Sample records for equivalent trap tasks

  1. Hierarchical IRT Examination of Isomorphic Equivalence of Complex Constructed Response Tasks.

    ERIC Educational Resources Information Center

    Williamson, David M.; Johnson, Matthew S.; Sinharay, Sandip; Bejar, Isaac I.

    This paper explores the application of a technique for hierarchical item response theory (IRT) calibration of complex constructed response tasks that has promise both as a calibration tool and as a means of evaluating the isomorphic equivalence of complex constructed response tasks. Isomorphic tasks are explicitly and rigorously designed to be…

  2. On the Equivalence of Trapped Colloids, Pinned Vortices, and Spin Ice

    SciTech Connect

    Nisoli, Cristiano [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-04-23

    We investigate the recently reported analogies between pinned vortices in nano-structured superconductors or colloids in optical traps, and spin ice materials. The frustration of the two models, one describing colloids and vortices, the other describing spin ice, differs essentially. However, their effective energetics is made identical by the contribution of an emergent field associated to a topological charge. This equivalence extends to the local low-energy dynamics of the ice manifold, yet breaks down in lattices of mixed coordination, because of topological charge transfer between sub-latices.

  3. Does The Principle Of Equivalence Prevent Trapped Surfaces From Being Formed In The General Relativistic Collapse Process?

    E-print Network

    Darryl Leiter; Stanley Robertson

    2002-12-11

    It has been recently shown (Mitra,- astro-ph/9910408, astro-ph/0207056) that the timelike spherical collapse of a radiating, physical fluid in General Relativity, as seen by an interior co-moving observer at rest in the physical fluid, does not permit formation of ``trapped surfaces''. This followed from the fact that the formation of a trapped surface in a physical fluid would cause the timelike world lines of the collapsing fluid to become null at the would be trapped surface, thus violating the Principle of Equivalence in General Theory of Relativity. In this paper we generalize and extend this result by studying the problem from the point of view of the exterior Vaidya metric of a collapsing radiating fluid as seen by an exterior stationary observer, and find that the "no trapped surface condition" becomes g00 > 0 consistent with that obtained for the interior co-moving metric. Since we have shown that the Principle of Equivalence prevents trapped surfaces from being formed in collapsing, radiating objects, then true event horizons cannot exist and Galactic Black Hole Candidates (GBHC) must have physically observable intrinsic magnetic dipole moments. Because of this fact it follows (Robertson and Leiter - astro-ph/0102381, astro-ph/0208333) that GBHC can be consistently described, within the framework of General Relativity, in terms of a magneto-spheric eternally collapsing objects (MECO) without true event horizons.

  4. Prevalence learning and decision making in a visual search task: an equivalent ideal observer approach

    NASA Astrophysics Data System (ADS)

    He, Xin; Samuelson, Frank; Zeng, Rongping; Sahiner, Berkman

    2015-03-01

    Research studies have observed an influence of target prevalence on observer performance for visual search tasks. The goal of this work is to develop models for prevalence effects on visual search. In a recent study by Wolfe et. al, a large scale observer study was conducted to understand the effects of varying target prevalence on visual search. Particularly, a total of 12 observers were recruited to perform 1000 trials of simulated baggage search as target prevalence varied sinusoidally from high to low and back to high. We attempted to model observers' behavior in prevalence learning and decision making. We modeled the observer as an equivalent ideal observer (EIO) with a prior belief of the signal prevalence. The use of EIO allows the application of ideal observer mathematics to characterize real observers' performance reading real-life images. For every given new image, the observer updates the belief on prevalence and adjusts his/her decision threshold according to utility theory. The model results agree well with the experimental results from the Wolfe study. The proposed models allow theoretical insights into observer behavior in learning prevalence and adjusting their decision threshold.

  5. New head equivalent phantom for task and image performance evaluation representative for neurovascular procedures occurring in the Circle of Willis

    NASA Astrophysics Data System (ADS)

    Ionita, Ciprian N.; Loughran, Brendan; Jain, Amit; Swetadri Vasan, S. N.; Bednarek, Daniel R.; Levy, Elad; Siddiqui, Adnan H.; Snyder, Kenneth V.; Hopkins, L. N.; Rudin, Stephen

    2012-03-01

    Phantom equivalents of different human anatomical parts are routinely used for imaging system evaluation or dose calculations. The various recommendations on the generic phantom structure given by organizations such as the AAPM, are not always accurate when evaluating a very specific task. When we compared the AAPM head phantom containing 3 mm of aluminum to actual neuro-endovascular image guided interventions (neuro-EIGI) occurring in the Circle of Willis, we found that the system automatic exposure rate control (AERC) significantly underestimated the x-ray parameter selection. To build a more accurate phantom for neuro-EIGI, we reevaluated the amount of aluminum which must be included in the phantom. Human skulls were imaged at different angles, using various angiographic exposures, at kV's relevant to neuro-angiography. An aluminum step wedge was also imaged under identical conditions, and a correlation between the gray values of the imaged skulls and those of the aluminum step thicknesses was established. The average equivalent aluminum thickness for the skull samples for frontal projections in the Circle of Willis region was found to be about 13 mm. The results showed no significant changes in the average equivalent aluminum thickness with kV or mAs variation. When a uniform phantom using 13 mm aluminum and 15 cm acrylic was compared with an anthropomorphic head phantom the x-ray parameters selected by the AERC system were practically identical. These new findings indicate that for this specific task, the amount of aluminum included in the head equivalent must be increased substantially from 3 mm to a value of 13 mm.

  6. Depth dependence of absorbed dose, dose equivalent and linear energy transfer spectra of galactic and trapped particles in polyethylene and comparison with calculations of models

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Cucinotta, F. A.; Wilson, J. W. (Principal Investigator)

    1998-01-01

    A matched set of five tissue-equivalent proportional counters (TEPCs), embedded at the centers of 0 (bare), 3, 5, 8 and 12-inch-diameter polyethylene spheres, were flown on the Shuttle flight STS-81 (inclination 51.65 degrees, altitude approximately 400 km). The data obtained were separated into contributions from trapped protons and galactic cosmic radiation (GCR). From the measured linear energy transfer (LET) spectra, the absorbed dose and dose-equivalent rates were calculated. The results were compared to calculations made with the radiation transport model HZETRN/NUCFRG2, using the GCR free-space spectra, orbit-averaged geomagnetic transmission function and Shuttle shielding distributions. The comparison shows that the model fits the dose rates to a root mean square (rms) error of 5%, and dose-equivalent rates to an rms error of 10%. Fairly good agreement between the LET spectra was found; however, differences are seen at both low and high LET. These differences can be understood as due to the combined effects of chord-length variation and detector response function. These results rule out a number of radiation transport/nuclear fragmentation models. Similar comparisons of trapped-proton dose rates were made between calculations made with the proton transport model BRYNTRN using the AP-8 MIN trapped-proton model and Shuttle shielding distributions. The predictions of absorbed dose and dose-equivalent rates are fairly good. However, the prediction of the LET spectra below approximately 30 keV/microm shows the need to improve the AP-8 model. These results have strong implications for shielding requirements for an interplanetary manned mission.

  7. Moderate Intense Physical Activity Depends on Selected Metabolic Equivalent of Task (MET) Cut-Off and Type of Data Analysis

    PubMed Central

    Langer, Daniel; Hornikx, Miek; Demeyer, Heleen; Burtin, Chris; Decramer, Marc; Gosselink, Rik; Janssens, Wim; Troosters, Thierry

    2013-01-01

    Background Accelerometry data are frequently analyzed without considering whether moderate-to-vigorous physical activities (MVPA) were performed in bouts of >10 minutes as defined in most physical activity guidelines. We aimed i) to quantify MVPA by using different commonly-applied physical activity guidelines, ii) to investigate the effect of bouts versus non-bouts analysis, and iii) to propose and validate a MVPA non-bouts cut-point to classify (in-) active subjects. Methods Healthy subjects (n=110;62±6yrs) and patients with Chronic Obstructive Pulmonary Disease (COPD) (n=113;62±5yrs) wore an activity monitor for 7 days. Three Metabolic Equivalent of Task (MET) cut-offs and one individual target (50% VO2 reserve) were used to define MVPA. First, all minutes of MVPA were summed up (NON-BOUTS). Secondly, only minutes performed in bouts of >10 minutes continuous activity were counted (BOUTS). Receiver operating characteristic (ROC) curve analyses were used to propose and (cross-) validate new MVPA non-bout cut-points based on the criterion of 30 minutes MVPA per day (BOUTS). Likelihood ratios (sensitivity/[1-specificity]) were used to express the association between the proposed MVPA non-bout target and the MVPA bout target of 30 min*day-1. Results MVPA was variable across physical activity guidelines with lowest values for age-specific cut-offs. Selecting a METs cut-point corresponding to 50% VO2 reserve revealed no differences in MVPA between groups. MVPA’s analyzed in BOUTS in healthy subjects were 2 to 4 fold lower than NON-BOUTS analyses and this was even 3 to 12 fold lower in COPD. The MVPA non-bouts cut-point of 80 min*day-1 using a 3 METs MVPA threshold delivered positive likelihood ratios of 5.1[1.5-19.6] (healthy subjects) and 2.3[1.6-3.3] (COPD). Conclusion MVPA varies upon the selected physical activity guideline/targets and bouts versus non-bouts analysis. Accelerometry measured MVPA non-bouts target of 80 min*day-1, using a 3 METs MVPA threshold, is associated to the commonly-used MVPA bout target of 30 min*day-1. PMID:24376804

  8. Tasks

    Microsoft Academic Search

    Paresh Malhotra; Keith Muir; Ian Reeves; George Duncan; Katrina Livingstone; Hazel Jackson; Caroline Hogg; Pauline Castle; Gemma Learmonth; Monika Harvey

    2007-01-01

    It is well established that patients with hemispatial neglect present with severe visuospatial impairments, but studies that have directly investigated visuomotor control have revealed diverging results, with some studies showing that neglect patients perform relatively better on such tasks. The present study compared the visuomotor performance of patients with and without neglect after right- hemisphere stroke with those of age-matched

  9. The reliability and validity of a lift simulator and its functional equivalence with free weight lifting tasks

    Microsoft Academic Search

    Patrick J. Sparto; Mohamad Parnianpour; Kinda A. Khalaf; Sheldon R. Simon

    1995-01-01

    The combination of Workers' Compensation legal claims and the enactment of the Americans with Disabilities Act (1990) has created a need for more objective and realistic trunk muscle testing. The LIDOLift (Loredan, Inc.) is a computerized dynamometer which has the capabilities to test multijoint coordinated lifting tasks in isometric, isokinetic, and isoinertial modes of operation. The calibration of the electromechanical

  10. Search, Enumeration, and Aging: Eye Movement Requirements Cause Age-Equivalent Performance in Enumeration but Not in Search Tasks

    Microsoft Academic Search

    Derrick G. Watson; Elizabeth A. Maylor; Lucy A. M. Bruce

    2005-01-01

    Response time (RT) and fixation frequency were measured for young and older adults in search and enumeration tasks under high- and low-attentional competition conditions. There was an age-related decrement in search rates for single targets both for RT and fixation frequency, but there was no deficit in enumeration rates either with or without distractors even though serial enumeration rates were

  11. Facilitation of the equivalence--equivalence responding.

    PubMed

    Pérez Fernández, Vicente Jesús; García García, Andrés; Gómez Bujedo, Jesús

    2011-08-01

    Equivalence-Equivalence responding, based on equivalence class formation, is a key concept of the functional-analytic model of analogical reasoning held by RFT theorists. Relational stimulus control is supposed to play an important role in this arbitrary relational response. Previous research showed that mere training of the prerequisites for equivalence class formation is not always enough for the derivation of equivalence-equivalence responding, even in adults. In the first experiment, with 12 adult participants, we designed a matching-to-sample training and testing procedure that, although it provided all necessary conditions, did not lead to Equivalence-Equivalence responding in most participants, so that the efficacy of a facilitation procedure could be assessed. In Experiment 2, with 32 valid participants, a matching-to-sample procedure based on non-arbitrary relations was introduced to assess its efficacy in enhancing stimulus control by the relational properties of sample and comparisons. Results showed a moderate effect: 40.6% of the participants passed the test after being exposed to a non-arbitrary relational matching task (but none without it). This research underlines the importance of non-arbitrary relational responses in the derivation of more complex repertoires. PMID:21774893

  12. Storm- and tide-dominated shorelines in Cretaceous Moosebar-lower Gates interval-outcrop equivalents of Deep basin gas trap in western Canada

    SciTech Connect

    Leckie, D.A., Walker, R.G.

    1982-02-01

    The Moosebar and Gates Formations crop out in the deformed Foothills belt south of Fort St. John, British Columbia. They permit examination of the depositional environments of sandstones and conglomerates that are gas-bearing in the equivalent Wilrich-Falher interval of the Deep basin of Alberta and British Columbia. The Moosebar-Gates interval consists of several upward-coarsening and marine to nonmarine sequences. Moosebar bioturbated shales pass upward into turbidites and offshore storm deposits. Flow directions indicate a north-dipping paleoslope. A second coarsening-upward sequence at the top of the Moosebar and base of the Gates terminates in a lenticular fluvial conglomerate up to 30 m thick, which is overlain by coals, carbonaceous mudstones, and sandstones. Above the carbonaceous zone, fluvial conglomerates in the south grade into beach conglomerates northward. The upper part of the beach conglomerate consists of exposed three-dimensional storm berms, at least 500 m long, up to 1.5 m high, with wavelengths of 12 to 24 m. The berms trend east-west. Seaward of the conglomerate beach are herringbone cross-bedded (tidal) sandstones with a marine trace fauna. Graded sharp-based conglomerates also are present. Farther north, at the same stratigraphic level, is a series of partly overlapping conglomerate bars up to 5 m thick and 40 to 50 m across. The tops of these bars are covered with storm-formed symmetric conglomeratic dunes. Data suggest that four major environments (fluvial, beach, offshore conglomerate bars, and offshore graded storm conglomerates) should be identifiable and predictable in the subsurface. (JMT)

  13. Equivalent Fractions

    NSDL National Science Digital Library

    Miss Ogle

    2012-04-05

    What is an equivalent fraction? Students, I want you to create song about fractions. Here is a fraction song video to help you get and idea. Remember your song should be at least five sentences long. Math Song- Equivalent Fractions Students, I want you to click on the website below and the play the fraction game. Let's see how many ...

  14. Matching Derived Functionally-Same Stimulus Relations: Equivalence-Equivalence and Classical Analogies

    ERIC Educational Resources Information Center

    Carpentier, Franck; Smeets, Paul M.; Barnes-Holmes, Dermot; Stewart, Ian

    2004-01-01

    Previous studies have shown that, after being trained on A-B and A-C matching tasks, subjects match not only functionally-same B and C stimuli (stimulus equivalence), but also BC compounds with same-class elements and BC compounds with different-class elements (equivalence-equivalence). Similar performances are required in classical analogies (a :…

  15. Trapping Coyotes 

    E-print Network

    Texas Wildlife Services

    2008-04-15

    to livestock and crops in Texas. Damage Coyotes normally kill livestock by biting them around the throat. To determine if an ani- L-1908 4-08 mal has been killed by a coyote, carefully peel back the skin around the throat and look for tooth puncture wounds.... It is important that traps be kept clean and in good working condition. New traps have a thin coatingofgreaseandmustbecleanedbeforeuse. Boilinginwaterorsettingthetrapsouttoweath- er is usually sufficient to remove the grease. Old traps should be periodically...

  16. Optical trapping

    PubMed Central

    Neuman, Keir C.; Block, Steven M.

    2006-01-01

    Since their invention just over 20 years ago, optical traps have emerged as a powerful tool with broad-reaching applications in biology and physics. Capabilities have evolved from simple manipulation to the application of calibrated forces on—and the measurement of nanometer-level displacements of—optically trapped objects. We review progress in the development of optical trapping apparatus, including instrument design considerations, position detection schemes and calibration techniques, with an emphasis on recent advances. We conclude with a brief summary of innovative optical trapping configurations and applications. PMID:16878180

  17. Involute, minimal, outer, and increasingly trapped spheres

    SciTech Connect

    Hayward, Sean A. [Center for Astrophysics, Shanghai Normal University, 100 Guilin Road, Shanghai 200234 (China)

    2010-01-15

    Seven different refinements of trapped surfaces are proposed, each intended as potential stability conditions. This article concerns spherical symmetry, but each condition can be generalized. Involute trapped spheres satisfy a similar condition to minimal trapped spheres, which are strictly minimal with respect to the Kodama vector. There is also a weaker version of involute trapped spheres. Outer trapped spheres have positive surface gravity. Increasingly (future, respectively, past) trapped spheres generate spheres which are more trapped in a (future, respectively, past) causal direction, with three types: in any such causal direction, along the dual Kodama vector, and in some such causal direction. Assuming the null energy condition, the seven conditions form a strict hierarchy, in the above order. In static space-times, they reduce to three inequivalent definitions, namely, minimal, outer, and increasingly trapped spheres. For a widely considered class of so-called nice (or nondirty) black holes, minimal trapped and outer trapped become equivalent. Reissner-Nordstroem black holes provide examples of this, and that the increasingly trapped differs. Examples where all three refinements differ are provided by a simple family of dirty black holes parametrized by mass and singularity area.

  18. Salisbury hospital's steam trap success.

    PubMed

    Baillie, Jonathan

    2011-03-01

    With the Carbon Reduction Commitment now fully in force, and the NHS tasked with achieving tough carbon emission reduction targets in line with both UK and EU mandates, healthcare estates teams across the country are seeking cost-effective ways to reduce energy consumption. Against this backdrop, Salisbury District Hospital has implemented a concerted energy-saving programme, key elements of which include replacing existing bucket steam traps with higher performing, lower maintenance, and more effective GEM venturi steam traps from Thermal Energy International (TEI), installing a new gas CHP engine, and looking into fitting a TEI condensate economiser system. PMID:21485315

  19. PATHOGEN EQUIVALENCY COMMITTEE UPDATE: PFRP EQUIVALENCY DETERMINATIONS

    EPA Science Inventory

    This presentation will: Review the mandate of the Pathogen Equivalency Committee Review the PEC's current membership of 10 Discuss how a typical application is evaluated Note where information can be found List present deliberations/applications and describe t...

  20. Equivalence principles and electromagnetism

    NASA Technical Reports Server (NTRS)

    Ni, W.-T.

    1977-01-01

    The implications of the weak equivalence principles are investigated in detail for electromagnetic systems in a general framework. In particular, it is shown that the universality of free-fall trajectories (Galileo weak equivalence principle) does not imply the validity of the Einstein equivalence principle. However, the Galileo principle plus the universality of free-fall rotation states does imply the Einstein principle.

  1. Hot Ideas. Equivalence

    ERIC Educational Resources Information Center

    Bobis, Janette

    2005-01-01

    Three activities are presented that are designed to develop an understanding of equivalence. Equivalent fractions have the same value, but may be expressed with a different denominator or different notation. "Decimal Fraction Dominoes" focuses on the equivalence of commonly occurring fractions, decimal fractions, percentages and their pictorial…

  2. Equivalence among hypertopologies

    Microsoft Academic Search

    Lubica Holá; Roberto Lucchetti

    1995-01-01

    We provide equivalent conditions for pairwise coincidence of the (upper parts of the) ball, proximal-ball and Wijsman topologies. Moreover, we provide equivalent conditions for coincidence of a hypertology, given two equivalent distances on the underlying metric space. Finally we show that the ball and proximal-ball topologies are not regular.

  3. Interaction of trapped ions with trapped atoms

    E-print Network

    Grier, Andrew T. (Andrew Todd)

    2011-01-01

    In this thesis, I present results from two Paul-trap based ion traps carried out in the Vuleti? laboratory: the Atom-Ion trap for collision studies between cold atoms and cold ions, and the Cavity-Array trap for studying ...

  4. Identifying Equivalent Fractions

    NSDL National Science Digital Library

    J.C. Banfill

    2007-12-12

    This site helps students understand how to identify equivalent fractions by explaining what equivalent fractions are and how to compare two fractions to see if they are equivalent. There is also a list of fractions equivalent to 1/2, 1/3, 1/4, 1/5, and 2/5 so students can begin to see the pattern that emerges. Finally, the site presents an interactive game in which students can practice by naming the equivalent fraction to a given fraction.

  5. Trapped antihydrogen.

    PubMed

    Andresen, G B; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jonsell, S; Jørgensen, L V; Kurchaninov, L; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; el Nasr, S Seif; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2010-12-01

    Antimatter was first predicted in 1931, by Dirac. Work with high-energy antiparticles is now commonplace, and anti-electrons are used regularly in the medical technique of positron emission tomography scanning. Antihydrogen, the bound state of an antiproton and a positron, has been produced at low energies at CERN (the European Organization for Nuclear Research) since 2002. Antihydrogen is of interest for use in a precision test of nature's fundamental symmetries. The charge conjugation/parity/time reversal (CPT) theorem, a crucial part of the foundation of the standard model of elementary particles and interactions, demands that hydrogen and antihydrogen have the same spectrum. Given the current experimental precision of measurements on the hydrogen atom (about two parts in 10(14) for the frequency of the 1s-to-2s transition), subjecting antihydrogen to rigorous spectroscopic examination would constitute a compelling, model-independent test of CPT. Antihydrogen could also be used to study the gravitational behaviour of antimatter. However, so far experiments have produced antihydrogen that is not confined, precluding detailed study of its structure. Here we demonstrate trapping of antihydrogen atoms. From the interaction of about 10(7) antiprotons and 7?×?10(8) positrons, we observed 38 annihilation events consistent with the controlled release of trapped antihydrogen from our magnetic trap; the measured background is 1.4?±?1.4 events. This result opens the door to precision measurements on anti-atoms, which can soon be subjected to the same techniques as developed for hydrogen. PMID:21085118

  6. Magnetic Trapping

    NSDL National Science Digital Library

    Mendez, J.

    This set of five web pages provides a non-mathematical introduction to the motion of charged particles in magnetic fields. These pages describe the "guiding center motion" which determines the motion of ions and electrons trapped in the Earth's magnetic field and in laboratory plasma devices. Also covered are gyration and mirroring, adiabatic invariance and drifts due to an electric field and gradients in the magnetic field intensity. This is part of the work "The Exploration of the Earth's Magnetosphere". A Spanish translation is available.

  7. Equivalent Fractions Finder

    NSDL National Science Digital Library

    2007-12-12

    This activity allows students to visually experiment with the relationship between the values of equivalent fractions and areas within a square or a circle. The activity provides the user with a fraction, its equivalent representation as a shaded portion of a square or circle, and a number line. Also displayed are two empty squares or circles. The user can add and color sections to the blank shapes to create a fraction equivalent to the computer generated fraction.

  8. Multiple paths in complex tasks

    NASA Technical Reports Server (NTRS)

    Galanter, Eugene; Wiegand, Thomas; Mark, Gloria

    1987-01-01

    The relationship between utility judgments of subtask paths and the utility of the task as a whole was examined. The convergent validation procedure is based on the assumption that measurements of the same quantity done with different methods should covary. The utility measures of the subtasks were obtained during the performance of an aircraft flight controller navigation task. Analyses helped decide among various models of subtask utility combination, whether the utility ratings of subtask paths predict the whole tasks utility rating, and indirectly, whether judgmental models need to include the equivalent of cognitive noise.

  9. Active microwave water equivalence

    NASA Technical Reports Server (NTRS)

    Boyne, H. S.; Ellerbruch, D. A.

    1980-01-01

    Measurements of water equivalence using an active FM-CW microwave system were conducted over the past three years at various sites in Colorado, Wyoming, and California. The measurement method is described. Measurements of water equivalence and stratigraphy are compared with ground truth. A comparison of microwave, federal sampler, and snow pillow measurements at three sites in Colorado is described.

  10. Time dependence of trapping and detrapping of particles by saturable traps

    NASA Astrophysics Data System (ADS)

    Richards, Peter M.

    1990-02-01

    The rate for trapping and detrapping of particles diffusing to saturable traps is investigated. Careful attention is paid to the fact that, for traps which can hold only one particle, the trap occupation pT must be regarded as a stochastic rather than continuous variable. It is shown that neglecting correlation between pT and the occupation p1 of particles in the trap's neighborhood can lead to serious errors when the reaction is diffusion limited. However, an average correlation (AC) approximation, which is justified on the basis of detailed consideration of the hopping equations, is shown to be reliable in all cases. The AC is further shown to be equivalent to the McNabb-Foster equations, previously derived by heuristic arguments only, in the continuum limit. Short time effects are predicted in the diffusion-limited regime which result from the discreteness of the lattice. Results of the theory are supported by good agreement with Monte Carlo simulation data.

  11. Neutron dose equivalent meter

    DOEpatents

    Olsher, Richard H. (Los Alamos, NM); Hsu, Hsiao-Hua (Los Alamos, NM); Casson, William H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM); Kleck, Jeffrey H. (Menlo Park, CA); Beverding, Anthony (Foster City, CA)

    1996-01-01

    A neutron dose equivalent detector for measuring neutron dose capable of accurately responding to neutron energies according to published fluence to dose curves. The neutron dose equivalent meter has an inner sphere of polyethylene, with a middle shell overlying the inner sphere, the middle shell comprising RTV.RTM. silicone (organosiloxane) loaded with boron. An outer shell overlies the middle shell and comprises polyethylene loaded with tungsten. The neutron dose equivalent meter defines a channel through the outer shell, the middle shell, and the inner sphere for accepting a neutron counter tube. The outer shell is loaded with tungsten to provide neutron generation, increasing the neutron dose equivalent meter's response sensitivity above 8 MeV.

  12. Migraine equivalents in childhood.

    PubMed

    Teixeira, Karine C S; Montenegro, Maria Augusta; Guerreiro, Marilisa M

    2014-10-01

    Migraine equivalents are a group of periodic and paroxysmal neurologic diseases. Because headache is not a prominent symptom, the diagnosis might be challenging. The objective of the study was to evaluate the frequency and outcome of migraine equivalents. This was a retrospective study. We included benign paroxysmal torticollis of infancy, benign paroxysmal vertigo of infancy, abdominal migraine, cyclic vomiting, aura without migraine, and confusional migraine. We evaluated the frequency of events, treatment, and outcome. Out of 674 children with headache, 38 (5.6%) presented with migraine equivalents. Twenty-one were boys and the mean age was 6.1 years. Fifteen had abdominal migraine, 12 benign paroxysmal vertigo, 5 confusional migraine, 3 aura without migraine, 2 paroxysmal torticollis, and 1 cyclic vomiting. Prophylactic treatment was introduced in 23 patients; 4 lost follow-up and 19 had significant improvement. We conclude that the correct diagnosis of migraine equivalents enables an effective treatment with an excellent outcome. PMID:24092892

  13. Teach Measurement Equivalencies Simply.

    ERIC Educational Resources Information Center

    Koons, Theresa L.

    1984-01-01

    A system of teaching measurement equivalencies to students with learning disabilities promotes understanding by teaching basic measurement language. Concrete objects are used to develop the association between a measurement term and its size. (CL)

  14. Multiscale shape equivalence

    NASA Astrophysics Data System (ADS)

    Forte, Peter; Greenhill, Darrel

    1996-09-01

    In this paper we define a property applied to contours and 2D shapes we call `shape equivalence', or more strictly, `virtual shape equivalence'. The intuitive idea is that two contours or 2D shapes are `virtually equivalent' (at a given scale of resolution) if they can possibly give rise to identical area sampled images (at the given scale) with respect to a given sampling regime. The word `virtual' is used because the relationship is not a true equivalence relation--in particular it is not strictly transitive. The idea is similar to the psychological notion of `just noticeable difference' (JND). Two stimuli are within a JND threshold if a subject cannot perceptually distinguish them, even though they may in fact be different. Similarly our notion of virtual equivalence of contours corresponds to there being no noticeable difference between them with respect to a certain class of sampling regimes at a particular scale of resolution. The usefulness of the concept is that it can be used to built a formal theory of shape and contour simplification (at various scales) to assist object recognition.

  15. Equivalent Fractions Pointer

    NSDL National Science Digital Library

    2010-01-01

    In this activity, students highlight portions of circles or squares that are equivalent to a given fraction. As the student highlights sections, a pointer on a number line between zero and one updates so they can see when they are close or equal to the given fraction. This activity allows students to explore equivalent fractions by making it necessary that each of the three fractions have a different denominator but have the fractions be equal. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.

  16. Inductive Reasoning in Zambia, Turkey, and the Netherlands Establishing Cross-Cultural Equivalence.

    ERIC Educational Resources Information Center

    van de Vijver, Fons J. R.

    2002-01-01

    Administered tasks of inductive reasoning to 704 Zambian, 877 Turkish, and 632 Dutch students from the highest 2 grades of primary and the lowest 2 grades of secondary school. Results show strong evidence for structural equivalence and partial evidence for measurement unit equivalence, but did not support full score equivalence. (SLD)

  17. Free products, Orbit Equivalence and Measure Equivalence Rigidity

    E-print Network

    Paris-Sud XI, Université de

    Free products, Orbit Equivalence and Measure Equivalence Rigidity Aur´elien Alvarez and Damien Gaboriau February 18, 2009 Abstract We study the analogue in orbit equivalence of free product decomposition and free indecomposability for countable groups. We introduce the (orbit equivalence invariant

  18. Everyday Mathematics Equivalent Fractions

    NSDL National Science Digital Library

    2011-02-03

    This iOS app ($) provides students with practice and reinforcement of fraction concepts in a solitaire context. Users try to clear a board by matching cards displaying equivalent visual and numeric representations of fractions, while getting feedback and scoring points for accuracy. A tutorial with voice explains how to play.

  19. PATHOGEN EQUIVALENCY COMMITTEE (PEC)

    EPA Science Inventory

    The U.S. Environmental Protection Agency created the PEC in 1985 to make recommendations to EPA and State managers on the equivalency of unproven sewage sludge disinfection technologies/processes to either a Process to Significantly Reduce Pathogens (PSRP) or a Process to Further...

  20. Five Equivalent d Orbitals

    ERIC Educational Resources Information Center

    Pauling, Linus; McClure, Vance

    1970-01-01

    Amplifies and clarifies a previous paper on pyramidal d orbitals. Discusses two sets of pyramid d orbitals with respect to their maximum bond strength and their symmetry. Authors described the oblate and prolate pentagonal antiprisms arising from the two sets of five equivalent d orbitals. (RR)

  1. Superconducting microfabricated ion traps

    E-print Network

    Wang, Shannon Xuanyue

    We fabricate superconducting ion traps with niobium and niobium nitride and trap single [superscript 88]Sr ions at cryogenic temperatures. The superconducting transition is verified and characterized by measuring the ...

  2. A Better Fly Trap

    NSDL National Science Digital Library

    Lawrence Hall of Science

    1979-01-01

    In this activity, learners observe fly behavior and then build a flytrap. They make more observations, compare the effectiveness of different traps, and modify their traps to increase their effectiveness. In doing so, learners consider what variables make for an effective trap as well as learning how to study the behavior of an animal. Even pesky flies provide an interesting challenge.

  3. Derived Equivalences by Quantization

    Microsoft Academic Search

    Dmitry Kaledin

    2008-01-01

    We assume given a smooth symplectic (in the algebraic sense) resolution $X$\\u000aof an affine algebraic variety $Y$, and we prove that, possibly after replacing\\u000a$Y$ with an etale neighborhood of a point, the derived category of coherent\\u000asheaves on $X$ is equivalent to the dervied category of finitely generated left\\u000amodules over a non-commutative algebra $R$, a non-commutative resolution

  4. Thin, light-trapping silicon solar cells for space

    Microsoft Academic Search

    Geoffrey A. Landis

    1988-01-01

    Ultrathin silicon solar cells with high efficiency and radiation tolerance can be made by incorporating light-trapping and heterojunction surface passivation. Calculations show that a 2 mu m-thick light-trapping cell remains over 18% efficient after the equivalent of 20 years in geosynchronous orbit. Including a 50 mu m coverglass, the thin cells had, after irradiation, a specific power over ten times

  5. Thin, light-trapping silicon solar cells for space

    Microsoft Academic Search

    Geoffrey A. Landis

    1988-01-01

    Ultrathin silicon solar cells with high efficiency and radiation tolerance can be made by incorporating light-trapping and heterojunction surface passivation. Calculations show that a 2-micron-thick light-trapping cell remains over 18 percent efficient after the equivalent of 20 years in geosynchronous orbit. Including a 50-micron coverglass, the thin cells had, after irradiation, a specific power over ten times higher than that

  6. Big brains are not enough: performance of three parrot species in the trap-tube paradigm.

    PubMed

    Liedtke, Jannis; Werdenich, Dagmar; Gajdon, Gyula K; Huber, Ludwig; Wanker, Ralf

    2011-01-01

    The trap-tube task has become a benchmark test for investigating physical causality in vertebrates. In this task, subjects have to retrieve food out of a horizontal tube using a tool and avoiding a trap hole in the tube. Great apes and corvids succeeded in this task. Parrots with relative brain volumes comparable to those of corvids and primates also demonstrate high cognitive abilities. We therefore tested macaws, a cockatoo, and keas on the trap-tube paradigm. All nine parrots failed to solve the task. In a simplified task, trap tubes with a slot inserted along the top were offered. The slot allowed the birds to move the reward directly with their bills. All but one individual solved this task by lifting the food over the trap. However, the parrots failed again when they were prevented from lifting the reward, although they anticipated that food will be lost when moved into the trap. We do not think that the demanding use of an external object is the main reason for the parrots' failure. Moreover, we suppose these parrots fail to consider the trap's position in the beginning of a trial and were not able to stop their behaviour and move the reward in the trap's opposite direction. PMID:20814805

  7. Trap style influences wild pig behavior and trapping success

    USGS Publications Warehouse

    Williams, B.L.; Holtfreter, R.W.; Ditchkoff, S.S.; Grand, J.B.

    2011-01-01

    Despite the efforts of many natural resource professionals, wild pig (Sus scrofa) populations are expanding in many areas of the world. Although many creative techniques for controlling pig populations are being explored, trapping has been and still is themost commonly usedmethod of population control formany public and private land managers. We conducted an observational study to examine the efficiency of 2 frequently used trap styles: a small, portable box-style trap and a larger, semi-permanent, corral-style trap.We used game cameras to examine patterns of trap entry by wild pigs around each style of trap, and we conducted a trapping session to compare trapping success between trap styles. Adult female and juvenile wild pigs entered both styles of trap more readily than did adult males, and adult males seemed particularly averse to entering box traps. Less than 10% of adult male visits to box traps resulted in entries, easily the least percentage of any class at any style of trap. Adult females entered corral traps approximately 2.2 times more often per visit than box traps and re-entered corral traps >2 times more frequently. Juveniles entered and reentered both box and corral traps at similar rates. Overall (all-class) entry-per-visit rates at corral traps (0.71) were nearly double that of box traps (0.37). Subsequent trapping data supported these preliminary entry data; the capture rate for corral traps was >4 times that of box traps. Our data suggest that corral traps are temporally and economically superior to box traps with respect to efficiency; that is, corral traps effectively trap more pigs per trap night at a lower cost per pig than do box traps. ?? 2011 The Wildlife Society.

  8. Strong shift equivalence theory and the shift equivalence problem

    Microsoft Academic Search

    J. B. WAGONER

    1999-01-01

    This paper discusses strong shift equivalence and counterexamples to the long standing Shift Equivalence Problem in symbolic dynamics. We also discuss how strong shift equivalence theory is closely related to areas of mathematics outside dynamics such as algebraic K-theory, cyclic homology, and topological quantum eld theory.

  9. Process of task analysis

    Microsoft Academic Search

    H. S. Blackman; D. I. Gertman; L. N. Haney

    1985-01-01

    The paper presents a task analysis form for the organization of task analysis efforts. In terms of the form, task descriptions for use in task analysis data collection are given, and detailed definitions of 35 task analysis categories are offered. The categories include important aspects of task performance, consequences, and feedback, as well as aspects of training and knowledge requirements.

  10. Trapping effects on inflation

    E-print Network

    Wolung Lee; Kin-Wang Ng; I-Chin Wang; Chun-Hsien Wu

    2011-08-23

    We develop a Lagrangian approach based on the influence functional method so as to derive self-consistently the Langevin equation for the inflaton field in the presence of trapping points along the inflaton trajectory. The Langevin equation exhibits the backreaction and the fluctuation-dissipation relation of the trapping. The fluctuation is induced by a multiplicative colored noise that can be identified as the the particle number density fluctuations and the dissipation is a new effect that may play a role in the trapping with a strong coupling. In the weak coupling regime, we calculate the power spectrum of the noise-driven inflaton fluctuations for a single trapping point and studied its variation with the trapping location. We also consider a case with closely spaced trapping points and find that the resulting power spectrum is blue.

  11. Language Equivalence for Probabilistic Automata

    E-print Network

    Ouaknine, Joël

    on the complexity of these algorithms, accounting for the differences in performance. 1 Introduction Probabilistic to verify contextual equivalence of probabilistic programs3 , which in turn can be used to express a broad, the translation relates (probabilistic) contextual equivalence with (probabilistic) language equivalence [14

  12. Neutral atom traps.

    SciTech Connect

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  13. The Equivalence Principle Revisited

    E-print Network

    R. Aldrovandi; P. B. Barros; J. G. Pereira

    2002-12-07

    A precise formulation of the strong Equivalence Principle is essential to the understanding of the relationship between gravitation and quantum mechanics. The relevant aspects are reviewed in a context including General Relativity, but allowing for the presence of torsion. For the sake of brevity, a concise statement is proposed for the Principle: "An ideal observer immersed in a gravitational field can choose a reference frame in which gravitation goes unnoticed". This statement is given a clear mathematical meaning through an accurate discussion of its terms. It holds for ideal observers (time-like smooth non-intersecting curves), but not for real, spatially extended observers. Analogous results hold for gauge fields. The difference between gravitation and the other fundamental interactions comes from their distinct roles in the equation of force.

  14. [Generalization of money-handling though training in equivalence relationships].

    PubMed

    Vives-Montero, Carmen; Valero-Aguayo, Luis; Ascanio, Lourdes

    2011-02-01

    This research used a matching-to-sample procedure and equivalence learning process with language and verbal tasks. In the study, an application of the equivalence relationship of money was used with several kinds of euro coins presented. The sample consisted of 16 children (8 in the experimental group and 8 in the control group) aged 5 years. The prerequisite behaviors, the identification of coins and the practical use of different euro coins, were assessed in the pre and post phases for both groups. The children in the experimental group performed an equivalence task using the matching-to-sample procedure. This consisted of a stimulus sample and four matching stimuli, using a series of euro coins with equivalent value in each set. The children in the control group did not undergo this training process. The results showed a large variability in the children's data of the equivalence tests. The experimental group showed the greatest pre and post changes in the statistically significant data. They also showed a greater generalization in the identification of money and in the use of euro coins than the control group. The implications for educational training and the characteristics of the procedure used here for coin equivalence are discussed. PMID:21266139

  15. The transfer of Cfunc contextual control through equivalence relations.

    PubMed

    Perez, William F; Fidalgo, Adriana P; Kovac, Roberta; Nico, Yara C

    2015-05-01

    Derived relational responding is affected by contextual stimuli (Cfunc) that select specific stimulus functions. The present study investigated the transfer of Cfunc contextual control through equivalence relations by evaluating both (a) the maintenance of Cfunc contextual control after the expansion of a relational network, and (b) the establishment of novel contextual stimuli by the transfer of Cfunc contextual control through equivalence relations. Initially, equivalence relations were established and contingencies were arranged so that colors functioned as Cfunc stimuli controlling participants' key-pressing responses in the presence of any stimulus from a three-member equivalence network. To investigate the first research question, the three-member equivalence relations were expanded to five members and the novel members were presented with the Cfunc stimuli in the key-pressing task. To address the second goal of this study, the colors (Cfunc) were established as equivalent to certain line patterns. The transfer of contextual cue function (Cfunc) was tested replacing the colored backgrounds with line patterns in the key-pressing task. Results suggest that the Cfunc contextual control was transferred to novel stimuli that were added to the relational network. In addition, the line patterns indirectly acquired the contextual cue function (Cfunc) initially established for the colored backgrounds. The conceptual and applied implications of Cfunc contextual control are discussed. PMID:25892218

  16. Search for trapped antihydrogen

    NASA Astrophysics Data System (ADS)

    Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Bowe, P. D.; Bray, C. C.; Butler, E.; Cesar, C. L.; Chapman, S.; Charlton, M.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Hangst, J. S.; Hardy, W. N.; Hayano, R. S.; Hayden, M. E.; Humphries, A. J.; Hydomako, R.; Jonsell, S.; Jørgensen, L. V.; Kurchaninov, L.; Lambo, R.; Madsen, N.; Menary, S.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; Seif El Nasr, S.; Silveira, D. M.; So, C.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wilding, D.; Wurtele, J. S.; Yamazaki, Y.; Alpha Collaboration

    2011-01-01

    We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ?30 ms. After a three-week experimental run in 2009 involving mixing of 10 7 antiprotons with 1.3×10 positrons to produce 6×10 antihydrogen atoms, we have identified six antiproton annihilation events that are consistent with the release of trapped antihydrogen. The cosmic ray background, estimated to contribute 0.14 counts, is incompatible with this observation at a significance of 5.6 sigma. Extensive simulations predict that an alternative source of annihilations, the escape of mirror-trapped antiprotons, is highly unlikely, though this possibility has not yet been ruled out experimentally.

  17. Nuclear Physics with trapped

    E-print Network

    Boas, Harold P.

    Outline · Scope and applications of nuclear physics precision frontier compliments LHC properties and therapeutic medicine · "Cool" tools ­ atom traps probing fundamental symmetries (ion traps) trace analysis The precision frontier probes similar physics compared to colliders; is a complementary and important cross

  18. Search For Trapped Antihydrogen

    E-print Network

    Gorm B. Andresen; Mohammad D. Ashkezari; Marcelo Baquero-Ruiz; William Bertsche; Paul D. Bowe; Crystal C. Bray; Eoin Butler; Claudio L. Cesar; Steven Chapman; Michael Charlton; Joel Fajans; Tim Friesen; Makoto C. Fujiwara; David R. Gill; Jeffrey S. Hangst; Walter N. Hardy; Ryugo S. Hayano; Michael E. Hayden; Andrew J. Humphries; Richard Hydomako; Svante Jonsell; Lars V. J\\orgensen; Lenoid Kurchaninov; Ricardo Lambo; Niels Madsen; Scott Menary; Paul Nolan; Konstantin Olchanski; Art Olin; Alexander Povilus; Petteri Pusa; Francis Robicheaux; Eli Sarid; Sarah Seif El Nasr; Daniel M. Silveira; Chukman So; James W. Storey; Robert I. Thompson; Dirk P. van der Werf; Dean Wilding; Jonathan S. Wurtele; Yasunori Yamazaki

    2010-12-18

    We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ~30 ms. After a three-week experimental run in 2009 involving mixing of 10^7 antiprotons with 1.3 10^9 positrons to produce 6 10^5 antihydrogen atoms, we have identified six antiproton annihilation events that are consistent with the release of trapped antihydrogen. The cosmic ray background, estimated to contribute 0.14 counts, is incompatible with this observation at a significance of 5.6 sigma. Extensive simulations predict that an alternative source of annihilations, the escape of mirror-trapped antiprotons, is highly unlikely, though this possibility has not yet been ruled out experimentally.

  19. Buffer strips trap contaminants

    E-print Network

    Nebraska-Lincoln, University of

    ideal width for riparian buffer strips in Midwest. They trap sediment, nutrients and pesticides. That maater Buffer strips trap contaminants Three research and demonstration projects seek to determine kes riparian buffer strips a valuable tool in preventing nonpo int sour ce pollution, according

  20. Magnetic trapping of neutrons

    PubMed

    Huffman; Brome; Butterworth; Coakley; Dewey; Dzhosyuk; Golub; Greene; Habicht; Lamoreaux; Mattoni; McKinsey; Wietfeldt; Doyle

    2000-01-01

    Accurate measurement of the lifetime of the neutron (which is unstable to beta decay) is important for understanding the weak nuclear force and the creation of matter during the Big Bang. Previous measurements of the neutron lifetime have mainly been limited by certain systematic errors; however, these could in principle be avoided by performing measurements on neutrons stored in a magnetic trap. Neutral-particle and charged-particle traps are widely used for studying both composite and elementary particles, because they allow long interaction times and isolation of particles from perturbing environments. Here we report the magnetic trapping of neutrons. The trapping region is filled with superfluid 4He, which is used to load neutrons into the trap and as a scintillator to detect their decay. Neutrons in the trap have a lifetime of 750(+330)(-200) seconds, mainly limited by their beta decay rather than trap losses. Our experiment verifies theoretical predictions regarding the loading process and magnetic trapping of neutrons. Further refinement of this method should lead to improved precision in the neutron lifetime measurement. PMID:10638750

  1. Optical Trapping of Nanoparticles

    PubMed Central

    Bergeron, Jarrah; Zehtabi-Oskuie, Ana; Ghaffari, Saeedeh; Pang, Yuanjie; Gordon, Reuven

    2013-01-01

    Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping and manipulating small biological particles. Ashkin and co-workers first demonstrated optical tweezers using a single focused beam1. The single beam trap can be described accurately using the perturbative gradient force formulation in the case of small Rayleigh regime particles1. In the perturbative regime, the optical power required for trapping a particle scales as the inverse fourth power of the particle size. High optical powers can damage dielectric particles and cause heating. For instance, trapped latex spheres of 109 nm in diameter were destroyed by a 15 mW beam in 25 sec1, which has serious implications for biological matter2,3. A self-induced back-action (SIBA) optical trapping was proposed to trap 50 nm polystyrene spheres in the non-perturbative regime4. In a non-perturbative regime, even a small particle with little permittivity contrast to the background can influence significantly the ambient electromagnetic field and induce a large optical force. As a particle enters an illuminated aperture, light transmission increases dramatically because of dielectric loading. If the particle attempts to leave the aperture, decreased transmission causes a change in momentum outwards from the hole and, by Newton's Third Law, results in a force on the particle inwards into the hole, trapping the particle. The light transmission can be monitored; hence, the trap can become a sensor. The SIBA trapping technique can be further improved by using a double-nanohole structure. The double-nanohole structure has been shown to give a strong local field enhancement5,6. Between the two sharp tips of the double-nanohole, a small particle can cause a large change in optical transmission, thereby inducing a large optical force. As a result, smaller nanoparticles can be trapped, such as 12 nm silicate spheres7 and 3.4 nm hydrodynamic radius bovine serum albumin proteins8. In this work, the experimental configuration used for nanoparticle trapping is outlined. First, we detail the assembly of the trapping setup which is based on a Thorlabs Optical Tweezer Kit. Next, we explain the nanofabrication procedure of the double-nanohole in a metal film, the fabrication of the microfluidic chamber and the sample preparation. Finally, we detail the data acquisition procedure and provide typical results for trapping 20 nm polystyrene nanospheres. PMID:23354173

  2. Deuterium trapping in tungsten

    NASA Astrophysics Data System (ADS)

    Poon, Michael

    Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation. Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies. Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation. The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D2 molecules inside the void with a trap energy of 1.2 eV. Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D irradiation. Deuterium trapping could be characterized by three regimes: (i) enhanced D retention in a graphitic film formed by the C+ irradiation; (ii) decreased D retention in a modified tungsten-carbon layer; and (iii) D retention in pure tungsten.

  3. Optically programmable excitonic traps.

    PubMed

    Alloing, Mathieu; Lemaître, Aristide; Galopin, Elisabeth; Dubin, François

    2013-01-01

    With atomic systems, optically programmed trapping potentials have led to remarkable progress in quantum optics and quantum information science. Programmable trapping potentials could have a similar impact on studies of semiconductor quasi-particles, particularly excitons. However, engineering such potentials inside a semiconductor heterostructure remains an outstanding challenge and optical techniques have not yet achieved a high degree of control. Here, we synthesize optically programmable trapping potentials for indirect excitons of bilayer heterostructures. Our approach relies on the injection and spatial patterning of charges trapped in a field-effect device. We thereby imprint in-situ and on-demand electrostatic traps into which we optically inject cold and dense ensembles of excitons. This technique creates new opportunities to improve state-of-the-art technologies for the study of collective quantum behavior of excitons and also for the functionalisation of emerging exciton-based opto-electronic circuits. PMID:23546532

  4. Stochastic PAC models for vacancy motions with trapping and detrapping

    NASA Astrophysics Data System (ADS)

    Evenson, William E.; Lu, Jun; Winz, Michele W.; Gardner, John A.; Zacate, Matthew O.; Lee, Teresa; Mommer, Niels

    1999-09-01

    In order to explain PAC data for tetragonal zirconia at temperatures between 900 and 1300ºC, we have developed a four-state stochastic model. The model simulates vacancies which trap and detrap at a PAC probe nucleus. While trapped, the vacancies hop around the probe in equivalent sites. The four states in this Winkler-Gerdau stochastic theory are three trapped states with equivalent electric field gradients (EFGs) of different orientations and a detrapped state with a weaker EFG whose axis of symmetry is oriented along the diagonal between the three trapped EFGs. There are three hopping rates in this model: w, the rate a trapped vacancy hops around the probe, wD, the detrapping rate, and wt, the trapping rate. We report results of calculations for values of these hopping rates implied by our tetragonal zirconia data, and we report heuristic fitting functions which summarize the computer results and can be used to fit data efficiently for a wide range of parameters.

  5. Holographic optical trapping.

    PubMed

    Grier, David G; Roichman, Yael

    2006-02-10

    Holographic optical tweezers use computer-generated holograms to create arbitrary three-dimensional configurations of single-beam optical traps that are useful for capturing, moving, and transforming mesoscopic objects. Through a combination of beam-splitting, mode-forming, and adaptive wavefront correction, holographic traps can exert precisely specified and characterized forces and torques on objects ranging in size from a few nanometers to hundreds of micrometers. Offering nanometer-scale spatial resolution and real-time reconfigurability, holographic optical traps provide unsurpassed access to the microscopic world and have found applications in fundamental research, manufacturing, and materials processing. PMID:16512529

  6. Holographic optical trapping

    SciTech Connect

    Grier, David G.; Roichman, Yael

    2006-02-10

    Holographic optical tweezers use computer-generated holograms to create arbitrary three-dimensional configurations of single-beam optical traps that are useful for capturing, moving, and transforming mesoscopic objects. Through a combination of beam-splitting, mode-forming, and adaptive wavefront correction, holographic traps can exert precisely specified and characterized forces and torques on objects ranging in size from a few nanometers to hundreds of micrometers. Offering nanometer-scale spatial resolution and real-time reconfigurability, holographic optical traps provide unsurpassed access to the microscopic world and have found applications in fundamental research, manufacturing, and materials processing.

  7. Trapping of Free Electrons in Multipole System

    NASA Astrophysics Data System (ADS)

    Mahdavi, Mohammad; Khodadadi Azadboni, Fatemeh; Khodadadi Azadboni, Reza

    2012-08-01

    In this paper, the effective Parameters in the confinement and trapping of fast electrons in plasma source Such as; plasma pressure, wall material of plasma chamber and magnetic mirror rate have been investigated with using Comsol & Geant4 code. The calculations are shown that the Multicusp magnetic field was effective the pressure less than 5 mTor, and the confinement effect becomes stronger with decreasing pressure. It is equivalent to a higher yield of output ions of plasma source. The number of fast electrons trapped in the magnetic field increases with increasing magnetic field intensity and using aluminum for wall material. Optimum conditions of confinement plasma, leading to increased the hot electron density, and ionization efficiency is increased. The results of investigations have demonstrated good correspondence with theoretical calculations, therefore there is the adequacy of the developed approach and the possibility to build more effective source ion on this basis.

  8. RADIATION PROTECTION KEYWORDS: equivalent sphere

    E-print Network

    Lin, Zi-wei

    RADIATION PROTECTION KEYWORDS: equivalent sphere model, space radiation, organ dose IMPROVEMENT OF THE EQUIVALENT SPHERE MODEL FOR SPACE RADIATION ENVIRONMENTS Z. W. LIN East Carolina University, Department Accepted for Publication January 21, 2009 In space radiation calculations it is often useful to calculate

  9. Operational Semantics and Program Equivalence

    Microsoft Academic Search

    Andrew M. Pitts

    2000-01-01

    This tutorial paper discusses a particular style of operational semantics that enables one to give a 'syntax-directed' inductive defini- tion of termination which is very useful for reasoning about operational equivalence of programs. We restrict attention to contextual equivalence of expressions in the ML family of programming languages, concentrating on functions involving local state. A brief tour of structural operational

  10. Evaluating Steam Trap Performance 

    E-print Network

    Fuller, N. Y.

    1986-01-01

    Laboratory tests were conducted on several types of steam traps at Holston Defense Corporation in Kingsport, Tennessee. Data from these tests, which determined their relative efficiencies, were used in performing economic analyses to determine...

  11. Multiphoton Magnetooptical Trap

    SciTech Connect

    Wu Saijun; Plisson, Thomas; Brown, Roger C.; Phillips, William D.; Porto, J. V. [Joint Quantum Institute, NIST and University of Maryland, Gaithersburg, Maryland 20899 (United States)

    2009-10-23

    We demonstrate a magnetooptical trap (MOT) configuration which employs optical forces due to light scattering between electronically excited states of the atom. With the standard MOT laser beams propagating along the x and y directions, the laser beams along the z direction are at a different wavelength that couples two sets of excited states. We demonstrate efficient cooling and trapping of cesium atoms in a vapor cell and sub-Doppler cooling on both the red and blue sides of the two-photon resonance. The technique demonstrated in this work may have applications in background-free detection of trapped atoms, and in assisting laser cooling and trapping of certain atomic species that require cooling lasers at inconvenient wavelengths.

  12. Venus fly trap

    NSDL National Science Digital Library

    Paul Lenz (None; )

    2006-01-26

    Time-lapse photos or video show progressions from the start of an event to the end of the event. These time-lapse photos illustrate the growth of a single Venus fly trap. Biological processes require time.

  13. Steam Trap Application 

    E-print Network

    Murphy, J. J.

    1982-01-01

    configuration between the steam user and trap inlet. Most applications are of the gravity drainage type. To facilitate proper trap opera tion and system protection, certain guidelines should be followed. Some equipment designs require syphon and/or lift.... Production/or Process (a) Steam heating a liquid,indirectly (b) Steam heating a gas, indirectly (c) Steam heating a solid or slurry,indirect ly (d) Steam heating a solid, directly 2. Protection (a) Steam line drip (b) Steam Tracing Process...

  14. Undergraduate Students' Understanding of the Contraposition Equivalence Rule in Symbolic and Verbal Contexts

    ERIC Educational Resources Information Center

    Stylianides, Andreas J.; Stylianides, Gabriel J.; Philippou, George N.

    2004-01-01

    Literature suggests that the type of context wherein a task is placed relates to students' performance and solution strategies. In the particular domain of logical thinking, there is the belief that students have less difficulty reasoning in verbal than in logically equivalent symbolic tasks. Thus far, this belief has remained relatively…

  15. Using Stimulus Equivalence Procedures to Teach Relationships between English and Spanish Words.

    ERIC Educational Resources Information Center

    Joyce, Bonnie G.; And Others

    1993-01-01

    A stimulus equivalence procedure for the acquisition of English and Spanish words was evaluated with two adolescents having head injuries. Following training on one task, subjects attained and maintained high scores on all matching-to-sample tasks. Results suggest the procedure is effective for teaching foreign language skills to head-injured…

  16. Search For Trapped Antihydrogen

    E-print Network

    Andresen, Gorm B; Baquero-Ruiz, Marcelo; Bertsche, William; Bowe, Paul D; Bray, Crystal C; Butler, Eoin; Cesar, Claudio L; Chapman, Steven; Charlton, Michael; Fajans, Joel; Friesen, Tim; Fujiwara, Makoto C; Gill, David R; Hangst, Jeffrey S; Hardy, Walter N; Hayano, Ryugo S; Hayden, Michael E; Humphries, Andrew J; Hydomako, Richard; Jonsell, Svante; Jørgensen, Lars V; Kurchaninov, Lenoid; Lambo, Ricardo; Madsen, Niels; Menary, Scott; Nolan, Paul; Olchanski, Konstantin; Olin, Art; Povilus, Alexander; Pusa, Petteri; Robicheaux, Francis; Sarid, Eli; Nasr, Sarah Seif El; Silveira, Daniel M; So, Chukman; Storey, James W; Thompson, Robert I; van der Werf, Dirk P; Wilding, Dean; Wurtele, Jonathan S; Yamazaki, Yasunori

    2011-01-01

    We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ~30 ms. After a three-week experimental run in 2009 involving mixing of 10^7 antiprotons with 1.3 10^9 positrons to produce 6 10^5 antihydrogen atoms, we have identified six antiproton annihilation events that are consist...

  17. Generalized Multiframe Tasks

    Microsoft Academic Search

    Sanjoy K. Baruah; Deji Chen; Sergey Gorinsky; Aloysius K. Mok

    1999-01-01

    A new model for sporadic task systems is introduced. This model—the generalized multiframe task model—further generalizes both the conventional sporadic-tasks model, and the more recent multiframe model of Mok and Chen. A framework for determining feasibility for a wide variety of task systems is established; this framework is applied to this task model to obtain a feasibility-testing algorithm that runs

  18. Equivalency Detectives: Fractions and Decimals!

    NSDL National Science Digital Library

    Maribel Magdaleno

    2012-07-17

    This is a lesson intended to reinforce students' ability to find equivalent fractions and decimals. The lesson requires prior essential vocabulary knowledge, and a basic understanding of converting fractions to decimals and decimals to fractions (specifically tenths and hundredths).

  19. Micro particle launcher/cleaner based on optical trapping technology.

    PubMed

    Liu, Zhihai; Liang, Peibo; Zhang, Yu; Zhang, Yaxun; Zhao, Enming; Yang, Jun; Yuan, Libo

    2015-04-01

    Efficient and controllable launching function of an optical tweezers is a challenging task. We present and demonstrate a novel single fiber optical tweezers which can trap and launch (clean) a target polystyrene (PS) microsphere (diameter~10?m) with independent control by using two wavelengths beams: 980nm and 1480nm. We employ 980nm laser beam to trap the target PS microsphere by molding the fiber tip into a special tapered-shape; and we employ 1480nm laser beam to launch the trapped PS microsphere with a certain velocity by using the thermophoresis force generated from the thermal effect due to the high absorption of the 1480nm laser beams in water. When the launching force is smaller than the trapping force, the PS microsphere will be trapped near the fiber tip, and the launching force will blow away other PS microspheres in the workspace realizing the cleaning function; When the launching force is larger than the trapping force, the trapped PS microsphere will be launched away from the fiber tip with a certain velocity and towards a certain direction, realizing the launching function. The launching velocity, acceleration and the distance can be measured by detecting the interference signals generated from the PS microsphere surface and the fiber tip end-face. This PS microsphere launching and cleaning functions expanded new features of single fiber optical tweezers, providing for the possibility of more practical applications in the micro manipulation research fields. PMID:25968703

  20. Measurement of Trap Length for an Optical Trap

    NASA Technical Reports Server (NTRS)

    Wrbanek, Susan Y.

    2009-01-01

    The trap length along the beam axis for an optical trap formed with an upright, oil-immersion microscope was measured. The goals for this effort were twofold. It was deemed useful to understand the depth to which an optical trap can reach for purposes of developing a tool to assist in the fabrication of miniature devices. Additionally, it was desired to know whether the measured trap length favored one or the other of two competing theories to model an optical trap. The approach was to trap a microsphere of known size and mass and raise it from its initial trap position. The microsphere was then dropped by blocking the laser beam for a pre-determined amount of time. Dropping the microsphere in a free-fall mode from various heights relative to the coverslip provides an estimate of how the trapping length changes with depth in water in a sample chamber on a microscope slide. While it was not possible to measure the trap length with sufficient precision to support any particular theory of optical trap formation, it was possible to find regions where the presence of physical boundaries influenced optical traps, and determine that the trap length, for the apparatus studied, is between 6 and 7 m. These results allow more precise control using optical micromanipulation to assemble miniature devices by providing information about the distance over which an optical trap is effective.

  1. Thermoelectrically cooled water trap

    DOEpatents

    Micheels, Ronald H. (Concord, MA)

    2006-02-21

    A water trap system based on a thermoelectric cooling device is employed to remove a major fraction of the water from air samples, prior to analysis of these samples for chemical composition, by a variety of analytical techniques where water vapor interferes with the measurement process. These analytical techniques include infrared spectroscopy, mass spectrometry, ion mobility spectrometry and gas chromatography. The thermoelectric system for trapping water present in air samples can substantially improve detection sensitivity in these analytical techniques when it is necessary to measure trace analytes with concentrations in the ppm (parts per million) or ppb (parts per billion) partial pressure range. The thermoelectric trap design is compact and amenable to use in a portable gas monitoring instrumentation.

  2. Acoustic bubble traps

    NASA Astrophysics Data System (ADS)

    Geisler, Reinhard; Kurz, Thomas; Lauterborn, Werner

    2000-07-01

    A small, oscillating bubble in a liquid can be trapped in the antinode of an acoustic standing wave field. Bubble stability is required for the study of single bubble sonoluminescence (SBSL). The properties of the acoustic resonator are essential for the stable trapping of sonoluminescing bubbles. Resonators can be chosen according to the intended application: size and geometry can be varied in a wide range. In this work, the acoustic responses of different resonators were measured by means of holographic interferometry, hydrophones and a laser vibrometer. Also, high-speed photography was used to observe the bubble dynamics. Several single, stable sonoluminescent bubbles were trapped simultaneously within an acoustic resonator in the pressure antinodes of a higher harmonic mode (few bubble sonoluminescence, FBSL).

  3. Coherence in Microchip Traps

    E-print Network

    Philipp Treutlein; Peter Hommelhoff; Tilo Steinmetz; Theodor W. Hänsch; Jakob Reichel

    2004-04-22

    We report the coherent manipulation of internal states of neutral atoms in a magnetic microchip trap. Coherence lifetimes exceeding 1 s are observed with atoms at distances of $5-130 \\mu$m from the microchip surface. The coherence lifetime in the chip trap is independent of atom-surface distance within our measurement accuracy, and agrees well with the results of similar measurements in macroscopic magnetic traps. Due to the absence of surface-induced decoherence, a miniaturized atomic clock with a relative stability in the $10^{-13}$ range can be realized. For applications in quantum information processing, we propose to use microwave near-fields in the proximity of chip wires to create potentials that depend on the internal state of the atoms.

  4. Task-specific stability of multifinger steady-state action.

    PubMed

    Reschechtko, Sasha; Zatsiorsky, Vladimir M; Latash, Mark L

    2015-01-01

    The authors explored task-specific stability during accurate multifinger force production tasks with different numbers of instructed fingers. Subjects performed steady-state isometric force production tasks and were instructed not to interfere voluntarily with transient lifting-and-lowering perturbations applied to the index finger. The main results were (a) intertrial variance in the space of finger modes at steady states was larger within the subspace that had no effect on the total force (the uncontrolled manifold [UCM]); (b) perturbations caused large deviations of finger modes within the UCM (motor equivalence); and (c) deviations caused by the perturbation showed larger variance within the UCM. No significant effects of the number of task fingers were noted in any of the 3 indicators. The results are discussed within the frameworks of the UCM and referent configuration hypotheses. The authors conclude, in particular, that all the tasks were effectively 4-finger tasks with different involvement of task and nontask fingers. PMID:25565327

  5. Quantum communication between trapped ions through a dissipative environment

    E-print Network

    H. T. Ng; S. Bose

    2008-05-23

    We study two trapped ions coupled to the axial phonon modes of a one-dimensional Coulomb crystal. This system is formally equivalent to the "two spin-boson" model. We propose a scheme to dynamically generate a maximally entangled state of two ions within a decoherence-free subspace. Here the phononic environment of the trapped ions, whatever its temperature and number of modes, serves as the entangling bus. The efficient production of the pure singlet state can be exploited to perform short-ranged quantum communication which is essential in building up a large-scale quantum computer.

  6. HP Steam Trap Monitoring

    E-print Network

    Pascone, S.

    2011-01-01

    19 7 $74,934.00 Office Building 2 (4 buildings) 3 55 8 $117,202.00 Office Building 3 4 34 16 $206,352.00 Office Building 4 2 12 5 $35,071.00 Office Building 5 4 19 5 $69,412.00 Office Building 6 3 10 3 $22,007.00 Office Building 7 2 18 3 $38...STEAM MONITORING HP Steam Trap Monitoring HP Steam Trap Monitoring ? 12-18 months payback! ? 3-5% permanent reduction in consumption ? LEED Pt.? Innovation in Operations EB O&M ? Saved clients over $1,000,000 Annual consumption...

  7. Many-body fits of phase-equivalent effective interactions

    SciTech Connect

    Johnson, Calvin W. [Department of Physics, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1233 (United States)

    2010-09-15

    In many-body theory, it is often useful to renormalize short-distance, high-momentum components of an interaction via unitary transformations. Such transformations preserve the on-shell physical observables of the two-body system (mostly phase shifts, hence unitarily connected effective interactions are often called phase equivalent) while modifying off-shell T-matrix elements influential in many-body systems. In this paper, I lay out a general and systematic approach for controlling the off-shell behavior of an effective interaction, which can be adjusted to many-body properties, and present an application to trapped fermions at the unitary limit.

  8. Launching Complex Tasks

    ERIC Educational Resources Information Center

    Jackson, Kara J.; Shahan, Emily C.; Gibbons, Lynsey K.; Cobb, Paul A.

    2012-01-01

    Mathematics lessons can take a variety of formats. In this article, the authors discuss lessons organized around complex mathematical tasks. These lessons usually unfold in three phases. First, the task is introduced to students. Second, students work on solving the task. Third, the teacher "orchestrates" a concluding whole-class discussion in…

  9. Equivalent damage: A critical assessment

    NASA Technical Reports Server (NTRS)

    Laflen, J. R.; Cook, T. S.

    1982-01-01

    Concepts in equivalent damage were evaluated to determine their applicability to the life prediction of hot path components of aircraft gas turbine engines. Equivalent damage was defined as being those effects which influence the crack initiation life-time beyond the damage that is measured in uniaxial, fully-reversed sinusoidal and isothermal experiments at low homologous temperatures. Three areas of equivalent damage were examined: mean stress, cumulative damage, and multiaxiality. For each area, a literature survey was conducted to aid in selecting the most appropriate theories. Where possible, data correlations were also used in the evaluation process. A set of criteria was developed for ranking the theories in each equivalent damage regime. These criteria considered aspects of engine utilization as well as the theoretical basis and correlative ability of each theory. In addition, consideration was given to the complex nature of the loading cycle at fatigue critical locations of hot path components; this loading includes non-proportional multiaxial stressing, combined temperature and strain fluctuations, and general creep-fatigue interactions. Through applications of selected equivalent damage theories to some suitable data sets it was found that there is insufficient data to allow specific recommendations of preferred theories for general applications. A series of experiments and areas of further investigations were identified.

  10. Prairie Dog in Trap

    USGS Multimedia Gallery

    A prairie dog trapped outside its burrow in Wind Cave National Park waits for a crew of scientists to arrive. The animal is part of a field test to determine the effectiveness of a USGS-developed oral sylvatic plague vaccine (SPV). This prairie dog will either be brought to a research van for blood ...

  11. Trapped Prairie Dog

    USGS Multimedia Gallery

    A prairie dog trapped outside its burrow in Wind Cave National Park waits for a crew of scientists to arrive. The animal is part of a field test to determine the effectiveness of a USGS-developed oral sylvatic plague vaccine (SPV). This prairie dog will either be brought to a research van for blood ...

  12. Practical axial optical trapping

    NASA Astrophysics Data System (ADS)

    Mack, A. H.; Schlingman, D. J.; Regan, L.; Mochrie, S. G. J.

    2012-10-01

    We describe a new method for calibrating optical trapping measurements in which tension is applied in the direction of the laser beam to a molecule tethered between a surface and an optically trapped bead. Specifically, we present a generally-applicable procedure for converting from the measured scattering intensity and the measured stage displacement to applied tension and bead-coverslip separation, using measurements of the light intensity scattered from an untethered, trapped bead. Our calibration accounts for a number of effects, including aberrations and the interference of forward-reflected bead-scattered light with the trapping beam. To demonstrate the accuracy of our method, we show measurements of the DNA force-versus-extension relation using a range of laser intensities, and show that these measurements match the expected extensible wormlike-chain (WLC) behavior. Finally, we also demonstrate a force-clamp, in which the tension in a tether is held fixed while the extension varies as a result of molecular events.

  13. Practical axial optical trapping

    PubMed Central

    Mack, A. H.; Schlingman, D. J.; Regan, L.; Mochrie, S. G. J.

    2012-01-01

    We describe a new method for calibrating optical trapping measurements in which tension is applied in the direction of the laser beam to a molecule tethered between a surface and an optically trapped bead. Specifically, we present a generally-applicable procedure for converting from the measured scattering intensity and the measured stage displacement to applied tension and bead-coverslip separation, using measurements of the light intensity scattered from an untethered, trapped bead. Our calibration accounts for a number of effects, including aberrations and the interference of forward-reflected bead-scattered light with the trapping beam. To demonstrate the accuracy of our method, we show measurements of the DNA force-versus-extension relation using a range of laser intensities, and show that these measurements match the expected extensible wormlike-chain (WLC) behavior. Finally, we also demonstrate a force-clamp, in which the tension in a tether is held fixed while the extension varies as a result of molecular events. PMID:23126750

  14. The Universal Trap.

    ERIC Educational Resources Information Center

    Goodman, Paul

    The compulsory system of education is criticized on the grounds that it has become a regimented "universal trap" antithetical to democracy. In contrast to the Jeffersonian concept of education in the service of citizen initiative for the preservation of freedom, current compulsory education is a tool of industrialism and of a rigidly stratified…

  15. Grid Task Execution

    NASA Technical Reports Server (NTRS)

    Hu, Chaumin

    2007-01-01

    IPG Execution Service is a framework that reliably executes complex jobs on a computational grid, and is part of the IPG service architecture designed to support location-independent computing. The new grid service enables users to describe the platform on which they need a job to run, which allows the service to locate the desired platform, configure it for the required application, and execute the job. After a job is submitted, users can monitor it through periodic notifications, or through queries. Each job consists of a set of tasks that performs actions such as executing applications and managing data. Each task is executed based on a starting condition that is an expression of the states of other tasks. This formulation allows tasks to be executed in parallel, and also allows a user to specify tasks to execute when other tasks succeed, fail, or are canceled. The two core components of the Execution Service are the Task Database, which stores tasks that have been submitted for execution, and the Task Manager, which executes tasks in the proper order, based on the user-specified starting conditions, and avoids overloading local and remote resources while executing tasks.

  16. Equivalent linearization of nonlinear forces

    NASA Astrophysics Data System (ADS)

    Meng, Guang; Xue, Zhongqing

    1987-07-01

    A method used for equivalent linearization of the two orthogonal squeeze-film forces is extended here to the general case of n degrees of freedom and n components of nonlinear forces, and the expressions for equivalent linear coefficients are derived. Nonlinear forces can be linearized by the methods of Fourier expansion, active and reactive powers, or mean-square error. The n components of nonlinear forces can all be expressed formally as the sum of an average force, a linear spring force, and a linear damping force. This paper also gives a flow chart for calculating the steady-state responses of a nonlinear system with many degrees of freedom, using the method of equivalent linearization. The resulting saving in computation time is demonstrated by a numerical example of a flexible rotor-bearing system with a noncentralized squeeze-film damper.

  17. Equivalent series and parallel equivalent circuits for metallized film capacitors

    Microsoft Academic Search

    R. W. Brown

    2007-01-01

    The most popular general purpose power and signal capacitor, the multilayer polypropylene (MPP) capacitor, exhibits virtually zero conductance losses and negligible distributed inductance. Self resonance is principally determined by lead and package inductance which can be modeled by a lumped equivalent inductor external to the capacitor. Inside the capacitor, the distributed resistance and capacitance represented by the metallization and the

  18. SWD Trapping in New Hampshire

    E-print Network

    New Hampshire, University of

    counted in traps. Traps did poorly in 2012 to predict the need to spray. Catches began long after the crop, possibly from raccoon This year, the traps did much better at predicting the need to treat. In another well. Raccoons might be a problem (yeast/flour bait). #12;

  19. MODIFICATION OF CC WHITEFLY TRAPS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modifications of CC whitefly traps are in progress to improve their potential for adult whitefly control in greenhouses. Adult catches in the modified CC traps have been increased by 50% by coating trap tops with Tanglefoot and removing the deflector plates. In laboratory studies, installation of ...

  20. [Treatment of meconium ileus equivalent].

    PubMed

    Lambrecht, W; Weinland, G; Koch, G; Gaedicke, G

    1978-07-01

    A 12-year old boy with mucoviscidosis developed a mechanical obstruction of the small intestine. The diagnosis of a meconium ileus equivalent was made and a conservative treatment was started. After this treatment failed, a laparotomy was performed which verified the diagnosis of a meconium ileus equivalent. It was possible to move the inspissated feces inside the terminal ileum into the ascending colon. The postoperative course was uneventful. The etiology, differential diagnosis, and both conservative and operative treatment of this complication of the mucoviscidosis are discussed. PMID:679786

  1. Doing without the Equivalence Principle

    E-print Network

    R. Aldrovandi; J. G. Pereira; K. H. Vu

    2004-10-08

    In Einstein's general relativity, geometry replaces the concept of force in the description of the gravitation interaction. Such an approach rests on the universality of free-fall--the weak equivalence principle--and would break down without it. On the other hand, the teleparallel version of general relativity, a gauge theory for the translation group, describes the gravitational interaction by a force similar to the Lorentz force of electromagnetism, a non-universal interaction. It is shown that, similarly to the Maxwell's description of electromagnetism, the teleparallel gauge approach provides a consistent theory for gravitation even in the absence of the weak equivalence principle.

  2. The JPL trapped mercury ion frequency standard

    NASA Astrophysics Data System (ADS)

    Prestage, J. D.; Dick, G. J.; Maleki, L.

    1988-02-01

    In order to provide frequency standards for the Deep Space Network (DSN) which are more stable than present-day hydrogen masers, a research task was established under the Advanced Systems Program of the TDA to develop a Hg-199(+) trapped ion frequency standard. The first closed-loop operation of this kind is described. Mercury-199 ions are confined in an RF trap and are state-selected through the use of optical pumping with 194 nm UV light from a Hg-202 discharge lamp. Absorption of microwave radiation at the hyperfine frequency (40.5 GHz) is signaled by atomic fluorescence of the UV light. The frequency of a 40.5 GHz oscillator is locked to a 1.6 Hz wide atomic absorption line of the trapped ions. The measured Allan variance of this locked oscillator is currently gamma sub y (pi) = 4.4 x 10 to the minus 12th/square root of pi for 20 is less than pi is less than 320 seconds, which is better stability than the best commercial cesium standards by almost a factor of 2. This initial result was achieved without magnetic shielding and without regulation of ion number.

  3. Transport quantum logic gates for trapped ions

    E-print Network

    D. Leibfried; E. Knill; C. Ospelkaus; D. J. Wineland

    2007-08-28

    Many efforts are currently underway to build a device capable of large scale quantum information processing (QIP). Whereas QIP has been demonstrated for a few qubits in several systems, many technical difficulties must be overcome in order to construct a large-scale device. In one proposal for large-scale QIP, trapped ions are manipulated by precisely controlled light pulses and moved through and stored in multizone trap arrays. The technical overhead necessary to precisely control both the ion geometrical configurations and the laser interactions is demanding. Here we propose methods that significantly reduce the overhead on laser beam control for performing single and multiple qubit operations on trapped ions. We show how a universal set of operations can be implemented by controlled transport of ions through stationary laser beams. At the same time, each laser beam can be used to perform many operations in parallel, potentially reducing the total laser power necessary to carry out QIP tasks. The overall setup necessary for implementing transport gates is simpler than for gates executed on stationary ions. We also suggest a transport-based two-qubit gate scheme utilizing microfabricated permanent magnets that can be executed without laser light.

  4. Plasma traps for beam dynamics studies

    NASA Astrophysics Data System (ADS)

    Okamoto, Hiromi

    2004-05-01

    The collective motion of a space-charge-dominated beam in an accelerator has been investigated by many researchers for many years mainly through numerical simulations and analytic calculations. The recent interest in applying high-power ion beams to diverse purposes has made the understandings of various "space-charge effects" more and more important than ever. It is, however, extremely difficult to carry out the self-consistent theoretical study of such a multi-particle system exposed to complex external driving fields. In fact, we have always been forced to introduce some assumptions or simplifying models to draw approximate conclusions. Efforts have also been devoted to the experimental study of intense beams, but we encounter many practical difficulties again. As we can easily imagine, it is a tough job to observe and measure a particle beam traveling at great speed. Further, in a real accelerator, key experimental parameters, such as beam density, betatron tunes, magnet arrangements, etc., are not well controllable over a wide range. In order to overcome all these difficulties in conventional approaches, we proposed a novel experimental method utilizing a compact plasma trap system (instead of a huge, very expensive accelerator system) [1]. The basic idea is quite simple; namely, a charged-particle beam in an accelerator, if seen from the rest frame, is physically almost equivalent to a single-species plasma in a trap system. It is thus possible to employ a plasma trap for the systematic experimental study of space-charge-dominated beams. In this talk, a typical trap design is given and its applications to some beam-dynamics problems are discussed. [1] H. Okamoto and H. Tanaka, Nucl. Instr. Meth. A 437 (1999) 178; H. Okamoto, Y. Wada and R. Takai, Nucl. Instr. Meth. A 485 (2002) 244.

  5. In-Trap Spectroscopy of Charge-Bred Radioactive Ions

    NASA Astrophysics Data System (ADS)

    Lennarz, A.; Grossheim, A.; Leach, K. G.; Alanssari, M.; Brunner, T.; Chaudhuri, A.; Chowdhury, U.; Crespo López-Urrutia, J. R.; Gallant, A. T.; Holl, M.; Kwiatkowski, A. A.; Lassen, J.; Macdonald, T. D.; Schultz, B. E.; Seeraji, S.; Simon, M. C.; Andreoiu, C.; Dilling, J.; Frekers, D.

    2014-08-01

    In this Letter, we introduce the concept of in-trap nuclear decay spectroscopy of highly charged radioactive ions and describe its successful application as a novel spectroscopic tool. This is demonstrated by a measurement of the decay properties of radioactive mass A=124 ions (here, In124 and Cs124) in the electron-beam ion trap of the TITAN facility at TRIUMF. By subjecting the trapped ions to an intense electron beam, the ions are charge bred to high charge states (i.e., equivalent to the removal of N-shell electrons), and an increase of storage times to the level of minutes without significant ion losses is achieved. The present technique opens the venue for precision spectroscopy of low branching ratios and is being developed in the context of measuring electron-capture branching ratios needed for determining the nuclear ground-state properties of the intermediate odd-odd nuclei in double-beta (??) decay.

  6. Equivalence classes for gauge theories

    E-print Network

    M. A. M. Gomes; R. R. Landim

    2006-10-04

    In this paper we go deep into the connection between duality and fields redefinition for general bilinear models involving the 1-form gauge field $A$. A duality operator is fixed based on "gauge embedding" procedure. Dual models are shown to fit in equivalence classes of models with same fields redefinitions.

  7. TUFTS IN LONDON PSYCHOLOGY EQUIVALENCIES

    E-print Network

    Patel, Aniruddh D.

    and Quantitative ... not recommended for Psychology majors PSYC2204: Design and Analysis ... not recommendedTUFTS IN LONDON PSYCHOLOGY EQUIVALENCIES Tufts in London Tufts Medford PSYC6001: Intro to Social to the ... PSY 001 PSYC1102: Methods and Approaches ... not recommended for Psychology majors PSYC1103

  8. A theory of stimulus equivalence

    Microsoft Academic Search

    Jack Capehart; Vincent J. Tempone; John Herbert

    1969-01-01

    Reconsiders the problem of stimulus equivalence (SE). Primary emphasis is placed on the related areas of stimulus generalization, transposition, and discrimination learning as examples of SE. Recent evidence has indicated that the only comprehensive approach to SE, the Hull-Spence system, is inadequate to account for many phenomena in these areas. A theory of SE based on a combination of information

  9. Teaching Spelling via Stimulus Equivalences.

    ERIC Educational Resources Information Center

    Lazar, Ronald M.; Mackay, Harry A.

    The study, involving two severely retarded adolescents, investigated whether matching to sample is capable of extending equivalence classes with spelling responses. In preliminary training, Ss were taught the matching to sample procedure by having them match color patch samples to identical color patch comparisons. The experimenters then trained…

  10. Acquired Equivalence Changes Stimulus Representations

    ERIC Educational Resources Information Center

    Meeter, M.; Shohamy, D.; Myers, C. E.

    2009-01-01

    Acquired equivalence is a paradigm in which generalization is increased between two superficially dissimilar stimuli (or antecedents) that have previously been associated with similar outcomes (or consequents). Several possible mechanisms have been proposed, including changes in stimulus representations, either in the form of added associations or…

  11. USEPA PATHOGEN EQUIVALENCY COMMITTEE RETREAT

    EPA Science Inventory

    The Pathogen Equivalency Committee held its retreat from September 20-21, 2005 at Hueston Woods State Park in College Corner, Ohio. This presentation will update the PEC’s membership on emerging pathogens, analytical methods, disinfection techniques, risk analysis, preparat...

  12. Equivalent Linear Logistic Test Models.

    ERIC Educational Resources Information Center

    Bechger, Timo M.; Verstralen, Huub H. F. M.; Verhelst, Norma D.

    2002-01-01

    Discusses the Linear Logistic Test Model (LLTM) and demonstrates that there are many equivalent ways to specify a model. Analyzed a real data set (300 responses to 5 analogies) using a Lagrange multiplier test for the specification of the model, and demonstrated that there may be many ways to change the specification of an LLTM and achieve the…

  13. Cognitive task analysis: harmonizing tasks to human capacities

    Microsoft Academic Search

    MARK A. NEERINCX; EDWIN GRIFFIOEN

    1996-01-01

    This paper presents the development of a cognitive task analysis that assesses the task load of jobs and provides indicators for the redesign of jobs. General principles of human task performance were selected and, subsequently, integrated into current task modelling techniques. The resulting cognitive task analysis centres around four aspects of task load: the number of actions in a period,

  14. Magnetic trap for thulium atoms

    SciTech Connect

    Sukachev, D D; Sokolov, A V; Chebakov, K A; Akimov, A V; Kolachevskii, N N; Sorokin, Vadim N [P N Lebedev Physical Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2011-08-31

    For the first time ultra-cold thulium atoms were trapped in a magnetic quadrupole trap with a small field gradient (20 Gs cm{sup -1}). The atoms were loaded from a cloud containing 4x10{sup 5} atoms that were preliminarily cooled in a magneto-optical trap to the sub-Doppler temperature of 80 {mu}K. As many as 4x10{sup 4} atoms were trapped in the magnetic trap at the temperature of 40 {mu}K. By the character of trap population decay the lifetime of atoms was determined (0.5 s) and an upper estimate was obtained for the rate constant of inelastic binary collisions for spin-polarised thulium atoms in the ground state (g{sub in} < 10{sup -11}cm{sup 3} s{sup -1}). (magnetic traps)

  15. Radial cold trap

    DOEpatents

    Grundy, B.R.

    1981-09-29

    The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume. 2 figs.

  16. Coherence in Microchip Traps

    E-print Network

    Treutlein, P; Steinmetz, T; Hänsch, T W; Reichel, J; Treutlein, Philipp; Hommelhoff, Peter; Steinmetz, Tilo; H\\"ansch, Theodor W.; Reichel, Jakob

    2003-01-01

    We report the coherent manipulation of internal states of neutral atoms in a magnetic microchip trap. Coherence lifetimes exceeding 1 s are observed with atoms at distances of $4-130 \\mu$m from the microchip surface. The coherence lifetime in the microtrap is independent of atom-surface distance and agrees well with the results of similar measurements in macroscopic magnetic traps. Due to the absence of surface-induced decoherence, a miniaturized atomic clock with a relative stability in the $10^{-13}$ range can be realized. For applications in quantum information processing, we propose to use microwave near-fields in the proximity of chip wires to create potentials that depend on the internal state of the atoms.

  17. TaskBadges

    NSDL National Science Digital Library

    2012-09-07

    This application is quite simple and is designed to keep life's tasks in order. Billed as "plain-text todo list kung fu," Task Badges adds the number of open tasks in your plain-text todo list to the file's icon so that it shows up in Finder and on the desktop. It's easy to use and it is compatible with Macs running Snow Leopard or Lion.

  18. The expectations trap hypothesis

    Microsoft Academic Search

    Lawrence J. Christiano; Christopher J. Gust

    2000-01-01

    The authors examine the inflation take-off of the early 1970s in terms of the expectations trap hypothesis, according to which fear of violating the public’s inflation expectations pushed the Fed into producing high inflation. This interpretation is compared with the Phillips curve hypothesis, according to which the Fed produced high inflation as the unfortunate byproduct of a conscious decision to

  19. Population inversion of nuclear states by a Penning trap mass spectrometer

    Microsoft Academic Search

    K. Blaum; D. Beck; G. Bollen; P. Delahaye; C. Guénaut; F. Herfurth; A. Kellerbauer; H.-J. Kluge; D. Lunney; S. Schwarz; L. Schweikhard; C. Yazidjian

    2004-01-01

    According to the energy-mass equivalence, E = mc2, excited long-lived nuclear states, so-called isomers, are distinguished from the ground state by their additional mass. The ultra-high accuracy provided by Penning traps now allows to weigh nuclear excitation energies. With the on-line Penning trap mass spectrometer ISOLTRAP, we have developed a mass-separation procedure of sufficient resolving power to isolate particles of

  20. Integrated Microsystems Approach to Trapped Ion Quantum Information Processing

    NASA Astrophysics Data System (ADS)

    Kim, Jungsang

    2013-05-01

    Trapped atomic ions are the leading candidate physical system for quantum information processing, featuring high quality qubits capable of high fidelity operations including state preparation, detection and quantum logic gates. A major remaining challenge is the task of constructing experimental systems where all operations necessary for quantum information processing can be performed in a scalable way. I will discuss a three-tier approach to construct such scalable hardware utilizing technologies that are available today. Arbitrary qubit gate operations in a linear ion chain (<102 ions) can be realized with control beams that can address individual ions in the chain. Shuttling of ions between such chains enable qubit gates between several chains (~ 10 chains) implemented in a single chip trap. One can then connect a large number (~103) of such trap chips using reconfigurable photonic network. Complex microfabricated ion trap chips integrated with various optical components such as reflectors, lenses and optical cavities are crucial in realizing efficient interfaces for these experiments, and micromirrors can provide fast and flexible beam delivery system with individual addressing capability. I will present the progress in ion qubit manipulation on microfabricated chip traps, the integration effort with optical components, and potential application in scalable quantum computer and quantum repeater realization. Trapped atomic ions are the leading candidate physical system for quantum information processing, featuring high quality qubits capable of high fidelity operations including state preparation, detection and quantum logic gates. A major remaining challenge is the task of constructing experimental systems where all operations necessary for quantum information processing can be performed in a scalable way. I will discuss a three-tier approach to construct such scalable hardware utilizing technologies that are available today. Arbitrary qubit gate operations in a linear ion chain (<102 ions) can be realized with control beams that can address individual ions in the chain. Shuttling of ions between such chains enable qubit gates between several chains (~ 10 chains) implemented in a single chip trap. One can then connect a large number (~103) of such trap chips using reconfigurable photonic network. Complex microfabricated ion trap chips integrated with various optical components such as reflectors, lenses and optical cavities are crucial in realizing efficient interfaces for these experiments, and micromirrors can provide fast and flexible beam delivery system with individual addressing capability. I will present the progress in ion qubit manipulation on microfabricated chip traps, the integration effort with optical components, and potential application in scalable quantum computer and quantum repeater realization. This work is supported by IARPA/ARO and DARPA.

  1. Sequential equivalence checking based on structural similarities

    Microsoft Academic Search

    C. A. J. Van Eijk

    2000-01-01

    Checking the functional equivalence of sequential circuits is an important practical problem. Because general algorithms for solving this problem require a state-space traversal of the product machine, they are computationally expensive. In this paper, we present a new method for sequential equivalence checking which utilizes functionally equivalent sig- nals to prove the equivalence of both circuits, thereby avoiding the state-

  2. Sequential equivalence checking without state space traversal

    Microsoft Academic Search

    C. A. J. van Eijk

    1998-01-01

    Because general algorithms for sequential equivalence checking require a state space traversal of the product machine, they are computationally expensive. In this paper, we present a new method for sequential equivalence checking which utilizes functionally equivalent signals to prove the equivalence of both circuits, thereby avoiding the state space traversal. The effectiveness of the proposed method is confirmed by experimental

  3. Computer Algebra Systems (CAS) as a Tool for Coaxing the Emergence of Reasoning about Equivalence of Algebraic Expressions

    ERIC Educational Resources Information Center

    Kieran, Carolyn; Saldanha, Luis

    2005-01-01

    Equivalence of algebraic expressions is at the heart of transformational work in algebra. However, we know very little about students' understanding of equivalence. This study is part of a larger project that explores the use of CAS as a didactical tool for promoting both technical and conceptual growth in high school algebra with tasks specially…

  4. CCZ-equivalence and Boolean functions

    Microsoft Academic Search

    Lilya Budaghyan; Claude Carlet

    We study further CCZ-equivalence of (n, m)-functions. We prove that for Boolean functions (that is, for m = 1), CCZ-equivalence coincides with EA-equivalence. On the contrary, we show that for (n, m)- functions, CCZ-equivalence is strictly more general than EA- equivalence when n ? 5 and m is greater or equal to the smallest positive divisor of n different from

  5. Diesel particulate trap mounting system

    SciTech Connect

    Miller, P.R.

    1992-01-21

    This patent describes a particulate trap assembly. It comprises an outer housing having a gas inlet and a gas outlet and a passageway interconnecting the gas inlet and the gas outlet; a particulate trapping means located within the passageway of the housing for trapping particles entrained in gas passing through the passageway, the passageway and the particulate trapping means having circumferential extents which fall within relatively large predetermined manufacturing tolerances respectively; tourniquet means surrounding the particulate trapping means for applying a predetermined radial pressure to the trapping means which is substantially independent of the circumferential extents of the passageway and the including an encircling element having a selectably adjustable circumferential extent for permitting the tourniquet means to conform to the circumferential extent of the particulate trapping means when mounted in compressive relationship about the particulate trapping means, and mounting means for retaining the particulate trapping means radially and axially within the passageway in a manner which imposes no further substantial radial compressive force to the particulate trapping means.

  6. Timeline Resource Analysis Program (TRAP): User's manual and program document

    NASA Technical Reports Server (NTRS)

    Sessler, J. G.

    1981-01-01

    The Timeline Resource Analysis Program (TRAP), developed for scheduling and timelining problems, is described. Given an activity network, TRAP generates timeline plots, resource histograms, and tabular summaries of the network, schedules, and resource levels. It is written in ANSI FORTRAN for the Honeywell SIGMA 5 computer and operates in the interactive mode using the TEKTRONIX 4014-1 graphics terminal. The input network file may be a standard SIGMA 5 file or one generated using the Interactive Graphics Design System. The timeline plots can be displayed in two orderings: according to the sequence in which the tasks were read on input, and a waterfall sequence in which the tasks are ordered by start time. The input order is especially meaningful when the network consists of several interacting subnetworks. The waterfall sequence is helpful in assessing the project status at any point in time.

  7. NSI security task: Overview

    NASA Technical Reports Server (NTRS)

    Tencati, Ron

    1991-01-01

    An overview is presented of the NASA Science Internet (NSI) security task. The task includes the following: policies and security documentation; risk analysis and management; computer emergency response team; incident handling; toolkit development; user consulting; and working groups, conferences, and committees.

  8. Identifying Critical Job Tasks.

    ERIC Educational Resources Information Center

    Burkhart, Jennifer

    This guide, which is intended for project directors, coordinators, and other professional staff involved in developing and delivering workplace education programs, explains the implications of identifying critical job tasks and details a process by which educational partners can facilitate identification of critical job tasks. First, critical job…

  9. The Multiple Tasks Test

    Microsoft Academic Search

    Bastiaan R Bloem; Vibeke V Valkenburg; Mathilde Slabbekoorn; Mirjam D Willemsen

    2001-01-01

    Simultaneous challenge of posture and cognition (‘dual tasks’) may predict falls better than tests of isolated components of postural control. We describe a new balance test (the Multiple Tasks Test, MTT) which (1) is based upon simultaneous assessment of multiple (>2) postural components; (2) represents everyday situations; and (3) can be applied by clinicians. Relevant risk factors for falls and

  10. Task Description Language

    NASA Technical Reports Server (NTRS)

    Simmons, Reid; Apfelbaum, David

    2005-01-01

    Task Description Language (TDL) is an extension of the C++ programming language that enables programmers to quickly and easily write complex, concurrent computer programs for controlling real-time autonomous systems, including robots and spacecraft. TDL is based on earlier work (circa 1984 through 1989) on the Task Control Architecture (TCA). TDL provides syntactic support for hierarchical task-level control functions, including task decomposition, synchronization, execution monitoring, and exception handling. A Java-language-based compiler transforms TDL programs into pure C++ code that includes calls to a platform-independent task-control-management (TCM) library. TDL has been used to control and coordinate multiple heterogeneous robots in projects sponsored by NASA and the Defense Advanced Research Projects Agency (DARPA). It has also been used in Brazil to control an autonomous airship and in Canada to control a robotic manipulator.

  11. Trapping of dust particles in a Kingdom trap

    NASA Astrophysics Data System (ADS)

    Robertson, Scott

    1995-04-01

    Experimental techniques for charging, trapping, and observing macroscopic particles (dust) are described. Particles with a sufficiently large charge-to-mass ratio (4×10-3 C/kg) are created by using hollow glass microspheres about 50 ?m in diameter charged to a potential of -30 volts by electrons from a filament. The charge spheres drop by gravity into a Kingdom trap and are trapped in near-circular orbits by a rising potential. A spherical version of the trap with a Keplerian potential is also used. Illumination from a halogen lamp is sufficient for videotapes to be made of particle dynamics. Phenomena observed in the Kingdom trap include libration due to a resonant perturbation and the resonant coupling of two adjacent orbiters. Precession due to gravity is observed in the spherical trap. Confinement times in the Kingdom trap approach an hour. Briefly discussed are the use of charged liquid droplets, a planar trap based upon the ponderomotive force and the collective phenomena of a non-neutral plasma in a Kingdom trap.

  12. Trapped Ion Frequency Standards

    NASA Astrophysics Data System (ADS)

    Tjoelker, R. L.

    1996-03-01

    Trapped ions form the basis for a high performance frequency standard since long interrogation times are possible in a nearly perturbation free environment. At JPL, approximately 2x10^6 ^199Hg+ ions are confined in a Linear Ion Trap (LIT)(J.D. Prestage, G.J. Dick, L. Maleki, J.Appl. Phys. 66, 1013 (1989).) and cooled to near room temperature by collisions with a helium buffer gas. Atomic state selection is accomplished by optical pumping using 194 nm light from a ^202Hg lamp and the 40.5 GHz ground state hyperfine transition is interrogated using Ramsey successive oscillatory fields. With an interrogation time of 8 seconds, the measured fractional frequency stability is ?_y(?)=6.5x10-14/ ?^1/2, where ? is the averaging interval in seconds. The frequency stability measured between two Hg^+ ion standards currently exceeds other standards between 10,000 seconds and 1 month. (R.L. Tjoelker, J.D. Prestage, L. Maleki, in Symp. on Freq. Standards & Metrology, Woods Hole MA,(1995).) The long term differential drift between an ion standard and a cavity tuned hydrogen maser over a 5 month interval was measured to be (2.1± 0.8)x10-16/day. A new two segment linear ion trap currently under development separates the ion loading and atomic state selection region from the microwave interrogation region. Initial measurements indicate a stability of ?_y(?)=5.6x10-14/ ?^1/2. Operating at reduced linear ion densities, this configuration should allow for improved accuracy and long term stability.

  13. Concept acquisition as a function of stimulus-equivalence pretraining with identical and dissimilar stimuli

    Microsoft Academic Search

    Richard D. Petre

    1964-01-01

    A matching-to-sample concept-learning task was given to 4 experimental groups and 1 control group of 25 under-graduates each. The matching was on the basis of size (large or small) and linearity (circles and crescents or squares and triangles). The experimental groups were given a stimulus-equivalence pretraining task. 2 of the groups were trained with stimuli identical to those used in

  14. Assessing stimulus equivalence with a precursor to the relational evaluation procedure

    Microsoft Academic Search

    Paul M Smeets; Marije van Wijngaarden; Dermot Barnes-Holmes; Veronica Cullinan

    2004-01-01

    Previous research has demonstrated that, after being trained on multiple match-to-sample (MTS) tasks (A–B, B–C), most human adults respond in accordance with symmetry (B–A, C–B) and equivalence (C–A) when measured with MTS tests and with a precursor to the Relational Evaluation Procedure (pREP). The latter procedure involves conditional go\\/no-go discrimination tasks, requiring subjects to press a bar during a 5s

  15. Atom trap trace analysis

    SciTech Connect

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O'Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  16. Build a Fruit Fly Trap

    NSDL National Science Digital Library

    2011-08-20

    In this construction activity, students use a 2-liter bottle to build a fly trap. There is not much supporting information besides the directions, but the trap can be used to examine fly behavior, and it might also be redesigned by students. In the construction part of the activity, younger learners will need help and supervision from an older learner or adult, but any age learner can do independent observation of fly behavior once insects are inside the trap.

  17. Optical traps with geometric aberrations

    SciTech Connect

    Roichman, Yael; Waldron, Alex; Gardel, Emily; Grier, David G

    2006-05-20

    We assess the influence of geometric aberrations on the in-plane performance of optical traps by studying the dynamics of trapped colloidal spheres in deliberately distorted holographic optical tweezers. The lateral stiffness of the traps turns out to be insensitive to moderate amounts of coma, astigmatism, and spherical aberration. Moreover holographic aberration correction enables us to compensate inherent shortcomings in the optical train, thereby adaptively improving its performance. We also demonstrate the effects of geometric aberrations on the intensity profiles of optical vortices, whose readily measured deformations suggest a method for rapidly estimating and correcting geometric aberrations in holographic trapping systems.

  18. Organic magnetoresistance from deep traps

    NASA Astrophysics Data System (ADS)

    Harmon, N. J.; Flatté, M. E.

    2014-07-01

    We predict that singly occupied carrier traps, produced by electrical stress or irradiation within organic semiconductors, can cause spin blockades and the large room-temperature magnetoresistance known as organic magnetoresistance. The blockade occurs because many singly occupied traps can only become as doubly occupied in a spin-singlet configuration. Magnetic-field effects on spin mixing during transport dramatically modify the effects of this blockade and produce magnetoresistance. We calculate the quantitative effects of these traps on organic magnetoresistance from percolation theory and find a dramatic nonlinear dependence of the saturated magnetoresistance on trap density, leading to values ˜ 20%, within the theory's range of validity.

  19. On opulence driven poverty traps.

    PubMed

    Van Marrewijk, C; Verbeek, J

    1993-01-01

    "We opt in this study to endogenize the growth rate of the population in such a way that it stresses the empirically supported negative relation between fertility and per capita income. Fertility declines as per capita income rises." The authors conclude that "the less developed economy can get stuck in a variant of the 'Malthusian trap', also called the poverty trap. The only way out of the poverty trap is through an injection of capital (a large transfer) from abroad. Our model therefore, supports...[the] view that aid from the developed countries to the less developed countries has to be increased dramatically...to overcome the poverty trap...." PMID:12285976

  20. Gated charged-particle trap

    DOEpatents

    Benner, W. Henry (Danville, CA)

    1999-01-01

    The design and operation of a new type of charged-particle trap provides simultaneous measurements of mass, charge, and velocity of large electrospray ions. The trap consists of a detector tube mounted between two sets of center-bored trapping plates. Voltages applied to the trapping plates define symmetrically-opposing potential valleys which guide axially-injected ions to cycle back and forth through the charge-detection tube. A low noise charge-sensitive amplifier, connected to the tube, reproduces the image charge of individual ions as they pass through the detector tube. Ion mass is calculated from measurement of ion charge and velocity following each passage through the detector.

  1. Stimulus equivalence, generalization, and contextual stimulus control in verbal classes.

    PubMed

    Sigurðardóttir, Zuilma Gabriela; Mackay, Harry A; Green, Gina

    2012-01-01

    Stimulus generalization and contextual control affect the development of equivalence classes. Experiment 1 demonstrated primary stimulus generalization from the members of trained equivalence classes. Adults were taught to match six spoken Icelandic nouns and corresponding printed words and pictures to one another in computerized three-choice matching-to-sample tasks. Tests confirmed that six equivalence classes had formed. Without further training, plural forms of the stimuli were presented in tests for all matching performances. All participants demonstrated virtually errorless performances. In Experiment 2, classifications of the nouns used in Experiment 1 were brought under contextual control. Three nouns were feminine and three were masculine. The match-to-sample training taught participants to select a comparison of the same number as the sample (i.e., singular or plural) in the presence of contextual stimulus A regardless of noun gender. Concurrently, in the presence of contextual stimulus B, participants were taught to select a comparison of the same gender as the sample (i.e., feminine or masculine), regardless of number. Generalization was assessed using a card-sorting test. All participants eventually sorted the cards correctly into gender and number stimulus classes. When printed words used in training were replaced by their picture equivalents, participants demonstrated almost errorless performances. PMID:22754102

  2. The effects of three statistical control charts on task performance

    Microsoft Academic Search

    Kuoh How Ong; Craig M. Harvey; Randa L. Shehab; Jerry D. Dechert; Ashok Darisipudi

    2004-01-01

    This study investigated the effects of graphical characteristics on three common statistical process control (SPC) charts, Shewhart , exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) charts, with a near-equivalent statistical performance. Three main tasks, identification of out-of-control (OOC) points, estimation of process mean and identification of process pattern, were designed to evaluate the effectiveness of these charts. Participant

  3. Thermal Replication Trap

    NASA Astrophysics Data System (ADS)

    Braun, Dieter

    2011-03-01

    The hallmark of living matter is the replication of genetic molecules and their active storage against diffusion. We have argued in the past that thermal convection can host the million-fold accumulation even of single nucleotides and at the same time trigger exponential replication. Accumulation is driven by thermophoresis and convection in elongated chambers, replication by the inherent temperature cycling in convection. Optothermal pumping [2,3] allows to implement the thermal trap efficiently in a toroidal or linear geometry. Based on this method, we were in a position to combine accumulation and replication of DNA in the same chamber. As we are missing a solid chemistry of prebiotic replication, we used as a proxy reaction for to replication the polymerase chain reaction. Convective flow both drives the DNA replicating polymerase chain reaction (PCR) while concurrent thermophoresis accumulates the replicated 143 base pair DNA in bulk solution. The time constant for accumulation is 92 s while DNA is doubled every 50 s. The length of the amplified DNA is checked with thermophoresis. Finite element simulations confirm the findings. The experiments explore conditions in pores of hydrothermal rock which can serve as a model environment for the origin of life and has prospects towards the first autonomous evolution, hosting the Darwin process by molecular selection using the thermophoretic trap. On the other side, the implemented continuous evolution will be able to breed well specified DNA or RNA molecules in the future.

  4. Solar light trapping in slanted conical-pore photonic crystals: Beyond statistical ray trapping

    NASA Astrophysics Data System (ADS)

    Eyderman, Sergey; John, Sajeev; Deinega, Alexei

    2013-04-01

    We demonstrate that with only 1 ?m, equivalent bulk thickness, of crystalline silicon, sculpted into the form of a slanted conical-pore photonic crystal and placed on a silver back-reflector, it is possible to attain a maximum achievable photocurrent density (MAPD) of 35.5 mA/cm2 from impinging sunlight. This corresponds to absorbing roughly 85% of all available sunlight in the wavelength range of 300-1100 nm and exceeds the limits suggested by previous "statistical ray trapping" arguments. Given the AM 1.5 solar spectrum and the intrinsic absorption characteristics of silicon, the optimum carrier generation occurs for a photonic crystal square lattice constant of 850 nm and slightly overlapping inverted cones with upper (base) radius of 500 nm. This provides a graded refractive index profile with good anti-reflection behavior. Light trapping is enhanced by tilting each inverted cone such that one side of each cone is tangent to the plane defining the side of the elementary cell. When the solar cell is packaged with silica (each pore filled with SiO2), the MAPD in the wavelength range of 400-1100 nm becomes 32.6 mA/cm2 still higher than the Lambertian 4n2 benchmark of 31.2 mA/cm2. In the near infrared regime from 800 to 1100 nm, our structure traps and absorbs light within slow group velocity modes, which propagate nearly parallel to the solar cell interface and exhibit localized high intensity vortex-like flow in the Poynting vector-field. In this near infrared range, our partial MAPD is 10.9 mA/cm2 compared to a partial MAPD of 7 mA/cm2 based on "4n2 statistical ray trapping." These results suggest silicon solar cell efficiencies exceeding 20% with just 1 ?m of silicon.

  5. A single trapped ion in a finite range trap

    SciTech Connect

    Bagheri Harouni, M., E-mail: m-bagheri@phys.ui.ac.ir [Department of Physics, Faculty of Science, University of Isfahan, Hezar Jerib St., Isfahan 81764-73441 (Iran, Islamic Republic of); Davoudi Darareh, M., E-mail: m.davoudi@sci.ui.ac.ir [Department of Physics, Faculty of Science, University of Isfahan, Hezar Jerib St., Isfahan 81764-73441 (Iran, Islamic Republic of); Department of Physics, Malek-ashtar University of Technology, Shahin-shahr, P.O. Box 83145/115 (Iran, Islamic Republic of)

    2011-04-15

    Research Highlights: > We present a method to describe dynamics of an ion confined in a finite size trap. > The trap is modeled with a potential in the context of an f-deformed oscillator. > The ion exhibits nonclassical properties such as squeezing and quantum interference. > . > Also this system can be used to generate highly excited motional Fock state. > The Hilbert space size effects and nano traps can be investigated by this model. - Abstract: This paper presents a method to describe dynamics of an ion confined in a realistic finite range trap. We model this realistic potential with a solvable one and we obtain dynamical variables (raising and lowering operators) of this potential. We consider coherent interaction of this confined ion in a finite range trap and we show that its center-of-mass motion steady state is a special kind of nonlinear coherent states. Physical properties of this state and their dependence on the finite range of potential are studied.

  6. Cryogenic Ion Trapping Systems with Surface-Electrode Traps

    E-print Network

    P. B. Antohi; D. Schuster; G. M. Akselrod; J. Labaziewicz; Y. Ge; Z. Lin; W. S. Bakr; I. L. Chuang

    2008-07-29

    We present two simple cryogenic RF ion trap systems in which cryogenic temperatures and ultra high vacuum pressures can be reached in as little as 12 hours. The ion traps are operated either in a liquid helium bath cryostat or in a low vibration closed cycle cryostat. The fast turn around time and availability of buffer gas cooling made the systems ideal for testing surface-electrode ion traps. The vibration amplitude of the closed cycled cryostat was found to be below 106 nm. We evaluated the systems by loading surface-electrode ion traps with $^{88}$Sr$^+$ ions using laser ablation, which is compatible with the cryogenic environment. Using Doppler cooling we observed small ion crystals in which optically resolved ions have a trapped lifetime over 2500 minutes.

  7. The Equivalency between Logic Petri Workflow Nets and Workflow Nets

    PubMed Central

    Wang, Jing; Yu, ShuXia; Du, YuYue

    2015-01-01

    Logic Petri nets (LPNs) can describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. Logic Petri workflow nets (LPWNs) are proposed based on LPNs in this paper. Process mining is regarded as an important bridge between modeling and analysis of data mining and business process. Workflow nets (WF-nets) are the extension to Petri nets (PNs), and have successfully been used to process mining. Some shortcomings cannot be avoided in process mining, such as duplicate tasks, invisible tasks, and the noise of logs. The online shop in electronic commerce in this paper is modeled to prove the equivalence between LPWNs and WF-nets, and advantages of LPWNs are presented. PMID:25821845

  8. Strategies of coding and processing in a physical same-different-task1

    Microsoft Academic Search

    Thomas Lachmann

    The theory of Memory-guided Inference explains the representation of seemingly redundant information as useful to obtain economy in a more encompassing representational scheme. Likewise, task execution can have seemingly redundant steps, which subserve economy requirements in a wider context. Visual patterns related by geometrical equivalence transformations instantiate the concept of seeming redundancy in particularly striking ways. These patterns form equivalence

  9. Delegation of Tasks Form

    Cancer.gov

    Updated: December 2010Form: DR, #1, created 08/03/04; updated 2/11/10Form: DR, #1, created 08/03/04; updated 2/11/10Delegation of Tasks Principal Investigator: __________________________________________ Site: ________________________________________________________ Sponsor:

  10. Job and Task Analysis

    ERIC Educational Resources Information Center

    And Others; Morris, Johnnye M.

    1972-01-01

    Job and task analyses for bus boy, short order cook, and child care aide; also contains a career ladder for a child care center and proposed course of study and job analysis form for child care aide. (SB)

  11. Task and Databases

    Microsoft Academic Search

    Kai-Fu Lee

    \\u000a We will be evaluating SPHINX on the resource management task [Price 88]. This task was designed for inquiry of naval resources, but can be generalized to database query. It was\\u000a created to evaluate the recognizers of the recent DARPA projects, for example, CMU’s speaker-independent ANGEL system [Adams\\u000a 86], and BBN’s speaker-dependent BYBLOS system [Chow 87].

  12. TecTask

    NSDL National Science Digital Library

    The Task Group on Tectonics and Structural Geology (TecTask)

    The Task Group on Tectonics and Structural Geology (TecTask) is a committee of the IUGS that represents an initiative of earth scientists dedicated to stimulating communication and coordination within the international science community and to providing information to the public. The site features links to conferences, data, and downloadable software, as well as journals, organizations and societies dedicated to various aspects of structural geology.

  13. Light WIMPs and Equivalent Neutrinos

    NASA Astrophysics Data System (ADS)

    Steigman, Gary; Nollett, Kenneth M.

    Very light WIMPs (?), thermal relics that annihilate late in the early Universe, change the energy and entropy densities at BBN and at recombination. BBN, in combination with the CMB, can remove some of the degeneracies among light WIMPs and equivalent neutrinos, constraining the existence and properties of each. Depending on the nature of the light WIMP (Majorana or Dirac fermion, real or complex scalar) the joint BBN + CMB analyses set lower bounds to m? in the range 0.5 - 5 MeV (m?/me ?1 - 10), and they identify best fit values for m? in the range 5 - 10 MeV. The joint BBN + CMB analysis finds a best fit value for the number of equivalent neutrinos, ?N? ? 0.65, nearly independent of the nature of the WIMP. In the absence of a light WIMP (m? ?20 MeV), Neff = 3.05(1 + ?N?/3). In this case, there is excellent agreement between BBN and the CMB, but the joint fit reveals ?N? = 0.40 ± 0.17, disfavoring standard big bang nucleosynthesis (SBBN) (?N? = 0) at ? 2.4 ?, as well as a sterile neutrino (?N? = 1) at ? 3.5 ?. The best BBN + CMB joint fit disfavors the absence of dark radiation (?N? = 0 at ? 95% confidence), while allowing for the presence of a sterile neutrino (?N? = 1 at ?1 ?). For all cases considered here, the lithium problem persists. These results, presented at the TAUP 2013 Conference, are based on Nollett & Steigman [14].

  14. Speed analyses of stimulus equivalence.

    PubMed Central

    Spencer, T J; Chase, P N

    1996-01-01

    The functional substitutability of stimuli in equivalence classes was examined through analyses of the speed of college students' accurate responding. After training subjects to respond to 18 conditional relations, subjects' accuracy and speed of accurate responding were compared across trial types (baseline, symmetry, transitivity, and combined transitivity and symmetry) and nodal distance (one- through five-node transitive and combined transitive and symmetric relations). Differences in accuracy across nodal distance and trial type were significant only on the first tests of equivalence, whereas differences in speed were significant even after extended testing. Response speed was inversely related to the number of nodes on which the tested relations were based. Significant differences in response speed were also found across trial types, except between transitivity and combined trials. To determine the generality of these comparisons, three groups of subjects were included: An instructed group was given an instruction that specified the interchangeability of stimuli related through training; a queried group was queried about the basis for test-trial responding: and a standard group was neither instructed nor queried. There were no significant differences among groups. These results suggest the use of response speed and response accuracy to measure the strength of matching relations. PMID:8636663

  15. Nontoxic Antifreeze for Insect Traps

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Propylene glycol in water is a safe and effective alternative to ethylene glycol as a capture liquid in insect traps (pitfalls, flight intercepts, pan traps). Propylene glycol formulations are readily available because it is the primary (95%) ingredient in certain automotive antifreeze formulations...

  16. Mass trapping for Anastrepha suspensa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mass trapping has been found to be highly effective for control of pest fruit flies when populations are low and a highly effective lure is available for the target species. Successful population control through mass trapping is an indicator that attract-and-kill bait stations may be equally succes...

  17. Cryogenic silicon surface ion trap

    E-print Network

    Michael Niedermayr; Kirill Lakhmanskiy; Muir Kumph; Stefan Partel; Johannes Edlinger; Michael Brownnutt; Rainer Blatt

    2015-05-01

    Trapped ions are pre-eminent candidates for building quantum information processors and quantum simulators. They have been used to demonstrate quantum gates and algorithms, quantum error correction, and basic quantum simulations. However, to realise the full potential of such systems and make scalable trapped-ion quantum computing a reality, there exist a number of practical problems which must be solved. These include tackling the observed high ion-heating rates and creating scalable trap structures which can be simply and reliably produced. Here, we report on cryogenically operated silicon ion traps which can be rapidly and easily fabricated using standard semiconductor technologies. Single $^{40}$Ca$^+$ ions have been trapped and used to characterize the trap operation. Long ion lifetimes were observed with the traps exhibiting heating rates as low as $\\dot{\\bar{n}}=$ 0.33 phonons/s at an ion-electrode distance of 230 $\\mu$m. These results open many new avenues to arrays of micro-fabricated ion traps.

  18. Equivalence of Learning Algorithms Julien Audiffren1

    E-print Network

    squares regression (M-RLSR) algorithms. 1 Introduction Equivalence is a fundamental concept that definesEquivalence of Learning Algorithms Julien Audiffren1 and Hachem Kadri2 1 CMLA, ENS Cachan is to introduce a concept of equivalence between machine learn- ing algorithms. We define two notions

  19. Stimulus Equivalence: Testing Sidman's (2000) Theory

    ERIC Educational Resources Information Center

    Minster, Sara Tepaeru; Jones, Max; Elliffe, Douglas; Muthukumaraswamy, Suresh D.

    2006-01-01

    Sidman's (2000) theory regarding the origin of equivalence relations predicts that a reinforcing stimulus common to distinct equivalence classes must drop out of the equivalence relations. This prediction was tested in the present study by arranging class-specific reinforcers, R1 and R2, following correct responding on the prerequisite conditional…

  20. Tests of the weak equivalence principle

    Microsoft Academic Search

    C C Speake; C M Will

    2012-01-01

    The Einstein equivalence principle is the foundation for general relativity and all metric theories of gravity. Of its three tenets—the equality of acceleration of test bodies, or weak equivalence principle; the validity of Lorentz invariance in local freely falling frames; and the position invariance of local physical laws—the weak equivalence principle has played the most important role historically, and continues

  1. Theory and application of planar ion traps

    E-print Network

    Pearson, Christopher Elliott

    2006-01-01

    In this thesis, we investigate a new geometry of Paul trap with electrodes in a plane. These planar ion traps are compatible with modern silicon microfabrication, and can be scaled up to large arrays with multiple trapping ...

  2. Nanocarpets for Trapping Microscopic Particles

    NASA Technical Reports Server (NTRS)

    Noca, Flavio; Chen, Fei; Hunt, Brian; Bronikowski, Michael; Hoenk, Michael; Kowalczyk, Robert; Choi, Daniel

    2004-01-01

    Nanocarpets that is, carpets of carbon nanotubes are undergoing development as means of trapping microscopic particles for scientific analysis. Examples of such particles include inorganic particles, pollen, bacteria, and spores. Nanocarpets can be characterized as scaled-down versions of ordinary macroscopic floor carpets, which trap dust and other particulate matter, albeit not purposefully. Nanocarpets can also be characterized as mimicking both the structure and the particle-trapping behavior of ciliated lung epithelia, the carbon nanotubes being analogous to cilia. Carbon nanotubes can easily be chemically functionalized for selective trapping of specific particles of interest. One could, alternatively, use such other three-dimensionally-structured materials as aerogels and activated carbon for the purposeful trapping of microscopic particles. However, nanocarpets offer important advantages over these alternative materials: (1) Nanocarpets are amenable to nonintrusive probing by optical means; and (2) Nanocarpets offer greater surface-to-volume ratios.

  3. Optimal traps in graphene

    E-print Network

    C. A. Downing; A. R. Pearce; R. J. Churchill; M. E. Portnoi

    2015-03-27

    We transform the two-dimensional Dirac-Weyl equation, which governs the charge carriers in graphene, into a non-linear first-order differential equation for scattering phase shift, using the so-called variable phase method. This allows us to utilize the Levinson Theorem to find zero-energy bound states created electrostatically in realistic structures. These confined states are formed at critical potential strengths, which leads to us posit the use of `optimal traps' to combat the chiral tunneling found in graphene, which could be explored experimentally with an artificial network of point charges held above the graphene layer. We also discuss scattering on these states and find the zero angular momentum states create a dominant peak in scattering cross-section as energy tends towards the Dirac point energy, suggesting a dominant contribution to resistivity.

  4. Segmented trapped vortex cavity

    NASA Technical Reports Server (NTRS)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  5. TGFF: task graphs for free

    Microsoft Academic Search

    Robert P. Dick; David L. Rhodes; Wayne Wolf

    1998-01-01

    We present a user-controllable, general-purpose,pseudorandom task graph generator called TaskGraphs For Free (TGFF). TGFF creates probleminstances for use in allocation and scheduling research.It has the ability to generate independenttasks as well as task sets which are composed of partiallyordered task graphs. A complete description ofa scheduling problem instance is created, includingattributes for processors, communication resources,tasks, and inter-task communication. The user...

  6. Trapping tsetse flies on water.

    PubMed

    Laveissière, C; Camara, M; Rayaisse, J B; Salou, E; Kagbadouno, M; Solano, P

    2011-05-01

    Riverine tsetse flies such as Glossina palpalis gambiensis and G. tachinoides are the vectors of human and animal trypanosomoses in West Africa. Despite intimate links between tsetse and water, to our knowledge there has never been any attempt to design trapping devices that would catch tsetse on water. In mangrove (Guinea) one challenging issue is the tide, because height above the ground for a trap is a key factor affecting tsetse catches. The trap was mounted on the remains of an old wooden dugout, and attached with rope to nearby branches, thereby allowing it to rise and fall with the tide. Catches showed a very high density of 93.9 flies/"water-trap"/day, which was significantly higher (p < 0.05) than all the catches from other habitats where the classical trap had been used. In savannah, on the Comoe river of South Burkina Faso, the biconical trap was mounted on a small wooden raft anchored to a stone, and catches were compared with the classical biconical trap put on the shores. G. p. gambiensis and G. tachinoides densities were not significantly different from those from the classical biconical one. The adaptations described here have allowed to efficiently catch tsetse on the water, which to our knowledge is reported here for the first time. This represents a great progress and opens new opportunities to undertake studies on the vectors of trypanosomoses in mangrove areas of Guinea, which are currently the areas showing the highest prevalences of sleeping sickness in West Africa. It also has huge potential for tsetse control using insecticide impregnated traps in savannah areas where traps become less efficient in rainy season. The Guinean National control programme has already expressed its willingness to use such modified traps in its control campaigns in Guinea, as has the national PATTEC programme in Burkina Faso during rainy season. PMID:21678789

  7. An Analysis of Synchrony between Concrete-operational Tasks in Terms of Structural and Performance Demands

    ERIC Educational Resources Information Center

    Toussaint, N. A.

    1974-01-01

    A set of tasks theoretically presumed to require equivalent logical competence (multiplication of classes, multiplication of relations, seriation, and transitivity) was administered to 64 first and second graders. Response measures emphasizing the operative and figurative aspects were compared within each task. (Author/SDH)

  8. Impact of Static Graphics, Animated Graphics and Mental Imagery on a Complex Learning Task

    ERIC Educational Resources Information Center

    Lai, Feng-Qi; Newby, Timothy J.

    2012-01-01

    The present study compared the impact of different categories of graphics used within a complex learning task. One hundred eighty five native English speaking undergraduates participated in a task that required learning 18 Chinese radicals and their English equivalent translations. A post-test only control group design compared performance…

  9. Cooling and trapping polar molecules in an electrostatic trap

    NASA Astrophysics Data System (ADS)

    Wang, Zhen-Xia; Zhen-Xing, Gu; Deng, Lian-Zhong; Yin, Jian-Ping

    2015-05-01

    An electrostatic trap for polar molecules is proposed. Loading and trapping of polar molecules can be realized by applying different voltages to the two electrodes of the trap. For ND3 molecular beams centered at ?10 m/s, a high loading efficiency of ?67% can be obtained, as confirmed by our Monte Carlo simulations. The volume of our trap is as large as ?3.6 cm3, suitable for study of the adiabatic cooling of trapped molecules. Our simulations indicate that trapped ND3 molecules can be cooled from ?23.3 mK to 1.47 mK by reducing the trapping voltages on the electrodes from 50.0 kV to 1.00 kV. Project supported by the National Natural Science Foundation of China (Grant Nos. 10674047, 10804031, 10904037, 10974055, 11034002, and 11274114), the National Key Basic Research and Development Program of China (Grant Nos. 2006CB921604 and 2011CB921602), the Basic Key Program of Shanghai Municipality, China (Grant No. 07JC14017), and the Shanghai Leading Academic Discipline Project, China (Grant No. B408).

  10. Auditory-Visual and Visual-Visual Equivalence Relations in Children

    ERIC Educational Resources Information Center

    Smeets, Paul M.; Barnes-Holmes, Dermot

    2005-01-01

    Previous research has suggested that persons with mental retardation evidence equivalence more readily after being trained on auditory-visual than on visual-visual match-to-sample tasks. The present study sought to determine if this discrepancy is also apparent in normally capable preschoolers and whether the derived class-consistent test…

  11. The Case of Bruce: A Teacher's Model of His Students' Algebraic Thinking about Equivalent Expressions

    ERIC Educational Resources Information Center

    Hallagan, Jean E.

    2006-01-01

    The purpose of this article is to describe a middle school mathematics teacher's model of his students' responses to algebraic tasks involving equivalent expressions and the distributive property. The teacher engaged in two model-eliciting activities designed for teachers by creating a library of his students' work and an accompanying "Ways of…

  12. Effects of a CARO on Stimulus Equivalence Formation: A Systematic Replication

    ERIC Educational Resources Information Center

    Imam, Abdulrazaq A.; Blanche, Justin V.

    2013-01-01

    In two experiments, we examined the disruptive effects of a "can't answer" response option (CARO) on equivalence formation. The first experiment was a systematic replication of Duarte, Eikeseth, Rosales-Ruiz, and Baer (1998), in which participants in a CARO group and a No-CARO group performed conditional discrimination tasks with abstract stimuli…

  13. Equivalent crystal theory of alloys

    NASA Technical Reports Server (NTRS)

    Bozzolo, Guillermo; Ferrante, John

    1991-01-01

    Equivalent Crystal Theory (ECT) is a new, semi-empirical approach to calculating the energetics of a solid with defects. The theory has successfully reproduced surface energies in metals and semiconductors. The theory of binary alloys to date, both with first-principles and semi-empirical models, has not been very successful in predicting the energetics of alloys. This procedure is used to predict the heats of formation, cohesive energy, and lattice parameter of binary alloys of Cu, Ni, Al, Ag, Au, Pd, and Pt as functions of composition. The procedure accurately reproduces the heats of formation versus composition curves for a variety of binary alloys. The results are then compared with other approaches such as the embedded atom and lattice parameters of alloys from pure metal properties more accurately than Vegard's law is presented.

  14. Inhomogeneity parameter in designing an ion trap

    E-print Network

    Weikang Fan

    2015-01-08

    In designing an ion trap, geometry and rf source should be optimized such that the trap depth is maximized while the ion remain stable. In a quadrupole linear trap, stable parameters $a$ and $q$ are utilized frequently in describing the stability. However, in a surface trap, the trap have to be mapped to the linear quadrupole trap so that $a$ and $q$ can be evaluated. This work explains how to handle them for surface trap designing and how the geometry and rf source affect it. We conclude that the $q$ parameter should be 0.2~0.22 so that the trap is stable.

  15. Task-specific Dystonias

    PubMed Central

    Torres-Russotto, Diego; Perlmutter, Joel S.

    2009-01-01

    Task-specific dystonias are primary focal dystonias characterized by excessive muscle contractions producing abnormal postures during selective motor activities that often involve highly skilled, repetitive movements. Historically these peculiar postures were considered psychogenic but have now been classified as forms of dystonia. Writer’s cramp is the most commonly identified task-specific dystonia and has features typical of this group of disorders. Symptoms may begin with lack of dexterity during performance of a specific motor task with increasingly abnormal posturing of the involved body part as motor activity continues. Initially, the dystonia may manifest only during the performance of the inciting task, but as the condition progresses it may also occur during other activities or even at rest. Neurological exam is usually unremarkable except for the dystonia-related abnormalities. Although the precise pathophysiology remains unclear, increasing evidence suggests reduced inhibition at different levels of the sensorimotor system. Symptomatic treatment options include oral medications, botulinum toxin injections, neurosurgical procedures, and adaptive strategies. Prognosis may vary depending upon body part involved and specific type of task affected. Further research may reveal new insights into the etiology, pathophysiology, natural history, and improved treatment of these conditions. PMID:18990127

  16. Task-specific tremor.

    PubMed

    Bain, Peter G

    2011-01-01

    Task-specific tremor is a form of action tremor that occurs only or mainly when a person is performing a specific skilled task. The most frequently encountered form of task-specific tremor is primary writing tremor (PWT). Currently, there is debate about whether PWT is a variant of essential tremor, writer's cramp (dystonia), a separate entity, or in some cases related to essential tremor and in others to dystonia. PWT typically occurs at a frequency of 5-7Hz and has been subdivided into to two types: Type A, task-induced tremor, and type B, positionally sensitive tremor. Temporary suppression of the tremor by alcohol is seen in about one-third of cases. There are no randomized controlled therapeutic studies involving patients with PWT, although anecdotal reports of beneficial responses to propranolol, primidone, anticholinergics, botulinum toxin treatment, and stereotactic surgery have been reported. Reciprocal inhibition of the H-reflex and intracortical excitability are normal in PWT, unlike writer's cramp. Hyperactivity in the cerebellar hemispheres has been demonstrated with positron emission tomography in PWT. Other task-specific tremors have been described but have not been studied in detail. PMID:21496617

  17. Tasks matter: modeling group task processes in experimental CSCW research

    Microsoft Academic Search

    Brian E. Mennecke; Bradley C. Wheeler

    1993-01-01

    The authors present a model of how individuals process tasks in a group setting. They review the literature on tasks and integrate this literature in the context of experimental collaborative group work. The bulk of the task literature suggests that a workable and valid classification system must be built both on characteristics that are innate to a task and on

  18. Combined acoustic and optical trapping

    PubMed Central

    Thalhammer, G.; Steiger, R.; Meinschad, M.; Hill, M.; Bernet, S.; Ritsch-Marte, M.

    2011-01-01

    Combining several methods for contact free micro-manipulation of small particles such as cells or micro-organisms provides the advantages of each method in a single setup. Optical tweezers, which employ focused laser beams, offer very precise and selective handling of single particles. On the other hand, acoustic trapping with wavelengths of about 1 mm allows the simultaneous trapping of many, comparatively large particles. With conventional approaches it is difficult to fully employ the strengths of each method due to the different experimental requirements. Here we present the combined optical and acoustic trapping of motile micro-organisms in a microfluidic environment, utilizing optical macro-tweezers, which offer a large field of view and working distance of several millimeters and therefore match the typical range of acoustic trapping. We characterize the acoustic trapping forces with the help of optically trapped particles and present several applications of the combined optical and acoustic trapping, such as manipulation of large (75 ?m) particles and active particle sorting. PMID:22025990

  19. Radiation-trapping in a plane-parallel slab

    NASA Astrophysics Data System (ADS)

    Molisch, Andreas F.; Oehry, Bernhard P.; Magerl, Gottfried

    1992-10-01

    We treat the trapping of resonance radiation in a plane-parallel slab geometry, emphasizing the importance of higher-order spatial modes of excited atoms. The whole range of opacities and all commonly encountered line shapes (single or hyperfine-split spectral lines of Lorentzian, Doppler, or Voigt profiles) are covered. For the basic line shapes (Doppler and Lorentz), we solve the Holstein-Biberman equation numerically and give simple analytic fitting formulas for the shape and the trapping factor of the ground mode and higher-order modes. The results are checked and extended to more general line shapes with a quite different approach, a Monte-Carlo simulation. For the treatment of Voigt profiles, we modify common interpolation formulas for the trapping factor to make them applicable at all opacities. We critically review the Milne-Samson theory that is often used in the low-opacity regime for arbitrarily complicated lineshapes; a new definition of the equivalent opacity considerably increases its range of applicability. Almost all practically occurring radiation-trapping problems in a plane-parallel slab geometry can be treated with the present approach.

  20. A reservoir trap for antiprotons

    E-print Network

    Smorra, Christian; Franke, Kurt; Nagahama, Hiroki; Schneider, Georg; Higuchi, Takashi; Van Gorp, Simon; Blaum, Klaus; Matsuda, Yasuyuki; Quint, Wolfgang; Walz, Jochen; Yamazaki, Yasunori; Ulmer, Stefan

    2015-01-01

    We have developed techniques to extract arbitrary fractions of antiprotons from an accumulated reservoir, and to inject them into a Penning-trap system for high-precision measurements. In our trap-system antiproton storage times > 1.08 years are estimated. The device is fail-safe against power-cuts of up to 10 hours. This makes our planned comparisons of the fundamental properties of protons and antiprotons independent from accelerator cycles, and will enable us to perform experiments during long accelerator shutdown periods when background magnetic noise is low. The demonstrated scheme has the potential to be applied in many other precision Penning trap experiments dealing with exotic particles.

  1. Nontarget Captures (luring Small Mammal Trapping with Snap Traps

    Microsoft Academic Search

    David G. Peitz; Philip A. Tappe; Ronald E. Thill; Roger W. Perry; M. Anthony Melchiors; T. Bentiy Wigley

    2001-01-01

    There is little published information available on non-target captures during small mammal trapping. We used a variety of snap traps baited with a rolled oat-peanut butter mix to capture 2,054 individuals from 9 genera of small mammals in a study of small mammal and avian community structure in riparian areas and adjacent loblolly pine (Pinus taeda) plantations. We also captured

  2. [Solution of trap tube test by hooded crows (Corvus cornix L.)].

    PubMed

    Bagotskaia, M S; Smirnova, A A; Zorina, Z A

    2013-01-01

    Eight hooded crows (Corvus cornix L.) were tested for their ability to use a piston (a stick with two attached clear plates between which the food is enclosed such that moving the stick would move the food) to get the reward out of a transparent tube avoiding a trap. Six out of eight crows learned to use a piston to extract a food reward from a transparent non-trap tube. One out of these six birds successfully performed the task in which it had to avoid a trap to retrieve a reward, in the first trial showing spontaneous comprehending of the task structure. Four crows learned to perform this task using the trial-and-error method. To find out a mechanism these crows used to perform the task, birds were presented with two transfer tasks (tests) in which we changed the relative positions of components in the apparatus. We found out that crows performed transfer tasks using rather concrete rules than immediate estimation of the relative positions of the components in the apparatus. PMID:23659111

  3. Skill Components of Task Analysis

    ERIC Educational Resources Information Center

    Adams, Anne E.; Rogers, Wendy A.; Fisk, Arthur D.

    2013-01-01

    Some task analysis methods break down a task into a hierarchy of subgoals. Although an important tool of many fields of study, learning to create such a hierarchy (redescription) is not trivial. To further the understanding of what makes task analysis a skill, the present research examined novices' problems with learning Hierarchical Task

  4. Task Analysis: A Proactive Paradigm.

    ERIC Educational Resources Information Center

    Cipriano, Robert E.

    A sequential and developmental curriculum design is conceptualized, based on task analysis. Task analysis is a detailed inquiry into actions undertaken in performing specific tasks or jobs. Baseline data form a database on which education and training programs are designed, produced, and evaluated. The following are sources of information for task

  5. A New Atom Trap The Annular Shell Atom Trap (ASAT)

    E-print Network

    Pilloff, H S; Pilloff, Herschel S.; Horbatsch, Marko

    2002-01-01

    In the course of exploring some aspects of atom guiding in a hollow, optical fiber, a small negative potential energy well was found just in front of the repulsive or guiding barrier. This results from the optical dipole and the van der Waals potentials. The ground state for atoms bound in this negative potential well was determined by numerically solving the Schrodinger eq. and it was found that this negative well could serve as an atom trap. This trap is referred to as the Annular Shell Atom Trap or ASAT because of the geometry of the trapped atoms which are located in the locus of points defining a very thin annular shell just in front of the guiding barrier. A unique feature of the ASAT is the compression of the atoms from the entire volume to the volume of the annular shell resulting in a very high density of atoms in this trap. This trap may have applications to very low temperatures using evaporative cooling and possibly the formation of BEC. Finally, a scheme is discussed for taking advantage of the d...

  6. Microprocessor multi-task monitor

    SciTech Connect

    Ludemann, C.A.

    1983-01-01

    This paper describes a multi-task monitor program for microprocessors. Although written for the Intel 8085, it incorporates features that would be beneficial for implementation in other microprocessors used in controlling and monitoring experiments and accelerators. The monitor places permanent programs (tasks) arbitrarily located throughout ROM in a priority ordered queue. The programmer is provided with the flexibility to add new tasks or modified versions of existing tasks, without having to comply with previously defined task boundaries or having to reprogram all of ROM. Scheduling of tasks is triggered by timers, outside stimuli (interrupts), or inter-task communications. Context switching time is of the order of tenths of a milllisecond.

  7. Trapped Quintessential Inflation

    E-print Network

    J. C. Bueno Sanchez; K. Dimopoulos

    2006-05-26

    Quintessential inflation is studied using a string modulus as the inflaton - quintessence field. The modulus begins its evolution at the steep part of its scalar potential, which is due to non-perturbative effects (e.g. gaugino condensation). It is assumed that the modulus crosses an enhanced symmetry point (ESP) in field space. Particle production at the ESP temporarily traps the modulus resulting in a brief period of inflation. More inflation follows, due to the flatness of the potential, since the ESP generates either an extremum (maximum or minimum) or a flat inflection point in the scalar potential. Eventually, the potential becomes steep again and inflation is terminated. After reheating the modulus freezes due to cosmological friction at a large value, such that its scalar potential is dominated by contributions due to fluxes in the extra dimensions or other effects. The modulus remains frozen until the present, when it can become quintessence and account for the dark energy necessary to explain the observed accelerated expansion.

  8. Data Center Tasking.

    ERIC Educational Resources Information Center

    Temares, M. Lewis; Lutheran, Joseph A.

    Operations tasking for data center management is discussed. The original and revised organizational structures of the data center at the University of Miami are also described. The organizational strategy addresses the functions that should be performed by the data center, anticipates the specialized skills required, and addresses personnel…

  9. Embodied Task Dynamics

    ERIC Educational Resources Information Center

    Simko, Juraj; Cummins, Fred

    2010-01-01

    Movement science faces the challenge of reconciling parallel sequences of discrete behavioral goals with observed fluid, context-sensitive motion. This challenge arises with a vengeance in the speech domain, in which gestural primitives play the role of discrete goals. The task dynamic framework has proved effective in modeling the manner in which…

  10. Hydrodynamic enhanced dielectrophoretic particle trapping

    DOEpatents

    Miles, Robin R.

    2003-12-09

    Hydrodynamic enhanced dielectrophoretic particle trapping carried out by introducing a side stream into the main stream to squeeze the fluid containing particles close to the electrodes producing the dielelectrophoretic forces. The region of most effective or the strongest forces in the manipulating fields of the electrodes producing the dielectrophoretic forces is close to the electrodes, within 100 .mu.m from the electrodes. The particle trapping arrangement uses a series of electrodes with an AC field placed between pairs of electrodes, which causes trapping of particles along the edges of the electrodes. By forcing an incoming flow stream containing cells and DNA, for example, close to the electrodes using another flow stream improves the efficiency of the DNA trapping.

  11. Evaporative Cooling of Trapped Atoms

    Microsoft Academic Search

    Wolfgang Ketterle; N. J. Van Druten

    1996-01-01

    This report discusses the following topics on evaporative cooling of trapped atoms: Theoretical models for evaporative cooling; the role of collisions for real atoms; experimental techniques and summary of evaporative cooling experiments. 166 refs., 6 figs., 3 tabs.

  12. Gated charged-particle trap

    DOEpatents

    Benner, W.H.

    1999-03-09

    The design and operation of a new type of charged-particle trap provides simultaneous measurements of mass, charge, and velocity of large electrospray ions. The trap consists of a detector tube mounted between two sets of center-bored trapping plates. Voltages applied to the trapping plates define symmetrically-opposing potential valleys which guide axially-injected ions to cycle back and forth through the charge-detection tube. A low noise charge-sensitive amplifier, connected to the tube, reproduces the image charge of individual ions as they pass through the detector tube. Ion mass is calculated from measurement of ion charge and velocity following each passage through the detector. 5 figs.

  13. Mini ion trap mass spectrometer

    DOEpatents

    Dietrich, Daniel D. (Livermore, CA); Keville, Robert F. (Valley Springs, CA)

    1995-01-01

    An ion trap which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10.sup.9 and commercial mass spectrometers requiring 10.sup.4 ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products.

  14. Mini ion trap mass spectrometer

    DOEpatents

    Dietrich, D.D.; Keville, R.F.

    1995-09-19

    An ion trap is described which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10{sup 9} and commercial mass spectrometers requiring 10{sup 4} ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products. 10 figs.

  15. Analysis of task analysis procedures

    Microsoft Academic Search

    David H. Jonassen; Wallace H. Hannum

    1986-01-01

    For the new developer, deciding which task analysis procedures to use can be confusing. In this article, we describe the five\\u000a functions comprising the task analysis process: inventorying, describing, selecting, sequencing, and analyzing tasks. We then\\u000a describe some critical distinctions in the task analysis process: micro\\/macro level, top-down\\/bottom-up, and job\\/learning\\u000a task analysis. We then combine the functions and distinctions in

  16. The Elimination of Steam Traps

    E-print Network

    Dickman, F.

    -staged modified venturi nozzles to replace steam traps. Afterseven years of industrial experience the results are clear. Fuel reduction is in the range of 12-54%. Maintenance is virtually non existant. Use-life is unmatched. The primary advantages... venturi nozzle. Further design improvements led to ad ditional new patents pending, both related and unrelated to steam trap technology. FIGURE 4 - A LASTING SOLUTION 28 A patented development of Engineering Resources, Inc., the system employs multi...

  17. Optical trapping of silver nanoplatelets.

    PubMed

    Messina, E; Donato, M G; Zimbone, M; Saija, R; Iatì, M A; Calcagno, L; Fragalà, M E; Compagnini, G; D'Andrea, C; Foti, A; Gucciardi, P G; Maragò, O M

    2015-04-01

    Optical trapping of silver nanoplatelets obtained with a simple room temperature chemical synthesis technique is reported. Trap spring constants are measured for platelets with different diameters to investigate the size-scaling behaviour. Experimental data are compared with models of optical forces based on the dipole approximation and on electromagnetic scattering within a T-matrix framework. Finally, we discuss applications of these nanoplatelets for surface-enhanced Raman spectroscopy. PMID:25968710

  18. MacWilliams type equivalence relations

    E-print Network

    Choi, Soohak; Kim, Hyun Kwang; Oh, Dong Yeol

    2012-01-01

    Let $\\mathbb{P}$ be a poset on $[n]$ and $E$ an equivalence relation on the set of order ideals of $\\mathbb{P}$. First we introduce a new weight distribution, called the $E$-weight distribution, which generalizes the $\\mathbb{P}$-weight distribution. Next we introduce the class of equivalence relations so called the MacWilliams-type equivalence relations which enables us to study the Macwilliams duality for $E$-weight distributions. We impose a particular condition on an equivalence relation, and finally prove that this condition is an equivalent condition to become a MacWilliams-type equivalence relation. We also drive the MacWilliams duality for the $E$-weight distributions when $E$ satisfies the conditions mentioned above.

  19. Trapping of neutrinos in extremely compact stars

    E-print Network

    Zdenek Stuchlik; Martin Urbanec; Gabriel Torok; Stanislav Hledik; Jan Hladik

    2007-01-11

    Trapping of neutrinos in extremely compact stars containing trapped null geodesics is studied. We calculated the ratio of produced to trapped neutrinos in the simplest model of uniform density stars. This gives the upper limit on trapping coefficients in real objects.

  20. Accommodation in Astigmatic Children During Visual Task Performance

    PubMed Central

    Harvey, Erin M.; Miller, Joseph M.; Apple, Howard P.; Parashar, Pavan; Twelker, J. Daniel; Crescioni, Mabel; Davis, Amy L.; Leonard-Green, Tina K.; Campus, Irene; Sherrill, Duane L.

    2014-01-01

    Purpose. To determine the accuracy and stability of accommodation in uncorrected children during visual task performance. Methods. Subjects were second- to seventh-grade children from a highly astigmatic population. Measurements of noncycloplegic right eye spherical equivalent (Mnc) were obtained while uncorrected subjects performed three visual tasks at near (40 cm) and distance (2 m). Tasks included reading sentences with stimulus letter size near acuity threshold and an age-appropriate letter size (high task demands) and viewing a video (low task demand). Repeated measures ANOVA assessed the influence of astigmatism, task demand, and accommodative demand on accuracy (mean Mnc) and variability (mean SD of Mnc) of accommodation. Results. For near and distance analyses, respectively, sample size was 321 and 247, mean age was 10.37 (SD 1.77) and 10.30 (SD 1.74) years, mean cycloplegic M was 0.48 (SD 1.10) and 0.79 diopters (D) (SD 1.00), and mean astigmatism was 0.99 (SD 1.15) and 0.75 D (SD 0.96). Poor accommodative accuracy was associated with high astigmatism, low task demand (video viewing), and high accommodative demand. The negative effect of accommodative demand on accuracy increased with increasing astigmatism, with the poorest accommodative accuracy observed in high astigmats (?3.00 D) with high accommodative demand/high hyperopia (1.53 D and 2.05 D of underaccommodation for near and distant stimuli, respectively). Accommodative variability was greatest in high astigmats and was uniformly high across task condition. No/low and moderate astigmats showed higher variability for the video task than the reading tasks. Conclusions. Accuracy of accommodation is reduced in uncorrected children with high astigmatism and high accommodative demand/high hyperopia, but improves with increased visual task demand (reading). High astigmats showed the greatest variability in accommodation. PMID:25103265

  1. Classroom applications of stimulus equivalence technology

    Microsoft Academic Search

    Robert Stromer; Harry A. Mackay; Lawrence T. Stoddard

    1992-01-01

    We review basic concepts and methods of stimulus equivalence research and suggest applications in teaching rudimentary language arts skills in the classroom. We describe methods of establishing equivalence-based networks of matching-to-sample, writing, and naming performances. The methods may be used as a supplement to classroom instruction to assess whether standard curriculum-based approaches establish such integrated networks. Methods derived from equivalence

  2. Analysis of affinely equivalent Boolean functions

    Microsoft Academic Search

    Qingshu Meng; Huanguo Zhang; Min Yang; Zhangyi Wang

    2007-01-01

    By some basic transforms and invariant theory, we give two results: 1) an algorithm, which can be used to judge if two Boolean\\u000a functions are affinely equivalent and to obtain the equivalence relationship if they are equivalent. This is useful in studying\\u000a Boolean functions and in engineering. For example, we classify all 8-variable homogeneous bent functions of degree 3 into

  3. Universal collisional activation ion trap mass spectrometry

    DOEpatents

    McLuckey, S.A.; Goeringer, D.E.; Glish, G.L.

    1993-04-27

    A universal collisional activation ion trap comprises an ion trapping means containing a bath gas and having connected thereto a noise signal generator. A method of operating a universal collisional activation ion trap comprises the steps of: providing an ion trapping means; introducing into the ion trapping means a bath gas; and, generating a noise signal within the ion trapping means; introducing into the ion trapping means a substance that, when acted upon by the noise signal, undergoes collisional activation to form product ions.

  4. Collisional trap losses of cold magnetically trapped Br atoms

    NASA Astrophysics Data System (ADS)

    Lam, J.; Rennick, C. J.; Softley, T. P.

    2014-12-01

    Near-threshold photodissociation of Br2 from a supersonic beam produces slow bromine atoms that are trapped in the magnetic-field minimum formed between two opposing permanent magnets. Here we quantify the dominant trap-loss rate due to collisions with two sources of residual gas: the background limited by the vacuum chamber base pressure and the carrier gas during the supersonic gas pulse. The loss rate due to collisions with residual Ar in the background follows pseudo-first-order kinetics and the bimolecular rate coefficient for collisional loss from the trap is determined by measurement of this rate as a function of the background Ar pressure. This rate coefficient is smaller than the total elastic collision rate coefficient, as it only samples those collisions that lead to trap loss, and is determined to be =(1.12 ±0.09 ) ×10-9cm3s-1 . The calculated differential cross section can be used with this value to estimate a trap depth of 293 ±24 mK . Carrier-gas collisions occur only during the tail of the supersonic beam pulse. Using the differential cross section verified by the background-gas collision measurements provides an estimate of the peak molecular-beam density of (3.0 ±0.3 ) ×1013cm-3 , in good agreement with the prediction of a simple supersonic expansion model. Finally, we estimate the trap-loss rate due to Majorana transitions to be negligible, owing to the relatively large trapped-atom phase-space volume.

  5. Live trapping of hawks and owls

    USGS Publications Warehouse

    Stewart, R.E.; Cope, J.B.; Robbins, C.S.

    1945-01-01

    1. Hawks of six species (80 individuals) and owls of five species (37 individuals) were trapped for banding from November 1, 1943, to. May 26,1944. 2. In general, pole traps proved better than hand-operated traps or automatic traps using live bait. 3. Verbail pole traps proved very efficient, and were much more humane than padded steel traps because they rarely injured a captured bird. 4: Unbaited Verbail traps took a variety of raptors, in rough proportion to their local abundance, although slightly more of beneficial species were caught than of harmful types. 5. Hawks and owls were retrapped more readily in Verbail traps than in other types tried. 6. The number of song birds caught in Verbail traps was negligible. 7. Crows and vultures were not taken in Verbail traps, but possibly could be caught with bait.

  6. Effect of bait in live trapping Peromyscus

    USGS Publications Warehouse

    Stickel, L.F.

    1948-01-01

    SUMMARY: Evidence from live trapping tests indicated that Peromyscus leucopus did not leave their home ranges because of the attraction of trap bait in nearby areas. A trap line down the center of a heavily live-trapped area caught as many mice before the area trapping as afterward. Thus, there was reason to believe that the area trapping did not serve to pre-bait the mice. Two unbaited lines of live traps caught an equal number of Peromyscus. When one line was baited with rolled oats and peanut butter the efficiency of the traps was improved to the extent that the baited line captured more than twice as many mice as the unbaited line. It is concluded that for the species and habitat tested it is safe to make population calculations based on the assumption that the animals remain within their home ranges and do not tend to move into the trapped area because of the attraction of the trap bait.

  7. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents § 110.20-1...necessary, the Marine Safety Center may require engineering evaluations and tests to demonstrate the...

  8. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents § 110.20-1...necessary, the Marine Safety Center may require engineering evaluations and tests to demonstrate the...

  9. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents § 110.20-1...necessary, the Marine Safety Center may require engineering evaluations and tests to demonstrate the...

  10. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents § 110.20-1...necessary, the Marine Safety Center may require engineering evaluations and tests to demonstrate the...

  11. Sticky Traps for Large Scale House Fly (Diptera: Muscidae) Trapping in New York Poultry Facilities1

    E-print Network

    Kaufman, Phillip E.

    Sticky Traps for Large Scale House Fly (Diptera: Muscidae) Trapping in New York Poultry Facilities1 traps were evaluated under field conditions in two commercial high-rise, caged-layer poultry facilities-layerpoultry facilities. One side of each poultry facil- ity received traps with 1.2 m of exposed adhesive,whereas traps

  12. Einstein's equivalence principle in cosmology

    NASA Astrophysics Data System (ADS)

    Kopeikin, Sergei

    We study physical consequences of the Einstein equivalence principle (EEP) for a Hubble observer in FLRW universe. We introduce the local inertial coordinates with the help of a special conformal transformation. The local inertial metric is Minkowski-flat and materialized by a congruence of time-like geodesics of static observers. The static observers are equipped with the ideal clocks measuring the proper time that is synchronized with the clocks of the Hubble observer. The local inertial metric is used for physical measurements of spacetime intervals with the ideal clocks and rulers. The special conformal transformation preserves null geodesics but does not keep invariant time-like geodesics. Moreover, it makes the rate of the local time coordinate dependent on velocity of the particle which makes impossible to rich the uniform parameterization of the world lines of static observers and light geodesics with a single parameter - they differ by the conformal factor of FLRW metric. It tells us that the metric on the light cone is not Minkowski-flat but depends on the scale factor of FLRW universe and it can be interpreted as a weak violation of EEP for photons. The importance of this violation for gravitational physics is that some of local experiments conducted with freely-propagating electromagnetic waves may be sensitive to the Hubble expansion. We show that the Hubble constant H can be measured within the solar system by means of high-precision spacecraft Doppler tracking as a blue shift of frequency of radio waves circulating in the Earth-spacecraft radio link. We also analyze the behavior of the standing wave in a microwave resonator and show that the standing wave is insensitive to the Hubble expansion.

  13. A comparison of two commercial mosquito traps for the capture of malaria vectors in northern belize, central america.

    PubMed

    Wagman, Joseph; Grieco, John P; Bautista, Kim; Polanco, Jorge; Briceño, Ireneo; King, Russell; Achee, Nicole L

    2014-09-01

    To achieve maximum success from any vector control intervention, it is critical to identify the most efficacious tools available. The principal aim of this study was to evaluate the efficacy of 2 commercially available adult mosquito traps for capturing Anopheles albimanus and An. vestitipennis, 2 important malaria vectors in northern Belize, Central America. Additionally, the impact of outdoor baited traps on mosquito entry into experimental huts was assessed. When operated outside of human-occupied experimental huts, the Centers for Disease Control and Prevention (CDC) miniature light trap, baited with human foot odors, captured significantly greater numbers of female An. albimanus per night (5.1 ± 1.9) than the Biogents Sentinel™ trap baited with BG-Lure™ (1.0 ± 0.2). The 2 trap types captured equivalent numbers of female An. vestitipennis per night, 134.3 ± 45.6 in the CDC trap and 129.6 ± 25.4 in the Sentinel trap. When compared to a matched control hut using no intervention, the use of baited CDC light traps outside an experimental hut did not impact the entry of An. vestitipennis into window interception traps, 17.1 ± 1.3 females per hour in experimental huts vs. 17.2 ± 1.4 females per hour in control huts. However, the use of outdoor baited CDC traps did significantly decrease the entry of An. albimanus into window interception traps from 3.5 ± 0.5 females per hour to 1.9 ± 0.2 females per hour. These results support existing knowledge that the underlying ecological and behavioral tendencies of different Anopheles species can influence trap efficacy. Furthermore, these findings will be used to guide trap selection for future push-pull experiments to be conducted at the study site. PMID:25843092

  14. Foraging decisions and behavioural flexibility in trap-building predators: a review.

    PubMed

    Scharf, Inon; Lubin, Yael; Ovadia, Ofer

    2011-08-01

    Foraging theory was first developed to predict the behaviour of widely-foraging animals that actively search for prey. Although the behaviour of sit-and-wait predators often follows predictions derived from foraging theory, the similarity between these two distinct groups of predators is not always obvious. In this review, we compare foraging activities of trap-building predators (mainly pit-building antlions and web-building spiders), a specific group of sit-and-wait predators that construct traps as a foraging device, with those of widely-foraging predators. We refer to modifications of the trap characteristics as analogous to changes in foraging intensity. Our review illustrates that the responses of trap-building and widely-foraging predators to different internal and external factors, such as hunger level, conspecific density and predation threat are quite similar, calling for additional studies of foraging theory using trap-building predators. In each chapter of this review, we summarize the response of trap-building predators to a different factor, while contrasting it with the equivalent response characterizing widely-foraging predators. We provide here evidence that the behaviour of trap-building predators is not stereotypic or fixed as was once commonly accepted, rather it can vary greatly, depending on the individual's internal state and its interactions with external environmental factors. PMID:21062400

  15. Task-specific effects of reward on task switching.

    PubMed

    Umemoto, Akina; Holroyd, Clay B

    2015-07-01

    Although cognitive control and reinforcement learning have been researched extensively over the last few decades, only recently have studies investigated their interrelationship. An important unanswered question concerns how the control system decides what task to execute and how vigorously to carry out the task once selected. Based on a recent theory of control formulated according to principles of hierarchical reinforcement learning, we asked whether rewards can affect top-down control over task performance at the level of task representation. Participants were rewarded for correctly performing only one of two tasks in a standard task-switching experiment. Reaction times and error rates were lower for the reinforced task compared to the non-reinforced task. Moreover, the switch cost in error rates for the non-reinforced task was significantly larger compared to the reinforced task, especially for trials in which the imperative stimulus afforded different responses for the two tasks, resulting in a "non-paradoxical" asymmetric switch cost. These findings suggest that reinforcement at the task level resulted in greater application of top-down control rather than in stronger stimulus-response pathways for the rewarded task. PMID:24984832

  16. Extrinsic charge traps in disordered organic materials

    NASA Astrophysics Data System (ADS)

    Lin, Liang-Bih; Cheng, Chi-Wen; Dai, Chi-An; Lee, Yuan-Pern

    2012-10-01

    The effects of p-diethylaminobenzaldehyde diphenylhydrazone, a 0.22 eV trap, on the charge transport properties of disordered organic materials consisted of a mixture of N,N'-diphenyl N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine and polycarbonate are described. Trap-perturbed, trap-limited, and trap-controlled (trap-to-trap) transports were observed, where the trap is less effective at very low trap concentrations but appears to have increasing trap depth with respect to the concentration increase in the trap-limited regime. Most photocurrent transients showed non-dispersive transport behaviors; however, some were dispersive, especially at low electric fields or near the cross-over region between the trap-limited and trap-controlled transports. Field dependency of the mobilites at the trap-limited regime is higher than that of the trap-controlled regime, suggesting some type of superexchange phenomenon or field induced detrapping for the latter transport. For most known systems, charge transport reaches at a minimum mobility that is higher than anticipated from the trap depth. Analysis of the experimental results by theoretical models based on molecular crystals and disordered materials strongly suggests the influence of disorder but only gives qualitative agreements.

  17. Solar Thermal Task Analysis

    NSDL National Science Digital Library

    The Advanced Technology Environmental and Energy Center (ATEEC) has provided this document which includes an overview of objectives and task analysis for individuals installing solar water and pool heating systems. Areas of expertise include working safely with solar hot water and pool heating systems, identifying systems and their components and installing equipment. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

  18. HiTrapTM Phenyl FF (high sub), HiTrap Phenyl FF (low sub), HiTrap Phenyl HP, HiTrap Butyl FF, HiTrap Butyl-S FF, and HiTrap Octyl FF are prepacked 1 ml and 5 ml,

    E-print Network

    Lebendiker, Mario

    HiTrapTM Phenyl FF (high sub), HiTrap Phenyl FF (low sub), HiTrap Phenyl HP, HiTrap Butyl FF, Hi. Instructions 11-0034-52 AB HiTrap HIC columns GE Healthcare HiTrap HIC Columns HiTrap Phenyl FF (high sub), 1 ml and 5 ml HiTrap Phenyl FF (low sub), 1 ml and 5 ml HiTrap Phenyl HP, 1 ml and 5 ml HiTrap Butyl FF

  19. Trapping biases of Culex torrentium and Culex pipiens revealed by comparison of captures in CDC traps, ovitraps, and gravid traps.

    PubMed

    Hesson, Jenny C; Ignell, Rickard; Hill, Sharon R; Östman, Örjan; Lundström, Jan O

    2015-06-01

    We evaluate three trapping methods for their effectiveness at capturing Culex pipiens and Culex torrentium, both enzootic vectors of bird-associated viruses in Europe. The comparisons, performed in two regions in Sweden, were among CDC traps baited with carbon dioxide, gravid traps, and ovitraps baited with hay infusion. The proportions of the two Culex species in a catch differed between trap types, with CDC traps catching a lower proportion of Cx. torrentium than both gravid traps and ovitraps. Between gravid traps and ovitraps, there was no difference in the proportions of the two species. The results indicate that Cx. torrentium may go undetected or underestimated compared to Cx. pipiens when using carbon dioxide baited CDC traps. The new insight of trap bias presented here adds an important dimension to consider when investigating these vectors of bird-associated viruses in the field. PMID:26047196

  20. Some Studies of Pulse Transformer Equivalent Circuits

    Microsoft Academic Search

    C. K. Hadlock; D. Lebell

    1951-01-01

    A pulse transformer equivalent circuit is synthesized from data obtained by direct test on a typical pulse transformer. The differential equations for the equivalent circuit are solved by means of a mechanical differential analyzer for a variety of circuit constant values. Wave forms of transformer output voltage as obtained from the differential analyzer are of assistance in the design of

  1. Equivalence and optimization of absorbing boundary conditions

    Microsoft Academic Search

    Weiliang Yuan; Qinxi Chu; Changhong Liang

    1998-01-01

    Four types of absorbing boundary conditions (ABC) widely used in finite-difference time-domain (FDTD) simulations are discussed from the point of view of their equivalence. They include Mur's (1981) ABC, dispersive ABC, Liao's (1986) ABC and Higdon's (1986) operator, and an analytical expression of Liao's ABC is given. These ABCs are essentially equivalent and can be embodied by an analytical equation

  2. PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS

    E-print Network

    Heinzer, William

    PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS+. It is known that if I and J are projectively equivalent, then the set* * ReesI of Rees valuation rings of I is equal to the set ReesJ of Rees valuation rings of * *J and the values of I and J

  3. PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS

    E-print Network

    Heinzer, William

    PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS Catalin Ciuperca, William J. Heinzer, Louis J IN+. It is known that if I and J are projectively equivalent, then the set Rees I of Rees valuation rings of I is equal to the set Rees J of Rees valuation rings of J and the values of I and J

  4. PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS

    E-print Network

    Heinzer, William

    PROJECTIVELY EQUIVALENT IDEALS AND REES VALUATIONS Catalin Ciuperca, William J. Heinzer, Louis J, j # IN + . It is known that if I and J are projectively equivalent, then the set Rees I of Rees valuation rings of I is equal to the set Rees J of Rees valuation rings of J and the values of I and J

  5. Countable Borel Equivalence Relations III Simon Thomas

    E-print Network

    Thomas, Simon

    Countable Borel Equivalence Relations III Simon Thomas Rutgers University 26th November 2012 Simon) = the unique h H such that h · f(x) = f(g · x). Simon Thomas (Rutgers University) Rutgers Logic Seminar 26th). Simon Thomas (Rutgers University) Rutgers Logic Seminar 26th November 2012 #12;Cocycle equivalence - f

  6. Countable Borel Equivalence Relations II Simon Thomas

    E-print Network

    Andrews, Peter B.

    Countable Borel Equivalence Relations II Simon Thomas Rutgers University 17th November 2007 Simon. the Turing equivalence relation. Simon Thomas (Rutgers University) Appalachian Set Theory Workshop 17th extent does the data (X, EX G ) "remember" G and its action on X? Simon Thomas (Rutgers University

  7. Countable Borel Equivalence Relations II Simon Thomas

    E-print Network

    Thomas, Simon

    Countable Borel Equivalence Relations II Simon Thomas Rutgers University 12th November 2012 Simon. the Turing equivalence relation. Simon Thomas (Rutgers University) Rutgers Logic Seminar 12th November 2012 the data (X, EX G ) "remember" both the group G and its action on X? Simon Thomas (Rutgers University

  8. When are origin and destination regimes equivalent?

    Microsoft Academic Search

    Ben Lockwood; DAVID DE MEZA; Gareth D. Myles

    1994-01-01

    A series of equivalence results are established which show that a switch from a destination regime of commodity taxation to an origin regime has no real effects. These significantly generalize those in the existing literature. Assuming uniformity of taxes within each country, equivalence applies (1) in a general competitive economy with an arbitrary (finite) number of goods and factors of

  9. ACQUIRED EQUIVALENCE CHANGES STIMULUS REPRESENTATIONS , D. SHOHAMY

    E-print Network

    Shohamy, Daphna

    ACQUIRED EQUIVALENCE CHANGES STIMULUS REPRESENTATIONS M. MEETER 1 , D. SHOHAMY 2 , AND C.E. MYERS 3 UNIVERSITY 3 DEPT. OF PSYCHOLOGY, RUTGERS UNIVERSITY Acquired equivalence is a paradigm in which, including changes in stimulus representations, either in the form of added associations or a change

  10. Tau-Equivalence and Equipercentile Equating.

    ERIC Educational Resources Information Center

    Yen, Wendy M.

    1983-01-01

    Tau-equivalence means that two tests produce equal true scores for individuals but that the distribution of errors for the tests could be different. This paper examines the effect of performing equipercentile equating techniques on tau-equivalent tests. (JKS)

  11. Pre-Task Syntactic Priming and Focused Task Design

    ERIC Educational Resources Information Center

    Boston, Jeremy S.

    2010-01-01

    Focused tasks engage learners in using language for communication and in addition have a specific predetermined linguistic focus in mind. The difficulty in designing focused tasks is that many meanings can be articulated using more than one language form, making it difficult to design tasks which induce learner use of a specific target form. This…

  12. Backward Blocking and Interference between Cues Are Empirically Equivalent in Non-Causally Framed Learning Tasks

    ERIC Educational Resources Information Center

    Luque, David; Moris, Joaquin; Orgaz, Cristina; Cobos, Pedro L.; Matute, Helena

    2011-01-01

    Backward blocking (BB) and interference between cues (IbC) are cue competition effects produced by very similar manipulations. In a standard BB design, both effects might occur simultaneously, which implies a potential problem for studying BB. In the present study with humans, the magnitude of both effects was compared using a non-causal scenario…

  13. Functional Equivalence in Children: Derived Stimulus–Response and Stimulus–Stimulus Relations

    Microsoft Academic Search

    Paul M. Smeets; Dermot Barnes; Bryan Roche

    1997-01-01

    The present study investigated the simultaneous occurrence of emergent stimulus–response relations (functional equivalence) and stimulus–stimulus relations (stimulus equivalence). After being pretrained and tested on two symbolic match-to-sample tasks (X1-Y1, X2-Y2), 20 4- and 5-year-old children were trained to emit specified responses to pairs of stimuli (A1-R1, B1-R1, A2-R2, B2-R2) in one setting (original training) and to emit other responses to

  14. Control equivalent turbulence input model for the UH-60 helicopter

    NASA Astrophysics Data System (ADS)

    Lusardi, Jeff

    Flight test data from a UH-60 Black Hawk helicopter hovering in the atmospheric turbulence downwind of a large cube-shaped hanger on a wind day were collected. An inverse modeling method was used to extract the control inputs that are required to replicate the portion of the aircraft response attributable to atmospheric disturbances from the flight-test data. Based on the extracted control inputs, a parametric Control Equivalent Turbulence Input (CETI) model comprised of white-noise driven filters that have a Dryden-type form and are scalable for varying levels of turbulence were developed. The outputs of the filters are disturbance time histories that sum with the pilot's inputs, to replicate the effects of atmospheric turbulence in calm atmospheric conditions. A ground-based piloted simulation study was conducted in the NASA/Ames Vertical Motion Simulator (VMS) comparing the empirically based CETI model with flight-test data and with a complex Simulation Of Rotor Blade Element Turbulence (SORBET) model. Two test pilots performed precision hover tasks with increasing levels of simulated turbulence from both the CETI and SORBET models. The results of the simulation study showed good pilot acceptance of the CETI model and provided a good level of validation of the more complex rotating frame turbulence model. An in-flight simulation study was conducted on the Rotorcraft Aircrew Systems Concepts Airborne Laboratory (RASCAL) UH-60 helicopter using the CETI model. Two test pilots performed a precision hover task on calm days with simulated CETI turbulence. Aircraft response metrics showed good agreement between a hover task with CETI simulated turbulence and the same task in atmospheric turbulence. Both pilots commented that the RASCAL's response to CETI turbulence was similar to the response hovering downwind of the large cube-shaped hangar on a windy day. The CETI model developed in this dissertation simulates turbulence by generating equivalent disturbance inputs to the control system of the helicopter. This makes the CETI model suitable for use with any helicopter math model to study the effects of turbulence on handling qualities and for use in designing control systems to reject atmospheric turbulence.

  15. 4.NF Explaining Fraction Equivalence with Pictures

    NSDL National Science Digital Library

    2012-06-25

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: The rectangle below has length 1. What fraction does the shaded part represent? The rectangle below has the same length as the rectangle above. What fr...

  16. Complex plane analysis of trapping phenomena in zinc oxide based varistor grain boundaries

    NASA Astrophysics Data System (ADS)

    Alim, Mohammad A.; Seitz, Martin A.; Hirthe, Richard W.

    1988-04-01

    The origin of the frequency-dependent Mott-Schottky behavior observed in a wide range of ZnO-Bi2O3 varistor systems has been investigated. Lumped parameter/complex plane analysis of two-probe ac electrical data indicates that several trapping relaxations contribute to the measured MOV grain-boundary admittance in the frequency range, 10-2 Hz?f?107 Hz. Furthermore, this approach allows the development of an equivalent circuit representation which incorporates these trapping phenomena in a systematic manner.

  17. Task Constraints on Affordance Boundaries

    Microsoft Academic Search

    Stacy M. Lopresti-Goodman; Michael J. Richardson; Reuben M. Baron; Claudia Carello; Kerry L. Marsh

    Abstract The actualization of a simple affordance task—grasping and moving,wooden,planks of different sizes using either one or two hands—was,assessed inthe context of task-relevant (plank sequence, plank presentation speed) and task-irrelevant (cognitive load)

  18. TASK: Let's Have a Party!

    ERIC Educational Resources Information Center

    Rees, James

    2012-01-01

    In this article, the author describes a creative way to demystify contemporary art for students. TASK is artist Oliver Herring's creation, where participants actively interpret instructions found on little pieces of paper--what he calls "tasks." An art classroom has all the key ingredients for a TASK event: (1) people; (2) materials; (3) space;…

  19. Task-oriented rehabilitation robotics.

    PubMed

    Schweighofer, Nicolas; Choi, Younggeun; Winstein, Carolee; Gordon, James

    2012-11-01

    Task-oriented training is emerging as the dominant and most effective approach to motor rehabilitation of upper extremity function after stroke. Here, the authors propose that the task-oriented training framework provides an evidence-based blueprint for the design of task-oriented robots for the rehabilitation of upper extremity function in the form of three design principles: skill acquisition of functional tasks, active participation training, and individualized adaptive training. The previous robotic systems that incorporate elements of task-oriented trainings are then reviewed. Finally, the authors critically analyze their own attempt to design and test the feasibility of a TOR robot, ADAPT (Adaptive and Automatic Presentation of Tasks), which incorporates the three design principles. Because of its task-oriented training-based design, ADAPT departs from most other current rehabilitation robotic systems: it presents realistic functional tasks in which the task goal is constantly adapted, so that the individual actively performs doable but challenging tasks without physical assistance. To maximize efficacy for a large clinical population, the authors propose that future task-oriented robots need to incorporate yet-to-be developed adaptive task presentation algorithms that emphasize acquisition of fine motor coordination skills while minimizing compensatory movements. PMID:23080042

  20. Analysis of Task Analysis Procedures.

    ERIC Educational Resources Information Center

    Jonassen, David H.; Hannum, Wallace H.

    1986-01-01

    Describes functions comprising task analysis process--inventory, description, selection, sequencing, and analysis--and reviews distinctions between the micro/macro level, top-down/bottom-up, and job/learning task analysis processes. These functions and distinctions are combined into a quasi-algorithm suggesting which of 30 task analysis procedures…

  1. The cognitive task analysis system

    Microsoft Academic Search

    June Wei

    2000-01-01

    The objective of this dissertation is to develop and validate a cognitive job and task analysis methodology that not only analyzes jobs and tasks, but also provides a mechanism for improving cognitive job and task performance. It provides a scientific methodology for matching what individuals wish to do in a job and the actual job content for job (re)design. Four

  2. Maximally Expressive Task Modeling

    NASA Technical Reports Server (NTRS)

    Japp, John; Davis, Elizabeth; Maxwell, Theresa G. (Technical Monitor)

    2002-01-01

    Planning and scheduling systems organize "tasks" into a timeline or schedule. The tasks are defined within the scheduling system in logical containers called models. The dictionary might define a model of this type as "a system of things and relations satisfying a set of rules that, when applied to the things and relations, produce certainty about the tasks that are being modeled." One challenging domain for a planning and scheduling system is the operation of on-board experiment activities for the Space Station. The equipment used in these experiments is some of the most complex hardware ever developed by mankind, the information sought by these experiments is at the cutting edge of scientific endeavor, and the procedures for executing the experiments are intricate and exacting. Scheduling is made more difficult by a scarcity of space station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling space station experiment operations calls for a "maximally expressive" modeling schema. Modeling even the simplest of activities cannot be automated; no sensor can be attached to a piece of equipment that can discern how to use that piece of equipment; no camera can quantify how to operate a piece of equipment. Modeling is a human enterprise-both an art and a science. The modeling schema should allow the models to flow from the keyboard of the user as easily as works of literature flowed from the pen of Shakespeare. The Ground Systems Department at the Marshall Space Flight Center has embarked on an effort to develop a new scheduling engine that is highlighted by a maximally expressive modeling schema. This schema, presented in this paper, is a synergy of technological advances and domain-specific innovations.

  3. Langmuir waves from trapped superthermal electrons

    SciTech Connect

    Wentzel, D.G.

    1985-09-01

    A gap distribution of trapped superthermal but nonrelativistic electrons may generate Langmuir waves with a high brightness temperature 1/2 mc-squared, which has been invoked to explain the solar type I radio continuum. The conditions under which the Langmuir waves can actually become this intense when the electrons are treated as magnetized with a gyrofrequency smaller than the plasma frequency are evaluated. For isotropic electrons at a single velocity, there arise many instabilities, but most disappear for a slightly broadened velocity distribution. A serious Cerenkov instability, equivalent to the two-stream instability, occurs for electrons of small pitch angles. It is avoided by a modest loss cone. Then the Langmuir waves within 45 deg of the magnetic field can indeed achieve the expected high brightness temperature. The solar type I radio continuum can be explained in terms of a nonrelativistic electron gap distribution. Superthermal microwave gyroradiation implies sufficient superthermal electrons that their Langmuir waves might cause observable microwave emission at twice the plasma frequency. 33 references.

  4. Dynamic array of dark optical traps

    NASA Astrophysics Data System (ADS)

    Daria, Vincent Ricardo; Rodrigo, Peter John; Glückstad, Jesper

    2004-01-01

    A dynamic array of dark optical traps is generated for simultaneous trapping and arbitrary manipulation of multiple low-index microstructures. The dynamic intensity patterns forming the dark optical trap arrays are generated using a nearly loss-less phase-to-intensity conversion of a phase-encoded coherent light source. Two-dimensional input phase distributions corresponding to the trapping patterns are encoded using a computer-programmable spatial light modulator, enabling each trap to be shaped and moved arbitrarily within the plane of observation. We demonstrate the generation of multiple dark optical traps for simultaneous manipulation of hollow "air-filled" glass microspheres suspended in an aqueous medium.

  5. Microfabricated linear Paul-Straubel ion trap

    DOEpatents

    Mangan, Michael A. (Albuquerque, NM); Blain, Matthew G. (Albuquerque, NM); Tigges, Chris P. (Albuquerque, NM); Linker, Kevin L. (Albuquerque, NM)

    2011-04-19

    An array of microfabricated linear Paul-Straubel ion traps can be used for mass spectrometric applications. Each ion trap comprises two parallel inner RF electrodes and two parallel outer DC control electrodes symmetric about a central trap axis and suspended over an opening in a substrate. Neighboring ion traps in the array can share a common outer DC control electrode. The ions confined transversely by an RF quadrupole electric field potential well on the ion trap axis. The array can trap a wide array of ions.

  6. Dysprosium magneto-optical traps

    E-print Network

    Seo Ho Youn; Mingwu Lu; Ushnish Ray; Benjamin L. Lev

    2010-07-08

    Magneto-optical traps (MOTs) of highly magnetic lanthanides open the door to explorations of novel phases of strongly correlated matter such as lattice supersolids and quantum liquid crystals. We recently reported the first MOTs of the five high abundance isotopes of the most magnetic atom, dysprosium. Described here are details of the experimental technique employed for repumper-free Dy MOTs containing up to half a billion atoms. Extensive characterization of the MOTs' properties---population, temperature, loading, metastable decay dynamics, trap dynamics---is provided.

  7. Dysprosium magneto-optical traps

    SciTech Connect

    Youn, Seo Ho; Lu Mingwu; Ray, Ushnish; Lev, Benjamin L. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3080 (United States)

    2010-10-15

    Magneto-optical traps (MOTs) of highly magnetic lanthanides open the door to explorations of novel phases of strongly correlated matter such as lattice supersolids and quantum liquid crystals. We recently reported the first MOTs of the five high-abundance isotopes of the most magnetic atom, dysprosium. Described here are details of the experimental technique employed for repumper-free Dy MOTs containing up to half a billion atoms. Extensive characterization of the MOTs' properties--population, temperature, loading, metastable decay dynamics, and trap dynamics--is provided.

  8. Dysprosium magneto-optical traps

    E-print Network

    Youn, Seo Ho; Ray, Ushnish; Lev, Benjamin L

    2010-01-01

    Magneto-optical traps (MOTs) of highly magnetic lanthanides open the door to explorations of novel phases of strongly correlated matter such as lattice supersolids and quantum liquid crystals. We recently reported the first MOTs of the five high abundance isotopes of the most magnetic atom, dysprosium. Described here are details of the experimental technique employed for repumper-free Dy MOTs containing up to half a billion atoms. Extensive characterization of the MOTs' properties---population, temperature, loading, metastable decay dynamics, trap dynamics---is provided.

  9. Traps for reflected Brownian motion

    Microsoft Academic Search

    Krzysztof Burdzy; Zhen-Qing Chen; Donald E. Marshall

    2006-01-01

    Consider an open set \\u000a\\u000a\\u0009, d ? 2, and a closed ball \\u000a\\u000a\\u0009. Let \\u000a\\u000a\\u0009 denote the expectation of the hitting time of B for reflected Brownian motion in D starting from x ? D. We say that D is a trap domain if \\u000a\\u000a\\u0009. A domain D is not a trap domain if and only if the reflecting Brownian motion

  10. The Elimination of Steam Traps 

    E-print Network

    Dickman, F.

    1985-01-01

    and potato diggers. 22 He applied for patent on the device and the patent was granted in 1911. Except -for a change to simplify the linkage in the 1930's, the design has remained essentially unchanged to this day. All other traps sold today have a... become World War II, various German sClentists studied and applied for patent protection on .simple orifice devices. Germany was in the midst o~ a de pression, and it was proven that simple orif~ce technology could be applied ~n steam trap~inQ240...

  11. Managing the Steam Trap Population 

    E-print Network

    Atlas, R. D.

    1983-01-01

    trap...well...out of sight, out of mind." "Our job is the operation of this plantat a profit. Steam trap maintenance? That's pretty far down the list." Such views on the part of upper management are certainly understandable, although a company... of pro grams that might explain how to close the g-ap on $670,000 and avoid the pitfalls most programs have. Close t he Gap ($670,000 to be 5aved) tOO~------------------,HO,OOO DEmEO HArORM~HCE lEUEl :..: VI ~ '0 ~ " ; 10 ~ i 8 ~ 70...

  12. Transfer of function across members of an equivalence class

    PubMed Central

    Catania, A. Charles; Horne, Pauline; Lowe, C. Fergus

    1989-01-01

    A child's presses on response windows behind which stimuli were presented via computer monitor occasionally lit lamps arranged in a column; a present was delivered when all lamps in the column were lit. During the operation of a multiple schedule, the child first learned low rates of pressing in the presence of STAR and high rates in the presence of TREE. Later, in an arbitrary matching task, the child learned to select STAR given wiggly WORM and TREE given BLOCK. When WORM and BLOCK were inserted into the multiple schedule, the low and high rates respectively correlated with STAR and TREE transferred to them. Tests of reflexivity (identity matching) and of symmetry of the arbitrary matching implied that STAR and WORM had become members of one equivalence class, and TREE and BLOCK had become members of another. ImagesFig. 1Fig. 4 PMID:22477590

  13. Homotropic Cooperativity from the Activation Pathway of the Allosteric Ligand-Responsive Regulatory Protein TRAP

    PubMed Central

    Kleckner, Ian R.; McElroy, Craig A.; Kuzmic, Petr; Gollnick, Paul; Foster, Mark P.

    2014-01-01

    The trp RNA-binding Attenuation Protein (TRAP) assembles into an 11-fold symmetric ring that regulates transcription and translation of trp-mRNA in bacilli via heterotropic allosteric activation by the amino acid tryptophan (Trp). Whereas nuclear magnetic resonance studies have revealed that Trp-induced activation coincides with both ?s-ms rigidification and local structural changes in TRAP, the pathway of binding of the 11 Trp ligands to the TRAP ring remains unclear. Moreover, because each of eleven bound Trp molecules is completely surrounded by protein, its release requires flexibility of Trp-bound (holo) TRAP. Here, we used stopped-flow fluorescence to study the kinetics of Trp binding by Bacillus stearothermophilus TRAP over a range of temperatures and we observed well-separated kinetic steps. These data were analyzed using non-linear least-squares fitting of several two- and three-step models. We found that a model with two binding steps best describes the data, although the structural equivalence of the binding sites in TRAP implies a fundamental change in the time-dependent structure of the TRAP rings upon Trp binding. Application of the two binding step model reveals that Trp binding is much slower than the diffusion limit, suggesting a gating mechanism that depends on the dynamics of apo TRAP. These data also reveal that Trp dissociation from the second binding mode is much slower than after the first Trp binding mode, revealing insight into the mechanism for positive homotropic allostery, or cooperativity. Temperature dependent analyses reveal that both binding modes imbue increases in bondedness and order toward a more compressed active state. These results provide insight into mechanisms of cooperative TRAP activation, and underscore the importance of protein dynamics for ligand binding, ligand release, protein activation, and allostery. PMID:24224873

  14. TRAPS AND TRAPPING TECHNIQUES FOR ADULT MOSQUITO CONTROL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research has been conducted during the past three years on the efficacy of propane powered traps to manage salt marsh mosquitoes on Atsena Otie, an isolated island in the Gulf of Mexico, located near Cedar Key, FL, USA. The target species has been Ochlerotatus taeniorhynchus. Twenty-one Mosquito Mag...

  15. General covariance, artificial gauge freedom and empirical equivalence

    NASA Astrophysics Data System (ADS)

    Pitts, James Brian

    This dissertation updates the debate over the nontriviality of general covariance for Einstein's General Theory of Relativity (GTR) and considers particle physics in the debate over underdetermination and empirical equivalence. Both tasks are tied to the unexplored issue of artificial gauge freedom, a valuable form of descriptive redundancy. Whereas Einstein took general covariance to characterize GTR, Kretschmann thought it merely a formal feature that any theory could have. Anderson and Friedman analyzed substantive general covariance as the lack of absolute objects, fields the same in all models. Some extant counterexamples and a new one involving the electron spinor field are resolved. However, Geroch and Giulini diagnose an absolute object in GTR itself in the metric's volume element. One might instead analyze substantive general covariance as formal general covariance achieved without hiding preferred coordinates as scalar "clock fields," recalling Einstein's early views. Theories with no metric or multiple metrics make the age of the universe meaningless or ambiguous, respectively, so the ancient and medieval debate over the eternity of the world should be recast. Particle physics provides case studies for empirical equivalence. Proca's electromagnetism with some nonzero photon mass constitutes a family of rivals to Maxwell's theory. Whereas any Proca theory can be distinguished empirically from Maxwell's, the Proca family approaches Maxwell's for small masses, yielding permanent underdetermination with only approximate empirical equivalence. The weak nuclear force also displays a smooth massless limit classically, but not after quantization, recalling the instability of empirical equivalence under change of auxiliary hypotheses. The standard electroweak theory apparently permits a photon mass term and hence underdetermination, but possible further unification might not. The question of underdetermination regarding massive gravity is unresolved. Physicists often reformulate a theory to install additional fields and new gauge symmetries preserving empirical content. Post-positivist philosophers might judge the result a distinct and inferior theory, but physicists consider it a perhaps superior formulation of the same theory. Evidently a step back from naive realism towards mathematical-empirical equivalence is appropriate for physical ontology and theory individuation. Artificial gauge freedom licenses a generalized Kretschmann objection, but the clock field case suggests a resolution.

  16. Collective coherent population trapping in a thermal field

    SciTech Connect

    Macovei, M.; Keitel, C. H. [Max-Planck Institute for Nuclear Physics, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Ficek, Z. [Max-Planck Institute for Nuclear Physics, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Department of Physics, School of Physical Sciences, University of Queensland, Brisbane, 4072 (Australia)

    2006-06-15

    We analyze the efficiency of coherent population trapping (CPT) in a superposition of the ground states of three-level atoms under the influence of the decoherence process induced by a broadband thermal field. We show that in a single atom there is no perfect CPT when the atomic transitions are affected by the thermal field. The perfect CPT may occur when only one of the two atomic transitions is affected by the thermal field. In the case when both atomic transitions are affected by the thermal field, we demonstrate that regardless of the intensity of the thermal field the destructive effect on the CPT can be circumvented by the collective behavior of the atoms. An analytic expression was obtained for the populations of the upper atomic levels which can be considered as a measure of the level of thermal decoherence. The results show that the collective interaction between the atoms can significantly enhance the population trapping in that the population of the upper state decreases with an increased number of atoms. The physical origin of this feature is explained by the semiclassical dressed-atom model of the system. We introduce the concept of multiatom collective coherent population trapping by demonstrating the existence of collective (entangled) states whose storage capacity is larger than that of the equivalent states of independent atoms.

  17. Collisional activation with random noise in ion trap mass spectrometry

    SciTech Connect

    McLuckey, S.A.; Goeringer, D.E.; Glish, G.L. [Oak Ridge National Lab., TN (United States)

    1992-07-01

    Random noise applied to the end caps of a quadrupole ion trap is shown to be an effective means for the collisional activation of trapped ions independent of mass/charge ratio and number of ions. This technique is compared and contrasted with conventional single-frequency collisional activation for the molecular ion of N,N-dimethylaniline, protonated cocaine, the molecular anion of 2,4,6-trinitrotoluene, and doubly protonated neuromedin U-8. Collisional activation with noise tends to produce more extensive fragmentation than the conventional approach due to the fact that product ions are also kinetically excited in the noise experiment. The efficiency of the noise experiment in producing detectable product ions relative to the conventional approach ranges from being equivalent to being a factor of 3 less efficient. Furthermore, discrimination against low mass/charge product ions is apparent in the data from multiply charged biomolecules. Nevertheless, collisional activation with random noise provides a very simple means for overcoming problems associated with the dependence of single-frequency collisional activation on mass/charge ratio and the number of ions in the ion trap. 45 refs., 7 figs.

  18. Task and work performance on Skylab missions 2, 3, and 4: Time and motion study: Experiment M151

    NASA Technical Reports Server (NTRS)

    Kubis, J. F.; Mclaughlin, E. J.; Jackson, J. M.; Rusnak, R.; Mcbride, G. H.; Saxon, S. V.

    1977-01-01

    Human task performance was evaluated under weightlessness conditions during long duration space flight in order to study the characteristics of the adaptation function. Results show that despite pronounced variability in training schedules and in initial reaction to the Skylab environment, in-flight task performance was relatively equivalent among Skylab crews, and behavioral performance continued to improve from beginning to end of all missions.

  19. Surface-electrode point Paul trap

    E-print Network

    Chuang, Isaac L.

    We present a model as well as experimental results for a surface electrode radiofrequency Paul trap that has a circular electrode geometry well suited for trapping single ions and two-dimensional planar ion crystals. The ...

  20. Capturing Energy Savings with Steam Traps 

    E-print Network

    Bockwinkel, R. G.; French, S. A.

    1997-01-01

    This paper will discuss the energy savings potential of steam traps and present the energy, economic, and environmental reason why an active steam trap maintenance program is good for the company's bottom line. Several case studies will be discussed...

  1. Energy Savings Through Steam Trap Management 

    E-print Network

    Gibbs, C.

    2008-01-01

    energy management controls. When the topic of energy management relates to steam trap management however, the focus becomes less clear and action less notable. The seemingly “low hanging” fruit of steam traps are not often tied to significant...

  2. Measuring acoustic fields in an optical trap

    E-print Network

    Sarabalis, Christopher J

    2014-01-01

    This thesis describes progress in the use of optical traps for measurement of acoustic fields, a first step toward acoustic micromanipulation in fluids. The optical trap used throughout this study is carefully characterized. ...

  3. Capturing Energy Savings with Steam Traps

    E-print Network

    Bockwinkel, R. G.; French, S. A.

    This paper will discuss the energy savings potential of steam traps and present the energy, economic, and environmental reason why an active steam trap maintenance program is good for the company's bottom line. Several case studies will be discussed...

  4. Inertial measurement via dynamics of trapped particles

    E-print Network

    Post, E. Rehmi, 1966-

    2003-01-01

    We describe theoretical and practical aspects of the particle trap as an inertial sensor. The insight motivating this approach is that a trapped particle acts like a mass on a spring, but the restoring forces are provided ...

  5. Fiber optic integration in planar ion traps

    E-print Network

    George, Elizabeth Marie

    2008-01-01

    Atomic ion traps are are excellent tools in atomic physics for studying single ions. Accurate measurement of the ion's electronic state in these ion traps is required by both atomic clocks and quantum computation. Quantum ...

  6. 36 CFR 1192.2 - Equivalent facilitation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...permitted where the alternative designs and technologies used will provide substantially equivalent or greater access to and usability of the vehicle. Departures are to be considered on a case-by-case basis by the Department of Transportation under the...

  7. Topological equivalences of differential graded algebras

    E-print Network

    Shipley, Brooke

    Topological equivalences of differential graded algebras. #12; "Rings up to homotopy" ring spectra ()gen. coh. theories with a product 1. For R a ring, H R is a ring spectrum. The cup product gives a graded product: p q

  8. Introducing Non-Unit Fractions and Equivalence

    NSDL National Science Digital Library

    WNET

    2008-08-22

    Students interpret fractions in which the denominator describes the number of equal parts and the numerator describes how many of those parts one has. They are also introduced to naming equivalent fractions by dividing a circle.

  9. 33 CFR 159.19 - Testing equivalency.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Certification Procedures § 159.19 Testing equivalency...manufacturer may apply to the Commanding Officer, USCG Marine Safety Center, 2100 2nd St. SW., Stop 7102,...

  10. Distinguishing Provenance Equivalence of Earth Science Data

    NASA Technical Reports Server (NTRS)

    Tilmes, Curt; Yesha, Ye; Halem, M.

    2010-01-01

    Reproducibility of scientific research relies on accurate and precise citation of data and the provenance of that data. Earth science data are often the result of applying complex data transformation and analysis workflows to vast quantities of data. Provenance information of data processing is used for a variety of purposes, including understanding the process and auditing as well as reproducibility. Certain provenance information is essential for producing scientifically equivalent data. Capturing and representing that provenance information and assigning identifiers suitable for precisely distinguishing data granules and datasets is needed for accurate comparisons. This paper discusses scientific equivalence and essential provenance for scientific reproducibility. We use the example of an operational earth science data processing system to illustrate the application of the technique of cascading digital signatures or hash chains to precisely identify sets of granules and as provenance equivalence identifiers to distinguish data made in an an equivalent manner.

  11. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120 Equivalents. (a) For ships...

  12. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120 Equivalents. (a) For ships...

  13. Energy Conservation Project Evaluation by Investment Equivalents 

    E-print Network

    Larson, R. J.

    1984-01-01

    Using discounted cash flow techniques, a new parameter for the quick economic evaluation of energy conservation ideas is calculated. The meaning of the calculated value, an 'Investment Equivalent of Energy Saving', is: 'The maximum amount...

  14. Neutrophil Extracellular Traps Kill Bacteria

    Microsoft Academic Search

    Volker Brinkmann; Ulrike Reichard; Christian Goosmann; Beatrix Fauler; Yvonne Uhlemann; David S. Weiss; Yvette Weinrauch; Arturo Zychlinsky

    2004-01-01

    Neutrophils engulf and kill bacteria when their antimicrobial granules fuse with the phagosome. Here, we describe that, upon activation, neutrophils release granule proteins and chromatin that together form extracellular fibers that bind Gram-positive and -negative bacteria. These neutrophil extracellular traps (NETs) degrade virulence factors and kill bacteria. NETs are abundant in vivo in experimental dysentery and spontaneous human appendicitis, two

  15. Prairie Dog Released from Trap

    USGS Multimedia Gallery

    A prairie dog returns to its burrow in Wind Cave National Park after scientists free it from a trap. The animal is part of a field test to determine the effectiveness of a USGS-developed oral sylvatic plague vaccine (SPV). This prairie dog was previously tagged, and its blood, hair, and whisker samp...

  16. Optical trapping in liquid crystals

    NASA Astrophysics Data System (ADS)

    Simoni, F.; Lucchetti, L.; Criante, L.; Bracalente, F.; Aieta, F.

    2010-08-01

    Optical trapping and manipulation of micrometric silica particles dispersed in a nematic liquid crystal is reported. Several kind of samples are considered: homeotropic and planar undoped cells and homeotropic and planar cells doped by a small amount of the azo-dye Methyl-Red. The incident light intensity is over the threshold for optical reorientation of the molecular director. The refractive index of the dispersed particles is lower than the ones of the liquid crystal therefore the usual conditions for laser trapping and manipulation are not fulfilled. Nevertheless optical trapping is possible and is closely related to the optical nonlinearity of the hosting liquid crystal1. Trapping in doped and undoped cells are compared and it is shown that in the first case intensity lower by more than one order of magnitude is required as compared to the one needed in undoped samples. The effect is faster and the structural forces are of longer range. The formation of bubble-gum like defects in doped samples under certain experimental conditions is also reported and discussed.

  17. Isoelectronic Traps in Gallium Phosphide

    NASA Astrophysics Data System (ADS)

    Christian, Theresa; Alberi, Kirstin; Beaton, Daniel; Fluegel, Brian; Mascarenhas, Angelo

    2015-03-01

    Isoelectronic substitutional dopants can result in strongly localized exciton traps within a host bandstructure such as gallium arsenide (GaAs) or gallium phosphide (GaP). These traps have received great attention for their role in the anomalous bandgap bowing of nitrogen or bismuth-doped GaAs, creating the dramatic bandgap tunability of these unusual dilute alloys. In the wider, indirect-bandgap host material GaP, these same isoelectronic dopants create bound states within the gap that can have very high radiative efficiency and a wealth of discrete spectral transitions illuminating the symmetry of the localized excitonic trap state. We will present a comparative study of nitrogen and bismuth isoelectronic traps in GaP. Research was supported by the U. S. Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division under contract DE-AC36-08GO28308 and by the Department of Energy Office of Science Graduate Fellowship Program (DOE SCGF), made possible in part by the American Recovery and Reinvestment Act of 2009, administered by ORISE-ORAU under contract no. DE-AC05-06OR23100.

  18. Trapped xenon in ordinary chondrites

    NASA Astrophysics Data System (ADS)

    Lavielle, Bernard; Marti, Kurt

    1992-12-01

    A trapped component of heavy noble gates representing a distinct solar system (presumably asteroid belt) reservoir is known to be concentrated in carbonaceous carriers of chondritic meteorites. The isotopic signature of trapped Xe in separates of the H4 chondrite Forest Vale (FV) was determined by combusting its carrier phases at 600 C in oxygen, discriminating against in situ produced nucleogenic components which are released above 600 C. The isotopic abundances of FV combustion-Xe (FVC-Xe) are compared to signatures of bulk trapped Xe in chondritic meteorites. We conclude that FVC-Xe represents the predominant trapped component in ordinary chondrites (OC) for which we adopt the term OC-Xe. Its isotopic signature differs from Xe in ureilites, in 'average carbonaceous chondrites', in earth's atmosphere, and in the solar wind. Additional minor Xe components were identified in type 3 chondrites and in the metal phase of chondrites. We discuss relationships among solar system Xe reservoirs and show that OC-Xe signature is consistent with a mixture of HL-Xe with slightly mass fractionated solar-type Xe.

  19. Towards the unification of inference structures in medical diagnostic tasks.

    PubMed

    Mira, J; Rives, J; Delgado, A E; Martínez, R

    1998-01-01

    The central purpose of artificial intelligence applied to medicine is to develop models for diagnosis and therapy planning at the knowledge level, in the Newell sense, and software environments to facilitate the reduction of these models to the symbol level. The usual methodology (KADS, Common-KADS, GAMES, HELIOS, Protégé, etc) has been to develop libraries of generic tasks and reusable problem-solving methods with explicit ontologies. The principal problem which clinicians have with these methodological developments concerns the diversity and complexity of new terms whose meaning is not sufficiently clear, precise, unambiguous and consensual for them to be accessible in the daily clinical environment. As a contribution to the solution of this problem, we develop in this article the conjecture that one inference structure is enough to describe the set of analysis tasks associated with medical diagnoses. To this end, we first propose a modification of the systematic diagnostic inference scheme to obtain an analysis generic task and then compare it with the monitoring and the heuristic classification task inference schemes using as comparison criteria the compatibility of domain roles (data structures), the similarity in the inferences, and the commonality in the set of assumptions which underlie the functionally equivalent models. The equivalences proposed are illustrated with several examples. Note that though our ongoing work aims to simplify the methodology and to increase the precision of the terms used, the proposal presented here should be viewed more in the nature of a conjecture. PMID:9550854

  20. Multilingual energy dictionary. [Equivalents in 6 languages

    SciTech Connect

    Isaacs, A. (ed.)

    1981-01-01

    This dictionary covers 1600 entries - ranging from oil well to synthetic natural gas and waste heat recovery - that cover both concepts and equipment, providing the equivalents of the most-important energy terms in six languages: English, French, German, Italian, Portuguese, and Spanish. Each term is listed six times - under each language, with all five foreign equivalents - permitting easy translation among all six languages. Separate entries are also given for British and American English where usage differs in the two countries.

  1. The Physical Mirror Equivalence for the Local

    NASA Astrophysics Data System (ADS)

    Cacciatori, Sergio Luigi; Compagnoni, Marco; Guerra, Stefano

    2015-01-01

    In this paper we consider the total space of the canonical bundle of and we use a proposal by Hosono, together with results of Seidel and Auroux-Katzarkov-Orlov, to deduce the physical mirror equivalence between and the derived Fukaya category of its mirror which assigns the expected central charge to BPS states. By construction, our equivalence is compatible with the mirror map relating the complex and the Kähler moduli spaces and with the computation of Gromov-Witten invariants.

  2. Dark matter and the equivalence principle

    NASA Technical Reports Server (NTRS)

    Frieman, Joshua A.; Gradwohl, Ben-Ami

    1993-01-01

    A survey is presented of the current understanding of dark matter invoked by astrophysical theory and cosmology. Einstein's equivalence principle asserts that local measurements cannot distinguish a system at rest in a gravitational field from one that is in uniform acceleration in empty space. Recent test-methods for the equivalence principle are presently discussed as bases for testing of dark matter scenarios involving the long-range forces between either baryonic or nonbaryonic dark matter and ordinary matter.

  3. Equivalent drawbead models for sheet forming simulation

    Microsoft Academic Search

    S. J. Moon; M. G. Lee; S. H. Lee; Y. T. Keum

    2010-01-01

    Equivalent drawbead models associated with drawbead types, with which the geometrical modeling of drawbeads can be replaced\\u000a in a numerical simulation of the stamping process, are introduced. The accuracy of the equivalent drawbead models rapidly\\u000a computing the drawbead restraining and opening forces, based on the hybrid membrane\\/bending method accommodating Barlat’s\\u000a anisotropic yield function for the plane stress state and the

  4. EQUIVALENCE CLASS FORMATION IN ELDERLY PERSONS

    Microsoft Academic Search

    Luis Antonio Pérez-González; Vanessa Moreno-Sierra

    conditional discriminations required for equivalence and testing of symmetry, transitivity, and equivalence. First, samples A1 or A2 were randomly presented with comparisons B1 and B2; selections of B1 in the presence of A1 and selections of B2 in the presence of A2 were reinforced. Then, B1 or B2 were the sample and C1 and C2 were the comparisons; se- lections

  5. Relationship between identity and equivalence conservation

    Microsoft Academic Search

    John E. Northman; Gerald E. Gruen

    1970-01-01

    Gave 60 2nd and 3rd graders 3 identity and 3 equivalence conservation tests to examine the hypothesis that identity conservation developmentally precedes equivalence conservation. Results indicate that conservation was exhibited in an all-or-none fashion with 3rd grade boys making more conservation responses than 3rd grade girls. No sex difference was found with 2nd graders. Thus results failed to support the

  6. The trap-loaded cylindrical antenna

    Microsoft Academic Search

    D. Smith; J. J. Green; Griffiss AFB

    1975-01-01

    The trap-loaded cylindrical antenna is a cylindrical antenna having one or more traps located in its arms. The traps are either parallel inductor-capacitor circuits or short-circuited transmission line stubs that are designed to be antiresonant (having essentially an infinite input impedance) at some particular frequency. The location and the antiresonant frequency of the traps are selected to enhance the radiation

  7. Equivalent Circuits as Related to Ionic Systems

    PubMed Central

    Finkelstein, Alan; Mauro, Alexander

    1963-01-01

    The purpose of this paper is to clarify the relationship between certain “equivalent circuits” and the fundamental flux equations of Nernst and Planck. It is shown that as a direct algebraic consequence of these equations one may construct two types of equivalent circuits for a homogeneous (charged or uncharged) membrane. The one, which we term the “pure electrical equivalent circuit,” correctly predicts all of the electrical properties of the membrane for both steady and transient states. The other, which we call the “mixed equivalent circuit,” predicts the steady state I, ? characteristics of the membrane and the steady state ionic fluxes; it is not applicable to non-steady state properties or measurements. We emphasize that with regard to the portrayal of the physical basis of the properties of a homogeneous membrane, the mixed equivalent circuit can be misleading. This is particularly significant because this same circuit can also be used to depict a mosaic membrane, in which case the circuit gives a realistic pictorialization of the physical origin of the membrane properties. It is hoped that our analysis will be of aid to workers in electrophysiology who make use of equivalent circuit terminology in discussing the behavior of the plasma membrane. PMID:19431324

  8. Electrocuting and electronic insect traps: Trapping efficiency and production of airborne particles

    Microsoft Academic Search

    Alberto B. Broce

    1993-01-01

    Five electrocuting insect traps were evaluated for their efficiency in eliminating house flies and moths from small premises, and for their production of insect fragments and airborne particles. An electronic trap which kills attracted insects by trapping them on a sticky surface was also included in the study. Airborne particles from the vicinity of traps in operation were collected on

  9. Modelling of Charge Trapping/De-trapping Induced Voltage Instability in High-k Gate Dielectrics

    E-print Network

    1 Modelling of Charge Trapping/De-trapping Induced Voltage Instability in High-k Gate Dielectrics nm SiO2/3 nm HfSiO dielectric stack. Index Terms--trapping and de-trapping induced voltage dielectrics (e.g. Hf-based) are shown to be potential candidates to replace SiO2 as gate dielectric [1

  10. AMU NEXRAD Exploitation Task

    NASA Technical Reports Server (NTRS)

    Lambert, Winifred C.; Wheeler, Mark M.

    1997-01-01

    This report documents the results of the Applied Meteorology Unit's NEXRAD Exploitation Task. The objectives of this task are to determine what radar signatures are present prior to and at the time of convection initiation, and to determine radar signatures which will help distinguish whether the ensuing convection will become severe. Radar data from the WSR-88D radar located at NWS Melbourne (WSR-88D/KMLB) were collected between June and September 1995, and 16 convective case studies were analyzed for which the radar was operating during the entire period of interest. All WSR-88D/KMLB products were scrutinized for their utility in detecting convection initiation and severe storm signatures. Through process of elimination, it was found that the 0.5 deg reflectivity product with the lowest reflectivity values displayed is the best product to monitor for convection initiation signatures. Seven meteorological features associated with the initiation of deep convection were identified: the Merritt Island and Indian River convergence zones, interlake convergence, horizontal convective rolls, the sea breeze, storm outflow boundaries, and fires. Their reflectivity values ranged from -5 to 20 dBZ. Of the three severe weather phenomena (winds greater than or equal to 50 kts, tornado, 3/4 inch hail), high wind events due to microbursts were most common in the data set. It was found that the values and trends of composite reflectivity, vertically integrated liquid, and core aspect ratio were key indicators of the potential of a cell to produce a microburst. The data were not analyzed for the other two severe weather phenomena because they rarely occurred during the data collection period. This report also includes suggestions for new WSR-88D products, summaries of ongoing research aimed at creating new products, and explicit recommended procedures for detecting convection initiation and severe storm signatures in the radar data using the currently available technology.

  11. Low energy muons in ion traps

    Microsoft Academic Search

    Xiang Fei

    2003-01-01

    Introducing low energy muons in ion traps could open the door for many interesting experiments that can provide sensitive tests for CPT and QED theory via precision spectroscopy. Negative muons can be slowed and cooled by cold, trapped antiproton plasma and electron plasma. Slow muons interact with trapped positrons can lead to the production of atomic antimuonium (mu^-e^+). Similarly, positive

  12. Search for Trapped Antihydrogen ALPHA Collaboration

    E-print Network

    Fajans, Joel

    Search for Trapped Antihydrogen ALPHA Collaboration G.B. Andresena , M.D. Ashkezarib , M. BaqueroDepartment of Physics, Swansea University, Swansea SA2 8PP, United Kingdom eInstituto de F´isica, Universidade Federal to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator

  13. Microchip-Based Trapped-Atom Clocks

    E-print Network

    Vladan Vuletic; Ian D. Leroux; Monika H. Schleier-Smith

    2011-04-20

    This is a chapter of a recently published book entitled Atom Chips, edited by Jakob Reichel and Vladan Vuletic. The contents of this chapter include: Basic Principles; Atomic-Fountain versus Trapped-Atom Clocks; Optical-Transition Clocks versus Microwave Clocks; Clocks with Magnetically Trapped Atoms--Fundamental Limits and Experimental Demonstrations; Readout in Trapped-Atom Clocks; and Spin Squeezing.

  14. Ability and task constraint determinants of complex task performance

    Microsoft Academic Search

    Phillip L. Ackerman; Anna T. Cianciolo

    2002-01-01

    Previous research on basic information-processing tasks has suggested that there may be a dissociation between the underlying process determinants of task performance and associations with ability measures. This study investigates this dissociation in the context of a complex skill-learning task—an air traffic control simulation called TRACON. A battery of spatial, numerical, and perceptual speed ability tests were administered, along with

  15. Ability and Task Constraint Determinants of Complex Task Performance

    Microsoft Academic Search

    Phillip L. Ackerman; Anna T. Cianciolo

    2002-01-01

    Previous research on basic information-processing tasks has suggested that there may be a dissociation between the underlying process determinants of task performance and associations with ability measures. This study investigates this dissociation in the context of a complex skill-learning task—an air traffic control simulation called TRACON. A battery of spatial, numerical, and perceptual speed ability tests were administered, along with

  16. EQUIVALENCE RELATIONS FOR TWO VARIABLE REAL ANALYTIC FUNCTION GERMS

    E-print Network

    that are not blow-analytically equivalent. The natural equivalence relations we first think of are the Cr coordinate analytic function germs. We say that f and g are Cr (right) equivalent if there is a local Cr equivalent, but not Cr+1 equivalent. In the family of germs Kt(x, y) = x4 + tx2 y2 + y4 , the phenomenon

  17. Characterizing traps causing random telegraph noise during trap-assisted tunneling gate-induced drain leakage

    NASA Astrophysics Data System (ADS)

    Yoo, Sung-Won; Shin, Joonha; Seo, Youngsoo; Kim, Hyunsuk; Jeon, Sangbin; Kim, Hyunsoo; Shin, Hyungcheol

    2015-07-01

    This paper presents an analysis of traps causing random telegraph noise (RTN) in trap-assisted tunneling (TAT) gate-induced drain leakage (GIDL) current. RTN was shown for the first time to occur as a result of electron trapping rather than hole trapping. In addition, the proper effective permittivity of two different materials is used to accurately determine the distance between two traps causing RTN in TAT GIDL in an oxide.

  18. Whatever Gave You That Idea? False Memories Following Equivalence Training: A Behavioral Account of the Misinformation Effect

    PubMed Central

    Challies, Danna M; Hunt, Maree; Garry, Maryanne; Harper, David N

    2011-01-01

    The misinformation effect is a term used in the cognitive psychological literature to describe both experimental and real-world instances in which misleading information is incorporated into an account of an historical event. In many real-world situations, it is not possible to identify a distinct source of misinformation, and it appears that the witness may have inferred a false memory by integrating information from a variety of sources. In a stimulus equivalence task, a small number of trained relations between some members of a class of arbitrary stimuli result in a large number of untrained, or emergent relations, between all members of the class. Misleading information was introduced into a simple memory task between a learning phase and a recognition test by means of a match-to-sample stimulus equivalence task that included both stimuli from the original learning task and novel stimuli. At the recognition test, participants given equivalence training were more likely to misidentify patterns than those who were not given such training. The misinformation effect was distinct from the effects of prior stimulus exposure, or partial stimulus control. In summary, stimulus equivalence processes may underlie some real-world manifestations of the misinformation effect. PMID:22084495

  19. Whatever gave you that idea? False memories following equivalence training: a behavioral account of the misinformation effect.

    PubMed

    Challies, Danna M; Hunt, Maree; Garry, Maryanne; Harper, David N

    2011-11-01

    The misinformation effect is a term used in the cognitive psychological literature to describe both experimental and real-world instances in which misleading information is incorporated into an account of an historical event. In many real-world situations, it is not possible to identify a distinct source of misinformation, and it appears that the witness may have inferred a false memory by integrating information from a variety of sources. In a stimulus equivalence task, a small number of trained relations between some members of a class of arbitrary stimuli result in a large number of untrained, or emergent relations, between all members of the class. Misleading information was introduced into a simple memory task between a learning phase and a recognition test by means of a match-to-sample stimulus equivalence task that included both stimuli from the original learning task and novel stimuli. At the recognition test, participants given equivalence training were more likely to misidentify patterns than those who were not given such training. The misinformation effect was distinct from the effects of prior stimulus exposure, or partial stimulus control. In summary, stimulus equivalence processes may underlie some real-world manifestations of the misinformation effect. PMID:22084495

  20. Conductance technique in MOSFETs: Study of interface trap properties in the depletion and weak inversion regimes

    NASA Astrophysics Data System (ADS)

    Haddara, Hisham S.; El-Sayed, Mohamed

    1988-08-01

    A new and accurate approach to a.c. conductance measurements on MOSFETs is presented. It is shown that the conductance technique can be used to study interface trap properties in most of the silicon band-gap by direct measurement on a single MOSFET. The equivalent circuit is analyzed and the influence of the channel length on the inversion layer response is discussed in detail. It is shown that the channel time constant is mainly determined by the channel length. For small channel lengths L < 5 traps can easily interact with the minority carrier band in inversion. Therefore, such traps can be studied in a similar way as those interacting with the majority carrier band in depletion.

  1. Theoretical analysis of a YBCO squirrel-cage type induction motor based on an equivalent circuit

    NASA Astrophysics Data System (ADS)

    Morita, G.; Nakamura, T.; Muta, I.

    2006-06-01

    A HTS induction motor, with a HTS squirrel-cage rotor, is analysed using an electrical equivalent circuit. The squirrel-cage winding in the rotor consists of rotor bars and end rings, and both are considered to be made of YBCO film conductors. A wide range of electric field versus current density in YBCO film is formulated based on the Weibull function, and analysed as a non-linear resistance in the equivalent circuit. It is shown that starting and accelerating torques of the HTS induction motor are improved drastically compared to those of a conventional induction motor. Furthermore, large synchronous torque can also be realized by trapping the magnetic flux in the rotor circuit because of the persistent current mode.

  2. Quantum beats in recombination of spin-correlated radical ion pairs with equivalent protons

    NASA Astrophysics Data System (ADS)

    Bagryansky, V. A.; Usov, O. M.; Borovkov, V. I.; Kobzeva, T. V.; Molin, Yu. N.

    2000-05-01

    Quantum beats caused by the hyperfine coupling (hfc) with magnetically equivalent protons were observed in the recombination fluorescence of the singlet-correlated pairs of secondary radical ions generated in cyclohexane solutions by ionizing radiation. In agreement with theoretical predictions, the ratio IH( t)/ I0( t) of fluorescence decay kinetics in high and zero magnetic fields showed narrow peaks for the radical cations with an even number of the equivalent protons. To generate radical pairs, p-terphenyl- d14 was used as an electron acceptor while the solvent holes were trapped by octamethyl-1,4-cyclohexadiene, tetramethylethylene, 9,10-octalin, cis-decalin, hexamethylbenzene, durene, p-diethylbenzene, p-xylene, or benzene. When diisopropylamine was used as a hole acceptor, a trough was observed instead of the strongest peak. The position of the strongest peak (trough) is determined by the value of hfc constant only and is independent of the number of protons.

  3. Steep magnetic trap for ultra cold atoms

    NASA Astrophysics Data System (ADS)

    Vuletic, V.; Hänsch, T. W.; Zimmermann, C.

    1996-11-01

    A combination of current coils and ferromagnetic pole shoes is used to construct a magnetic quadrupole trap for ultra cold neutral atoms. Field gradients of up to 3000 G/cm have been achieved continuously with an electric power consumption of only 10 watts. A maximum field gradient of 1 T/cm is calculated for a current that can be applied for several seconds. The trap has been loaded with 8 × 106 lithium atoms (7Li) from a magneto-optical trap and the energy distribution determined by stepwise reduction of the trapping potential. Finally, magnetic trapping of fermionic 6Li has been demonstrated.

  4. Trapping of charged particles by Bessel beams

    E-print Network

    Bialynicki-Birula, Iwo; Drozd, Nadbor

    2011-01-01

    There exist two well established methods to trap charged particles: the Penning trap and the Paul trap. The subject of this article is to present a third mechanism for trapping charged particles - trapping by beams of electromagnetic radiation. The essential role is played by the electric field configuration in the plane perpendicular to the beam axis (for nonrelativistic electrons, the magnetic field is less important). Particles are confined to the vicinity of the minimum-energy points. In particular, for beams of electromagnetic radiation carrying orbital angular momentum such points lie on the beam axis.

  5. Electrodynamic trap for neutral polar particles

    SciTech Connect

    Bluemel, R. [Department of Physics, Wesleyan University, Middletown, Connecticut 06459-0155 (United States)

    2011-04-15

    A superposition of inhomogeneous static and rapidly oscillating electric fields is capable of trapping neutral particles with a permanent electric dipole moment. Detailed numerical simulations prove the validity and stability of our trapping scheme. Thin rods of barium titanate (BaTiO{sub 3}) are presented as an example for trapping on the macroscale. HC{sub 17}N, a polar molecule of astrophysical significance, is presented as an example for trapping on the microscale. For HC{sub 17}N and the parameters chosen, the depth of the trap is 40 mK.

  6. Simple analytic potentials for linear ion traps

    NASA Technical Reports Server (NTRS)

    Janik, G. R.; Prestage, J. D.; Maleki, L.

    1989-01-01

    A simple analytical model was developed for the electric and ponderomotive (trapping) potentials in linear ion traps. This model was used to calculate the required voltage drive to a mercury trap, and the result compares well with experiments. The model gives a detailed picture of the geometric shape of the trapping potenital and allows an accurate calculation of the well depth. The simplicity of the model allowed an investigation of related, more exotic trap designs which may have advantages in light-collection efficiency.

  7. The reliability and stability of the turner and Engle working memory task

    Microsoft Academic Search

    Kitty Klein; William H. Fiss

    1999-01-01

    The present study explored the psychometric properties of Turner and Engle’s (1989) operation span task, a widely used measure\\u000a of working memory capacity. We administered the task three times to 33 college students, using equivalent test materials.\\u000a The interval between the first and second administrations was 3 weeks, with 6–7 weeks between the second and third administrations.\\u000a Alpha coefficients were

  8. Primary Task Performance as Affected by Secondary Task Involvement.

    ERIC Educational Resources Information Center

    Williamson, Troy W.; Cochran, Samuel W.

    This study proposed that performing a low-demand secondary task would improve a subject's control of attentional processes on a primary task of importance. Subjects were 60 public elementary school students 9, 10, or 11 years of age. Of these, 30 had been identified as learning disabled and 30 had been identified as non-learning-disabled. Each…

  9. Proceedings of a Symposium on Task Analyses/Task Inventories.

    ERIC Educational Resources Information Center

    Schroeder, Paul E., Ed.

    In November 1975, a group of 158 persons met in Columbus, Ohio, to discuss the processes and techniques of job task analysis and the use of task inventories. The papers presented at the symposium are reproduced in this document as prepared by their authors. For the two speakers who did not prepare papers, only references to papers previously…

  10. Origin of trapping in multicrystalline silicon

    NASA Astrophysics Data System (ADS)

    Gundel, Paul; Schubert, Martin C.; Warta, Wilhelm

    2008-10-01

    Defect sites in silicon, which temporarily capture excess charge carriers (traps), are a promising source of information on defect structures relevant for photovoltaic application of the material. In this work the correlation between traps in p-type silicon, structural crystal defects, and impurities is explored in order to find the origin of these traps in multicrystalline silicon. The trap density is compared to the density of different impurities and structural crystal defects. These comparisons reveal that the trap density is positively correlated with the oxygen density and negatively correlated with the density of the metallic impurities analyzed. In addition we show that structural crystal defects are necessary but not sufficient for the existence of high trap densities. In summary, structural crystal defects that are decorated by oxygen precipitates arise as likely origin of trap centers.

  11. Evaluation of trapping-web designs

    USGS Publications Warehouse

    Lukacs, P.M.; Anderson, D.R.; Burnham, K.P.

    2005-01-01

    The trapping web is a method for estimating the density and abundance of animal populations. A Monte Carlo simulation study is performed to explore performance of the trapping web for estimating animal density under a variety of web designs and animal behaviours. The trapping performs well when animals have home ranges, even if the home ranges are large relative to trap spacing. Webs should contain at least 90 traps. Trapping should continue for 5-7 occasions. Movement rates have little impact on density estimates when animals are confined to home ranges. Estimation is poor when animals do not have home ranges and movement rates are rapid. The trapping web is useful for estimating the density of animals that are hard to detect and occur at potentially low densities. ?? CSIRO 2005.

  12. Ion traps fabricated in a CMOS foundry

    NASA Astrophysics Data System (ADS)

    Mehta, K. K.; Eltony, A. M.; Bruzewicz, C. D.; Chuang, I. L.; Ram, R. J.; Sage, J. M.; Chiaverini, J.

    2014-07-01

    We demonstrate trapping in a surface-electrode ion trap fabricated in a 90-nm CMOS (complementary metal-oxide-semiconductor) foundry process utilizing the top metal layer of the process for the trap electrodes. The process includes doped active regions and metal interconnect layers, allowing for co-fabrication of standard CMOS circuitry as well as devices for optical control and measurement. With one of the interconnect layers defining a ground plane between the trap electrode layer and the p-type doped silicon substrate, ion loading is robust and trapping is stable. We measure a motional heating rate comparable to those seen in surface-electrode traps of similar size. This demonstration of scalable quantum computing hardware utilizing a commercial CMOS process opens the door to integration and co-fabrication of electronics and photonics for large-scale quantum processing in trapped-ion arrays.

  13. Ion traps fabricated in a CMOS foundry

    E-print Network

    K. K. Mehta; A. M. Eltony; C. D. Bruzewicz; I. L. Chuang; R. J. Ram; J. M. Sage; J. Chiaverini

    2014-06-13

    We demonstrate trapping in a surface-electrode ion trap fabricated in a 90-nm CMOS (complementary metal-oxide-semiconductor) foundry process utilizing the top metal layer of the process for the trap electrodes. The process includes doped active regions and metal interconnect layers, allowing for co-fabrication of standard CMOS circuitry as well as devices for optical control and measurement. With one of the interconnect layers defining a ground plane between the trap electrode layer and the p-type doped silicon substrate, ion loading is robust and trapping is stable. We measure a motional heating rate comparable to those seen in surface-electrode traps of similar size. This is the first demonstration of scalable quantum computing hardware, in any modality, utilizing a commercial CMOS process, and it opens the door to integration and co-fabrication of electronics and photonics for large-scale quantum processing in trapped-ion arrays.

  14. Ion traps fabricated in a CMOS foundry

    E-print Network

    Mehta, K K; Bruzewicz, C D; Chuang, I L; Ram, R J; Sage, J M; Chiaverini, J

    2014-01-01

    We demonstrate trapping in a surface-electrode ion trap fabricated in a 90-nm CMOS (complementary metal-oxide-semiconductor) foundry process utilizing the top metal layer of the process for the trap electrodes. The process includes doped active regions and metal interconnect layers, allowing for co-fabrication of standard CMOS circuitry as well as devices for optical control and measurement. With one of the interconnect layers defining a ground plane between the trap electrode layer and the p-type doped silicon substrate, ion loading is robust and trapping is stable. We measure a motional heating rate comparable to those seen in surface-electrode traps of similar size. This is the first demonstration of scalable quantum computing hardware, in any modality, utilizing a commercial CMOS process, and it opens the door to integration and co-fabrication of electronics and photonics for large-scale quantum processing in trapped-ion arrays.

  15. Trapping of radiation in plasmas

    SciTech Connect

    Riley, M.E.; Alford, W.J.

    1995-06-01

    The authors analyze the problem of radiation trapping (imprisonment) by the method of Holstein. The process is described by an integrodifferential equation which shows that the effective radiative decay rate of the system depends on the size and the shape of the active medium. Holstein obtains a global decay rate for a particular geometry by assuming that the radiating excited species evolves into a steady state spatial mode. The authors derive a new approximation for the trapped decay which has a space dependent decay rate and is easy to implement in a detailed computer simulation of a plasma confined within an arbitrary geometry. They analyze the line shapes that are relevant to a near-atmospheric-pressure mixture of He and Xe. This line-shape analysis can be utilized in either the Holstein formulae or the space-dependent decay approximation.

  16. Microscale ion trap mass spectrometer

    DOEpatents

    Ramsey, J. Michael (Knoxville, TN); Witten, William B. (Lancing, TN); Kornienko, Oleg (Lansdale, PA)

    2002-01-01

    An ion trap for mass spectrometric chemical analysis of ions is delineated. The ion trap includes a central electrode having an aperture; a pair of insulators, each having an aperture; a pair of end cap electrodes, each having an aperture; a first electronic signal source coupled to the central electrode; a second electronic signal source coupled to the end cap electrodes. The central electrode, insulators, and end cap electrodes are united in a sandwich construction where their respective apertures are coaxially aligned and symmetric about an axis to form a partially enclosed cavity having an effective radius r.sub.0 and an effective length 2z.sub.0, wherein r.sub.0 and/or z.sub.0 are less than 1.0 mm, and a ratio z.sub.0 /r.sub.0 is greater than 0.83.

  17. On the local equivalence of homogeneous CR-manifolds

    Microsoft Academic Search

    Wilhelm Kaup

    2005-01-01

    For certain classes of homogeneous Cauchy-Riemann manifolds it is shown that the local CR-equivalence problem is equivalent to the global CR-equivalence problem. Among these are large classes of compact linear group orbits.

  18. 30 CFR 71.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Approved sampling devices; equivalent concentrations. 71.206...Approved sampling devices; equivalent concentrations. The concentration...determined by dividing the weight of dust in milligrams collected...converting that concentration to an equivalent concentration as...

  19. 30 CFR 90.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Approved sampling devices; equivalent concentrations. 90.206...Approved sampling devices; equivalent concentrations. The concentration...determined by dividing the weight of dust in milligrams collected...converting that concentration to an equivalent concentration as...

  20. 30 CFR 71.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Approved sampling devices; equivalent concentrations. 71.206...Approved sampling devices; equivalent concentrations. The concentration...determined by dividing the weight of dust in milligrams collected...converting that concentration to an equivalent concentration as...

  1. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Whole equivalent of pitted dates. 987.105...Definitions § 987.105 Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be...

  2. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Whole equivalent of pitted dates. 987.105...Definitions § 987.105 Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be...

  3. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Whole equivalent of pitted dates. 987.105...Definitions § 987.105 Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be...

  4. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Whole equivalent of pitted dates. 987.105...Definitions § 987.105 Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be...

  5. 30 CFR 70.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Approved sampling devices; equivalent concentrations. 70.206...Approved sampling devices; equivalent concentrations. The concentration...determined by dividing the weight of dust in milligrams collected...converting that concentration to an equivalent concentration as...

  6. 30 CFR 70.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Approved sampling devices; equivalent concentrations. 70.206...Approved sampling devices; equivalent concentrations. The concentration...determined by dividing the weight of dust in milligrams collected...converting that concentration to an equivalent concentration as...

  7. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Whole equivalent of pitted dates. 987.105...Definitions § 987.105 Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be...

  8. 30 CFR 90.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Approved sampling devices; equivalent concentrations. 90.206...Approved sampling devices; equivalent concentrations. The concentration...determined by dividing the weight of dust in milligrams collected...converting that concentration to an equivalent concentration as...

  9. 30 CFR 90.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Approved sampling devices; equivalent concentrations. 90.206...Approved sampling devices; equivalent concentrations. The concentration...determined by dividing the weight of dust in milligrams collected...converting that concentration to an equivalent concentration as...

  10. 30 CFR 71.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Approved sampling devices; equivalent concentrations. 71.206...Approved sampling devices; equivalent concentrations. The concentration...determined by dividing the weight of dust in milligrams collected...converting that concentration to an equivalent concentration as...

  11. 30 CFR 70.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Approved sampling devices; equivalent concentrations. 70.206...Approved sampling devices; equivalent concentrations. The concentration...determined by dividing the weight of dust in milligrams collected...converting that concentration to an equivalent concentration as...

  12. Hypercube matrix computation task

    NASA Technical Reports Server (NTRS)

    Calalo, Ruel H.; Imbriale, William A.; Jacobi, Nathan; Liewer, Paulett C.; Lockhart, Thomas G.; Lyzenga, Gregory A.; Lyons, James R.; Manshadi, Farzin; Patterson, Jean E.

    1988-01-01

    A major objective of the Hypercube Matrix Computation effort at the Jet Propulsion Laboratory (JPL) is to investigate the applicability of a parallel computing architecture to the solution of large-scale electromagnetic scattering problems. Three scattering analysis codes are being implemented and assessed on a JPL/California Institute of Technology (Caltech) Mark 3 Hypercube. The codes, which utilize different underlying algorithms, give a means of evaluating the general applicability of this parallel architecture. The three analysis codes being implemented are a frequency domain method of moments code, a time domain finite difference code, and a frequency domain finite elements code. These analysis capabilities are being integrated into an electromagnetics interactive analysis workstation which can serve as a design tool for the construction of antennas and other radiating or scattering structures. The first two years of work on the Hypercube Matrix Computation effort is summarized. It includes both new developments and results as well as work previously reported in the Hypercube Matrix Computation Task: Final Report for 1986 to 1987 (JPL Publication 87-18).

  13. Reversibility of trapped hole annealing

    Microsoft Academic Search

    A. J. Lelis; H. E. Jr. Boesch; T. R. Oldham; F. B. McLean

    1988-01-01

    Annealing under negative bias of metal-oxide semiconductor field-effect transistors (MOSFETs) previously irradiated and annealed under positive bias is studied as a function of oxide field and time. Using three different sets of samples ranging from hard to soft, the authors have observed a considerable reversal of the oxide trapped charge component, ..delta..V\\/sub ot\\/, in the two harder sets and essentially

  14. Trapper readies trap for lizard

    NASA Technical Reports Server (NTRS)

    2000-01-01

    State-licensed animal trapper James Dean sets the open door of an animal trap on KSC. He hopes to catch a large monitor lizard spotted recently near S.R. 3, a route into the Center, by several area residents. The lizard is not a native of the area, and possibly a released pet. Dean is working with the cooperation of KSC and the Merritt Island National Wildlife Refuge.

  15. Enactment versus conceptual encoding: Equivalent item memory but different source memory

    PubMed Central

    Senkfor, Ava J.; Van Petten, Cyma; Kutas, Marta

    2008-01-01

    It has been suggested that performing a physical action (enactment) is an optimally effective encoding task, due to the incorporation of motoric information in the episodic memory trace, and later retrieval of that information. The current study contrasts old/new recognition of objects after enactment to a conceptual encoding task of cost estimation. Both encoding tasks yielded high accuracy, and robust differences in brain activity as compared to new objects, but no differences between encoding tasks. These results are not supportive of the idea that encoding by enactment leads to the spontaneous retrieval of motoric information. When participants were asked to discriminate between the two classes of studied objects during a source memory task, perform-encoded objects elicited higher accuracy and different brain activity than cost-encoded objects. The extent and nature of what was retrieved from memory thus depended on its utility for the assigned memory test: object information during the old/new recognition test, but additional information about the encoding task when necessary for a source memory test. Event-related potentials (ERPs) recorded during the two memory tests showed two orthogonal effects during an early (300-800 ms) time window: a differentiation between studied and unstudied objects, and a test-type (retrieval orientation) effect that was equivalent for old and new objects. Later brain activity (800-1300 ms) differentiated perform- from cost-encoded objects, but only during the source memory test, suggesting temporally distinct phases of retrieval. PMID:18472035

  16. On the equivalence of nonadiabatic fluids

    E-print Network

    W. Barreto

    2010-11-17

    Here we show how an anisotropic fluid in the diffusion limit can be equivalent to an isotropic fluid in the streaming out limit, in spherical symmetry. For a particular equation of state this equivalence is total, from one fluid we can obtain the other and vice versa. A numerical master model is presented, based on a generic equation of state, in which only quantitative differences are displayed between both nonadiabatic fluids. From a deeper view, other difference between fluids is shown as an asymmetry that can be overcome if we consider the appropriate initial-boundary conditions. Equivalence in this context can be considered as a first order method of approximation to study dissipative fluids.

  17. Equivalent magnetization over the World Ocean

    NASA Astrophysics Data System (ADS)

    Dyment, J.; Hamoudi, M.; Choi, Y.; Thebault, E.; Quesnel, Y.; Roest, W. R.; Lesur, V.

    2012-12-01

    In another presentation (Hamoudi et al., this meeting), we present the construction of a new candidate for the World Digital Magnetic Anomaly Map (WDMAM) over oceanic areas. This map is based on: (a) a more realistic forward modeling of the marine magnetic anomalies which includes remanent magnetization vectors taking into account the age and motion of the oceanic lithosphere; (b) evaluation of the equivalent magnetization by comparison of the synthetic and observed anomalies along ship tracks; and (c) adjustment of the synthetic anomaly maps using this equivalent magnetization prior to merging with the observed anomalies. A by-product of this approach is a global distribution of equivalent magnetization over the World's Ocean. Note that, because no global basement map exists for the oceanic areas, we assume a uniform, 5 km-deep and 1 km-thick magnetized layer for the forward model. The resulting equivalent magnetization is therefore relative to this over-simplistic magnetic source. A first observation is that, within the hypotheses of the forward model, the average equivalent magnetization is about 3 A/m, a value which compares well with the Natural Remanent Magnetization (NRM) measured on ancient basalt samples. As expected, the mid-ocean ridges are marked by stronger equivalent magnetizations, an observation which reflects both the stronger NRM measured at ridge axes and their shallower bathymetry (not taken into account in our forward model). More interesting is the observation of significant along-axis variations. In the North Atlantic Ocean, the Kolbeinsey and Reykjanes ridges around Iceland are marked by a very strong equivalent magnetization and the Azores Plateau by a strong one as well.. Again this may reflect the combined effect of shallower seafloor, thicker and/or more magnetized basaltic layer at hotspots. In contrast, the areas between 45 and 55°N and between 0 and 10°N (Equatorial FZ) correspond to a weak equivalent magnetization. Further south, the Mid-Atlantic Ridge displays a more uniform signature, although off-axis variations seem associated to the Tristan and St Helena hotspots. In the Indian Ocean, a strong equivalent magnetization characterizes areas of hotspot-ridge interaction such as the Gulf of Aden, the Central Indian Ridge near Rodrigues Island, the Southwest Indian Ridge near Marion Island, and the Southeast Indian Ridge near St Paul and Amsterdam Islands. A weaker one is observed in colder area, at the Australian-Antarctic Discordance and around the Rodrigues Triple Junction. The Pacific Ocean is characterized by a generally stronger equivalent magnetization, both near ridges and in abyssal plains. Time variations, i.e. along seafloor spreading flowlines, are apparent across the Mid-Atlantic and Pacific-Antarctic ridges, with highs near the ridge axis (younger than 10 Ma) and between ~83 and 60 Ma, just after the Cretaceous Normal Superchron and lows between ~60 and 10 Ma. The Mesozoic basins of the Pacific and Atlantic oceans show a weaker equivalent magnetization before ~155 Ma and a stronger one after. Basins covered by thick sediments such as the Bengal Bay, Great Australian Bight, Nova Scotia Basin, and Western Somali Basin show a very weak equivalent magnetization, reflecting both a deeper basement and a possible thermal demagnetization. Some of these variations coincide with satellite magnetic anomalies.

  18. Quantum formulation of the Einstein Equivalence Principle

    E-print Network

    Zych, Magdalena

    2015-01-01

    Validity of just a few physical conditions comprising the Einstein Equivalence Principle (EEP) suffices to ensure that gravity can be understood as space-time geometry. EEP is therefore subject to an ongoing experimental verification, with present day tests reaching the regime where quantum mechanics becomes relevant. Here we show that the classical formulation of the EEP does not apply in such a regime. The EEP requires equivalence between the total rest mass-energy of a system, the mass-energy that constitutes its inertia, and the mass-energy that constitutes its weight. In quantum mechanics internal energy is given by a Hamiltonian operator describing dynamics of internal degrees of freedom. We therefore introduce a quantum formulation of the EEP -- equivalence between the rest, inertial and gravitational internal energy operators. We show that the validity of the classical EEP does not imply the validity of its quantum formulation, which thus requires an independent experimental verification. We reanalyse...

  19. System Equivalent for Real Time Digital Simulator

    NASA Astrophysics Data System (ADS)

    Lin, Xi

    2011-07-01

    The purpose of this research is to develop a method of making system equivalents for the Real Time Digital Simulator (RTDS), which should enhance its capability of simulating large power systems. The proposed equivalent combines a Frequency Dependent Network Equivalent (FDNE) for the high frequency electromagnetic transients and a Transient Stability Analysis (TSA) type simulation block for the electromechanical transients. The frequency dependent characteristic for FDNE is obtained by curve-fitting frequency domain admittance characteristics using the Vector Fitting method. An approach for approximating the frequency dependent characteristic of large power networks from readily available typical power-flow data is also introduced. A new scheme of incorporating TSA solution in RTDS is proposed. This report shows how the TSA algorithm can be adapted to a real time platform. The validity of this method is confirmed with examples, including the study of a multi in-feed HVDC system based network.

  20. 30 CFR 71.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...false Approved sampling devices; equivalent concentrations. 71.206 Section 71.206 Mineral...206 Approved sampling devices; equivalent concentrations. The concentration of respirable dust shall be...

  1. 30 CFR 90.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...false Approved sampling devices; equivalent concentrations. 90.206 Section 90.206 Mineral...206 Approved sampling devices; equivalent concentrations. The concentration of respirable dust shall be...

  2. 30 CFR 70.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...false Approved sampling devices; equivalent concentrations. 70.206 Section 70.206 Mineral...206 Approved sampling devices; equivalent concentrations. The concentration of respirable dust shall be...

  3. 30 CFR 70.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...false Approved sampling devices; equivalent concentrations. 70.206 Section 70.206 Mineral...206 Approved sampling devices; equivalent concentrations. The concentration of respirable dust shall be...

  4. 30 CFR 71.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...false Approved sampling devices; equivalent concentrations. 71.206 Section 71.206 Mineral...206 Approved sampling devices; equivalent concentrations. The concentration of respirable dust shall be...

  5. 30 CFR 90.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...false Approved sampling devices; equivalent concentrations. 90.206 Section 90.206 Mineral...206 Approved sampling devices; equivalent concentrations. The concentration of respirable dust shall be...

  6. System Funding Task Force Report.

    ERIC Educational Resources Information Center

    Hale, Toussaint L., Jr.

    The System Funding Task Force (SFTF) of the Illinois Community College Board was formed to review the recommendations and framework for modifying the state's funding plan developed by the Board's President's Council. This report presents the SFTF's review of the Council's findings and presents the Task Force's own recommendations for funding.…

  7. Teachers' Aides: Tasks and Concerns

    ERIC Educational Resources Information Center

    Balderson, James H.; Nixon, Mary

    1976-01-01

    Addresses three questions: (1) What tasks do aides perform? (2) Does training make a difference in the type of tasks aides perform? (3) What are the concerns of aides? (Available from the Department of Educational Administration, The University of Alberta, Edmonton, Alberta, Canada T6G 2G5; $0.50, single copy.) (Author/IRT)

  8. Electricity Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This task list is intended for use in planning and/or evaluating a competency-based course in electricity. The guide outlines the tasks entailed in 10 different duties typically required of employees in the following occupations: residential electrician apprentice, material handler/supply clerk, maintenance electrician apprentice,…

  9. Ecosystem Task Force Meeting Minutes

    E-print Network

    New Hampshire, University of

    Ecosystem Task Force Meeting Minutes Date: April 28, 2011 Title of Meeting: Monthly Meeting. A focus on planning helps ground the Task Force because of the complexity of ecosystems. UNH-862-0785 sustainability.info@unh.edu http://www.sustainableunh.unh.edu/ #12;3.1. Ecosystem work has no defined parameters

  10. Welding Series. Duty Task List.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains the occupational duty/task lists for six occupations in the welding series. Each occupation is divided into a number of duties. A separate page for each duty in the occupation lists the tasks in that duty along with its code number and columns to indicate whether that particular duty has been taught and to provide space for…

  11. Traffic Safety Task Force Report

    E-print Network

    1 Traffic Safety Task Force Report September 2012 November Board of Trustees Meeting - Academic Paul Denton ­ OSUPD Traffic Safety Task Force Members 2 A special thanks goes to Jaime Pujol, College Hetrick, a master's in city and regional planning student, for his studies of pedestrian and cyclist

  12. Representations in Distributed Cognitive Tasks

    Microsoft Academic Search

    Jiajie Zhang; Donald A. Norman

    1994-01-01

    In this paper we propose a theoretical frame- work of distributed representations and a methodology of representational analysis for the study of distributed cognitive tasksÑtasks that require the processing of information distributed across the internal mind and the external envi- ronment. The basic principle of distributed rep- resentations is that the representational system of a distributed cognitive task is a

  13. TASK: Anarchy in the Artroom

    ERIC Educational Resources Information Center

    Schubert, Cynthia; Van Patten, Kelda

    2012-01-01

    Most teenagers do not really like to be told what to do. For that matter, most adults don't either. This article discusses contemporary artist Oliver Herring's TASK, which is an opportunity for participants to bend or define the rules on their own terms. It is about choice, and, for many, it is a dream come true. TASK is controlled chaos that can…

  14. Randomized Algorithms Metrical Task Systems

    E-print Network

    Irani, Sandy

    a randomized algorithm which is \\Gamma Hn +O( p log n) \\Delta ­competitive. 1 Introduction In computer systemsRandomized Algorithms for Metrical Task Systems Sandy Irani \\Lambda Steve Seiden y Department, Linial, and Saks introduce a general model for online systems in [BLS92] called task systems and show

  15. Cognitive task analysis for training

    Microsoft Academic Search

    Richard E. Clark; Fred Estes

    1996-01-01

    Two factors have made behaviorally based task analysis training systems obsolete: (1) these systems cannot describe the complex knowledge required of European and North American workers by recent changes in the global economy, and (2) recent research in cognition shows that the cognitive processes and structures involved in complex work tasks serve as a more useful content for training and

  16. 77 FR 55832 - Ambient Air Monitoring Reference and Equivalent Methods: Designation of a New Equivalent Method

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ...new equivalent method for measuring concentrations of PM 2.5 in the ambient air...various methods for monitoring the concentrations of those ambient air pollutants for...equivalent method for measuring pollutant concentrations of PM 2.5 in the ambient...

  17. Equivalent physical models and formulation of equivalent source layer in high-resolution EEG imaging.

    PubMed

    Yao, Dezhong; He, Bin

    2003-11-01

    In high-resolution EEG imaging, both equivalent dipole layer (EDL) and equivalent charge layer (ECL) assumed to be located just above the cortical surface have been proposed as high-resolution imaging modalities or as intermediate steps to estimate the epicortical potential. Presented here are the equivalent physical models of these two equivalent source layers (ESL) which show that the strength of EDL is proportional to the surface potential of the layer when the outside of the layer is filled with an insulator, and that the strength of ECL is the normal current of the layer when the outside is filled with a perfect conductor. Based on these equivalent physical models, closed solutions of ECL and EDL corresponding to a dipole enclosed by a spherical layer are given. These results provide the theoretical basis of ESL applications in high-resolution EEG mapping. PMID:14653557

  18. Electrokinetic trapping at the one nanometer limit

    PubMed Central

    Fields, Alexander P.; Cohen, Adam E.

    2011-01-01

    Anti-Brownian electrokinetic traps have been used to trap and study the free-solution dynamics of large protein complexes and long chains of DNA. Small molecules in solution have thus far proved too mobile to trap by any means. Here we explore the ultimate limits on trapping single molecules. We developed a feedback-based anti-Brownian electrokinetic trap in which classical thermal noise is compensated to the maximal extent allowed by quantum measurement noise. We trapped single fluorophores with a molecular weight of < 1 kDa and a hydrodynamic radius of 6.7 ? for longer than one second, in aqueous buffer at room temperature. This achievement represents an 800-fold decrease in the mass of objects trapped in solution, and opens the possibility to trap and manipulate any soluble molecule that can be fluorescently labeled. To illustrate the use of this trap, we studied the binding of unlabeled RecA to fluorescently labeled single-stranded DNA. Binding of RecA induced changes in the DNA diffusion coefficient, electrophoretic mobility, and brightness, all of which were measured simultaneously and on a molecule-by-molecule basis. This device greatly extends the size range of molecules that can be studied by room temperature feedback trapping, and opens the door to further studies of the binding of unmodified proteins to DNA in free solution. PMID:21562206

  19. 46 CFR 175.540 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...calculation, information, or test, which provides a level of...submitted to the Marine Safety Center via the cognizant OCMI. If necessary...require engineering evaluations and tests to demonstrate the equivalence...submitted to the Marine Safety Center via the cognizant OCMI....

  20. Early Verbal Developmental History and Equivalence Relations

    Microsoft Academic Search

    M. Carmen Luciano; Yvonne Barnes-Holmes; Dermot Barnes-Holmes

    2001-01-01

    Young children demonstrate the derivation of equivalence relations after only a brief training history. Although a number of theories have proposed possible variables that give rise to these effects, the role of the child's preverbal learning history has not been fully addressed. The present paper describes some perceptual skills that may be important for the later emergence of derived performances.

  1. 49 CFR 38.2 - Equivalent facilitation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...permitted where the alternative designs and technologies used will provide substantially equivalent or greater access to and usability of the vehicle. Departures are to be considered on a case-by-case basis under procedures set forth in § 37.7 of...

  2. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...an alternative to that required by both MARPOL 73/78 and subpart B of this part...and construction features prescribed by MARPOL 73/78 that are also prescribed by subpart...equivalent to a feature prescribed by MARPOL 73/78 that is authorized for a...

  3. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...an alternative to that required by both MARPOL 73/78 and subpart B of this part...and construction features prescribed by MARPOL 73/78 that are also prescribed by subpart...equivalent to a feature prescribed by MARPOL 73/78 that is authorized for a...

  4. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...an alternative to that required by both MARPOL 73/78 and subpart B of this part...and construction features prescribed by MARPOL 73/78 that are also prescribed by subpart...equivalent to a feature prescribed by MARPOL 73/78 that is authorized for a...

  5. Undecidable Equivalences for Basic Process Algebra

    E-print Network

    Hüttel, Hans

    BPA processes, which correspond to a class of context­free grammars generating the ffl­free context­free languages. In [21] Huynh and Tian have shown that readiness and failure equivalence are undecidable for BPA] and show that none of them are decidable for normed BPA processes. 1 Introduction In the field of process

  6. Research Article The Equivalence of Learning

    E-print Network

    Klahr, David

    reasoning associated with the evaluation of science- fair posters. We found not only that many more childrenResearch Article The Equivalence of Learning Paths in Early Science Instruction Effects of Direct children basic procedures for early scientific investigations. A widely accepted claim in the science

  7. TABLE OF SERVICE EQUIVALENT UNIFORMS ARMY MARINE

    E-print Network

    1 TABLE OF SERVICE EQUIVALENT UNIFORMS EVENT WHEN WORN ARMY MARINE CORPS NAVY AIR FORCE COAST GUARD White Jacket Mess Dress Dinner Dress White Jacket Tuxedo Evening Gown Army Blue (bow tie) Blue Dress "A Dress Less formal occasions requiring more formality than service uniforms Army White (bow tie) Blue

  8. AN UPDATE ON TECHNOLOGIES SEEKING PFRP EQUIVALENCY

    EPA Science Inventory

    This presentation will: 1) Review the mandate of the Pathogen Equivalency Committee (PEC), 2) Review the PEC's current membership (of 10), 3) Discuss how a typical application is evaluated, 4) Note where information can be found by those interested in applying to the PEC, 5) List...

  9. Antimatter gravity and the weak equivalence principle

    SciTech Connect

    Holzscheiter, M.H.; Brown, R.E.; Camp, J.; Darling, T.; Dyer, P.; Holtkamp, D.B.; Jarmie, N.; King, N.S.P.; Schauer, M.M. (Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)); Cornford, S.; Hosea, K.; Kenefick, R.A. (Texas A M University, College Station, Texas 77843 (United States)); Midzor, M.; Oakley, D.; Ristinen, R. (University of Colorado, Boulder, Colorado 80309 (United States)); Witteborn, F.C. (NASA Ames Research Center, Moffett Field, California 94305 (United States))

    1991-08-05

    Ideas are presented for an experiment to compare the acceleration, g, of antiprotons in the Earth's gravitational field with that of particles of normed matter, such as protons or hydrogen ions. The experiments will test whether antiprotons obey the weak equivalence principle.(AIP)

  10. Countable Borel Equivalence Relations I Simon Thomas

    E-print Network

    Thomas, Simon

    Countable Borel Equivalence Relations I Simon Thomas Rutgers University 5th November 2012 Simon) is a Borel set for each Borel set B Y. Simon Thomas (Rutgers University) Rutgers Logic Seminar 5th November the same topological space. Simon Thomas (Rutgers University) Rutgers Logic Seminar 5th November 2012 #12

  11. Countable Borel Equivalence Relations IV Simon Thomas

    E-print Network

    Andrews, Peter B.

    Countable Borel Equivalence Relations IV Simon Thomas Rutgers University 17th November 2007 Simon with a suitably chosen group of recursive permutations of N, we have that E T . Simon Thomas (Rutgers University. Simon Thomas (Rutgers University) Appalachian Set Theory Workshop 17th November 2007 #12;The ring of p

  12. Countable Borel Equivalence Relations IV Simon Thomas

    E-print Network

    Thomas, Simon

    Countable Borel Equivalence Relations IV Simon Thomas Rutgers University 3rd December 2012 Simon-theoretic account. Simon Thomas (Rutgers University) Rutgers Logic Seminar 3rd December 2012 #12;The plan Popa's criterion for untwisting cocycles Malleability of the action Local rigidity of cocycles Simon

  13. Countable Borel Equivalence Relations I Simon Thomas

    E-print Network

    Andrews, Peter B.

    Countable Borel Equivalence Relations I Simon Thomas Rutgers University 17th November 2007 Simon is Borel iff -1(B) is a Borel set for each Borel set B Y. Simon Thomas (Rutgers University) Appalachian), (R2, d2) induce the same topological space. Simon Thomas (Rutgers University) Appalachian Set Theory

  14. Classification and equivalence in estimation theory

    NASA Technical Reports Server (NTRS)

    Brockett, R. W.

    1979-01-01

    A method is proposed for classifying estimation problems based on the Lie algebra generated by the operators which appear in the conditional density equation. A natural class of automorphisms of this algebra is examined and a systematic method of generating equivalent problems is developed. Finally, a new class of nonlinear filtering problems with essentially nonlinear filtering equations are presented.

  15. An Algebraic Characterization of Equivalent Bayesian Networks

    E-print Network

    Regina, University of

    distribution, as its knowledge base; and an efficient inference engine [5], [4] for computing posterior with efficient inference engines [5], [4] for computing posterior probability based on observed evidence composes recently, Chicker- ing [1] reported a transformational characterization of equivalent Bayesian networks

  16. An Algebraic Characterization of Equivalent Bayesian Networks

    E-print Network

    Regina, University of

    distribution, as its knowledge base; and an e#cient inference engine [5], [4] for computing posterior with e#cient inference engines [5], [4] for computing posterior probability based on observed evidence or not [7]. More recently, Chicker­ ing [1] reported a transformational characterization of equivalent

  17. Equivalent weight of humic acid from peat

    USGS Publications Warehouse

    Pommer, A.M.; Breger, I.A.

    1960-01-01

    By means of discontinuous titration, the equivalent weight of humic acid isolated from a peat was found to increase from 144 to 183 between the third and fifty-second day after the humic acid was dissolved. Infra-red studies showed that the material had probably condensed with loss of carbonyl groups. ?? 1960.

  18. Acoustic Sounding of Snow Water Equivalent

    Microsoft Academic Search

    N. Kinar; J. W. Pomeroy

    2006-01-01

    The possibility of determining Snow Water Equivalent (SWE) by the use of an acoustic impulse was assessed for cold windswept snowcovers in Saskatchewan and temperate deep mountain snowcovers in British Columbia, Canada. The theory of sound propagation employed presumes that the snowpack is a two-phase, layered, porous medium. A horn and receiver located just above the snow surface sent and

  19. Equivalent weight of humic acid from peat

    Microsoft Academic Search

    A. M. Pommer; I. A. Breger

    1960-01-01

    By means of discontinuous titration, the equivalent weight of humic acid isolated from a peat was found to increase from 144 to 183 between the third and fifty-second day after the humic acid was dissolved. Infra-red studies showed that the material had probably condensed with loss of carbonyl groups.

  20. The Equivalence Principle and g-2 Experiments

    E-print Network

    C. Alvarez; R. B. Mann

    1995-10-31

    We consider the possibility of using measurements of anomalous magnetic moments of elementary particles as a possible test of the Einstein Equivalence Principle (EEP). For the class non-metric theories of gravity described by the \\tmu formalism we find several novel mechanisms for breaking the EEP, and discuss the possibilities of setting new empirical constraints on such effects.

  1. Equivalence Relations, Contextual Control, and Naming

    ERIC Educational Resources Information Center

    Randell, Tom; Remington, Bob

    2006-01-01

    This paper reports two experiments that investigated the role of verbal behavior in the emergence and generalization of contextually controlled equivalence classes. During both experiments, participants were trained with two different combinations of the same easily nameable, yet formally unrelated, pictorial stimuli. Match-to-sample baselines for…

  2. Biomonitoring Equivalents for DDT\\/DDE

    Microsoft Academic Search

    Christopher R. Kirman; Lesa L. Aylward; Sean M. Hays; Kannan Krishnan; Andy Nong

    2011-01-01

    Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of a chemical or its metabolite in a biological medium (blood, urine, or other medium) that is consistent with an existing health-based exposure guideline such as a reference dose (RfD) or tolerable daily intake (TDI). BE values can be used as a screening tool for the evaluation of

  3. Learning a Mahalanobis Metric from Equivalence Constraints

    Microsoft Academic Search

    Aharon Bar-Hillel; Tomer Hertz; Noam Shental; Daphna Weinshall

    2005-01-01

    Many learning algorithms use a metric defined over the input space as a principal tool, and their performance critically depends on the quality of this metric. We address the problem of learning metrics using side-information in the form of equivalence constraints. Unlike labels, we demonstrate that this type of side-information can sometimes be automatically obtained without the need of human

  4. Equivalence and Efficiency of Image Alignment Algorithms

    Microsoft Academic Search

    Simon Baker; Iain Matthews

    2001-01-01

    There are two major formulations of image alignment us- ing gradient descent. The first estimates an additive incre- ment to the parameters (the additive approach), the second an incremental warp (the compositionalapproach). We first prove that these two formulations are equivalent. A very ef- ficient algorithm was recently proposed by Hager and Bel- humeur using the additive approach that unfortunately

  5. Error equivalence theory for manufacturing process control

    Microsoft Academic Search

    Hui Wang

    2007-01-01

    Due to uncertainty in manufacturing processes, applied probability and statistics have been widely applied for quality and productivity improvement. In spite of significant achievements made in causality modeling for control of process variations, there exists a lack of understanding on error equivalence phenomenon, which concerns the mechanism that different error sources result in identical variation patterns on part features. This

  6. Using SAT for combinational equivalence checking

    Microsoft Academic Search

    Evguenii I. Goldberg; Mukul R. Prasad; Robert K. Brayton

    2001-01-01

    This paper addresses the problem of combinational equivalence checking (CEC) which forms one of the key componentsof the current verification methodology for dig- ital systems. A number of recently proposed BDD based approaches have met with considerable success in this area. However, the growing gap between the capability of current solvers and the complexity of verification instances neces- sitates the

  7. Electrophysiological Correlates of Stimulus Equivalence Processes

    ERIC Educational Resources Information Center

    Haimson, Barry; Wilkinson, Krista M.; Rosenquist, Celia; Ouimet, Carolyn; McIlvane, William J.

    2009-01-01

    Research reported here concerns neural processes relating to stimulus equivalence class formation. In Experiment 1, two types of word pairs were presented successively to normally capable adults. In one type, the words had related usage in English (e.g., uncle, aunt). In the other, the two words were not typically related in their usage (e.g.,…

  8. Private Speech on an Executive Task: Relations with Task Difficulty and Task Performance

    ERIC Educational Resources Information Center

    Fernyhough, C.; Fradley, E.

    2005-01-01

    Measures of private speech and task performance were obtained for a sample of 46 5- and 6-year-olds engaged on a mechanical version of the Tower of London (ToL) task. Two different sets of four puzzles of increasing difficulty were attempted on two occasions. In line with Vygotskian predictions, there was a quadratic relation between private…

  9. Resolving Task Rule Incongruence during Task Switching by Competitor Rule Suppression

    ERIC Educational Resources Information Center

    Meiran, Nachshon; Hsieh, Shulan; Dimov, Eduard

    2010-01-01

    Task switching requires maintaining readiness to execute any task of a given set of tasks. However, when tasks switch, the readiness to execute the now-irrelevant task generates interference, as seen in the task rule incongruence effect. Overcoming such interference requires fine-tuned inhibition that impairs task readiness only minimally. In an…

  10. Approaching the Trap-Free Limit in Organic Single-Crystal Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Blülle, Balthasar; Häusermann, Roger; Batlogg, Bertram

    2014-04-01

    We present measurements of rubrene single-crystal field-effect transistors with textbooklike transfer characteristics, as one would expect for intrinsically trap-free semiconductor devices. Particularly, the high purity of the crystals and the defect-free interface to the gate dielectric are reflected in an unprecedentedly low subthreshold swing of 65 mV/decade, remarkably close to the fundamental limit of 58.5 mV/decade. From these measurements, we quantify the residual density of traps by a detailed analysis of the subthreshold regime, including a full numerical simulation. An exceedingly low trap density of Dbulk=1×1013 cm-3 eV-1 at an energy of approximately 0.62 eV is found. This result corresponds to one trap per eV in 108 rubrene molecules. The equivalent density of traps located at the interface (Dit=3×109 cm-2 eV-1) is as low as in the best crystalline Si/Si field-effect transistors. These results highlight the benefit of having van der Waals bonded semiconducting crystals without electronically active states due to broken bonds at the surface.

  11. Orientation of Culex mosquitoes to carbon dioxide-baited traps: flight manoeuvres and trapping efficiency.

    PubMed

    Cooperband, M F; Cardé, R T

    2006-03-01

    Females of Culex quinquefasciatus Say and Culex tarsalis Coquillet (Diptera: Culicidae) in the host-seeking stage were released and video recorded in three dimensions in a large field wind tunnel as they flew to four kinds of CO2-baited mosquito traps. The trapping efficiency (number of mosquitoes approaching compared to the number caught) was determined for each trap type. The Encephalitis Virus Surveillance (EVS), Mosquito Magnet Freedom (MMF) and Mosquito Magnet Liberty (MML) traps captured only 13-16% of approaching Cx. quinquefasciatus females, whereas the Mosquito Magnet-X (MMX) trap captured 58%. Similar results were obtained for Cx. tarsalis. Orientation behaviour and flight parameters of mosquitoes approaching the four traps were compared. Mosquitoes spent the most time orienting to the EVS trap. Flight speed decreased as mosquitoes entered the vicinity of each trap and a large portion of their time was spent within 30 cm downwind of the traps. Flights became highly tortuous downwind of the poorly performing traps and just upwind of the MMX trap. Differences between traps and possible explanations for the superior performance of the MMX trap are considered. PMID:16608486

  12. Hydrogen-Trapping Mechanisms in Nanostructured Steels

    NASA Astrophysics Data System (ADS)

    Szost, B. A.; Vegter, R. H.; Rivera-Díaz-del-Castillo, Pedro E. J.

    2013-10-01

    Nanoprecipitation-hardened martensitic bearing steels (100Cr6) and carbide-free nanobainitic steels (superbainite) are examined. The nature of the hydrogen traps present in both is determined via the melt extraction and thermal desorption analysis techniques. It is demonstrated that 100Cr6 can admit large amounts of hydrogen, which is loosely bound to dislocations around room temperature; however, with the precipitation of fine coherent vanadium carbide traps, hydrogen can be immobilized. In the case of carbide-free nanostructured bainite, retained austenite/bainite interfaces act as hydrogen traps, while concomitantly retained austenite limits hydrogen absorption. In nanostructured steels where active hydrogen traps are present, it is shown that the total hydrogen absorbed is proportional to the trapped hydrogen, indicating that melt extraction may be employed to quantify trapping capacity.

  13. Trapping Rydberg Atoms in an Optical Lattice

    SciTech Connect

    Anderson, S. E.; Younge, K. C.; Raithel, G. [FOCUS Center, Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2011-12-23

    Rubidium Rydberg atoms are laser excited and subsequently trapped in a one-dimensional optical lattice (wavelength 1064 nm). Efficient trapping is achieved by a lattice inversion immediately after laser excitation using an electro-optic technique. The trapping efficiency is probed via analysis of the trap-induced shift of the two-photon microwave transition 50S{yields}51S. The inversion technique allows us to reach a trapping efficiency of 90%. The dependence of the efficiency on the timing of the lattice inversion and on the trap laser power is studied. The dwell time of 50D{sub 5/2} Rydberg atoms in the lattice is analyzed using lattice-induced photoionization.

  14. Tube length-assisted optimized aerosol trapping

    NASA Astrophysics Data System (ADS)

    Taheri, S. Mohammad-Reza; Sadeghi, Mohammad; Madadi, Ebrahim; S. Reihani, S. Nader

    2014-10-01

    Trapping a single aerosol using optical tweezers could be of great importance for environmental sciences. Though a single nanoparticle as small as 10 nm is successfully trapped in aqueous media using optical tweezers, due to spherical aberration only large clusters of nanoparticles were stably trapped in air. In this paper we provide our theoretical and experimental results on optimized trapping of aerosols as small as 400 nm in radius by the introduction of an extra spherical aberration source in order to minimize the total spherical aberration of the system. Our method allows for trapping of high refractive index particles such as polystyrene beads in air. It also provides considerably large trappable depth range which endows in-depth trapping. Our theoretical and experimental results are in very good agreement.

  15. Dielectrophoretic Traps for Single-Particle Patterning

    PubMed Central

    Rosenthal, Adam; Voldman, Joel

    2005-01-01

    We present a novel microfabricated dielectrophoretic trap designed to pattern large arrays of single cells. Because flowing away untrapped cells is often the rate-limiting step during cell patterning, we designed the trap to be strong enough to hold particles against practical flow rates. We experimentally validated the trap strength by measuring the maximum flow rate that polystyrene beads could withstand while remaining trapped. These bead experiments have shown excellent agreement with our model predictions, without the use of fitting parameters. The model was able to provide us with a fundamental understanding of how the traps work, and additionally allowed us to establish a set of design rules for optimizing the traps for a wide range of cell sizes. We provide the foundations for an enabling technology that can be used to pattern cells in unique ways, allowing us to do novel cell biology experiments at the microscale. PMID:15613624

  16. Portable Pbars, traps that travel

    SciTech Connect

    Howe, S.D.; Hynes, M.V.; Picklesimer, A.

    1987-10-01

    The advent of antiproton research utilizing relatively small scale storage devices for very large numbers of these particles opens the possibility of transporting these devices to a research site removed from the accelerator center that produced the antiprotons. Such a portable source of antiprotons could open many new areas of research and make antiprotons available to a new research community. At present antiprotons are available at energies down to 1 MeV. From a portable source these particles can be made available at energies ranging from several tens of kilovolts down to a few millielectron volts. These low energies are in the domain of interest to the atomic and condensed matter physicist. In addition such a source can be used as an injector for an accelerator which could increase the energy domain even further. Moreover, the availability of such a source at a university will open research with antiprotons to a broader range of students than possible at a centralized research facility. This report focuses on the use of ion traps, in particular cylindrical traps, for the antiproton storage device. These devices store the charged antiprotons in a combination of electric and magnet fields. At high enough density and low enough temperature the charged cloud will be susceptible to plasma instabilities. Present day ion trap work is just starting to explore this domain. Our assessment of feasibility is based on what could be done with present day technology and what future technology could achieve. We conclude our report with a radiation safety study that shows that about 10/sup 11/ antiprotons can be transported safely, however the federal guidelines for this transport must be reviewed in detail. More antiprotons than this will require special transportation arrangements. 28 refs., 8 figs.

  17. How Cross-Language Similarity and Task Demands Affect Cognate Recognition

    ERIC Educational Resources Information Center

    Dijkstra, Ton; Miwa, Koji; Brummelhuis, Bianca; Sappelli, Maya; Baayen, Harald

    2010-01-01

    This study examines how the cross-linguistic similarity of translation equivalents affects bilingual word recognition. Performing one of three tasks, Dutch-English bilinguals processed cognates with varying degrees of form overlap between their English and Dutch counterparts (e.g., "lamp-lamp" vs. "flood-vloed" vs. "song-lied"). In lexical…

  18. A Study of the Concurrent Validity of a Group Reasoning Test Built from Piaget's Tasks.

    ERIC Educational Resources Information Center

    Stefanich, Greg; And Others

    Researchers have attempted to develop paper and pencil Piagetian tests that yield results equivalent to manipulative Piagetian tasks and that can be administered in significantly less time. This study is an attempt to partially replicate and extend the findings of research by Paul Ankeny and Lyle Joyce who found significant positive correlations…

  19. Radiation Belts and Trapped Particles

    NSDL National Science Digital Library

    This tutorial introduces students to Earth's radiation belts, also known as the Van Allen Belts after their discoverer. Topics include the structure of the radiation belts and the currents of particles trapped in Earth's magnetic fields, their properties, and where they come from. There is also a set of classroom activities for exploring radiation belts and solar storms and a set of illustrations and movies of the belts. Other materials include news items related to the radiation belts, recordings of 'space sounds' related to the influence of lightning on Earth's magnetic field, and a frequently-asked-questions feature.

  20. Trapped iron measured on LDEF

    SciTech Connect

    Beaujean, R.; Jonathal, D.; Barz, S.; Enge, W.

    1995-02-01

    Heavy ions far below the cutoff energy were detected on the 28.5 deg inclination orbit of LDEF in a plastic track detector experiment. The Fe-group particles show a constant energy spectrum at 50 less than or equal to E less than or equal to 200 MeV/nuc. The steep energy spectrum of Fe-particles at 20 less than or equal to E less than or equal to 50 MeV/nuc and the arrival directions of these ions is consistent with a trapped component incident in the South Atlantic Anomaly at values of L=1.4-1.6.

  1. Trapped iron measured on LDEF

    NASA Technical Reports Server (NTRS)

    Beaujean, R.; Jonathal, D.; Barz, S.; Enge, W.

    1995-01-01

    Heavy ions far below the cutoff energy were detected on the 28.5 deg inclination orbit of LDEF in a plastic track detector experiment. The Fe-group particles show a constant energy spectrum at 50 less than or equal to E less than or equal to 200 MeV/nuc. The steep energy spectrum of Fe-particles at 20 less than or equal to E less than or equal to 50 MeV/nuc and the arrival directions of these ions is consistent with a trapped component incident in the South Atlantic Anomaly at values of L=1.4-1.6.

  2. Diffusion to finite-size traps

    SciTech Connect

    Richards, P.M.

    1986-04-28

    The survival probability of a random-walking particle is derived for hopping in a random distribution of traps of arbitrary radius and concentration. The single-center approximation is shown to be valid for times of physical interest even when the fraction of volume occupied by traps approaches unity. The theory is based on computation of the number of different potential trap regions sampled in a random walk and is confirmed by simulations on a simple-cubic lattice.

  3. State-insensitive bichromatic optical trapping

    SciTech Connect

    Arora, Bindiya; Safronova, M. S.; Clark, Charles W. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, Maryland 20899-8410 (United States)

    2010-08-15

    We study a scheme for state-insensitive trapping of neutral atoms by using light with two independent wavelengths. In particular, we describe the use of trapping and control lasers to minimize the variance of the potential experienced by a trapped Rb atom in ground and excited states. We present calculated values of wavelength pairs for which the 5s and 5p{sub 3/2} levels have the same ac Stark shifts in the presence of two laser fields.

  4. Outer trapped surfaces are dense near MOTSs

    NASA Astrophysics Data System (ADS)

    Chru?ciel, Piotr T.; Galloway, Gregory J.

    2014-02-01

    We show that any vacuum initial data set containing a marginally outer trapped surface S and satisfying a ‘no KIDs’ condition can be perturbed near S so that S becomes strictly outer trapped in the new vacuum initial data set. This, together with the results in Eichmair et al (2012), gives a precise sense in which generic initial data containing marginally outer trapped surfaces lead to geodesically incomplete spacetimes.

  5. Conjugacy and equivalence of weighted automata and functional transducers

    E-print Network

    Paris-Sud XI, Université de

    Conjugacy and equivalence of weighted automata and functional transducers Marie-Pierre B´eal1 equivalent K-automata are conjugate to a third one, when K is equal to B, N, Z, or any (skew) field In a recent paper ([1]), we have studied the equivalence of Z-automata. This equivalence is known

  6. The transfer of avoidance evoking functions through stimulus equivalence classes

    Microsoft Academic Search

    Erik M. Augustson; Michael J. Dougher

    1997-01-01

    Recent research in the area of stimulus equivalence suggests that transfer of function via members of stimulus equivalence classes may have relevance to human emotional responding and the development and generalization of certain psychological disorders. This study investigated the transfer of avoidance evoking functions through equivalence classes. Eight subjects were trained in the necessary relations for two-four member stimulus equivalence

  7. Atomic Clock Based On Linear Ion Trap

    NASA Technical Reports Server (NTRS)

    Prestage, John D.; Dick, G. John

    1992-01-01

    Highly stable atomic clock based on excitation and measurement of hyperfine transition in 199Hg+ ions confined in linear quadrupole trap by radio-frequency and static electric fields. Configuration increases stability of clock by enabling use of enough ions to obtain adequate signal while reducing non-thermal component of motion of ions in trapping field, reducing second-order Doppler shift of hyperfine transition. Features described in NPO-17758 "Linear Ion Trap for Atomic Clock." Frequency standard based on hyperfine transition described in NPO-17456, "Trapped-Mercury-Ion Frequency Standard."

  8. Detection of surface and bulk traps

    NASA Astrophysics Data System (ADS)

    von Seggern, Heinz

    1981-06-01

    A method for determining the geometrical surface trap structure of highly insulating polymer films is presented. We compare ''open-circuit'' thermally-stimulated current measurements of corona and electron-beam-charged foils. We present the results for three different polymers: polyfluoroethylenepropylene [Teflon (FEP)], polyethyleneterephthalate [Mylar (PET)], and Polyethylene (PE). For Teflon one observes that the surface traps are energetically shallower than the bulk traps, for Mylar no separate surface traps exist whereas for polyethylene the situation is opposite to Teflon. The spatial resolution of the method is 0.5 ?m.

  9. Voluntary Task Switching: Chasing the Elusive Homunculus

    ERIC Educational Resources Information Center

    Arrington, Catherine M.; Logan, Gordon D.

    2005-01-01

    In the voluntary task switching procedure, subjects choose the task to perform on a series of bivalent stimuli, requiring top-down control of task switching. Experiments 1-3 contrasted voluntary task switching and explicit task cuing. Choice behavior showed small, inconsistent effects of external stimulus characteristics, supporting the assumption…

  10. Task Assignment on Uniform Heterogeneous Multiprocessors

    Microsoft Academic Search

    Shelby Funk; Sanjoy K. Baruah

    2005-01-01

    The partitioning of periodic task systems upon uniform multiprocessors is considered. In the partitioned approach to scheduling periodic tasks upon multiprocessors, each task is assigned to a specific processor and all jobs gen- erated by a task are required to execute upon the processor to which the task is assigned. A uniform heterogeneous mul- tiprocessor is a multiprocessor in which

  11. Task Analysis and the Design of Functionality

    Microsoft Academic Search

    David E. Kieras

    1997-01-01

    Task analysis is the process of understanding the user's task thoroughly enough to help design a computer system that will effectively support users in doing the task. By task is meant the user's job or work activities, what the user is attempting to accomplish. By analysis is meant a relatively systematic approach to understanding the user's task that goes beyond

  12. Representing Identity and Equivalence for Scientific Data

    NASA Astrophysics Data System (ADS)

    Wickett, K. M.; Sacchi, S.; Dubin, D.; Renear, A. H.

    2012-12-01

    Matters of equivalence and identity are central to the stewardship of scientific data. In order to properly prepare for and manage the curation, preservation and sharing of digitally-encoded data, data stewards must be able to characterize and assess the relationships holding between data-carrying digital resources. However, identity-related questions about resources and their information content may not be straightforward to answer: for example, what exactly does it mean to say that two files contain the same data, but in different formats? Information content is frequently distinguished from particular representations, but there is no adequately developed shared understanding of what this really means and how the relationship between content and its representations hold. The Data Concepts group at the Center for Informatics Research in Science and Scholarship (CIRSS), University of Illinois at Urbana Champaign, is developing a logic-based framework of fundamental concepts related to scientific data to support curation and integration. One project goal is to develop precise accounts of information resources carrying the same data. We present two complementary conceptual models for information representation: the Basic Representation Model (BRM) and the Systematic Assertion Model (SAM). We show how these models provide an analytical account of digitally-encoded scientific data and a precise understanding of identity and equivalence. The Basic Representation Model identifies the core entities and relationships involved in representing information carried by digital objects. In BRM, digital objects are symbol structures that express propositional content, and stand in layered encoding relationships. For example, an RDF description may be serialized as either XML or N3, and those expressions in turn may be encoded as either UTF-8 or UTF-16 sequences. Defining this encoding stack reveals distinctions necessary for a precise account of identity and equivalence relationships. The Systematic Assertion Model focuses on key provenance events through which propositional content and symbol structures acquire the status of data content and data, respectively. Attention is on events such as a selection of symbols to express propositional content, or an appeal to observational evidence to advance a claim. SAM explicitly identifies data as the primary form of expression the one directly expressing content for a systematic assertion, an assertion where claims are warranted by an observation or a computation event. Under these models, equivalence relationships may hold between different data expressing the same content, or between different encodings of the same data. Equivalence relationships also hold among different data supporting the same claim and when contrasting claims are based on the same observations. SAM and BRM support a fine-grained characterization of scientific equivalence relationships that can be documented through ordinary data stewardship practices.

  13. Comparative efficiency of six stable fly (Diptera: Muscidae) traps.

    PubMed

    Taylor, David B; Berkebile, Dennis

    2006-08-01

    Five adhesive traps and the Nzi cloth-target trap were compared to determine their trapping efficiency and biases for stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae). Two configurations of the BiteFree prototype trap, constructed of polyethylene terephthalate, were most efficient for trapping stable flies, whereas the EZ trap was least efficient. The two Alsynite traps, Broce and Olson, were intermediate to the BiteFree prototype and EZ traps. All adhesive traps collected a ratio of approximately two males for each female. Approximately 50% of the flies collected on the adhesive traps, both male and female, were blood fed, and 20% were vitellogenic. The Nzi trap collected an older component of the stable fly population, 81% blood fed and 62% vitellogenic, but it was much less efficient than the adhesive traps. The effectiveness of the BiteFree prototype trap indicates that materials other than Alsynite are attractive to stable flies. PMID:16937700

  14. Trapping of Saker Falcon Falco cherrug and Peregrine Falcon Falco peregrinus in Saudi Arabia: Implications for biodiversity conservation

    PubMed Central

    Shobrak, Mohammed Y.

    2014-01-01

    The numbers of Falco cherrug and Falco peregrinus trapped during their migration over the Kingdom of Saudi Arabia (KSA) were investigated from published reports and through interviews with well-known trappers and dealers over several years (1989–2013). The number of trapped individuals increased for both species over a 23 year period, which is probably related to an enhanced trapping effort. Time series analysis suggests that the number of Saker Falcons being trapped is likely to be stable with annual fluctuations in the coming ten-year period, whereas the number of trapped Peregrine Falcons will probably decline with a small fluctuation initially. Using the population viability analysis suggests a high extinction rate for the Saker Falcon population migrating through KSA during the coming 10 and 20 years; whereas Peregrine Falcons probably take more than 100 years to reach the extinction threshold. However, the increase in the trapping period, especially in the spring, that has been observed during the last five years could increase the number of falcons trapped in the future. As both falcon species are migratory, implementing conservation actions across all range states is important to ensure a favourable conservation status for the Saker and Peregrine Falcons. Both species will benefit through the implementation of the Global Action Plan (GAP), developed by the Saker Falcon Task Force.

  15. Trapping of Saker Falcon Falco cherrug and Peregrine Falcon Falco peregrinus in Saudi Arabia: Implications for biodiversity conservation.

    PubMed

    Shobrak, Mohammed Y

    2015-07-01

    The numbers of Falco cherrug and Falco peregrinus trapped during their migration over the Kingdom of Saudi Arabia (KSA) were investigated from published reports and through interviews with well-known trappers and dealers over several years (1989-2013). The number of trapped individuals increased for both species over a 23 year period, which is probably related to an enhanced trapping effort. Time series analysis suggests that the number of Saker Falcons being trapped is likely to be stable with annual fluctuations in the coming ten-year period, whereas the number of trapped Peregrine Falcons will probably decline with a small fluctuation initially. Using the population viability analysis suggests a high extinction rate for the Saker Falcon population migrating through KSA during the coming 10 and 20 years; whereas Peregrine Falcons probably take more than 100 years to reach the extinction threshold. However, the increase in the trapping period, especially in the spring, that has been observed during the last five years could increase the number of falcons trapped in the future. As both falcon species are migratory, implementing conservation actions across all range states is important to ensure a favourable conservation status for the Saker and Peregrine Falcons. Both species will benefit through the implementation of the Global Action Plan (GAP), developed by the Saker Falcon Task Force. PMID:26150757

  16. Security tasks are highly interdependent.

    E-print Network

    Motivation Security tasks are highly interdependent. To improve security tools, we need Department of Electrical and Computer Engineering University of British Columbia Results Diverse, Customized Security practitioners perform many activities: · Information exchanged in different formats across

  17. Quantum Tasks in Minkowski Space

    E-print Network

    Adrian Kent

    2012-04-18

    The fundamental properties of quantum information and its applications to computing and cryptography have been greatly illuminated by considering information-theoretic tasks that are provably possible or impossible within non-relativistic quantum mechanics. I describe here a general framework for defining tasks within (special) relativistic quantum theory and illustrate it with examples from relativistic quantum cryptography and relativistic distributed quantum computation. The framework gives a unified description of all tasks previously considered and also defines a large class of new questions about the properties of quantum information in relation to Minkowski causality. It offers a way of exploring interesting new fundamental tasks and applications, and also highlights the scope for a more systematic understanding of the fundamental information-theoretic properties of relativistic quantum theory.

  18. Spin trap study of photoinitiations

    SciTech Connect

    Baumann, H.; Fok, N.V.; Mel-nikov, M.Y.; Timpe, J; Zubarev, V.E.

    1986-03-01

    This paper investigates the initial radical products of the photolysis of various photoinitiators of the C/sub 6/H/sub 5/CO-R type using the spin trap method and examines the possibility of using this method to obtain values of the quantum yields for radical formation and the rate constants of the elementary reactions occuring. Phenyl-tert-butylnitron (PBN) was used as the spin trap. Photoinitiators 1-15 were synthesized and purified by standard methods. The ESR spectra show that on photolysis of initiator 14 there are formed, in addition to adducts of C/sub 6/H/sub 5/CO radicals, stable triphenylmethyl radicals (C/sub 6/H/sub 3/)/sub 3/ which do not react with PBN under experimental conditions. Values are given for the quantum yields for the formation of C/sub 6/H/sub 5/CO-PBN adducts found from the initial portions of the rate curves, the quantum yields for photolysis of the initiators, and the rate constants for the reaction.

  19. Trapping efficiency of funnel and cup-traps for epigeal arthropods

    Microsoft Academic Search

    MARTIN K. OBRIST; PETER DUELLI

    Catches of six different groups of arthropods, collected in four habitat types, were analysed for the efficiency of two types of pitfall traps: plastic cups and plastic funnels. An ANOVA indicates influences of trap type, habitat and systematic group (spiders stand out) on capture success (Tab. 2). Correlation analysis of numbers captured per cm trap diameter shows significant dependence of

  20. A toroidal trap for the cold $^{87}Rb$ atoms using a rf-dressed quadrupole trap

    E-print Network

    Chakraborty, A; Ram, S P; Tiwari, S K; Rawat, H S

    2015-01-01

    We demonstrate the trapping of cold $^{87}Rb$ atoms in a toroidal geometry using a rf-dressed quadrupole magnetic trap formed by superposing a strong radio frequency (rf) field on a quadrupole trap. This rf-dressed quadrupole trap has minimum of the potential away from the quadrupole trap centre on a circular path which facilitates the trapping in the toroidal geometry. In the experiments, the laser cooled atoms were first trapped in the quadrupole trap, then cooled evaporatively using a weak rf-field, and finally trapped in the rf-dressed quadrupole trap. The radius of the toroid could be varied by varying the frequency of the dressing rf-field. It has also been demonstrated that a single rf source and an antenna can be used for the rf-evaporative cooling as well as for rf-dressing of atoms. The atoms trapped in the toroidal trap may have applications in realization of an atom gyroscope as well as in studying the quantum gases in low dimensions.

  1. Quantum mechanics in rotating-radio-frequency traps and Penning traps with a quadrupole rotating field

    SciTech Connect

    Abe, K.; Hasegawa, T. [Department of Physics, Keio University, Kanagawa 223-8522 (Japan)

    2010-03-15

    Quantum-mechanical analysis of ion motion in a rotating-radio-frequency (rrf) trap or in a Penning trap with a quadrupole rotating field is carried out. Rrf traps were introduced by Hasegawa and Bollinger [Phys. Rev. A 72, 043404 (2005)]. The classical motion of a single ion in this trap is described by only trigonometric functions, whereas in the conventional linear radio-frequency (rf) traps it is by the Mathieu functions. Because of the simple classical motion in the rrf trap, it is expected that the quantum-mechanical analysis of the rrf traps is also simple compared to that of the linear rf traps. The analysis of Penning traps with a quadrupole rotating field is also possible in a way similar to the rrf traps. As a result, the Hamiltonian in these traps is the same as the two-dimensional harmonic oscillator, and energy levels and wave functions are derived as exact results. In these traps, it is found that one of the vibrational modes in the rotating frame can have negative energy levels, which means that the zero-quantum-number state (''ground'' state) is the highest energy state.

  2. On equivalent resistance of electrical circuits

    NASA Astrophysics Data System (ADS)

    Kagan, Mikhail

    2015-01-01

    While the standard (introductory physics) way of computing the equivalent resistance of nontrivial electrical circuits is based on Kirchhoff's rules, there is a mathematically and conceptually simpler approach, called the method of nodal potentials, whose basic variables are the values of the electric potential at the circuit's nodes. In this paper, we review the method of nodal potentials and illustrate it using the Wheatstone bridge as an example. We then derive a closed-form expression for the equivalent resistance of a generic circuit, which we apply to a few sample circuits. The result unveils a curious interplay between electrical circuits, matrix algebra, and graph theory and its applications to computer science. The paper is written at a level accessible by undergraduate students who are familiar with matrix arithmetic. Additional proofs and technical details are provided in appendices.

  3. The dynamical equivalence of modified gravity revisited

    E-print Network

    Ippocratis D. Saltas; Mark Hindmarsh

    2011-01-03

    We revisit the dynamical equivalence between different representations of vacuum modified gravity models in view of Legendre transformations. The equivalence is discussed for both bulk and boundary space, by including in our analysis the relevant Gibbons-Hawking terms. In the f(R) case, the Legendre transformed action coincides with the usual Einstein frame one. We then re-express the R+f(G) action, where G is the Gauss-Bonnet term, as a second order theory with a new set of field variables, four tensor fields and one scalar and study its dynamics. For completeness, we also calculate the conformal transformation of the full Jordan frame R+f(G) action. All the appropriate Gibbons-Hawking terms are calculated explicitly.

  4. Explosive materials equivalency, test methods and evaluation

    NASA Technical Reports Server (NTRS)

    Koger, D. M.; Mcintyre, F. L.

    1980-01-01

    Attention is given to concepts of explosive equivalency of energetic materials based on specific airblast parameters. A description is provided of a wide bandwidth high accuracy instrumentation system which has been used extensively in obtaining pressure time profiles of energetic materials. The object of the considered test method is to determine the maximum output from the detonation of explosive materials in terms of airblast overpressure and positive impulse. The measured pressure and impulse values are compared with known characteristics of hemispherical TNT data to determine the equivalency of the test material in relation to TNT. An investigation shows that meaningful comparisons between various explosives and a standard reference material such as TNT should be based upon the same parameters. The tests should be conducted under the same conditions.

  5. Equivalent Carnot cycles for sorption refrigeration

    Microsoft Academic Search

    F. Meunier; P. Neveu; J. Castaing-Lasvignottes

    1998-01-01

    Temperature–entropy diagrams are usually used to describe heat-driven engines as well as vapour compressor refrigerators, but they have not yet been used for sorption refrigeration. Such Carnot cycles are introduced here to describe three sorption refrigeration technologies (liquid absorption, solid adsorption, chemical reaction). This is performed for basic cycles (without heat recovery) and for simple advanced cycles. Equivalent four-temperature Carnot

  6. The local equivalence problem in CR geometry

    Microsoft Academic Search

    Martin Kolar

    2007-01-01

    This article is dedicated to the centenary of the local CR equivalence problem, formulated by Henri Poincar\\\\'{e} in 1907. The first part gives an account of Poincar\\\\'{e}'s heuristic counting arguments, suggesting existence of infinitely many local CR invariants. Then we sketch the beautiful completion of Poincar\\\\'{e}'s approach to the problem in the work of Chern and Moser on Levi nondegenerate

  7. Quantum mechanics from an equivalence principle

    SciTech Connect

    Faraggi, A.E. [Univ. of Florida, Gainesville, FL (United States). Inst. for Fundamental Theory; Matone, M. [Univ. of Padova (Italy)

    1997-05-15

    The authors show that requiring diffeomorphic equivalence for one-dimensional stationary states implies that the reduced action S{sub 0} satisfies the quantum Hamilton-Jacobi equation with the Planck constant playing the role of a covariantizing parameter. The construction shows the existence of a fundamental initial condition which is strictly related to the Moebius symmetry of the Legendre transform and to its involutive character. The universal nature of the initial condition implies the Schroedinger equation in any dimension.

  8. Equivalent Circuit Modeling of Hysteresis Motors

    SciTech Connect

    Nitao, J J; Scharlemann, E T; Kirkendall, B A

    2009-08-31

    We performed a literature review and found that many equivalent circuit models of hysteresis motors in use today are incorrect. The model by Miyairi and Kataoka (1965) is the correct one. We extended the model by transforming it to quadrature coordinates, amenable to circuit or digital simulation. 'Hunting' is an oscillatory phenomenon often observed in hysteresis motors. While several works have attempted to model the phenomenon with some partial success, we present a new complete model that predicts hunting from first principles.

  9. II-1: Bandpass Signals Equivalent Lowpass Signals

    E-print Network

    Fowler, Mark

    the Equivalent Lowpass Signal. This is a natural generalization of the idea of phasor used in sophomore-level circuits. #12;4/26 Recall: Phasor Idea Used in Circuits Idea: Replace Acos(2 fo t+) by complex DC value Aej(2 fo t+)} = A cos(2 fo t+) + j A sin(2 fo t+) f Xl( f ) Then to get the phasor, we frequency

  10. Contextual dependencies in a stimulus equivalence paradigm

    Microsoft Academic Search

    P. Dibbets; J. H. R. Maes; J. M. H. Vossen

    2002-01-01

    Two experiments with human subjects assessed contextual dependencies in a stimulus equivalence paradigm. Subjects learned to form two sets of stimuli in a matching-to-sample training procedure. Each set was presented against one of two different background colours, the contextual cues. At test, the influence of a context change—that is, presenting each set against the other context—was measured on baseline, symmetry,

  11. Clustering in artificial categories: An equivalence analysis

    Microsoft Academic Search

    Mark Galizio; Katherine L. Stewart; Carol hPilgrim

    2001-01-01

    Category clustering is a robust finding in the free recall of familiar category members, but has rarely been studied with\\u000a artificial categories. In the present study, college students learned artificial categories via stimulus-equivalence methodology.\\u000a Arbitrary match-to-sample training with nonsense syllables established three interrelated conditional discriminations, and,\\u000a for most subjects, unreinforced test trials revealed the emergent stimulus-control relations considered to be

  12. Einstein's Apple: His First Principle of Equivalence

    E-print Network

    Engelbert L. Schucking; Eugene J. Surowitz

    2012-08-09

    After a historical discussion of Einstein's 1907 principle of equivalence, a homogeneous gravitational field in Minkowski spacetime is constructed. It is pointed out that the reference frames in gravitational theory can be understood as spaces with a flat connection and torsion defined through teleparallelism. This kind of torsion was introduced by Einstein in 1928. The concept of torsion is discussed through simple examples and some historical observations.

  13. Origins of the equivalent circuit concept: the current-source equivalent

    Microsoft Academic Search

    D. H. Johnson

    2003-01-01

    The voltage-source equivalent was first derived by Hermann von Helmholtz (1821-1894) in an 1853 paper. Exactly thirty years later in 1883, Leon Charles Thevenin (1857-1926) published the same result, apparently unaware of Helmholtz's work. The generality of the equivalent source network was not appreciated until forty-three years later. Then, in 1926, Edward Lawry Norton (1898-1983) wrote an internal Bell Laboratory

  14. [Research on NIR equivalent spectral measurement].

    PubMed

    Wang, Zhi-Hong; Liu, Jie; Sun, Yu-Yang; Teng, Fei; Lin, Jun

    2013-04-01

    When the spectra of the diffuse reflectance of low reflectivity samples or the transmittance of low transmisivity samples are measured by a portable near infrared (NIR) spectrometer, because there is the noise of the spectrometer, the smaller the reflectance or transmittance of the sample, the lower its SNR. Even if treated by denoise methods, the spectra can not meet the requirement of NIR analysis. So the equivalent spectrum measure method was researched. Based on the intensity of the reflected or transmitted signal by the sample under the traditional measure conditions, the light current of the spectrometer was enlarged, and then the signal of the measured sample increased; the reflected or transmitted light of the measure reference was reduced to avoid the signal of the measure reference over range. Moreover the equivalent spectrum of the sample was calculated in order to make it identical with the spectrum measured by traditional method. Thus the NIR spectral SNR was improved. The results of theory analysis and experiments show that if the light signal of the spectrometer was properly increased according to the reflected or transmitted signal of the low reflectivity or transmisivity sample, the equivalent spectrum was the same as the spectrum measured by traditional method and its SNR was improved. PMID:23841408

  15. Measurement equivalence in mixed mode surveys.

    PubMed

    Hox, Joop J; De Leeuw, Edith D; Zijlmans, Eva A O

    2015-01-01

    Surveys increasingly use mixed mode data collection (e.g., combining face-to-face and web) because this controls costs and helps to maintain good response rates. However, a combination of different survey modes in one study, be it cross-sectional or longitudinal, can lead to different kinds of measurement errors. For example, respondents in a face-to-face survey or a web survey may interpret the same question differently, and might give a different answer, just because of the way the question is presented. This effect of survey mode on the question-answer process is called measurement mode effect. This study develops methodological and statistical tools to identify the existence and size of mode effects in a mixed mode survey. In addition, it assesses the size and importance of mode effects in measurement instruments using a specific mixed mode panel survey (Netherlands Kinship Panel Study). Most measurement instruments in the NKPS are multi-item scales, therefore confirmatory factor analysis (CFA) will be used as the main analysis tool, using propensity score methods to correct for selection effects. The results show that the NKPS scales by and large have measurement equivalence, but in most cases only partial measurement equivalence. Controlling for respondent differences on demographic variables, and on scale scores from the previous uni-mode measurement occasion, tends to improve measurement equivalence, but not for all scales. The discussion ends with a review of the implications of our results for analyses employing these scales. PMID:25699002

  16. TNT equivalency of M10 propellant

    NASA Technical Reports Server (NTRS)

    Mcintyre, F. L.; Price, P.

    1978-01-01

    Peak, side-on blast overpressure and scaled, positive impulse have been measured for M10 single-perforated propellant, web size 0.018 inches, using configurations that simulate the handling of bulk material during processing and shipment. Quantities of 11.34, 22.7, 45.4, and 65.8 kg were tested in orthorhombic shipping containers and fiberboard boxes. High explosive equivalency values for each test series were obtained as a function of scaled distance by comparison to known pressure, arrival time and impulse characteristics for hemispherical TNT surface bursts. The equivalencies were found to depend significantly on scaled distance, with higher values of 150-100 percent (pressure) and 350-125 percent (positive impulse) for the extremes within the range from 1.19 to 3.57 m/cube root of kg. Equivalencies as low as 60-140 percent (pressure) and 30-75 percent (positive impulse) were obtained in the range of 7.14 to 15.8 m/cube root of kg. Within experimental error, both peak pressure and positive impulse scaled as a function of charge weight for all quantities tested in the orthorhombic configuration.

  17. Quantum formulation of the Einstein Equivalence Principle

    E-print Network

    Magdalena Zych; Caslav Brukner

    2015-02-03

    Validity of just a few physical conditions comprising the Einstein Equivalence Principle (EEP) suffices to ensure that gravity can be understood as space-time geometry. EEP is therefore subject to an ongoing experimental verification, with present day tests reaching the regime where quantum mechanics becomes relevant. Here we show that the classical formulation of the EEP does not apply in such a regime. The EEP requires equivalence between the total rest mass-energy of a system, the mass-energy that constitutes its inertia, and the mass-energy that constitutes its weight. In quantum mechanics internal energy is given by a Hamiltonian operator describing dynamics of internal degrees of freedom. We therefore introduce a quantum formulation of the EEP -- equivalence between the rest, inertial and gravitational internal energy operators. We show that the validity of the classical EEP does not imply the validity of its quantum formulation, which thus requires an independent experimental verification. We reanalyse some already completed experiments with respect to the quantum EEP and discuss to which extent they allow testing its various aspects.

  18. Training on integrated versus separated Stroop tasks: the progression of interference and facilitation.

    PubMed

    MacLeod, C M

    1998-03-01

    Two experiments examined the course of interference and facilitation in the Stroop (1935) task during training. Two versions of the task were compared: integrated (e.g., the word RED in the color green) and separated (e.g., green asterisks above the word RED). Stimuli were congruent (RED in red), incongruent (GREEN in red), or neutral (XXX in red). Over 5-day (Experiment 1) and 10-day (Experiment 2) training sessions, facilitation due to congruence was small, stable, and equivalent in both task versions. In contrast, interference declined sharply on the integrated task over Days 1-3, then slowed to parallel the gradual decline on the separated task. Finally, training on the color naming task did not affect a word reading task administered after training. These findings imply that (a) Stroop interference initially reflects two problems--overcoming integration and managing two conflicting information sources; (b) with practice, the larger integration problem is solved relatively quickly, rendering the integrated and separated tasks quite comparable thereafter; and (c) facilitation and interference in the Stroop task may be independent. These results challenge extant theories of the Stroop effect, which do not predict such effects. PMID:9584429

  19. Human computation tasks with global constraints

    E-print Network

    Zhang, Haoqi

    An important class of tasks that are underexplored in current human computation systems are complex tasks with global constraints. One example of such a task is itinerary planning, where solutions consist of a sequence of ...

  20. 29 CFR 541.707 - Occasional tasks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Occasional tasks. 541.707 Section 541.707 Labor ...Miscellaneous Provisions § 541.707 Occasional tasks. Occasional, infrequently recurring tasks that cannot practicably be...

  1. Vehicle Processing Readiness Course: Technical Task Analysis

    NSDL National Science Digital Library

    Alderman, J. Marvin

    This site from SpaceTEC National Aerospace Technical Education Center presents materials on technical task analysis. Topics covered include job evaluation, job equipment, task materials, personnel assigned to a task, troubleshooting, and corrective action.

  2. Black holes as trapping horizons Eric Gourgoulhon

    E-print Network

    Gourgoulhon, Eric

    Black holes as trapping horizons Eric Gourgoulhon Laboratoire Univers et Th´eories (LUTH) CNRS://www.luth.obspm.fr/~luthier/gourgoulhon/ Centrum Astronomiczne im. M. Kopernika Warsaw, Poland 17 November 2008 Eric Gourgoulhon (LUTH) Black holes as trapping horizons CAMK, Warsaw, 17 Nov. 2008 1 / 36 #12;Plan 1 Local approaches to black holes 2 Viscous

  3. Beam trapping in a modified betatron accelerator

    NASA Astrophysics Data System (ADS)

    Kapetanakos, C. A.; Dialetis, D.; Marsh, S. J.; Len, L. K.; Smith, T.

    1991-09-01

    Experimental results on the trapping of the beam in the Naval Research Laboratory modified betatron accelerator are reported. These results are in good agreement with a revised model of resistive trapping (see Sprangle and Kapetanakos, 1986). It is indicated that the wall resistivity is responsible for the inward spiral motion of the beam after injection.

  4. Space charges and traps in polymer electronics

    Microsoft Academic Search

    D. M. Taylor

    2006-01-01

    A review is undertaken of the role of space charges and traps in polymer electronic devices. The origin of the space charges considered include electrode injection leading to space-charge-limited currents in organic light emitting diodes (OLEDs), ionized impurities leading to rectification at Schottky junctions and mobile ion effects. Also considered are the effects of traps on the performance of organic

  5. Trapped radiation belts of Saturn - First look

    Microsoft Academic Search

    W. Fillius; W. H. Ip; C. E. McIlwain

    1980-01-01

    Data on the magnetosphere of Saturn obtained with the trapped radiation detector package on board the Pioneer 11 spacecraft is reported. Radiation belt profiles determined by the trapped radiation detectors on Pioneer 10 and 11 indicate that Saturn's magnetosphere is intermediate in size between those of the earth and Jupiter, with particle intensities similar to those of the earth. The

  6. Interaction between Trapped Waves and Boundary Layers

    Microsoft Academic Search

    Qingfang Jiang; James D. Doyle; Ronald B. Smith

    2006-01-01

    The absorption of trapped lee waves by the atmospheric boundary layer (BL) is investigated based on numerical simulations and theoretical formulations. It is demonstrated that the amplitude of trapped waves decays exponentially with downstream distance due to BL absorption. The decay coefficient, , defined as the inverse of the e-folding decay distance, is found to be sensitive to both surface

  7. Interaction between Trapped Waves and Boundary Layers

    Microsoft Academic Search

    Qingfang Jiang; James D. Doyle; Ronald B. Smith

    2006-01-01

    The absorption of trapped lee waves by the atmospheric boundary layer (BL) is investigated based on numerical simulations and theoretical formulations. It is demonstrated that the amplitude of trapped waves decays exponentially with downstream distance due to BL absorption. The decay coefficient, alpha, defined as the inverse of the e-folding decay distance, is found to be sensitive to both surface

  8. Cryptography, quantum computation and trapped ions

    SciTech Connect

    Hughes, Richard J.

    1998-03-01

    The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made.

  9. Atom trapping at (TRIP) KVI U Dammalapati

    E-print Network

    Rumolo, Giovanni

    : Recoil Ion Momentum Spectroscopy Calcium(Ca) MOT ALCATRAZ: Ultra sensitive isotope trap analysisVkeV eV neVAGOR cyclotron TRIµP - Trapped Radioactive Isotopes: µ-laboratories for fundamental Physics;· - angular correlations in nuclear -decay · Suitable isotope 21Na p, q 1MeV/c 260 a.u. Erecoil = (p + q)2

  10. Cryptography, Quantum Computation and Trapped Ions

    E-print Network

    Richard J. Hughes

    1997-12-23

    The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made.

  11. Trap characterization of silicon nitride thin films by a modified trap spectroscopy technique

    NASA Astrophysics Data System (ADS)

    Midya, Kousik; Dhar, Subhabrata; Kottantharayil, Anil

    2013-10-01

    Energy levels of traps in silicon nitride are determined using a modified trap spectroscopy method, based on filling of traps using electrical stress followed by optical detrapping, in a metal-silicon nitride-silicon structure. Indium tin oxide with 84% transmittance is used as transparent electrode. Photon energy dependent shift in the flat band voltage is used to estimate type and energetic position of the traps. Here, we report detection of two prominent hole trap levels at 0.5 and 1.1 eV above the valance band edge. The study suggests that phonons hardly participate in the detrapping process of holes in Si3N4.

  12. Mapping two-dimension trapping potential of nanoparticles in an optical trap

    NASA Astrophysics Data System (ADS)

    Fu, Jinxin; Hu, Yi; Zhou, Liangcheng; Lim, Min Yao; Goleb, Melissa; Zhan, Qiwen; Ou-Yang, H. Daniel

    2013-06-01

    Combining confocal microscopy and optical tweezers, we map out the spatial distribution of the particle concentrations of quantum dots, fluorescent HIV pseudo virus particles and polystyrene nanospheres in an optical trap. By analyzing the Boltzmann distribution of local particle concentrations, we obtain the two-dimension single particle trapping potential profile at the center of the optical trap in the direction perpendicular to the beam propagation. We compare the trapping potential energies of pseudo HIV vesicles and same-sized polystyrene spheres. We also compare the trapping potential energy of polystyrene spheres of a focused Gaussian beam and two modes of cylindrical vector beams.

  13. Working Memory, Task Switching, and Executive Control in the Task Span Procedure

    ERIC Educational Resources Information Center

    Logan, Gordon D.

    2004-01-01

    Four experiments explored the task span procedure: Subjects received lists of 1-10 task names to remember and then lists of 1-10 stimuli on which to perform the tasks. Task span is the number of tasks performed in order perfectly. Experiment 1 compared the task span with the traditional memory span in 6 practiced subjects and found little…

  14. On the Origins of the Task Mixing Cost in the Cuing Task-Switching Paradigm

    ERIC Educational Resources Information Center

    Rubin, Orit; Meiran, Nachshon

    2005-01-01

    Poorer performance in conditions involving task repetition within blocks of mixed tasks relative to task repetition within blocks of single task is called mixing cost (MC). In 2 experiments exploring 2 hypotheses regarding the origins of MC, participants either switched between cued shape and color tasks, or they performed them as single tasks.…

  15. The cognitive task analysis methods for job and task design: review and reappraisal

    Microsoft Academic Search

    June Wei; Gavriel Salvendy

    2004-01-01

    This paper reviews and reappraises the current research on the cognitive task analysis methodology for job or task design and analysis. Specifically, it classifies the current cognitive task analysis methods for job or task design and analysis, sorts out commonalities and differences among all these cognitive task analysis methodology for job and task design and analysis by conducting pros and

  16. Ion Trap in a Semiconductor Chip

    E-print Network

    Stick, D; Olmschenk, S; Madsen, M J; Schwab, K; Monroe, C

    2006-01-01

    The electromagnetic manipulation of isolated atoms has led to many advances in physics, from laser cooling and Bose-Einstein condensation of cold gases to the precise quantum control of individual atomic ion. Work on miniaturizing electromagnetic traps to the micrometer scale promises even higher levels of control and reliability. Compared with 'chip traps' for confining neutral atoms, ion traps with similar dimensions and power dissipation offer much higher confinement forces and allow unparalleled control at the single-atom level. Moreover, ion microtraps are of great interest in the development of miniature mass spectrometer arrays, compact atomic clocks, and most notably, large scale quantum information processors. Here we report the operation of a micrometer-scale ion trap, fabricated on a monolithic chip using semiconductor micro-electromechanical systems (MEMS) technology. We confine, laser cool, and measure heating of a single 111Cd+ ion in an integrated radiofrequency trap etched from a doped gallium...

  17. Magneto-optical trap for thulium atoms

    SciTech Connect

    Sukachev, D.; Sokolov, A.; Chebakov, K.; Akimov, A.; Kanorsky, S.; Kolachevsky, N.; Sorokin, V. [P.N. Lebedev Physical Institute, Leninsky Prospekt 53, 119991 Moscow (Russian Federation)

    2010-07-15

    Thulium atoms are trapped in a magneto-optical trap using a strong transition at 410 nm with a small branching ratio. We trap up to 7x10{sup 4} atoms at a temperature of 0.8(2) mK after deceleration in a 40-cm-long Zeeman slower. Optical leaks from the cooling cycle influence the lifetime of atoms in the magneto-optical trap which varies between 0.3 and 1.5 s in our experiments. The lower limit for the leaking rate from the upper cooling level is measured to be 22(6) s{sup -1}. The repumping laser transferring the atomic population out of the F=3 hyperfine ground-state sublevel gives a 30% increase for the lifetime and the number of atoms in the trap.

  18. Cryogenic surface-electrode ion trap apparatus

    NASA Astrophysics Data System (ADS)

    Dubielzig, Timko; Carsjens, Martina; Kohnen, Matthias; Grondkowski, Sebastian; Ospelkaus, Christian

    2014-05-01

    In this talk we describe the infrastructure necessary to operate a surface-electrode ion trap with integrated microwave conductors for near-field quantum control of 9Be+ in a cryogenic environment. These traps are promising systems for analog quantum simulators and for quantum logic applications. Our group recently developed a trap with an integrated meander-like microwave guide for driving motional sidebands on an 9Be+ ion. The trap will be operated in a cryogenic vacuum chamber. We will discuss the vibrational isolated closed cycle cryostat and the design of the vacuum chamber with all electrical supplies necessary to apply two different microwave currents, dc voltages and three independent rf supplies to generate a reconfigurable rf trapping potential. We will also discuss the used hyperfine qubit and the laser systems required to cool and repump. Furthermore we will present the cryogenic, high aperture and fully acromatic imaging system.

  19. New vanadium trap proven in commercial trials

    SciTech Connect

    Dougan, T.J. (Grace Davison, Baltimore, MD (United States)); Alkemade, U.; Lakhanpal, B. (Grace Davison, Worms (Germany)); Boock, L.T. (Grace Davison, Columbia, MD (United States))

    1994-09-26

    A vanadium trap technology called RV4+ has demonstrated in a variety of commercial fluid catalytic cracking (FCC) units its ability to reduce vanadium on equilibrium catalyst by more than 20%. Reducing vanadium loading increases microactivity and zeolite surface area retention, confirming that RV4+ protects zeolites from vanadium deactivation. Sulfur competition had prevented some previous traps from working commercially, but was not a factor with the new trap. The technology can save refiners millions of dollars per year in catalyst costs, or allow them to process feeds containing higher vanadium concentrations. The paper discusses vanadium traps, deactivation mechanism, history of traps, vanadium mobility, intraparticle mobility, interparticle mobility, measuring performance, commercial results, sulfur competition, and economic value.

  20. The habitats exploited and the species trapped in a Caribbean island trap fishery

    USGS Publications Warehouse

    Garrison, V.H.; Rogers, C.S.; Beets, J.; Friedlander, A.M.

    2004-01-01

    We visually observed fish traps in situ to identify the habitats exploited by the U.S. Virgin Islands fishery and to document species composition and abundance in traps by habitat. Fishers set more traps in algal plains than in any other habitat around St. John. Coral reefs, traditionally targeted by fishers, accounted for only 16% of traps. Traps in algal plain contained the highest number of fishes per trap and the greatest numbers of preferred food species. Traps on coral reefs contained the most species, 41 of the 59 taxa observed in the study. Acanthurus coeruleus was the most abundant species and Acanthuridae the most abundant family observed in traps. Piscivore numbers were low and few serranids were observed. Traps in algal plain contained the most fishes as a result of: ecological changes such as shifts in habitat use, mobility of species and degradation of nearshore habitat (fishery independent); and, catchability of fishes and long-term heavy fishing pressure (fishery dependent). The low number of serranids per trap, dominance of the piscivore guild by a small benthic predator, Epinephelus guttatus, and dominance of trap contents overall by a small, fast-growing species of a lower trophic guild, Acanthurus coeruleus, all point to years of intense fishing pressure.

  1. Mass trapping with MosquiTRAPs does not reduce Aedes aegypti abundance

    PubMed Central

    Degener, Carolin Marlen; de Ázara, Tatiana Mingote Ferreira; Roque, Rosemary Aparecida; Rösner, Susanne; Rocha, Eliseu Soares Oliveira; Kroon, Erna Geessien; Codeço, Cláudia Torres; Nobre, Aline Araújo; Ohly, Jörg Johannes; Geier, Martin; Eiras, Álvaro Eduardo

    2015-01-01

    The objective of this study was to evaluate the effectiveness of Aedes aegypti mass trapping using the sticky trap MosquiTRAP (MQT) by performing a cluster randomised controlled trial in Manaus, state of Amazonas, Brazil. After an initial questionnaire and baseline monitoring of adult Ae. aegypti abundance with BG-Sentinel (BGS) traps in six clusters, three clusters were randomly assigned to the intervention arm where each participating household received three MQTs for mass trapping during 17 months. The remaining three clusters (control arm) did not receive traps. The effect of mass trapping on adult Ae. aegypti abundance was monitored fortnightly with BGS traps. During the last two months of the study, a serological survey was conducted. After the study, a second questionnaire was applied in the intervention arm. Entomological monitoring indicated that MQT mass trapping did not reduce adult Ae. aegypti abundance. The serological survey indicated that recent dengue infections were equally frequent in the intervention and the control arm. Most participants responded positively to questions concerning user satisfaction. According to the results, there is no evidence that mass trapping with MQTs can be used as a part of dengue control programs. The use of this sticky trap is only recommendable for dengue vector monitoring. PMID:25946154

  2. Effects of a meaningful, a discriminative, and a meaningless stimulus on equivalence class formation.

    PubMed

    Fields, Lanny; Arntzen, Erik; Nartey, Richard K; Eilifsen, Christoffer

    2012-03-01

    Thirty college students attempted to form three 3-node 5-member equivalence classes under the simultaneous protocol. After concurrent training of AB, BC, CD, and DE relations, all probes used to assess the emergence of symmetrical, transitive, and equivalence relations were presented for two test blocks. When the A-E stimuli were all abstract shapes, none of 10 participants formed classes. When the A, B, D, and E stimuli were abstract shapes and the C stimuli were meaningful pictures, 8 of 10 participants formed classes. This high yield may reflect the expansion of existing classes that consist of the associates of the meaningful stimuli, rather than the formation of the ABCDE classes, per se. When the A-E stimuli were abstract shapes and the C stimuli became S(D)s prior to class formation, 5 out of 10 participants formed classes. Thus, the discriminative functions served by the meaningful stimuli can account for some of the enhancement of class formation produced by the inclusion of a meaningful stimulus as a class member. A sorting task, which provided a secondary measure of class formation, indicated the formation of all three classes when the emergent relations probes indicated the same outcome. In contrast, the sorting test indicated "partial" class formation when the emergent relations test indicated no class formation. Finally, the effects of nodal distance on the relatedness of stimuli in the equivalence classes were not influenced by the functions served by the C stimuli in the equivalence classes. PMID:22389524

  3. A method for trapping breeding adult American Oystercatchers

    USGS Publications Warehouse

    McGowan, C.P.; Simons, T.R.

    2005-01-01

    We present an efficient and effective method for trapping adult, breeding American Oystercatchers (Haematopus palliatus) that minimizes disturbance to nesting birds and the risk of trapping injuries. We used a remote controlled mechanical decoy to lure territorial adults to a leg-hold noose-mat trap. We trapped 25 birds over two seasons and were successful on 54% of our trapping attempts in 2003. We only trapped birds before the breeding season or between nesting attempts to reduce nest-site disturbance.

  4. Learning an L1-regularized Gaussian Bayesian network in the equivalence class space.

    PubMed

    Vidaurre, Diego; Bielza, Concha; Larrañaga, Pedro

    2010-10-01

    Learning the structure of a graphical model from data is a common task in a wide range of practical applications. In this paper, we focus on Gaussian Bayesian networks, i.e., on continuous data and directed acyclic graphs with a joint probability density of all variables given by a Gaussian. We propose to work in an equivalence class search space, specifically using the k-greedy equivalence search algorithm. This, combined with regularization techniques to guide the structure search, can learn sparse networks close to the one that generated the data. We provide results on some synthetic networks and on modeling the gene network of the two biological pathways regulating the biosynthesis of isoprenoids for the Arabidopsis thaliana plant. PMID:20083459

  5. Field Evaluation of a Novel Mos-Hole Trap and Naphtha Compared with BG Sentinel Trap and Mosquito Magnet X Trap to Collect Adult Mosquitoes.

    PubMed

    Xue, Rui-De; Smith, Michael L; Yi, Hoonbook; Kline, Daniel L

    2015-03-01

    The novel Mos-Hole trap™ with liquid attractant naphtha™ from Korea was compared with BG Sentinel™ trap and Mosquito Magnet X™ trap for field collection of adult mosquitoes in St. Johns County, northeastern Florida, from May to October 2013. The novel Mos-Hole trap baited with naphtha (liquid attractant) collected similar numbers of mosquitoes, compared with the number of mosquitoes caught by BG Sentinel traps baited with BG Lure™. Both Mos-Hole and BG Sentinel traps collected a significantly greater number of mosquitoes compared with the numbers collected by Mosquito Magnet X traps. In other field evaluations when switching lures, the Mos-Hole traps baited with BG Lure caught more mosquitoes than the BG Sentinel trap baited with liquid naphtha attractant. The results showed that the novel Mos-Hole trap has the potential to be used as an additional effective sampling tool for population surveillance and control of adult mosquitoes. PMID:25843186

  6. Exact mapping of the 2+1 Dirac oscillator onto the Jaynes-Cummings model: Ion-trap experimental proposal

    SciTech Connect

    Bermudez, A.; Martin-Delgado, M. A. [Departamento de Fisica Teorica I, Universidad Complutense, 28040 Madrid (Spain); Solano, E. [Physics Department, ASC, and CeNS, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, 80333 Munich (Germany); Seccion Fisica, Departamento de Ciencias, Pontificia Universidad Catolica del Peru, Apartado Postal 1761, Lima (Peru)

    2007-10-15

    We study the dynamics of the 2+1 Dirac oscillator exactly and find spin oscillations due to a Zitterbewegung of purely relativistic origin. We find an exact mapping of this quantum-relativistic system onto a Jaynes-Cummings model, describing the interaction of a two-level atom with a quantized single-mode field. This equivalence allows us to map a series of quantum optical phenomena onto the relativistic oscillator and vice versa. We make a realistic experimental proposal, in reach with current technology, for studying the equivalence of both models using a single trapped ion.

  7. Exact Mapping of the 2+1 Dirac Oscillator onto the Jaynes-Cummings Model: Ion-Trap Experimental Proposal

    E-print Network

    A. Bermudez; M. A. Martin-Delgado; E. Solano

    2007-04-18

    We study the dynamics of the 2+1 Dirac oscillator exactly and find spin oscillations due to a {\\it Zitterbewegung} of purely relativistic origin. We find an exact mapping of this quantum-relativistic system onto a Jaynes-Cummings model, describing the interaction of a two-level atom with a quantized single-mode field. This equivalence allows us to map a series of quantum optical phenomena onto the relativistic oscillator, and viceversa. We make a realistic experimental proposal, at reach with current technology, for studying the equivalence of both models using a single trapped ion.

  8. Trial-to-trial dynamics and learning in a generalized, redundant reaching task

    PubMed Central

    Smallwood, Rachel F.; Cusumano, Joseph P.

    2013-01-01

    If humans exploit task redundancies as a general strategy, they should do so even if the redundancy is decoupled from the physical implementation of the task itself. Here, we derived a family of goal functions that explicitly defined infinite possible redundancies between distance (D) and time (T) for unidirectional reaching. All [T, D] combinations satisfying any specific goal function defined a goal-equivalent manifold (GEM). We tested how humans learned two such functions, D/T = c (constant speed) and D·T = c, that were very different but could both be achieved by neurophysiologically and biomechanically similar reaching movements. Subjects were never explicitly shown either relationship, but only instructed to minimize their errors. Subjects exhibited significant learning and consolidation of learning for both tasks. Initial error magnitudes were higher, but learning rates were faster, for the D·T task than for the D/T task. Learning the D/T task first facilitated subsequent learning of the D·T task. Conversely, learning the D·T task first interfered with subsequent learning of the D/T task. Analyses of trial-to-trial dynamics demonstrated that subjects actively corrected deviations perpendicular to each GEM faster than deviations along each GEM to the same degree for both tasks, despite exhibiting significantly greater variance ratios for the D/T task. Variance measures alone failed to capture critical features of trial-to-trial control. Humans actively exploited these abstract task redundancies, even though they did not have to. They did not use readily available alternative strategies that could have achieved the same performance. PMID:23054607

  9. Resonance Raman spectroscopy of optically trapped functional erythrocytes

    E-print Network

    Resonance Raman spectroscopy of optically trapped functional erythrocytes Kerstin Ramser Chalmers by measurements of trapped single func- tional erythrocytes using different excitation lines (488.0, 514

  10. Graphical programming of telerobotic tasks

    SciTech Connect

    Small, D.E.; McDonald, M.J. [Sandia National Labs., Albuquerque, NM (United States). Intelligent Systems and Robotics Center

    1997-02-01

    With a goal of producing faster, safer, and cheaper technologies for nuclear waste cleanup, Sandia is actively developing and extending intelligent systems technologies. Graphical Programming is a key technology for robotic waste cleanup that Sandia is developing for this goal. This paper describes Sancho, Sandia most advanced Graphical Programming supervisory software. Sancho, now operational on several robot systems, incorporates all of Sandia`s recent advances in supervisory control. Sancho, developed to rapidly apply Graphical Programming on a diverse set of robot systems, uses a general set of tools to implement task and operational behavior. Sancho can be rapidly reconfigured for new tasks and operations without modifying the supervisory code. Other innovations include task-based interfaces, event-based sequencing, and sophisticated GUI design. These innovations have resulted in robot control programs and approaches that are easier and safer to use than teleoperation, off-line programming, or full automation.

  11. Sustained suppression in congruency tasks.

    PubMed

    Notebaert, Wim; Soetens, Eric

    2006-01-01

    In a list version of the Stroop task, Thomas observed that Stroop interference was smaller when the irrelevant word was repeated through parts of the list. MacLeod formulated the sustained-suppression hypothesis for this effect. It is assumed that the automatic response activation on the basis of the irrelevant word is selectively suppressed. In this paper this hypothesis is further investigated. In a serial Stroop task with short response-stimulus interval (RSI) we demonstrate that the Stroop effect disappears when the irrelevant word is repeated, whereas the Stroop effect is evident when the word changes. With a long RSI, there is no influence of the sequence of the irrelevant word. The same pattern of results is observed in a flanker task. The results are discussed in terms of the activation-suppression model (Ridderinkhof) and the sustained-suppression hypothesis. PMID:16556566

  12. Equivalent beam modeling using numerical reduction techniques

    NASA Technical Reports Server (NTRS)

    Chapman, J. M.; Shaw, F. H.

    1987-01-01

    Numerical procedures that can accomplish model reductions for space trusses were developed. Three techniques are presented that can be implemented using current capabilities within NASTRAN. The proposed techniques accomplish their model reductions numerically through use of NASTRAN structural analyses and as such are termed numerical in contrast to the previously developed analytical techniques. Numerical procedures are developed that permit reductions of large truss models containing full modeling detail of the truss and its joints. Three techniques are presented that accomplish these model reductions with various levels of structural accuracy. These numerical techniques are designated as equivalent beam, truss element reduction, and post-assembly reduction methods. These techniques are discussed in detail.

  13. Step (satellite Test of the Equivalence Principle)

    NASA Astrophysics Data System (ADS)

    Sumner, T. J.; Everitt, C. W. F.; Mester, J.; Torii, R.; Worden, P.; Lockerbie, N.; Pegrum, C.; Anderson, J.; Mann, G.; Blaser, J.-P.; Cruise, A. M.; Speake, C. C.; Damour, T.; Vitale, S.; Dittus, H.; Foulon, B.; Touboul, P.; Kent, B. J.; Sandford, M.; Jafry, Y.; Reinhardt, R.; Loeffler, F.; Vodel, W.

    2004-07-01

    STEP is one of a number of missions now being developed to take advantage of the quiet space environment to carry out very sensitive gravitational experiments. Using pairs of concentric free-falling proof-masses, STEP will be able to test the Equivalence Principle (EP) to a sensitivity at least five orders of magnitude better than currently achievable on ground. The EP is a founding principle of general relativity and STEP is the most sensitive experiment of this type planned so far, aiming at 1 part in 1018.

  14. Galilean equivalence for galactic dark matter.

    PubMed

    Kesden, Michael; Kamionkowski, Marc

    2006-09-29

    Satellite galaxies are tidally disrupted as they orbit the Milky Way. If dark matter (DM) experiences a stronger self-attraction than baryons, stars will preferentially gain rather than lose energy during tidal disruption, leading to an enhancement in the trailing compared to the leading tidal stream. The Sgr dwarf galaxy is seen to have roughly equal streams, challenging models in which DM and baryons accelerate differently by more than 10%. Future observations and a better understanding of DM distribution should allow detection of equivalence violation at the percent level. PMID:17026024

  15. Gravitational leptogenesis, C, CP and strong equivalence

    E-print Network

    J. I. McDonald; Graham M. Shore

    2014-11-13

    The origin of matter-antimatter asymmetry is one of the most important outstanding problems at the interface of particle physics and cosmology. Gravitational leptogenesis (baryogenesis) provides a possible mechanism through explicit couplings of spacetime curvature to appropriate lepton (or baryon) currents. In this paper, the idea that these strong equivalence principle violating interactions could be generated automatically through quantum loop effects in curved spacetime is explored, focusing on the realisation of the discrete symmetries C, CP and CPT which must be broken to induce matter-antimatter asymmetry. The related issue of quantum corrections to the dispersion relation for neutrino propagation in curved spacetime is considered within a fully covariant framework.

  16. Interdigital transducer analysis using equivalent PSpice model.

    PubMed

    Ljrba?czyk, M; Waltar, Z; Jakubik, W

    2002-06-01

    Interdigital transducers generating surface acoustic waves have found numerous applications. The present paper deals with an equivalent model of a single interdigital transducer as well as an SAW filter complying with the PSpice programme for the analysis of electronic systems. The suggested model makes it possible to take into account such effects as interelectrode reflections, losses along the acoustic path and the electromagnetic coupling between the transducers. The obtained results of the analysis of an interdigital transducer comply with the results obtained basing on an admittance model and delta-function model. The final aim is to model an SAW oscillator. PMID:12109551

  17. Final Report Supplement - Task 3: Task Analysis Data Collection

    Microsoft Academic Search

    Steven Kiger; Thomas Rockwell; Steve Niswonger; Thomas Nygren

    16. Abstract This technical report consists of a collection of task analytic data to support heavy vehicle driver workload assessment and protocol development. Data were collected from professional drivers to provide insights into the following issues: the meaning of the term 'workload' to heavy vehicle drivers (N = 41 drivers interviewed); the demand placed on drivers (N = 55) by

  18. Advanced Topics in AI Task Allocation-Task Allocation -

    E-print Network

    Institute for SoftwareTechnology Inffeldgasse 16b/2 A 8010 GA-8010 Graz Austria #12;Agenda Motivation Examples Motivation Examples Formal Problem Description T f T k All ti Taxonomy of Task Allocation passable (police) ­ extinguish the fires (fire brigades) ­ rescue all civilians (ambulances

  19. Interaction Effects of Task Variables and Ability on Task Engagement.

    ERIC Educational Resources Information Center

    Redfield, Doris L.; Roenker, Daniel L.

    Recent research findings have shown a positive relationship between achievement and the amount of time students engage in learning activities. Since the greatest percentage of class time is allocated to seatwork, with worksheets being the most frequently used activity, a study investigated the effects of using three types of worksheet tasks on…

  20. Dose rate, dose-equivalent rate, and quality factor in SLS-1

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Braby, L. A.; Cucinotta, F. A.; Atwell, W.

    1992-01-01

    A tissue-equivalent proportional counter (TEPC) sensitive to the lineal energy range of 0.26-300 keV micrometer-1 was flown on STS-40 (39 degrees x 278 km x 296 km) inside the Spacelab. This instrument was previously flown on STS-31 but was modified to provide a finer resolution at lower lineal energies to better map the South Atlantic Anomaly (SAA) protons. The instrument was turned on 6 June 1991, and operated for 7470 min (124.5 h). The flight duration was characterized by a very large number of X-ray solar flares and enhanced magnetic field fluctuations; however, no significant dose from the solar particles was measured at the location of this instrument. The flight data can be separated into trapped and galactic cosmic radiation parts. The dose rate, dose-equivalent rate and quality factor for trapped radiation were 4.21 +/- 0.03 mrad day-1, 7.72 +/- 0.05 mrem day-1, and 1.83 +/- 0.1, respectively. The dose rate, dose-equivalent rate, and quality factor for galactic cosmic radiation were 5.34 +/- 0.03 mrad day-1, 14.63 +/- 0.06 mrem day-1, and 2.74 +/- 0.1, respectively. The overall quality factor for the flight was 2.38. The dose from the GCR is higher than from SAA protons because of the high inclination and low altitude of this flight. The AP8MAX model of the trapped radiation gives a dose rate of 2.43 mrad day-1 and a quality factor of 1.77. The CREME solar maximum model of galactic cosmic radiation gives a dose rate of 2.54 mrad day-1 and a quality factor of 2.91. Thus the AP8MAX model underestimates the dose by a factor of 1.8 whereas the CREME model leads to an underestimation of the dose by a factor of 2. A comparison of the LET spectra using the AP8MAX model and galactic cosmic radiation transport codes shows only a qualitative agreement.

  1. Magnetic Trapping of Metastable Calcium Atoms

    E-print Network

    Dirk P. Hansen; Janis R. Mohr; Andreas Hemmerich

    2003-01-27

    Metastable calcium atoms, produced in a magneto-optic trap (MOT) operating within the singlet system, are continuously loaded into a magnetic trap formed by the magnetic quadrupole field of the MOT. At MOT temperatures of 3 mK and 240 ms loading time we observe 1.1 x 10^8 magnetically trapped 3P2 atoms at densities of 2.4 x 10^8 cm^-3 and temperatures of 0.61 mK. In a modified scheme we first load a MOT for metastable atoms at a temperature of 0.18 mK and subsequently release these atoms into the magnetic trap. In this case 240 ms of loading yields 2.4 x 10^8 trapped 3P2 atoms at a peak density of 8.7 x 10^10 cm^-3 and a temperature of 0.13 mK. The temperature decrease observed in the magnetic trap for both loading schemes can be explained only in part by trap size effects.

  2. Single-molecule dynamics in nanofabricated traps

    NASA Astrophysics Data System (ADS)

    Cohen, Adam

    2009-03-01

    The Anti-Brownian Electrokinetic trap (ABEL trap) provides a means to immobilize a single fluorescent molecule in solution, without surface attachment chemistry. The ABEL trap works by tracking the Brownian motion of a single molecule, and applying feedback electric fields to induce an electrokinetic motion that approximately cancels the Brownian motion. We present a new design for the ABEL trap that allows smaller molecules to be trapped and more information to be extracted from the dynamics of a single molecule than was previously possible. In particular, we present strategies for extracting dynamically fluctuating mobilities and diffusion coefficients, as a means to probe dynamic changes in molecular charge and shape. If one trapped molecule is good, many trapped molecules are better. An array of single molecules in solution, each immobilized without surface attachment chemistry, provides an ideal test-bed for single-molecule analyses of intramolecular dynamics and intermolecular interactions. We present a technology for creating such an array, using a fused silica plate with nanofabricated dimples and a removable cover for sealing single molecules within the dimples. With this device one can watch the shape fluctuations of single molecules of DNA or study cooperative interactions in weakly associating protein complexes.

  3. Preparation time modulates pro-active control and enhances task conflict in task switching.

    PubMed

    Kalanthroff, Eyal; Henik, Avishai

    2014-03-01

    Performance in the Stroop task reflects two conflicts--informational (between the incongruent word and ink color) and task (between relevant color naming and irrelevant word reading). Neuroimaging findings support the existence of task conflict in congruent trials. A behavioral indication for task conflict--Stroop reverse facilitation--was found in previous studies under low task-control conditions. Task switching also causes reduction in task control because the task set frequently changes. We hypothesized that it would be harder to efficiently manage task conflicts in switching situations and, specifically, as cue-target interval (CTI) decreases. This suggestion was examined in two experiments using a combined Stroop task-switching design. We found a large interference effect and reverse facilitation that decreased with elongation of CTI. Results imply that task switching reduces pro-active task control and thereby enhances the informational and the task conflicts. This calls for a revision of recent control models to include task conflict. PMID:23712333

  4. Counting Problems Computationally Equivalent to Computing the Determinant

    E-print Network

    Portier, Natacha

    Counting Problems Computationally Equivalent to Computing the Determinant Seinosuke Toda Technical Computationally Equivalent to Computing the Determinant (author) Seinosuke Toda (affiliation) Department, Japan 1 #12;(abbreviated title) Counting Problems and the Determinant (mailing address) Seinosuke Toda

  5. 14 CFR 21.461 - Equivalent safety provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...PRODUCTS AND PARTS Designated Alteration Station Authorization Procedures § 21.461 Equivalent safety provisions. The DAS shall obtain the Administrator's concurrence on the application of all equivalent safety provisions applied under §...

  6. 14 CFR 21.461 - Equivalent safety provisions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...PRODUCTS AND PARTS Designated Alteration Station Authorization Procedures § 21.461 Equivalent safety provisions. The DAS shall obtain the Administrator's concurrence on the application of all equivalent safety provisions applied under §...

  7. Elementary equivalence of Chevalley groups over local rings

    SciTech Connect

    Bunina, Elena I [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)

    2010-05-11

    It is proved that (elementary) Chevalley groups over local rings with invertible 2 are elementarily equivalent if and only if their types and weight lattices coincide and the initial rings are elementarily equivalent. Bibliography: 25 titles.

  8. 49 CFR 396.23 - Equivalent to periodic inspection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Equivalent to periodic inspection. 396.23 Section 396...MAINTENANCE § 396.23 Equivalent to periodic inspection. (a) A motor carrier...performed in accordance with the minimum periodic inspection standards set forth...

  9. 49 CFR 396.23 - Equivalent to periodic inspection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Equivalent to periodic inspection. 396.23 Section 396...MAINTENANCE § 396.23 Equivalent to periodic inspection. (a) A motor carrier...performed in accordance with the minimum periodic inspection standards set forth...

  10. 49 CFR 396.23 - Equivalent to periodic inspection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Equivalent to periodic inspection. 396.23 Section 396...MAINTENANCE § 396.23 Equivalent to periodic inspection. (a) A motor carrier...performed in accordance with the minimum periodic inspection standards set forth...

  11. 49 CFR 396.23 - Equivalent to periodic inspection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Equivalent to periodic inspection. 396.23 Section 396...MAINTENANCE § 396.23 Equivalent to periodic inspection. (a) A motor carrier...performed in accordance with the minimum periodic inspection standards set forth...

  12. 49 CFR 396.23 - Equivalent to periodic inspection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Equivalent to periodic inspection. 396.23 Section 396...MAINTENANCE § 396.23 Equivalent to periodic inspection. (a) A motor carrier...performed in accordance with the minimum periodic inspection standards set forth...

  13. Task Assignment Heuristics for Distributed CFD Applications

    Microsoft Academic Search

    Noé Lopez-benitez; M. Jahed Djomehri; Rupak Biswas

    2001-01-01

    This paper proposes a task graph (TG) model to represent a single discrete step of a computational fluid dynamics (CFD) application. The TG model is then used to predict the performance of a set of task assignment heuristics developed based on the constraints inherent in the CFD problem. Two primitive assignments, the Largest Task First and the Minimum Task First,

  14. Trapping Rydberg Atoms in an Optical Lattice

    NASA Astrophysics Data System (ADS)

    Anderson, Sarah E.

    2012-06-01

    Optical lattice traps for Rydberg atoms are of interest in advanced science and in practical applications. After a brief discussion of these areas of interest, I will review some basics of optical Rydberg-atom trapping. The trapping potential experienced by a Rydberg atom in an optical lattice is given by the spatial average of the free-electron ponderomotive energy weighted by the Rydberg electron's probability distribution. I will then present experimental results on the trapping of ^85Rb Rydberg atoms in a one-dimensional ponderomotive optical lattice (wavelength 1064 nm). The principal methods employed to study the lattice performance are microwave spectroscopy, which is used to measure the lattice's trapping efficiency, and photo-ionization, which is used to measure the dwell time of the atoms in the lattice. I have achieved a 90% trapping efficiency for ^85Rb 50S atoms by inverting the lattice immediately after laser excitation of ground-state atoms into Rydberg states. I have characterized the dwell time of the atoms in the lattice using photo-ionization of 50D5/2 atoms. In continued work, I have explored the dependence of the Rydberg-atom trapping potential on the angular portion of the atomic wavefunction. Distinct angular states exhibit different trapping behavior in the optical lattice, depending on how their wavefunctions are oriented relative to the lattice planes. Specifically, I have measured the lattice potential depth of sublevels of ^85Rb nD atoms (50<=n<=65) in a one-dimensional optical lattice with a transverse DC electric field. The trapping behavior varies substantially for the various angular sublevels, in agreement with theory. The talk will conclude with an outlook into planned experiments.

  15. Laser trapping of {sup 21}Na atoms

    SciTech Connect

    Lu, Zheng-Tian

    1994-09-01

    This thesis describes an experiment in which about four thousand radioactive {sup 21}Na (t{sub l/2} = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped {sup 21}Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of {sup 21}Na {yields} {sup 21}Ne + {Beta}{sup +} + v{sub e}, which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, {sup 21}Na atoms were produced by bombarding {sup 24}Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The {sup 21}Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined.

  16. Equivalence of trans paths in ion channels

    NASA Astrophysics Data System (ADS)

    Alvarez, Juan; Hajek, Bruce

    2006-04-01

    We explore stochastic models for the study of ion transport in biological cells. Analysis of these models explains and explores an interesting feature of ion transport observed by biophysicists. Namely, the average time it takes ions to cross certain ion channels is the same in either direction, even if there is an electric potential difference across the channels. It is shown for simple single ion models that the distribution of a path (i.e., the history of location versus time) of an ion crossing the channel in one direction has the same distribution as the time-reversed path of an ion crossing the channel in the reverse direction. Therefore, not only is the mean duration of these paths equal, but other measures, such as the variance of passage time or the mean time a path spends within a specified section of the channel, are also the same for both directions of traversal. The feature is also explored for channels with interacting ions. If a system of interacting ions is in reversible equilibrium (net flux is zero), then the equivalence of the left-to-right trans paths with the time-reversed right-to-left trans paths still holds. However, if the system is in equilibrium, but not reversible equilibrium, then such equivalence need not hold.

  17. Functional equivalence and spatial path memory.

    PubMed

    Lyon, Don R; Gunzelmann, Glenn M

    2011-11-01

    Loomis, Klatzky, Avraamides, Lippa and Golledge ( 2007 ) suggest that, when it comes to spatial information, verbal description and perceptual experience are nearly functionally equivalent with respect to the cognitive representations they produce. We tested this idea for the case of spatial memory for complex paths. Paths consisted entirely of unit-length segments followed by 90-degree turns, thus assuring that a path could be described with equal precision using either an egocentric verbal description or a virtual self-motion experience. The verbal description was analogous to driving directions (e.g., turn left and go one block, then turn right, etc.) except in three dimensions (allowing rotation followed by up or down movement). Virtual self-motion was depicted as first-person travel through a 3D grid of featureless corridors. Comparison of these two conditions produced a result that may be surprising to some, but nevertheless appears to support the notion of functional equivalence: Virtual self-motion does not produce better path memory than verbal description, when care is taken to present equally precise path information. This result holds for even very complex paths and despite evidence from proximity-based interference that the memory representation of the path is spatial. PMID:22044400

  18. THE NONEQUIVALENT HEALTH OF HIGH SCHOOL EQUIVALENTS

    PubMed Central

    Zajacova, Anna; Everett, Bethany G.

    2014-01-01

    Objectives Millions of U.S. adults are recipients of the high school equivalency (GED) diploma. Virtually nothing is known about the health of this large group, although literature suggests GED recipients are considerably worse off than high school graduates in numerous economic and social outcomes. We analyze general health among working-age adults with a high school diploma, GED recipients, and high school dropouts. Methods Ordered and binary logistic models of self-rated health and activity limitations were estimated using data from the 1997–2009 National Health Interview Surveys (N=76,703). Results GED recipients have significantly and substantially worse health than high school graduates, among both sexes. In fact, the GED recipients’ health is generally comparable to that of high school dropouts. Health behaviors and economic factors explain a large proportion of the difference but the gap remains significant. Conclusions In terms of health, adults with a terminal GED are not equivalent to high school graduates. GED recipients report considerably worse general health and activity limitations. The disadvantage is only partly due to the worse economic outcomes and health behaviors; a significant difference remains unexplained and may be due to other, unobserved pathways, or to selection mechanisms. PMID:25076799

  19. The role of metacognition in prospective memory: anticipated task demands influence attention allocation strategies.

    PubMed

    Rummel, Jan; Meiser, Thorsten

    2013-09-01

    The present study investigates how individuals distribute their attentional resources between a prospective memory task and an ongoing task. Therefore, metacognitive expectations about the attentional demands of the prospective-memory task were manipulated while the factual demands were held constant. In Experiments 1a and 1b, we found attentional costs from a prospective-memory task with low factual demands to be significantly reduced when information about the low to-be-expected demands were provided, while prospective-memory performance remained largely unaffected. In Experiment 2, attentional monitoring in a more demanding prospective-memory task also varied with information about the to-be-expected demands (high vs. low) and again there were no equivalent changes in prospective-memory performance. These findings suggest that attention-allocation strategies of prospective memory rely on metacognitive expectations about prospective-memory task demands. Furthermore, the results suggest that attentional monitoring is only functional for prospective memory to the extent to which anticipated task demands reflect objective task demands. PMID:23860302

  20. Effects of a Foot Placement Constraint on Use of Motor Equivalence during Human Hopping

    PubMed Central

    Auyang, Arick G.; Chang, Young-Hui

    2013-01-01

    Humans can robustly locomote over complex terrains even while simultaneously attending to other tasks such as accurate foot placement on the ground. We investigated whether subjects would exploit motor redundancy across the joints of the leg to stabilize overall limb kinematics when presented with a hopping task that constrained foot placement position. Subjects hopped in place on one leg (2.2 Hz) while having to place their foot into one of three target sizes upon landing (0.250, 0.063, 0.010 m2). As takeoff and landing angles are critical to this task performance, we hypothesized smaller target sizes would increase the need to stabilize (i.e., make more consistent) the leg orientation through motor equivalent combinations of segment angles. As it was not critical to the targeting task, we hypothesized no changes for leg length stabilization across target size. With smaller target sizes, we saw total segment angle variance increase due to greater signal-dependent noise associated with an increased activation of leg extensor muscles (medial and lateral gastrocnemius, vastus medialis, vastus lateralis and rectus femoris). At smaller target sizes, more segment angle variance was aligned to kinematic deviations with the goal of maintaining leg orientation trajectory. We also observed a decrease in the variance structure for stabilizing leg length at the smallest target conditions. This trade-off effect is explained by the nearly orthogonal relationship between the two goal-equivalent manifolds for leg length vs. leg orientation stabilization. Our results suggest humans increasingly rely on kinematic redundancy in their legs to achieve robust, consistent locomotion when faced with novel conditions that constrain performance requirements. These principles may generalize to other human locomotor gaits and provide important insights into the control of the legs during human walking and running. PMID:23936013