussed.

  18. Mixed Methods Case Study of Generational Patterns in Responses to Shame and Guilt

    ERIC Educational Resources Information Center

    Ng, Tony

    2013-01-01

    Moral socialization and moral learning are antecedents of moral motivation. As many as 4 generations interact in workplace and education settings; hence, a deeper understanding of the moral motivation of members of those generations is needed. The purpose of this convergent mixed methods case study was to understand the moral motivation of 5…

  19. Performance testing of thermoelectric generators including Voyager and LES 8/9 flight results

    NASA Technical Reports Server (NTRS)

    Garvey, L.; Stapfer, G.

    1979-01-01

    Several thermoelectric generators ranging in output power from 0.5 to 155 W have been completed or are undergoing testing at JPL. These generators represent a wide range of technologies, using Bi2Te3, PbTe and SiGe thermoelectric materials. Several of these generators are of a developmental type, such as HPG S/N2, and others are representative of Transit and Multi-Hundred Watt (MHW) Technology. Representative flight performance data of LES 8/9 and Voyager RTG's are presented and compared with the DEGRA computer program based on the data observed from tests of SiGe couples, modules and MHW generators.

  20. Manipulation of micro-particles through optical interference patterns generated by integrated photonic devices.

    PubMed

    Hsu, Li-Chung; Chen, Te-Chang; Yang, Yao-Tsu; Huang, Chieh-Yang; Shen, Da-Wei; Chen, Ya-Tzu; Lee, Ming-Chang M

    2013-03-21

    Micro-particle transport and switch governed by guided-wave optical interference are presented. The optical interference, occurring in a directional coupler and a multi-mode interferometer made by inverted rib waveguides, results in a specific evanescent field dependent on wavelength. Through a detailed theoretical analysis, the field of induced optical force shows a correlative pattern associated with the evanescent field. Experimental results demonstrate that 10 μm polystyrene beads are propelled with a trajectory subject to the interference pattern accordingly. By launching different wavelengths, the polystyrene beads can be delivered to different output waveguide ports. Massive micro-particle manipulation is applicable. PMID:23364290

  1. A simple model for polar cap convection patterns and generation of theta auroras

    NASA Technical Reports Server (NTRS)

    Lyons, L. R.

    1985-01-01

    An addition of the uniform interplanetary magnetic field and the earth's dipole magnetic field is used to evaluate electric field convection patterns over the polar caps that result from solar wind flow across open geomagnetic field lines. The model also accounts for field-aligned patterns within, and auroral arcs across, the polar cap. The qualitative predictions derived from the model express the electric field magnitudes, aurora intensity, sunward and antisunward flow, and the dusk-side reversal of the convection field in terms of the x and y components of the interplanetary magnetic field.

  2. Generation of a reference radiation pattern of string instruments using automatic excitation and acoustic centering.

    PubMed

    Shabtai, Noam R; Behler, Gottfried; Vorländer, Michael

    2015-11-01

    Radiation patterns of musical instruments are important for the understanding of music perception in concert halls, and may be used to improve the plausibility of virtual acoustic systems. Many attempts have been performed to measure the spatial response of musical instruments using surrounding spherical microphone arrays with a limited number of microphones. This work presents a high-resolution spatial sampling of the radiation pattern of an electrically excited violin, and addresses technical problems that arise due to mechanical reasons of the excitation apparatus using acoustic centering. PMID:26627818

  3. Hydrogel thin film with swelling-induced wrinkling patterns for high-throughput generation of multicellular spheroids.

    PubMed

    Zhao, Ziqi; Gu, Jianjun; Zhao, Yening; Guan, Ying; Zhu, X X; Zhang, Yongjun

    2014-09-01

    Three-dimensional (3D) multicellular spheroids (MCSs) mimic the structure and function of real tissue much better than the conventional 2D cell monolayers, however, their application was severely hindered by difficulties in their generation. An ideal method for MCS fabrication should produce spheroids with narrow size distribution and allow for control over their size. The method should also be simple, cheap, and scalable. Here, we use patterned nonadhesive poly(2-hydroxyethyl methacrylate) hydrogel films to guide the self-assembly of cells. The films were fabricated directly in the wells of cell culture plates. They were patterned spontaneously by swelling in water, without the use of any template or specialized facilities. When cell suspension is added, the cells settle down by gravity to the bottom. Because of the presence of the wrinkling pattern composed of uniformed microcaves, the cells accumulate to the center of the microcaves and gradually self-assemble into MCSs. Using this method, monodisperse MCSs were generated. The size of the spheroids can be facilely controlled by the number of cells seeded. The method is compatible with the conventional monolayer cell culture method. Thousands of spheroids can be generated in a single well. We expect this method will pave the way for the application of MCSs in various biomedical areas. PMID:25072634

  4. Field Test Protocol. Standard Internal Load Generation for Unoccupied Test Homes

    SciTech Connect

    Fang, X.; Christensen, D.; Barker, G.; Hancock, E.

    2011-06-01

    This document describes a simple and general way to generate House Simulation Protocol (HSP)-consistent internal sensible and latent loads in unoccupied homes. It is newly updated based on recent experience, and provides instructions on how to calculate and set up the operational profiles in unoccupied homes. The document is split into two sections: how to calculate the internal load magnitude and schedule, and then what tools and methods should be used to generate those internal loads to achieve research goals.

  5. Field Test Protocol: Standard Internal Load Generation in Unoccupied Test Homes

    SciTech Connect

    Fang, X.; Christensen, D.; Barker, G.; Hancock, E.

    2011-06-01

    This document describes a simple and general way to generate House Simulation Protocol (HSP)-consistent internal sensible and latent loads in unoccupied homes. It is newly updated based on recent experience, and provides instructions on how to calculate and set up the operational profiles in unoccupied homes. The document is split into two sections: how to calculate the internal load magnitude and schedule, and then what tools and methods should be used to generate those internal loads to achieve research goals.

  6. Impact of cercal air currents on singing motor pattern generation in the cricket (Gryllus bimaculatus DeGeer).

    PubMed

    Jacob, Pedro F; Hedwig, Berthold

    2015-11-01

    The cercal system of crickets detects low-frequency air currents produced by approaching predators and self-generated air currents during singing, which may provide sensory feedback to the singing motor network. We analyzed the effect of cercal stimulation on singing motor pattern generation to reveal the response of a singing interneuron to predator-like signals and to elucidate the possible role of self-generated air currents during singing. In fictive singing males, we recorded an interneuron of the singing network while applying air currents to the cerci; additionally, we analyzed the effect of abolishing the cercal system in freely singing males. In fictively singing crickets, the effect of short air stimuli is either to terminate prematurely or to lengthen the interchirp interval, depending on their phase in the chirp cycle. Within our stimulation paradigm, air stimuli of different velocities and durations always elicited an inhibitory postsynaptic potential in the singing interneuron. Current injection in the singing interneuron elicited singing motor activity, even during the air current-evoked inhibitory input from the cercal pathway. The disruptive effects of air stimuli on the fictive singing pattern and the inhibitory response of the singing interneuron point toward the cercal system being involved in initiating avoidance responses in singing crickets, according to the established role of cerci in a predator escape pathway. After abolishing the activity of the cercal system, the timing of natural singing activity was not significantly altered. Our study provides no evidence that self-generated cercal sensory activity has a feedback function for singing motor pattern generation. PMID:26334014

  7. DESIGN, FABRICATION, AND TESTING OF AN ADVANCED, NON-POLLUTING TURBINE DRIVE GAS GENERATOR

    SciTech Connect

    Unknown

    2002-01-31

    The objective of this report period was to continue the development of the Gas Generator design, fabrication and test of the non-polluting unique power turbine drive Gas Generator. Focus during this past report period has been to continue completion the Gas Generator design, completing the brazing and bonding experiments to determine the best method and materials necessary to fabricate the Gas Generator hardware, continuing to making preparations for fabricating and testing this Gas Generator and commencing with the fabrication of the Gas Generator hardware and ancillary hardware. Designs have been completed sufficiently such that Long Lead Items [LLI] have been ordered and upon arrival will be readied for the fabrication process. The keys to this design are the platelet construction of the injectors that precisely measures/meters the flow of the propellants and water all throughout the steam generating process and the CES patented gas generating cycle. The Igniter Assembly injector platelets fabrication process has been completed and bonded to the Igniter Assembly and final machined. The Igniter Assembly is in final assembly and is being readied for testing in the October 2001 time frame. Test Plan dated August 2001, was revised and finalized, replacing Test Plan dated May 2001.

  8. An Experimental Investigation of the Wave Pattern Generated by a Moving Pressure Source: Solitary Capillary-Gravity Waves

    NASA Astrophysics Data System (ADS)

    Duncan, J. H.; Diorio, J. D.; Lisiewski, A.; Harris, R.

    2009-11-01

    The wave pattern generated by a small pressure source moving across a water surface at speeds less than the minimum phase speed for linear gravity-capillary waves (cmin = 23 cm/s) was investigated experimentally. The resulting wave pattern was measured using cinematic shadowgraph and laser-induced fluorescence (LIF) techniques. The results show the existence of several distinct behavioral states. At low speeds, no wave behavior is observed and the pattern resembles the symmetric stationary condition. However, at a critical speed, but still below cmin, the pattern undergoes a sudden transition to an asymmetric state with a stationary, 2D solitary wave that forms behind the pressure source. This solitary wave is elongated in the cross-stream relative to the stream-wise direction and resembles gravity-capillary ``lumps'' observed in previous numerical calculations. As the translation speed approaches cmin, another time-dependent behavior is observed characterized by periodic ``shedding'' from a V-shaped solitary wave pattern. This work will be discussed in conjunction with the recent numerical calculations of T. Akylas and his research group.

  9. Genetic testing behavior and reporting patterns in electronic medical records for physicians trained in a primary care specialty or subspecialty

    PubMed Central

    Li, Cheng; Lester, William T

    2012-01-01

    Objective To characterize important patterns of genetic testing behavior and reporting in modern electronic medical records (EMRs) at the institutional level. Materials and methods Retrospective observational study using EMR data of all 10?715 patients who received genetic testing by physicians trained in a primary care specialty or subspecialty at an academic medical center between January 1, 2008 and December 31, 2010. Results Patients had a mean±SD age of 38.3±15.8?years (median 36.1, IQR 30.0–43.8). The proportion of female subjects in the study population was larger than in the general patient population (77.2% vs 55.0%, p<0.001) and they were younger than the male subjects in the study (36.5±13.2 vs 44.6±21.2?years, p<0.001). Approximately 1.1% of all patients received genetic testing. There were 942 physicians who ordered a total of 15?320 genetic tests. By volume, commonly tested genes involved mutations for cystic fibrosis (36.7%), prothrombin (13.7%), Tay–Sachs disease (6.7%), hereditary hemochromatosis (4.4%), and chronic myelogenous leukemia (4.1%). EMRs stored reports as free text with categorical descriptions of mutations and an average length of 269.4±153.2 words (median 242, IQR 146–401). Conclusions In this study, genetic tests were often ordered by a diverse group of physicians for women of childbearing age being evaluated for diseases that may affect potential offspring. EMRs currently serve primarily as a storage warehouse for textual reports that could potentially be transformed into meaningful structured data for next-generation clinical decision support. Further studies are needed to address the design, development, and implementation of EMRs capable of managing the critical genetic health information challenges of the future. PMID:22511017

  10. Patterning of affective responses during a graded exercise test in children and adolescents.

    PubMed

    Benjamin, Charlotte C; Rowlands, Alex; Parfitt, Gaynor

    2012-05-01

    Past studies have shown the patterning of affective responses during a graded exercise test (GXT) in adult and male adolescent populations, but none have explored the patterns in adolescent girls or younger children. This study explored the patterning of affective responses during a GXT in adolescents and younger children. Forty-nine children (21 male and 28 female) aged between 8-14 years (10.8 ± 1.8 years) completed a GXT. Ventilatory threshold (VT) was identified. At the end of each incremental step, participants reported affective valence. Results revealed that affective valence assessed by the Feeling Scale (FS) significantly declined from the onset of exercise until the point of VT in the younger children, but remained relatively stable in the adolescents. Exercise above the VT brought about significant declines in affective valence regardless of age or sex, but the decrease was significantly greater in adolescents. Results suggest it may be preferable to prescribe lower exercise intensities (below VT) for children, compared with adolescents, to ensure a positive affective response. PMID:22728418

  11. Generating custom test plans for CASE{sup *}Dictionary 5.0

    SciTech Connect

    Atkins, K.D.

    1994-04-01

    Most database development organizations use a formal software development methodology that requires a certain amount of formal testing. The amount of formal testing that will be performed will vary from methodology to methodology and from site to site. If a very detailed formal test plan is required for each module in a system, the work involved to produce the test plan can be tedious and costly. After a system has been designed and developed using Oracle*CASE, there is much useful information in the CASE*Dictionary repository. If this information could be tied to specific test requirements, a test plan could be generated automatically, saving much time and resources. This paper shows how CASE*Dictionary can be used to store test plan information that can then be used to generate a specific test plan for each module based on it`s detailed data usage.

  12. Learning Outcome Testing Program: Standardized Classroom Testing in West Virginia through Item Banking, Test Generation, and Curricular Management Software.

    ERIC Educational Resources Information Center

    Willis, John A.

    1990-01-01

    The Learning Outcome Testing Program of the West Virginia Department of Education is designed to provide public school teachers/administrators with test questions matching learning outcomes. The approach, software selection, results of pilot tests with teachers in 13 sites, and development of test items for item banks are described. (SLD)

  13. Vibration Testing of the Pluto/New Horizons Radioisotope Thermoelectric Generator

    SciTech Connect

    Charles D. Griffin

    2006-06-01

    The Radioisotopic Thermal Generator (RTG) for the Pluto/New Horizons spacecraft was subjected to a flight dynamic acceptance test to demonstrate that it would perform successfully following launch. Seven RTGs of this type had been assembled and tested at Mound, Ohio from 1984 to 1997. This paper chronicles major events in establishing a new vibration test laboratory at the Idaho National Laboratory and the nineteen days of dynamic testing.

  14. Large-Scale Multiobjective Static Test Generation for Web-Based Testing with Integer Programming

    ERIC Educational Resources Information Center

    Nguyen, M. L.; Hui, Siu Cheung; Fong, A. C. M.

    2013-01-01

    Web-based testing has become a ubiquitous self-assessment method for online learning. One useful feature that is missing from today's web-based testing systems is the reliable capability to fulfill different assessment requirements of students based on a large-scale question data set. A promising approach for supporting large-scale web-based…

  15. Large-Scale Multiobjective Static Test Generation for Web-Based Testing with Integer Programming

    ERIC Educational Resources Information Center

    Nguyen, M. L.; Hui, Siu Cheung; Fong, A. C. M.

    2013-01-01

    Web-based testing has become a ubiquitous self-assessment method for online learning. One useful feature that is missing from today's web-based testing systems is the reliable capability to fulfill different assessment requirements of students based on a large-scale question data set. A promising approach for supporting large-scale web-based…

  16. Use of chaotic and random vibrations to generate high frequency test inputs

    SciTech Connect

    Gregory, D. L.; Paez, T. L.

    1990-01-01

    This paper and a companion paper show the traditional limits on amplitude and frequency that can be generated in a laboratory test on a vibration exciter can be substantially extended. This is accomplished by attaching a device to the shaker that permits controlled metal to metal impacts that generate high frequency, high acceleration environment on a test surface. A companion paper (Reference 1) shows that a sinusoidal or random shaker input can be used to generate a random vibration environment on the test surface. This paper derives the three response components that occur on the test surface due to an impact on the bottom surface and the base driven response from the shaker input. These response components are used to generate impulse response functions and frequency response functions which are used in the companion paper to derive power spectral density functions for the overall response. 9 refs., 8 figs.

  17. Testing of the Advanced Stirling Radioisotope Generator Engineering Unit at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.

    2013-01-01

    The Advanced Stirling Radioisotope Generator (ASRG) is a high-efficiency generator being developed for potential use on a Discovery 12 space mission. Lockheed Martin designed and fabricated the ASRG Engineering Unit (EU) under contract to the Department of Energy. This unit was delivered to NASA Glenn Research Center in 2008 and has been undergoing extended operation testing to generate long-term performance data for an integrated system. It has also been used for tests to characterize generator operation while varying control parameters and system inputs, both when controlled with an alternating current (AC) bus and with a digital controller. The ASRG EU currently has over 27,000 hours of operation. This paper summarizes all of the tests that have been conducted on the ASRG EU over the past 3 years and provides an overview of the test results and what was learned.

  18. Standard test case runs for the empulse monopole fieldsolver and conductivity generation model

    SciTech Connect

    Chambers, F.W.; Cox, D.M.

    1981-03-02

    The physical models for the conductivity generation and fieldsolver used in several LLNL beam propagation codes are presented. A generalized beam profile is presented and four standard test cases are proposed.

  19. Non-contact acoustic tests based on nanosecond laser ablation: Generation of a pulse sound source with a small amplitude

    NASA Astrophysics Data System (ADS)

    Hosoya, Naoki; Kajiwara, Itsuro; Inoue, Tatsuo; Umenai, Koh

    2014-09-01

    A method to generate a pulse sound source for acoustic tests based on nanosecond laser ablation with a plasma plume is discussed. Irradiating a solid surface with a laser beam expands a high-temperature plasma plume composed of free electrons, ionized atoms, etc. at a high velocity throughout ambient air. The shockwave generated by the plasma plume becomes the pulse sound source. A laser ablation sound source has two features. Because laser ablation is induced when the laser fluence reaches 1012-1014 W/m2, which is less than that for laser-induced breakdown (1015 W/m2), laser ablation can generate a lower sound pressure, and the sound source has a hemispherical radiation pattern on the surface where laser ablation is generated. Additionally, another feature is that laser-induced breakdown sound sources can fluctuate, whereas laser ablation sound sources do not because laser ablation is produced at a laser beam-irradiation point. We validate this laser ablation method for acoustic tests by comparing the measured and theoretical resonant frequencies of an impedance tube.

  20. Optimization of Gas Generation Testing of Contact-Handled Transuranic Solidified

    SciTech Connect

    Tamara Shokes; Kevin J. Liekhus; Vivian Bowman; Eric Schweinsberg

    2006-05-18

    The Contact-Handled Transuranic Waste Authorized methods for Payload Control (CH-TRAMPAC) requires that drums containing Waste Type IV (solidified organic waste) must be evaluated by gas generation testing (GGT) because a G-value, a measure of gas generation potential, has not been determined for Waste Type IV.

  1. The Next Generation of Users: Prevalence and Longitudinal Patterns of Tobacco Use Among US Young Adults

    PubMed Central

    Williams, Valerie; Rath, Jessica; Villanti, Andrea C.; Vallone, Donna

    2014-01-01

    Objectives. We monitored the prevalence and patterns of use of the array of tobacco products available to young adults, who are at risk for initiation and progression to established tobacco use. Methods. We used data from waves 1 to 3 of GfK’s KnowledgePanel (2011–2012), a nationally representative cohort of young adults aged 18 to 34 years (n = 2144). We examined prevalence and patterns of tobacco product use over time, associated demographics, and state-level tobacco policy. We used multivariable logistic regression to determine predictors of initiation of cigarettes as well as noncombustible and other combustible products. Results. The prevalence of ever tobacco use rose from 57.28% at wave 1 to 67.43% at wave 3. Use of multiple products was the most common pattern (66.39% of tobacco users by wave 3). Predictors of initiation differed by product type and included age, race/ethnicity, policy, and use of other tobacco products. Conclusions. Tobacco use is high among young adults and many are using multiple products. Efforts to implement policy and educate young adults about the risks associated with new and emerging products are critical to prevent increased initiation of tobacco use. PMID:24922152

  2. Programming Surface Energy Driven Marangoni Convection in Polymer Thin Films to Generate Topographic Patterns

    NASA Astrophysics Data System (ADS)

    Kim, Chae Bin; Janes, Dustin; Arshad, Talha; Katzenstein, Joshua; Prisco, Nathan; McGuffin, Dana; Bonnecaze, Roger; Ellison, Christopher

    2015-03-01

    The Marangoni effect describes how fluid flows in response to gradients in surface energy. We recently developed a method for photochemically preprograming spatial surface energy patterns in glassy polystyrene (PS) thin films. UV irradiation through a mask selectively dehydrogenates the PS, thus increasing surface energy in the UV exposed regions compared to the unexposed regions. After heating the film to the liquid state, transport of polymer occurs from regions of low surface energy to regions of high surface energy. This method can be harnessed to rapidly manufacture polymer films possessing prescribed three-dimensional topographies reflective of the original light exposure pattern. To quantify and verify this phenomenon, a theoretical model that gives a more thorough understanding of the physics of this process, its limits and ways to apply it efficiently for various target metrics will also be presented along with comparisons between theoretical predictions and experimental observations. Finally, while PS dehydrogenation can be used to produce a variety of topographical patterns, judicious selection of the photosensitizing compounds in an otherwise transparent polymer expands the use of this method to more readily available light sources.

  3. Design of a Facility to Test the Advanced Stirling Radioisotope Generator Engineering Unit

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Schreiber, Jeffrey G.; Oriti, Salvatore M.; Meer, David W.; Brace, Michael H.; Dugala, Gina

    2009-01-01

    The Advanced Stirling Radioisotope Generator (ASRG) is being considered to power deep space missions. An engineering unit, the ASRG-EU, was designed and fabricated by Lockheed Martin under contract to the Department of Energy. This unit is currently on an extended operation test at NASA Glenn Research Center to generate performance data and validate the life and reliability predictions for the generator and the Stirling convertors. A special test facility was designed and built for testing the ASRG-EU. Details of the test facility design are discussed. The facility can operate the convertors under AC bus control or with the ASRG-EU controller. It can regulate input thermal power in either a fixed temperature or fixed power mode. An enclosure circulates cooled air around the ASRG-EU to remove heat rejected from the ASRG-EU by convection. A custom monitoring and data acquisition system supports the test. Various safety features, which allow 2417 unattended operation, are discussed.

  4. Terahertz wave generation in orientation-patterned GaAs using resonantly enhanced schemes

    NASA Astrophysics Data System (ADS)

    Vodopyanov, K. L.; Schaar, J. E.; Kuo, P. S.; Fejer, M. M.; Yu, X.; Harris, J. S.; Kozlov, V. G.; Bliss, D.; Lynch, C.

    2007-02-01

    Zincblende semiconductors (GaAs, GaP) show great potential for quasi-phase-matched (QPM) THz generation because of their small (20 times less than in lithium niobate) absorption coefficient at terahertz frequencies, small mismatch between the optical group and THz phase velocities, high thermal conductivity, and decent electro-optical coefficient. Terahertz-wave generation was demonstrated recently in QPM GaAs, using optical rectification of femtosecond pulses. Here we report on a new efficient widely tunable (0.5-3.5 THz) source of THz radiation based on quasi-phase-matched GaAs crystal. The source is based on difference frequency generation inside the cavity of a synchronously pumped near-degenerate picosecond OPO and takes advantage of resonantly enhanced both the signal and the idler waves. THz average power as high as 1 mW was achieved in a compact setup.

  5. Automating test case generation for coverages required by FAA standard DO-178B

    NASA Technical Reports Server (NTRS)

    Voas, Jeffrey M.; Payne, Jeffery E.; Miller, Keith W.

    1993-01-01

    Coverage testing techniques are required by the FAA for various levels of subsystem criticality at the unit testing level. Higher levels of criticality require coverage schemes that frequently require more and more test cases, particularly when the number of conditions in a decision grows. For example, if we have a decision with n conditions of the form: if (/ci/ or /c2/ or .... or /cn/) then there are 2(n) possible combinations of condition outcomes. Given the enormous number of inputs that may be required to satisfy different coverages, and given that there are no automated tools for determining these inputs (to our knowledge), we will show how one alternative testing technique, mutation testing, can be coerced into generating inputs that satisfy a code coverage scheme X, i.e., if we modify the rules for mutant generation during mutation testing, this technique will provide test cases that satisfy X.

  6. 40 CFR 53.42 - Generation of test atmospheres for wind tunnel tests.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... sufficiently large cross-sectional area such that the test sampler, or portion thereof, as installed in the.... An array of not less than five evenly spaced isokinetic samplers shall be used to determine...

  7. 40 CFR 53.42 - Generation of test atmospheres for wind tunnel tests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... sufficiently large cross-sectional area such that the test sampler, or portion thereof, as installed in the.... An array of not less than five evenly spaced isokinetic samplers shall be used to determine...

  8. 40 CFR 53.42 - Generation of test atmospheres for wind tunnel tests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sufficiently large cross-sectional area such that the test sampler, or portion thereof, as installed in the.... An array of not less than five evenly spaced isokinetic samplers shall be used to determine...

  9. 40 CFR 53.42 - Generation of test atmospheres for wind tunnel tests.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... sufficiently large cross-sectional area such that the test sampler, or portion thereof, as installed in the.... An array of not less than five evenly spaced isokinetic samplers shall be used to determine...

  10. 40 CFR 53.42 - Generation of test atmospheres for wind tunnel tests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... sufficiently large cross-sectional area such that the test sampler, or portion thereof, as installed in the.... An array of not less than five evenly spaced isokinetic samplers shall be used to determine...

  11. Experience with ac hipot and partial discharge tests for commissioning generating station cables and switchgear

    SciTech Connect

    Gillespie, M.T.G.; Munchie, G.B.; Stone, G.C. )

    1989-09-01

    Increased reliability of 5 and 15 kV switchgear and cables in new generating stations can be achieved by commissioning such equipment with an ac hipot and partial discharge test, rather than with conventional dc tests. AC testing is much more sensitive than dc testing to flaws that will eventually result in equipment failure, especially for extruded polymeric cable. Since 1983, Ontario Hydro has been using a resonant ac power supply together with a commercial partial discharge detector to make ac testing of generating station service components practical and economical for the first time. To date, a total of 97 cable circuits and 60 metal-clad assemblies have been tested. The failure rate on testing of cable circuits was about 10% and for switchgear assemblies 32%. Most of the problems which resulted in ac test failures would not have been detected by the dc tests. This ac test equipment has also been used in existing stations for periodic maintenance tests to prove the reliability of cables, potheads, switchgear, motors and generators.

  12. Automated Learning of Subcellular Variation among Punctate Protein Patterns and a Generative Model of Their Relation to Microtubules

    PubMed Central

    Johnson, Gregory R.; Li, Jieyue; Shariff, Aabid; Rohde, Gustavo K.; Murphy, Robert F.

    2015-01-01

    Characterizing the spatial distribution of proteins directly from microscopy images is a difficult problem with numerous applications in cell biology (e.g. identifying motor-related proteins) and clinical research (e.g. identification of cancer biomarkers). Here we describe the design of a system that provides automated analysis of punctate protein patterns in microscope images, including quantification of their relationships to microtubules. We constructed the system using confocal immunofluorescence microscopy images from the Human Protein Atlas project for 11 punctate proteins in three cultured cell lines. These proteins have previously been characterized as being primarily located in punctate structures, but their images had all been annotated by visual examination as being simply “vesicular”. We were able to show that these patterns could be distinguished from each other with high accuracy, and we were able to assign to one of these subclasses hundreds of proteins whose subcellular localization had not previously been well defined. In addition to providing these novel annotations, we built a generative approach to modeling of punctate distributions that captures the essential characteristics of the distinct patterns. Such models are expected to be valuable for representing and summarizing each pattern and for constructing systems biology simulations of cell behaviors. PMID:26624011

  13. Automated Learning of Subcellular Variation among Punctate Protein Patterns and a Generative Model of Their Relation to Microtubules.

    PubMed

    Johnson, Gregory R; Li, Jieyue; Shariff, Aabid; Rohde, Gustavo K; Murphy, Robert F

    2015-12-01

    Characterizing the spatial distribution of proteins directly from microscopy images is a difficult problem with numerous applications in cell biology (e.g. identifying motor-related proteins) and clinical research (e.g. identification of cancer biomarkers). Here we describe the design of a system that provides automated analysis of punctate protein patterns in microscope images, including quantification of their relationships to microtubules. We constructed the system using confocal immunofluorescence microscopy images from the Human Protein Atlas project for 11 punctate proteins in three cultured cell lines. These proteins have previously been characterized as being primarily located in punctate structures, but their images had all been annotated by visual examination as being simply "vesicular". We were able to show that these patterns could be distinguished from each other with high accuracy, and we were able to assign to one of these subclasses hundreds of proteins whose subcellular localization had not previously been well defined. In addition to providing these novel annotations, we built a generative approach to modeling of punctate distributions that captures the essential characteristics of the distinct patterns. Such models are expected to be valuable for representing and summarizing each pattern and for constructing systems biology simulations of cell behaviors. PMID:26624011

  14. Consumption patterns and household hazardous solid waste generation in an urban settlement in Mexico

    SciTech Connect

    Delgado Otoniel, Buenrostro

    2008-07-01

    Mexico is currently facing a crisis in the waste management field. Some efforts have just commenced in urban and in rural settlements, e.g., conversion of open dumps into landfills, a relatively small composting culture, and implementation of source separation and plastic recycling strategies. Nonetheless, the high heterogeneity of components in the waste, many of these with hazardous properties, present the municipal collection services with serious problems, due to the risks to the health of the workers and to the impacts to the environment as a result of the inadequate disposition of these wastes. A generation study in the domestic sector was undertaken with the aim of finding out the composition and the generation rate of household hazardous waste (HHW) produced at residences. Simultaneously to the generation study, a socioeconomic survey was applied to determine the influence of income level on the production of HHW. Results from the solid waste generation analysis indicated that approximately 1.6% of the waste stream consists of HHW. Correspondingly, it was estimated that in Morelia, a total amount of 442 ton/day of domestic waste are produced, including 7.1 ton of HHW per day. Furthermore, the overall amount of HHW is not directly related to income level, although particular byproducts do correlate. However, an important difference was observed, as the brands and the presentation sizes of goods and products used in each socioeconomic stratum varied.

  15. Class and University Education: Inter-Generational Patterns in Canada. NALL Working Paper.

    ERIC Educational Resources Information Center

    Livingstone, D. W.; Stowe, Susan

    Young people from lower class origins continue to face major barriers to university education in Canada. This paper documents both substantial inter-generational class mobility and continuing inequalities in formal educational attainments by class origins. While Canada now has the world's higher educational attainments in its youth cohort and has…

  16. Optical generation of a circular harmonic filter for rotation and translation invariant optical pattern recognition

    NASA Technical Reports Server (NTRS)

    Cheng, Yeou-Yen

    1987-01-01

    A new method to generate a circular harmonic filter with both rotation and translation invariance is described, which is based on a phase-shifted double-exposure (PSDE) technique. An expression for the peak correlation intensity at the origin for the correlation plane as a function of target orientation for the PSDE filter is derived. Experimental results confirming the theoretical predictions are provided.

  17. Age-dependent pattern of connexin43 expression in testes of European bison (Bison bonasus, L.).

    PubMed

    Hejmej, Anna; Kopera, Ilona; Kotula-Balak, Malgorzata; Gizejewski, Zygmunt; Bili?ska, Barbara

    2009-11-01

    Morphology and the expression of connexin43 (Cx43) was investigated in testes of immature, prepubertal, and adult European bison bulls by means of routine histology, immunohistochemistry, and Western blotting, respectively. Testes were collected from culled animals living in Bialowieza and Borecka Forests, Poland. Histological examination of testicular tissue of immature and prepubertal males revealed normal structure, whereas of adult individuals either normal testicular structure with advanced spermatogenesis or varying degrees of tubule and interstitial tissue abnormality were seen. Immunohistochemical studies revealed Cx43 signal mostly at Leydig cell membrane appositions. In testes of immature males heterogeneous staining was observed; its intensity markedly increased in prepubertal males reaching almost two times more intense staining in adults. Strong Cx43 signal between Leydig cells was also observed in testes with structural alterations; however, sporadically it was of weak linear pattern. In the tubules of the latter, the intensity of Cx43 staining was weak to moderate or it was even absent. Immunohistochemical qualitative analysis was confirmed by quantitative image analysis in which the staining intensity was expressed as relative optical density of diaminobenzidine deposits. Data from Western blot analyses confirmed the results obtained by immunohistochemistry; immunodetectable Cx43 protein as a band of 43 kDa was detected in all testes samples. Overall, the increase in Cx43 level in testes along the bison postnatal development may be capable of a better exchange of metabolites and coordinating Leydig cell activity during maturation. A relationship between homozygosity occurring in European bison and altered intercellular communication is suggested. PMID:19623571

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

    ERIC Educational Resources Information Center

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

    2015-01-01

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

  19. Description and test results of a variable speed, constant frequency generating system

    NASA Astrophysics Data System (ADS)

    Brady, F. J.

    1985-12-01

    The variable-speed, constant frequency generating system developed for the Mod-0 wind turbine is presented. This report describes the system as it existed at the conclusion of the project. The cycloconverter control circuit is described including the addition of field-oriented control. The laboratory test and actual wind turbine test results are included.

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

    ERIC Educational Resources Information Center

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

    2015-01-01

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

  1. Design, fabrication, test qualification and price analysis of a third generation solar cell module

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The design, fabrication, test, and qualification of a third generation intermediate load solar cell module are presented. A technical discussion of the detailed module design, preliminary design review, design modifications, and environmental testing are included. A standardized pricing system is utilized to establish the cost competitiveness of this module design.

  2. Performance of small CST column gas generation test in radiation field

    SciTech Connect

    Jacobs, R.A.; Rueter, K.J.; Carter, J.T.

    2000-02-02

    The purpose of this position paper is to describe the circumstances leading to the decision to delete the dynamic CST small column radiolytic gas generation test from the current phase of tests and the impact of that decision on the Decision Phase.

  3. 78 FR 38411 - Vogtle Electric Generating Plant, Unit 4; Inspections, Tests, Analyses, and Acceptance Criteria

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-26

    ...The U.S. Nuclear Regulatory Commission (NRC) staff has determined that the inspections, tests, and analyses have been successfully completed, and that the specified acceptance criteria are met for Inspections, Tests, Analyses, and Acceptance Criteria (ITAAC) E.2.5.04.05.05.01, for the Vogtle Electric Generating Plant, Unit...

  4. Wind Turbine Generator System Safety and Function Test Report for the Ventera VT10 Wind Turbine

    SciTech Connect

    Smith, J.; Huskey, A.; Jager, D.; Hur, J.

    2012-11-01

    This report summarizes the results of a safety and function test that NREL conducted on the Ventera VT10 wind turbine. This test was conducted in accordance with the International Electrotechnical Commissions' (IEC) standard, Wind Turbine Generator System Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed.2.0, 2006-03.

  5. Wind Turbine Generator System Safety and Function Test Report for the Entegrity EW50 Wind Turbine

    SciTech Connect

    Smith, J.; Huskey, A.; Jager, D.; Hur, J.

    2012-11-01

    This report summarizes the results of a safety and function test that NREL conducted on the Entegrity EW50 wind turbine. This test was conducted in accordance with the International Electrotechnical Commissions' (IEC) standard, Wind Turbine Generator System Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed.2.0, 2006-03.

  6. Leak injection/detection input for B and W prototype steam generator test request

    SciTech Connect

    1980-11-18

    The goal of the leak injection/detection phase of the test program on the prototype steam generator is to obtain data that can be used to specify the leak protection system for the plant unit steam generators. Both chemical and two acoustic leak detection methods (by GE and Rockwell International) are to be considered. The chemical system has been selected as the reference based on its more developed state. The acoustic methods have potential both as small leak detection systems and as intermediate leak protection/automatic shutdown systems. Simulated leak injections will be made at various locations within the steam generator to determine the performance of the chemical system as specifically applied to the B and W helical coil steam generator geometry. Acoustic tests will be made to characterize the various steam generator background noise sources and to record acoustic signals during smulated leak injections, in order to predict the performance of both systems.

  7. SRG110 Stirling Generator Dynamic Simulator Vibration Test Results and Analysis Correlation

    NASA Technical Reports Server (NTRS)

    Suarez, Vicente J.; Lewandowski, Edward J.; Callahan, John

    2006-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin (LM), and NASA Glenn Research Center (GRC) have been developing the Stirling Radioisotope Generator (SRG110) for use as a power system for space science missions. The launch environment enveloping potential missions results in a random input spectrum that is significantly higher than historical RPS launch levels and is a challenge for designers. Analysis presented in prior work predicted that tailoring the compliance at the generator-spacecraft interface reduced the dynamic response of the system thereby allowing higher launch load input levels and expanding the range of potential generator missions. To confirm analytical predictions, a dynamic simulator representing the generator structure, Stirling convertors and heat sources was designed and built for testing with and without a compliant interface. Finite element analysis was performed to guide the generator simulator and compliant interface design so that test modes and frequencies were representative of the SRG110 generator. This paper presents the dynamic simulator design, the test setup and methodology, test article modes and frequencies and dynamic responses, and post-test analysis results. With the compliant interface, component responses to an input environment exceeding the SRG110 qualification level spectrum were all within design allowables. Post-test analysis included finite element model tuning to match test frequencies and random response analysis using the test input spectrum. Analytical results were in good overall agreement with the test results and confirmed previous predictions that the SRG110 power system may be considered for a broad range of potential missions, including those with demanding launch environments.

  8. SRG110 Stirling Generator Dynamic Simulator Vibration Test Results and Analysis Correlation

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Suarez, Vicente J.; Goodnight, Thomas W.; Callahan, John

    2007-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin (LM), and NASA Glenn Research Center (GRC) have been developing the Stirling Radioisotope Generator (SRG110) for use as a power system for space science missions. The launch environment enveloping potential missions results in a random input spectrum that is significantly higher than historical radioisotope power system (RPS) launch levels and is a challenge for designers. Analysis presented in prior work predicted that tailoring the compliance at the generator-spacecraft interface reduced the dynamic response of the system thereby allowing higher launch load input levels and expanding the range of potential generator missions. To confirm analytical predictions, a dynamic simulator representing the generator structure, Stirling convertors and heat sources were designed and built for testing with and without a compliant interface. Finite element analysis was performed to guide the generator simulator and compliant interface design so that test modes and frequencies were representative of the SRG110 generator. This paper presents the dynamic simulator design, the test setup and methodology, test article modes and frequencies and dynamic responses, and post-test analysis results. With the compliant interface, component responses to an input environment exceeding the SRG110 qualification level spectrum were all within design allowables. Post-test analysis included finite element model tuning to match test frequencies and random response analysis using the test input spectrum. Analytical results were in good overall agreement with the test results and confirmed previous predictions that the SRG110 power system may be considered for a broad range of potential missions, including those with demanding launch environments.

  9. The generation of biomolecular patterns in highly porous collagen-GAG scaffolds using direct photolithography.

    PubMed

    Martin, Teresa A; Caliari, Steven R; Williford, Paul D; Harley, Brendan A; Bailey, Ryan C

    2011-06-01

    The extracellular matrix (ECM) is a complex organization of structural proteins found within tissues and organs. Heterogeneous tissues with spatially and temporally modulated properties play an important role in organism physiology. Here we present a benzophenone (BP) based direct, photolithographic approach to spatially pattern solution phase biomolecules within collagen-GAG (CG) scaffolds and demonstrate creation of a wide range of patterns composed of multiple biomolecular species in a manner independent from scaffold fabrication steps. We demonstrate the ability to immobilize biomolecules at surface densities of up to 1000 ligands per square micron on the scaffold strut surface and to depths limited by the penetration depth of the excitation source into the scaffold structure. Importantly, while BP photopatterning does further crosslink the CG scaffold, evidenced by increased mechanical properties and collagen crystallinity, it does not affect scaffold microstructural or compositional properties or negatively influence cell adhesion, viability, or proliferation. We show that covalently photoimmobilized fibronectin within a CG scaffold significantly increases the speed of MC3T3-E1 cell attachment relative to the bare CG scaffold or non-specifically adsorbed fibronectin, suggesting that this approach can be used to improve scaffold bioactivity. Our findings, on the whole, establish the use of direct, BP photolithography as a methodology for covalently incorporating activity-improving biochemical cues within 3D collagen biomaterial scaffolds with spatial control over biomolecular deposition. PMID:21397322

  10. Synaptic signal streams generated by ex vivo neuronal networks contain non-random, complex patterns.

    PubMed

    Lee, Sangmook; Zemianek, Jill M; Shultz, Abraham; Vo, Anh; Maron, Ben Y; Therrien, Mikaela; Courtright, Christina; Guaraldi, Mary; Yanco, Holly A; Shea, Thomas B

    2014-11-01

    Cultured embryonic neurons develop functional networks that transmit synaptic signals over multiple sequentially connected neurons as revealed by multi-electrode arrays (MEAs) embedded within the culture dish. Signal streams of ex vivo networks contain spikes and bursts of varying amplitude and duration. Despite the random interactions inherent in dissociated cultures, neurons are capable of establishing functional ex vivo networks that transmit signals among synaptically connected neurons, undergo developmental maturation, and respond to exogenous stimulation by alterations in signal patterns. These characteristics indicate that a considerable degree of organization is an inherent property of neurons. We demonstrate herein that (1) certain signal types occur more frequently than others, (2) the predominant signal types change during and following maturation, (3) signal predominance is dependent upon inhibitory activity, and (4) certain signals preferentially follow others in a non-reciprocal manner. These findings indicate that the elaboration of complex signal streams comprised of a non-random distribution of signal patterns is an emergent property of ex vivo neuronal networks. PMID:25172170

  11. The generation of biomolecular patterns in highly porous collagen-GAG scaffolds using direct photolithography

    PubMed Central

    Martin, Teresa A.; Caliari, Steven R.; Williford, Paul D.; Harley, Brendan A.; Bailey, Ryan C.

    2014-01-01

    The extracellular matrix (ECM) is a complex organization of structural proteins found within tissues and organs. Heterogeneous tissues with spatially and temporally modulated properties play an important role in organism physiology. Here we present a benzophenone (BP) based direct, photolithographic approach to spatially pattern solution phase biomolecules within collagen-GAG (CG) scaffolds and demonstrate creation of a wide range of patterns composed of multiple biomolecular species in a manner independent from scaffold fabrication steps. We demonstrate the ability to immobilize biomolecules at surface densities of up to 1000 ligands per square micron on the scaffold strut surface and to depths limited by the penetration depth of the excitation source into the scaffold structure. Importantly, while BP photopatterning does further crosslink the CG scaffold, evidenced by increased mechanical properties and collagen crystallinity, it does not affect scaffold microstructural or compositional properties or negatively influence cell adhesion, viability, or proliferation. We show that covalently photoimmobilized fibronectin within a CG scaffold significantly increases the speed of MC3T3-E1 cell attachment relative to the bare CG scaffold or non-specifically adsorbed fibronectin, suggesting that this approach can be used to improve scaffold bioactivity. Our findings, on the whole, establish the use of direct, BP photolithography as a methodology for covalently incorporating activity-improving biochemical cues within 3D collagen biomaterial scaffolds with spatial control over biomolecular deposition. PMID:21397322

  12. Certification testing of the Los Alamos National Laboratory Heat Source/Radioisotopic Thermoelectric Generator shipping container

    SciTech Connect

    Bronowski, D.R.; Madsen, M.M.

    1991-09-01

    The Heat Source/Radioisotopic Thermoelectric Generator shipping counter is a Type B packaging currently under development by Los Alamos National Laboratory. Type B packaging for transporting radioactive material is required to maintain containment and shielding after being exposed to normal and hypothetical accident environments defined in Title 10 of the Code of Federal Regulations Part 71. A combination of testing and analysis is used to verify the adequacy of this packaging design. This report documents the testing portion of the design verification. Six tests were conducted on a prototype package: a water spray test, a 4-foot normal conditions drop test, a 30-foot drop test, a 40-inch puncture test, a 30-minute thermal test, and an 8-hour immersion test.

  13. Test-Case Generation using an Explicit State Model Checker Final Report

    NASA Technical Reports Server (NTRS)

    Heimdahl, Mats P. E.; Gao, Jimin

    2003-01-01

    In the project 'Test-Case Generation using an Explicit State Model Checker' we have extended an existing tools infrastructure for formal modeling to export Java code so that we can use the NASA Ames tool Java Pathfinder (JPF) for test case generation. We have completed a translator from our source language RSML(exp -e) to Java and conducted initial studies of how JPF can be used as a testing tool. In this final report, we provide a detailed description of the translation approach as implemented in our tools.

  14. Simple Process-Based Simulators for Generating Spatial Patterns of Habitat Loss and Fragmentation: A Review and Introduction to the G-RaFFe Model

    PubMed Central

    Pe'er, Guy; Zurita, Gustavo A.; Schober, Lucia; Bellocq, Maria I.; Strer, Maximilian; Müller, Michael; Pütz, Sandro

    2013-01-01

    Landscape simulators are widely applied in landscape ecology for generating landscape patterns. These models can be divided into two categories: pattern-based models that generate spatial patterns irrespective of the processes that shape them, and process-based models that attempt to generate patterns based on the processes that shape them. The latter often tend toward complexity in an attempt to obtain high predictive precision, but are rarely used for generic or theoretical purposes. Here we show that a simple process-based simulator can generate a variety of spatial patterns including realistic ones, typifying landscapes fragmented by anthropogenic activities. The model “G-RaFFe” generates roads and fields to reproduce the processes in which forests are converted into arable lands. For a selected level of habitat cover, three factors dominate its outcomes: the number of roads (accessibility), maximum field size (accounting for land ownership patterns), and maximum field disconnection (which enables field to be detached from roads). We compared the performance of G-RaFFe to three other models: Simmap (neutral model), Qrule (fractal-based) and Dinamica EGO (with 4 model versions differing in complexity). A PCA-based analysis indicated G-RaFFe and Dinamica version 4 (most complex) to perform best in matching realistic spatial patterns, but an alternative analysis which considers model variability identified G-RaFFe and Qrule as performing best. We also found model performance to be affected by habitat cover and the actual land-uses, the latter reflecting on land ownership patterns. We suggest that simple process-based generators such as G-RaFFe can be used to generate spatial patterns as templates for theoretical analyses, as well as for gaining better understanding of the relation between spatial processes and patterns. We suggest caution in applying neutral or fractal-based approaches, since spatial patterns that typify anthropogenic landscapes are often non-fractal in nature. PMID:23724108

  15. [Next generation sequencing and its applications in non-invasive prenatal testing of aneuploidies].

    PubMed

    Babay, Lilla Éva; Horányi, Dániel; Rigó, János; Nagy, Gyula Richárd

    2015-06-28

    The development of the new generation sequencing techniques brought a new era in the field of DNA sequencing, that also revolutionized the prenatal screening for aneuploidy. In order to provide a more complete view, the authors describe some first generation methods as well as the theoretical and technical background of the next generation methods. In the second part of this review, the authors focuse on non-invasive prenatal testing, which is a fetal cell-free DNA based method requiring advanced sequencing procedures. After discussing the theoretical and technical background, the authors review current application and utility of non-invasive prenatal testing. They conclude that non-invasive prenatal testing is the most effective screening test in high risk pregnancies and its efficiency can be justified in studies involving low risk pregnancies as well. PMID:26104666

  16. Digital test signal generation: An accurate SNR calibration approach for the DSN

    NASA Technical Reports Server (NTRS)

    Gutierrez-Luaces, B. O.

    1991-01-01

    A new method of generating analog test signals with accurate signal to noise ratios (SNRs) is described. High accuracy will be obtained by simultaneous generation of digital noise and signal spectra at a given baseband or bandpass limited bandwidth. The digital synthesis will provide a test signal embedded in noise with the statistical properties of a stationary random process. Accuracy will only be dependent on test integration time with a limit imposed by the system quantization noise (expected to be 0.02 dB). Setability will be approximately 0.1 dB. The first digital SNR generator to provide baseband test signals is being built and will be available in early 1991.

  17. DESIGN, FABRICATION, AND TESTING OF AN ADVANCED, NON-POLLUTING TURBINE DRIVE GAS GENERATOR

    SciTech Connect

    Stephen E. Doyle

    2002-12-31

    The objectives of this report period were to continue and complete testing of the Gas Generator hardware, to complete and submit a Draft Final Report, and after incorporation of adjustments required, to then submit the Final Report. Focus during this report period was initially on testing the Gas Generator. While conducting scheduled full power tests of the Gas Generator at the facilities of the testing sub-contractor, National Testing Services [NTS], in Santa Clarita CA, anomalies in the performance of the Gas Generator were discovered. All testing was stopped on November 6, 2002. An expert team was formed to evaluate the anomalies and to recommend any appropriate corrective actions. After extensive analyses of the actual hardware, the test data acquired and recorded during testing, and a review of the test facilities and procedures, the Anomalies Review Team recommended that CES modify the combustion chamber front end cooling method and modify the configuration of the diluent injectors downstream of the combustion chamber, to eliminate the anomalies. At a review meeting convened in Sacramento CA on November 23, 2002, outside experts from the Lawrence Livermore National Laboratory, Air Liquide's Research Center in Chicago IL, and the California Energy Commission, confirmed that the expert team's assessed cause of the problem was the likely cause, and the recommended corrective actions were appropriate. Modified hardware drawings were produced in late November-early December 2002, hardware fabrication was begun in December, and was in process at the end of December. Also during December, the NTS test facility was being adjusted to take account of the modified hardware configuration being produced. All work was aimed toward realizing a schedule of resumed testing by mid-January for completion of tests by end of January or early February, 2003. Original objectives of the program remain in place and approximately ninety (90) percent of those objectives had been completed prior to discovery of the anomalies. The accomplished objectives to date are described in this report.

  18. Second-Harmonic-Generation Microscopy Using Excitation Beam with Controlled Polarization Pattern to Determine Three-Dimensional Molecular Orientation

    NASA Astrophysics Data System (ADS)

    Yoshiki, Keisuke; Hashimoto, Mamoru; Araki, Tsutomu

    2005-08-01

    We have developed a second-harmonic-generation (SHG) microscope using an excitation beam with a controlled polarization pattern in order to detect three-dimensional molecular orientation. The electric field at the focus is controlled three-dimensionally by modifying the polarization distribution with a parallel-aligned nematic-liquid-crystal spatial-light-modulator without any mechanical moving parts. We demonstrated that the SHG signal from an Achilles tendon, sliced so that collagen fibers were aligned parallel to the optical axis, excited by a radially polarized beam was higher than those excited by linearly polarized beams. The possibility of determinating three-dimensional molecular orientation was thus shown.

  19. Elucidating the role of topological pattern discovery and support vector machine in generating predictive models for Indian summer monsoon rainfall

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Manojit; Chattopadhyay, Surajit

    2015-07-01

    The present paper reports a study, where growing hierarchical self-organising map (GHSOM) has been applied to achieve a visual cluster analysis to the Indian rainfall dataset consisting of 142 years of Indian rainfall data so that the yearly rainfall can be segregated into small groups to visualise the pattern of clustering behaviour of yearly rainfall due to changes in monthly rainfall for each year. Also, through support vector machine (SVM), it has been observed that generation of clusters impacts positively on the prediction of the Indian summer monsoon rainfall. Results have been presented through statistical and graphical analyses.

  20. Clinical features of congenital adrenal insufficiency including growth patterns and significance of ACTH stimulation test.

    PubMed

    Koh, Ji Won; Kim, Gu Hwan; Yoo, Han Wook; Yu, Jeesuk

    2013-11-01

    Congenital adrenal insufficiency is caused by specific genetic mutations. Early suspicion and definite diagnosis are crucial because the disease can precipitate a life-threatening hypovolemic shock without prompt treatment. This study was designed to understand the clinical manifestations including growth patterns and to find the usefulness of ACTH stimulation test. Sixteen patients with confirmed genotyping were subdivided into three groups according to the genetic study results: congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH, n=11), congenital lipoid adrenal hyperplasia (n=3) and X-linked adrenal hypoplasia congenita (n=2). Bone age advancement was prominent in patients with CAH especially after 60 months of chronologic age (n=6, 67%). They were diagnosed in older ages in group with bone age advancement (P<0.05). Comorbid conditions such as obesity, mental retardation, and central precocious puberty were also prominent in this group. In conclusion, this study showed the importance of understanding the clinical symptoms as well as genetic analysis for early diagnosis and management of congenital adrenal insufficiency. ACTH stimulation test played an important role to support the diagnosis and serum 17-hydroxyprogesterone levels were significantly elevated in all of the CAH patients. The test will be important for monitoring growth and puberty during follow up of patients with congenital adrenal insufficiency. PMID:24265530

  1. Radioisotope Thermoelectric Generator Package O-Ring Seal Material Validation Testing

    SciTech Connect

    Adkins, H.E.; Ferrell, P.C.; Knight, R.C.

    1994-09-30

    The Radioisotope Thermoelectric Generator Package O-Ring Seal Material Validation Test was conducted to validate the use of the Butyl material as a primary seal throughout the required temperature range. Three tests were performed at (1) 233 K ({minus}40 {degrees}F), (2) a specified operating temperature, and (3) 244 K ({minus}20 {degrees}F) before returning to room temperature. Helium leak tests were performed at each test point to determine seal performance. The two major test objectives were to establish that butyl rubber material would maintain its integrity under various conditions and within specified parameters and to evaluate changes in material properties.

  2. The touchscreen operant platform for testing working memory and pattern separation in rats and mice

    PubMed Central

    Oomen, Charlotte A.; Hvoslef-Eide, Martha; Heath, Christopher J.; Mar, Adam C.; Horner, Alexa E.; Bussey, Timothy J.; Saksida, Lisa M.

    2014-01-01

    The automated touchscreen operant chamber for rats and mice allows for the assessment of multiple cognitive domains within the same testing environment. This protocol presents the Location Discrimination task (LD) and the Trial-Unique delayed Nonmatching-to-Location task (TUNL), which both assess memory for location. On these tasks, animals are trained to a pre-defined criterion during ~20-40 daily sessions. In LD-sessions, touching the same location on the screen is rewarded on consecutive trials, followed by a reversal of location-reward contingencies. TUNL, a working memory task, requires animals to “non-match” to a sample location after a delay. In both LD and TUNL spatial similarity can be varied, allowing assessment of “pattern separation” ability, a function thought to be performed by the dentate gyrus. These tasks are therefore particularly useful in animal models of hippocampal, and specifically dentate gyrus function, but additionally permit discernment of changes in pattern separation from those in working memory. PMID:24051961

  3. Sarcoidosis: correlation of pulmonary parenchymal pattern at CT with results of pulmonary function tests

    SciTech Connect

    Bergin, C.J.; Bell, D.Y.; Coblentz, C.L.; Chiles, C.; Gamsu, G.; MacIntyre, N.R.; Coleman, R.E.; Putman, C.E.

    1989-06-01

    The appearances of the lungs on radiographs and computed tomographic (CT) scans were correlated with degree of uptake on gallium scans and results of pulmonary function tests (PFTs) in 27 patients with sarcoidosis. CT scans were evaluated both qualitatively and quantitatively. Patients were divided into five categories on the basis of the pattern of abnormality at CT: 1 = normal (n = 4); 2 = segmental air-space disease (n = 4); 3 = spherical (alveolar) masslike opacities (n = 4); 4 = multiple, discrete, small nodules (n = 6); and 5 = distortion of parenchymal structures (fibrotic end-stage sarcoidosis) (n = 9). The percentage of the volume judged to be abnormal (CT grade) was correlated with PFT results for each CT and radiographic category. CT grades were also correlated with gallium scanning results and percentage of lymphocytes recovered from bronchoalveolar lavage (BAL). Patients in CT categories 1 and 2 had normal lung function, those in category 3 had mild functional impairment, and those in categories 4 and 5 showed moderate to severe dysfunction. The overall CT grade correlated well with PFT results expressed as a percentage of the predicted value. In five patients, CT scans showed extensive parenchymal disease not seen on radiographs. CT grades did not correlate with the results of gallium scanning or BAL lymphocytes. The authors conclude that patterns of parenchymal sarcoidosis seen at CT correlate with the PFT results and can be used to indicate respiratory impairment.

  4. An Experimental and Theoretical Study of Fracture Patterns and Particle Motion Generated by Underground Explosions

    NASA Astrophysics Data System (ADS)

    Mihaly, J. M.; Rosakis, A.; Sammis, C. G.; Bhat, H.

    2013-12-01

    Fracture patterns and local particle velocities produced by point explosions in very brittle 'candy glass' plates are compared to those numerically predicted using a dynamic micro-mechanical damage mechanics model, developed by Bhat, Rosakis and Sammis, J. Appl. Mech., 2012. Empirically measured material properties for candy glass facilitate direct comparison between the numerical simulation and experimental results. The evolution of fracture damage produced in experiments is observed using high-speed digital photography, which also images resultant wave fronts (for both P and S). Local particle velocities are also recorded at up to three points using laser vibrometers. Numerical results for the spatial extent of circumferential and radial cracking, in addition to the growth-rate of individual radial cracks, are representative of experimental observations. Wave reflections from the plate edges are observed in both experiment and numerical simulation to affect the expansion of radial cracks. Numerically predicted wave-forms and arrivals compare well with experimental results observed at select points.

  5. A framework for prevention: changing health-damaging to health-generating life patterns.

    PubMed Central

    Milio, N

    1976-01-01

    A set of propositions is offered to provide a frame of reference for proposed strategies to improve healthful behavior by placing personal choice-making in the context of societal option-setting. The health status of populations at a given point in time is seen as a result of customary personal choice-making. These choices in turn are limited by both the perceived and actual options available to individuals, depending on their personal and their community's resources, from which to make choices. Most people, most of the time will make the easiest choices, i.e., will do the things, develop the patterns or life-styles, which seem to cost them less and/or from which they will gain more of what they value in tangible and/or intangible terms. PMID:1275116

  6. Comparing patterns of nucleotide substitution rates among chloroplast loci using the relative ratio test.

    PubMed

    Muse, S V; Gaut, B S

    1997-05-01

    Even when several genetic loci are used in molecular evolutionary studies, each locus is typically analyzed independently of the others. This type of approach makes it difficult to study mechanisms and processes that affect multiple genes. In this work we develop a statistical approach for the joint analysis of two or more loci. The tests we propose examine whether or not nucleotide substitution rates across evolutionary lineages have the same relative proportions at two loci. Theses procedures are applied to 33 genes from the chloroplast genomes of rice, tobacco, pine, and liverwort. With the exception of five clearly distinct loci, we find that synonymous substitution rates tend to change proportionally across genes. We interpret these results to be consistent with a "lineage effect" acting on the entire chloroplast genome. In contrast, nonsynonymous rates do not change proportionally across genes, suggesting that locus-specific evolutionary effects dominate patterns of nonsynonymous substitution. PMID:9136027

  7. Evaluation of novel second-generation RSV and influenza rapid tests at the point of care.

    PubMed

    Tuttle, Ryan; Weick, Anja; Schwarz, Wiebke Sabrina; Chen, Xi; Obermeier, Patrick; Seeber, Lea; Tief, Franziska; Muehlhans, Susann; Karsch, Katharina; Peiser, Christian; Duwe, Susanne; Schweiger, Brunhilde; Rath, Barbara

    2015-03-01

    Acute respiratory infections represent common pediatric emergencies. Infection control warrants immediate and accurate diagnoses. In the past, first-generation respiratory syncytial virus (RSV) rapid tests (strip tests) have shown suboptimal sensitivities. In 2013, the Food and Drug Administration licensed a second-generation RSV rapid test providing user-independent readouts (SOFIA™-RSV) using automated fluorescence assay technology known to yield superior results with influenza rapid testing. We are reporting the first point-of-care evaluation of the SOFIA™-RSV rapid test. In the Charité Influenza-Like Disease Cohort, 686 nasopharyngeal samples were tested in parallel with SOFIA™-RSV and SOFIA™-Influenza A+B. Compared to real-time PCR, SOFIA™-RSV sensitivities/specificities were 78.6%/93.9%, respectively (SOFIA™-Influenza A: 80.6%/99.3%). Performance was greatest in patients below 2 years of age with a test sensitivity of 81.8%. RSV sensitivities were highest (85%) in the first 2 days of illness and with nasopharyngeal compared to nasal swabs (P=0.055, McNemar's test). Second-generation RSV and influenza rapid testing provides highly accurate results facilitating timely patient cohortation and management. PMID:25583129

  8. Progress in updatable photorefractive polymer-based holographic displays via direct optical writing of computer-generated fringe patterns

    NASA Astrophysics Data System (ADS)

    Jolly, Sundeep; Barabas, James; Smalley, Daniel; Bove, V. Michael

    2013-03-01

    We have previously introduced an architecture for updatable photorefractive holographic display based around direct fringe writing of computer-generated holographic fringe patterns. In contrast to interference-based stereogram techniques for hologram exposure in photorefractive polymer (PRP) materials, the direct fringe writing architecture simplifies system design, reduces system footprint and cost, and offers greater affordances over the types of holographic images that can be recorded. In this paper, motivations and goals for employing a direct fringe writing architecture for photorefractive holographic imagers are reviewed, new methods for PRP exposure by micro-optical fields generated via spatial light modulation and telecentric optics are described, and resulting holographic images are presented and discussed. Experimental results are reviewed in the context of theoretical indicators for system performance.

  9. Patterns of mortality in second generation Irish living in England and Wales: longitudinal study.

    PubMed Central

    Harding, S.; Balarajan, R.

    1996-01-01

    OBJECTIVE--To examine the mortality of second generation Irish living in England and Wales. DESIGN--Longitudinal study of 1% of the population of England and Wales (longitudinal study by the Office of Population Censuses and Surveys (now the Office for National Statistics)) followed up from 1971 to 1989. SUBJECTS--3075 men and 3233 women aged 15 and over in 1971. MAIN OUTCOME MEASURES--Age and sex specific standardised mortality ratios for all causes, cancers, coronary heart disease, cerebrovascular diseases, respiratory diseases, and injuries and poisonings. Deaths were also analysed by socioeconomic indicators. RESULTS--786 deaths were traced to men and 762 to women. At working ages (men, aged 15-64; women, 15-59) the mortality of men (standardised mortality ratio 126) and women (129) was significantly higher than that of all men and all women. At ages 15-44, relative disadvantages were even greater both for men (145) and for women (164). Mortality was raised for most major causes of death. Significant excess mortality from cancers was seen for men of working age (132) and for women aged 60 and over (122). At working ages mortality of the second generation Irish in every social class and in the categories of car access and housing tenure was higher than that of all men and all women in the corresponding categories. Adjusting for these socioeconomic indicators did not explain the excess mortality. CONCLUSION--Mortality of second generation Irish men and women was higher than that of all men and all women and for most major causes of death. While socioeconomic factors remain important, cultural and lifestyle factors are likely to contribute to this adverse mortality. PMID:8646095

  10. Observing and predicting the spatial-temporal pattern of runoff generation processes from the watershed to the regional scale

    NASA Astrophysics Data System (ADS)

    Weiler, M.

    2012-12-01

    Runoff generation processes are the key to understand and predict watershed dynamics and behaviour under current as well as under changing conditions. A variety of approaches have been developed to observe these processes at the plot scale (e.g. infiltration and sprinkling experiments), the hillslope scale (soil moisture and piezometer networks and trenching) and the watershed scale (hydrograph separation with stable isotopes and natural tracers). However, predicting the four major runoff generation mechanisms (infiltration excess, saturation excess, subsurface flow and deep percolation) without detailed observation in ungauged watershed is still a challenge, but a prerequisite to track water flow pathways and to make adequate prediction for hydrological extremes. Methods have been developed to map dominant runoff generation processes in the field and with digital maps, however, these methods are often static and do not consider the temporal dynamics of runoff generation processes frequently observed with the various experimental approaches. The recently developed parsimonious rainfall-runoff model DROGen can bridge the gap between across spatial scales in ungauged watersheds since parameters are not calibrated. The model incorporates high-resolution GIS data (1m resolution DEM, land-use, impervious surfaces), hydro-geological and pedological data as well as information about the effect of macropores and preferential flow pathways on runoff generation processes with a comprehensive knowledge base from various field observations and experiments. The model was applied to over 6500 meso-scale watershed in the State of Baden-Württemberg in Germany and 15 gauged watersheds were selected for detailed model evaluation. The evaluation was done with field-mapping of runoff generation processes for direct comparison with the simulated pattern of runoff processes for different types of precipitation (high intensity and short duration / low intensity and long duration) and benchmarking of several observed floods in these watersheds. The simulated patterns were analysed in more detail to gain a better understanding of the initial conditions (soil moisture) and different precipitation events and to derive scaling relationships. The model DROGen is different from many other model approaches not only with respect to spatial resolution and model calibration, but in particular by incorporating a detailed understanding of hydrological processes, obtained from many experimental studies on runoff generation at the plot and hillslope scale worldwide.

  11. FABRICATE AND TEST AN ADVANCED NON-POLLUTING TURBINE DRIVE GAS GENERATOR

    SciTech Connect

    Eugene Baxter; Roger E. Anderson; Stephen E. Doyle

    2003-06-01

    In September 2000 the Department of Energy's National Energy Technology Laboratory (DOE/NETL) contracted with Clean Energy Systems, Inc. (CES) of Sacramento, California to design, fabricate, and test a 20 MW{sub t} (10 MW{sub e}) gas generator. Program goals were to demonstrate a non-polluting gas generator at temperatures up to 3000 F at 1500 psi, and to demonstrate resulting drive gas composition, comprising steam and carbon dioxide substantially free of pollutants. Following hardware design and fabrication, testing, originally planned to begin in the summer of 2001, was delayed by unavailability of the contracted test facility. CES designed, fabricated, and tested the proposed gas generator as originally agreed. The CES process for producing near-zero-emissions power from fossil fuels is based on the near-stoichiometric combustion of a clean gaseous fuel with oxygen in the presence of recycled water, to produce a high-temperature, high-pressure turbine drive fluid comprising steam and carbon dioxide. Tests demonstrated igniter operation over the prescribed ranges of pressure and mixture ratios. Ignition was repeatable and reliable through more than 100 ignitions. Injector design ''A'' was operated successfully at both low power ({approx}20% of rated power) and at rated power ({approx}20 MW{sub t}) in more than 95 tests. The uncooled gas generator configuration (no diluent injectors or cooldown chambers installed) produced drive gases at temperatures approaching 3000 F and at pressures greater than 1550 psia. The fully cooled gas generator configuration, with cooldown chambers and injector ''A'', operated consistently at pressures from 1100 to 1540 psia and produced high pressure, steam-rich turbine drive gases at temperatures ranging from {approx}3000 to as low as 600 F. This report includes description of the intended next steps in the gas generator technology demonstration and traces the anticipated pathway to commercialization for the gas generator technology developed in this program.

  12. Structural testing of the Los Alamos National Laboratory Heat Source/Radioisotopic Thermoelectric Generator shipping container

    SciTech Connect

    Bronowski, D.R.; Madsen, M.M.

    1991-06-01

    The Heat Source/Radioisotopic Thermoelectric Generator shipping container is a Type B packaging design currently under development by Los Alamos National Laboratory. Type B packaging for transporting radioactive material is required to maintain containment and shielding after being exposed to the normal and hypothetical accident environments defined in Title 10 Code of Federal Regulations Part 71. A combination of testing and analysis is used to verify the adequacy of this package design. This report documents the test program portion of the design verification, using several prototype packages. Four types of testing were performed: 30-foot hypothetical accident condition drop tests in three orientations, 40-inch hypothetical accident condition puncture tests in five orientations, a 21 psi external overpressure test, and a normal conditions of transport test consisting of a water spray and a 4 foot drop test. 18 refs., 104 figs., 13 tabs.

  13. Genetic counselors' (GC) knowledge, awareness, understanding of clinical next-generation sequencing (NGS) genomic testing.

    PubMed

    Boland, P M; Ruth, K; Matro, J M; Rainey, K L; Fang, C Y; Wong, Y N; Daly, M B; Hall, M J

    2015-12-01

    Genomic tests are increasingly complex, less expensive, and more widely available with the advent of next-generation sequencing (NGS). We assessed knowledge and perceptions among genetic counselors pertaining to NGS genomic testing via an online survey. Associations between selected characteristics and perceptions were examined. Recent education on NGS testing was common, but practical experience limited. Perceived understanding of clinical NGS was modest, specifically concerning tumor testing. Greater perceived understanding of clinical NGS testing correlated with more time spent in cancer-related counseling, exposure to NGS testing, and NGS-focused education. Substantial disagreement about the role of counseling for tumor-based testing was seen. Finally, a majority of counselors agreed with the need for more education about clinical NGS testing, supporting this approach to optimizing implementation. PMID:25523111

  14. Effects of the insect growth regulator pyriproxyfen in a two-generation test with Chironomus riparius.

    PubMed

    Tassou, Koffi T; Schulz, Ralf

    2009-05-01

    Pyriproxyfen a juvenile hormone analoga (JHA) was used in a two-generation test with Chironomus riparius (Diptera). The protocol is an extension of the OECD test methods to test duration from first-instar larvae in the parental (P) generation to emergence of midges in the filial (F1) generation. Test species were exposed to concentrations ranging from 0.001 to 0.1mg/L. The results showed significant adverse effects compared to the solvent control for emergence rate (p<0.001), development rate (p<0.001), fecundity (p<0.05) and fertility of egg ropes but not for the sex ratio. No observed effect concentrations (NOEC), respectively, lowest observed effect concentration (LOEC) values were lower for emergence rate and development rate in the F1 (0.003mg/L, respectively, 0.01mg/L each) than in the P generation (0.01mg/L, respectively, 0.03mg/L). The two-generation test provided additional information, which might be useful in the risk assessment of agrochemicals with potential endocrine effects. PMID:19285344

  15. Generation of a large gene/protein lexicon by morphological pattern analysis.

    PubMed

    Tanabe, Lorraine; Wilbur, W John

    2004-01-01

    The identification of gene/protein names in natural language text is an important problem in named entity recognition. In previous work we have processed MEDLINE documents to obtain a collection of over two million names of which we estimate that perhaps two thirds are valid gene/protein names. Our problem has been how to purify this set to obtain a high quality subset of gene/protein names. Here we describe an approach which is based on the generation of certain classes of names that are characterized by common morphological features. Within each class inductive logic programming (ILP) is applied to learn the characteristics of those names that are gene/protein names. The criteria learned in this manner are then applied to our large set of names. We generated 193 classes of names and ILP led to criteria defining a select subset of 1,240,462 names. A simple false positive filter was applied to remove 8% of this set leaving 1,145,913 names. Examination of a random sample from this gene/protein name lexicon suggests it is composed of 82% (+/-3%) complete and accurate gene/protein names, 12% names related to genes/proteins (too generic, a valid name plus additional text, part of a valid name, etc.), and 6% names unrelated to genes/proteins. The lexicon is freely available at ftp.ncbi.nlm.nih.gov/pub/tanabe/Gene.Lexicon. PMID:15290756

  16. [Toward a metabolic approach of the central pattern generator concept in a spinal rat model].

    PubMed

    Rigoard, P; Buffenoir, K; Fares, M; Chaillou, M; Da Costa, L; Boildieu, N; Seguin, F; Huze, C; Schaeffer, L; Lapierre, F; Maixent, J-M

    2009-03-01

    It has been shown that the onset of a central nervous system lesion in the rat results in morphological modifications of the peripheral nerves and the underlying neuromuscular junctions, without suggesting a functional correlation between recuperation of motor functions and sublesional metabolic activity. Using double lesion localization (T2 and T6) in a spinal rat model has nevertheless pointed out the functional importance of the T2-T6 metameric interval in the reinnervation phenomena observed, raising the problem of spinal generation in locomotor movements. Motivated by electrophysiological data that have given support to the concept of an anatomic substrate for these intramedullary rhythm generators, we attempted to establish a relation between the functional recuperation possible after a central nervous system lesion and modifications within the metabolism of the underlying neuromuscular system. We notably focused on Na/K-ATPase, whose crucial role in neuromuscular transmission has been evidenced. This paper proposes to demonstrate the involvement in the mechanisms of metabolic regulation after trans-synaptic denervation, i.e., a central nervous system lesion. Our study includes the Na/K-ATPase activity analysis on the sublesional peripheral nerve and the combined analysis of the expression of different RNA messengers within the corresponding muscle groups. We have also investigated the spatiotemporal organization of the compensating processes of the nerves underlying the lesion using magnetic resonance spectroscopy. PMID:19230942

  17. Experiments evaluating subsidence generated within a subaqueous deformable substrate due to varying differential sediment loading patterns

    NASA Astrophysics Data System (ADS)

    Foreman, B.; Chatmas, E. S.; Abeyta, A.; Paola, C.

    2013-12-01

    The intraslope areas of many passive margins display a complex bathymetry of topographic depressions and crests that form series of minibasins. These minibasins are linked to the deformation of subsurface salt layers and act as localized sediment traps. Many mechanisms have been proposed for the initiation of minibasins, including tectonic forces (both extensional and contractional), regional gravitational sliding, density inversion between salt layers and overburden, and differential sediment loading. Regardless of initiation mechanism, it is widely recognized that synkinematic deposition plays a active role in determining subsidence patterns and sediment routing within and among the minibasins. We undertook a series of simplified 1-D and 2-D experiments 1) to evaluate the feasibility of developing a series of well-defined minibasins created exclusively by differential sediment loading and 2) to quantitatively determine the effects of substrate thickness, density contrast, and sedimentation rate on the resultant subsidence pattern. We also present an initial non-dimensionalized formulation of the problem that relates density contrasts, clinoform thickness, substrate thickness, progradation rate, and viscosity of the deformable substrate. Two sets of experiments were performed. The first set (1-D) vertically loaded a subaqueous corn syrup substrate (capturing the rheology of subsurface salt as a Newtonian fluid) with walnut sand. The second set (2-D) of experiments prograded a walnut sediment clinoform across a corn syrup substrate. We systematically varied sedimentation rate, substrate thickness, and, in the case of the prograding clinoform, base level. In no cases did we successfully reproduce a series of minibasins similar to those observed in natural settings. Instead the substrate was simply displaced laterally as sediment was deposited, forming a single depression. High sedimentation rates tended to produce wider zones of subsidence, however, if given sufficient time subsidence tended towards a similar overall geometry for both slow and fast sedimentation rates. This occurred as long as a sufficiently thick substrate was maintained. In our experiments, this was a ratio greater than 1:4 of substrate-to-clinoform thickness. When the substrate is insufficiently thick, weld structures formed as the overlying sediments were deposited onto the base of the flume. These structures appear similar to salt welds in natural systems. We also noted small zones of enhanced subsidence below the toeset and foreset of the prograding clinoform as sediment was deposited. These minor features are approximately one tenth the size of the overall basin formed in the substrate, and locally trap additional sediment during progradation. These are potentially related to infrequent grain flow events. Overall our experiments suggest that sediment differential loading is an insufficient mechanism in isolation to produce series of minibasins, but that the loading does significantly affect the initial geometry and rate of subsidence within these basins.

  18. A new generation of progressive mask defects on the pattern side of advanced photomasks

    NASA Astrophysics Data System (ADS)

    Grenon, Brian J.; Bhattacharyya, Kaustuve; Eynon, Benjamin

    2006-06-01

    The progressive mask defect problem is an industry-wide mask reliability issue. Even if masks are determined to be clean upon arrival from the mask supplier, some of these masks can show catastrophic defect growth over the course of production usage in the fab. The categories of defects that cause reticle-quality degradation over time are defined as progressive defects, commonly known as crystal growth, haze, fungus or precipitate. This progressive defect problem has been around for more than a decade and was observed at almost every lithographic wavelength. This problem is especially severe at 193nm lithography. Triggering the increased severity are shorter wavelength lithography - where the photons are highly energized - and the concurrent transition to 300 mm wafers, which require photomasks to endure more prolonged exposure as compared to 200 mm wafers. Both embedded phase shift masks (EPSMs) and chrome-on-glass masks are affected by progressive defects. These defects are generally found on the patterned surface underneath the pellicle (on clear, half-tone or chrome patterns), as well as on the backside surface of the masks. Past cases have indicated that this problem mainly starts on the scribes and borders, with emerging semi-transmissive contamination of ~100nm. These defects then propagate into the die area while growing in both size and opaqueness. Compositional analysis has shown that the majority of these defects are ammonium sulfate. However, since significant effort focused on the elimination of ammonium sulfate a new trend has emerged. Current studies show severe defect growth consists of organic contaminants (ammonium oxalate, cyanuric acid etc.) on half-tone edges and on chromium edges. The sources for progressive defect mechanisms are under investigation, though several candidates have been considered: maskmaking materials and process residues (mainly ammonium or sulfate ions), the fab environment, or the stepper environment. Controlling or balancing these sources may help to reduce the frequency at which these defects occur, but thus far has been unable to eliminate the problem. With each successive device shrink, the resultant changes in lithographic wavelength and processing within the mask fabrication facility and IC fab disrupt the fine balance among the above suspected defect sources, resulting in the return of catastrophic progressive defect growth. Due to this uncertainty, strict mask quality monitoring in the fab is essential. The ideal reticle quality control goal in a fab should be to detect any nascent progressive defects before they become yield limiting. Hence, the masks should be monitored on an established frequency that allows problem masks to be removed from production and sent for rework prior to impacting device performance and fab yield.

  19. Using Patterns of Summed Scores in Paper-and-Pencil Tests and Computer-Adaptive Tests to Detect Misfitting Item Score Patterns

    ERIC Educational Resources Information Center

    Meijer, Rob R.

    2004-01-01

    Two new methods have been proposed to determine unexpected sum scores on sub-tests (testlets) both for paper-and-pencil tests and computer adaptive tests. A method based on a conservative bound using the hypergeometric distribution, denoted p, was compared with a method where the probability for each score combination was calculated using a…

  20. The Growing Canvas of Biological Development: Multiscale Pattern Generation on an Expanding Lattice of Gene Regulatory Nets

    NASA Astrophysics Data System (ADS)

    Doursat, René

    The spontaneous generation of an entire organism from a single cell is the epitome of a self-organizing, decentralized complex system. How do nonspatial gene interactions extend in 3-D space? In this work, I present a simple model that simulates some biological developmental principles using an expanding lattice of cells. Each cell contains a gene regulatory network (GRN), modeled as a feedforward hierarchy of switches that can settle in various on/off expression states. Local morphogen gradients provide positional information in input, which is integrated by each GRN to produce differential expression of identity genes in output. Similarly to striping in the Drosophila embryo, the lattice becomes segmented into spatial regions of homogeneous genetic expression that resemble stained-glass motifs. Meanwhile, it also expands by cell proliferation, creating new local gradients of positional information within former single-identity regions. Analogous to a "growing canvas" painting itself, the alternation of growth and patterning results in the creation of a form. This preliminary study attempts to reproduce pattern formation through a multiscale, recursive and modular process. It explores the elusive relationship between nonspatial GRN weights (genotype) and spatial patterns (phenotype). Abstracting from biology in the same spirit as neural networks or swarm optimization, I hope to be contributing to a novel engineering paradigm of system construction that could complement or replace omniscient architects with decentralized collectivities of agents.