Science.gov

Sample records for actual response time

  1. Functional equivalence for response programming of actually performing versus imagining movements.

    PubMed

    Ito, M

    1999-06-01

    The present study was conducted to test the hypothesis that response programming occurs when movements are only imagined. 12 subjects were required to react and produce the sequence of same or different force by squeezing a handle as quickly and accurately as possible after the two reaction signals which were separated by the interstimulus interval of 1 sec. The reaction time to initiate the second response was examined when the first response is covertly performed, but the second response is actually performed. The reaction times to initiate the second responses were significantly shorter for imagining and actually performing different movements or the control condition. There was no significant difference in reaction time between the conditions with the same movements. These findings were interpreted as evidence for functional equivalence for response programming of actually performing versus imagining movements. PMID:10407903

  2. Response to actual and simulated recordings of conventional takeoff and landing jet aircraft

    NASA Technical Reports Server (NTRS)

    Mabry, J. E.; Sullivan, B. M.

    1978-01-01

    Comparability between noise characteristics of synthesized recordings of aircraft in flight and actual recordings were investigated. Although the synthesized recordings were more smoothly time-varying than the actual recordings and the synthesizer could not produce a comb-filter effect that was present in the actual recordings, results supported the conclusion that annoyance response is comparable to the synthesized and actual recordings. A correction for duration markedly improved the validity of engineering calculation procedures designed to measure noise annoyance. Results led to the conclusion that the magnitude estimation psychophysical method was a highly reliable approach for evaluating engineering calculation procedures designed to measure noise annoyance. For repeated presentations of pairs of actual recordings, differences between judgment results for identical signals ranged from 0.0 to 0.5 db.

  3. Let's not, and say we would: imagined and actual responses to witnessing homophobia.

    PubMed

    Crosby, Jennifer Randall; Wilson, Johannes

    2015-01-01

    We compared imagined versus actual affective and behavioral responses to witnessing a homophobic slur. Participants (N = 72) witnessed a confederate using a homophobic slur, imagined the same scenario, or were not exposed to the slur. Those who imagined hearing the slur reported significantly higher levels of negative affect than those who actually witnessed the slur, and nearly one half of them reported that they would confront the slur, whereas no participants who actually heard the slur confronted it. These findings reveal a discrepancy between imagined and real responses to homophobic remarks, and they have implications for the likelihood that heterosexuals will actually confront homophobic remarks.

  4. Pacing strategy in simulated cycle time-trials is based on perceived rather than actual distance.

    PubMed

    Nikolopoulos, V; Arkinstall, M J; Hawley, J A

    2001-06-01

    This study determined the pacing strategies and performance responses of six well-trained cyclists/triathletes (peak O2 uptake 66.4+/-3.7 ml x kg(-1) x min(-1), mean+/-SD) during seven simulated time-trials (TT) conducted on a wind-braked cycle ergometer. All subjects first performed a 40 km familiarisation ride (TT1). They were then informed they would be riding a further four 40 km TT for the purpose of a reliability study. Instead, the actual distances ridden for the next three TT were a random order of 34 (TT2), 40 (TT3) and 46 km (TT4). The only feedback given to subjects during TT1-4 was the percentage distance of that ride remaining. During a further 40 km TT (TT5) subjects were allowed to view their heart rate (HR) responses throughout the ride. Despite the significantly different performance times across the three distances (47:23+/-4:23 vs 55:57+/-3:24 vs 65:41+/-3:56 min for the 34, 40 and 46 km respectively, P<0.001), average power output (296+/-48 vs 294+/-48 vs 286+/-40 W) and HR (173+/-11 vs 174+/-12 vs 173+/-12 beats x min(-1)) were similar. The true nature of the first part of the study was then revealed to subjects who subsequently completed an additional 34 km and 46 km TT TT6-7) in which the actual and perceived distance ridden was the same. Power output and HR responses were similar for both unknown (TT2 and TT6) and known (TT4 and TT7) rides for both distances: 296+/-48 vs 300+/-55 W and 173+/-11 vs 177+/-11 beats x min(-1) (34 km) and 286+/-40 vs 273+/-42 W and 173+/-12 vs 174+/-12 beats x min(-1) (46 km). In conclusion, well-trained cyclists rode at similar power outputs and HR during time trials they perceived to be the same distance, but which varied in actual distance from 34 to 46 km.

  5. 33 CFR 142.4 - Duties of lessees, permittees, and persons responsible for actual operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Duties of lessees, permittees, and persons responsible for actual operations. 142.4 Section 142.4 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES...

  6. Testing two temporal upscaling schemes for the estimation of the time variability of the actual evapotranspiration

    NASA Astrophysics Data System (ADS)

    Maltese, A.; Capodici, F.; Ciraolo, G.; La Loggia, G.

    2015-10-01

    Temporal availability of grapes actual evapotranspiration is an emerging issue since vineyards farms are more and more converted from rainfed to irrigated agricultural systems. The manuscript aims to verify the accuracy of the actual evapotranspiration retrieval coupling a single source energy balance approach and two different temporal upscaling schemes. The first scheme tests the temporal upscaling of the main input variables, namely the NDVI, albedo and LST; the second scheme tests the temporal upscaling of the energy balance output, the actual evapotranspiration. The temporal upscaling schemes were implemented on: i) airborne remote sensing data acquired monthly during a whole irrigation season over a Sicilian vineyard; ii) low resolution MODIS products released daily or weekly; iii) meteorological data acquired by standard gauge stations. Daily MODIS LST products (MOD11A1) were disaggregated using the DisTrad model, 8-days black and white sky albedo products (MCD43A) allowed modeling the total albedo, and 8-days NDVI products (MOD13Q1) were modeled using the Fisher approach. Results were validated both in time and space. The temporal validation was carried out using the actual evapotranspiration measured in situ using data collected by a flux tower through the eddy covariance technique. The spatial validation involved airborne images acquired at different times from June to September 2008. Results aim to test whether the upscaling of the energy balance input or output data performed better.

  7. Modelling bulk surface resistance from MODIS time series data to estimate actual regional evapotranspiration

    NASA Astrophysics Data System (ADS)

    Autovino, Dario; Minacapilli, Mario; Provenzano, Giuseppe

    2015-04-01

    Estimation of actual evapotraspiration by means of Penman-Monteith (P-M) equation requires the knowledge of the so-called 'bulk surface resistance', rc,act, representing the vapour flow resistance through the transpiring crop and evaporating soil surface. The accurate parameterization of rc,act still represents an unexploited topic, especially in the case of heterogeneous land surface. In agro-hydrological applications, the P-M equation commonly used to evaluate reference evapotranspiration (ET0) of a well-watered 'standardized crop' (grass or alfalfa), generally assumes for the bulk surface resistance a value of 70 s m-1. Moreover, specific crop coefficients have to be used to estimate maximum and/or actual evapotranspiration based on ET0. In this paper, a simple procedure for the indirect estimation of rc,act as function of a vegetation index computed from remote acquisition of Land Surface Temperature (LST), is proposed. An application was carried out in an irrigation district located near Castelvetrano, in South-West of Sicily, mainly cultivated with olive groves, in which actual evapotranspiration fluxes were measured during two years (2010-2011) by an Eddy Covariance flux tower (EC). Evapotranspiration measurements allowed evaluating rc,actbased on the numerical inversion of the P-M equation. In the same study area, a large time series of MODIS LST data, characterized by a spatial resolution of 1x1 km and a time step of 8-days, was also acquired for the period from 2000 to 2014. A simple Vegetation Index Temperatures (VTI), with values ranging from 0 to 1, was computed using normalized LST values. Evapotranspiration fluxes measured in 2010 were used to calibrate the relationship between rc,act and VTI, whereas data from 2011 were used for its validation. The preliminary results evidenced that, for the considered crop, an almost constant value of rc,act, corresponding to about 250 s m-1, can be considered typical of periods in which the crop is well

  8. Response times to conceptual questions

    NASA Astrophysics Data System (ADS)

    Lasry, Nathaniel; Watkins, Jessica; Mazur, Eric; Ibrahim, Ahmed

    2013-09-01

    We measured the time taken by students to respond to individual Force Concept Inventory (FCI) questions. We examine response time differences between correct and incorrect answers, both before and after instruction. We also determine the relation between response time and expressed confidence. Our data reveal three results of interest. First, response times are longer for incorrect answers than for correct ones, indicating that distractors are not automatic choices. Second, response times increase after instruction for both correct and incorrect answers, supporting the notion that instruction changes students' approach to conceptual questions. Third, response times are inversely related to students' expressed confidence; the lower their confidence, the longer it takes to respond.

  9. Education and Decision Making at the Time of Triptan Prescribing: Patient Expectations vs Actual Practice

    PubMed Central

    Mathew, Paul G.; Pavlovic, Jelena M.; Lettich, Alyssa; Wells, Rebecca E.; Robertson, Carrie E.; Mullin, Kathleen; Charleston, Larry; Dodick, David W.; Schwedt, Todd J.

    2014-01-01

    Background Optimizing patient satisfaction with their medical care and maximizing patient adherence with treatment plans requires an understanding of patient preferences regarding education and their role in decision making when treatments are prescribed. Objective To assess the congruence between patient expectations and actual practice regarding education and decision making at the time a triptan is prescribed. Methods This multicenter cross-sectional survey was performed by headache fellow members of the American Headache Society Headache Fellows Research Consortium at their respective tertiary care headache clinics. Migraine patients who were new patients to the headache clinic and who were current triptan users (use within prior 3 months and for ≥1 year) or past triptan users (no use within 6 months; prior use within 2 years) completed questionnaires that assessed the education they received and their role in decision making at the time a triptan was first prescribed as well as their desire for education and participation in decision making when a triptan is prescribed. Results Consistent with patient preference, most participants received the majority of their education about the triptan from the prescriber's office (70.2%). In descending rank order, participants most desired to be informed about how to decide if a triptan should be taken, when during the course of migraine a triptan should be taken, possible side effects, cost, and how to obtain refills. Regarding side effects, most participants preferred to receive education about the most common side effects of a triptan rather than addressing all possible side effects. Regarding triptan dosing, participants desired to be informed in descending order of importance about taking other medications with triptans, how many doses can be taken for each migraine, how many doses can be taken each week/month, what to do if the triptan does not work, and the triptan mechanism of action. The vast majority of

  10. Time interval moderates the relationship between psyching-up and actual sprint performance.

    PubMed

    Hammoudi-Nassib, Sarra; Chtara, Moktar; Nassib, Sabri; Briki, Walid; Hammoudi-Riahi, Sabra; Tod, David; Chamari, Karim

    2014-11-01

    This study attempted to test whether the strongest effect of psyching-up (PU) strategy on actual sprint performance can be observed when the strategy is used immediately (or almost) before performance compared with when there is a delay between PU and performance. To do so, 16 male sprinters (age, 20.6 ± 1.3 years; body mass, 77.5 ± 7.1 kg; height, 180.8 ± 5.6 cm) were enrolled in a counterbalanced experimental design in which participants were randomly assigned to 10 sessions (2 [Experimental Condition: imagery vs. distraction] × 5 [Time Intervals: no interval, 1 minute, 2 minutes, 3 minutes, and 5 minutes]). Before performing the experimental tasks, participants rated: (a) the Hooper index, (b) their degree of self-confidence, and (c) after the completion of the experimental test; they rated their perceived effort. Findings showed that the imagery significantly improved sprint performance. Specifically, the imagery enhanced performance on the phase of acceleration (0-10 m) and on the overall sprint (0-30 m) when used immediately before performance and at 1- and 2-minute intervals but not for 3- and 5-minute intervals. These findings support the hypothesis that the potential effect of the PU strategy on performance vanishes over time. The pre-experimental task Hooper and self-efficacy indexes did not change across the 10 experimental sessions, reinforcing the view that the observed performance changes were directly caused by the experimental manipulation and not through any altered status of the athletes (self-efficacy, fatigue/recovery, and stress). The potential mechanisms underlying such a process and practical applications are discussed.

  11. Virologic response and haematologic toxicity of boceprevir- and telaprevir-containing regimens in actual clinical settings

    PubMed Central

    Butt, A. A.; Yan, P.; Shaikh, O. S.; Freiberg, M. S.; Re, V. Lo; Justice, A. C.; Sherman, K. E.

    2016-01-01

    SUMMARY Effectiveness, safety and tolerability of boceprevir (BOC) and telaprevir (TPV) in actual clinical settings remain unknown. We determined rates of sustained virologic response (SVR) and haematologic adverse effects among persons treated with BOC- or TPV-containing regimens, compared with pegylated interferon/ribavirin (PEG/RBV). Using an established cohort of hepatitis C virus (HCV)-infected persons, Electronically Retrieved Cohort of HCV Infected Veterans (ERCHIVES), we identified those treated with a BOC- or TPV-containing regimen and HCV genotype 1-infected controls treated with PEG/RBV. We excluded those with HIV co-infection and missing HCV RNA values to determine SVR. Primary endpoints were SVR (undetectable HCV RNA ≥12 weeks after treatment completion) and haematologic toxicity (grade 3/4 anaemia, neutropenia and thrombocytopenia). We evaluated 2288 persons on BOC-, 409 on TPV-containing regimen and 6308 on PEG/RBV. Among these groups, respectively, 31%, 43% and 9% were treatment-experienced; 17%, 37% and 14% had baseline cirrhosis; 63%, 54% and 48% were genotype 1a. SVR rates among noncirrhotics were as follows: treatment naïve: 65% (BOC), 67% (TPV) and 31% (PEG/RBV); treatment experienced: 57% (BOC), 54% (TPV) and 13% (PEG/RBV); (P-value not significant for BOC vs TPV; P < 0.0001 for BOC or TPV vs PEG/RBV). Haematologic toxicities among BOC-, TPV- and PEG/RBV-treated groups were as follows: grade 3/4 anaemia 7%, 11% and 3%; grade 4 thrombocytopenia 2.2%, 5.4% and 1.7%; grade 4 neutropenia 8.2%, 5.6% and 3.4%. SVR rates are higher and closer to those reported in pivotal clinical trials among BOC- and TPV-treated persons compared with PEG/RBV-treated persons. Haematologic adverse events are frequent, but severe toxicity is uncommon. PMID:25524834

  12. Effect of 11 months of yoga training on cardiorespiratory responses during the actual practice of Surya Namaskar

    PubMed Central

    Sinha, Biswajit; Sinha, Tulika Dasgupta

    2014-01-01

    Background: Surya Namaskar (SN), a popular traditional Indian yogic practice, includes practicing 12 physical postures with alternate forward and backward bending movement of the body along with deep breathing maneuvers. The practice of SN has become popular among yoga practitioners and other fitness conscious people. The long-term effect of practicing SN and other yogic practices on cardiorespiratory responses during SN are lacking. Aim: The present study was conducted to study the effect of yogic training on various cardiorespiratory responses during the SN practice in yoga trainees after a time interval of 3, 6, and 11 months. Materials and Methods: The present study was conducted on 9 healthy male Army soldiers who underwent training in various yoga postures including SN, meditation, and pranayama for 1 h daily for 11 months. First, second, and third phase of the study was conducted in the laboratory after completion of 3, 6, and 11 months of the yoga training. The participants performed SN along with other yogic practices in the laboratory as per their daily practice schedule. The cardiorespiratory responses of the volunteers were recorded during actual practice of SN. Statistical Analysis: One-way repeated measure ANOVA followed by Tukey HSD. Results: Oxygen consumption and heart rate during actual practice of SN was 0.794 ± 0.252, 0.738 ± 0.229, and 0.560 ± 0.165 L/min and 92.1 ± 11.6, 97.9 ± 7.3 and 87.4 ± 9.2 beats/min respectively at 1st , 2nd , and 3rd phase of yoga training. Minute ventilation and tidal volume also reduced from 19.9 ± 4.65 to 17.8 ± 4.41 L/min and 1.091 ± 0.021 to 0.952 L/breath from 1st phase to 3rd phase of yoga training. However, respiratory parameters like breathing rate (fR) did not show any reduction across the three phases. Conclusion: The results of the present study indicated that yogic training caused conditioning of cardiorespiratory parameters except fR, which did not reduce across three phases of training. PMID

  13. Integration of Remote Sensing derived Actual Evapotranspiration with Meteorological Data for Real Time Demand Forecasting in Semi-arid Regions

    NASA Astrophysics Data System (ADS)

    Ullah, M. K.; Hafeez, M. M.; Chemin, Y.; Faux, R.; Sixsmith, J.

    2010-12-01

    Irrigated agriculture is major consumer of fresh water, but a large part of the water devour for irrigation is wasted due to poor management of irrigation systems. Improving water management in irrigated areas require the analysis of real time water demand in order to determine the possibilities in which it may be modified and rationalised. Real time water demand information in irrigated areas is a key for planning about sustainable use of irrigation water. These activities are needed not only to improve water productivity, but also to increase the sustainability of irrigated agriculture by saving irrigation water. Demand forecasting entail the complete understanding of spatial and expected temporal variability of metrological parameters and evapotranspiration (ET). ET is the overriding aspect for irrigation demand forecasting at farm to catchment scale. Many models have been used to measure the ET rate, either empirical or functional. The major disadvantage of this approach is that most methods generate only point values, resulting in estimates that are not representative of large areas. These methods are based on crop factors under ideal conditions and cannot therefore represent actual crop ET. Satellite remote sensing is a powerful mean to estimate ET over various spatial and temporal scales. For improved irrigation system management and operation, a holistic approach of integrating remote sensing derived ET from SAM-ET (spatial algorithm for mapping ET) algorithm, for Australian agro-ecosystem, with forecasted meteorological data and field application loss functions for major crops were used to forecast actual water demand in Coleambally Irrigation Area (CIA), New South Wales, Australia. It covers approximately 79,000 ha of intensive irrigation and comprise of number of secondary and tertiary canals. In order to capture the spatial variability, CIA has been divided into 22 nodes based on direction of flow and connectivity. All hydrological data of inflow (i

  14. Uncertainty versus computer response time

    SciTech Connect

    Rowe, W.D. |

    1994-12-31

    Interactive on-line presentation of risk analysis results with immediate ``what if`` capability is now possible with available microcomputer technology. This can provide an effective means off presenting the risk results, the decision possibilities, and the underlying assumptions to decision makers, stakeholders, and the public. However, the limitation of computer calculational power on microcomputers requires a trade-off between the precision of the analysis and the computing and display response time. Fortunately, the uncertainties in the risk analysis are usually so large that extreme precision is often unwarranted. Therefore, risk analyses used for this purpose must include trade-offs between precision and processing time, and uncertainties introduced must be put into perspective.

  15. Assessing daily actual evapotranspiration through energy balance: an experiment to evaluate the selfpreservation hypothesis with acquisition time

    NASA Astrophysics Data System (ADS)

    Maltese, A.; Capodici, F.; Ciraolo, G.; La Loggia, G.; Rallo, G.

    2013-10-01

    An operational use of the actual evapotranspiration estimates requires the integration from instantaneous to daily values. This can commonly be achieved under the hypothesis of daytime self-preservation of the evaporative fraction. In this study, it has been evaluated the effect of this assumption on the assessment of daily evapotranspiration from proximity sensing images acquired at hourly intervals over a homogeneous olive groove. Results have been validated by comparison with observations made by a micrometeorological (EC-flux tower) and an eco-physiological (sap flux) sensor. SEBAL model has been applied to thermal and multispectral images acquired during a clear day on August 2009 trough a FLIR A320G thermal camera and a Tetracam MCA II multispectral camera, installed on a tethered helium balloon. Thermal and multispectral images were characterized by very high spatial resolution. This experiment aims to analyze two effects: 1) the consistency of the self-preservation hypothesis for daily estimates of the actual evapotranspiration from hourly assessments at different times of the day; 2) the effects of the spatial resolution on the performances of the energy balance model. To evaluate the effects of the spatial resolution, semi-hourly observations made by a flux tower and sap-flow measures were compared to the evapotranspiration estimates performed using downscaled images at resolutions close to canopy sizes (2, 5 and 10 m). Results show that the best estimates are obtained with a spatial resolution comparable to the average size of the canopy with images taken approximately at 10 UTC.

  16. 28 CFR 542.18 - Response time.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Response time. 542.18 Section 542.18... REMEDY Administrative Remedy Program § 542.18 Response time. If accepted, a Request or Appeal is... later than the third calendar day after filing. If the time period for response to a Request or...

  17. 28 CFR 542.18 - Response time.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Response time. 542.18 Section 542.18... REMEDY Administrative Remedy Program § 542.18 Response time. If accepted, a Request or Appeal is... later than the third calendar day after filing. If the time period for response to a Request or...

  18. 28 CFR 542.18 - Response time.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Response time. 542.18 Section 542.18... REMEDY Administrative Remedy Program § 542.18 Response time. If accepted, a Request or Appeal is... later than the third calendar day after filing. If the time period for response to a Request or...

  19. 28 CFR 542.18 - Response time.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Response time. 542.18 Section 542.18... REMEDY Administrative Remedy Program § 542.18 Response time. If accepted, a Request or Appeal is... later than the third calendar day after filing. If the time period for response to a Request or...

  20. A Measurement Model for Likert Responses that Incorporates Response Time

    ERIC Educational Resources Information Center

    Ferrando, Pere J.; Lorenzo-Seva, Urbano

    2007-01-01

    This article describes a model for response times that is proposed as a supplement to the usual factor-analytic model for responses to graded or more continuous typical-response items. The use of the proposed model together with the factor model provides additional information about the respondent and can potentially increase the accuracy of the…

  1. 28 CFR 542.18 - Response time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Response time. 542.18 Section 542.18 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT ADMINISTRATIVE REMEDY Administrative Remedy Program § 542.18 Response time. If accepted, a Request or Appeal...

  2. Actual timing of neodymium isotopic variations recorded by Fe-Mn crusts in the western North Atlantic

    USGS Publications Warehouse

    Burton, K.W.; Lee, D.-C.; Christensen, J.N.; Halliday, A.N.; Hein, J.R.

    1999-01-01

    Hydrogenetic ferromanganese (Fe-Mn) crusts from the western North Atlantic record variations in the Nd and Pb isotopic composition of Cenozoic deep water preserved during their growth. The timing and cause of the most striking change have been the subject of debate. Some have proposed that the shift took place after 4 Ma in response to the closure of the Panama gateway. Others have argued that the major change in isotope composition occurred as early as 8 Ma. This study presents high-resolution Nd isotope records for crusts previously dated using 10Be/9Be chronology. These data confirm that the shifts in Nd occurred after 4 Ma, consistent with a likely relationship with the closure of the Central American Isthmus and intensification of Northern Hemisphere Glaciation, and in accordance with changes seen in other physical and chemical records. These results illustrate the need for both a robust chronological framework and high-resolution records before a reliable paleoceanographic interpretation can be made of the variations recorded by Fe-Mn crusts.

  3. Silicon Timing Response to Particles and Light

    SciTech Connect

    Ronzhin, Anatoly; Spiropulu, Maria

    2015-01-01

    It is observed growing interest to fast timing detectors in high energy physics, related, for example, with collider luminosity increase (LHC) [1]. The options of CMS [2] calorimeter upgrade based on silicon detectors renewed interest to the timing study of this type of detectors. The article is devoted to study of silicon timing response to particles and light.

  4. Cognitive Reflection, Decision Biases, and Response Times

    PubMed Central

    Alós-Ferrer, Carlos; Garagnani, Michele; Hügelschäfer, Sabine

    2016-01-01

    We present novel evidence on response times and personality traits in standard questions from the decision-making literature where responses are relatively slow (medians around half a minute or above). To this end, we measured response times in a number of incentivized, framed items (decisions from description) including the Cognitive Reflection Test, two additional questions following the same logic, and a number of classic questions used to study decision biases in probability judgments (base-rate neglect, the conjunction fallacy, and the ratio bias). All questions create a conflict between an intuitive process and more deliberative thinking. For each item, we then created a non-conflict version by either making the intuitive impulse correct (resulting in an alignment question), shutting it down (creating a neutral question), or making it dominant (creating a heuristic question). For CRT questions, the differences in response times are as predicted by dual-process theories, with alignment and heuristic variants leading to faster responses and neutral questions to slower responses than the original, conflict questions. For decision biases (where responses are slower), evidence is mixed. To explore the possible influence of personality factors on both choices and response times, we used standard personality scales including the Rational-Experiential Inventory and the Big Five, and used them as controls in regression analysis. PMID:27713710

  5. Response time for multilayered platinum resistance thermometers

    NASA Technical Reports Server (NTRS)

    Pandey, D. K.; Ash, R. L.

    1985-01-01

    Response time constants for several multilayered temperature transducers were determined numerically by using Martin Marietta's MITAS software package which is available at NASA Langley Research Center. Present results were found in close agreement with the solutions reported in the literature, thus, the capability of MITAS was justified. On the basis of experiences gained, the MITAS is recommended for use in predicting the response time constants of sensors by an in-situ technique.

  6. The Value of Response Times in Item Response Modeling

    ERIC Educational Resources Information Center

    Molenaar, Dylan

    2015-01-01

    A new and very interesting approach to the analysis of responses and response times is proposed by Goldhammer (this issue). In his approach, differences in the speed-ability compromise within respondents are considered to confound the differences in ability between respondents. These confounding effects of speed on the inferences about ability can…

  7. A Ballistic Model of Choice Response Time

    ERIC Educational Resources Information Center

    Brown, Scott; Heathcote, Andrew

    2005-01-01

    Almost all models of response time (RT) use a stochastic accumulation process. To account for the benchmark RT phenomena, researchers have found it necessary to include between-trial variability in the starting point and/or the rate of accumulation, both in linear (R. Ratcliff & J. N. Rouder, 1998) and nonlinear (M. Usher & J. L. McClelland, 2001)…

  8. Perception Versus Actual Performance in Timely Tissue Plasminogen Activation Administration in the Management of Acute Ischemic Stroke

    PubMed Central

    Lin, Cheryl B; Cox, Margueritte; Olson, DaiWai M; Britz, Gavin W; Constable, Mark; Fonarow, Gregg C; Schwamm, Lee; Peterson, Eric D; Shah, Bimal R

    2015-01-01

    Background Timely thrombolytic therapy can improve stroke outcomes. Nevertheless, the ability of US hospitals to meet guidelines for intravenous tissue plasminogen activator (tPA) remains suboptimal. What is unclear is whether hospitals accurately perceive their rate of tPA “door-to-needle” (DTN) time within 60 minutes and how DTN rates compare across different hospitals. Methods and Results DTN performance was defined by the percentage of treated patients who received tPA within 60 minutes of arrival. Telephone surveys were obtained from staff at 141 Get With The Guidelines hospitals, representing top, middle, and lowDTN performance. Less than one-third (29.1%) of staff accurately identified their DTN performance. Among middle- and low-performing hospitals (n=92), 56 sites (60.9%) overestimated their performance; 42% of middle performers and 85% of low performers overestimated their performance. Sites that overestimated tended to have lower annual volumes of tPA administration (median 8.4 patients [25th to 75th percentile 5.9 to 11.8] versus 10.2 patients [25th to 75th percentile 8.2 to 17.3], P=0.047), smaller percentages of eligible patients receiving tPA (84.7% versus 89.8%, P=0.008), and smaller percentages of DTN ≤60 minutes among treated patients (10.6% versus 16.6%, P=0.002). Conclusions Hospitals often overestimate their ability to deliver timely tPA to treated patients. Our findings indicate the need to routinely provide comparative provider performance rates as a key step to improving the quality of acute stroke care. PMID:26201547

  9. Form and Actuality

    NASA Astrophysics Data System (ADS)

    Bitbol, Michel

    A basic choice underlies physics. It consists of banishing actual situations from theoretical descriptions, in order to reach a universal formal construct. Actualities are then thought of as mere local appearances of a transcendent reality supposedly described by the formal construct. Despite its impressive success, this method has left major loopholes in the foundations of science. In this paper, I document two of these loopholes. One is the problem of time asymmetry in statistical thermodynamics, and the other is the measurement problem of quantum mechanics. Then, adopting a broader philosophical standpoint, I try to turn the whole picture upside down. Here, full priority is given to actuality (construed as a mode of the immanent reality self-reflectively being itself) over formal constructs. The characteristic aporias of this variety of "Copernican revolution" are discussed.

  10. Patterns of Response Times and Response Choices to Science Questions: The Influence of Relative Processing Time

    ERIC Educational Resources Information Center

    Heckler, Andrew F.; Scaife, Thomas M.

    2015-01-01

    We report on five experiments investigating response choices and response times to simple science questions that evoke student "misconceptions," and we construct a simple model to explain the patterns of response choices. Physics students were asked to compare a physical quantity represented by the slope, such as speed, on simple physics…

  11. Method and apparatus for measuring response time

    DOEpatents

    Johanson, E.W.; August, C.

    1983-08-11

    A method of measuring the response time of an electrical instrument which generates an output signal in response to the application of a specified input, wherein the output signal varies as a function of time and when subjected to a step input approaches a steady-state value, comprises the steps of: (a) applying a step input of predetermined value to the electrical instrument to generate an output signal; (b) simultaneously starting a timer; (c) comparing the output signal to a reference signal to generate a stop signal when the output signal is substantially equal to the reference signal, the reference signal being a specified percentage of the steady-state value of the output signal corresponding to the predetermined value of the step input; and (d) applying the stop signal when generated to stop the timer.

  12. Method and apparatus for measuring response time

    DOEpatents

    Johanson, Edward W.; August, Charles

    1985-01-01

    A method of measuring the response time of an electrical instrument which generates an output signal in response to the application of a specified input, wherein the output signal varies as a function of time and when subjected to a step input approaches a steady-state value, comprises the steps of: (a) applying a step input of predetermined value to the electrical instrument to generate an output signal; (b) simultaneously starting a timer; (c) comparing the output signal to a reference signal to generate a stop signal when the output signal is substantially equal to the reference signal, the reference signal being a specified percentage of the steady-state value of the output signal corresponding to the predetermined value of the step input; and (d) applying the stop signal when generated to stop the timer.

  13. Binocular summation and peripheral visual response time

    NASA Technical Reports Server (NTRS)

    Gilliland, K.; Haines, R. F.

    1975-01-01

    Six males were administered a peripheral visual response time test to the onset of brief small stimuli imaged in 10-deg arc separation intervals across the dark adapted horizontal retinal meridian under both binocular and monocular viewing conditions. This was done in an attempt to verify the existence of peripheral binocular summation using a response time measure. The results indicated that from 50-deg arc right to 50-deg arc left of the line of sight binocular summation is a reasonable explanation for the significantly faster binocular data. The stimulus position by viewing eye interaction was also significant. A discussion of these and other analyses is presented along with a review of related literature.

  14. An Integer Batch Scheduling Model for a Single Machine with Simultaneous Learning and Deterioration Effects to Minimize Total Actual Flow Time

    NASA Astrophysics Data System (ADS)

    Yusriski, R.; Sukoyo; Samadhi, T. M. A. A.; Halim, A. H.

    2016-02-01

    In the manufacturing industry, several identical parts can be processed in batches, and setup time is needed between two consecutive batches. Since the processing times of batches are not always fixed during a scheduling period due to learning and deterioration effects, this research deals with batch scheduling problems with simultaneous learning and deterioration effects. The objective is to minimize total actual flow time, defined as a time interval between the arrival of all parts at the shop and their common due date. The decision variables are the number of batches, integer batch sizes, and the sequence of the resulting batches. This research proposes a heuristic algorithm based on the Lagrange Relaxation. The effectiveness of the proposed algorithm is determined by comparing the resulting solutions of the algorithm to the respective optimal solution obtained from the enumeration method. Numerical experience results show that the average of difference among the solutions is 0.05%.

  15. Response time correlations for platinum resistance thermometers

    NASA Technical Reports Server (NTRS)

    Pandey, D. K.; Ash, R. L.; Dillon-Townes, L. A.

    1985-01-01

    The 'plunge method' recommended by ASTM has been used to determine the time constant of 100-ohm platinum resistance thermometers (PRT) considered for use in the National Transonic Facility. It is shown that the response time of ventilated PRT can be correlated with the reciprocal of the heat transfer coefficient in a given field. Universal correlations are established for the 100- and 1000-ohm PRT with uncertainties of 20 and 30 percent, respectively. The correlations are found to be consistent with the uncertainty involved in heat transfer correlations available in the literature and are recommended for use in flowing liquids and gases.

  16. Problem gamblers are hyposensitive to wins: an analysis of skin conductance responses during actual gambling on electronic gaming machines.

    PubMed

    Lole, Lisa; Gonsalvez, Craig J; Barry, Robert J; Blaszczynski, Alex

    2014-06-01

    Physiological arousal is purportedly a key determinant in the development and maintenance of gambling behaviors, with problem gambling conceptualized in terms of abnormal autonomic responses. Theoretical conceptualizations of problem gambling are discordant regarding the nature of deficit in this disorder; some accounts posit that problem gamblers are hypersensitive to reward, and others that they are hyposensitive to reward and/or punishment. Previous research examining phasic electrodermal responses in gamblers has been limited to laboratory settings, and reactions to real gaming situations need to be examined. Skin conductance responses (SCRs) to losses, wins, and losses disguised as wins (LDWs) were recorded from 15 problem gamblers (PGs) and 15 nonproblem gamblers (NPGs) while they wagered their own money during electronic gaming machine play. PGs demonstrated significantly reduced SCRs to reward. SCRs to losses and LDWs did not differ for either PGs or NPGs. This hyposensitivity to wins may reflect abnormalities in incentive processing, and may represent a potential biological marker for problem gambling. PMID:24588340

  17. Time-dependent onshore tsunami response

    USGS Publications Warehouse

    Apotsos, Alex; Gelfenbaum, Guy R.; Jaffe, Bruce E.

    2012-01-01

    While bulk measures of the onshore impact of a tsunami, including the maximum run-up elevation and inundation distance, are important for hazard planning, the temporal evolution of the onshore flow dynamics likely controls the extent of the onshore destruction and the erosion and deposition of sediment that occurs. However, the time-varying dynamics of actual tsunamis are even more difficult to measure in situ than the bulk parameters. Here, a numerical model based on the non-linear shallow water equations is used to examine the effects variations in the wave characteristics, bed slope, and bottom roughness have on the temporal evolution of the onshore flow. Model results indicate that the onshore flow dynamics vary significantly over the parameter space examined. For example, the flow dynamics over steep, smooth morphologies tend to be temporally symmetric, with similar magnitude velocities generated during the run-up and run-down phases of inundation. Conversely, on shallow, rough onshore topographies the flow dynamics tend to be temporally skewed toward the run-down phase of inundation, with the magnitude of the flow velocities during run-up and run-down being significantly different. Furthermore, for near-breaking tsunami waves inundating over steep topography, the flow velocity tends to accelerate almost instantaneously to a maximum and then decrease monotonically. Conversely, when very long waves inundate over shallow topography, the flow accelerates more slowly and can remain steady for a period of time before beginning to decelerate. These results indicate that a single set of assumptions concerning the onshore flow dynamics cannot be applied to all tsunamis, and site specific analyses may be required.

  18. Comparison of Clinician Judgments and Measurements of Swallow Response Time: A Preliminary Report

    ERIC Educational Resources Information Center

    Karnell, Michael P.; Rogus, Nicole M.

    2005-01-01

    Practicing clinicians frequently offer judgments about aspects of swallowing physiology rather than performing actual measurements. Little is known about the accuracy of those judgments. The purpose of this preliminary study was to explore agreement of clinicians' judgments of pharyngeal swallow response time (PSRT) with temporal measurements of…

  19. Patterns of response times and response choices to science questions: the influence of relative processing time.

    PubMed

    Heckler, Andrew F; Scaife, Thomas M

    2015-04-01

    We report on five experiments investigating response choices and response times to simple science questions that evoke student "misconceptions," and we construct a simple model to explain the patterns of response choices. Physics students were asked to compare a physical quantity represented by the slope, such as speed, on simple physics graphs. We found that response times of incorrect answers, resulting from comparing heights, were faster than response times of correct answers comparing slopes. This result alone might be explained by the fact that height was typically processed faster than slope for this kind of task, which we confirmed in a separate experiment. However, we hypothesize that the difference in response time is an indicator of the cause (rather than the result) of the response choice. To support this, we found that imposing a 3-s delay in responding increased the number of students comparing slopes (answering correctly) on the task. Additionally a significant proportion of students recognized the correct written rule (compare slope), but on the graph task they incorrectly compared heights. Finally, training either with repetitive examples or providing a general rule both improved scores, but only repetitive examples had a large effect on response times, thus providing evidence of dual paths or processes to a solution. Considering models of heuristics, information accumulation models, and models relevant to the Stroop effect, we construct a simple relative processing time model that could be viewed as a kind of fluency heuristic. The results suggest that misconception-like patterns of answers to some science questions commonly found on tests may be explained in part by automatic processes that involve the relative processing time of considered dimensions and a priority to answer quickly. PMID:25230833

  20. Residential Real-time Price Response Simulation

    SciTech Connect

    Widergren, Steven E.; Subbarao, Krishnappa; Chassin, David P.; Fuller, Jason C.; Pratt, Robert G.

    2011-10-10

    The electric industry is gaining experience with innovative price responsive demand pilots and limited roll-outs to customers. One of these pilots is investigating real-time pricing signals to engage end-use systems and local distributed generation and storage in a distributed optimization process. Attractive aspects about the approach include strong scalability characteristics, simplified interfaces between automation devices, and the adaptability to integrate a wide variety of devices and systems. Experience in this nascent field is revealing a rich array of for engineering decisions and the application of complexity theory. To test the decisions, computer simulations are used to reveal insights about design, demand elasticity, and the limits of response (including consumer fatigue). Agent-based approaches lend themselves well in the simulation to modeling the participation and interaction of each piece of equipment on a distribution feeder. This paper discusses rate design and simulation experiences at the distribution feeder level where consumers and their HVAC systems and water heaters on a feeder receive real-time pricing signals.

  1. A mixture hierarchical model for response times and response accuracy.

    PubMed

    Wang, Chun; Xu, Gongjun

    2015-11-01

    In real testing, examinees may manifest different types of test-taking behaviours. In this paper we focus on two types that appear to be among the more frequently occurring behaviours – solution behaviour and rapid guessing behaviour. Rapid guessing usually happens in high-stakes tests when there is insufficient time, and in low-stakes tests when there is lack of effort. These two qualitatively different test-taking behaviours, if ignored, will lead to violation of the local independence assumption and, as a result, yield biased item/person parameter estimation. We propose a mixture hierarchical model to account for differences among item responses and response time patterns arising from these two behaviours. The model is also able to identify the specific behaviour an examinee engages in when answering an item. A Monte Carlo expectation maximization algorithm is proposed for model calibration. A simulation study shows that the new model yields more accurate item and person parameter estimates than a non-mixture model when the data indeed come from two types of behaviour. The model also fits real, high-stakes test data better than a non-mixture model, and therefore the new model can better identify the underlying test-taking behaviour an examinee engages in on a certain item. PMID:25873487

  2. Change in response time of stroke patients and controls during rehabilitation.

    PubMed

    Korner-Bitensky, N; Mayo, N E; Kaizer, F

    1990-02-01

    In this study we investigated motor response times of stroke patients at admission to a rehabilitation hospital and again after 6 wk of hospitalization. A prospective comparative study was carried out on 164 stroke patients; 48 hospitalized patients served as controls. Mean motor response times to visual stimuli presented in the left and right visual fields and to centrally presented stimuli were studied. The principle finding was that stroke patients improved significantly in their response times from initial to final evaluation. While at initial assessment they performed significantly more slowly than controls, by final assessment the response times of the two groups did not differ. Visual hemineglect influenced change in response time differentially depending on side of lesion: right hemisphere lesion patients with neglect improved, whereas left hemisphere lesion patients with neglect actually deteriorated. The presence of depression influenced right hemisphere lesion patients' response times and change in response times but it did not have any influence for left hemisphere lesion patients. The findings that response time generally improved during rehabilitation has important implications for the treatment of individuals with brain injury. It will be important to identify therapeutic practices which will be effective in the remediation of response time for all patients. Ultimately the goal of intervening in slow response time is to improve performance of functional activities which are influenced by an individual's ability to respond to visual stimuli.

  3. A Flexible Latent Trait Model for Response Times in Tests

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jorg-Tobias

    2012-01-01

    Latent trait models for response times in tests have become popular recently. One challenge for response time modeling is the fact that the distribution of response times can differ considerably even in similar tests. In order to reduce the need for tailor-made models, a model is proposed that unifies two popular approaches to response time…

  4. Improving OCD time to solution using Signal Response Metrology

    NASA Astrophysics Data System (ADS)

    Fang, Fang; Zhang, Xiaoxiao; Vaid, Alok; Pandev, Stilian; Sanko, Dimitry; Ramanathan, Vidya; Venkataraman, Kartik; Haupt, Ronny

    2016-03-01

    In recent technology nodes, advanced process and novel integration scheme have challenged the precision limits of conventional metrology; with critical dimensions (CD) of device reduce to sub-nanometer region. Optical metrology has proved its capability to precisely detect intricate details on the complex structures, however, conventional RCWA-based (rigorous coupled wave analysis) scatterometry has the limitations of long time-to-results and lack of flexibility to adapt to wide process variations. Signal Response Metrology (SRM) is a new metrology technique targeted to alleviate the consumption of engineering and computation resources by eliminating geometric/dispersion modeling and spectral simulation from the workflow. This is achieved by directly correlating the spectra acquired from a set of wafers with known process variations encoded. In SPIE 2015, we presented the results of SRM application in lithography metrology and control [1], accomplished the mission of setting up a new measurement recipe of focus/dose monitoring in hours. This work will demonstrate our recent field exploration of SRM implementation in 20nm technology and beyond, including focus metrology for scanner control; post etch geometric profile measurement, and actual device profile metrology.

  5. 39 CFR 3004.45 - Extension of response time limit.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ACT § 3004.45 Extension of response time limit. (a) The Commission may extend the time limit for a response at the request stage and at the appeal stage up to 10 working days due to unusual circumstances...

  6. 39 CFR 3004.45 - Extension of response time limit.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ACT § 3004.45 Extension of response time limit. (a) The Commission may extend the time limit for a response at the request stage and at the appeal stage up to 10 working days due to unusual circumstances...

  7. 40 CFR 1066.245 - Response time verification.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... dynamometer's automated process to verify response time. Perform this test at two different inertia settings... observed settling response time must be less than 100 milliseconds for each inertia setting. ER15SE11.085...

  8. Analyzing Response Times in Tests with Rank Correlation Approaches

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jorg-Tobias

    2013-01-01

    It is common practice to log-transform response times before analyzing them with standard factor analytical methods. However, sometimes the log-transformation is not capable of linearizing the relation between the response times and the latent traits. Therefore, a more general approach to response time analysis is proposed in the current…

  9. 48 CFR 205.203 - Publicizing and response time.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Publicizing and response time. 205.203 Section 205.203 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS... Contract Actions 205.203 Publicizing and response time. (b) Allow at least 45 days response time...

  10. 48 CFR 205.203 - Publicizing and response time.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Publicizing and response time. 205.203 Section 205.203 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS... Contract Actions 205.203 Publicizing and response time. (b) Allow at least 45 days response time...

  11. Improving Adaptive Learning Technology through the Use of Response Times

    ERIC Educational Resources Information Center

    Mettler, Everett; Massey, Christine M.; Kellman, Philip J.

    2011-01-01

    Adaptive learning techniques have typically scheduled practice using learners' accuracy and item presentation history. We describe an adaptive learning system (Adaptive Response Time Based Sequencing--ARTS) that uses both accuracy and response time (RT) as direct inputs into sequencing. Response times are used to assess learning strength and…

  12. System measures response time of photomultiplier tubes

    NASA Technical Reports Server (NTRS)

    Lauver, M. R.

    1968-01-01

    Calibration system enables precise determination of rise time of photosensitive detectors. To perform a calibration, the time-voltage curve of the excitation voltage for a light source is compared with the time-voltage curve of the voltage output from a photosensitive detector which is responding to the light.

  13. Design of responsive polymer surfaces with ultrafast response time

    NASA Astrophysics Data System (ADS)

    Genzer, Jan; Ozcam, Evren; Willoughby, Julie

    2009-03-01

    Responsive surfaces with tailorable surface-reconstruction kinetics and switching hysteresis were prepared from poly(vinylmethylsiloxane) (PVMS) networks modified with thiol alkanes to provide hydrophobic or hydrophilic surface properties. The cooperative effects of polymer mobility, arising from the high flexibility of the siloxane backbone, and the enthalpic interactions between the contacting medium and the PVMS functionalized surface control the degree of responsiveness. Exposing the modified-elastomer surfaces to water resulted in rearrangement of the hydrophilic alkanes at the surface. The kinetics of reconstruction and reversibility were established by measuring the surface wettability via dynamic contact angle. By controlling the formation of semi-crystalline regions in our substrates we demonstrate either ``sluggish'' kinetics and eventual surface ``freezing'' and stability or stimuli-responsive substrates with a magnitude of change and repeated reversibility unparallel to most polymeric surfaces.

  14. Dispersion of Response Times Reveals Cognitive Dynamics

    ERIC Educational Resources Information Center

    Holden, John G.; Van Orden, Guy C.; Turvey, Michael T.

    2009-01-01

    Trial-to-trial variation in word-pronunciation times exhibits 1/f scaling. One explanation is that human performances are consequent on multiplicative interactions among interdependent processes-interaction dominant dynamics. This article describes simulated distributions of pronunciation times in a further test for multiplicative interactions and…

  15. Response modalities and time-sharing performance

    NASA Technical Reports Server (NTRS)

    Vidulich, Michael A.

    1986-01-01

    An experiment performed to investigate the role of resource competition and asymmetric transfer in dual-task performance is described. It is shown that there is an advantage to mixed manual/speech response modality configurations that cannot be accounted for by asymmetric transfer. The present results support the multiple resources approach to the application of speech technology. Once speech recognition achieves an acceptable level of operational reliability, speech controls can be used to reduce resource competition and improve performance in multitask environments.

  16. Temperate grass response to timing of grazing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grazing management has a significant impact on pasture growth. We determined how timing of grazing influences grass productivity, yield distribution, and persistence. Meadow fescue [Schedonorus pratensis (Huds.) P. Beauv.], orchardgrass (Dactylis glomerata L.), quackgrass [Elymus repens (L.) Gould...

  17. Modeling an Application's Theoretical Minimum and Average Transactional Response Times

    SciTech Connect

    Paiz, Mary Rose

    2015-04-01

    The theoretical minimum transactional response time of an application serves as a ba- sis for the expected response time. The lower threshold for the minimum response time represents the minimum amount of time that the application should take to complete a transaction. Knowing the lower threshold is beneficial in detecting anomalies that are re- sults of unsuccessful transactions. On the converse, when an application's response time falls above an upper threshold, there is likely an anomaly in the application that is causing unusual performance issues in the transaction. This report explains how the non-stationary Generalized Extreme Value distribution is used to estimate the lower threshold of an ap- plication's daily minimum transactional response time. It also explains how the seasonal Autoregressive Integrated Moving Average time series model is used to estimate the upper threshold for an application's average transactional response time.

  18. A Study of Bayesian Estimation and Comparison of Response Time Models in Item Response Theory

    ERIC Educational Resources Information Center

    Suh, Hongwook

    2010-01-01

    Response time has been regarded as an important source for investigating the relationship between human performance and response speed. It is important to examine the relationship between response time and item characteristics, especially in the perspective of the relationship between response time and various factors that affect examinee's…

  19. A Lognormal Model for Response Times on Test Items

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2006-01-01

    A lognormal model for the response times of a person on a set of test items is investigated. The model has a parameter structure analogous to the two-parameter logistic response models in item response theory, with a parameter for the speed of each person as well as parameters for the time intensity and discriminating power of each item. It is…

  20. Using Response Times for Item Selection in Adaptive Testing

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2008-01-01

    Response times on items can be used to improve item selection in adaptive testing provided that a probabilistic model for their distribution is available. In this research, the author used a hierarchical modeling framework with separate first-level models for the responses and response times and a second-level model for the distribution of the…

  1. Quantification and classification of neuronal responses in kernel-smoothed peristimulus time histograms.

    PubMed

    Hill, Michael R H; Fried, Itzhak; Koch, Christof

    2015-02-15

    Peristimulus time histograms are a widespread form of visualizing neuronal responses. Kernel convolution methods transform these histograms into a smooth, continuous probability density function. This provides an improved estimate of a neuron's actual response envelope. We here develop a classifier, called the h-coefficient, to determine whether time-locked fluctuations in the firing rate of a neuron should be classified as a response or as random noise. Unlike previous approaches, the h-coefficient takes advantage of the more precise response envelope estimation provided by the kernel convolution method. The h-coefficient quantizes the smoothed response envelope and calculates the probability of a response of a given shape to occur by chance. We tested the efficacy of the h-coefficient in a large data set of Monte Carlo simulated smoothed peristimulus time histograms with varying response amplitudes, response durations, trial numbers, and baseline firing rates. Across all these conditions, the h-coefficient significantly outperformed more classical classifiers, with a mean false alarm rate of 0.004 and a mean hit rate of 0.494. We also tested the h-coefficient's performance in a set of neuronal responses recorded in humans. The algorithm behind the h-coefficient provides various opportunities for further adaptation and the flexibility to target specific parameters in a given data set. Our findings confirm that the h-coefficient can provide a conservative and powerful tool for the analysis of peristimulus time histograms with great potential for future development. PMID:25475352

  2. Response time characterization of fast responding pressure-sensitive paint

    NASA Astrophysics Data System (ADS)

    Ozaki, Tatsuya; Ishikawa, Hitoshi; Sakaue, Hirotaka

    2010-11-01

    Response time characterization of a fast responding pressure-sensitive paint (PSP) is important information in measuring an unsteady flow field. PSP is an optical pressure sensor. The luminescent image from the PSP is related to a pressure map. In the previous works, a time delay from a step change of pressure is generally used to characterize the response time. The thickness of the PSP as well as the PSP binding material greatly influences the response time. Because the temperature influences the diffusion or permeation of a PSP binder, it is also an important parameter to influence the response time. We build a shock tube to create a step change of pressure for response time characterization. This can control the temperature of the PSP. We discuss the PSP response times related to the temperature of the binder as well as the binding materials.

  3. On the response time of plasmonic terahertz detectors

    NASA Astrophysics Data System (ADS)

    Muravev, V. M.; Solov'ev, V. V.; Fortunatov, A. A.; Tsydynzhapov, G. E.; Kukushkin, I. V.

    2016-06-01

    The response time of a plasmonic terahertz detector is investigated using two independent experimental techniques relying on time-resolved and heterodyne measurements, respectively. Both methods demonstrate that the detector response time does not exceed 110 ps. The results obtained suggest that the designed terahertz detector can be used as a component of high-speed telecommunication systems of a new generation.

  4. Latent Response Times and Cognitive Processing on the FMCE

    NASA Astrophysics Data System (ADS)

    Bonham, Scott

    2008-10-01

    Latent response time analysis of students on an electronic version of the Force and Motion Conceptual Evaluation (FMCE) provides information on student reading patterns and the role of mental models in student reasoning. Regression analysis looked at the dependence of response times on characteristics of questions, such as amount of text and inclusion of graphs. Results indicate that students generally read through the question text and instructions when first presented, but do not systematically read through answer choices and graphs. Comparison of average response times between pre- and post-instructional assessment found a drop in response times when students used Newtonian ideas but no change for responses using the main alternative concept. The average response time for students who answered using a mix of Newtonian and alternative concepts was not different from those using primarily one or the other; questions rarely activated both concepts at the same time.

  5. A Comparison of Response Rate, Response Time, and Costs of Mail and Electronic Surveys.

    ERIC Educational Resources Information Center

    Shannon, David M.; Bradshaw, Carol C.

    2002-01-01

    Compared response rates, response time, and costs of mail and electronic surveys using a sample of 377 college faculty members. Mail surveys yielded a higher response rate and a lower rate of undeliverable surveys, but response time was longer and costs were higher than for electronic surveys. (SLD)

  6. Hierarchical Diffusion Models for Two-Choice Response Times

    ERIC Educational Resources Information Center

    Vandekerckhove, Joachim; Tuerlinckx, Francis; Lee, Michael D.

    2011-01-01

    Two-choice response times are a common type of data, and much research has been devoted to the development of process models for such data. However, the practical application of these models is notoriously complicated, and flexible methods are largely nonexistent. We combine a popular model for choice response times--the Wiener diffusion…

  7. 10 CFR 1303.107 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Timing of responses to requests. 1303.107 Section 1303.107 Energy NUCLEAR WASTE TECHNICAL REVIEW BOARD PUBLIC INFORMATION AND REQUESTS § 1303.107 Timing of responses to requests. (a) General. The Board shall normally respond to requests in the order of...

  8. 40 CFR 1601.24 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Timing of responses to requests. 1601... Disclosing Records § 1601.24 Timing of responses to requests. (a) In general. The CSB ordinarily shall... an imminent threat to the life or physical safety of an individual; (ii) An urgency to inform...

  9. 10 CFR 1303.107 - Timing of responses to requests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Timing of responses to requests. 1303.107 Section 1303.107 Energy NUCLEAR WASTE TECHNICAL REVIEW BOARD PUBLIC INFORMATION AND REQUESTS § 1303.107 Timing of responses to requests. (a) General. The Board shall normally respond to requests in the order of...

  10. 10 CFR 1303.107 - Timing of responses to requests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Timing of responses to requests. 1303.107 Section 1303.107 Energy NUCLEAR WASTE TECHNICAL REVIEW BOARD PUBLIC INFORMATION AND REQUESTS § 1303.107 Timing of responses to requests. (a) General. The Board shall normally respond to requests in the order of...

  11. 10 CFR 1303.107 - Timing of responses to requests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Timing of responses to requests. 1303.107 Section 1303.107 Energy NUCLEAR WASTE TECHNICAL REVIEW BOARD PUBLIC INFORMATION AND REQUESTS § 1303.107 Timing of responses to requests. (a) General. The Board shall normally respond to requests in the order of...

  12. 10 CFR 1303.107 - Timing of responses to requests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Timing of responses to requests. 1303.107 Section 1303.107 Energy NUCLEAR WASTE TECHNICAL REVIEW BOARD PUBLIC INFORMATION AND REQUESTS § 1303.107 Timing of responses to requests. (a) General. The Board shall normally respond to requests in the order of...

  13. Testing for Aberrant Behavior in Response Time Modeling

    ERIC Educational Resources Information Center

    Marianti, Sukaesi; Fox, Jean-Paul; Avetisyan, Marianna; Veldkamp, Bernard P.; Tijmstra, Jesper

    2014-01-01

    Many standardized tests are now administered via computer rather than paper-and-pencil format. In a computer-based testing environment, it is possible to record not only the test taker's response to each question (item) but also the amount of time spent by the test taker in considering and answering each item. Response times (RTs) provide…

  14. 48 CFR 5.203 - Publicizing and response time.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... GPE (see 5.201). All publicizing and response times are calculated based on the date of publication. The publication date is the date the notice appears on the GPE. The notice must be published at least... day response time from the date of publication of a proper notice of intent to contract for...

  15. 48 CFR 5.203 - Publicizing and response time.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... GPE (see 5.201). All publicizing and response times are calculated based on the date of publication. The publication date is the date the notice appears on the GPE. The notice must be published at least... day response time from the date of publication of a proper notice of intent to contract for...

  16. 6 CFR 5.5 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Timing of responses to requests. 5.5 Section 5.5 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY DISCLOSURE OF RECORDS AND INFORMATION Freedom of Information Act § 5.5 Timing of responses to requests. (a) In general....

  17. Response Time Variations in an Online Search System.

    ERIC Educational Resources Information Center

    Cooper, Michael D.

    1983-01-01

    Explores response time variations in National Library of Medicine's ELHILL bibliographic search system and analyzes statistical significance of response time in terms of its variations by day of week, hour of day, particular bibliographic file being searched, command issued by user, number of users logged onto system. Ten references are cited.…

  18. 48 CFR 1505.203 - Publicizing and response time.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Publicizing and response time. 1505.203 Section 1505.203 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Synopses of Proposed Contract Actions 1505.203 Publicizing and response time. (a) The...

  19. Actual Knowledge under "Gebser v. Lago Vista": Evidence of the Court's Deliberate Indifference or an Appropriate Response for Finding Institutional Liability?

    ERIC Educational Resources Information Center

    Neiger, Jan Alan

    1999-01-01

    Reviews the history of Title IX and the various liability standards adopted by the federal courts. Provides a critical review of the "Gebser v. Lago Vista" decision and concludes that the Court's institutional liability standard is that actual knowledge is the most appropriate and legally sound standard of liability for teacher-to-student sexual…

  20. Improving the Average Response Time in Collective I/O

    SciTech Connect

    Jin, Chen; Sehrish, Saba; Liao, Wei-keng; Choudhary, Alok; Schuchardt, Karen L.

    2011-09-21

    In collective I/O, MPI processes exchange requests so that the rearranged requests can result in the shortest file system access time. Scheduling the exchange sequence determines the response time of participating processes. Existing implementations that simply follow the increasing order of file ofsets do not necessary produce the best performance. To minimize the average response time, we propose three scheduling algorithms that consider the number of processes per file stripe and the number of accesses per process. Our experimental results demonstrate improvements of up to 50% in the average response time using two synthetic benchmarks and a high-resolution climate application.

  1. Passenger comfort response times as a function of aircraft motion

    NASA Technical Reports Server (NTRS)

    Rinalducci, E. J.

    1975-01-01

    The relationship between a passenger's response time of changes in level of comfort experienced as a function of aircraft motion was examined. The aircraft used in this investigation was capable of providing a wide range of vertical and transverse accelerations by means of direct lift flap control surfaces and side force generator surfaces in addition to normal control surfaces. Response times to changes in comfort were recorded along with the passenger's rating of comfort on a five point scale. In addition, a number of aircraft motion variables including vertical and transverse accelerations were also recorded. Results indicate some relationship between human comfort response times to reaction time data.

  2. Computer Response Time Measurements of Mood, Fatigue and Symptom Scale Items: Implications for Scale Response Time Uses.

    ERIC Educational Resources Information Center

    Ryman, David H.; And Others

    1988-01-01

    Describes study conducted with U.S. Marine Corps enlisted personnel to measure response time to computer-administered questionnaire items, and to evaluate how measurement of response time might be useful in various research areas. Topics addressed include mood states; the occurrence of straight lining; and experimental effects of sleep loss and…

  3. An Item Response Theory Model for Incorporating Response Time Data in Binary Personality Items

    ERIC Educational Resources Information Center

    Ferrando, Pere J.; Lorenzo-Seva, Urbano

    2007-01-01

    This article describes a general item response theory model for personality items that allows the information provided by the item response times to be used to estimate the individual trait levels. The submodel describing the item response times is a modification of Thissen's log-linear model and is based on the distance-difficulty hypothesis in…

  4. Improving Item Response Theory Model Calibration by Considering Response Times in Psychological Tests

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jorg-Tobias

    2012-01-01

    Research findings indicate that response times in personality scales are related to the trait level according to the so-called speed-distance hypothesis. Against this background, Ferrando and Lorenzo-Seva proposed a latent trait model for the responses and response times in a test. The model consists of two components, a standard item response…

  5. Neural Basis of Adaptive Response Time Adjustment during Saccade Countermanding

    PubMed Central

    Pouget, Pierre; Logan, Gordon D.; Palmeri, Thomas J.; Boucher, Leanne; Paré, Martin; Schall, Jeffrey D.

    2011-01-01

    Humans and macaque monkeys adjust their response time adaptively in stop signal (countermanding) tasks, responding slower after stop-signal trials than after control trials with no stop signal. We investigated the neural mechanism underlying this adaptive response time adjustment in macaque monkeys performing a saccade countermanding task. Earlier research showed that movements are initiated when the random accumulation of presaccadic movement-related activity reaches a fixed threshold. We found that a systematic delay in response time after stop signal trials was accomplished not through a change of threshold, baseline, or accumulation rate, but instead through a change in the time when activity first began to accumulate. The neurons underlying movement initiation have been identified with mathematical accumulator models of response time performance. Therefore, this new result provides surprising new insights into the neural instantiation of stochastic accumulator models and the mechanisms through which executive control can be exerted. PMID:21880921

  6. Improved design provides faster response time in photomultiplier

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Dynamic Crossed-Field Electron Multiplying /DCFEM/ light demodulator avoids the normal response time limitations inherent in static field devices by using time varying crossed electric and static magnetic fields. This eliminates the transit time spread that affects electrons as they proceed along the secondary emission stages of the tube.

  7. Distinguishing Fast and Slow Processes in Accuracy - Response Time Data.

    PubMed

    Coomans, Frederik; Hofman, Abe; Brinkhuis, Matthieu; van der Maas, Han L J; Maris, Gunter

    2016-01-01

    We investigate the relation between speed and accuracy within problem solving in its simplest non-trivial form. We consider tests with only two items and code the item responses in two binary variables: one indicating the response accuracy, and one indicating the response speed. Despite being a very basic setup, it enables us to study item pairs stemming from a broad range of domains such as basic arithmetic, first language learning, intelligence-related problems, and chess, with large numbers of observations for every pair of problems under consideration. We carry out a survey over a large number of such item pairs and compare three types of psychometric accuracy-response time models present in the literature: two 'one-process' models, the first of which models accuracy and response time as conditionally independent and the second of which models accuracy and response time as conditionally dependent, and a 'two-process' model which models accuracy contingent on response time. We find that the data clearly violates the restrictions imposed by both one-process models and requires additional complexity which is parsimoniously provided by the two-process model. We supplement our survey with an analysis of the erroneous responses for an example item pair and demonstrate that there are very significant differences between the types of errors in fast and slow responses. PMID:27167518

  8. Diminished Response of Arctic Plants to Warming over Time

    PubMed Central

    Kremers, Kelseyann S.; Hollister, Robert D.; Oberbauer, Steven F.

    2015-01-01

    The goal of this study is to determine if the response of arctic plants to warming is consistent across species, locations and time. This study examined the impact of experimental warming and natural temperature variation on plants at Barrow and Atqasuk, Alaska beginning in 1994. We considered observations of plant performance collected from 1994–2000 “short-term” and those from 2007–2012 “long-term”. The plant traits reported are the number of inflorescences, inflorescence height, leaf length, and day of flower emergence. These traits can inform us about larger scale processes such as plant reproductive effort, plant growth, and plant phenology, and therefore provide valuable insight into community dynamics, carbon uptake, and trophic interactions. We categorized traits of all species monitored at each site into temperature response types. We then compared response types across traits, plant growth forms, sites, and over time to analyze the consistency of plant response to warming. Graminoids were the most responsive to warming and showed a positive response to temperature, while shrubs were generally the least responsive. Almost half (49%) of response types (across all traits, species, and sites combined) changed from short-term to long-term. The percent of plants responsive to warming decreased from 57% (short-term) to 46% (long-term). These results indicate that the response of plants to warming varies over time and has diminished overall in recent years. PMID:25767881

  9. Response-time testing for subsea controls in the Cadlao Field

    SciTech Connect

    Manuel, W.S.; Hall, J.E.

    1983-10-01

    This paper describes the response time properties of the direct hydraulic control system for the subsea Christmas trees installed in the Cadlao Field, offshore Philippines. Experimental testing simulated 29 different operating conditions to verify analytical predictions, to demonstrate the effectiveness of applying a common boost pressure to the spring chambers of the gate valve actuators, and to collect data for future applications. Actual data are presented and various relationships defined. With the use of boost, direct, closed hydraulic circuits with ganged functions offer a viable control method for distances up to 3 miles.

  10. Grade of Membership Response Time Model for Detecting Guessing Behaviors

    ERIC Educational Resources Information Center

    Pokropek, Artur

    2016-01-01

    A response model that is able to detect guessing behaviors and produce unbiased estimates in low-stake conditions using timing information is proposed. The model is a special case of the grade of membership model in which responses are modeled as partial members of a class that is affected by motivation and a class that responds only according to…

  11. A Mixture Rasch Model with Item Response Time Components

    ERIC Educational Resources Information Center

    Meyer, J. Patrick

    2010-01-01

    An examinee faced with a test item will engage in solution behavior or rapid-guessing behavior. These qualitatively different test-taking behaviors bias parameter estimates for item response models that do not control for such behavior. A mixture Rasch model with item response time components was proposed and evaluated through application to real…

  12. A Mechanism for Error Detection in Speeded Response Time Tasks

    ERIC Educational Resources Information Center

    Holroyd, Clay B.; Yeung, Nick; Coles, Michael G. H.; Cohen, Jonathan D.

    2005-01-01

    The concept of error detection plays a central role in theories of executive control. In this article, the authors present a mechanism that can rapidly detect errors in speeded response time tasks. This error monitor assigns values to the output of cognitive processes involved in stimulus categorization and response generation and detects errors…

  13. Response time to colored stimuli in the full visual field

    NASA Technical Reports Server (NTRS)

    Haines, R. F.; Dawson, L. M.; Galvan, T.; Reid, L. M.

    1975-01-01

    Peripheral visual response time was measured in seven dark adapted subjects to the onset of small (45' arc diam), brief (50 msec), colored (blue, yellow, green, red) and white stimuli imaged at 72 locations within their binocular field of view. The blue, yellow, and green stimuli were matched for brightness at about 2.6 sub log 10 units above their absolute light threshold, and they appeared at an unexpected time and location. These data were obtained to provide response time and no-response data for use in various design disciplines involving instrument panel layout. The results indicated that the retina possesses relatively concentric regions within each of which mean response time can be expected to be of approximately the same duration. These regions are centered near the fovea and extend farther horizontally than vertically. Mean foveal response time was fastest for yellow and slowest for blue. Three and one-half percent of the total 56,410 trials presented resulted in no-responses. Regardless of stimulus color, the lowest percentage of no-responses occurred within 30 deg arc from the fovea and the highest within 40 deg to 80 deg arc below the fovea.

  14. Peripheral visual response time and visual display layout

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1974-01-01

    Experiments were performed on a group of 42 subjects in a study of their peripheral visual response time to visual signals under positive acceleration, during prolonged bedrest, at passive 70 deg headup body lift, under exposures to high air temperatures and high luminance levels, and under normal stress-free laboratory conditions. Diagrams are plotted for mean response times to white, red, yellow, green, and blue stimuli under different conditions.

  15. On the actual variety of plate dynamical mechanisms and how mantle evolution affected them through time, from core formation to the Indian collision

    NASA Astrophysics Data System (ADS)

    Osmaston, Miles

    2010-05-01

    If horizontal plate motions were driven by thermal convection of the mantle, they would display the action of slow-to-change body forces. Yet rapid changes of spreading rate and direction, and ridge jumps, are well-documented for the past 130Ma. Also convection cannot readily cause rotations of a plate (e.g. Africa) about a pole within the plate or near it. And plate motions, especially that of India, scarcely fit a convective pattern. To address these problems we look first at mantle motivation at both ends of earth history, beginning with core formation. I then introduce 3 important properties of mantle materials, whose neglect by mantle modellers has surely impaired the value of their work, but whose recognition illuminates the present plate dynamical situation and provides the Earth with a heat engine that is not thermal convection. Finally I sketch the intervening changes in behaviour over time, the sharpest of which brought about the rise of atmospheric oxygen at ~2.25Ga. Core formation. As the very high specific angular momentum of mean planetary material (>105-fold relative to solar) can only be achieved if the planets were wholly accreted in presence of the nebula [1], the iron percolation model is ruled out, because it takes too long. This validates the A.E.Ringwood model (1960-1978) involving nebular H reaction with erupting FeO. The iron then loads the downgoing limb of what is then not a truly thermal convection system. Huge volumes of reaction water were produced, giving the early Earth a wet mantle, a (diminishing) feature that we'll see has constrained mantle behaviour ever since. Plate dynamics since 150Ma. Multiple plate dynamical evidence [2], which will be rapidly re-presented here, shows that currently (a) the Earth has a 2-layer mantle system with a boundary at ~660km and (b) that most cratons have tectospheric keels that reach right to that boundary, or nearly so. The argument is the simple and persuasive one (even to seismologists) of mantle

  16. 45 CFR 612.5 - Timing of responses to requests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 3 2011-10-01 2011-10-01 false Timing of responses to requests. 612.5 Section 612.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION... requester who is not a full-time member of the news media must establish that he or she is a person...

  17. 45 CFR 612.5 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Timing of responses to requests. 612.5 Section 612.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION... requester who is not a full-time member of the news media must establish that he or she is a person...

  18. 45 CFR 612.5 - Timing of responses to requests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 3 2012-10-01 2012-10-01 false Timing of responses to requests. 612.5 Section 612.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION... requester who is not a full-time member of the news media must establish that he or she is a person...

  19. Conceptual Question Response Times in Peer Instruction Classrooms

    ERIC Educational Resources Information Center

    Miller, Kelly; Lasry, Nathaniel; Lukoff, Brian; Schell, Julie; Mazur, Eric

    2014-01-01

    Classroom response systems are widely used in interactive teaching environments as a way to engage students by asking them questions. Previous research on the time taken by students to respond to conceptual questions has yielded insights on how students think and change conceptions. We measure the amount of time students take to respond to…

  20. The actual goals of geoethics

    NASA Astrophysics Data System (ADS)

    Nemec, Vaclav

    2014-05-01

    The most actual goals of geoethics have been formulated as results of the International Conference on Geoethics (October 2013) held at the geoethics birth-place Pribram (Czech Republic): In the sphere of education and public enlightenment an appropriate needed minimum know how of Earth sciences should be intensively promoted together with cultivating ethical way of thinking and acting for the sustainable well-being of the society. The actual activities of the Intergovernmental Panel of Climate Changes are not sustainable with the existing knowledge of the Earth sciences (as presented in the results of the 33rd and 34th International Geological Congresses). This knowledge should be incorporated into any further work of the IPCC. In the sphere of legislation in a large international co-operation following steps are needed: - to re-formulate the term of a "false alarm" and its legal consequences, - to demand very consequently the needed evaluation of existing risks, - to solve problems of rights of individuals and minorities in cases of the optimum use of mineral resources and of the optimum protection of the local population against emergency dangers and disasters; common good (well-being) must be considered as the priority when solving ethical dilemmas. The precaution principle should be applied in any decision making process. Earth scientists presenting their expert opinions are not exempted from civil, administrative or even criminal liabilities. Details must be established by national law and jurisprudence. The well known case of the L'Aquila earthquake (2009) should serve as a serious warning because of the proven misuse of geoethics for protecting top Italian seismologists responsible and sentenced for their inadequate superficial behaviour causing lot of human victims. Another recent scandal with the Himalayan fossil fraud will be also documented. A support is needed for any effort to analyze and to disclose the problems of the deformation of the contemporary

  1. A Conditional Joint Modeling Approach for Locally Dependent Item Responses and Response Times

    ERIC Educational Resources Information Center

    Meng, Xiang-Bin; Tao, Jian; Chang, Hua-Hua

    2015-01-01

    The assumption of conditional independence between the responses and the response times (RTs) for a given person is common in RT modeling. However, when the speed of a test taker is not constant, this assumption will be violated. In this article we propose a conditional joint model for item responses and RTs, which incorporates a covariance…

  2. Speed-Accuracy Response Models: Scoring Rules Based on Response Time and Accuracy

    ERIC Educational Resources Information Center

    Maris, Gunter; van der Maas, Han

    2012-01-01

    Starting from an explicit scoring rule for time limit tasks incorporating both response time and accuracy, and a definite trade-off between speed and accuracy, a response model is derived. Since the scoring rule is interpreted as a sufficient statistic, the model belongs to the exponential family. The various marginal and conditional distributions…

  3. Monitoring the immune response using real-time PCR.

    PubMed

    Stordeur, Patrick

    2009-01-01

    Induction of an immune response to a particular antigen is the basis of vaccination. This has been done for years to prevent infectious diseases, and has the potential for the treatment of cancer. The immune response is nowadays more precisely modulated rather than simply induced, like in case of immunotherapy of allergic diseases. Likewise, autoimmune diseases are associated with an inappropriate immune response, and many efforts are made for specifically inhibiting this unwanted response. A possible line of attack is the induction of an antigen-specific immune tolerance, which also has a use in the field of transplantation, where allogeneic responses are deleterious for the graft. In all of these fields of fundamental and clinical medicine, the modulation of immune response requires the assistance of laboratory tests, among which real-time PCR appears more and more helpful. This chapter describes a protocol to quantify immune-related mRNAs using reverse transcription-real-time PCR. The transcripts can be quantified in cultured cells or in cultured whole blood, after an incubation period in the presence of the antigen to which the immune response is analyzed. This is the typical approach to evaluate the efficacy of a vaccine. The transcripts can also be quantified directly in the biological sample, giving information about the in vivo immune status of the individual. The techniques to achieve these different methods are described, and are illustrated by the analysis of the response against the toxoid tetanus antigen.

  4. Conceptual question response times in Peer Instruction classrooms

    NASA Astrophysics Data System (ADS)

    Miller, Kelly; Lasry, Nathaniel; Lukoff, Brian; Schell, Julie; Mazur, Eric

    2014-12-01

    Classroom response systems are widely used in interactive teaching environments as a way to engage students by asking them questions. Previous research on the time taken by students to respond to conceptual questions has yielded insights on how students think and change conceptions. We measure the amount of time students take to respond to in-class, conceptual questions [ConcepTests (CTs)] in two introductory physics courses taught using Peer Instruction and use item response theory to determine the difficulty of the CTs. We examine response time differences between correct and incorrect answers both before and after the peer discussion for CTs of varying difficulty. We also determine the relationship between response time and student performance on a standardized test of incoming physics knowledge, precourse self-efficacy, and gender. Our data reveal three results of interest. First, response time for correct answers is significantly faster than for incorrect answers, both before and after peer discussion, especially for easy CTs. Second, students with greater incoming physics knowledge and higher self-efficacy respond faster in both rounds. Third, there is no gender difference in response rate after controlling for incoming physics knowledge scores, although males register significantly more attempts before committing to a final answer than do female students. These results provide insight into effective CT pacing during Peer Instruction. In particular, in order to maintain a pace that keeps everyone engaged, students should not be given too much time to respond. When around 80% of the answers are in, the ratio of correct to incorrect responses rapidly approaches levels indicating random guessing and instructors should close the poll.

  5. Timing of anticipatory muscle tensing control: responses before and after expected impact.

    PubMed

    Vishton, Peter M; Reardon, Kristin M; Stevens, Jennifer A

    2010-05-01

    It is widely accepted that human motor control is anticipatory in nature. Previous studies have used electromyography (EMG) to examine muscle responses to falling objects and identified anticipatory muscle tensing (AMT) as a spike in activation that occurs prior to object impact. Some studies have suggested that humans use an internal model of gravity to mediate precisely timed AMT responses. The present study further examines predictive motor control through the analysis of AMT during an object catching task. For some trials, participants watched an object falling toward the hand; for other trials, their eyes were closed. For some trials, the object fell downward and impacted the hand; for other randomly selected trials, the object abruptly stopped 12 cm above the hand, enabling an assessment of the effect of impact anticipation independent of the reflexive tactile response associated with an actual impact. In Experiment 1, AMT did not shift for approximately 113 ms after the abrupt stop of the ball. In Experiment 2, we randomly varied the start height of the object and found well-timed AMT with a 129-ms lag time. A control system based on simple memory for fall time duration cannot explain these findings. We argue that an AMT control system with a lag time of approximately 121 ms could not perform with human levels of accuracy without accounting for the acceleration of downward moving objects. PMID:20135099

  6. Timing of anticipatory muscle tensing control: responses before and after expected impact.

    PubMed

    Vishton, Peter M; Reardon, Kristin M; Stevens, Jennifer A

    2010-05-01

    It is widely accepted that human motor control is anticipatory in nature. Previous studies have used electromyography (EMG) to examine muscle responses to falling objects and identified anticipatory muscle tensing (AMT) as a spike in activation that occurs prior to object impact. Some studies have suggested that humans use an internal model of gravity to mediate precisely timed AMT responses. The present study further examines predictive motor control through the analysis of AMT during an object catching task. For some trials, participants watched an object falling toward the hand; for other trials, their eyes were closed. For some trials, the object fell downward and impacted the hand; for other randomly selected trials, the object abruptly stopped 12 cm above the hand, enabling an assessment of the effect of impact anticipation independent of the reflexive tactile response associated with an actual impact. In Experiment 1, AMT did not shift for approximately 113 ms after the abrupt stop of the ball. In Experiment 2, we randomly varied the start height of the object and found well-timed AMT with a 129-ms lag time. A control system based on simple memory for fall time duration cannot explain these findings. We argue that an AMT control system with a lag time of approximately 121 ms could not perform with human levels of accuracy without accounting for the acceleration of downward moving objects.

  7. Peripheral visual response time and retinal luminance-area relations

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1975-01-01

    Experiments were undertaken to elucidate the stimulus luminance-retinal area relationship that underlies response time (RT) behavior. Mean RT was significantly faster to stimuli imaged beyond about 70 deg of arc from the fovea when their luminance was increased by an amount equal to the foveal stimulus luminance multiplied by the cosine of the angle between the peripheral stimuli and the line of sight. This and additional data are discussed in relation to previous psychophysical data and to possible response mechanisms.

  8. Time domains of the hypoxic ventilatory response in ectothermic vertebrates.

    PubMed

    Porteus, Cosima; Hedrick, Michael S; Hicks, James W; Wang, Tobias; Milsom, William K

    2011-04-01

    Over a decade has passed since Powell et al. (Respir Physiol 112:123-134, 1998) described and defined the time domains of the hypoxic ventilatory response (HVR) in adult mammals. These time domains, however, have yet to receive much attention in other vertebrate groups. The initial, acute HVR of fish, amphibians and reptiles serves to minimize the imbalance between oxygen supply and demand. If the hypoxia is sustained, a suite of secondary adjustments occur giving rise to a more long-term balance (acclimatization) that allows the behaviors of normal life. These secondary responses can change over time as a function of the nature of the stimulus (the pattern and intensity of the hypoxic exposure). To add to the complexity of this process, hypoxia can also lead to metabolic suppression (the hypoxic metabolic response) and the magnitude of this is also time dependent. Unlike the original review of Powell et al. (Respir Physiol 112:123-134, 1998) that only considered the HVR in adult animals, we also consider relevant developmental time points where information is available. Finally, in amphibians and reptiles with incompletely divided hearts the magnitude of the ventilatory response will be modulated by hypoxia-induced changes in intra-cardiac shunting that also improve the match between O(2) supply and demand, and these too change in a time-dependent fashion. While the current literature on this topic is reviewed here, it is noted that this area has received little attention. We attempt to redefine time domains in a more 'holistic' fashion that better accommodates research on ectotherms. If we are to distinguish between the genetic, developmental and environmental influences underlying the various ventilatory responses to hypoxia, however, we must design future experiments with time domains in mind. PMID:21312038

  9. Dynamic Response of an Optomechanical System to a Stationary Random Excitation in the Time Domain

    DOE PAGES

    Palmer, Jeremy A.; Paez, Thomas L.

    2011-01-01

    Modern electro-optical instruments are typically designed with assemblies of optomechanical members that support optics such that alignment is maintained in service environments that include random vibration loads. This paper presents a nonlinear numerical analysis that calculates statistics for the peak lateral response of optics in an optomechanical sub-assembly subject to random excitation of the housing. The work is unique in that the prior art does not address peak response probability distribution for stationary random vibration in the time domain for a common lens-retainer-housing system with Coulomb damping. Analytical results are validated by using displacement response data from random vibration testingmore » of representative prototype sub-assemblies. A comparison of predictions to experimental results yields reasonable agreement. The Type I Asymptotic form provides the cumulative distribution function for peak response probabilities. Probabilities are calculated for actual lens centration tolerances. The probability that peak response will not exceed the centration tolerance is greater than 80% for prototype configurations where the tolerance is high (on the order of 30 micrometers). Conversely, the probability is low for those where the tolerance is less than 20 micrometers. The analysis suggests a design paradigm based on the influence of lateral stiffness on the magnitude of the response.« less

  10. Assessing recognition memory using confidence ratings and response times

    PubMed Central

    Kahana, Michael J.

    2016-01-01

    Classification of stimuli into categories (such as ‘old’ and ‘new’ in tests of recognition memory or ‘present’ versus ‘absent’ in signal detection tasks) requires the mapping of internal signals to discrete responses. Introspective judgements about a given choice response are regularly employed in research, legal and clinical settings in an effort to measure the signal that is thought to be the basis of the classification decision. Correlations between introspective judgements and task performance suggest that such ratings often do convey information about internal states that are relevant for a given task, but well-known limitations of introspection call the fidelity of this information into question. We investigated to what extent response times can reveal information usually assessed with explicit confidence ratings. We quantitatively compared response times to confidence ratings in their ability to qualify recognition memory decisions and found convergent results suggesting that much of the information from confidence ratings can be obtained from response times. PMID:27152209

  11. Malignant glioma - timing of response to radiation therapy

    SciTech Connect

    Gaspar, L.E.; Fisher, B.J.; MacDonald, D.R.; Cairncross, J.G. London Regional Cancer Centre, Ontario ); LeBer, D.V. ); Halperin, E.C.; Schold, S.C. Jr. )

    1993-04-02

    The response of malignant gliomas to radiation was examined retrospectively in 71 patients with newly diagnosed supratentorial malignant gliomas. Questions asked included frequency, timing and clinical significance of response. After surgery, all were treated with whole brain plus boost radiotherapy followed 8 weeks later by chemotherapy. The rate, degree, and timing of response to radiation were determined by comparing postoperative, end of radiation, and prechemotherapy CT scans on each patient. Postoperative residual tumor was evident on 63/71 postoperative scans. Twenty-two of 63 tumors (35%) had a partial or complete response to radiation. Twenty (32%) had responded by the end of radiation; 17 maximally. Six to 8 weeks later, three responding tumors had responded further and two previously stable ones had begun to respond. Only three tumors (5%) responded completely. A greater proportion of anaplastic gliomas than glioblastomas responded to radiation (52% vs. 26%). Protracted or delayed responses were only observed in patients with anaplastic glioma. Patients who responded to radiation did not live significantly longer than non-responders. However, tumor progression prior to chemotherapy was associated with significantly shorter survival. This CT scan-based analysis demonstrates that malignant gliomas are only moderately radioresponsive tumors and also demonstrates that response to radiation, if it is going to occur, is usually evident by the end of treatment. 6 refs., 1 fig., 1 tab.

  12. A mechanism for error detection in speeded response time tasks.

    PubMed

    Holroyd, Clay B; Yeung, Nick; Coles, Michael G H; Cohen, Jonathan D

    2005-05-01

    The concept of error detection plays a central role in theories of executive control. In this article, the authors present a mechanism that can rapidly detect errors in speeded response time tasks. This error monitor assigns values to the output of cognitive processes involved in stimulus categorization and response generation and detects errors by identifying states of the system associated with negative value. The mechanism is formalized in a computational model based on a recent theoretical framework for understanding error processing in humans (C. B. Holroyd & M. G. H. Coles, 2002). The model is used to simulate behavioral and event-related brain potential data in a speeded response time task, and the results of the simulation are compared with empirical data.

  13. Climate response times: dependence on climate sensitivity and ocean mixing

    SciTech Connect

    Hansen, J.; Russell, G.; Lacis, A.; Fung, I.; Rind, D.; Stone, P.

    1985-08-30

    The factors that determine climate response times were investigated with simple models and scaling statements. The response times are particularly sensitive to (1) the amount that the climate response is amplified by feedbacks and (2) the representation of ocean mixing. If equilibrium climate sensitivity is 3/sup 0/C or greater for a doubling of the carbon dioxide concentration, then most of the expected warming attributable to trace gases added to the atmosphere by man probably has not yet occurred. This yet to be realized warming calls into question a policy of wait and see regarding the issue of how to deal with increasing atmospheric carbon dioxide and other trace gases. 17 references, 2 figures.

  14. Separability of Item and Person Parameters in Response Time Models.

    ERIC Educational Resources Information Center

    Van Breukelen, Gerard J. P.

    1997-01-01

    Discusses two forms of separability of item and person parameters in the context of response time models. The first is "separate sufficiency," and the second is "ranking independence." For each form a theorem stating sufficient conditions is proved. The two forms are shown to include several cases of models from psychometric and biometric…

  15. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  16. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  17. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  18. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  19. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  20. 45 CFR 612.5 - Timing of responses to requests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 3 2013-10-01 2013-10-01 false Timing of responses to requests. 612.5 Section 612.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION... news media must establish that he or she is a person whose main professional activity or occupation...

  1. 45 CFR 612.5 - Timing of responses to requests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 3 2014-10-01 2014-10-01 false Timing of responses to requests. 612.5 Section 612.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION... news media must establish that he or she is a person whose main professional activity or occupation...

  2. 18 CFR 1301.5 - Timing of responses to requests.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Timing of responses to requests. 1301.5 Section 1301.5 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY... is most efficient in each case. (1) Track 1. Requests that can be answered with readily...

  3. 18 CFR 1301.5 - Timing of responses to requests.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Timing of responses to requests. 1301.5 Section 1301.5 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY... is most efficient in each case. (1) Track 1. Requests that can be answered with readily...

  4. 18 CFR 1301.5 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Timing of responses to requests. 1301.5 Section 1301.5 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY... is most efficient in each case. (1) Track 1. Requests that can be answered with readily...

  5. 18 CFR 1301.5 - Timing of responses to requests.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Timing of responses to requests. 1301.5 Section 1301.5 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY... is most efficient in each case. (1) Track 1. Requests that can be answered with readily...

  6. 18 CFR 1301.5 - Timing of responses to requests.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Timing of responses to requests. 1301.5 Section 1301.5 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY... is most efficient in each case. (1) Track 1. Requests that can be answered with readily...

  7. Distinct Response Time Distributions in Attention Deficit Hyperactivity Disorder Subtypes

    ERIC Educational Resources Information Center

    Querne, Laurent; Berquin, Patrick

    2009-01-01

    Objective: To address the issue of response time (RT) profiles in hyperactive-impulsive (ADHD-HI), inattentive (ADHD-IA), and combined (ADHD-C) subtypes of ADHD. We hypothesized that children with ADHD-HI should respond more rapidly than children without ADHD and children with ADHD-IA and ADHD-C should respond more slowly than children without…

  8. Processing Time Shifts Affects the Execution of Motor Responses

    ERIC Educational Resources Information Center

    Sell, Andrea J.; Kaschak, Michael P.

    2011-01-01

    We explore whether time shifts in text comprehension are represented spatially. Participants read sentences involving past or future events and made sensibility judgment responses in one of two ways: (1) moving toward or away from their body and (2) pressing the toward or away buttons without moving. Previous work suggests that spatial…

  9. 40 CFR 1066.245 - Response time verification.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... automated process to verify response time. You may perform this test either at two different inertia... base inertia and two acceleration rates that cover the range of acceleration rates experienced during... less than 100 milliseconds for each inertia setting. ER28AP14.066...

  10. 36 CFR 1600.4 - Timing of responses to requests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Timing of responses to requests. 1600.4 Section 1600.4 Parks, Forests, and Public Property MORRIS K. UDALL SCHOLARSHIP AND EXCELLENCE IN NATIONAL ENVIRONMENTAL POLICY FOUNDATION PUBLIC AVAILABILITY OF DOCUMENTS AND RECORDS Procedures for Disclosure of Records Under the...

  11. Modeling Information Accumulation in Psychological Tests Using Item Response Times

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jörg-Tobias

    2015-01-01

    In this article, a latent trait model is proposed for the response times in psychological tests. The latent trait model is based on the linear transformation model and subsumes popular models from survival analysis, like the proportional hazards model and the proportional odds model. Core of the model is the assumption that an unspecified monotone…

  12. From Zero to Sixty: Calibrating Real-Time Responses

    ERIC Educational Resources Information Center

    Koulis, Theodoro; Ramsay, James O.; Levitin, Daniel J.

    2008-01-01

    Recent advances in data recording technology have given researchers new ways of collecting on-line and continuous data for analyzing input-output systems. For example, continuous response digital interfaces are increasingly used in psychophysics. The statistical problem related to these input-output systems reduces to linking time-varying…

  13. 36 CFR 1600.4 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Timing of responses to requests. 1600.4 Section 1600.4 Parks, Forests, and Public Property MORRIS K. UDALL SCHOLARSHIP AND EXCELLENCE IN NATIONAL ENVIRONMENTAL POLICY FOUNDATION PUBLIC AVAILABILITY OF DOCUMENTS AND...

  14. Timing and Causality in the Generation of Learned Eyelid Responses

    PubMed Central

    Sánchez-Campusano, Raudel; Gruart, Agnès; Delgado-García, José M.

    2011-01-01

    The cerebellum-red nucleus-facial motoneuron (Mn) pathway has been reported as being involved in the proper timing of classically conditioned eyelid responses. This special type of associative learning serves as a model of event timing for studying the role of the cerebellum in dynamic motor control. Here, we have re-analyzed the firing activities of cerebellar posterior interpositus (IP) neurons and orbicularis oculi (OO) Mns in alert behaving cats during classical eyeblink conditioning, using a delay paradigm. The aim was to revisit the hypothesis that the IP neurons (IPns) can be considered a neuronal phase-modulating device supporting OO Mns firing with an emergent timing mechanism and an explicit correlation code during learned eyelid movements. Optimized experimental and computational tools allowed us to determine the different causal relationships (temporal order and correlation code) during and between trials. These intra- and inter-trial timing strategies expanding from sub-second range (millisecond timing) to longer-lasting ranges (interval timing) expanded the functional domain of cerebellar timing beyond motor control. Interestingly, the results supported the above-mentioned hypothesis. The causal inferences were influenced by the precise motor and pre-motor spike timing in the cause-effect interval, and, in addition, the timing of the learned responses depended on cerebellar–Mn network causality. Furthermore, the timing of CRs depended upon the probability of simulated causal conditions in the cause-effect interval and not the mere duration of the inter-stimulus interval. In this work, the close relation between timing and causality was verified. It could thus be concluded that the firing activities of IPns may be related more to the proper performance of ongoing CRs (i.e., the proper timing as a consequence of the pertinent causality) than to their generation and/or initiation. PMID:21941469

  15. Aircraft Fault Detection Using Real-Time Frequency Response Estimation

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.

    2016-01-01

    A real-time method for estimating time-varying aircraft frequency responses from input and output measurements was demonstrated. The Bat-4 subscale airplane was used with NASA Langley Research Center's AirSTAR unmanned aerial flight test facility to conduct flight tests and collect data for dynamic modeling. Orthogonal phase-optimized multisine inputs, summed with pilot stick and pedal inputs, were used to excite the responses. The aircraft was tested in its normal configuration and with emulated failures, which included a stuck left ruddervator and an increased command path latency. No prior knowledge of a dynamic model was used or available for the estimation. The longitudinal short period dynamics were investigated in this work. Time-varying frequency responses and stability margins were tracked well using a 20 second sliding window of data, as compared to a post-flight analysis using output error parameter estimation and a low-order equivalent system model. This method could be used in a real-time fault detection system, or for other applications of dynamic modeling such as real-time verification of stability margins during envelope expansion tests.

  16. Adaptive Responses to Prochloraz Exposure That Alter Dose-Response and Time-Course Behaviors

    EPA Science Inventory

    Dose response and time-course (DRTC) are, along with exposure, the major determinants of health risk. Adaptive changes within exposed organisms in response to environmental stress are common, and alter DRTC behaviors to minimize the effects caused by stressors. In this project, ...

  17. The Time Course Effect of Moderate Intensity Exercise on Response Execution and Response Inhibition

    ERIC Educational Resources Information Center

    Joyce, Jennifer; Graydon, Jan; McMorris, Terry; Davranche, Karen

    2009-01-01

    This research aimed to investigate the time course effect of a moderate steady-state exercise session on response execution and response inhibition using a stop-task paradigm. Ten participants performed a stop-signal task whilst cycling at a carefully controlled workload intensity (40% of maximal aerobic power), immediately following exercise and…

  18. Time dependency of craving and response inhibition during nicotine abstinence

    PubMed Central

    Tsaur, Stephen; Strasser, Andrew A.; Souprountchouk, Valentina; Evans, Gretchen C.; Ashare, Rebecca L.

    2015-01-01

    Background Nicotine withdrawal produces increased craving for cigarettes and deficits in response inhibition, and these withdrawal symptoms are predictive of relapse. Although it is well-established that these symptoms emerge early during abstinence, there is mixed evidence regarding whether they occur simultaneously. Given the importance of the early withdrawal period, this study examined craving and response inhibition at 24h and 72h abstinence. Methods Twenty-one non-treatment seeking adult smokers were evaluated at baseline, 24h, and 72h abstinence for craving (Questionnaire on Smoking Urges – Brief) and response inhibition (Stop Signal Task, Stroop Task, Continuous Performance Task). Generalized linear regression models were used for primary outcomes, and Pearson correlations for examining the association between craving and response inhibition. Results Factor 2 craving (anticipated relief of negative affect) increased from baseline to 24h abstinent (p=0.004), which subsided by 72h (p=0.08). Deficits in response inhibition measured by the Stop Signal Task were observed at 72h (p=0.046), but not 24h (p=0.318). No correlation was found between response inhibition and craving at any time point (p-values>0.19), except between the Stroop Task and factor 1 craving at baseline (p=0.025). Conclusions Factor 2 craving peaked at 24h, whereas deficits in response inhibition did not emerge until 72h, indicating that need to target craving and cognitive function during early abstinence may not occur simultaneously. Further characterizing the time course of withdrawal symptoms may guide development of targeted treatments for smoking cessation. PMID:26052265

  19. Modeling in Real Time During the Ebola Response.

    PubMed

    Meltzer, Martin I; Santibanez, Scott; Fischer, Leah S; Merlin, Toby L; Adhikari, Bishwa B; Atkins, Charisma Y; Campbell, Caresse; Fung, Isaac Chun-Hai; Gambhir, Manoj; Gift, Thomas; Greening, Bradford; Gu, Weidong; Jacobson, Evin U; Kahn, Emily B; Carias, Cristina; Nerlander, Lina; Rainisch, Gabriel; Shankar, Manjunath; Wong, Karen; Washington, Michael L

    2016-01-01

    To aid decision-making during CDC's response to the 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa, CDC activated a Modeling Task Force to generate estimates on various topics related to the response in West Africa and the risk for importation of cases into the United States. Analysis of eight Ebola response modeling projects conducted during August 2014-July 2015 provided insight into the types of questions addressed by modeling, the impact of the estimates generated, and the difficulties encountered during the modeling. This time frame was selected to cover the three phases of the West African epidemic curve. Questions posed to the Modeling Task Force changed as the epidemic progressed. Initially, the task force was asked to estimate the number of cases that might occur if no interventions were implemented compared with cases that might occur if interventions were implemented; however, at the peak of the epidemic, the focus shifted to estimating resource needs for Ebola treatment units. Then, as the epidemic decelerated, requests for modeling changed to generating estimates of the potential number of sexually transmitted Ebola cases. Modeling to provide information for decision-making during the CDC Ebola response involved limited data, a short turnaround time, and difficulty communicating the modeling process, including assumptions and interpretation of results. Despite these challenges, modeling yielded estimates and projections that public health officials used to make key decisions regarding response strategy and resources required. The impact of modeling during the Ebola response demonstrates the usefulness of modeling in future responses, particularly in the early stages and when data are scarce. Future modeling can be enhanced by planning ahead for data needs and data sharing, and by open communication among modelers, scientists, and others to ensure that modeling and its limitations are more clearly understood. The activities summarized in

  20. How People Actually Use Thermostats

    SciTech Connect

    Meier, Alan; Aragon, Cecilia; Hurwitz, Becky; Mujumdar, Dhawal; Peffer, Therese; Perry, Daniel; Pritoni, Marco

    2010-08-15

    Residential thermostats have been a key element in controlling heating and cooling systems for over sixty years. However, today's modern programmable thermostats (PTs) are complicated and difficult for users to understand, leading to errors in operation and wasted energy. Four separate tests of usability were conducted in preparation for a larger study. These tests included personal interviews, an on-line survey, photographing actual thermostat settings, and measurements of ability to accomplish four tasks related to effective use of a PT. The interviews revealed that many occupants used the PT as an on-off switch and most demonstrated little knowledge of how to operate it. The on-line survey found that 89% of the respondents rarely or never used the PT to set a weekday or weekend program. The photographic survey (in low income homes) found that only 30% of the PTs were actually programmed. In the usability test, we found that we could quantify the difference in usability of two PTs as measured in time to accomplish tasks. Users accomplished the tasks in consistently shorter times with the touchscreen unit than with buttons. None of these studies are representative of the entire population of users but, together, they illustrate the importance of improving user interfaces in PTs.

  1. Ampoule failure sensor time response testing: Experiments 2 and 3

    NASA Astrophysics Data System (ADS)

    Johnson, M. L.; Watring, D. A.

    1994-06-01

    The response time of an ampoule failure sensor exposed to a liquid or vapor gallium-arsenide (GaAs) and the corresponding breach time of the containing cartridge is investigated. The experiments were conducted in niobium-hafnium (WC-103) cartridges with an exterior silicide coating. These cartridges were built to flight specifications that were used in NASA's Crystal Growth Furnace during the first United States Microgravity Laboratory (USML-1) mission. The ampoule failure sensor is a chemical fuse made from a metal with which the semiconductor material reacts more rapidly than it does with the containing cartridge. In these experiments a platinum metal was used for the manufacture of the sensors. This technical report discusses the response time of two different sensor designs. The first design utilizes a helical wrapped wire and the second uses a single bare wire element. Experimental results indicate that both sensors are adequate in sensing the presence of molten or vapor GaAs with the latter having a 2-minute longer response time. In both experiments, the containing cartridge was breached within 185 minutes after ampoule rupture.

  2. Ampoule failure sensor time response testing: Experiments 2 and 3

    NASA Technical Reports Server (NTRS)

    Johnson, M. L.; Watring, D. A.

    1994-01-01

    The response time of an ampoule failure sensor exposed to a liquid or vapor gallium-arsenide (GaAs) and the corresponding breach time of the containing cartridge is investigated. The experiments were conducted in niobium-hafnium (WC-103) cartridges with an exterior silicide coating. These cartridges were built to flight specifications that were used in NASA's Crystal Growth Furnace during the first United States Microgravity Laboratory (USML-1) mission. The ampoule failure sensor is a chemical fuse made from a metal with which the semiconductor material reacts more rapidly than it does with the containing cartridge. In these experiments a platinum metal was used for the manufacture of the sensors. This technical report discusses the response time of two different sensor designs. The first design utilizes a helical wrapped wire and the second uses a single bare wire element. Experimental results indicate that both sensors are adequate in sensing the presence of molten or vapor GaAs with the latter having a 2-minute longer response time. In both experiments, the containing cartridge was breached within 185 minutes after ampoule rupture.

  3. Ultimate response time of high electron mobility transistors

    SciTech Connect

    Rudin, Sergey; Rupper, Greg; Shur, Michael

    2015-05-07

    We present theoretical studies of the response time of the two-dimensional gated electron gas to femtosecond pulses. Our hydrodynamic simulations show that the device response to a short pulse or a step-function signal is either smooth or oscillating time-decay at low and high mobility, μ, values, respectively. At small gate voltage swings, U{sub 0} = U{sub g} − U{sub th}, where U{sub g} is the gate voltage and U{sub th} is the threshold voltage, such that μU{sub 0}/L < v{sub s}, where L is the channel length and v{sub s} is the effective electron saturation velocity, the decay time in the low mobility samples is on the order of L{sup 2}/(μU{sub 0}), in agreement with the analytical drift model. However, the decay is preceded by a delay time on the order of L/s, where s is the plasma wave velocity. This delay is the ballistic transport signature in collision-dominated devices, which becomes important during very short time periods. In the high mobility devices, the period of the decaying oscillations is on the order of the plasma wave velocity transit time. Our analysis shows that short channel field effect transistors operating in the plasmonic regime can meet the requirements for applications as terahertz detectors, mixers, delay lines, and phase shifters in ultra high-speed wireless communication circuits.

  4. Time-dependent response of filamentary composite spherical pressure vessels

    NASA Technical Reports Server (NTRS)

    Dozier, J. D.

    1983-01-01

    A filamentary composite spherical pressure vessel is modeled as a pseudoisotropic (or transversely isotropic) composite shell, with the effects of the liner and fill tubes omitted. Equations of elasticity, macromechanical and micromechanical formulations, and laminate properties are derived for the application of an internally pressured spherical composite vessel. Viscoelastic properties for the composite matrix are used to characterize time-dependent behavior. Using the maximum strain theory of failure, burst pressure and critical strain equations are formulated, solved in the Laplace domain with an associated elastic solution, and inverted back into the time domain using the method of collocation. Viscoelastic properties of HBFR-55 resin are experimentally determined and a Kevlar/HBFR-55 system is evaluated with a FORTRAN program. The computed reduction in burst pressure with respect to time indicates that the analysis employed may be used to predict the time-dependent response of a filamentary composite spherical pressure vessel.

  5. Exact response functions within the time-dependent Gutzwiller approach

    NASA Astrophysics Data System (ADS)

    Bünemann, J.; Wasner, S.; Oelsen, E. v.; Seibold, G.

    2015-02-01

    We investigate the applicability of the two existing versions of a time-dependent Gutzwiller approach (TDGA) beyond the frequently used limit of infinite spatial dimensions. To this end, we study the two-particle response functions of a two-site Hubbard model where we can compare the exact results and those derived from the TDGA. It turns out that only the more recently introduced version of the TDGA can be combined with a diagrammatic approach which allows for the evaluation of Gutzwiller wave functions in finite dimensions. For this TDGA method, we derive the time-dependent Lagrangian for general single-band Hubbard models.

  6. Noncausal time response in frustrated total internal reflection?

    PubMed

    Carey; Zawadzka; Jaroszynski; Wynne

    2000-02-14

    Tunneling of photons in frustrated total internal reflection has been studied in the time domain with single-cycle femtosecond pulses. It is seen that both the phase and energy of the pulse travel faster than the speed of light in vacuum. Theoretical analysis of the experiments shows that the time-response function for electromagnetic waves propagating in the air gap is noncausal. However, it is found that superluminal signal propagation is not possible in this case because of the inevitable diffractive spreading of the signal beam.

  7. Collecting response times using Amazon Mechanical Turk and Adobe Flash.

    PubMed

    Simcox, Travis; Fiez, Julie A

    2014-03-01

    Crowdsourcing systems like Amazon's Mechanical Turk (AMT) allow data to be collected from a large sample of people in a short amount of time. This use has garnered considerable interest from behavioral scientists. So far, most experiments conducted on AMT have focused on survey-type instruments because of difficulties inherent in running many experimental paradigms over the Internet. This study investigated the viability of presenting stimuli and collecting response times using Adobe Flash to run ActionScript 3 code in conjunction with AMT. First, the timing properties of Adobe Flash were investigated using a phototransistor and two desktop computers running under several conditions mimicking those that may be present in research using AMT. This experiment revealed some strengths and weaknesses of the timing capabilities of this method. Next, a flanker task and a lexical decision task implemented in Adobe Flash were administered to participants recruited with AMT. The expected effects in these tasks were replicated. Power analyses were conducted to describe the number of participants needed to replicate these effects. A questionnaire was used to investigate previously undescribed computer use habits of 100 participants on AMT. We conclude that a Flash program in conjunction with AMT can be successfully used for running many experimental paradigms that rely on response times, although experimenters must understand the limitations of the method.

  8. High frequency dielectrophoretic response of microalgae over time

    PubMed Central

    Hadady, Hanieh; Wong, Johnson J.; Hiibel, Sage R.; Redelman, Doug; Geiger, Emil J.

    2015-01-01

    The high frequency dielectrophoresis (>20 MHz) response of microalgae cells with different lipid content was monitored over time. Chlamydomonas reinhardtii was cultured in regular medium and under nitrogen-depleted conditions in order to produce populations of cells with low and high lipid content, respectively. The electrical conductivity (EC) of the culture media was also monitored over the same time. The upper crossover frequency (UCOF) decreased for high-lipid cells over time. The single-shell model predicts that the upper crossover frequency is dictated primarily by the dielectric properties of the cytoplasm. The high frequency DEP response of the high-lipid cells’ cytoplasm was changed by lipid accumulation. DEP response of the low-lipid cells also varied with the conductivity of the culture media due to nutrient consumption. Relative lipid content was estimated with BODIPY 505/515 dye by calculating the area-weighted intensity average of fluorescent images. Finally, microalgae cells were successfully separated based on lipid content at 41 MHz and DEP media conductivity 106 ± 1 µS/cm. PMID:25229637

  9. Equivalent Effects of Grouping by Time, Voice, and Location on Response Timing in Verbal Serial Memory

    ERIC Educational Resources Information Center

    Parmentier, Fabrice B. R.; Maybery, Murray T.

    2008-01-01

    The grouping of list items is known to improve serial memory accuracy and constrain the nature of temporal errors. A recent study (M. T. Maybery, F. B. R. Parmentier, & D. M. Jones, 2002) showed that grouping results in a temporal organization of the participants' responses that mimics the list structure but not the timing of its presentation.…

  10. Modeling in Real Time During the Ebola Response.

    PubMed

    Meltzer, Martin I; Santibanez, Scott; Fischer, Leah S; Merlin, Toby L; Adhikari, Bishwa B; Atkins, Charisma Y; Campbell, Caresse; Fung, Isaac Chun-Hai; Gambhir, Manoj; Gift, Thomas; Greening, Bradford; Gu, Weidong; Jacobson, Evin U; Kahn, Emily B; Carias, Cristina; Nerlander, Lina; Rainisch, Gabriel; Shankar, Manjunath; Wong, Karen; Washington, Michael L

    2016-01-01

    To aid decision-making during CDC's response to the 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa, CDC activated a Modeling Task Force to generate estimates on various topics related to the response in West Africa and the risk for importation of cases into the United States. Analysis of eight Ebola response modeling projects conducted during August 2014-July 2015 provided insight into the types of questions addressed by modeling, the impact of the estimates generated, and the difficulties encountered during the modeling. This time frame was selected to cover the three phases of the West African epidemic curve. Questions posed to the Modeling Task Force changed as the epidemic progressed. Initially, the task force was asked to estimate the number of cases that might occur if no interventions were implemented compared with cases that might occur if interventions were implemented; however, at the peak of the epidemic, the focus shifted to estimating resource needs for Ebola treatment units. Then, as the epidemic decelerated, requests for modeling changed to generating estimates of the potential number of sexually transmitted Ebola cases. Modeling to provide information for decision-making during the CDC Ebola response involved limited data, a short turnaround time, and difficulty communicating the modeling process, including assumptions and interpretation of results. Despite these challenges, modeling yielded estimates and projections that public health officials used to make key decisions regarding response strategy and resources required. The impact of modeling during the Ebola response demonstrates the usefulness of modeling in future responses, particularly in the early stages and when data are scarce. Future modeling can be enhanced by planning ahead for data needs and data sharing, and by open communication among modelers, scientists, and others to ensure that modeling and its limitations are more clearly understood. The activities summarized in

  11. Free cortisol awakening responses are influenced by awakening time.

    PubMed

    Federenko, Ilona; Wüst, Stefan; Hellhammer, Dirk H; Dechoux, Ralph; Kumsta, Robert; Kirschbaum, Clemens

    2004-02-01

    Psychobiological investigations on the hypothalamus-pituitary-adrenal (HPA) axis depend on markers that adequately describe the activity of this system. There is evidence that the free cortisol response to awakening, proposed as a marker for the HPA axis, can be influenced by time of awakening. To further investigate this possible confounder, 24 shift working nurses and 31 female students on a regular sleep-wake cycle collected saliva samples 0, 30, 45 and 60 minutes after awakening. Nurses were investigated on the first and second day of their early (awakening: 04:00-05:30 h), late (awakening: 06:00-09:00 h), and night shift (awakening: 11:00-14:00 h), respectively. Students were studied after taking a short nap on two consecutive weekdays (awakening: 18:45-20:30 h). Mean cortisol levels after awakening increased significantly under all three shift conditions (p<0.01), but decreased in the student sample (p<.05). Within the three shift conditions, cortisol responses following waking in the early shift were more pronounced than in late (p<.01) and night shift (p<.05). The present study shows that in a sample with a large range of awakening times, an impact of this variable on the cortisol awakening response can be observed. The data furthermore strongly suggest that waking up per se is insufficient for adrenocortical stimulation. PMID:14604599

  12. Time-dependent response of dissipative electron systems

    SciTech Connect

    Tremblay, Jean Christophe; Krause, Pascal; Klamroth, Tillmann; Saalfrank, Peter

    2010-06-15

    We present a systematic study of the influence of energy and phase relaxation on dynamic polarizability simulations in the linear response regime. The nonperturbative approach is based on explicit electron dynamics using short laser pulses of low intensities. To include environmental effects on the property calculation, we use the time-dependent configuration-interaction method in its reduced density matrix formulation. Both energy dissipation and nonlocal pure dephasing are included. The explicit treatment of time-resolved electron dynamics gives access to the phase shift between the electric field and the induced dipole moment, which can be used to define a useful uncertainty measure for the dynamic polarizability. The nonperturbative treatment is compared to perturbation theory expressions, as applied to a simple model system, the rigid H{sub 2} molecule. It is shown that both approaches are equivalent for low field intensities, but the time-dependent treatment provides complementary information on the phase of the induced dipole moment, which allows for the definition of an uncertainty associated with the computation of the dynamic polarizability in the linear response regime.

  13. Dual-frequency liquid crystal gels with submillisecond response time

    NASA Astrophysics Data System (ADS)

    Fan, Yun-Hsing; Ren, Hongwen; Liang, Xiao; Lin, Yi-Hsin; Wu, Shin-Tson

    2004-09-01

    Two types of gels using dual-frequency liquid crystal are demonstrated. The one using a homogeneous cell shows anisotropic scattering behavior while the other prepared using a cell without polyimide alignment layers exhibits isotropic scattering properties. Both liquid crystal gels are highly transparent in the voltage-off state. Light scattering occurs when a high frequency voltage is applied. The isotropic gel exhibits a high contrast ratio and submillisecond response time. Potential applications of these gels for switchable polarizer, telecom optical switch, and reflective displays are emphasized.

  14. Time domain response of electrical ceramics -- Micro to megaseconds

    SciTech Connect

    Modine, F.A.

    1997-11-01

    The electrical properties of ceramics can be measured in either the time domain or in the frequency domain. But for electrically nonlinear ceramics such as varistors, time-domain measurements provide insights that are different and more relevant to material performance as well as being more physically incisive. This article focuses specifically on the electrical properties of ZnO varistors, but much of it is of relevance for other materials, in particular those materials with grain-boundary barriers and disordered ceramics or glasses. The interpretation of electrical measurements in the time domain is profoundly influenced by such practical matters as source impedance and waveform characteristics. Experimental results are presented for both high and low source impedance relative to that of a test varistor, and the different in experimental difficulty and ease of interpretation is described. Time-domain measurements of capacitance and of the inductive response of varistors to large, fast electrical pulses are presented and their implications for varistor theory are given. Experimental evidence is given of short- and long-term memory in varistors. These memory phenomena are ascribed respectively to the life time of holes that become trapped in barriers and to polarization currents originating from deep electron traps. Polarization current measurements are presented for a wide range of time and temperature. The power-law time dependence and universal behavior of these currents is discussed. The exponent that describes the power law behavior is seen to change with temperature, and the change is interpreted as a double transition from diffusive to dispersive transport that originates with current from two different electron traps.

  15. Time domain responses of a prestressed beam and prestress identification

    NASA Astrophysics Data System (ADS)

    Law, S. S.; Lu, Z. R.

    2005-12-01

    The time-domain response of a prestressed Euler-Bernoulli beam under external excitation is studied based on modal superposition. The prestress force is then identified in the time domain by a system identification approach and Tikhonov regularization technique is used to provide bounds to the ill-conditioned results in the identified problem. Both measured displacements and strains are used. The noise effect is improved using the orthogonal polynomial function, and cases with either sinusoidal or impulsive excitations are illustrated to give very good results from the lower three measured modes and data obtained from three measurement points. Work in this paper demonstrates the feasibility of indirectly identifying the prestress force in a beam.

  16. Fast-Response-Time Shape-Memory-Effect Foam Actuators

    NASA Technical Reports Server (NTRS)

    Jardine, Peter

    2010-01-01

    Bulk shape memory alloys, such as Nitinol or CuAlZn, display strong recovery forces undergoing a phase transformation after being strained in their martensitic state. These recovery forces are used for actuation. As the phase transformation is thermally driven, the response time of the actuation can be slow, as the heat must be passively inserted or removed from the alloy. Shape memory alloy TiNi torque tubes have been investigated for at least 20 years and have demonstrated high actuation forces [3,000 in.-lb (approximately equal to 340 N-m) torques] and are very lightweight. However, they are not easy to attach to existing structures. Adhesives will fail in shear at low-torque loads and the TiNi is not weldable, so that mechanical crimp fits have been generally used. These are not reliable, especially in vibratory environments. The TiNi is also slow to heat up, as it can only be heated indirectly using heater and cooling must be done passively. This has restricted their use to on-off actuators where cycle times of approximately one minute is acceptable. Self-propagating high-temperature synthesis (SHS) has been used in the past to make porous TiNi metal foams. Shape Change Technologies has been able to train SHS derived TiNi to exhibit the shape memory effect. As it is an open-celled material, fast response times were observed when the material was heated using hot and cold fluids. A methodology was developed to make the open-celled porous TiNi foams as a tube with integrated hexagonal ends, which then becomes a torsional actuator with fast response times. Under processing developed independently, researchers were able to verify torques of 84 in.-lb (approximately equal to 9.5 Nm) using an actuator weighing 1.3 oz (approximately equal to 37 g) with very fast (less than 1/16th of a second) initial response times when hot and cold fluids were used to facilitate heat transfer. Integrated structural connections were added as part of the net shape process, eliminating

  17. Real-time seismic monitoring of the integrated cape girardeau bridge array and recorded earthquake response

    USGS Publications Warehouse

    Celebi, M.

    2006-01-01

    This paper introduces the state of the art, real-time and broad-band seismic monitoring network implemented for the 1206 m [3956 ft] long, cable-stayed Bill Emerson Memorial Bridge in Cape Girardeau (MO), a new Mississippi River crossing, approximately 80 km from the epicentral region of the 1811-1812 New Madrid earthquakes. The bridge was designed for a strong earthquake (magnitude 7.5 or greater) during the design life of the bridge. The monitoring network comprises a total of 84 channels of accelerometers deployed on the superstructure, pier foundations and at surface and downhole free-field arrays of the bridge. The paper also presents the high quality response data obtained from the network. Such data is aimed to be used by the owner, researchers and engineers to assess the performance of the bridge, to check design parameters, including the comparison of dynamic characteristics with actual response, and to better design future similar bridges. Preliminary analyses of ambient and low amplitude small earthquake data reveal specific response characteristics of the bridge and the free-field. There is evidence of coherent tower, cable, deck interaction that sometimes results in amplified ambient motions. Motions at the lowest tri-axial downhole accelerometers on both MO and IL sides are practically free from any feedback from the bridge. Motions at the mid-level and surface downhole accelerometers are influenced significantly by feedback due to amplified ambient motions of the bridge. Copyright ASCE 2006.

  18. Time-dependent mechanical response of HDPE geomembranes

    SciTech Connect

    Merry, S.M.; Bray, J.D.

    1997-01-01

    Geomembranes are used extensively in the construction of base liners and cover systems for both hazardous and municipal waste-containment facilities. Characterization of the long-term mechanical response of geomembranes used in waste-containment facilities is crucial to designing base liner and over systems that perform satisfactorily. To investigate the long-term mechanical response, strain-controlled multiaxial tension testing was performed over a fourfold variation of strain rate using a newly developed multiaxial tension-test apparatus capable of performing constant strain rate and constant stress creep tests. This device subjects a geomembrane specimen to multiaxial stress states and allows for the development of strain conditions that vary from plane strain at the clamped edges to balanced biaxial at the center. Results from testing high-density polyethylene (HDPE) specimens indicate that the secant modulus and strength decreases considerably at strain rates appropriate for long-term field applications. The strength of HDPE measured at a typical laboratory strain rate of 1% per minute can be more than twice the strength predicted at a strain rate of 1E-6% per minute, which may be representative of field performance for a typical 30-year design life. A hyperbolic model and the Singh-Mitchell creep model (which was originally formulated for soils) are shown to capture the time-dependent mechanical response of HDPE well.

  19. Response time correlations for platinum resistance thermometers in flowing fluids

    NASA Technical Reports Server (NTRS)

    Pandey, D. K.; Ash, R. L.

    1985-01-01

    The thermal response of two types of Platinum Resistance Thermometers (PRT's), which are being considered for use in the National Transonic Wind Tunnel Facility, were studied. Response time correlations for each PRT, in flowing water, oil and air, were established separately. A universal correlation, tau WOA = 2.0 + 1264, 9/h, for a Hy-Cal Sensor (with a reference resistance of 100 ohm) within an error of 20% was established while the universal correlation for the Rosemount Sensor (with a reference resistance of 1000 ohm), tau OA = 0.122 + 1105.6/h, was found with a maximum percentage error of 30%. The correlation for the Rosemount Sensor was based on air and oil data only which is certainly not sufficient to make a correlation applicable to every condition. Therefore, the correlation needs more data to be gathered in different fluids. Also, it is necessary to state that the calculation of the parameter, h, was based on the available heat transfer correlations, whose accuracies are already reported in literature uncertain within 20-30%. Therefore, the universal response constant correlations established here for the Hy-Cal and Rosemount sensors are consistent with the uncertainty in the input data and are recommended for future use in flowing liquids and gases.

  20. Time domain responses of hydraulic bushing with two flow passages

    NASA Astrophysics Data System (ADS)

    Chai, Tan; Dreyer, Jason T.; Singh, Rajendra

    2014-02-01

    Hydraulic bushings are commonly employed in vehicle suspension and body sub-frame systems to control motion, vibration, and structure-borne noise. Since literature on this topic is sparse, a controlled bushing prototype which accommodates a combination of long and short flow passages and flow restriction elements is first designed, constructed and instrumented. Step-up and step-down responses of several typical fluid-filled bushing configurations are measured along with steady harmonic time histories of transmitted force and internal pressures. To analyze the experimental results and gain physical insights into the hydraulic bushing system, lumped system models of bushings with different design features are developed, and analytical expressions of transmitted force and internal pressure responses are derived by using the convolution method. Parametric studies are also conducted to examine the effect of hydraulic element parameters. System parameters are successfully estimated for both harmonic and step responses using theory and measurements, and the dynamic force measurements are analyzed using analytical predictions. Finally, some nonlinearities of the system are also observed, and the fluid resistance of flow passage is found to be the most nonlinear element.

  1. Evaluating Cognitive Theory: A Joint Modeling Approach Using Responses and Response Times

    ERIC Educational Resources Information Center

    Klein Entink, Rinke H.; Kuhn, Jorg-Tobias; Hornke, Lutz F.; Fox, Jean-Paul

    2009-01-01

    In current psychological research, the analysis of data from computer-based assessments or experiments is often confined to accuracy scores. Response times, although being an important source of additional information, are either neglected or analyzed separately. In this article, a new model is developed that allows the simultaneous analysis of…

  2. Ampoule failure sensor time response testing: Experiment 1

    NASA Technical Reports Server (NTRS)

    Johnson, M. L.; Watring, D. A.

    1994-01-01

    The response time of an ampoule failure sensor exposed to a liquid or vapor gallium-arsenide (GaAs) is investigated. The experimental configuration represents the sample/ampoule cartridge assembly used in NASA's Crystal Growth Furnace (CGF). The sensor is a chemical fuse made from a metal with which the semiconductor material reacts more rapidly than it does with the containing cartridge. For the III-IV compound of GaAs, a platinum metal was chosen based on the reaction of platinum and arsenic at elevated temperatures which forms a low melting eutectic. Ampoule failure is indicated by a step change in resistance of the failure sensor on the order of megohms. The sensors will increase the safety of crystal growth experiments by providing an indication that an ampoule has failed. Experimental results indicate that the response times (after a known ampoule failure) for the 0.003 and 0.010 inch ampoule failure sensors are 2.4 and 3.6 minutes, respectively. This ampoule failure sensor will be utilized in the CGF during the second United States Microgravity Laboratory Mission (USML-2) and is the subject of a NASA patent application.

  3. Role of Estrogen Response Element in the Human Prolactin Gene: Transcriptional Response and Timing

    PubMed Central

    McNamara, Anne V.; Adamson, Antony D.; Dunham, Lee S. S.; Semprini, Sabrina; Spiller, David G.; McNeilly, Alan S.; Mullins, John J.

    2016-01-01

    The use of bacterial artificial chromosome (BAC) reporter constructs in molecular physiology enables the inclusion of large sections of flanking DNA, likely to contain regulatory elements and enhancers regions that contribute to the transcriptional output of a gene. Using BAC recombineering, we have manipulated a 160-kb human prolactin luciferase (hPRL-Luc) BAC construct and mutated the previously defined proximal estrogen response element (ERE) located −1189 bp relative to the transcription start site, to assess its involvement in the estrogen responsiveness of the entire hPRL locus. We found that GH3 cell lines stably expressing Luc under control of the ERE-mutated hPRL promoter (ERE-Mut) displayed a dramatically reduced transcriptional response to 17β-estradiol (E2) treatment compared with cells expressing Luc from the wild-type (WT) ERE hPRL-Luc promoter (ERE-WT). The −1189 ERE controls not only the response to E2 treatment but also the acute transcriptional response to TNFα, which was abolished in ERE-Mut cells. ERE-WT cells displayed a biphasic transcriptional response after TNFα treatment, the acute phase of which was blocked after treatment with the estrogen receptor antagonist 4-hydroxy-tamoxifen. Unexpectedly, we show the oscillatory characteristics of hPRL promoter activity in individual living cells were unaffected by disruption of this crucial response element, real-time bioluminescence imaging showed that transcription cycles were maintained, with similar cycle lengths, in ERE-WT and ERE-Mut cells. These data suggest the −1189 ERE is the dominant response element involved in the hPRL transcriptional response to both E2 and TNFα and, crucially, that cycles of hPRL promoter activity are independent of estrogen receptor binding. PMID:26691151

  4. Driving time modulates accommodative response and intraocular pressure.

    PubMed

    Vera, Jesús; Diaz-Piedra, Carolina; Jiménez, Raimundo; Morales, José M; Catena, Andrés; Cardenas, David; Di Stasi, Leandro L

    2016-10-01

    Driving is a task mainly reliant on the visual system. Most of the time, while driving, our eyes are constantly focusing and refocusing between the road and the dashboard or near and far traffic. Thus, prolonged driving time should produce visual fatigue. Here, for the first time, we investigated the effects of driving time, a common inducer of driver fatigue, on two ocular parameters: the accommodative response (AR) and the intraocular pressure (IOP). A pre/post-test design has been used to assess the impact of driving time on both indices. Twelve participants (out of 17 recruited) completed the study (5 women, 24.42±2.84years old). The participants were healthy and active drivers with no visual impairment or pathology. They drove for 2h in a virtual driving environment. We assessed AR and IOP before and after the driving session, and also collected subjective measures of arousal and fatigue. We found that IOP and AR decreased (i.e., the accommodative lag increased) after the driving session (p=0.03 and p<0.001, respectively). Moreover, the nearest distances tested (20cm, 25cm, and 33cm) induced the highest decreases in AR (corrected p-values<0.05). Consistent with these findings, the subjective levels of arousal decreased and levels of fatigue increased after the driving session (all p-values<0.001). These results represent an innovative step towards an objective, valid, and reliable assessment of fatigue-impaired driving based on visual fatigue signs. PMID:27235337

  5. Designing for time-dependent material response in spacecraft structures

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.; Oleksuk, Lynda L. S.; Bowles, D. E.

    1992-01-01

    To study the influence on overall deformations of the time-dependent constitutive properties of fiber-reinforced polymeric matrix composite materials being considered for use in orbiting precision segmented reflectors, simple sandwich beam models are developed. The beam models include layers representing the face sheets, the core, and the adhesive bonding of the face sheets to the core. A three-layer model lumps the adhesive layers with the face sheets or core, while a five-layer model considers the adhesive layers explicitly. The deformation response of the three-layer and five-layer sandwich beam models to a midspan point load is studied. This elementary loading leads to a simple analysis, and it is easy to create this loading in the laboratory. Using the correspondence principle of viscoelasticity, the models representing the elastic behavior of the two beams are transformed into time-dependent models. Representative cases of time-dependent material behavior for the facesheet material, the core material, and the adhesive are used to evaluate the influence of these constituents being time-dependent on the deformations of the beam. As an example of the results presented, if it assumed that, as a worst case, the polymer-dominated shear properties of the core behave as a Maxwell fluid such that under constant shear stress the shear strain increases by a factor of 10 in 20 years, then it is shown that the beam deflection increases by a factor of 1.4 during that time. In addition to quantitative conclusions, several assumptions are discussed which simplify the analyses for use with more complicated material models. Finally, it is shown that the simpler three-layer model suffices in many situations.

  6. A real-time emergency response workstation using a 3-D numerical model initialized with sodar

    SciTech Connect

    Lawver, B.S.; Sullivan, T.J.; Baskett, R.L.

    1993-01-28

    Many emergency response dispersion modeling systems provide simple Gaussian models driven by single meteorological tower inputs to estimate the downwind consequences from accidental spills or stack releases. Complex meteorological or terrain settings demand more sophisticated resolution of the three-dimensional structure of the atmosphere to reliably calculate plume dispersion. Mountain valleys and sea breeze flows are two common examples of such settings. To address these complexities, the authors have implemented the three-dimensional diagnostic MATHEW mass-adjusted wind field and ADPIC particle-in-cell dispersion models on a workstation for use in real-time emergency response modeling. MATHEW/ADPIC have shown their utility in a variety of complex settings over the last 15 years within the Department of Energy`s Atmospheric Release Advisory Capability (ARAC) project. The models are initialized using an array of surface wind measurements from meteorological towers coupled with vertical profiles from an acoustic sounder (sodar). The workstation automatically acquires the meteorological data every 15 minutes. A source term is generated using either defaults or a real-time stack monitor. Model outputs include contoured isopleths displayed on site geography or plume densities shown over 3-D color shaded terrain. The models are automatically updated every 15 minutes to provide the emergency response manager with a continuous display of potentially hazardous ground-level conditions if an actual release were to occur. Model run time is typically less than 2 minutes on 6 megaflop ({approximately}30 MIPS) workstations. Data acquisition, limited by dial-up modem communications, requires 3 to 5 minutes.

  7. Comment on 'Shang S. 2012. Calculating actual crop evapotranspiration under soil water stress conditions with appropriate numerical methods and time step. Hydrological Processes 26: 3338-3343. DOI: 10.1002/hyp.8405'

    NASA Technical Reports Server (NTRS)

    Yatheendradas, Soni; Narapusetty, Balachandrudu; Peters-Lidard, Christa; Funk, Christopher; Verdin, James

    2014-01-01

    A previous study analyzed errors in the numerical calculation of actual crop evapotranspiration (ET(sub a)) under soil water stress. Assuming no irrigation or precipitation, it constructed equations for ET(sub a) over limited soil-water ranges in a root zone drying out due to evapotranspiration. It then used a single crop-soil composite to provide recommendations about the appropriate usage of numerical methods under different values of the time step and the maximum crop evapotranspiration (ET(sub c)). This comment reformulates those ET(sub a) equations for applicability over the full range of soil water values, revealing a dependence of the relative error in numerical ET(sub a) on the initial soil water that was not seen in the previous study. It is shown that the recommendations based on a single crop-soil composite can be invalid for other crop-soil composites. Finally, a consideration of the numerical error in the time-cumulative value of ET(sub a) is discussed besides the existing consideration of that error over individual time steps as done in the previous study. This cumulative ET(sub a) is more relevant to the final crop yield.

  8. Field response and switching times in biaxial nematics

    NASA Astrophysics Data System (ADS)

    Berardi, Roberto; Muccioli, Luca; Zannoni, Claudio

    2008-01-01

    We study by means of virtual molecular dynamics computer experiments the response of a bulk biaxial nematic to an applied external field and, in particular, the relative speed of reorientation of the principal director axis and of the secondary one, typical of these new materials, upon a π /2 field switch. We perform the simulations setting up and integrating the equations of motion for biaxial Gay-Berne particles using quaternions and a suitable time reversible symplectic integrator. We find that switching of the secondary axis is up to an order of magnitude faster than that of the principal axis, and that under fields above a certain strength a reorganization of local domains, temporarily disrupting the nematic and biaxial ordering, rather than a collective concerted reorientation occurs.

  9. Viewer response to time-varying video quality

    NASA Astrophysics Data System (ADS)

    Pearson, Don E.

    1998-07-01

    Over the past several years we have investigated viewer response to temporal fluctuations in the quality of digital television pictures, which occur when video is coded into relatively low bit rates. Three phenomena of interest have been identified: (1) a forgiveness effect, (2) a recency effect, and (3) a negative-peak (duration-neglect); these are described and discussed in the paper. In collaboration with our partners in European projects MOSAIC and TAPESTRIES, we have developed a three-stage method of measuring time-variant quality, which has been accepted by the ITU-R. The first stage is a Single Stimulus Continuous Quality Evaluation (SSCQE) of instantaneous quality; the second a calibration stage to link SSCQE with conventional DSCQS, and the third stage a numerical procedure for relating continuous and overall quality. Some of the factors we have identified as being important in producing good overall quality judgements have relevance to the design of optimal coding strategies for digital television.

  10. Word Association in L1 and L2: An Exploratory Study of Response Types, Response Times, and Interlingual Mediation

    ERIC Educational Resources Information Center

    Fitzpatrick, Tess; Izura, Cristina

    2011-01-01

    Word association responses in first-language (L1) Spanish and second-language (L2) English were investigated by means of response latencies and types of associative response produced. The primary aims were to establish whether (a) some response types are produced more often or faster than others, (b) participants' L2 response time profiles mirror…

  11. On the time course of rapid and repeatable response induction.

    PubMed

    Jarmolowicz, David P; Hudnall, Jennifer L; Darden, Alexandria C; Lemley, Shea M; Sofis, Michael J

    2015-11-01

    As reinforcers are delivered for a particular response, that response increases. Other similar responses also increase, with the extent to which this increase is seen being positively related to the similarity between the responses. This process, called induction, is pronounced during initial response acquisition, and dissipates as the target response is established. The present experiment examined this process in a paradigm wherein responses to one of five nose poke receptacles results in reinforcement for six sessions in each condition and the target location changes between conditions. Consistent patterns of induction were seen across conditions, with patterns of induction dissipating within each condition.

  12. Real-time GPS Strategies for Rapid Response Applications

    NASA Astrophysics Data System (ADS)

    Johanson, I. A.; Dreger, D. S.

    2012-12-01

    High-rate, low-latency GPS data can make valuable contribution to both Earthquake Early Warning (EEW) and Rapid Response (RR) applications. While GPS will make is largest contribution to EEW in high magnitude earthquakes, it can provide valuable information to RR products for many more events, from moderate to high magnitude. In particular, static offsets from GPS provide information on the fault plane orientation and total slip in a finite slip inversion, which is used to produce Shakemap. Shakemap is a product that shows the estimated intensity of shaking around the epicentral area and is used by first responders to evaluate where damage is likely to have occurred. In this project, we investigate strategies for using GPS data for moderate earthquakes in California to produce estimates of static offsets and estimate a slip plane within minutes following an event. The 2007 M5.6 Alum Rock and 2004 M6.0 Parkfield earthquakes are used as test cases and the data is processed using Track and TrackRT. Multiple methods for measuring the static offsets from the displacement waveforms are tested, including differencing the pre- and post- earthquake median positions and a method involving pre- and post- earthquake line fitting. We also look into the effects of different types of starting geometry on the speed and accuracy of the non-linear fault plane determination process. We find that rapid post-processing with Track allows more robust static offset determination from these smaller earthquakes than real-time processing (as it exists today). Rapid post-processing can be finished and displacement waveforms made available within a couple minutes, well within the time threshold for other rapid products and providing essentially no delay to the final products. Nonetheless, this strategy still requires real-time transmission of data from the field to the lab so that it is available on demand following an event.

  13. Time-resolved diagnostics for concrete target response

    SciTech Connect

    Baum, D.W.; Kuklo, R.M.; Reaugh, J.E.; Simonson, S.C.

    1996-05-01

    In order to facilitate the design of advanced penetrating weapons for defeating land targets, the interaction of concrete with high-velocity penetrators needs to be better characterized. To aid in this effort, three new types of time-resolved diagnostics are being developed and have been used in two experiments and one demonstration: fiber optic arrays to localize penetrators in space and time, Fabry-Perot velocimetry to record the concrete particle velocity, which is related to the pressure, at specific locations within concrete targets, and micropower impulse radar to provide a non-intrusive measure of the penetrator position-time history in a target. The two experiments used the fiber optic array and the Fabry-Perot velocimeter to diagnose the response of concrete to penetration by a Viper shaped charge jet. The results were analyzed using the CALE continuum mechanics simulation program, for which a preliminary model of the material properties of concrete was developed. The fiber optic arrays recorded the bow shock at locations 6.4 and 16.9 cm from the front surfaces. The Fabry-Perot velocimeter measured a free-surface velocity of 0.13 km/s at a distance of 3 cm and obliquity 70{degree} from the jet, which was moving at an interface velocity of 4.0 km/s at a depth of 29 cm. These values imply a pressure of about 6.6 kbar at that location. The demonstration used micropower impulse radar with a pulse repetition frequency of 0.25 MHz and a cell size of 30 ps to detect and record the motion of a metal penetrator simulant moving inside a cylindrical concrete target.

  14. Interpreting response time effects in functional imaging studies

    PubMed Central

    Taylor, J.S.H.; Rastle, Kathleen; Davis, Matthew H.

    2014-01-01

    It has been suggested that differential neural activity in imaging studies is most informative if it is independent of response time (RT) differences. However, others view RT as a behavioural index of key cognitive processes, which is likely linked to underlying neural activity. Here, we reconcile these views using the effort and engagement framework developed by Taylor, Rastle, and Davis (2013) and data from the domain of reading aloud. We propose that differences in neural engagement should be independent of RT, whereas, differences in neural effort should co-vary with RT. We illustrate these different mechanisms using data from an fMRI study of neural activity during reading aloud of regular words, irregular words, and pseudowords. In line with our proposals, activation revealed by contrasts designed to tap differences in neural engagement (e.g., words are meaningful and therefore engage semantic representations more than pseudowords) survived correction for RT, whereas activation for contrasts designed to tap differences in neural effort (e.g., it is more difficult to generate the pronunciation of pseudowords than words) correlated with RT. However, even for contrasts designed to tap neural effort, activity remained after factoring out the RT–BOLD response correlation. This may reveal unpredicted differences in neural engagement (e.g., learning phonological forms for pseudowords > words) that could further the development of cognitive models of reading aloud. Our framework provides a theoretically well-grounded and easily implemented method for analysing and interpreting RT effects in neuroimaging studies of cognitive processes. PMID:24904992

  15. K+-selective nanospheres: maximising response range and minimising response time.

    PubMed

    Ruedas-Rama, Maria Jose; Hall, Elizabeth A H

    2006-12-01

    Cross-linked K(+) ion-selective copolymer nanospheres have been prepared by free-radical photo-initiated polymerization of n-butyl acrylate (nBA) with hexanedioldiacrylate (HDDA). Nanospheres (<200 nm) containing H(+)-chromoionophore (ETH 5294) and lipophilic salt (KTClPB) for H(+)-sensors, or ETH 5294, a K(+)-selective ionophore (valinomycin) and anionic sites for K(+)-sensors were compared, and the effect of varying the normalised concentrations for beta (R(T)(-)/L(T)) and gamma (C(m)(T)/L(T)) was studied. Experimental data were fitted to theoretical curves for the dynamic response range, based on the effect of changes in the concentration of these lipophilic sensing components incorporated into the spheres, and conditions identified for maximising the response range. A complex valinomycin-K(+) formation constant, log K(IL) = 13.13 +/- 2.22, was obtained in the nBA matrix, and from the calibration curves the apparent acid-dissociation equilibrium constant (pK(a) = 12.92 +/- 0.03) was extracted for the H(+)-sensing system, and the equilibrium exchange constant (pK(exch) = 6.16 +/- 0.03, at pH 7) calculated for the K(+)-sensing nanospheres. A basis for establishing optimum performance was identified, whereby response range and response time were balanced with maximum fluorescence yield. Parameters for achieving nanospheres with a response time <5 minutes, covering 2-3 orders of magnitude change in activity were identified, demanding nanospheres with radius <300 nm and beta(crit) approximately 0.6. An RSD(%) approximately 3% was obtained in a study of the reproducibility of the response of the proposed nanospheres, and selectivity was also evaluated for a K(+)-selective nanosensor using several cations as interfering agents. In most cases, the fluorescent emission spectra showed no response to the cations tested, confirming the selectivity of nanospheres to potassium ion. The nanosensors were satisfactorily applied to the determination of K(+) in samples mimicking

  16. K+-selective nanospheres: maximising response range and minimising response time.

    PubMed

    Ruedas-Rama, Maria Jose; Hall, Elizabeth A H

    2006-12-01

    Cross-linked K(+) ion-selective copolymer nanospheres have been prepared by free-radical photo-initiated polymerization of n-butyl acrylate (nBA) with hexanedioldiacrylate (HDDA). Nanospheres (<200 nm) containing H(+)-chromoionophore (ETH 5294) and lipophilic salt (KTClPB) for H(+)-sensors, or ETH 5294, a K(+)-selective ionophore (valinomycin) and anionic sites for K(+)-sensors were compared, and the effect of varying the normalised concentrations for beta (R(T)(-)/L(T)) and gamma (C(m)(T)/L(T)) was studied. Experimental data were fitted to theoretical curves for the dynamic response range, based on the effect of changes in the concentration of these lipophilic sensing components incorporated into the spheres, and conditions identified for maximising the response range. A complex valinomycin-K(+) formation constant, log K(IL) = 13.13 +/- 2.22, was obtained in the nBA matrix, and from the calibration curves the apparent acid-dissociation equilibrium constant (pK(a) = 12.92 +/- 0.03) was extracted for the H(+)-sensing system, and the equilibrium exchange constant (pK(exch) = 6.16 +/- 0.03, at pH 7) calculated for the K(+)-sensing nanospheres. A basis for establishing optimum performance was identified, whereby response range and response time were balanced with maximum fluorescence yield. Parameters for achieving nanospheres with a response time <5 minutes, covering 2-3 orders of magnitude change in activity were identified, demanding nanospheres with radius <300 nm and beta(crit) approximately 0.6. An RSD(%) approximately 3% was obtained in a study of the reproducibility of the response of the proposed nanospheres, and selectivity was also evaluated for a K(+)-selective nanosensor using several cations as interfering agents. In most cases, the fluorescent emission spectra showed no response to the cations tested, confirming the selectivity of nanospheres to potassium ion. The nanosensors were satisfactorily applied to the determination of K(+) in samples mimicking

  17. Teenagers' Perceived and Actual Probabilities of Pregnancy.

    ERIC Educational Resources Information Center

    Namerow, Pearila Brickner; And Others

    1987-01-01

    Explored adolescent females' (N=425) actual and perceived probabilities of pregnancy. Subjects estimated their likelihood of becoming pregnant the last time they had intercourse, and indicated the dates of last intercourse and last menstrual period. Found that the distributions of perceived probability of pregnancy were nearly identical for both…

  18. Timing of plant immune responses by a central circadian regulator.

    PubMed

    Wang, Wei; Barnaby, Jinyoung Yang; Tada, Yasuomi; Li, Hairi; Tör, Mahmut; Caldelari, Daniela; Lee, Dae-un; Fu, Xiang-Dong; Dong, Xinnian

    2011-02-01

    The principal immune mechanism against biotrophic pathogens in plants is the resistance (R)-gene-mediated defence. It was proposed to share components with the broad-spectrum basal defence machinery. However, the underlying molecular mechanism is largely unknown. Here we report the identification of novel genes involved in R-gene-mediated resistance against downy mildew in Arabidopsis and their regulatory control by the circadian regulator, CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1). Numerical clustering based on phenotypes of these gene mutants revealed that programmed cell death (PCD) is the major contributor to resistance. Mutants compromised in the R-gene-mediated PCD were also defective in basal resistance, establishing an interconnection between these two distinct defence mechanisms. Surprisingly, we found that these new defence genes are under circadian control by CCA1, allowing plants to 'anticipate' infection at dawn when the pathogen normally disperses the spores and time immune responses according to the perception of different pathogenic signals upon infection. Temporal control of the defence genes by CCA1 differentiates their involvement in basal and R-gene-mediated defence. Our study has revealed a key functional link between the circadian clock and plant immunity.

  19. Real-time Responsiveness for Ethics Oversight During Disaster Research.

    PubMed

    Eckenwiler, Lisa; Pringle, John; Boulanger, Renaud; Hunt, Matthew

    2015-11-01

    Disaster research has grown in scope and frequency. Research in the wake of disasters and during humanitarian crises--particularly in resource-poor settings--is likely to raise profound and unique ethical challenges for local communities, crisis responders, researchers, and research ethics committees (RECs). Given the ethical challenges, many have questioned how best to provide research ethics review and oversight. We contribute to the conversation concerning how best to ensure appropriate ethical oversight in disaster research and argue that ethical disaster research requires of researchers and RECs a particular sort of ongoing, critical engagement which may not be warranted in less exceptional research. We present two cases that typify the concerns disaster researchers and RECs may confront, and elaborate upon what this ongoing engagement might look like--how it might be conceptualized and utilized--using the concept of real-time responsiveness (RTR). The central aim of RTR, understood here as both an ethical ideal and practice, is to lessen the potential for research conducted in the wake of disasters to create, perpetuate, or exacerbate vulnerabilities and contribute to injustices suffered by disaster-affected populations. Well cultivated and deployed, we believe that RTR may enhance the moral capacities of researchers and REC members, and RECs as institutions where moral agency is nurtured and sustained.

  20. Real-time Responsiveness for Ethics Oversight During Disaster Research.

    PubMed

    Eckenwiler, Lisa; Pringle, John; Boulanger, Renaud; Hunt, Matthew

    2015-11-01

    Disaster research has grown in scope and frequency. Research in the wake of disasters and during humanitarian crises--particularly in resource-poor settings--is likely to raise profound and unique ethical challenges for local communities, crisis responders, researchers, and research ethics committees (RECs). Given the ethical challenges, many have questioned how best to provide research ethics review and oversight. We contribute to the conversation concerning how best to ensure appropriate ethical oversight in disaster research and argue that ethical disaster research requires of researchers and RECs a particular sort of ongoing, critical engagement which may not be warranted in less exceptional research. We present two cases that typify the concerns disaster researchers and RECs may confront, and elaborate upon what this ongoing engagement might look like--how it might be conceptualized and utilized--using the concept of real-time responsiveness (RTR). The central aim of RTR, understood here as both an ethical ideal and practice, is to lessen the potential for research conducted in the wake of disasters to create, perpetuate, or exacerbate vulnerabilities and contribute to injustices suffered by disaster-affected populations. Well cultivated and deployed, we believe that RTR may enhance the moral capacities of researchers and REC members, and RECs as institutions where moral agency is nurtured and sustained. PMID:26481207

  1. Realizing actual feedback control of complex network

    NASA Astrophysics Data System (ADS)

    Tu, Chengyi; Cheng, Yuhua

    2014-06-01

    In this paper, we present the concept of feedbackability and how to identify the Minimum Feedbackability Set of an arbitrary complex directed network. Furthermore, we design an estimator and a feedback controller accessing one MFS to realize actual feedback control, i.e. control the system to our desired state according to the estimated system internal state from the output of estimator. Last but not least, we perform numerical simulations of a small linear time-invariant dynamics network and a real simple food network to verify the theoretical results. The framework presented here could make an arbitrary complex directed network realize actual feedback control and deepen our understanding of complex systems.

  2. Structural Equation Model Approach to the Use of Response Times for Improving Estimation in Item Response Models

    ERIC Educational Resources Information Center

    Sen, Rohini

    2012-01-01

    In the last five decades, research on the uses of response time has extended into the field of psychometrics (Schnikpe & Scrams, 1999; van der Linden, 2006; van der Linden, 2007), where interest has centered around the usefulness of response time information in item calibration and person measurement within an item response theory. framework.…

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

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Guo, Fanmin

    2008-01-01

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

  4. Joint Modeling of Ability and Differential Speed Using Responses and Response Times.

    PubMed

    Fox, Jean-Paul; Marianti, Sukaesi

    2016-01-01

    With computerized testing, it is possible to record both the responses of test takers to test questions (i.e., items) and the amount of time spent by a test taker in responding to each question. Various models have been proposed that take into account both test-taker ability and working speed, with the many models assuming a constant working speed throughout the test. The constant working speed assumption may be inappropriate for various reasons. For example, a test taker may need to adjust the pace due to time mismanagement, or a test taker who started out working too fast may reduce the working speed to improve accuracy. A model is proposed here that allows for variable working speed. An illustration of the model using the Amsterdam Chess Test data is provided. PMID:27269482

  5. Time Evolution of Climate Response to Supervolcano Eruption

    NASA Astrophysics Data System (ADS)

    Stenchikov, G. L.

    2011-12-01

    A supervolcano could inject into the stratosphere enormous amount of SO2, in comparison with the recent historic eruptions, and therefore it is expected to produce strong reduction of the surface air temperature globally. However the climate response to stratospheric super-injections of sulfur-containing gases might not scale linearly with respect to the effects of moderate eruptions of the historic period. Here we find that, counter-intuitively, very large volcanic eruptions might cause climate warming, at least for a prolonged initial period after an eruption. Supervolcano eruptions like the Toba eruption 75,000 years ago have injected into the atmosphere hundreds of times more SO2 than the largest volcanic eruptions of the 20th century. The huge mass of sulfur from a Toba-size eruption could potentially produce a sulfate aerosol layer with optical depth of more than 40. However, the gas-to-particle conversion process might be effectively slowed down because SO2 and an initially formed relatively thin aerosol layer will absorb and reflect UV radiation, reducing actinic fluxes and OH production to almost zero within and below the SO2 layer. Therefore SO2 would not be quickly converted to sulfate aerosols, but would stay in the stratosphere for years. Because SO2, like ozone, is a strong greenhouse gas it would cause significant IR warming for an extended period until it will be converted to sulfate aerosols or removed. We have simulated Toba eruption using the NASA GISS ModelE, and find that coupled climate model results and available proxy data support this hypothesis.

  6. Modeling Individual Differences in Response Time and Accuracy in Numeracy

    PubMed Central

    Ratcliff, Roger; Thompson, Clarissa A.; McKoon, Gail

    2015-01-01

    In the study of numeracy, some hypotheses have been based on response time (RT) as a dependent variable and some on accuracy, and considerable controversy has arisen about the presence or absence of correlations between RT and accuracy, between RT or accuracy and individual differences like IQ and math ability, and between various numeracy tasks. In this article, we show that an integration of the two dependent variables is required, which we accomplish with a theory-based model of decision making. We report data from four tasks: numerosity discrimination, number discrimination, memory for two-digit numbers, and memory for three-digit numbers. Accuracy correlated across tasks, as did RTs. However, the negative correlations that might be expected between RT and accuracy were not obtained; if a subject was accurate, it did not mean that they were fast (and vice versa). When the diffusion decision-making model was applied to the data (Ratcliff, 1978), we found significant correlations across the tasks between the quality of the numeracy information (drift rate) driving the decision process and between the speed/ accuracy criterion settings, suggesting that similar numeracy skills and similar speed-accuracy settings are involved in the four tasks. In the model, accuracy is related to drift rate and RT is related to speed-accuracy criteria, but drift rate and criteria are not related to each other across subjects. This provides a theoretical basis for understanding why negative correlations were not obtained between accuracy and RT. We also manipulated criteria by instructing subjects to maximize either speed or accuracy, but still found correlations between the criteria settings between and within tasks, suggesting that the settings may represent an individual trait that can be modulated but not equated across subjects. Our results demonstrate that a decision-making model may provide a way to reconcile inconsistent and sometimes contradictory results in numeracy

  7. Assessing the Value of Regulation Resources Based on Their Time Response Characteristics

    SciTech Connect

    Makarov, Yuri V.; Lu, Shuai; Ma, Jian; Nguyen, Tony B.

    2008-06-01

    Fast responsive regulation resources are potentially more valuable as a power system regulation resource (more efficient) because they allow applying controls at the exact moment and in the exact amount as needed. Faster control is desirable because it facilitates more reliable compliance with the NERC Control Performance Standards at relatively lesser regulation capacity procurements. The current California ISO practices and markets do not provide a differentiation among the regulation resources based on their speed of response (with the exception of some minimum ramping capabilities). Some demand response technologies, including some generation and energy storage resources, can provide quicker control actions. California ISO practices and markets could be updated to welcome more fast regulation resources into the California ISO service area. The project work reported in this work was pursuing the following objectives: • Develop methodology to assess the relative value of generation resources used for regulation and load following California ISO functions • This assessment should be done based on physical characteristics including the ability to quickly change their output following California ISO signals • Evaluate what power is worth on different time scales • Analyze the benefits of new regulation resources to provide effective compliance with the mandatory NERC Control Performance Standards • Evaluate impacts of the newly proposed BAAL and FRR standards on the potential value of fast regulation and distributed regulation resources • Develop a scope for the follow-up projects to pave a road for the new efficient types of balancing resources in California. The work included the following studies: • Analysis of California ISO regulating units characteristics • California ISO automatic generation system (AGC) analysis • California ISO regulation procurement and market analysis • Fast regulation efficiency analysis • Projection of the

  8. Modulation of Response Timing in ADHD, Effects of Reinforcement Valence and Magnitude

    ERIC Educational Resources Information Center

    Luman, Marjolein; Oosterlaan, Jaap; Sergeant, Joseph A.

    2008-01-01

    The present study investigated the impact of reinforcement valence and magnitude on response timing in children with ADHD. Children were required to estimate a 1-s interval, and both the median response time (response tendency) and the intrasubject-variability (response stability) were investigated. In addition, heart rate and skin conductance…

  9. The Influence of Different Response Consequences on Children's Preference for Time-Out

    ERIC Educational Resources Information Center

    Willoughby, R. H.

    1970-01-01

    Time-out from positive reinforcement was found to have a suppressive effect when the response alternative was reinforced with the same frequency as the punished response. When the response alternative was a response for which positive reinforcement had been withdrawn, time-out was significantly preferred. (MH)

  10. Linguistic Theory and Actual Language.

    ERIC Educational Resources Information Center

    Segerdahl, Par

    1995-01-01

    Examines Noam Chomsky's (1957) discussion of "grammaticalness" and the role of linguistics in the "correct" way of speaking and writing. It is argued that the concern of linguistics with the tools of grammar has resulted in confusion, with the tools becoming mixed up with the actual language, thereby becoming the central element in a metaphysical…

  11. El Observatorio Gemini - Status actual

    NASA Astrophysics Data System (ADS)

    Levato, H.

    Se hace una breve descripción de la situación actual del Observatorio Gemini y de las últimas decisiones del Board para incrementar la eficiencia operativa. Se hace también una breve referencia al uso argentino del observatorio.

  12. Anticipating by Pigeons Depends on Local Statistical Information in a Serial Response Time Task

    ERIC Educational Resources Information Center

    Froehlich, Alyson L.; Herbranson, Walter T.; Loper, Julia D.; Wood, David M.; Shimp, Charles P.

    2004-01-01

    Pigeons responded in a serial response time task patterned after that of M. J. Nissen and P. Bullemer (1987) with humans. Experiment 1 produced global facilitation: Response times in repeating lists of locations were faster than when locations were random. Response time to a spatial location was also a function of both that location's 1st- and…

  13. Concerns about Appearing Prejudiced Get Under the Skin: Stress Responses to Interracial Contact in the Moment and across Time

    PubMed Central

    Trawalter, Sophie; Adam, Emma K.; Chase-Lansdale, P. Lindsay; Richeson, Jennifer A.

    2012-01-01

    Many White Americans are concerned about appearing prejudiced. How these concerns affect responses during actual interracial interactions, however, remains understudied. The present work examines stress responses to interracial contact—both in the moment, during interracial interactions (Study 1), and over time as individuals have repeated interracial contact (Study 2). Results of Study 1 revealed that concerns about appearing prejudiced were associated with heightened stress responses during interracial encounters (Study 1). White participants concerned about appearing prejudiced exhibited significant increases in cortisol “stress hormone” levels as well as increases in anxious behavior during interracial but not same-race contact. Participants relatively unconcerned about appearing prejudiced did not exhibit these stress responses. Study 2 examined stress responses to interracial contact over an entire academic year. Results revealed that White participants exhibited shifts in cortisol diurnal rhythms on days after interracial contact. Moreover, participants’ cortisol rhythms across the academic year, from fall to spring, were related to their concerns about appearing prejudiced and their interracial contact experiences. Taken together, these data offer the first evidence that chronic concerns about appearing prejudiced are related to short- and longer-term stress responses to interracial contact. Implications for life in diverse spaces are discussed. PMID:22711918

  14. Limited information estimation of the diffusion-based item response theory model for responses and response times.

    PubMed

    Ranger, Jochen; Kuhn, Jörg-Tobias; Szardenings, Carsten

    2016-05-01

    Psychological tests are usually analysed with item response models. Recently, some alternative measurement models have been proposed that were derived from cognitive process models developed in experimental psychology. These models consider the responses but also the response times of the test takers. Two such models are the Q-diffusion model and the D-diffusion model. Both models can be calibrated with the diffIRT package of the R statistical environment via marginal maximum likelihood (MML) estimation. In this manuscript, an alternative approach to model calibration is proposed. The approach is based on weighted least squares estimation and parallels the standard estimation approach in structural equation modelling. Estimates are determined by minimizing the discrepancy between the observed and the implied covariance matrix. The estimator is simple to implement, consistent, and asymptotically normally distributed. Least squares estimation also provides a test of model fit by comparing the observed and implied covariance matrix. The estimator and the test of model fit are evaluated in a simulation study. Although parameter recovery is good, the estimator is less efficient than the MML estimator.

  15. MCP PMT with high time response and linear output current for neutron time-of-flight detectors

    NASA Astrophysics Data System (ADS)

    Dolotov, A. S.; Konovalov, P. I.; Nurtdinov, R. I.

    2016-09-01

    A microchannel plate (MCP) photomultiplier tube (PMT) with a subnanosecond time response and a high linear output current has been developed. PMT is designed for detection of weak pulses of radiation in UV-, visible and nearer-IR ranges and can be used in neutron time-of-flight (nTOF) detectors in experiments on laser compression of thermonuclear fuel. The results of measurements of MCP PMT main parameters are presented: photocathode spectral sensitivity, gain, maximum linear output current, and time response.

  16. Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration

    NASA Technical Reports Server (NTRS)

    Hecox, K.; Squires, N.; Galambos, R.

    1975-01-01

    Short latency (under 10 msec) responses elicited by bursts of white noise were recorded from the scalps of human subjects. Response alterations produced by changes in the noise burst duration (on-time), inter-burst interval (off-time), and onset and offset shapes were analyzed. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise time but was unaffected by changes in fall time. Increases in stimulus duration, and therefore in loudness, resulted in a systematic increase in latency. This was probably due to response recovery processes, since the effect was eliminated with increases in stimulus off-time. The amplitude of wave V was insensitive to changes in signal rise and fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It was concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

  17. Timing and Tuning for Familiarity of Cortical Responses to Faces

    PubMed Central

    Bobes, Maria A.; Lage Castellanos, Agustin; Quiñones, Ileana; García, Lorna; Valdes-Sosa, Mitchell

    2013-01-01

    Different kinds of known faces activate brain areas to dissimilar degrees. However, the tuning to type of knowledge, and the temporal course of activation, of each area have not been well characterized. Here we measured, with functional magnetic resonance imaging, brain activity elicited by unfamiliar, visually familiar, and personally-familiar faces. We assessed response amplitude and duration using flexible hemodynamic response functions, as well as the tuning to face type, of regions within the face processing system. Core face processing areas (occipital and fusiform face areas) responded to all types of faces with only small differences in amplitude and duration. In contrast, most areas of the extended face processing system (medial orbito-frontal, anterior and posterior cingulate) had weak responses to unfamiliar and visually-familiar faces, but were highly tuned and exhibited prolonged responses to personally-familiar faces. This indicates that the neural processing of different types of familiar faces not only differs in degree, but is probably mediated by qualitatively distinct mechanisms. PMID:24130761

  18. Timing and tuning for familiarity of cortical responses to faces.

    PubMed

    Bobes, Maria A; Lage Castellanos, Agustin; Quiñones, Ileana; García, Lorna; Valdes-Sosa, Mitchell

    2013-01-01

    Different kinds of known faces activate brain areas to dissimilar degrees. However, the tuning to type of knowledge, and the temporal course of activation, of each area have not been well characterized. Here we measured, with functional magnetic resonance imaging, brain activity elicited by unfamiliar, visually familiar, and personally-familiar faces. We assessed response amplitude and duration using flexible hemodynamic response functions, as well as the tuning to face type, of regions within the face processing system. Core face processing areas (occipital and fusiform face areas) responded to all types of faces with only small differences in amplitude and duration. In contrast, most areas of the extended face processing system (medial orbito-frontal, anterior and posterior cingulate) had weak responses to unfamiliar and visually-familiar faces, but were highly tuned and exhibited prolonged responses to personally-familiar faces. This indicates that the neural processing of different types of familiar faces not only differs in degree, but is probably mediated by qualitatively distinct mechanisms.

  19. Leveraging First Response Time into the Knowledge Tracing Model

    ERIC Educational Resources Information Center

    Wang, Yutao; Heffernan, Neil T.

    2012-01-01

    The field of educational data mining has been using the Knowledge Tracing model, which only look at the correctness of student first response, for tracking student knowledge. Recently, lots of other features are studied to extend the Knowledge Tracing model to better model student knowledge. The goal of this paper is to analyze whether or not the…

  20. Motherhood and drug-dependency: the attributes of full-time versus part-time responsibility for child care.

    PubMed

    Jackson, M R; Berry, G L

    1994-10-01

    This study examined differences between the maternal characteristics of African-American drug-dependent mothers who have full-time responsibility for child care and those having part-time responsibility. The study revealed that full-time mothers have significantly higher levels of maternal adaptation than part-time mothers. For part-time mothers, the level of maternal adaptation or self-esteem did not fluctuate, regardless of whether she saw the child 4 days a week or once a month. The article identifies variables that may facilitate better maternal behaviors among drug-dependent mothers.

  1. Utilizing Response Time Distributions for Item Selection in CAT

    ERIC Educational Resources Information Center

    Fan, Zhewen; Wang, Chun; Chang, Hua-Hua; Douglas, Jeffrey

    2012-01-01

    Traditional methods for item selection in computerized adaptive testing only focus on item information without taking into consideration the time required to answer an item. As a result, some examinees may receive a set of items that take a very long time to finish, and information is not accrued as efficiently as possible. The authors propose two…

  2. The Effects of Spatial Stimulus-Response Compatibility on Choice Time Production Accuracy and Variability

    ERIC Educational Resources Information Center

    Rakitin, Brian C.

    2005-01-01

    Five experiments examined the relations between timing and attention using a choice time production task in which the latency of a spatial choice response is matched to a target interval (3 or 5 s). Experiments 1 and 2 indicated that spatial stimulus-response incompatibility increased nonscalar timing variability without affecting timing accuracy…

  3. Real-time earthquake monitoring: Early warning and rapid response

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A panel was established to investigate the subject of real-time earthquake monitoring (RTEM) and suggest recommendations on the feasibility of using a real-time earthquake warning system to mitigate earthquake damage in regions of the United States. The findings of the investigation and the related recommendations are described in this report. A brief review of existing real-time seismic systems is presented with particular emphasis given to the current California seismic networks. Specific applications of a real-time monitoring system are discussed along with issues related to system deployment and technical feasibility. In addition, several non-technical considerations are addressed including cost-benefit analysis, public perceptions, safety, and liability.

  4. The Impact of Item Format and Examinee Characteristics on Response Times

    ERIC Educational Resources Information Center

    Hess, Brian J.; Johnston, Mary M.; Lipner, Rebecca S.

    2013-01-01

    Current research on examination response time has focused on tests comprised of traditional multiple-choice items. Consequently, the impact of other innovative or complex item formats on examinee response time is not understood. The present study used multilevel growth modeling to investigate examinee characteristics associated with response time…

  5. Using Response Time to Detect Item Preknowledge in Computer-Based Licensure Examinations

    ERIC Educational Resources Information Center

    Qian, Hong; Staniewska, Dorota; Reckase, Mark; Woo, Ada

    2016-01-01

    This article addresses the issue of how to detect item preknowledge using item response time data in two computer-based large-scale licensure examinations. Item preknowledge is indicated by an unexpected short response time and a correct response. Two samples were used for detecting item preknowledge for each examination. The first sample was from…

  6. Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration

    NASA Technical Reports Server (NTRS)

    Hecox, K.; Squires, N.; Galambos, R.

    1975-01-01

    Short latency (under 10 msec) evoked responses elicited by bursts of white noise were recorded from the scalp of human subjects. Response alterations produced by changes in the noise burst duration (on-time) inter-burst interval (off-time), and onset and offset shapes are reported and evaluated. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise-time but was unaffected by changes in fall-time. The amplitude of wave V was insensitive to changes in signal rise-and-fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It is concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

  7. 5 CFR 1820.4 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... simple and more complex requests based on the amount of work and/or time needed to process the request..., or that the requester faces an imminent deadline for filing with, the Merit Systems Protection Board... knowledge and belief, explaining in detail the basis for requesting expedited processing. For example,...

  8. Physiological Evidence for Response Inhibition in Choice Reaction Time Tasks

    ERIC Educational Resources Information Center

    Burle, Boris; Vidal, Frank; Tandonnet, Christophe; Hasbroucq, Thierry

    2004-01-01

    Inhibition is a widely used notion proposed to account for data obtained in choice reaction time (RT) tasks. However, this concept is weakly supported by empirical facts. In this paper, we review a series of experiments using Hoffman reflex, transcranial magnetic stimulation and electroencephalography to study inhibition in choice RT tasks. We…

  9. 4 CFR 201.7 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Accounts RECOVERY ACCOUNTABILITY AND TRANSPARENCY BOARD PUBLIC INFORMATION AND REQUESTS § 201.7 Timing of... disclosed in part shall be marked or annotated to show the amount of information deleted unless doing so would harm an interest protected by an applicable exemption. The location of the information...

  10. Quantized response times are a signature of a neuronal bottleneck in decision

    PubMed Central

    Perona, Pietro

    2014-01-01

    The histograms of response times of optimal YES/NO decisions that are computed from a single sensory Poisson neuron are highly structured. In particular, response times in NO decisions are quantized to a small set of times, while response times in YES decisions have a multimodal structure. Both the times of NO decisions, as well as the modes of the the histogram of YES decisions, are associated to the number of action potentials that were necessary to reach the decision. Their value is a function of the firing rate of the neuron in response to the states of the stimulus. PMID:24782750

  11. Groundwater recharge and time lag measurement through Vertosols using impulse response functions

    NASA Astrophysics Data System (ADS)

    Hocking, Mark; Kelly, Bryce F. J.

    2016-04-01

    Throughout the world there are many stressed aquifers used to support irrigated agriculture. The Condamine River catchment (southern Queensland, Australia) is one example of a globally significant agricultural region where groundwater use has exceeded recharge over the last 50 years. There is a high dependence on groundwater in this catchment, because yearly rainfall is highly variable, and actual evapotranspiration often exceeds rainfall. To better manage the aquifer there is a need to correctly conceptualise the primary inputs and outputs of the system, and characterise the lags in system response to all forcings. In catchment models it is particularly important to correctly proportion diffuse (areal) rainfall recharge and to account for the lag between rainfall and recharge at the water table. Throughout large portions of the Condamine Catchment, groundwater levels are now 20 or more metres below the ground surface. This study aimed to better quantify the lag between rainfall and recharge at the water table using the predefined impulse response function in continuous time method (PIRFICT; von Asmuth et al., 2002; von Asmuth, 2012). The PIRFICT method was applied to 255 multi-decadal groundwater level data sets throughout the catchment. Inputs into the modelling include rainfall, irrigation deep drainage, stream water level, evapotranspiration, and groundwater extractions. As an independent check the PIRFICT model derived diffuse recharge estimates are compared to point lysimeter and geochemical recharge estimates in the Vertosol soils within this catchment. It is estimated using the PIRFICT method that in the Condamine Catchment between 1990 and 2012, the mean rain-derived groundwater recharge is 4.4 mm/year. Mean groundwater response from rainfall was determined to be 5.3 years: range 188 days to 48 years. The recharge estimates are consistent with both geochemical and lysimeter point measurements of recharge. It is concluded that where extensive groundwater

  12. Killing Two Birds with One Stone: Can Real-Time Pricing SupportRetail Competition and Demand Response?

    SciTech Connect

    Barbose, Galen; Bharvirkar, Ranjit; Goldman, Charles; Hopper,Nicole; Neenan, Bernie

    2006-04-25

    As retail choice states reach the end of their transitional, rate-cap periods, state regulators must decide what type of default supply service to provide to customers that have not switched to a competitive retail supplier. In a growing number of states, regulators have adopted real-time pricing (RTP) as the default service for large commercial and industrial (C&I) customers. Although this trend is driven chiefly by policy objectives related to retail competition, default service RTP may have the added benefit of stimulating demand response. To evaluate the potential role of RTP as a means to both ends--retail market development and demand response--we conducted a comprehensive review of experience with default RTP in the U.S. and examined the emergence of RTP as a product offering by competitive retail suppliers. Across the ten utilities with default RTP in place in 2005, between 5% and 35% of the applicable load remained on the rate. Based on interviews with competitive retailers, we find evidence to suggest that a comparable amount of load in these states has switched to hourly pricing arrangements with competitive retailers. Many customers on default or competitive hourly pricing are paying prices indexed to the real-time spot market, and thus have no advance knowledge of prices. Because the price responsiveness of customers under these conditions has yet to be formally analyzed, and relatively few efforts have been undertaken to help these customers become price responsive, the actual demand response impacts from hourly pricing in retail choice states remains largely an open question. However, we find that policymakers and other stakeholders in retail choice states have various strategies at their disposal to capture the potential demand response benefits from hourly pricing, while simultaneously supporting retail competition.

  13. Meteorological data assimilation for real-time emergency response

    SciTech Connect

    Sugiyama, G.; Chan, S.T.

    1996-11-01

    The US Department of Energy`s Atmospheric Release Advisory Capability (ARAC) provides real-time dose assessments of airborne pollutant releases. Diverse data assimilation techniques are required to meet the needs of a new generation of ARAC models and to take advantage of the rapidly expanding availability of meteorological data. We are developing a hierarchy of algorithms to provide gridded meteorological fields which can be used to drive dispersion codes or to provide initial fields for mesoscale models. Data to be processed include winds, temperature, moisture, and turbulence.

  14. A hybrid model for improving response time in distributed data mining.

    PubMed

    Krishnaswamy, Shonali; Loke, Seng W; Zaslasvky, Arkady

    2004-12-01

    This paper presents a hybrid distributed data mining (DDM) model for optimization of response time. The model combines a mobile agent approach with client server strategies to reduce the overall response time. The hybrid model proposes and develops accurate a priori estimates of the computation and communication components of response time as the costing strategy to support optimization. Experimental evaluation of the hybrid model is presented. PMID:15619946

  15. A hybrid model for improving response time in distributed data mining.

    PubMed

    Krishnaswamy, Shonali; Loke, Seng W; Zaslasvky, Arkady

    2004-12-01

    This paper presents a hybrid distributed data mining (DDM) model for optimization of response time. The model combines a mobile agent approach with client server strategies to reduce the overall response time. The hybrid model proposes and develops accurate a priori estimates of the computation and communication components of response time as the costing strategy to support optimization. Experimental evaluation of the hybrid model is presented.

  16. Do Young and Old Preschoolers Exhibit Response Bias Due to Different Mechanisms? Investigating Children's Response Time

    ERIC Educational Resources Information Center

    Okanda, Mako; Itakura, Shoji

    2011-01-01

    Previous studies have suggested that younger preschoolers exhibit a yes bias due to underdeveloped cognitive abilities, whereas older preschoolers exhibit a response bias due to other factors. To test this hypothesis, we investigated the response latency to yes-no questions pertaining to familiar and unfamiliar objects in 3- to 6-year-olds. The…

  17. Abrupt rise of new machine ecology beyond human response time

    PubMed Central

    Johnson, Neil; Zhao, Guannan; Hunsader, Eric; Qi, Hong; Johnson, Nicholas; Meng, Jing; Tivnan, Brian

    2013-01-01

    Society's techno-social systems are becoming ever faster and more computer-orientated. However, far from simply generating faster versions of existing behaviour, we show that this speed-up can generate a new behavioural regime as humans lose the ability to intervene in real time. Analyzing millisecond-scale data for the world's largest and most powerful techno-social system, the global financial market, we uncover an abrupt transition to a new all-machine phase characterized by large numbers of subsecond extreme events. The proliferation of these subsecond events shows an intriguing correlation with the onset of the system-wide financial collapse in 2008. Our findings are consistent with an emerging ecology of competitive machines featuring ‘crowds' of predatory algorithms, and highlight the need for a new scientific theory of subsecond financial phenomena. PMID:24022120

  18. Determinants of timing and amplitude in the plant general stress response.

    PubMed

    Bjornson, Marta; Dandekar, Abhaya; Dehesh, Katayoon

    2016-02-01

    Plants have evolved intricate signaling cascades to rapidly and effectively respond to biotic and abiotic challenges. The precise timing of these responses enables optimal resource reallocation to maintain the balance between stress adaptation and growth. Thus, an in-depth understanding of the immediate and long-term mechanisms regulating resource allocation is critical in deciphering how plants withstand environmental challenges. To date however, understanding of this tradeoff has focused on the amplitude of long-term responses, rather than the timing of rapid stress responses. This review presents current knowledge on kinetics of secondary messengers involved in regulation of rapid and general stress responses, followed by rapid stress responsive transduction machinery, and finally the transcriptional response of a functional general stress responsive cis-element. Within this context we discuss the role of timing of initial peak activation and later oscillating peak responses, and explore hormonal and stress signaling crosstalk confounding greater understanding of these cascades.

  19. Time Work by Overworked Professionals: Strategies in Response to the Stress of Higher Status.

    PubMed

    Moen, Phyllis; Lam, Jack; Ammons, Samantha; Kelly, Erin L

    2013-05-01

    How are professionals responding to the time strains brought on by the stress of their higher status jobs? Qualitative data from professionals reveal (a) general acceptance of the emerging temporal organization of professional work, including rising time demands and blurred boundaries around work/ nonwork times and places, and (b) time work as strategic responses to work intensification, overloads, and boundarylessness. We detected four time-work strategies: prioritizing time, scaling back obligations, blocking out time, and time shifting of obligations. These strategies are often more work-friendly than family-friendly, but "blocking out time" and "time shifting" suggest promising avenues for work-time policy and practice. PMID:24039337

  20. Time delays between core power production and external detector response from Monte Carlo calculations

    SciTech Connect

    Valentine, T.E.; Mihalczo, J.T.

    1996-08-01

    One primary concern for design of safety systems for reactors is the time response of external detectors to changes in the core. This paper describes a way to estimate the time delay between the core power production and the external detector response using Monte Carlo calculations and suggests a technique to measure the time delay. The Monte Carlo code KENO-NR was used to determine the time delay between the core power production and the external detector response for a conceptual design of the Advanced Neutron Source (ANS) reactor. The Monte Carlo estimated time delay was determined to be about 10 ms for this conceptual design of the ANS reactor.

  1. Effects of time response on the point spread function of a scanning radiometer.

    PubMed

    Smith, G L

    1994-10-20

    Scanning radiometers on satellites have a finite response time, because of the detector and the associated electronics. The radiometer measurement as it scans over a point source of radiation of unit strength is the point spread function (PSF). The time response causes a widening and skewing of the PSF. The PSF of a scanning radiometer that has well-focused optics together with time responses for the detector and electronic filter is treated in the time domain. The PSF can be expressed in terms of the system time response to a step input. For a first-order system time response, the displacement of the centroid is the product of the system time constant and the scan rate of the radiometer. The electronic filter further displaces the centroid of the PSF by the product of the scan rate and the filter time constant. Also, the width of the PSF in the scan direction will be increased because of the system time response. The minimum resolvable feature is of the order of the width of the PSF, thus the system time response limits the resolution in the scan direction that can be obtained. The analysis is illustrated by applying it to the Clouds and Earth Radiant Energy System experiment scanning radiometer.

  2. Posterior Predictive Checks for Conditional Independence between Response Time and Accuracy

    ERIC Educational Resources Information Center

    Bolsinova, Maria; Tijmstra, Jesper

    2016-01-01

    Conditional independence (CI) between response time and response accuracy is a fundamental assumption of many joint models for time and accuracy used in educational measurement. In this study, posterior predictive checks (PPCs) are proposed for testing this assumption. These PPCs are based on three discrepancy measures reflecting different…

  3. A Semiparametric Model for Jointly Analyzing Response Times and Accuracy in Computerized Testing

    ERIC Educational Resources Information Center

    Wang, Chun; Fan, Zhewen; Chang, Hua-Hua; Douglas, Jeffrey A.

    2013-01-01

    The item response times (RTs) collected from computerized testing represent an underutilized type of information about items and examinees. In addition to knowing the examinees' responses to each item, we can investigate the amount of time examinees spend on each item. Current models for RTs mainly focus on parametric models, which have the…

  4. 75 FR 79961 - Temporary Suspension of Certain Oil Spill Response Time Requirements To Support Deepwater Horizon...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-21

    ... Gulf of Mexico Deepwater Horizon SONSat the FOSC's request. 75 FR 37712. The rule also confirmed that...; 2050-AG63 Temporary Suspension of Certain Oil Spill Response Time Requirements To Support Deepwater.... Oil Spill Response Resources Return Time Several comments noted concerns about the return of assets...

  5. Setting the Response Time Threshold Parameter to Differentiate Solution Behavior from Rapid-Guessing Behavior

    ERIC Educational Resources Information Center

    Kong, Xiaojing J.; Wise, Steven L.; Bhola, Dennison S.

    2007-01-01

    This study compared four methods for setting item response time thresholds to differentiate rapid-guessing behavior from solution behavior. Thresholds were either (a) common for all test items, (b) based on item surface features such as the amount of reading required, (c) based on visually inspecting response time frequency distributions, or (d)…

  6. A Mixture Proportional Hazards Model with Random Effects for Response Times in Tests

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jörg-Tobias

    2016-01-01

    In this article, a new model for test response times is proposed that combines latent class analysis and the proportional hazards model with random effects in a similar vein as the mixture factor model. The model assumes the existence of different latent classes. In each latent class, the response times are distributed according to a…

  7. The Simplest Complete Model of Choice Response Time: Linear Ballistic Accumulation

    ERIC Educational Resources Information Center

    Brown, Scott D.; Heathcote, Andrew

    2008-01-01

    We propose a linear ballistic accumulator (LBA) model of decision making and reaction time. The LBA is simpler than other models of choice response time, with independent accumulators that race towards a common response threshold. Activity in the accumulators increases in a linear and deterministic manner. The simplicity of the model allows…

  8. First passage time: Connecting random walks to functional responses in heterogeneous environments (Invited)

    NASA Astrophysics Data System (ADS)

    Lewis, M. A.; McKenzie, H.; Merrill, E.

    2010-12-01

    In this talk I will outline first passage time analysis for animals undertaking complex movement patterns, and will demonstrate how first passage time can be used to derive functional responses in predator prey systems. The result is a new approach to understanding type III functional responses based on a random walk model. I will extend the analysis to heterogeneous environments to assess the effects of linear features on functional responses in wolves and elk using GPS tracking data.

  9. A Study of Time-dependent and Anisotropic Effects on the Deformation Response of Two Flywheel Designs

    NASA Technical Reports Server (NTRS)

    Saleeb, Atef F.; Arnold, Steven M.; Al-Zoubi, Nasser R.

    2003-01-01

    The influence of material time dependency and anisotropy in the context of two specific flywheel designs-preload and multi-directional composite (MDC)--is investigated. In particular, we focus on the following aspects: 1) geometric constraints, 2) material constraints, 3) loading type, and 4) the fundamental character of the time-dependent response, i.e., reversible or irreversible. The bulk of the results presented were obtained using a composite (PMC IM7/8552 at 135 C) material system. The material was characterized using a general multimechanism hereditary (viscoelastoplastic) model. As a general conclusion, the results have clearly shown that both the preload and the MDC rotor designs are significantly affected by time-dependent material behavior, which may impact the state of rotor balance and potentially reduce its operating life. In view of the results of the parametric studies and predictions made in the present study, the need for actual experimentation focusing on the time-dependent behavior of full-scale flywheel rotors is self-evident.

  10. A Study of Time-Dependent and Anisotropic Effects on the Deformation Response of Two Flywheel Designs

    NASA Astrophysics Data System (ADS)

    Saleeb, Atef F.; Arnold, Steven M.; Al-Zoubi, Nasser R.

    2003-01-01

    The influence of material time dependency and anisotropy in the context of two specific flywheel designs-preload and multi-directional composite (MDC)--is investigated. In particular, we focus on the following aspects: 1) geometric constraints, 2) material constraints, 3) loading type, and 4) the fundamental character of the time-dependent response, i.e., reversible or irreversible. The bulk of the results presented were obtained using a composite (PMC IM7/8552 at 135 C) material system. The material was characterized using a general multimechanism hereditary (viscoelastoplastic) model. As a general conclusion, the results have clearly shown that both the preload and the MDC rotor designs are significantly affected by time-dependent material behavior, which may impact the state of rotor balance and potentially reduce its operating life. In view of the results of the parametric studies and predictions made in the present study, the need for actual experimentation focusing on the time-dependent behavior of full-scale flywheel rotors is self-evident.

  11. Emotional Responses during Reading: Physiological Responses Predict Real-Time Reading Comprehension

    ERIC Educational Resources Information Center

    Daley, Samantha G.; Willett, John B.; Fischer, Kurt W.

    2014-01-01

    This study investigated the relationship between emotional responses and reading performance in middle-school students. Although a large number of prior studies have investigated the relationship between emotion and reading, those studies have concentrated primarily on relatively static and distal measures of emotion. In this research, we measured…

  12. Response Times for Correct and Incorrect Item Responses on Computerized Adaptive Tests

    ERIC Educational Resources Information Center

    Chang, Shu-Ren; Plake, Barbara S.; Ferdous, Abdullah A.

    2005-01-01

    This study examined the time different ability level examinees spend taking a CAT on demanding items to these examinees. It was also found that high able examinees spend more time on the pretest items, which are not tailored to the examinees' ability level, than do lower ability examinees. Higher able examinees showed persistence with test…

  13. Performing dynamic time history analyses by extension of the response spectrum method

    SciTech Connect

    Hulbert, G.M.

    1983-01-01

    A method is presented to calculate the dynamic time history response of finite element models using results from response spectrum analyses. The proposed ''modified'' time history method does not represent a new mathematical approach to dynamic analysis but suggests a more efficient ordering of the analytical equations and procedures. The modified time history method is considerably faster and less expensive to use than normal time history methods. This paper presents the theory and implementation of the modified time history approach along with comparisons of the modified and normal time history methods for a prototypic seismic piping design problem.

  14. Effect of prolonged bedrest and plus Gz acceleration on peripheral visual response time

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1973-01-01

    Peripheral visual response time changes during +G sub z acceleration following fourteen days of bedrest are considered as well as what effect prolonged bedrest has upon this response. Eighteen test lights, placed 10 deg are apart along the horizontal meridian of the subject's field of view, were presented in a random sequence. The subject was instructed to press a button as soon as a light appeared. Response time testing occurred periodically during bedrest and continuously during centrifugation testing. The results indicate that: (1) mean response time is significantly longer to stimuli imaged in the far periphery than to stimuli imaged closer to the line of sight; (2) mean response time at each stimulus position tends to be longer at plateau g than during the preacceleration baseline period; (3) mean response time tends to lengthen as the g level is increased; (4) peripheral visual response time during +G sub x acceleration at 2, 3.2, and 3.8 g was not a reliable advanced indicator that blackout was going to occur; and (5) the subject's field of view collapsed rapidly just before blackout. Bedrest data showed that the distribution of response times to stimuli imaged across the subject's horizontal retinal meridian remained remarkably constant from day to day during both the bedrest and recovery periods.

  15. The Largest Response Component in the Motor Cortex Reflects Movement Timing but Not Movement Type

    PubMed Central

    Sussillo, David; Ryu, Stephen I.

    2016-01-01

    Abstract Neural activity in monkey motor cortex (M1) and dorsal premotor cortex (PMd) can reflect a chosen movement well before that movement begins. The pattern of neural activity then changes profoundly just before movement onset. We considered the prediction, derived from formal considerations, that the transition from preparation to movement might be accompanied by a large overall change in the neural state that reflects when movement is made rather than which movement is made. Specifically, we examined “components” of the population response: time-varying patterns of activity from which each neuron’s response is approximately composed. Amid the response complexity of individual M1 and PMd neurons, we identified robust response components that were “condition-invariant”: their magnitude and time course were nearly identical regardless of reach direction or path. These condition-invariant response components occupied dimensions orthogonal to those occupied by the “tuned” response components. The largest condition-invariant component was much larger than any of the tuned components; i.e., it explained more of the structure in individual-neuron responses. This condition-invariant response component underwent a rapid change before movement onset. The timing of that change predicted most of the trial-by-trial variance in reaction time. Thus, although individual M1 and PMd neurons essentially always reflected which movement was made, the largest component of the population response reflected movement timing rather than movement type. PMID:27761519

  16. A new method for measuring the response time of the high pressure ionization chamber.

    PubMed

    Wang, Zhentao; Shen, Yixiong; An, Jigang

    2012-08-01

    Time response is an important performance characteristic for gas-pressurized ionization chambers. To study the time response, it is especially crucial to measure the ion drift time in high pressure ionization chambers. In this paper, a new approach is proposed to study the ion drift time in high pressure ionization chambers. It is carried out with a short-pulsed X-ray source and a high-speed digitizer. The ion drift time in the chamber is then determined from the digitized data. By measuring the ion drift time of a 15 atm xenon testing chamber, the method has been proven to be effective in the time response studies of ionization chambers.

  17. Detector response in time-of-flight mass spectrometry at high pulse repetition frequencies

    NASA Technical Reports Server (NTRS)

    Gulcicek, Erol E.; Boyle, James G.

    1993-01-01

    Dead time effects in chevron configured dual microchannel plates (MCPs) are investigated. Response times are determined experimentally for one chevron-configured dual MCP-type detector and two discrete dynode-type electron multipliers with 16 and 23 resistively divided stages. All of these detectors are found to be suitable for time-of-flight mass spectrometry (TOF MS), yielding 3-6-ns (FWHM) response times triggered on a single ion pulse. It is concluded that, unless there are viable solutions to overcome dead time disadvantages for continuous dynode detectors, suitable discrete dynode detectors for TOF MS appear to have a significant advantage for high repetition rate operation.

  18. Estimating Testing Time: The Effects of Item Characteristics on Response Latency.

    ERIC Educational Resources Information Center

    Halkitis, Perry N.; And Others

    The relationship between test item characteristics and testing time was studied for a computer-administered licensing examination. One objective of the study was to develop a model to predict testing time on the basis of known item characteristics. Response latencies (i.e., the amount of time taken by examinees to read, review, and answer items)…

  19. Effects of Arm Ergometry Exercise on the Reaction, Movement and Response Times of the Lower Extremities.

    ERIC Educational Resources Information Center

    Israel, Richard G.

    A study determined the effects of fatigue produced in the upper extremities on the reaction time, movement time, and response time of the lower extremities in 30 male subjects, 19-25 years old. Each subject participated in a 10 trial practice session one day prior to the experiment and immediately preceding the pre-test. The pre-test consisted of…

  20. Nonlinear response to a click in a time-domain model of the mammalian ear.

    PubMed

    Meaud, Julien; Lemons, Charlsie

    2015-07-01

    In this paper, a state-space implementation of a previously developed frequency-domain model of the cochlea is coupled to a lumped parameter model of the middle ear. After validation of the time-domain model by comparison of its steady-state response to results obtained with a frequency-domain formulation, the nonlinear response of the cochlea to clicks is investigated. As observed experimentally, a compressive nonlinearity progressively develops within the first few cycles of the response of the basilar membrane (BM). Furthermore, a time-frequency analysis shows that the instantaneous frequency of the BM response to a click progressively approaches the characteristic frequency. This phenomenon, called glide, is predicted at all stimulus intensities, as in experiments. In typical experiments with sensitive animals, the click response is characterized by a long ringing and the response envelope includes several lobes. In order to achieve similar results, inhomogeneities are introduced in the cochlear model. Simulations demonstrate the strong link between characteristics of the frequency response, such as dispersion and frequency-dependent nonlinearity, and characteristics of the time-domain response, such as the glide and a time-dependent nonlinearity. The progressive buildup of cochlear nonlinearity in response to a click is shown to be a consequence of the glide and of frequency-dependent nonlinearity.

  1. Consequences of Predicted or Actual Asteroid Impacts

    NASA Astrophysics Data System (ADS)

    Chapman, C. R.

    2003-12-01

    Earth impact by an asteroid could have enormous physical and environmental consequences. Impactors larger than 2 km diameter could be so destructive as to threaten civilization. Since such events greatly exceed any other natural or man-made catastrophe, much extrapolation is necessary just to understand environmental implications (e.g. sudden global cooling, tsunami magnitude, toxic effects). Responses of vital elements of the ecosystem (e.g. agriculture) and of human society to such an impact are conjectural. For instance, response to the Blackout of 2003 was restrained, but response to 9/11 terrorism was arguably exaggerated and dysfunctional; would society be fragile or robust in the face of global catastrophe? Even small impacts, or predictions of impacts (accurate or faulty), could generate disproportionate responses, especially if news media reports are hyped or inaccurate or if responsible entities (e.g. military organizations in regions of conflict) are inadequately aware of the phenomenology of small impacts. Asteroid impact is the one geophysical hazard of high potential consequence with which we, fortunately, have essentially no historical experience. It is thus important that decision makers familiarize themselves with the hazard and that society (perhaps using a formal procedure, like a National Academy of Sciences study) evaluate the priority of addressing the hazard by (a) further telescopic searches for dangerous but still-undiscovered asteroids and (b) development of mitigation strategies (including deflection of an oncoming asteroid and on- Earth civil defense). I exemplify these issues by discussing several representative cases that span the range of parameters. Many of the specific physical consequences of impact involve effects like those of other geophysical disasters (flood, fire, earthquake, etc.), but the psychological and sociological aspects of predicted and actual impacts are distinctive. Standard economic cost/benefit analyses may not

  2. The response time of the Changjiang plume to river discharge in summer

    NASA Astrophysics Data System (ADS)

    Yuan, Rui; Wu, Hui; Zhu, Jianrong; Li, Lu

    2016-02-01

    A three-dimensional numerical model was used to study the response time of the Changjiang (Yangtze) River plume to river discharge by artificially increasing the runoff over a short period and investigating the variation of salinity in the plume region. The time lagged between the change of river discharge and the change of salinity that reaches the 10% of the adjusted value is considered as the response time in this study. The response times in the plume region differed slightly when the river discharge during the spring tide and the neap tide was increased. Specifically, the response times near the river mouth and in the plume edge were ~ 1 days and more than 15 days, respectively. The brackish water volumes were also calculated to determine the variations in the plume extensions over time. A tracer was released to study the transport time from the Datong station to the East China Sea using the concept of water age. The tracer transport time ranged from 10 days near the river mouth to more than 50 days at the edge of the plume, which is much longer than the response time of the surface salinity.

  3. [An Exploratory Study of Methods for Quantifying the Analysis of Human Aggression. Avoidance of Time-Out from, and Withdrawal of, Positive Reinforcement in Humans: Reduction in Actual and Potential Reinforcement as a Stimulus for Aggression.

    ERIC Educational Resources Information Center

    Svinicki, Marilla Scott; Symannek, Brigitte

    The first of these two articles presents the methods, results, and discussions of six experiments which employed an avoidance of time-out from positive reinforcement schedule with human subjects to investigate: (1) whether time-outs may be considered aversive events; and (2) if so, whether the aversiveness was sufficient to produce aggressive…

  4. 49 CFR 234.103 - Timely response to report of malfunction.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS... Highway-Rail Grade Crossings § 234.103 Timely response to report of malfunction. (a) Upon receipt of...

  5. 49 CFR 234.103 - Timely response to report of malfunction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS... Highway-Rail Grade Crossings § 234.103 Timely response to report of malfunction. (a) Upon receipt of...

  6. 49 CFR 234.103 - Timely response to report of malfunction.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS... Highway-Rail Grade Crossings § 234.103 Timely response to report of malfunction. (a) Upon receipt of...

  7. Response of Vibrio fischeri to repeated exposures over time in an Online Toxicity Monitor

    EPA Science Inventory

    Online Toxicity Monitors have been developed to provide continuous, time-relevant information regarding water quality. These systems measure a physiological or behavioral response of a sentinel organism to changes water quality. One such system, the Microlan Toxcontrol, is base...

  8. Time/Loss Analysis in the development and evaluation of emergency response procedures

    SciTech Connect

    Francis, A.A.

    1994-08-01

    Time/Loss Analysis (T/LA) provides a standard for conducting technically consistent and objective evaluations of emergency response planning and procedures. T/LA is also a sound tool for evaluating the performance of safeguards and procedures.

  9. Research on Mail Surveys: Response Rates and Methods in Relation to Population Group and Time.

    ERIC Educational Resources Information Center

    Boser, Judith A.; Green, Kathy

    The purpose of this review was to look for trends across time in response rates and variables studied for published mail surveys and to compare response rates and variables studied for different target populations. Studies were identified in databases in four fields: education, psychology, business and marketing, and sociology. A total of 225…

  10. 75 FR 38603 - State Responsibility for the Timely Reporting and Posting of Certain Convictions and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-02

    ... Federal Motor Carrier Safety Administration State Responsibility for the Timely Reporting and Posting of... and posting of convictions for traffic offenses. This action is in response to the Department of... to ensuring highway safety. On July 31, 2002, FMCSA published a final rule (67 FR 49761)...

  11. Effect of Time of Day on Performance, Hormonal and Metabolic Response during a 1000-M Cycling Time Trial

    PubMed Central

    Fernandes, Alan Lins; Lopes-Silva, João Paulo; Bertuzzi, Rômulo; Casarini, Dulce Elena; Arita, Danielle Yuri; Bishop, David John; Lima-Silva, Adriano Eduardo

    2014-01-01

    The aim of this study was to determine the effect of time of day on performance, pacing, and hormonal and metabolic responses during a 1000-m cycling time-trial. Nine male, recreational cyclists visited the laboratory four times. During the 1st visit the participants performed an incremental test and during the 2nd visit they performed a 1000-m cycling familiarization trial. On the 3rd and 4th visits, the participants performed a 1000-m TT at either 8 am or 6 pm, in randomized, repeated-measures, crossover design. The time to complete the time trial was lower in the evening than in the morning (88.2±8.7 versus 94.7±10.9 s, respectively, p<0.05), but there was no significant different in pacing. However, oxygen uptake and aerobic mechanical power output at 600 and 1000 m tended to be higher in the evening (p<0.07 and 0.09, respectively). There was also a main effect of time of day for insulin, cortisol, and total and free testosterone concentration, which were all higher in the morning (+60%, +26%, +31% and +22%, respectively, p<0.05). The growth hormone, was twofold higher in the evening (p<0.05). The plasma glucose was ∼11% lower in the morning (p<0.05). Glucagon, norepinephrine, epinephrine and lactate were similar for the morning and evening trials (p>0.05), but the norepinephrine response to the exercise was increased in the morning (+46%, p<0.05), and it was accompanied by a 5-fold increase in the response of glucose. Muscle recruitment, as measured by electromyography, was similar between morning and evening trials (p>0.05). Our findings suggest that performance was improved in the evening, and it was accompanied by an improved hormonal and metabolic milieu. PMID:25289885

  12. Effect of time of day on performance, hormonal and metabolic response during a 1000-M cycling time trial.

    PubMed

    Fernandes, Alan Lins; Lopes-Silva, João Paulo; Bertuzzi, Rômulo; Casarini, Dulce Elena; Arita, Danielle Yuri; Bishop, David John; Lima-Silva, Adriano Eduardo

    2014-01-01

    The aim of this study was to determine the effect of time of day on performance, pacing, and hormonal and metabolic responses during a 1000-m cycling time-trial. Nine male, recreational cyclists visited the laboratory four times. During the 1st visit the participants performed an incremental test and during the 2nd visit they performed a 1000-m cycling familiarization trial. On the 3rd and 4th visits, the participants performed a 1000-m TT at either 8 am or 6 pm, in randomized, repeated-measures, crossover design. The time to complete the time trial was lower in the evening than in the morning (88.2±8.7 versus 94.7±10.9 s, respectively, p<0.05), but there was no significant different in pacing. However, oxygen uptake and aerobic mechanical power output at 600 and 1000 m tended to be higher in the evening (p<0.07 and 0.09, respectively). There was also a main effect of time of day for insulin, cortisol, and total and free testosterone concentration, which were all higher in the morning (+60%, +26%, +31% and +22%, respectively, p<0.05). The growth hormone, was twofold higher in the evening (p<0.05). The plasma glucose was ∼11% lower in the morning (p<0.05). Glucagon, norepinephrine, epinephrine and lactate were similar for the morning and evening trials (p>0.05), but the norepinephrine response to the exercise was increased in the morning (+46%, p<0.05), and it was accompanied by a 5-fold increase in the response of glucose. Muscle recruitment, as measured by electromyography, was similar between morning and evening trials (p>0.05). Our findings suggest that performance was improved in the evening, and it was accompanied by an improved hormonal and metabolic milieu.

  13. What factors influence drivers' response time for evasive maneuvers in real traffic?

    PubMed

    Dozza, Marco

    2013-09-01

    Distraction and inattention contribute to 80% of traffic accidents by delaying or hindering driver responses. However, distraction and inattention are not the only factors increasing response times. In addition, the extent to which different factors-related to the driver, the vehicle, or the environment-influence response times in real traffic is still uncertain. Such knowledge may significantly help the development of countermeasures to distraction and inattention. Naturalistic driving data promises to help determine the causes of distraction and inattention by understanding driver behavior in real traffic. Further, large naturalistic datasets are now publically available from a few sources such as UMTRI (University of Michigan Transportation Institute) and VTTI (Virginia Tech Transportation Institute). However, analysis of such data is made difficult by the intrinsic nature of the data: it is large and complex and the variables of interest are hard to control. This study used the public 100-car and 8-truck naturalistic data from VTTI to show how the NatWare toolkit developed at SAFER (Vehicle and Traffic Safety Center at Chalmers) can be used to determine the influence of several factors on response time. Among these factors, attendance to secondary tasks and eyes-off-road, which are indicators of driver's distraction and inattention, significantly delayed response times; the type of incident and response maneuver also affected response times; and finally, truck drivers responded more quickly than car drivers.

  14. Time and flow-direction responses of shear-styress-sensitive liquid crystal coatings

    NASA Technical Reports Server (NTRS)

    Reda, Daniel C.; Muraqtore, J. J.; Heinick, James T.

    1994-01-01

    Time and flow-direction responses of shear-stress liquid crystal coatings were exploresd experimentally. For the time-response experiments, coatings were exposed to transient, compressible flows created during the startup and off-design operation of an injector-driven supersonic wind tunnel. Flow transients were visualized with a focusing schlieren system and recorded with a 100 frame/s color video camera.

  15. Modeling the Climate Responses to Spectral Solar Variability on Decadal and Centennial Time Scales

    NASA Astrophysics Data System (ADS)

    Cahalan, Robert; Wen, Guoyong; Pilewskie, Peter; Harder, Jerald

    We apply two scenarios of external forcing, namely the SIM-based out-of-phase variations and the proxy-based in-phase variations, as input to a time-dependent radiative-convective model (RCM), and also to the GISS modelE GCM, to compute climate responses to solar variation on decadal time scale. We find that the maximum temperature response occurs in the upper stratosphere, while temperature response decreases downward to the surface for both scenarios, and both models. The upper stratospheric temperature peak-to-peak responses to out-of-phase solar forcing are 0.6 K in RCM and 0.9 K over the tropical region in GCM simulations, a factor of 5 times as large as responses to in-phase solar forcing. Stratospheric responses are in-phase with TSI (Total Solar Irradiance) variations. The modeled upper stratospheric temperature responses to the SORCE SIM observed SSI (Spectral Solar Irradiance) forcing are similar to the HALOE (Halogen Occultation Experiment) observed 11-year temperature variations. Surface responses to the two SSI scenarios are small for both RCM and GCM studies, as compared to the stratospheric responses. Though solar irradiance variations on centennial time scale are not well known, the two sce-narios of reconstructed TSI time series (i.e., the one based on 11-year cycle with background [Lean 2000] and the other one from flux transport that has much less background component [Wang, Lean, and Sheeley, 2005]) provide potential range of variations of TSI on centennial time scale. We apply phase relations among different spectral irradiance bands both from SIM observation and proxy reconstructions to the two scenarios of historical TSI to derive the as-sociated historical SSI. The historical SSI is used to drive the RCM. The updated atmosphere and ocean mixed coupled RCM including diffusion to deep-ocean will provide the first order estimate of temperature response to SSI variation on centennial time scales. We anticipate the stratosphere, troposphere, and

  16. Actual status of veralipride use

    PubMed Central

    Carranza-Lira, Sebastián

    2010-01-01

    During the climacteric period, several symptoms exist that motivate women to seek medical advice; one of the most common is the hot flush, which presents in 75%–85% of these during a variable time span. For the treatment of hot flush, several non-hormonal treatments exist; among them, veralipride has shown to be a useful treatment of vasomotor symptoms during the climacteric period. In recent times, several medical societies have discredited its use. The purpose of this review, therefore, is to define a measured position in relation to the use of this drug. On completion of this review, it was possible to conclude that this drug has an antidopaminergic mechanism of action. The recommended schedule is: 100 mg/day for 20 days, with 10 days drug free. Since the risk of undesirable secondary effects such as galactorrhea, mastodynia, and extrapyramidal can increase with use, no more than 3 treatment cycles are recommended. This drug has a residual effect that can allow drug-free intervals, which permit a longer time between schedules. PMID:20852674

  17. Enhancing the humidity response time of polymer optical fiber Bragg grating by using laser micromachining.

    PubMed

    Chen, Xianfeng; Zhang, Wei; Liu, Chen; Hong, Yanhua; Webb, David J

    2015-10-01

    The humidity sensors constructed from polymer optical fiber Bragg gratings (POFBG) respond to the water content change in the fiber induced by varying environmental condition. The water content change is a diffusion process. Therefore the response time of the POFBG sensor strongly depends on the geometry and size of the fiber. In this work we investigate the use of laser micromachining of D-shaped and slotted structures to improve the response time of polymer fiber grating based humidity sensors. A significant improvement in the response time has been achieved in laser micromachined D-shaped POFBG humidity sensors. The slotted geometry allows water rapid access to the core region but this does not of itself improve response time due to the slow expansion of the bulk of the cladding. We show that by straining the slotted sensor, the expansion component can be removed resulting in the response time being determined only by the more rapid, water induced change in core refractive index. In this way the response time is reduced by a factor of 2.5. PMID:26480109

  18. A window on perception: Response times of odontocete cetaceans in audiometric tests

    NASA Astrophysics Data System (ADS)

    Blackwood, Diane J.; Ridgway, Sam H.; Evans, William E.

    2002-05-01

    A standard psychometric measurement is response time, the interval elapsing between a stimulus and a response. While studies of response time have been published for humans and other terrestrial mammals, this study marks the first report of response times for odontocete cetaceans at threshold in an audiometric task. Two white whales (Delphinapterus leucas) and four Atlantic bottlenose dolphins (Tursiops truncatus) were given audiometric tests to determine masked hearing thresholds. Animals were tested at 26 frequencies over a range from 200 Hz to 100 kHz using pure tones. The test tone amplitudes covered a range of 20 dB re 1 microPascal including the hearing threshold of the animal at that frequency. Hearing thresholds varied from 87.5 dB to 125.5 dB depending on frequency, masking noise intensity and individual animal. Data was analyzed to determine characteristic relationships between response time and amplitude of test tone for each frequency and animal. The two whales responded significantly slower (640 ms, 0.001) than the four dolphins (430 ms). As in terrestrial animals, reaction time became shorter as stimulus strength increased. At threshold, median response time across frequencies within each animal varied about 150 ms.

  19. Response to gravity by Zea mays seedlings. I. Time course of the response

    NASA Technical Reports Server (NTRS)

    Bandurski, R. S.; Schulze, A.; Dayanandan, P.; Kaufman, P. B.

    1984-01-01

    Gravistimulation induces an asymmetric distribution of free indole-3-acetic acid (IAA) in the cortex-epidermis of the Zea mays L. cv 'Stowells Evergreen' mesocotyl within 15 minutes, the shortest time tested. IAA was measured by an isotope dilution method as the pentaflurobenzyl ester. The per cent IAA in the lower half of the mescotyl cortex was 56 to 57% at 15, 30, and 90 minutes after stimulus initiation. Curvature is detectable in the mescotyl within 3 minutes after beginning gravitropic stimulation. The rate of curvature of the mesocotyl increases during the first 60 minutes to maximum of about 30 degrees per hour. Thus, the growth asymmetry continues to increase for 45 minutes after hormone asymmetry is established. Free IAA occurs predominantly in the stele of the mesocotyl whereas esterified IAA is mainly in the mesocotyl cortex-epidermis. This compartmentation may permit determining in which tissue the hormone asymmetry arises. Current data suggest the asymmetry originated in the stele.

  20. The effect of loading time on flexible pavement dynamic response: a finite element analysis

    NASA Astrophysics Data System (ADS)

    Yin, Hao; Solaimanian, Mansour; Kumar, Tanmay; Stoffels, Shelley

    2007-12-01

    Dynamic response of asphalt concrete (AC) pavements under moving load is a key component for accurate prediction of flexible pavement performance. The time and temperature dependency of AC materials calls for utilizing advanced material characterization and mechanistic theories, such as viscoelasticity and stress/strain analysis. In layered elastic analysis, as implemented in the new Mechanistic-Empirical Pavement Design Guide (MEPDG), the time dependency is accounted for by calculating the loading times at different AC layer depths. In this study, the time effect on pavement response was evaluated by means of the concept of “pseudo temperature.” With the pavement temperature measured from instrumented thermocouples, the time and temperature dependency of AC materials was integrated into one single factor, termed “effective temperature.” Via this effective temperature, pavement responses under a transient load were predicted through finite element analysis. In the finite element model, viscoelastic behavior of AC materials was characterized through relaxation moduli, while the layers with unbound granular material were assumed to be in an elastic mode. The analysis was conducted for two different AC mixtures in a simplified flexible pavement structure at two different seasons. Finite element analysis results reveal that the loading time has a more pronounced impact on pavement response in the summer for both asphalt types. The results indicate that for reasonable prediction of dynamic response in flexible pavements, the effect of the depth-dependent loading time on pavement temperature should be considered.

  1. Complex Behavior of Time Response of HgCdTe HOT Photodetectors

    NASA Astrophysics Data System (ADS)

    Pawluczyk, J.; Piotrowski, J.; Pusz, W.; Koźniewski, A.; Orman, Z.; Gawron, W.; Piotrowski, A.

    2015-09-01

    We report on the time response of higher-operating-temperature (HOT, T ˜200 K to 300 K) fast long-cutoff-wavelength infrared (LWIR) HgCdTe photodetectors. For a long time, photoconductive and photoelectromagnetic devices operating near room temperature have been used as fast (sub-nanosecond) photodetectors. Unfortunately, such devices suffer from relatively low detectivity. Recent efforts have focused on heterojunction photodiodes that offer both fast response and high performance. This paper presents computer simulations and experimental studies that reveal mechanisms limiting the time response and design rules to achieve short response time of HOT LWIR photodiodes operating at both zero and reverse bias. Complex time response curves with fast and slow components have been observed. The latter has been found to be mainly determined by the ambipolar diffusion of photogenerated charge carriers and by the diffusion capacitance combined with the built-in or external series resistance. The limitations are especially pronounced in zero-biased photodiodes characterized by large diffusion capacitance, where series resistance of only 1 Ω significantly reduces the response speed of devices with 100 μm × 100 μm photosensitive area.

  2. Use of the Vocera Communications Badge Improves Public Safety Response Times

    PubMed Central

    Joslin, Jeremy D.; Goldberger, David; Johnson, Loretta; Waltz, D. Paul

    2016-01-01

    Objectives. Violence in the Emergency Department (ED) has been a long-standing issue complicated by deficiencies in staff training, ease of weapons access, and response availability of public safety officers. The Vocera Badge is being used by our staff to request public safety assistance in lieu of a formal phone call to the University Police Communications Center. We sought to learn if use of this technology improved officer response times to the ED. Methods. Mean response times were reviewed and descriptive statistics analyzed to determine if the use of the Vocera Badge improved public safety officer response times to the ED. Results. Average response times improved from an average of 3.2 minutes (SD = 0.456) in the 6 months before the use of the communication badges to an average of 1.02 minutes (SD = 0.319) in the 6 months after use began. Conclusions. The use of the Vocera Badge seemed to decrease response times of public safety officers to our ED compared with the traditional method of calling a dispatch center to request assistance. PMID:27127654

  3. Time Work by Overworked Professionals: Strategies in Response to the Stress of Higher Status

    PubMed Central

    Moen, Phyllis; Lam, Jack; Ammons, Samantha; Kelly, Erin L.

    2013-01-01

    How are professionals responding to the time strains brought on by the stress of their higher status jobs? Qualitative data from professionals reveal (a) general acceptance of the emerging temporal organization of professional work, including rising time demands and blurred boundaries around work/ nonwork times and places, and (b) time work as strategic responses to work intensification, overloads, and boundarylessness. We detected four time-work strategies: prioritizing time, scaling back obligations, blocking out time, and time shifting of obligations. These strategies are often more work-friendly than family-friendly, but “blocking out time” and “time shifting” suggest promising avenues for work-time policy and practice. PMID:24039337

  4. Anxiety and Sensory Over-Responsivity in Toddlers with Autism Spectrum Disorders: Bidirectional Effects across Time

    ERIC Educational Resources Information Center

    Green, Shulamite A.; Ben-Sasson, Ayelet; Soto, Timothy W.; Carter, Alice S.

    2012-01-01

    This report focuses on the emergence of and bidirectional effects between anxiety and sensory over-responsivity (SOR) in toddlers with autism spectrum disorders (ASD). Participants were 149 toddlers with ASD and their mothers, assessed at 2 annual time points. A cross-lag analysis showed that anxiety symptoms increased over time while SOR remained…

  5. Modeling Individual Differences in Numerical Reasoning Speed as a Random Effect of Response Time Limits

    ERIC Educational Resources Information Center

    Semmes, Robert; Davison, Mark L.; Close, Catherine

    2011-01-01

    If numerical reasoning items are administered under time limits, will two dimensions be required to account for the responses, a numerical ability dimension and a speed dimension? A total of 182 college students answered 74 numerical reasoning items. Every item was taken with and without time limits by half the students. Three psychometric models…

  6. Cortisol Response to Physical Activity in African American Toddlers Attending Full-Time Day Care

    ERIC Educational Resources Information Center

    Wall, Sarah J.; Rudisill, Mary E.; Gladden, L. Bruce

    2009-01-01

    The purpose of this study was to examine African American toddlers' cortisol response to acute physical play activity within a full-time subsidized day care environment. Saliva samples were taken from participants (N = 22, ages 26-45.5 months) before and after physical play and control play conditions at the same time of day. Actiheart[TM]monitors…

  7. Study and response time for the visual recognition of 'similarity' and identity

    NASA Technical Reports Server (NTRS)

    Derks, P. L.; Bauer, T. M.

    1974-01-01

    Four subjects compared successively presented pairs of line patterns for a match between any lines in the pattern (similarity) and for a match between all lines (identity). The encoding or study times for pattern recognition from immediate memory and the latency in responses to comparison stimuli were examined. Qualitative differences within and between subjects were most evident in study times.

  8. Inhibition of Return: Sensitivity and Criterion as a Function of Response Time

    ERIC Educational Resources Information Center

    Ivanoff, Jason; Klein, Raymond M.

    2006-01-01

    Inhibition of return (IOR) refers to a mechanism that results in a performance disadvantage typically observed when targets are presented at a location once occupied by a cue. Although the time course of the phenomenon--from the cue to the target--has been well studied, the time course of the effect--from target to response--is unknown. In 2…

  9. 5 CFR 2424.25 - Response of the exclusive representative; purpose; time limits; content; severance; service.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...; purpose; time limits; content; severance; service. 2424.25 Section 2424.25 Administrative Personnel... SERVICE IMPASSES PANEL FEDERAL LABOR RELATIONS AUTHORITY AND GENERAL COUNSEL OF THE FEDERAL LABOR... § 2424.25 Response of the exclusive representative; purpose; time limits; content; severance; service....

  10. 5 CFR 2424.25 - Response of the exclusive representative; purpose; time limits; content; severance; service.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...; purpose; time limits; content; severance; service. 2424.25 Section 2424.25 Administrative Personnel... SERVICE IMPASSES PANEL FEDERAL LABOR RELATIONS AUTHORITY AND GENERAL COUNSEL OF THE FEDERAL LABOR... § 2424.25 Response of the exclusive representative; purpose; time limits; content; severance; service....

  11. 5 CFR 2424.25 - Response of the exclusive representative; purpose; time limits; content; severance; service.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...; purpose; time limits; content; severance; service. 2424.25 Section 2424.25 Administrative Personnel... SERVICE IMPASSES PANEL FEDERAL LABOR RELATIONS AUTHORITY AND GENERAL COUNSEL OF THE FEDERAL LABOR... § 2424.25 Response of the exclusive representative; purpose; time limits; content; severance; service....

  12. Response Time as an Indicator of Test Taker Speed: Assumptions Meet Reality

    ERIC Educational Resources Information Center

    Wise, Steven L.

    2015-01-01

    The growing presence of computer-based testing has brought with it the capability to routinely capture the time that test takers spend on individual test items. This, in turn, has led to an increased interest in potential applications of response time in measuring intellectual ability and achievement. Goldhammer (this issue) provides a very useful…

  13. Relating Cerebellar Purkinje Cell Activity to the Timing and Amplitude of Conditioned Eyelid Responses

    PubMed Central

    Khilkevich, Andrei; Mauk, Michael D.

    2015-01-01

    How Purkinje cell (PC) activity may be altered by learning is central to theories of the cerebellum. Pavlovian eyelid conditioning, because of how directly it engages the cerebellum, has helped reveal many aspects of cerebellar learning and the underlying mechanisms. Theories of cerebellar learning assert that climbing fiber inputs control plasticity at synapses onto PCs, and thus PCs control the expression of learned responses. We tested this assertion by recording 184 eyelid PCs and 240 non-eyelid PCs during the expression of conditioned eyelid responses (CRs) in well trained rabbits. By contrasting the responses of eyelid and non-eyelid PCs and by contrasting the responses of eyelid PCs under conditions that produce differently timed CRs, we test the hypothesis that learning-related changes in eyelid PCs contribute to the learning and adaptive timing of the CRs. We used a variety of analyses to test the quantitative relationships between eyelid PC responses and the kinematic properties of the eyelid CRs. We find that the timing of eyelid PC responses varies systematically with the timing of the behavioral CRs and that there are differences in the magnitude of eyelid PC responses between larger-CR, smaller-CR, and non-CR trials. However, eyelid PC activity does not encode any single kinematic property of the behavioral CRs at a fixed time lag, nor does it linearly encode CR amplitude. Even so, the results are consistent with the hypothesis that learning-dependent changes in PC activity contribute to the adaptively timed expression of conditioned eyelid responses. PMID:25995469

  14. Effects of fixational saccades on response timing in macaque lateral geniculate nucleus.

    PubMed

    Saul, Alan B

    2010-11-01

    Even during active fixation, small eye movements persist that might be expected to interfere with vision. Numerous brain mechanisms probably contribute to discounting this jitter. Changes in the timing of responses in the visual thalamus associated with fixational saccades are considered in this study. Activity of single neurons in alert monkey lateral geniculate nucleus (LGN) was recorded during fixation while pseudorandom visual noise stimuli were presented. The position of the stimulus on the display monitor was adjusted based on eye position measurements to control for changes in retinal locations due to eye movements. A method for extracting nonstationary first-order response mechanisms was applied, so that changes around the times of saccades could be observed. Saccade-related changes were seen in both amplitude and timing of geniculate responses. Amplitudes were greatly reduced around saccades. Timing was retarded slightly during a window of about 200 ms around saccades. That is, responses became more sustained. These effects were found in both parvocellular and magnocellular neurons. Timing changes in LGN might play a role in maintaining cortical responses to visual stimuli in the presence of eye movements, compensating for the spatial shifts caused by saccades via these shifts in timing. PMID:20932359

  15. Simplified models to analyse time- and dose-dependent responses of populations to toxicants.

    PubMed

    Sánchez-Bayo, Francisco; Goka, Kouichi

    2007-10-01

    The basis of ecotoxicology lies currently in the dose-response of organisms to toxicants, as typically described by probit and logistic models. While recognising its merits, standard endpoints ignore the process of toxicity with time, and consequently our ability to predict direct toxic effects in environmental risk assessments is seriously curtailed. Although the response of toxicants with time has been studied before, its application in ecotoxicology remains underutilised. One reason is that no convincing mechanism has been proposed to explain the hyperbolic curves of such responses, whereas a variety of models have been used to describe them. The explanation of both time- and dose-dependent responses is found ultimately in the natural variability of receptor sites among individuals of populations exposed to a toxicant inhibitor with time. The process can be explained by the kinetics of inhibition, and is appropriately described by a simple mathematical expression like the Michaelis-Menten equation, though other asymptotic models (e.g. logistic model) can also be used. The advantage of the hyperbolic model is that median effect values (e.g. LC(50) for dose- and ET(50) for time-dependent responses) enable calculation of toxicity effects at any concentration level and/or time of exposure, thus making it especially attractive for risk assessment. PMID:17624612

  16. Presentation and response timing accuracy in Adobe Flash and HTML5/JavaScript Web experiments.

    PubMed

    Reimers, Stian; Stewart, Neil

    2015-06-01

    Web-based research is becoming ubiquitous in the behavioral sciences, facilitated by convenient, readily available participant pools and relatively straightforward ways of running experiments: most recently, through the development of the HTML5 standard. Although in most studies participants give untimed responses, there is a growing interest in being able to record response times online. Existing data on the accuracy and cross-machine variability of online timing measures are limited, and generally they have compared behavioral data gathered on the Web with similar data gathered in the lab. For this article, we took a more direct approach, examining two ways of running experiments online-Adobe Flash and HTML5 with CSS3 and JavaScript-across 19 different computer systems. We used specialist hardware to measure stimulus display durations and to generate precise response times to visual stimuli in order to assess measurement accuracy, examining effects of duration, browser, and system-to-system variability (such as across different Windows versions), as well as effects of processing power and graphics capability. We found that (a) Flash and JavaScript's presentation and response time measurement accuracy are similar; (b) within-system variability is generally small, even in low-powered machines under high load; (c) the variability of measured response times across systems is somewhat larger; and (d) browser type and system hardware appear to have relatively small effects on measured response times. Modeling of the effects of this technical variability suggests that for most within- and between-subjects experiments, Flash and JavaScript can both be used to accurately detect differences in response times across conditions. Concerns are, however, noted about using some correlational or longitudinal designs online.

  17. Presentation and response timing accuracy in Adobe Flash and HTML5/JavaScript Web experiments.

    PubMed

    Reimers, Stian; Stewart, Neil

    2015-06-01

    Web-based research is becoming ubiquitous in the behavioral sciences, facilitated by convenient, readily available participant pools and relatively straightforward ways of running experiments: most recently, through the development of the HTML5 standard. Although in most studies participants give untimed responses, there is a growing interest in being able to record response times online. Existing data on the accuracy and cross-machine variability of online timing measures are limited, and generally they have compared behavioral data gathered on the Web with similar data gathered in the lab. For this article, we took a more direct approach, examining two ways of running experiments online-Adobe Flash and HTML5 with CSS3 and JavaScript-across 19 different computer systems. We used specialist hardware to measure stimulus display durations and to generate precise response times to visual stimuli in order to assess measurement accuracy, examining effects of duration, browser, and system-to-system variability (such as across different Windows versions), as well as effects of processing power and graphics capability. We found that (a) Flash and JavaScript's presentation and response time measurement accuracy are similar; (b) within-system variability is generally small, even in low-powered machines under high load; (c) the variability of measured response times across systems is somewhat larger; and (d) browser type and system hardware appear to have relatively small effects on measured response times. Modeling of the effects of this technical variability suggests that for most within- and between-subjects experiments, Flash and JavaScript can both be used to accurately detect differences in response times across conditions. Concerns are, however, noted about using some correlational or longitudinal designs online. PMID:24903687

  18. First passage time analysis of animal movement and insights into the functional response.

    PubMed

    McKenzie, Hannah W; Lewis, Mark A; Merrill, Evelyn H

    2009-01-01

    Movement plays a role in structuring the interactions between individuals, their environment, and other species. Although movement models coupled with empirical data are widely used to study animal distribution, they have seldom been used to study search time. This paper proposes first passage time as a novel approach for understanding the effect of the landscape on animal movement and search time. In the context of animal movement, first passage time is the time taken for an animal to reach a specified site for the first time. We synthesize current first passage time theory and derive a general first passage time equation for animal movement. This equation is related to the Fokker-Planck equation, which is used to describe the distribution of animals in the landscape. We illustrate the first passage time method by analyzing the effect of territorial behavior on the time required for a red fox to locate prey throughout its home range. Using first passage time to compute search times, we consider the effect of two different searching modes on a functional response. We show that random searching leads to a Holling type III functional response. First passage time analysis provides a new tool for studying how animal movement may influence ecological processes. PMID:18825463

  19. Effects of aircraft motion on passengers' comfort ratings and response times.

    PubMed

    Rinalducci, E J

    1980-02-01

    Comfort ratings and response times for changes in the experienced level of comfort were examined in 20 subjects using the NASA Flight Research Center's Jetstar aircraft modified to carry the GPAS system (General Purpose Airborne Simulator). Data were obtained for each of the subjects during two runs of 10 1-min. flight segments. In general, as the magnitude of aircraft motion increased in either the vertical or transverse (lateral) directions, there was an increase in feelings of discomfort and a decrease in response times to those changes. These results suggest parallels between the large body of laboratory data on human reaction time and that collected in this field study on response times to changes in ride comfort.

  20. Responses of inferior collicular neurones of bats to tone bursts with different rise times

    PubMed Central

    Suga, N.

    1971-01-01

    1. A study was made of the responses of single neurones in the inferior colliculus of bats to tone bursts with different rise times (or with different rates of amplitude increase) in order to determine whether the neurones were specialized for analysis of amplitude-modulated sound, especially the rising phase in amplitude. 2. The response patterns of neurones which showed phasic on-responses usually did not change with rise time, although the response patterns of some neurones changed from phasic on-responses to inhibitory responses. 3. The thresholds of responses to tone bursts increased when the rise time was lengthened. The amount of increase greatly differed from neurone to neurone. For the excitation of neurones which showed a large increase in threshold, the stimulus amplitude should quickly increase in amplitude. For tone bursts with a short rise time, some neurones showed an upper-threshold above which the sounds failed to excite them. The upper-threshold usually disappeared when the rise time was lengthened. For the excitation of neurones which showed an upper-threshold, the rate of amplitude increase and its extent were very important parameters. 4. Lengthening the rise time of a tone burst from 0·5 to 98 msec caused various types of change in the excitatory area. In some cases, there was a diminution of the area and, in others, there was an expansion of the area. Neurones showing these changes may be considered to be specialized for responding to tone bursts with either a rapid or slow increase in amplitude. 5. Changes with rise time occurred not only in the excitatory area, but also in the inhibitory area. The change in the inhibitory area of a given neurone, however, was not necessarily the same as that in the excitatory area. 6. The latency of response usually changed as a function of stimulus amplitude and rise time. In 26% of the neurones studied, however, the latency was relatively constant regardless of stimulus amplitude and rise time. Some of

  1. Influence of Pause Duration and Nod Response Timing in Dialogue between Human and Communication Robot

    NASA Astrophysics Data System (ADS)

    Takasugi, Shoji; Yoshida, Shohei; Okitsu, Kengo; Yokoyama, Masanori; Yamamoto, Tomohito; Miyake, Yoshihiro

    The purpose of this study is to clarify the influence from timing of utterance and body motion in dialogue between human and robot. We controlled pause duration and nod response timing in robot-side, and analyzed impression of communication in human-side by using Scheffe's Paired Comparison method. The results revealed that the impression of communication significantly modified by changing the pause duration and nod response timing. And, timing pattern of the impression altered diversely in elderly people than in younger, indicating that elderly generation uses various timing control mechanisms. From these results, it was suggested that timing control and impression of communication are mutually influenced, and this mechanism is thought to be useful to realize human-robot communication system for elderly generation.

  2. Information Gap Analysis: near real-time evaluation of disaster response

    NASA Astrophysics Data System (ADS)

    Girard, Trevor

    2014-05-01

    Disasters, such as major storm events or earthquakes, trigger an immediate response by the disaster management system of the nation in question. The quality of this response is a large factor in its ability to limit the impacts on the local population. Improving the quality of disaster response therefore reduces disaster impacts. Studying past disasters is a valuable exercise to understand what went wrong, identify measures which could have mitigated these issues, and make recommendations to improve future disaster planning and response. While such ex post evaluations can lead to improvements in the disaster management system, there are limitations. The main limitation that has influenced this research is that ex post evaluations do not have the ability to inform the disaster response being assessed for the obvious reason that they are carried out long after the response phase is over. The result is that lessons learned can only be applied to future disasters. In the field of humanitarian relief, this limitation has led to the development of real time evaluations. The key aspect of real time humanitarian evaluations is that they are completed while the operation is still underway. This results in findings being delivered at a time when they can still make a difference to the humanitarian response. Applying such an approach to the immediate disaster response phase requires an even shorter time-frame, as well as a shift in focus from international actors to the nation in question's government. As such, a pilot study was started and methodology developed, to analyze disaster response in near real-time. The analysis uses the information provided by the disaster management system within the first 0 - 5 days of the response. The data is collected from publicly available sources such as ReliefWeb and sorted under various categories which represent each aspect of disaster response. This process was carried out for 12 disasters. The quantity and timeliness of information

  3. Time history solution program, L225 (TEV126). Volume 2: Supplemental system design and maintenance document. [for airplane dynamic response using frequency response data

    NASA Technical Reports Server (NTRS)

    Tornallyay, A.; Clemmons, R. E.; Kroll, R. I.

    1979-01-01

    The time history solution program L225 (TEV126) is described. The program calculates the time responses of a linear system by convoluting the impulsive response functions with the time dependent excitation. The convolution is performed as a multiplication in the frequency domain. Fast Fourier transform techniques are used to transform the product back into the time domain to obtain response time histories. The design and structure of the program is presented.

  4. Decision deadlines and uncertainty monitoring: the effect of time constraints on uncertainty and perceptual responses.

    PubMed

    Zakrzewski, Alexandria C; Coutinho, Mariana V C; Boomer, Joseph; Church, Barbara A; Smith, J David

    2014-06-01

    The behavioral uncertainty response has grounded the study of animal metacognition and influenced the study of human psychophysics. However, the interpretation of this response is debated--especially whether it is a behavioral index of metacognition. The authors advanced this interpretation using the dissociative technique of response deadlines. Uncertainty responding, if it is higher level or metacognitive, should depend on a slower, more controlled decisional process and be more vulnerable to time constraints. Humans performed sparse-uncertain-dense or sparse-middle-dense discriminations in which, respectively, they could decline difficult trials or positively identify middle stimuli. Uncertainty responses were sharply and selectively reduced under a decision deadline, as compared to primary perceptual responses (i.e., "sparse," "middle," and "dense" responses). This dissociation suggests that the uncertainty response does reflect a higher-level, decisional response. It grants the uncertainty response a distinctive psychological role in its task and encourages an interpretation of this response as an elemental behavioral index of uncertainty that deserves continuing research.

  5. Analyzing effects of aperture size and applied voltage on the response time

    NASA Astrophysics Data System (ADS)

    Kim, YooKwang; Lee, Jin Su; Won, Yong Hyub

    2016-03-01

    Electrowetting lens is a promising technique for non-mechanical vari-focal lens, because of fast response time, wide expressible diopter, and etc. Although electrowetting related papers are actively published, no one did not clearly define the relationship among electrowetting parameters, especially in AC driven case. Analysis for AC voltage driving is needed because AC electrowetting has many advantages like low hysteresis and short settling time. In this experiment we confirmed that the response time depends on aperture size and applied voltage. Response time measurement for lens aperture of 200-1000um and applied voltage of 0-70V with 1kHz frequency was conducted. Experimental data was compared with simulation result by COMSOL Multiphysics program with the same condition, and they correspond with each other well. As voltage increases, the overshoot height becomes higher, so it has longer oscillation and settling time. On the other hand if aperture size decreases, the surface tension of lens wall could be delivered effectively to the center region of meniscus, so it has less oscillation and shorter settling time. The result was that in 500um aperture no more than 30V should be applied to ensure 1ms response time. In 200um aperture, the voltage limit is disappeared.

  6. Coherent averaging of the passive fathometer response using short correlation time.

    PubMed

    Traer, James; Gerstoft, Peter

    2011-12-01

    The passive fathometer algorithm was applied to data from two drifting array experiments in the Mediterranean, Boundary 2003 and 2004. The passive fathometer response was computed with correlation times from 0.34 to 90 s and, for correlation times less than a few seconds, the observed signal-to-noise ratio (SNR) agrees with a 1D model of SNR of the passive fathometer response in an ideal waveguide. In the 2004 experiment, the fathometer response showed the array depth varied periodically with an amplitude of 1 m and a period of 7 s consistent with wave driven motion of the array. This introduced a destructive interference, which prevents the SNR growing with increasing correlation time. A peak-tracking algorithm applied to the fathometer response of experimental data was used to remove this motion allowing the coherent passive fathometer response to be averaged over several minutes without destructive interference. Multirate adaptive beamforming, using 90 s correlation time to form adaptive steer vectors which were applied to 0.34 s data snapshots, increases the SNR of the passive fathometer response. PMID:22225020

  7. Spatial Attention and Temporal Expectation Under Timed Uncertainty Predictably Modulate Neuronal Responses in Monkey V1.

    PubMed

    Sharma, Jitendra; Sugihara, Hiroki; Katz, Yarden; Schummers, James; Tenenbaum, Joshua; Sur, Mriganka

    2015-09-01

    The brain uses attention and expectation as flexible devices for optimizing behavioral responses associated with expected but unpredictably timed events. The neural bases of attention and expectation are thought to engage higher cognitive loci; however, their influence at the level of primary visual cortex (V1) remains unknown. Here, we asked whether single-neuron responses in monkey V1 were influenced by an attention task of unpredictable duration. Monkeys covertly attended to a spot that remained unchanged for a fixed period and then abruptly disappeared at variable times, prompting a lever release for reward. We show that monkeys responded progressively faster and performed better as the trial duration increased. Neural responses also followed monkey's task engagement-there was an early, but short duration, response facilitation, followed by a late but sustained increase during the time monkeys expected the attention spot to disappear. This late attentional modulation was significantly and negatively correlated with the reaction time and was well explained by a modified hazard function. Such bimodal, time-dependent changes were, however, absent in a task that did not require explicit attentional engagement. Thus, V1 neurons carry reliable signals of attention and temporal expectation that correlate with predictable influences on monkeys' behavioral responses. PMID:24836689

  8. Time-lag effects of global vegetation responses to climate change.

    PubMed

    Wu, Donghai; Zhao, Xiang; Liang, Shunlin; Zhou, Tao; Huang, Kaicheng; Tang, Bijian; Zhao, Wenqian

    2015-09-01

    Climate conditions significantly affect vegetation growth in terrestrial ecosystems. Due to the spatial heterogeneity of ecosystems, the vegetation responses to climate vary considerably with the diverse spatial patterns and the time-lag effects, which are the most important mechanism of climate-vegetation interactive effects. Extensive studies focused on large-scale vegetation-climate interactions use the simultaneous meteorological and vegetation indicators to develop models; however, the time-lag effects are less considered, which tends to increase uncertainty. In this study, we aim to quantitatively determine the time-lag effects of global vegetation responses to different climatic factors using the GIMMS3g NDVI time series and the CRU temperature, precipitation, and solar radiation datasets. First, this study analyzed the time-lag effects of global vegetation responses to different climatic factors. Then, a multiple linear regression model and partial correlation model were established to statistically analyze the roles of different climatic factors on vegetation responses, from which the primary climate-driving factors for different vegetation types were determined. The results showed that (i) both the time-lag effects of the vegetation responses and the major climate-driving factors that significantly affect vegetation growth varied significantly at the global scale, which was related to the diverse vegetation and climate characteristics; (ii) regarding the time-lag effects, the climatic factors explained 64% variation of the global vegetation growth, which was 11% relatively higher than the model ignoring the time-lag effects; (iii) for the area with a significant change trend (for the period 1982-2008) in the global GIMMS3g NDVI (P < 0.05), the primary driving factor was temperature; and (iv) at the regional scale, the variation in vegetation growth was also related to human activities and natural disturbances. Considering the time-lag effects is quite

  9. Time-lag effects of global vegetation responses to climate change.

    PubMed

    Wu, Donghai; Zhao, Xiang; Liang, Shunlin; Zhou, Tao; Huang, Kaicheng; Tang, Bijian; Zhao, Wenqian

    2015-09-01

    Climate conditions significantly affect vegetation growth in terrestrial ecosystems. Due to the spatial heterogeneity of ecosystems, the vegetation responses to climate vary considerably with the diverse spatial patterns and the time-lag effects, which are the most important mechanism of climate-vegetation interactive effects. Extensive studies focused on large-scale vegetation-climate interactions use the simultaneous meteorological and vegetation indicators to develop models; however, the time-lag effects are less considered, which tends to increase uncertainty. In this study, we aim to quantitatively determine the time-lag effects of global vegetation responses to different climatic factors using the GIMMS3g NDVI time series and the CRU temperature, precipitation, and solar radiation datasets. First, this study analyzed the time-lag effects of global vegetation responses to different climatic factors. Then, a multiple linear regression model and partial correlation model were established to statistically analyze the roles of different climatic factors on vegetation responses, from which the primary climate-driving factors for different vegetation types were determined. The results showed that (i) both the time-lag effects of the vegetation responses and the major climate-driving factors that significantly affect vegetation growth varied significantly at the global scale, which was related to the diverse vegetation and climate characteristics; (ii) regarding the time-lag effects, the climatic factors explained 64% variation of the global vegetation growth, which was 11% relatively higher than the model ignoring the time-lag effects; (iii) for the area with a significant change trend (for the period 1982-2008) in the global GIMMS3g NDVI (P < 0.05), the primary driving factor was temperature; and (iv) at the regional scale, the variation in vegetation growth was also related to human activities and natural disturbances. Considering the time-lag effects is quite

  10. Temperature Responses to Spectral Solar Variability on Decadal and Centennial Time Scales

    NASA Astrophysics Data System (ADS)

    Cahalan, Robert; Wen, Guoyong; Pilewskie, Peter; Harder, Jerald

    2010-05-01

    We apply two scenarios of 11-year solar spectral forcing, namely SIM-based out-of-phase variations and proxy-based in-phase variations, as input to a time-dependent radiative-convective model (RCM), and also to the GISS modelE GCM. For both scenarios, and both models, we find that the maximum temperature response occurs in the upper stratosphere, and temperature responses decrease downward to the surface. The upper stratospheric temperature peak-to-peak responses to out-of-phase solar forcing are ~0.6 K in RCM and ~0.9 K over the tropical region in GCM simulations, a factor of ~5 times as large as responses to in-phase solar forcing. Stratospheric responses are in-phase with TSI (Total Solar Irradiance) variations. The modeled upper stratospheric temperature response to the SORCE SIM observed SSI (Spectral Solar Irradiance) forcing resembles 11-year temperature variations observed with HALOE (Halogen Occultation Experiment). Surface responses to the two SSI scenarios are small for both RCM and GCM studies, as compared to stratospheric responses. Though solar irradiance variations on centennial time scale are not well known, the two scenarios of reconstructed TSI time series (i.e., one based on 11-year cycles with background [Lean 2000] and the second from flux transport that has much less background change [Wang, Lean, and Sheeley, 2005]) provide a range of variations of TSI on centennial time scales. We apply phase relations among different spectral irradiance bands both from SIM observation and proxy reconstructions to the two scenarios of historical TSI. The spectral solar forcing is used to drive the RCM. The updated atmosphere and ocean mixed coupled RCM including diffusion to deep-ocean provides a first-order estimate of climate response. We report the different responses of stratosphere, troposphere, and ocean surface to these 4 scenarios of centennial spectral solar forcing. We further discuss the mechanisms for atmosphere-ocean and stratosphere

  11. Modeling the Temperature Responses to Spectral Solar Variability on Decadal and Centennial Time Scales

    NASA Astrophysics Data System (ADS)

    Cahalan, R. F.; Wen, G.; Pilewskie, P.; Harder, J. W.

    2010-12-01

    Atmospheric temperature responses to decadal solar variations are computed for two scenarios of solar spectral irradiance (SSI), SIM-based out-of-phase and proxy-based in-phase variations, using a time-dependent radiative-convective model (RCM), and also GISS modelE (GCM.) For both scenarios and both models, maximum responses occur in upper stratosphere, decreasing downward to the surface. Upper stratospheric temperature peak-to-peak responses to out-of-phase forcing are ~0.6 K in RCM and ~0.9 K over tropics in GCM, ~5x as large as responses to in-phase forcing. Stratospheric responses are in-phase with TSI (Total Solar Irradiance). Modeled upper stratospheric temperature responses to SIM-based forcing are similar to 11-year temperature variations observed with HALOE (Halogen Occultation Experiment). For both RCM and GCM, surface responses to the two scenarios are significantly smaller than stratospheric responses. On centennial timescales, SSI variations are poorly known. However, two scenarios of reconstructed TSI, one based on 11-year cycle with background [Lean 2000] and the other on flux transport with much less background [Wang, Lean, and Sheeley, 2005], provide a potential range of TSI variations. We apply phase relations among different SSI bands both from SIM observations and proxy reconstructions to the two scenarios of historical TSI to derive associated historical SSI, which then drives the RCM. The updated atmosphere and ocean mixed coupled RCM including diffusion to deep-ocean provide a first order estimate of temperature responses to SSI variations on centennial time scales. We discuss potential mechanisms for atmosphere-ocean and stratosphere-troposphere couplings responsible for the climate responses to spectral solar variations.

  12. Time-dependent influence of sensorimotor set on automatic responses in perturbed stance

    NASA Technical Reports Server (NTRS)

    Chong, R. K.; Horak, F. B.; Woollacott, M. H.; Peterson, B. W. (Principal Investigator)

    1999-01-01

    These experiments tested the hypothesis that the ability to change sensorimotor set quickly for automatic responses depends on the time interval between successive surface perturbations. Sensorimotor set refers to the influence of prior experience or context on the state of the sensorimotor system. Sensorimotor set for postural responses was influenced by first giving subjects a block of identical backward translations of the support surface, causing forward sway and automatic gastrocnemius responses. The ability to change set quickly was inferred by measuring the suppression of the stretched antagonist gastrocnemius responses to toes-up rotations causing backward sway, following the translations. Responses were examined under short (10-14 s) and long (19-24 s) inter-trial intervals in young healthy subjects. The results showed that subjects in the long-interval group changed set immediately by suppressing gastrocnemius to 51% of translation responses within the first rotation and continued to suppress them over succeeding rotations. In contrast, subjects in the short-interval group did not change set immediately, but required two or more rotations to suppress gastrocnemius responses. By the last rotation, the short-interval group suppressed gastrocnemius responses to 33%, similar to the long-interval group of 29%. Associated surface plantarflexor torque resulting from these responses showed similar results. When rotation and translation perturbations alternated, however, the short-interval group was not able to suppress gastrocnemius responses to rotations as much as the long-interval group, although they did suppress more than in the first rotation trial after a series of translations. Set for automatic responses appears to linger, from one trial to the next. Specifically, sensorimotor set is more difficult to change when surface perturbations are given in close succession, making it appear as if set has become progressively stronger. A strong set does not mean

  13. Automaticity and conscious control in single and choice response time versions of the Perruchet effect.

    PubMed

    Livesey, Evan J; Costa, Daniel S J

    2014-01-01

    The Perruchet effect refers to a dissociation between conscious expectation of an event and the strength or speed of the response elicited by that event, which is revealed through sequential analyses of consecutive trials. For instance in a cued go/no-go task, over a run of consecutive go responses, participants perform the go task with increasing speed but display decreasing expectancy of the go response when asked to rate the likelihood of its occurrence, in line with a gambler's fallacy. The effect has conventionally been shown in procedures that measure expectancy and responding in separate blocks of trials (separate measurement) or measure both on the same trial (concurrent measurement). Here we directly compared the trends produced in separate and concurrent measurement procedures, using single response and two-choice response procedures. While the single response showed the same trends regardless of measurement style, the Perruchet dissociation disappeared when concurrent measurement was used with the choice response task. Furthermore, in the concurrent measurement versions of both tasks, those participants who produced a consistent gambler's fallacy did not show the standard effects of positive recency that underpin the Perruchet effect in response time. The results suggest that explicit expectation of events and facilitation based on recent trial history have dissociable but competing effects on response performance. PMID:23972053

  14. The timing and magnitude of lake-level variability, in response to interannual climate variability

    NASA Astrophysics Data System (ADS)

    Huybers, K. M.; Rupper, S.; Roe, G.

    2013-12-01

    Some of the primary uncertainties and most critical consequences of both past and future climate change concern Earth's hydrological cycle. Lakes are key indicators of a region's hydrological cycle, directly reflecting the basin-wide balance between evaporation and precipitation. Lake-level records can therefore hold valuable information about the history of these climate variables. However, the interpretation of such records is not necessarily straightforward; because lakes integrate year-to-year climate fluctuations they will exhibit persistent fluctuations on timescales of decades or more. Any system with 'memory' (i.e., inertia, or a dynamic response time) will produce similar behavior. This inertia can make it difficult to distinguish lake-level fluctuations in response to stochastic climate forcing from a true shift in the climate -- a change in the mean or standard deviation of one or several climatic variables. The size and shape of a lake determines the response time to both stochastic forcing and climatic change, meaning that each individual lake will respond with a unique timescale and magnitude. We develop a general lake-level model to constrain a lake's response to interannual climate fluctuations. Because of its long historical lake-level and climatological records, we use the Great Salt Lake as a case-study for this work. We use mass-balance models to track the lake's response to synthetic, random time series of precipitation and evaporation, then compare the magnitude and frequency of our model's response to the historical record of the Great Salt Lake's rise and fall. We then compare simplified geometric representations of several lakes to illustrate how the timing and amplitude of a lake's response differs under unique climatic and geometric scenarios. We find that interannual climate variability alone can explain much of the decadal-centennial variations in the lake-level record. It is only after removing this background variability that a lake

  15. Molecular response properties from a Hermitian eigenvalue equation for a time-periodic Hamiltonian

    NASA Astrophysics Data System (ADS)

    Pawłowski, Filip; Olsen, Jeppe; Jørgensen, Poul

    2015-03-01

    The time-dependent Schrödinger equation for a time-periodic perturbation is recasted into a Hermitian eigenvalue equation, where the quasi-energy is an eigenvalue and the time-periodic regular wave function an eigenstate. From this Hermitian eigenvalue equation, a rigorous and transparent formulation of response function theory is developed where (i) molecular properties are defined as derivatives of the quasi-energy with respect to perturbation strengths, (ii) the quasi-energy can be determined from the time-periodic regular wave function using a variational principle or via projection, and (iii) the parametrization of the unperturbed state can differ from the parametrization of the time evolution of this state. This development brings the definition of molecular properties and their determination on par for static and time-periodic perturbations and removes inaccuracies and inconsistencies of previous response function theory formulations. The development where the parametrization of the unperturbed state and its time evolution may differ also extends the range of the wave function models for which response functions can be determined. The simplicity and universality of the presented formulation is illustrated by applying it to the configuration interaction (CI) and the coupled cluster (CC) wave function models and by introducing a new model—the coupled cluster configuration interaction (CC-CI) model—where a coupled cluster exponential parametrization is used for the unperturbed state and a linear parametrization for its time evolution. For static perturbations, the CC-CI response functions are shown to be the analytical analogues of the static molecular properties obtained from finite field equation-of-motion coupled cluster (EOMCC) energy calculations. The structural similarities and differences between the CI, CC, and CC-CI response functions are also discussed with emphasis on linear versus non-linear parametrizations and the size-extensivity of the

  16. Masked Morphological Priming in German-Speaking Adults and Children: Evidence from Response Time Distributions

    PubMed Central

    Hasenäcker, Jana; Beyersmann, Elisabeth; Schroeder, Sascha

    2016-01-01

    In this study, we looked at masked morphological priming effects in German children and adults beyond mean response times by taking into account response time distributions. We conducted an experiment comparing suffixed word primes (kleidchen-KLEID), suffixed nonword primes (kleidtum-KLEID), nonsuffixed nonword primes (kleidekt-KLEID), and unrelated controls (träumerei-KLEID). The pattern of priming in adults showed facilitation from suffixed words, suffixed nonwords, and nonsuffixed nonwords relative to unrelated controls, and from both suffixed conditions relative to nonsuffixed nonwords, thus providing evidence for morpho-orthographic and embedded stem priming. Children also showed facilitation from real suffixed words, suffixed nonwords, and nonsuffixed nonwords compared to unrelated words, but no difference between the suffixed and nonsuffixed conditions, thus suggesting that German elementary school children do not make use of morpho-orthographic segmentation. Interestingly, for all priming effects, a shift of the response time distribution was observed. Consequences for theories of morphological processing are discussed. PMID:27445899

  17. Response time effects of alerting tone and semantic context for synthesized voice cockpit warnings

    NASA Technical Reports Server (NTRS)

    Simpson, C. A.; Williams, D. H.

    1980-01-01

    Some handbooks and human factors design guides have recommended that a voice warning should be preceded by a tone to attract attention to the warning. As far as can be determined from a search of the literature, no experimental evidence supporting this exists. A fixed-base simulator flown by airline pilots was used to test the hypothesis that the total 'system-time' to respond to a synthesized voice cockpit warning would be longer when the message was preceded by a tone because the voice itself was expected to perform both the alerting and the information transfer functions. The simulation included realistic ATC radio voice communications, synthesized engine noise, cockpit conversation, and realistic flight routes. The effect of a tone before a voice warning was to lengthen response time; that is, responses were slower with an alerting tone. Lengthening the voice warning with another work, however, did not increase response time.

  18. Masked Morphological Priming in German-Speaking Adults and Children: Evidence from Response Time Distributions.

    PubMed

    Hasenäcker, Jana; Beyersmann, Elisabeth; Schroeder, Sascha

    2016-01-01

    In this study, we looked at masked morphological priming effects in German children and adults beyond mean response times by taking into account response time distributions. We conducted an experiment comparing suffixed word primes (kleidchen-KLEID), suffixed nonword primes (kleidtum-KLEID), nonsuffixed nonword primes (kleidekt-KLEID), and unrelated controls (träumerei-KLEID). The pattern of priming in adults showed facilitation from suffixed words, suffixed nonwords, and nonsuffixed nonwords relative to unrelated controls, and from both suffixed conditions relative to nonsuffixed nonwords, thus providing evidence for morpho-orthographic and embedded stem priming. Children also showed facilitation from real suffixed words, suffixed nonwords, and nonsuffixed nonwords compared to unrelated words, but no difference between the suffixed and nonsuffixed conditions, thus suggesting that German elementary school children do not make use of morpho-orthographic segmentation. Interestingly, for all priming effects, a shift of the response time distribution was observed. Consequences for theories of morphological processing are discussed. PMID:27445899

  19. Optimum Design of a Passive Suspension System of a Vehicle Subjected to Actual Random Road Excitations

    NASA Astrophysics Data System (ADS)

    Tamboli, J. A.; Joshi, S. G.

    1999-01-01

    Vehicles are subjected to random excitation due to road unevenness and variable velocity. In most research work reported earlier, the response analysis for Mean Square Acceleration Response (MSAR) has been carried out by considering the power spectral density (PSD) of the road excitation as white noise, and the velocity of the vehicle as constant. However, in the present paper the PSD of the actual road excitation has been found to follow an approximately exponentially decreasing curve. Also the change in vehicle velocity has a significant effect on the values of Root Mean Square Acceleration Response (RMSAR). Therefore, in this work, the RMSAR of a vehicle dynamic system subjected to actual random road excitations is obtained so as to account for the effect of the actual PSD of road excitation and the frequent changes in vehicle velocity. The RMSAR of the vehicle is calculated for actual field excitation using the Fast Fourier Transformation (FFT) technique to obtain the PSD, by recording observations at the rear wheel. The effect of time lag due to wheelbase on the RMSAR of the vehicle is studied. For this purpose, a new ratio α(τ) has been introduced. The relationship between α(τ) and the autocorrelation has been formulated. This ratio is useful for considering the effect of time lag due to wheelbase on RMSAR. Similarly, the effect of vehicle velocity on the RMSAR is obtained.Further, from a ride comfort point of view, the values of the design variables like spring stiffness and viscous damping coefficient of the front and rear suspensions have been obtained, by minimising the RMSAR using the desired boundary values of the vertical RMSAR as specified in the chart of ISO 2631, 1985(E) [1].

  20. Indicial response approach derived from Navier-Stokes equations. Part 1: Time-invariant equilibrium state

    NASA Technical Reports Server (NTRS)

    Truong, K. V.; Tobak, M.

    1990-01-01

    The indicial response approach is recast in a form appropriate to the study of vortex induced oscillations phenomena. An appropriate form is demonstrated for the indicial response of the velocity field which may be derived directly from the Navier-Stokes equations. On the basis of the Navier-Stokes equations, it is demonstrated how a form of the velocity response to an arbitrary motion may be determined. To establish its connection with the previous work, the new approach is applied first to the simple situation wherein the indicial response has a time invariant equilibrium state. Results for the aerodynamic response to an arbitrary motion are shown to confirm to the form obtained previously.

  1. Rate and timing of cortical responses driven by separate sensory channels

    PubMed Central

    Saal, Hannes P; Harvey, Michael A; Bensmaia, Sliman J

    2015-01-01

    The sense of touch comprises multiple sensory channels that each conveys characteristic signals during interactions with objects. These neural signals must then be integrated in such a way that behaviorally relevant information about the objects is preserved. To understand the process of integration, we implement a simple computational model that describes how the responses of neurons in somatosensory cortex—recorded from awake, behaving monkeys—are shaped by the peripheral input, reconstructed using simulations of neuronal populations that reproduce natural spiking responses in the nerve with millisecond precision. First, we find that the strength of cortical responses is driven by one population of nerve fibers (rapidly adapting) whereas the timing of cortical responses is shaped by the other (Pacinian). Second, we show that input from these sensory channels is integrated in an optimal fashion that exploits the disparate response behaviors of different fiber types. DOI: http://dx.doi.org/10.7554/eLife.10450.001 PMID:26650354

  2. Time reallocation in a multiresponse environment: Effects of restricting response classes

    PubMed Central

    Lyons, Charles A.; Cheney, Carl D.

    1984-01-01

    Four adult male rats were each placed for three hours daily into an apparatus that provided individual compartments for six separate location-defined responses. The available responses consisted of: (1) the opportunity to turn off room lighting, producing darkness; (2) the opportunity to view a female rat; (3) the opportunity to turn off white noise; (4) the opportunity to drink; (5) the opportunity to eat; and (6) “other,” representing time in the hallway between compartments. Each subject underwent a series of conditions characterized as an A-B-A-C-A design. Manipulations consisted of the removal of a low-probability response (darkness) and of a high-probability response (escape from noise) in a counter-balanced manner across subjects. The dependent measure for all subjects was the percentage of total session time spent in each compartment. Four predictive rules concerning the redistribution of behavior after response restriction were tested, including the constant-ratio rule, equal time redistribution, the most probable alternative, and the sequential-dependency rule. The results indicate no support for any of the four predictive rules and suggest that empirical assessment of restriction effects is necessary in reinforcement studies involving temporally extended responses. PMID:16812370

  3. Design oriented identification of critical times in transient response. [due to dynamic loads

    NASA Technical Reports Server (NTRS)

    Haftka, R. T.; Watson, L. T.; Grandhi, R. V.

    1984-01-01

    Two techniques are presented for reducing the computational effort in identifying the critical time points. One approach is an adaptive search technique, well suited for the case where the response is exactly known. The other technique, useful for noisy response, is based on a least-squares spline approximation of the response. The possibility of grouping several closely spaced local peaks to identify a single super peak from each group is also investigated. The computational efficiency of the techniques proposed here is illustrated by two examples.

  4. Simulations of hybrid system varying solar radiation and microturbine response time

    SciTech Connect

    Fernández Ribaya, Yolanda Álvarez, Eduardo; Paredes Sánchez, José Pablo; Xiberta Bernat, Jorge

    2015-07-15

    Hybrid power systems, such as combinations of renewable power sources with intermittent power production and non-renewable power sources, theoretically increase the reliability and thus integration of renewable sources in the electrical system. However, a recent increase in the number of hybrid installations has sparked interest in the effects of their connection to the grid, especially in remote areas. This paper analyses a photovoltaic-gas microturbine hybrid system dimensioned to be installed in La Paz (Mexico).The research presented in this paper studies and quantifies the effects on the total electric power produced, varying both the solar radiation and the gas microturbine response time. The gas microturbine and the photovoltaic panels are modelled using Matlab/Simulink software, obtaining a platform where different tests to simulate real conditions have been executed. They consist of diverse ramps of irradiance that replicate solar radiation variations, and different microturbine response times reproduced by the time constants of a first order transfer function that models the microturbine dynamic response. The results obtained show that when radiation varies quickly it does not produce significant differences in the power guarantee or the microturbine gas consumption, to any microturbine response time. However, these two parameters are highly variable with smooth radiance variations. The maximum total power variation decreases greatly as the radiation variation gets lower. In addition, by decreasing the microturbine response time, it is possible to appreciably increase the power guarantee although the maximum power variation and gas consumption increase. Only in cases of low radiation variation is there no appreciable difference in the maximum power variation obtained by the different turbine response times.

  5. Simulations of hybrid system varying solar radiation and microturbine response time

    NASA Astrophysics Data System (ADS)

    Fernández Ribaya, Yolanda; Álvarez, Eduardo; Paredes Sánchez, José Pablo; Xiberta Bernat, Jorge

    2015-07-01

    Hybrid power systems, such as combinations of renewable power sources with intermittent power production and non-renewable power sources, theoretically increase the reliability and thus integration of renewable sources in the electrical system. However, a recent increase in the number of hybrid installations has sparked interest in the effects of their connection to the grid, especially in remote areas. This paper analyses a photovoltaic-gas microturbine hybrid system dimensioned to be installed in La Paz (Mexico).The research presented in this paper studies and quantifies the effects on the total electric power produced, varying both the solar radiation and the gas microturbine response time. The gas microturbine and the photovoltaic panels are modelled using Matlab/Simulink software, obtaining a platform where different tests to simulate real conditions have been executed. They consist of diverse ramps of irradiance that replicate solar radiation variations, and different microturbine response times reproduced by the time constants of a first order transfer function that models the microturbine dynamic response. The results obtained show that when radiation varies quickly it does not produce significant differences in the power guarantee or the microturbine gas consumption, to any microturbine response time. However, these two parameters are highly variable with smooth radiance variations. The maximum total power variation decreases greatly as the radiation variation gets lower. In addition, by decreasing the microturbine response time, it is possible to appreciably increase the power guarantee although the maximum power variation and gas consumption increase. Only in cases of low radiation variation is there no appreciable difference in the maximum power variation obtained by the different turbine response times.

  6. Mucosal and systemic immune responses induced by a single time vaccination strategy in mice.

    PubMed

    González Aznar, Elizabeth; Romeu, Belkis; Lastre, Miriam; Zayas, Caridad; Cuello, Maribel; Cabrera, Osmir; Valdez, Yolanda; Fariñas, Mildrey; Pérez, Oliver

    2015-08-01

    Vaccination is considered by the World Health Organization as the most cost-effective strategy for controlling infectious diseases. In spite of great successes with vaccines, many infectious diseases are still leading killers, because of the inadequate coverage of many vaccines. Several factors have been responsible: number of doses, high vaccine reactogenicity, vaccine costs, vaccination policy, among others. Contradictorily, few vaccines are of single dose and even less of mucosal administration. However, more common infections occur via mucosa, where secretory immunoglobulin A plays an essential role. As an alternative, we proposed a novel protocol of vaccination called Single Time Vaccination Strategy (SinTimVaS) by immunizing 2 priming doses at the same time: one by mucosal route and the other by parenteral route. Here, the mucosal and systemic responses induced by Finlay adjuvants (AF Proteoliposome 1 and AF Cochleate 1) implementing SinTimVaS in BALB/c mice were evaluated. One intranasal dose of AF Cochleate 1 and an intramuscular dose of AF Proteoliposome 1 adsorbed onto aluminum hydroxide, with bovine serum albumin or tetanus toxoid as model antigens, administrated at the same time, induced potent specific mucosal and systemic immune responses. Also, we demonstrated that SinTimVaS using other mucosal routes like oral and sublingual, in combination with the subcutaneous route elicits immune responses. SinTimVaS, as a new immunization strategy, could increase vaccination coverage and reduce time-cost vaccines campaigns, adding the benefits of immune response in mucosa.

  7. On timing response improvement of an NE213 scintillator attached to two PMTs

    NASA Astrophysics Data System (ADS)

    Zare, S.; Ghal-Eh, N.; Bayat, E.

    2013-09-01

    A 5 cm diameter by 6 cm height NE213 scintillator attached to two XP2282 PHOTONIS photomultiplier tubes (PMTs) exposed to 241Americium-Berylium (Am-Be) neutron-gamma source has been used for timing response studies. The neutron-gamma discrimination (NGD) measurements based on a modified zero-crossing (ZC) method show that the discrimination quality, usually expressed in figure-of-merit (FoM) and peak-to-valley (P/V) values, has been improved. The timing response evaluated with Monte Carlo light transport code, PHOTRACK, also verifies this improvement.

  8. Dual-Frequency Addressed Variable Optical Attenuator with Submillisecond Response Time

    NASA Astrophysics Data System (ADS)

    Liang, Xiao; Lu, Yan-Qing; Wu, Yung-Hsun; Du, Fang; Wang, Hai-Ying; Wu, Shin-Tson

    2005-03-01

    We demonstrated a submillisecond response time and low-voltage variable optical attenuator (VOA) using a dual-frequency liquid crystal. The dynamic range of the VOA reaches 43 dB at a 1.55 μm wavelength. A normally on VOA with a flat wavelength response is obtained using a phase compensation cell. Fast rise and decay times are achieved using low-frequency overdrive and high-frequency undershoot voltages. Other approaches to further improve the VOA's performances are discussed.

  9. Time to smell: a cascade model of human olfactory perception based on response-time (RT) measurement.

    PubMed

    Olofsson, Jonas K

    2014-01-01

    The timing of olfactory behavioral decisions may provide an important source of information about how the human olfactory-perceptual system is organized. This review integrates results from olfactory response-time (RT) measurements from a perspective of mental chronometry. Based on these findings, a new cascade model of human olfaction is presented. Results show that main perceptual decisions are executed with high accuracy within about 1~s of sniff onset. The cascade model proposes the existence of distinct processing stages within this brief time-window. According to the cascade model, different perceptual features become accessible to the perceiver at different time-points, and the output of earlier processing stages provides the input for later processing stages. The olfactory cascade starts with detecting the odor, which is followed by establishing an odor object. The odor object, in turn, triggers systems for determining odor valence and edibility. Evidence for the cascade model comes from studies showing that RTs for odor valence and edibility assessment are predicted by the shorter RTs needed to establish the odor object. Challenges for future research include innovative task designs for olfactory RT experiments and the integration of the behavioral processing sequence into the underlying cortical processes using complementary RT measures and neuroimaging methods.

  10. A national census of ambulance response times to emergency calls in Ireland

    PubMed Central

    Breen, N.; Woods, J.; Bury, G.; Murphy, A.; Brazier, H.

    2000-01-01

    Background—Equity of access to appropriate pre-hospital emergency care is a core principle underlying an effective ambulance service. Care must be provided within a timeframe in which it is likely to be effective. A national census of response times to emergency and urgent calls in statutory ambulance services in Ireland was undertaken to assess current service provision. Methods—A prospective census of response times to all emergency and urgent calls was carried out in the nine ambulance services in the country over a period of one week. The times for call receipt, activation, arrival at and departure from scene and arrival at hospital were analysed. Crew type, location of call and distance from ambulance base were detailed. The type of incident leading to the call was recorded but no further clinical information was gathered. Results—2426 emergency calls were received by the services during the week. Fourteen per cent took five minutes or longer to activate (range 5–33%). Thirty eight per cent of emergencies received a response within nine minutes (range 10–47%). Only 4.5% of emergency calls originating greater than five miles from an ambulance station were responded to within nine minutes (range 0–10%). Median patient care times for "on call" crews were three times longer than "on duty" crews. Conclusion—Without prioritised use of available resources, inappropriately delayed responses to critical incidents will continue. Recommendations are made to improve the effectiveness of emergency medical service utilisation. PMID:11104237

  11. Thermal dose and time-temperature factors for biological responses to heat shock.

    PubMed

    Gerner, E W

    1987-01-01

    The application of hyperthermia in human cancer therapy, especially by radiotherapists who are accustomed to prescribing ionizing radiation treatments in physical dose units, has stimulated workers in this area to consider the possibility and utility of defining a unit of 'thermal dose'. Previous thermal dose definitions have, primarily, been based on biological isoeffect response relationships, which attempt to relate exposure times that elicit a given biological response at one temperature to exposure times at another temperature that elicit the same biological response. This 'equivalent time' method is shown to have certain limitations. For both 42.4 and 45 degrees C hyperthermia, these relationships accurately describe cell survival responses only when the heating rate is rapid (greater than 0.5 degrees C min-1 from ambient to hyperthermic temperature). Further, the form of these isoeffect relationships appears to be temperature range and cell/tissue-type dependent, and it is suggested that these relationships be referred to as a 'time-temperature factor' (TTF) to help distinguish them from possible physical thermal dose definitions. Two physical dose definitions are discussed, one being simply exposure time at some temperature and the other being a more fundamental definition, the free energy change which is a temperature-dependent driving force for chemical reactions.

  12. Brain Activations Related to Saccadic Response Conflict are not Sensitive to Time on Task

    PubMed Central

    Beldzik, Ewa; Domagalik, Aleksandra; Oginska, Halszka; Marek, Tadeusz; Fafrowicz, Magdalena

    2015-01-01

    Establishing a role of the dorsal medial frontal cortex in the performance monitoring and cognitive control has been a challenge to neuroscientists for the past decade. In light of recent findings, the conflict monitoring hypothesis has been elaborated to an action-outcome predictor theory. One of the findings that led to this re-evaluation was the fMRI study in which conflict-related brain activity was investigated in terms of the so-called time on task effect, i.e., a linear increase of the BOLD signal with longer response times. The aim of this study was to investigate brain regions involved in the processing of saccadic response conflict and to account for the time on task effect. A modified spatial cueing task was implemented in the event-related fMRI study with oculomotor responses. The results revealed several brain regions which show higher activity for incongruent trials in comparison to the congruent ones, including pre-supplementary motor area together with the frontal and parietal regions. Further analysis accounting for the effect of response time provided evidence that these brain activations were not sensitive to time on task but reflected purely the congruency effect. PMID:26696871

  13. The contribution of pre-stimulus neural oscillatory activity to spontaneous response time variability

    PubMed Central

    Bompas, Aline; Sumner, Petroc; Muthumumaraswamy, Suresh D.; Singh, Krish D.; Gilchrist, Iain D.

    2015-01-01

    Large variability between individual response times, even in identical conditions, is a ubiquitous property of animal behavior. However, the origins of this stochasticity and its relation to action decisions remain unclear. Here we focus on the state of the perception–action network in the pre-stimulus period and its influence on subsequent saccadic response time and choice in humans. We employ magnetoencephalography (MEG) and a correlational source reconstruction approach to identify the brain areas where pre-stimulus oscillatory activity predicted saccadic response time to visual targets. We find a relationship between future response time and pre-stimulus power, but not phase, in occipital (including V1), parietal, posterior cingulate and superior frontal cortices, consistently across alpha, beta and low gamma frequencies, each accounting for between 1 and 4% of the RT variance. Importantly, these correlations were not explained by deterministic sources of variance, such as experimental factors and trial history. Our results further suggest that occipital areas mainly reflect short-term (trial to trial) stochastic fluctuations, while the frontal contribution largely reflects longer-term effects such as fatigue or practice. Parietal areas reflect fluctuations at both time scales. We found no evidence of lateralization: these effects were indistinguishable in both hemispheres and for both saccade directions, and non-predictive of choice — a finding with fundamental consequences for models of action decision, where independent, not coupled, noise is normally assumed. PMID:25482267

  14. Representing Response-Time Information in Item Banks. Law School Admission Council Computerized Testing Report. LSAC Research Report Series.

    ERIC Educational Resources Information Center

    Schnipke, Deborah L.; Scrams, David J.

    The availability of item response times made possible by computerized testing represents an entirely new type of information about test items. This study explores the issue of how to represent response-time information in item banks. Empirical response-time distribution functions can be fit with statistical distribution functions with known…

  15. Subjective response to sonic booms having different shapes, rise times, and durations

    NASA Technical Reports Server (NTRS)

    Mccurdy, David A.

    1994-01-01

    Two laboratory experiments were conducted to quantify the subjective response of people to simulated outdoor sonic booms having different pressure signatures. The specific objectives of the experiments were to compare subjective response to sonic booms when described in terms of 'loudness' and 'annoyance'; to determine the ability of various noise metrics to predict subjective response to sonic booms; to determine the effects on subjective response of rise time, duration, and level; and to compare the subjective response to 'N-wave' sonic boom signatures with the subjective response to 'minimized' sonic boom signatures. The experiments were conducted in a computer-controlled, man-rated sonic boom simulator capable of reproducing user-specified pressure signatures for a wide range of sonic boom parameters. One hundred and fifty sonic booms representing different combinations of two wave shapes, four rise times, seven durations, and three peak overpressures were presented to 36 test subjects in each experiment. The test subjects in the first experiment made judgments of 'loudness' while the test subjects in the second experiment judged 'annoyance.' Subjective response to sonic booms was the same whether expressed in terms of loudness or in terms of annoyance. Analyses of several different noise metrics indicated that A-weighted sound exposure level and Perceived Level were the best predictors of subjective response. Further analyses indicated that, of these two noise metrics, only Perceived Level completely accounted for the effects of wave shape, rise time, and peak overpressure. Neither metric fully accounted for the effect of duration. However, the magnitude of the duration effect was small over the very wide range of durations considered.

  16. Time-delay spectrometry measurement of magnitude and phase of hydrophone response.

    PubMed

    Wear, Keith A; Gammell, Paul M; Maruvada, Subha; Liu, Yunbo; Harris, Gerald R

    2011-11-01

    A method based on time-delay spectrometry (TDS) was developed for measuring both magnitude and phase response of a hydrophone. The method was tested on several types of hydrophones used in medical ultrasound exposimetry over the range from 5 to 18 MHz. These included polyvinylidene fluoride (PVDF) spot-poled membrane, needle, and capsule designs. One needle hydrophone was designed for high-intensity focused ultrasound (HIFU) applications. The average reproducibility (after repositioning the hydrophone) of the phase measurement was 2.4°. The minimum-phase model, which implies that the phase response is equal to the inverse Hilbert transform of the natural logarithm of the magnitude response, was tested with TDS hydrophone data. Direct TDS-based measurements of hydrophone phase responses agreed well with calculations based on the minimum-phase model, with rms differences of 1.76° (PVDF spot-poled membrane hydrophone), 3.10° (PVDF capsule hydrophone), 3.43° (PVDF needle hydrophone), and 3.36° (ceramic needle hydrophone) over the range from 5 to 18 MHz. Therefore, phase responses for several types of hydrophones may be inferred from measurements of their magnitude responses. Calculation of phase response based on magnitude response using the minimumphase model is a relatively simple and practical alternative to direct measurement of phase. PMID:22083766

  17. A New Thermostat for Real-Time Price Demand Response: Cost, Comfort and Energy Impacts of Discrete-Time Control without Deadband

    SciTech Connect

    Chassin, David P.; Stoustrup, Jakob; Agathoklis, Pan; Djilali, Ned

    2015-10-01

    This paper presents a residential thermostat design that enables accurate aggregate load control systems for electricity demand response. The thermostat features a control strategy that can be modeled as a linear time-invariant system for short- term demand response signals from the utility. This control design maintains the same comfort and demand response characteristics of existing real-time price- responsive thermostats but gives rise to linear time-invariant models of aggregate load control and demand response, which facilitates the design of highly accurate load-based regulation services for electricity interconnections.

  18. From rain to cave drip water: Hydraulic response time and water transfer time at Bunker Cave (NW Germany)

    NASA Astrophysics Data System (ADS)

    Riechelmann, Sylvia; Schröder-Ritzrau, Andrea; Spötl, Christoph; Riechelmann, Dana F. C.; Richter, Detlev K.; Mangini, Augusto; Frank, Norbert; Immenhauser, Adrian

    2016-04-01

    Speleothem based palaeoclimate studies considerably increased during the last two decades. Processes in the soil and karst zone influence the proxies applied on the speleothem climate archive. Thus, caves are monitored for a wide range of environmental parameters. These monitoring programmes mostly focus on seasonal variations but less so on the multi-annual time scale. The present study analyses long-term trends from a seven year-long monitoring of Bunker Cave, NW Germany, in order to assess the hydraulic response time and transfer time of meteoric water from the surface to the cave. Therefore, drip rates of all sites were measured manually with a stopwatch and rain, soil as well as drip waters were collected in a monthly to bimonthly resolution. Subsequently, the oxygen and hydrogen isotopic compositions of the waters were analysed. Furthermore, the coefficient of permeability was calculated from granulometric analyses performed on soil samples collected above Bunker Cave. The annual mean drip rates of all drip sites except one display the same long-term trend. In the case of Bunker Cave, correlations of the annual mean drip rate of each site with annual precipitation and infiltration demonstrate that the annual infiltration and thus, the annual precipitation control the interannual drip-rate variability. Therefore, the hydraulic response time does not show a temporal offset. The annual mean oxygen isotopic compositions of all drip waters except one display the same long-term trend, whilst the annual mean hydrogen isotope ratios of all drip sites display the same trend. In combination with the results of the coefficient of permeability, correlations of soil and drip water annual mean oxygen and hydrogen isotopic composition with atmospheric temperature reveal water transfer times for soil water of 3 to 6 months for 40 cm soil-depth and ca. 1 year for 70 cm soil-depth. Finally, the water reaches the cave after three years transfer time. As a consequence, a

  19. Dynamic response of the Initial Systolic Time Interval to a breathing stimulus measured with impedance cardiography

    NASA Astrophysics Data System (ADS)

    Meijer, Jan H.; Hoekstra, Femke; Habers, Esther; Verdaasdonk, Ruud M.; Janssen, Thomas W. J.

    2010-04-01

    The Initial Systolic Time Interval (ISTI) is a measure for the time delay between the electrical and mechanical activity of the heart. The present study reports about the dynamic response of ISTI to a Valsalva manoeuvre. This response was investigated in 22 young healthy volunteers, having different levels of training in sports. The time course of the ISTI during the Valsalva manoeuvre was found to follow a distinct pattern and to be analogous to the course of the Pre-Ejection Period (PEP), also obtained from ECG and ICG signals, reported earlier. The recordings show a definite influence of the Frank-Starling mechanism and are to some extent consistent with reports on the time course of sympathetic activation. The highly trained subjects showed an ISTI that was systematically longer at all moments of the manoeuvre.

  20. Detecting variable responses in time-series using repeated measures ANOVA: Application to physiologic challenges

    PubMed Central

    Macey, Paul M.; Schluter, Philip J.; Macey, Katherine E.; Harper, Ronald M.

    2016-01-01

    We present an approach to analyzing physiologic timetrends recorded during a stimulus by comparing means at each time point using repeated measures analysis of variance (RMANOVA). The approach allows temporal patterns to be examined without an a priori model of expected timing or pattern of response. The approach was originally applied to signals recorded from functional magnetic resonance imaging (fMRI) volumes-of-interest (VOI) during a physiologic challenge, but we have used the same technique to analyze continuous recordings of other physiological signals such as heart rate, breathing rate, and pulse oximetry. For fMRI, the method serves as a complement to whole-brain voxel-based analyses, and is useful for detecting complex responses within pre-determined brain regions, or as a post-hoc analysis of regions of interest identified by whole-brain assessments. We illustrate an implementation of the technique in the statistical software packages R and SAS. VOI timetrends are extracted from conventionally preprocessed fMRI images. A timetrend of average signal intensity across the VOI during the scanning period is calculated for each subject. The values are scaled relative to baseline periods, and time points are binned. In SAS, the procedure PROC MIXED implements the RMANOVA in a single step. In R, we present one option for implementing RMANOVA with the mixed model function “lme”. Model diagnostics, and predicted means and differences are best performed with additional libraries and commands in R; we present one example. The ensuing results allow determination of significant overall effects, and time-point specific within- and between-group responses relative to baseline. We illustrate the technique using fMRI data from two groups of subjects who underwent a respiratory challenge. RMANOVA allows insight into the timing of responses and response differences between groups, and so is suited to physiologic testing paradigms eliciting complex response patterns.

  1. Detecting variable responses in time-series using repeated measures ANOVA: Application to physiologic challenges.

    PubMed

    Macey, Paul M; Schluter, Philip J; Macey, Katherine E; Harper, Ronald M

    2016-01-01

    We present an approach to analyzing physiologic timetrends recorded during a stimulus by comparing means at each time point using repeated measures analysis of variance (RMANOVA). The approach allows temporal patterns to be examined without an a priori model of expected timing or pattern of response. The approach was originally applied to signals recorded from functional magnetic resonance imaging (fMRI) volumes-of-interest (VOI) during a physiologic challenge, but we have used the same technique to analyze continuous recordings of other physiological signals such as heart rate, breathing rate, and pulse oximetry. For fMRI, the method serves as a complement to whole-brain voxel-based analyses, and is useful for detecting complex responses within pre-determined brain regions, or as a post-hoc analysis of regions of interest identified by whole-brain assessments. We illustrate an implementation of the technique in the statistical software packages R and SAS. VOI timetrends are extracted from conventionally preprocessed fMRI images. A timetrend of average signal intensity across the VOI during the scanning period is calculated for each subject. The values are scaled relative to baseline periods, and time points are binned. In SAS, the procedure PROC MIXED implements the RMANOVA in a single step. In R, we present one option for implementing RMANOVA with the mixed model function "lme". Model diagnostics, and predicted means and differences are best performed with additional libraries and commands in R; we present one example. The ensuing results allow determination of significant overall effects, and time-point specific within- and between-group responses relative to baseline. We illustrate the technique using fMRI data from two groups of subjects who underwent a respiratory challenge. RMANOVA allows insight into the timing of responses and response differences between groups, and so is suited to physiologic testing paradigms eliciting complex response patterns.

  2. Detecting variable responses in time-series using repeated measures ANOVA: Application to physiologic challenges

    PubMed Central

    Macey, Paul M.; Schluter, Philip J.; Macey, Katherine E.; Harper, Ronald M.

    2016-01-01

    We present an approach to analyzing physiologic timetrends recorded during a stimulus by comparing means at each time point using repeated measures analysis of variance (RMANOVA). The approach allows temporal patterns to be examined without an a priori model of expected timing or pattern of response. The approach was originally applied to signals recorded from functional magnetic resonance imaging (fMRI) volumes-of-interest (VOI) during a physiologic challenge, but we have used the same technique to analyze continuous recordings of other physiological signals such as heart rate, breathing rate, and pulse oximetry. For fMRI, the method serves as a complement to whole-brain voxel-based analyses, and is useful for detecting complex responses within pre-determined brain regions, or as a post-hoc analysis of regions of interest identified by whole-brain assessments. We illustrate an implementation of the technique in the statistical software packages R and SAS. VOI timetrends are extracted from conventionally preprocessed fMRI images. A timetrend of average signal intensity across the VOI during the scanning period is calculated for each subject. The values are scaled relative to baseline periods, and time points are binned. In SAS, the procedure PROC MIXED implements the RMANOVA in a single step. In R, we present one option for implementing RMANOVA with the mixed model function “lme”. Model diagnostics, and predicted means and differences are best performed with additional libraries and commands in R; we present one example. The ensuing results allow determination of significant overall effects, and time-point specific within- and between-group responses relative to baseline. We illustrate the technique using fMRI data from two groups of subjects who underwent a respiratory challenge. RMANOVA allows insight into the timing of responses and response differences between groups, and so is suited to physiologic testing paradigms eliciting complex response patterns

  3. Detecting variable responses in time-series using repeated measures ANOVA: Application to physiologic challenges.

    PubMed

    Macey, Paul M; Schluter, Philip J; Macey, Katherine E; Harper, Ronald M

    2016-01-01

    We present an approach to analyzing physiologic timetrends recorded during a stimulus by comparing means at each time point using repeated measures analysis of variance (RMANOVA). The approach allows temporal patterns to be examined without an a priori model of expected timing or pattern of response. The approach was originally applied to signals recorded from functional magnetic resonance imaging (fMRI) volumes-of-interest (VOI) during a physiologic challenge, but we have used the same technique to analyze continuous recordings of other physiological signals such as heart rate, breathing rate, and pulse oximetry. For fMRI, the method serves as a complement to whole-brain voxel-based analyses, and is useful for detecting complex responses within pre-determined brain regions, or as a post-hoc analysis of regions of interest identified by whole-brain assessments. We illustrate an implementation of the technique in the statistical software packages R and SAS. VOI timetrends are extracted from conventionally preprocessed fMRI images. A timetrend of average signal intensity across the VOI during the scanning period is calculated for each subject. The values are scaled relative to baseline periods, and time points are binned. In SAS, the procedure PROC MIXED implements the RMANOVA in a single step. In R, we present one option for implementing RMANOVA with the mixed model function "lme". Model diagnostics, and predicted means and differences are best performed with additional libraries and commands in R; we present one example. The ensuing results allow determination of significant overall effects, and time-point specific within- and between-group responses relative to baseline. We illustrate the technique using fMRI data from two groups of subjects who underwent a respiratory challenge. RMANOVA allows insight into the timing of responses and response differences between groups, and so is suited to physiologic testing paradigms eliciting complex response patterns. PMID

  4. Superposed epoch analysis of storm time response of the ionosphere-thermosphere (IT) system

    NASA Astrophysics Data System (ADS)

    Oliveira, D. M.; Zesta, E.; Connor, H.; Su, Y. J.; Sutton, E. K.; Huang, C. Y.; Ober, D. M.; Delay, S. H.; Schuck, P. W.

    2015-12-01

    The thermosphere-ionosphere system response to energy input by Joule heating via Poynting flux and auroral precipitation is strongly intensified during times with high geomagnetic activity or during geomagnetic storms. The most dramatic thermospheric response is the intensification and upwelling of the thermospheric mass density. The neutral mass density is not only a key parameter to understanding the solar wind - IT coupling, but also plays an important role in understanding satellite orbital drag, which in turn impacts satellite position predictions. Results of numerical simulations and satellite observations (CHAMP and GRACE) have shown that the neutral mass density is rapidly intensified (within minutes) after the initial storm shock impact and also after the onset of storm main phase. This almost immediate response is typical of CME-driven storms in which the neutral density is enhanced first in the dayside polar cap and the intensification subsequently spreads out to all magnetic local time regions and lower latitude regions. We perform a superposed epoch analysis using CHAMP and GRACE satellite data as well as DMSP data to study the spatial and temporal distribution of the measured Poynting flux and neutral density response during the main phase of storms of different intensity. We also examine the correlation characteristics between Poynting flux and neutral density response, in space and time during the storm.

  5. Real-time QCM-D monitoring of cellular responses to different cytomorphic agents.

    PubMed

    Fatisson, Julien; Azari, Fereshteh; Tufenkji, Nathalie

    2011-03-15

    Quartz crystal microbalance with dissipation monitoring (QCM-D) is used for real-time in situ detection of cytoskeletal changes in live primary endothelial cells in response to different cytomorphic agents; namely, the surfactant Triton-X 100 (TX-100) and bacterial lipopolysaccharide (LPS). Reproducible dissipation versus frequency (Df) plots provide unique signatures of the interactions between endothelial cells and cytomorphic agents. While the QCM-D response for TX-100 can be described in two steps (changes in the osmotic pressure of the medium prior to observing the expected cell lysis), LPS results in a different single-phase signal. A complementary analysis is carried out to evaluate the possible competitive effects of TX-100 and LPS through the QCM-D response to BAEC stress by analyzing the Df plots obtained. Experiments with non-toxic components (fibronectin or serum) produce a different QCM-D response than that observed for the toxic chemicals, suggesting the use of Df plot signatures for the possible differentiation between cytotoxic or non-cytotoxic effects. Observations obtained by QCM-D signals are confirmed by conducting fluorescence microscopy at the same time. Our results show that a fast (few minutes) sensing response can be obtained in situ and in real-time. The conclusions from this study suggest that QCM-D can potentially be used in biodetection for applications in drug screening tests and diagnosis. PMID:21237634

  6. Models Of Lower Extremity Damage In Mice: Time Course of Organ Damage & Immune Response

    PubMed Central

    Menzel, Christoph L; Pfeifer, Roman; Darwiche, Sophie S; Kobbe, Philipp; Gill, Roop; Shapiro, Richard A; Loughran, Patricia; Vodovotz, Yoram; Scott, Melanie J; Zenati, Mazen S; Billiar, Timothy R; Pape, Hans-Christoph

    2011-01-01

    Background Posttraumatic inflammatory changes have been identified as major causes of altered organ function and failure. Both hemorrhage and soft tissue damage induce these inflammatory changes. Exposure to heterologous bone in animal models has recently been shown to mimic this inflammatory response in a stable and reproducible fashion. This follow-up study tests the hypothesis that inflammatory responses are comparable between a novel trauma model (“pseudofracture”, PFx) and a bilateral femur fracture (BFF) model. Materials and Methods In C57BL/6 mice, markers for remote organ dysfunction and inflammatory responses were compared in 4 groups (control/sham/BFF/PFx) at the time points 2, 4, and 6 hours. Results Hepatocellular damage in BFF and PFx was highly comparable in extent and evolution, as shown by similar levels of NFκB activation and plasma ALT. Pulmonary inflammatory responses were also comparably elevated in both trauma models as early as 2h after trauma as measured by myeloperoxidase activity (MPO). Muscle damage was provoked in both BFF and PFx mice over the time course, although BFF induced significantly higher AST and CK levels. IL-6 levels were also similar with early and sustained increases over time in both trauma models. Conclusions Both BFF and PFx create similar reproducible inflammatory and remote organ responses. PFx will be a useful model to study longer term inflammatory effects that cannot be studied using BFF. PMID:21276982

  7. Rise time and response measurements on a LiSOCl2 cell

    NASA Technical Reports Server (NTRS)

    Bastien, Caroline; Lecomte, Eric J.

    1992-01-01

    Dynamic impedance tests were performed on a 180 Ah LiSOCl2 cell in the frame of a short term work contract awarded by Aerospatiale as part of the Hermes Space Plane development work. These tests consisted of rise time and response measurements. The rise time test was performed to show the ability to deliver 4 KW, in the nominal voltage range (75-115 V), within less than 100 microseconds, and after a period at rest of 13 days. The response measurements test consisted of step response and frequency response tests. The frequency response test was performed to characterize the response of the LiSOCl2 cell to a positive or negative load step of 10 A starting from various currents. The test was performed for various depths of discharge and various temperatures. The test results were used to build a mathematical, electrical model of the LiSOCl2 cell which are also presented. The test description, test results, electrical modelization description, and conclusions are presented.

  8. Time course of vasodilatory responses in skeletal muscle arterioles: role in hyperemia at onset of exercise

    NASA Technical Reports Server (NTRS)

    Wunsch, S. A.; Muller-Delp, J.; Delp, M. D.

    2000-01-01

    At the onset of dynamic exercise, muscle blood flow increases within 1-2 s. It has been postulated that local vasodilatory agents produced by the vascular endothelium or the muscle itself contribute to this response. We hypothesized that only vasodilators that act directly on the vascular smooth muscle could produce vasodilation of skeletal muscle arterioles in <2 s. To test this hypothesis, we determined the time course of the vasodilatory response of isolated skeletal muscle arterioles to direct application of potassium chloride, adenosine, acetylcholine, and sodium nitroprusside. Soleus and gastrocnemius muscles were dissected from the hindlimbs of male Sprague-Dawley rats. First-order arterioles (100-200 microm) were isolated, cannulated on micropipettes, and pressurized to 60 cmH(2)O in an organ bath. Vasodilatory agents were added directly to the bath, and diameter responses of the arterioles were recorded in real time on a videotape recorder. Frame-by-frame analysis of the diameter responses indicated that none of the vasodilator agents tested produced significant diameter increases in <4 s in either soleus or gastrocnemius muscle arterioles. These results indicate that, although these local vasodilators produce significant vasodilation of skeletal muscle resistance arterioles, these responses are not rapid enough (within 1-2 s) to contribute to the initiation of the exercise hyperemic response at the onset of dynamic exercise.

  9. The Effect of Intervention on Accuracy of Students' Responses and Reaction Times to Geometry Problems

    ERIC Educational Resources Information Center

    Babai, Reuven; Zilber, Hanna; Stavy, Ruth; Tirosh, Dina

    2010-01-01

    This study investigates the effect on student performance in drawing their attention to relevant task variables, focusing on accuracy of responses and reaction times. We chose this methodology in order to better understand how such interventions affect the reasoning process. The study employs a geometry task in which the irrelevant salient…

  10. Semiparametric Estimation of Treatment Effect with Time-Lagged Response in the Presence of Informative Censoring

    PubMed Central

    Lu, Xiaomin; Tsiatis, Anastasios A.

    2011-01-01

    In many randomized clinical trials, the primary response variable, for example, the survival time, is not observed directly after the patients enroll in the study but rather observed after some period of time (lag time). It is often the case that such a response variable is missing for some patients due to censoring that occurs when the study ends before the patient’s response is observed or when the patients drop out of the study. It is often assumed that censoring occurs at random which is referred to as noninformative censoring; however, in many cases such an assumption may not be reasonable. If the missing data are not analyzed properly, the estimator or test for the treatment effect may be biased. In this paper, we use semiparametric theory to derive a class of consistent and asymptotically normal estimators for the treatment effect parameter which are applicable when the response variable is right censored. The baseline auxiliary covariates and post-treatment auxiliary covariates, which may be time-dependent, are also considered in our semiparametric model. These auxiliary covariates are used to derive estimators that both account for informative censoring and are more efficient then the estimators which do not consider the auxiliary covariates. PMID:21706378

  11. Intermolecular forces and nonbonded interactions: Superoperator nonlinear time-dependent density-functional-theory response approach

    SciTech Connect

    Harbola, Upendra; Mukamel, Shaul

    2004-11-01

    Electrostatic and dispersive interactions of polarizable molecules are expressed in terms of generalized (nonretarded) charge-density response functions of the isolated molecules, which in turn are expanded using the collective electronic oscillator (CEO) eigenmodes of linearized time-dependent density-functional theory. Closed expressions for the intermolecular energy are derived to sixth order in charge fluctuation amplitudes.

  12. Additive and Interactive Effects on Response Time Distributions in Visual Word Recognition

    ERIC Educational Resources Information Center

    Yap, Melvin J.; Balota, David A.

    2007-01-01

    Across 3 different word recognition tasks, distributional analyses were used to examine the joint effects of stimulus quality and word frequency on underlying response time distributions. Consistent with the extant literature, stimulus quality and word frequency produced additive effects in lexical decision, not only in the means but also in the…

  13. Decision-Tree Models of Categorization Response Times, Choice Proportions, and Typicality Judgments

    ERIC Educational Resources Information Center

    Lafond, Daniel; Lacouture, Yves; Cohen, Andrew L.

    2009-01-01

    The authors present 3 decision-tree models of categorization adapted from T. Trabasso, H. Rollins, and E. Shaughnessy (1971) and use them to provide a quantitative account of categorization response times, choice proportions, and typicality judgments at the individual-participant level. In Experiment 1, the decision-tree models were fit to…

  14. 33 CFR 155.4040 - Response times for each salvage and marine firefighting service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and marine firefighting service. 155.4040 Section 155.4040 Navigation and Navigable Waters COAST GUARD... REGULATIONS FOR VESSELS Salvage and Marine Firefighting § 155.4040 Response times for each salvage and marine firefighting service. (a) You must ensure, by contract or other approved means, that your resource...

  15. 33 CFR 155.4040 - Response times for each salvage and marine firefighting service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and marine firefighting service. 155.4040 Section 155.4040 Navigation and Navigable Waters COAST GUARD... REGULATIONS FOR VESSELS Salvage and Marine Firefighting § 155.4040 Response times for each salvage and marine firefighting service. (a) You must ensure, by contract or other approved means, that your resource...

  16. 33 CFR 155.4040 - Response times for each salvage and marine firefighting service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and marine firefighting service. 155.4040 Section 155.4040 Navigation and Navigable Waters COAST GUARD... REGULATIONS FOR VESSELS Salvage and Marine Firefighting § 155.4040 Response times for each salvage and marine firefighting service. (a) You must ensure, by contract or other approved means, that your resource...

  17. 33 CFR 155.4040 - Response times for each salvage and marine firefighting service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and marine firefighting service. 155.4040 Section 155.4040 Navigation and Navigable Waters COAST GUARD... REGULATIONS FOR VESSELS Salvage and Marine Firefighting § 155.4040 Response times for each salvage and marine firefighting service. (a) You must ensure, by contract or other approved means, that your resource...

  18. Semiparametric estimation of treatment effect with time-lagged response in the presence of informative censoring.

    PubMed

    Lu, Xiaomin; Tsiatis, Anastasios A

    2011-10-01

    In many randomized clinical trials, the primary response variable, for example, the survival time, is not observed directly after the patients enroll in the study but rather observed after some period of time (lag time). It is often the case that such a response variable is missing for some patients due to censoring that occurs when the study ends before the patient's response is observed or when the patients drop out of the study. It is often assumed that censoring occurs at random which is referred to as noninformative censoring; however, in many cases such an assumption may not be reasonable. If the missing data are not analyzed properly, the estimator or test for the treatment effect may be biased. In this paper, we use semiparametric theory to derive a class of consistent and asymptotically normal estimators for the treatment effect parameter which are applicable when the response variable is right censored. The baseline auxiliary covariates and post-treatment auxiliary covariates, which may be time-dependent, are also considered in our semiparametric model. These auxiliary covariates are used to derive estimators that both account for informative censoring and are more efficient then the estimators which do not consider the auxiliary covariates. PMID:21706378

  19. 49 CFR 234.103 - Timely response to report of malfunction.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Timely response to report of malfunction. 234.103 Section 234.103 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS...

  20. 49 CFR 234.103 - Timely response to report of malfunction.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Timely response to report of malfunction. 234.103 Section 234.103 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS...

  1. Response-Time Tests of Logical-Rule Models of Categorization

    ERIC Educational Resources Information Center

    Little, Daniel R.; Nosofsky, Robert M.; Denton, Stephen E.

    2011-01-01

    A recent resurgence in logical-rule theories of categorization has motivated the development of a class of models that predict not only choice probabilities but also categorization response times (RTs; Fific, Little, & Nosofsky, 2010). The new models combine mental-architecture and random-walk approaches within an integrated framework and predict…

  2. On the Linear Relation between the Mean and the Standard Deviation of a Response Time Distribution

    ERIC Educational Resources Information Center

    Wagenmakers, Eric-Jan; Brown, Scott

    2007-01-01

    Although it is generally accepted that the spread of a response time (RT) distribution increases with the mean, the precise nature of this relation remains relatively unexplored. The authors show that in several descriptive RT distributions, the standard deviation increases linearly with the mean. Results from a wide range of tasks from different…

  3. Ultrafast Time Response Pressure-Sensitive Paint for Unsteady Shock-Wave Research

    NASA Astrophysics Data System (ADS)

    Numata, Daiju; Asai, Keisuke

    Pressure-Sensitive Paint (PSP) is an optical pressure measurement technique widely used in aerodynamic experiments, and has been applied to unsteady shock-wave phenomena [1, 2]. However, one of the largest problems to apply PSP to high-speed and unsteady phenomena is the response time of PSP.

  4. Assessment of a Rotating Time Sampling Procedure: Implications for Interobserver Agreement and Response Measurement

    ERIC Educational Resources Information Center

    Becraft, Jessica L.; Borrero, John C.; Davis, Barbara J.; Mendres-Smith, Amber E.

    2016-01-01

    The current study was designed to evaluate a rotating momentary time sampling (MTS) data collection system. A rotating MTS system has been used to measure activity preferences of preschoolers but not to collect data on responses that vary in duration and frequency (e.g., talking). We collected data on talking for 10 preschoolers using a 5-s MTS…

  5. Acute Time to Response in the Treatment for Adolescents with Depression Study (TADS)

    ERIC Educational Resources Information Center

    Kratochvil, Christopher; Emslie, Graham; Silva, Susan; McNulty, Steve; Walkup, John; Curry, John; Reinecke, Mark; Vitiello, Benedetto; Rohde, Paul; Feeny, Nora; Casat, Charles; Pathak, Sanjeev; Weller, Elizabeth; May, Diane; Mayes, Taryn; Robins, Michele; March, John

    2006-01-01

    Objective: To examine the time to response for both pharmacotherapy and psychotherapy in the Treatment for Adolescents with Depression Study (TADS). Method: Adolescents (N = 439, ages 12 to 17 years) with major depressive disorder were randomized to fluoxetine (FLX), cognitive-behavioral therapy (CBT), their combination (COMB), or pill placebo…

  6. Cognitive performance and BMI in childhood: Shared genetic influences between reaction time but not response inhibition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this work is to understand whether shared genetic influences can explain the associationbetween obesity and cognitive performance, including slower and more variable reaction times(RTs) and worse response inhibition. RT on a four-choice RT task and the go/no-go task, and commission errors...

  7. Three Essays on Teacher Education Programs and Test-Takers' Response Times on Test Items

    ERIC Educational Resources Information Center

    Qian, Hong

    2013-01-01

    This dissertation includes three essays: one essay focuses on the effect of teacher preparation programs on teacher knowledge while the other two focus on test-takers' response times on test items. Essay One addresses the problem of how opportunities to learn in teacher preparation programs influence future elementary mathematics teachers'…

  8. Setting the Response Time Threshold Parameter to Differentiate Solution Behavior from Rapid-Guessing Behavior

    ERIC Educational Resources Information Center

    Kong, Xiaojing J.; Bhola, Dennison S.; Wise, Steven L.

    2005-01-01

    In this study four methods were compared for setting a response time threshold that differentiates rapid-guessing behavior from solution behavior when examinees are obliged to complete a low-stakes test. The four methods examined were: (1) a fixed threshold for all test items; (2) thresholds based on item surface features such as the amount of…

  9. An Investigation of Relationships Among Question Level, Response Level and Lapse Time

    ERIC Educational Resources Information Center

    Arnold, Daniel S.; And Others

    1973-01-01

    Studied relationships among questioning lapse time'' and the cognitive levels of teachers' questions and youngsters' responses, using Bloom's taxonomy and tape recordings in student teaching. Concluded that teachers' questions above the memory level could serve as a mechanism for promoting youngsters' learning at higher cognitive levels. (CC)

  10. Norms of Filial Responsibility for Aging Parents across Time and Generations

    ERIC Educational Resources Information Center

    Gans, Daphna; Silverstein, Merril

    2006-01-01

    This investigation examined the normative expectation that adult children should be responsible for the care of their aging parents, and how this norm changes over the adult life span, across several decades of historical time, in relation to generational position in families, and between successive generations. Analyses were performed using 4…

  11. Do Visual Processing Deficits Cause Problem on Response Time Task for Dyslexics?

    ERIC Educational Resources Information Center

    Sigmundsson, H.

    2005-01-01

    This study was set out to explore the prediction that dyslexics would be likely to have particular problems compared to control group, on response time task when 'driving' a car simulator. The reason for doing so stems from the fact that there is considerable body of research on visual processing difficulties manifested by dyslexics. The task was…

  12. 5 CFR 2424.25 - Response of the exclusive representative; purpose; time limits; content; severance; service.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... information set forth in paragraph (c) of this section. (e) Service. A copy of the response of the exclusive...; purpose; time limits; content; severance; service. 2424.25 Section 2424.25 Administrative Personnel... SERVICE IMPASSES PANEL FEDERAL LABOR RELATIONS AUTHORITY AND GENERAL COUNSEL OF THE FEDERAL...

  13. 5 CFR 2424.25 - Response of the exclusive representative; purpose; time limits; content; severance; service.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... information set forth in paragraph (c) of this section. (e) Service. A copy of the response of the exclusive...; purpose; time limits; content; severance; service. 2424.25 Section 2424.25 Administrative Personnel... SERVICE IMPASSES PANEL FEDERAL LABOR RELATIONS AUTHORITY AND GENERAL COUNSEL OF THE FEDERAL...

  14. Response-Time Variability Is Related to Parent Ratings of Inattention, Hyperactivity, and Executive Function

    ERIC Educational Resources Information Center

    Gomez-Guerrero, Lorena; Martin, Cristina Dominguez; Mairena, Maria Angeles; Di Martino, Adriana; Wang, Jing; Mendelsohn, Alan L.; Dreyer, Benard P.; Isquith, Peter K.; Gioia, Gerard; Petkova, Eva; Castellanos, F. Xavier

    2011-01-01

    Objective: Individuals with ADHD are often characterized as inconsistent across many contexts. ADHD is also associated with deficits in executive function. We examined the relationships between response time (RT) variability on five brief computer tasks to parents' ratings of ADHD-related features and executive function in a group of children with…

  15. What Are the Shapes of Response Time Distributions in Visual Search?

    ERIC Educational Resources Information Center

    Palmer, Evan M.; Horowitz, Todd S.; Torralba, Antonio; Wolfe, Jeremy M.

    2011-01-01

    Many visual search experiments measure response time (RT) as their primary dependent variable. Analyses typically focus on mean (or median) RT. However, given enough data, the RT distribution can be a rich source of information. For this paper, we collected about 500 trials per cell per observer for both target-present and target-absent displays…

  16. Comparison of response times of a mobile-web EHRs system using PHP and JSP languages.

    PubMed

    De la Torre-Díez, Isabel; Antón-Rodríguez, Míriam; Díaz-Pernas, Francisco Javier; Perozo-Rondón, Freddy José

    2012-12-01

    Performance evaluation is highly important in the Electronic Health Records (EHRs) system implementation. Response time's measurement can be considered as one manner to make that evaluation. In the e-health field, after the creation of EHRs available through different platforms such as Web and/or mobile, a performance evaluation is necessary. The operation of the system in the right way is essential. In this paper, a comparison of the response times for the MEHRmobile system is presented. The first version uses PHP language with a MySQL database and the second one employs JSP with an eXist database. Both versions have got the same functionalities. In addition to the technological aspects, a significant difference is the way the information is stored. The main goal of this paper is choosing the version which offers better response times. We have created a new benchmark to calculate the response times. Better results have been obtained for the PHP version. Nowadays, this version is being used for specialists from Fundación Intras, Spain.

  17. Correction method for averaging slowly time-variant room impulse response measurements.

    PubMed

    Postma, Barteld N J; Katz, Brian F G

    2016-07-01

    Various methods exist for room acoustic measurements. To increase the signal-to-noise-ratio (SNR), averaging of repeated room impulse responses (RIR) can be performed under the assumption of time-invariant systems. Associated with a study of the Paris Notre Dame cathedral, time-variances due to minute temperature changes were observed which confounded results of averaged RIRs, producing significantly shorter reverberation times. A correction method for such time-variance of the acoustic system is proposed, based on time-stretching. Following correction, reverberation times of averaged RIRs were comparable to expected tolerance ranges for measurements, well within one just noticeable difference, while also exhibiting a mid-frequency SNR gain of 8 dB. PMID:27475209

  18. Correction method for averaging slowly time-variant room impulse response measurements.

    PubMed

    Postma, Barteld N J; Katz, Brian F G

    2016-07-01

    Various methods exist for room acoustic measurements. To increase the signal-to-noise-ratio (SNR), averaging of repeated room impulse responses (RIR) can be performed under the assumption of time-invariant systems. Associated with a study of the Paris Notre Dame cathedral, time-variances due to minute temperature changes were observed which confounded results of averaged RIRs, producing significantly shorter reverberation times. A correction method for such time-variance of the acoustic system is proposed, based on time-stretching. Following correction, reverberation times of averaged RIRs were comparable to expected tolerance ranges for measurements, well within one just noticeable difference, while also exhibiting a mid-frequency SNR gain of 8 dB.

  19. The looks of an odour - Visualising neural odour response patterns in real time

    PubMed Central

    2013-01-01

    Background Calcium imaging in insects reveals the neural response to odours, both at the receptor level on the antenna and in the antennal lobe, the first stage of olfactory information processing in the brain. Changes of intracellular calcium concentration in response to odour presentations can be observed by employing calcium-sensitive, fluorescent dyes. The response pattern across all recorded units is characteristic for the odour. Method Previously, extraction of odour response patterns from calcium imaging movies was performed offline, after the experiment. We developed software to extract and to visualise odour response patterns in real time. An adaptive algorithm in combination with an implementation for the graphics processing unit enables fast processing of movie streams. Relying on correlations between pixels in the temporal domain, the calcium imaging movie can be segmented into regions that correspond to the neural units. Results We applied our software to calcium imaging data recorded from the antennal lobe of the honeybee Apis mellifera and from the antenna of the fruit fly Drosophila melanogaster. Evaluation on reference data showed results comparable to those obtained by previous offline methods while computation time was significantly lower. Demonstrating practical applicability, we employed the software in a real-time experiment, performing segmentation of glomeruli - the functional units of the honeybee antennal lobe - and visualisation of glomerular activity patterns. Conclusions Real-time visualisation of odour response patterns expands the experimental repertoire targeted at understanding information processing in the honeybee antennal lobe. In interactive experiments, glomeruli can be selected for manipulation based on their present or past activity, or based on their anatomical position. Apart from supporting neurobiology, the software allows for utilising the insect antenna as a chemosensor, e.g. to detect or to classify odours. PMID

  20. Improving linear accelerator service response with a real- time electronic event reporting system.

    PubMed

    Hoisak, Jeremy D P; Pawlicki, Todd; Kim, Gwe-Ya; Fletcher, Richard; Moore, Kevin L

    2014-09-08

    To track linear accelerator performance issues, an online event recording system was developed in-house for use by therapists and physicists to log the details of technical problems arising on our institution's four linear accelerators. In use since October 2010, the system was designed so that all clinical physicists would receive email notification when an event was logged. Starting in October 2012, we initiated a pilot project in collaboration with our linear accelerator vendor to explore a new model of service and support, in which event notifications were also sent electronically directly to dedicated engineers at the vendor's technical help desk, who then initiated a response to technical issues. Previously, technical issues were reported by telephone to the vendor's call center, which then disseminated information and coordinated a response with the Technical Support help desk and local service engineers. The purpose of this work was to investigate the improvements to clinical operations resulting from this new service model. The new and old service models were quantitatively compared by reviewing event logs and the oncology information system database in the nine months prior to and after initiation of the project. Here, we focus on events that resulted in an inoperative linear accelerator ("down" machine). Machine downtime, vendor response time, treatment cancellations, and event resolution were evaluated and compared over two equivalent time periods. In 389 clinical days, there were 119 machine-down events: 59 events before and 60 after introduction of the new model. In the new model, median time to service response decreased from 45 to 8 min, service engineer dispatch time decreased 44%, downtime per event decreased from 45 to 20 min, and treatment cancellations decreased 68%. The decreased vendor response time and reduced number of on-site visits by a service engineer resulted in decreased downtime and decreased patient treatment cancellations.

  1. Improving linear accelerator service response with a real- time electronic event reporting system.

    PubMed

    Hoisak, Jeremy D P; Pawlicki, Todd; Kim, Gwe-Ya; Fletcher, Richard; Moore, Kevin L

    2014-01-01

    To track linear accelerator performance issues, an online event recording system was developed in-house for use by therapists and physicists to log the details of technical problems arising on our institution's four linear accelerators. In use since October 2010, the system was designed so that all clinical physicists would receive email notification when an event was logged. Starting in October 2012, we initiated a pilot project in collaboration with our linear accelerator vendor to explore a new model of service and support, in which event notifications were also sent electronically directly to dedicated engineers at the vendor's technical help desk, who then initiated a response to technical issues. Previously, technical issues were reported by telephone to the vendor's call center, which then disseminated information and coordinated a response with the Technical Support help desk and local service engineers. The purpose of this work was to investigate the improvements to clinical operations resulting from this new service model. The new and old service models were quantitatively compared by reviewing event logs and the oncology information system database in the nine months prior to and after initiation of the project. Here, we focus on events that resulted in an inoperative linear accelerator ("down" machine). Machine downtime, vendor response time, treatment cancellations, and event resolution were evaluated and compared over two equivalent time periods. In 389 clinical days, there were 119 machine-down events: 59 events before and 60 after introduction of the new model. In the new model, median time to service response decreased from 45 to 8 min, service engineer dispatch time decreased 44%, downtime per event decreased from 45 to 20 min, and treatment cancellations decreased 68%. The decreased vendor response time and reduced number of on-site visits by a service engineer resulted in decreased downtime and decreased patient treatment cancellations. PMID

  2. Mean Transit Time as a Predictor of Groundwater Discharge Response in the Upper Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Solder, J. E.; Heilweil, V. M.; Stolp, B. J.; Susong, D.

    2015-12-01

    The Colorado River and its tributaries support 40 million municipal water users and 5.5 million acres of agriculture in the south western United States (U.S. Bureau of Reclamation, 2012). Recent estimates by Rumsey et al. (2015) suggest that a significant portion (about 50 percent) of surface water flow in the Upper Colorado River Basin (UCRB) is sustained by groundwater discharge to streams. Predicted climate variation (Cook et al., 2015) and increased water demand (U.S. Bureau of Reclamation, 2012) within the UCRB suggest future decreases in groundwater discharge, however transient groundwater responses are not well understood. In this study we calculate groundwater mean transit time (MTT) and transit time distribution (TTD) as predictors of the pattern and timing of groundwater response to hydraulic stress. Samples from nineteen large springs within the UCRB were analyzed for environmental tracers to determine MTT and TTD. The predictive value of the MTT is examined by a statistical analysis of MTT, historical spring discharge records, and the Palmer Hydrological Drought Index. MTTs of the 19 springs range from 10 to 15,000 years with a flow-weighted average of 1,650 years. The composite TTD of the 19 springs suggest that flowpaths representing 45 percent of their combined discharge have transit times greater than 100 years. However, spring discharge records indicate that flow responds to drought on much shorter (0.5 - 6 year) time scales, indicative of a hydraulic pressure response. Springs with shorter MTTs (< 100) generally correlated with larger discharge variations and faster responses to drought indicating MTT can be used for estimating the relative magnitude and timing of groundwater response. Previous study (e.g., Manga, 1999) has shown groundwater responds on shorter time scales than the MTT, but of interest the results presented here indicate that relatively stable and old springs with long MTTs (> 100) also show a hydraulic pressure response. While

  3. Demand response-enabled model predictive HVAC load control in buildings using real-time electricity pricing

    NASA Astrophysics Data System (ADS)

    Avci, Mesut

    A practical cost and energy efficient model predictive control (MPC) strategy is proposed for HVAC load control under dynamic real-time electricity pricing. The MPC strategy is built based on a proposed model that jointly minimizes the total energy consumption and hence, cost of electricity for the user, and the deviation of the inside temperature from the consumer's preference. An algorithm that assigns temperature set-points (reference temperatures) to price ranges based on the consumer's discomfort tolerance index is developed. A practical parameter prediction model is also designed for mapping between the HVAC load and the inside temperature. The prediction model and the produced temperature set-points are integrated as inputs into the MPC controller, which is then used to generate signal actions for the AC unit. To investigate and demonstrate the effectiveness of the proposed approach, a simulation based experimental analysis is presented using real-life pricing data. An actual prototype for the proposed HVAC load control strategy is then built and a series of prototype experiments are conducted similar to the simulation studies. The experiments reveal that the MPC strategy can lead to significant reductions in overall energy consumption and cost savings for the consumer. Results suggest that by providing an efficient response strategy for the consumers, the proposed MPC strategy can enable the utility providers to adopt efficient demand management policies using real-time pricing. Finally, a cost-benefit analysis is performed to display the economic feasibility of implementing such a controller as part of a building energy management system, and the payback period is identified considering cost of prototype build and cost savings to help the adoption of this controller in the building HVAC control industry.

  4. Dynamic response analysis of structure under time-variant interval process model

    NASA Astrophysics Data System (ADS)

    Xia, Baizhan; Qin, Yuan; Yu, Dejie; Jiang, Chao

    2016-10-01

    Due to the aggressiveness of the environmental factor, the variation of the dynamic load, the degeneration of the material property and the wear of the machine surface, parameters related with the structure are distinctly time-variant. Typical model for time-variant uncertainties is the random process model which is constructed on the basis of a large number of samples. In this work, we propose a time-variant interval process model which can be effectively used to deal with time-variant uncertainties with limit information. And then two methods are presented for the dynamic response analysis of the structure under the time-variant interval process model. The first one is the direct Monte Carlo method (DMCM) whose computational burden is relative high. The second one is the Monte Carlo method based on the Chebyshev polynomial expansion (MCM-CPE) whose computational efficiency is high. In MCM-CPE, the dynamic response of the structure is approximated by the Chebyshev polynomials which can be efficiently calculated, and then the variational range of the dynamic response is estimated according to the samples yielded by the Monte Carlo method. To solve the dependency phenomenon of the interval operation, the affine arithmetic is integrated into the Chebyshev polynomial expansion. The computational effectiveness and efficiency of MCM-CPE is verified by two numerical examples, including a spring-mass-damper system and a shell structure.

  5. Response mode does not modulate the space-time congruency effect: evidence for a space-time mapping at a conceptual level.

    PubMed

    Eikmeier, Verena; Hoppe, Dorothée; Ulrich, Rolf

    2015-03-01

    Previous studies reported a space-time congruency effect on response time, supporting the notion that people's thinking about time is grounded in their spatial sensorimotor experience. According to a strong view of metaphoric mapping, the congruency effect should be larger for responses that differ in their spatial features than for responses that lack such differences. In contrast, a weaker version of this account posits that the grounding of time is based on higher-level spatial concepts. In this case, response mode should not modulate the size of the space-time congruency effect. In order to assess these predictions, participants in this study responded to temporal stimuli either manually or vocally. Response mode did not modulate the space-time congruency effect which supports the weaker view of metaphoric mapping suggesting that this effect emerges at a higher cognitive level.

  6. Self-Actualization, Liberalism, and Humanistic Education.

    ERIC Educational Resources Information Center

    Porter, Charles Mack

    1979-01-01

    The relationship between personality factors and political orientation has long been of interest to psychologists. This study tests the hypothesis that there is no significant relationship between self-actualization and liberalism-conservatism. The hypothesis is supported. (Author)

  7. Gauging triple stores with actual biological data

    PubMed Central

    2012-01-01

    Background Semantic Web technologies have been developed to overcome the limitations of the current Web and conventional data integration solutions. The Semantic Web is expected to link all the data present on the Internet instead of linking just documents. One of the foundations of the Semantic Web technologies is the knowledge representation language Resource Description Framework (RDF). Knowledge expressed in RDF is typically stored in so-called triple stores (also known as RDF stores), from which it can be retrieved with SPARQL, a language designed for querying RDF-based models. The Semantic Web technologies should allow federated queries over multiple triple stores. In this paper we compare the efficiency of a set of biologically relevant queries as applied to a number of different triple store implementations. Results Previously we developed a library of queries to guide the use of our knowledge base Cell Cycle Ontology implemented as a triple store. We have now compared the performance of these queries on five non-commercial triple stores: OpenLink Virtuoso (Open-Source Edition), Jena SDB, Jena TDB, SwiftOWLIM and 4Store. We examined three performance aspects: the data uploading time, the query execution time and the scalability. The queries we had chosen addressed diverse ontological or biological questions, and we found that individual store performance was quite query-specific. We identified three groups of queries displaying similar behaviour across the different stores: 1) relatively short response time queries, 2) moderate response time queries and 3) relatively long response time queries. SwiftOWLIM proved to be a winner in the first group, 4Store in the second one and Virtuoso in the third one. Conclusions Our analysis showed that some queries behaved idiosyncratically, in a triple store specific manner, mainly with SwiftOWLIM and 4Store. Virtuoso, as expected, displayed a very balanced performance - its load time and its response time for all the

  8. Improved time response for large area microchannel plate photomultiplier tubes in fusion diagnostics

    SciTech Connect

    Milnes, J. S. Conneely, T. M.; Howorth, J.; Horsfield, C. J.

    2014-11-15

    Fusion diagnostics that utilise high speed scintillators often need to capture a large area of light with a high degree of time accuracy. Microchannel plate (MCP) photomultiplier tubes (PMTs) are recognised as the leading device for capturing fast optical signals. However, when manufactured in their traditional proximity focused construction, the time response performance is reduced as the active area increases. This is due to two main factors: the capacitance of a large anode and the difficulty of obtaining small pore MCPs with a large area. Collaboration between Photek and AWE has produced prototype devices that combine the excellent time response of small area MCP-PMTs with a large active area by replacing the traditional proximity-gap front section with an electro-optically focused photocathode to MCP. We present results from both single and double MCP devices with a 40 mm diameter active area and show simulations for the 100 mm device being built this year.

  9. Inhibition of return: sensitivity and criterion as a function of response time.

    PubMed

    Ivanoff, Jason; Klein, Raymond M

    2006-08-01

    Inhibition of return (IOR) refers to a mechanism that results in a performance disadvantage typically observed when targets are presented at a location once occupied by a cue. Although the time course of the phenomenon--from the cue to the target--has been well studied, the time course of the effect--from target to response--is unknown. In 2 experiments, the effect of IOR upon sensitivity and response criterion under different levels of speed stress was examined. In go/no-go and choice reaction time tasks, IOR had at least 2 distinct effects on information processing. Early in target processing, before sufficient target information has accrued, there is a bias against responding to cued targets. Later, as target information is allowed to accrue, IOR reduces sensitivity to the target's nonspatial feature. Three accounts relating to the early bias effect of IOR and the late effect of IOR on sensitivity are offered. PMID:16846287

  10. Time of day influences the voluntary intake and behavioral response to methamphetamine and food reward.

    PubMed

    Keith, Diana R; Hart, Carl L; Robotham, Margaret; Tariq, Maliha; Le Sauter, Joseph; Silver, Rae

    2013-09-01

    The circadian timing system influences a vast array of behavioral responses. Substantial evidence indicates a role for the circadian system in regulating reward processing. Here we explore time of day effects on drug anticipation, locomotor activity, and voluntary methamphetamine (MA) and food intake in animals with ad libitum food access. We compared responses to drug versus a palatable treat during their normal sleep times in early day (zeitgeber time (ZT) 0400) or late day (ZT 1000). In the first study, using a between-subjects design, mice were given daily 1-h access to either peanut butter (PB-Alone) or to a low or high concentration of MA mixed in PB (MA+PB). In study 2, we repeated the experiment using a within-subjects design in which mice could choose between PB-Alone and MA+PB at either ZT 0400 or 1000. In study 3, the effects of MA-alone were investigated by evaluating anticipatory activity preceding exposure to nebulized MA at ZT 0400 vs. ZT 1000. Time of day effects were observed for both drug and palatable treat, such that in the between groups design, animals showed greater intake, anticipatory activity, and post-ingestional activity in the early day. Furthermore, there were differences among mice in the amount of MA ingested but individuals were self-consistent in their daily intake. The results for the within-subjects experiment also revealed robust individual differences in preference for MA+PB or PB-Alone. Interestingly, time of day effects on intake were observed only for the preferred substance. Anticipatory activity preceding administration of MA by nebulization was also greater at ZT 0400 than ZT 1000. Finally, pharmacokinetic response to MA administered intraperitoneally did not vary as a function of time of administration. The results indicate that time of day is an important variable mediating the voluntary intake and behavioral effects of reinforcers.

  11. Time-variant modelling of heart rate responses to exercise intensity during road cycling.

    PubMed

    Lefever, Joris; Berckmans, Daniel; Aerts, Jean-Marie

    2014-01-01

    The aim of this study was to determine if heart rate responses to training intensity during road cycling could be modelled with compact time-variant mathematical model structures. The model performance was evaluated in terms of model order (complexity), number of inputs and parameter estimation methods used (time-invariant vs. time-variant). Thirteen male cyclists performed two identical cycling tests of 27 km on the road. Uphill sections were introduced to induce dynamic variations in heart rate. The heart rate and training intensity, represented by power output and road inclination, were measured in real-time. Taking only power as system input allowed to explain the variations in heart rate in an accurate way R2 T = 0.86 ± 0.08, since adding the road inclination as an additional input did not significantly improve the modelling performance R2 T = 0.87 ± 0.08, P = 0.32. Furthermore, we demonstrated that models with first-order dynamics accurately describes the heart rate responses to power variations R2 T = 0.86 ± 0.08, but that more complex second-order model structures R2 T = 0.88 ± 0.08 were significantly better than the first-order model structures (P = 0.028). Finally, the heart rate dynamics appeared to be time-variant, since the time-variant model structures R2 T = 0.89 ± 0.07 were significantly better than the time-invariant model structures R2 T = 0.84 ± 0.08, P = 0.0002. So, compact time-variant second-order model structures could be used to model the heart rate response to training intensity as a basis for training optimisation.

  12. Increasing temperature forcing reduces the Greenland Ice Sheet's response time scale

    NASA Astrophysics Data System (ADS)

    Applegate, Patrick J.; Parizek, Byron R.; Nicholas, Robert E.; Alley, Richard B.; Keller, Klaus

    2015-10-01

    Damages from sea level rise, as well as strategies to manage the associated risk, hinge critically on the time scale and eventual magnitude of sea level rise. Satellite observations and paleo-data suggest that the Greenland Ice Sheet (GIS) loses mass in response to increased temperatures, and may thus contribute substantially to sea level rise as anthropogenic climate change progresses. The time scale of GIS mass loss and sea level rise are deeply uncertain, and are often assumed to be constant. However, previous ice sheet modeling studies have shown that the time scale of GIS response likely decreases strongly with increasing temperature anomaly. Here, we map the relationship between temperature anomaly and the time scale of GIS response, by perturbing a calibrated, three-dimensional model of GIS behavior. Additional simulations with a profile, higher-order, ice sheet model yield time scales that are broadly consistent with those obtained using the three-dimensional model, and shed light on the feedbacks in the ice sheet system that cause the time scale shortening. Semi-empirical modeling studies that assume a constant time scale of sea level adjustment, and are calibrated to small preanthropogenic temperature and sea level changes, may underestimate future sea level rise. Our analysis suggests that the benefits of reducing greenhouse gas emissions, in terms of avoided sea level rise from the GIS, may be greatest if emissions reductions begin before large temperature increases have been realized. Reducing anthropogenic climate change may also allow more time for design and deployment of risk management strategies by slowing sea level contributions from the GIS.

  13. Time of day influences the voluntary intake and behavioral response to methamphetamine and food reward.

    PubMed

    Keith, Diana R; Hart, Carl L; Robotham, Margaret; Tariq, Maliha; Le Sauter, Joseph; Silver, Rae

    2013-09-01

    The circadian timing system influences a vast array of behavioral responses. Substantial evidence indicates a role for the circadian system in regulating reward processing. Here we explore time of day effects on drug anticipation, locomotor activity, and voluntary methamphetamine (MA) and food intake in animals with ad libitum food access. We compared responses to drug versus a palatable treat during their normal sleep times in early day (zeitgeber time (ZT) 0400) or late day (ZT 1000). In the first study, using a between-subjects design, mice were given daily 1-h access to either peanut butter (PB-Alone) or to a low or high concentration of MA mixed in PB (MA+PB). In study 2, we repeated the experiment using a within-subjects design in which mice could choose between PB-Alone and MA+PB at either ZT 0400 or 1000. In study 3, the effects of MA-alone were investigated by evaluating anticipatory activity preceding exposure to nebulized MA at ZT 0400 vs. ZT 1000. Time of day effects were observed for both drug and palatable treat, such that in the between groups design, animals showed greater intake, anticipatory activity, and post-ingestional activity in the early day. Furthermore, there were differences among mice in the amount of MA ingested but individuals were self-consistent in their daily intake. The results for the within-subjects experiment also revealed robust individual differences in preference for MA+PB or PB-Alone. Interestingly, time of day effects on intake were observed only for the preferred substance. Anticipatory activity preceding administration of MA by nebulization was also greater at ZT 0400 than ZT 1000. Finally, pharmacokinetic response to MA administered intraperitoneally did not vary as a function of time of administration. The results indicate that time of day is an important variable mediating the voluntary intake and behavioral effects of reinforcers. PMID:23711589

  14. Myosin-II sets the optimal response time scale of chemotactic amoeba

    NASA Astrophysics Data System (ADS)

    Hsu, Hsin-Fang; Westendorf, Christian; Tarantola, Marco; Bodenschatz, Eberhard; Beta, Carsten

    2014-03-01

    The response dynamics of the actin cytoskeleton to external chemical stimuli plays a fundamental role in numerous cellular functions. One of the key players that governs the dynamics of the actin network is the motor protein myosin-II. Here we investigate the role of myosin-II in the response of the actin system to external stimuli. We used a microfluidic device in combination with a photoactivatable chemoattractant to apply stimuli to individual cells with high temporal resolution. We directly compare the actin dynamics in Dictyostelium discodelium wild type (WT) cells to a knockout mutant that is deficient in myosin-II (MNL). Similar to the WT a small population of MNL cells showed self-sustained oscillations even in absence of external stimuli. The actin response of MNL cells to a short pulse of chemoattractant resembles WT during the first 15 sec but is significantly delayed afterward. The amplitude of the dominant peak in the power spectrum from the response time series of MNL cells to periodic stimuli with varying period showed a clear resonance peak at a forcing period of 36 sec, which is significantly delayed as compared to the resonance at 20 sec found for the WT. This shift indicates an important role of myosin-II in setting the response time scale of motile amoeba. Institute of Physics und Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany.

  15. Characterization, Leaching, and Filtration Testing for Tributyl Phosphate (TBP, Group 7) Actual Waste Sample Composites

    SciTech Connect

    Edwards, Matthew K.; Billing, Justin M.; Blanchard, David L.; Buck, Edgar C.; Casella, Amanda J.; Casella, Andrew M.; Crum, J. V.; Daniel, Richard C.; Draper, Kathryn E.; Fiskum, Sandra K.; Jagoda, Lynette K.; Jenson, Evan D.; Kozelisky, Anne E.; MacFarlan, Paul J.; Peterson, Reid A.; Shimskey, Rick W.; Snow, Lanee A.; Swoboda, Robert G.

    2009-03-09

    .A testing program evaluating actual tank waste was developed in response to Task 4 from the M-12 External Flowsheet Review Team (EFRT) issue response plan. The bulk water-insoluble solid wastes that are anticipated to be delivered to the Waste Treatment and Immobilization Plant (WTP) were identified according to type such that the actual waste testing could be targeted to the relevant categories. Eight broad waste groupings were defined. Samples available from the 222S archive were identified and obtained for testing. The actual waste-testing program included homogenizing the samples by group, characterizing the solids and aqueous phases, and performing parametric leaching tests. The tributyl phosphate sludge (TBP, Group 7) is the subject of this report. The Group 7 waste was anticipated to be high in phosphorus as well as aluminum in the form of gibbsite. Both are believed to exist in sufficient quantities in the Group 7 waste to address leaching behavior. Thus, the focus of the Group 7 testing was on the removal of both P and Al. The waste-type definition, archived sample conditions, homogenization activities, characterization (physical, chemical, radioisotope, and crystal habit), and caustic leaching behavior as functions of time, temperature, and hydroxide concentration are discussed in this report. Testing was conducted according to TP-RPP-WTP-467.

  16. Reverberation time measurement using integrated impulse response and sweep sine excitation

    NASA Astrophysics Data System (ADS)

    Nabuco, Marco; Brando, Paulo

    2002-11-01

    As the capacity and speed of digital processing systems becomes much higher, the integrated impulsive response for reverberation time measurements by the indirect method also becomes more feasible and faster. The MLS technique to obtain the impulse response for LTI has been developed during the last several years and it is very well reported by the bibliography. Some frequency analyzers available in the market are capable to generate and process MLS to get the impulse responses very easily. Sometimes, when the room to be tested is very reverberant, sequences of higher order and a certain number of average are necessary to assure acceptable signal-to-noise ratio. The sweep sine technique or the deconvolution method to obtain impulsive responses presents many new advantages, most of them still reported in various technical documents. This paper presents the results of application of this technique to measure the reverberation time in two different reverberation rooms. Comparisons with MLS, ensemble, and reverberation time averages are presented. The sweep sine technique repeatability was verified in a reverberation chamber for a polyurethane foam sample and showed smaller standard deviations when compared with other techniques. (To be presented in Portuguese.)

  17. Modeling confidence judgments, response times, and multiple choices in decision making: recognition memory and motion discrimination.

    PubMed

    Ratcliff, Roger; Starns, Jeffrey J

    2013-07-01

    Confidence in judgments is a fundamental aspect of decision making, and tasks that collect confidence judgments are an instantiation of multiple-choice decision making. We present a model for confidence judgments in recognition memory tasks that uses a multiple-choice diffusion decision process with separate accumulators of evidence for the different confidence choices. The accumulator that first reaches its decision boundary determines which choice is made. Five algorithms for accumulating evidence were compared, and one of them produced proportions of responses for each of the choices and full response time distributions for each choice that closely matched empirical data. With this algorithm, an increase in the evidence in one accumulator is accompanied by a decrease in the others so that the total amount of evidence in the system is constant. Application of the model to the data from an earlier experiment (Ratcliff, McKoon, & Tindall, 1994) uncovered a relationship between the shapes of z-transformed receiver operating characteristics and the behavior of response time distributions. Both are explained in the model by the behavior of the decision boundaries. For generality, we also applied the decision model to a 3-choice motion discrimination task and found it accounted for data better than a competing class of models. The confidence model presents a coherent account of confidence judgments and response time that cannot be explained with currently popular signal detection theory analyses or dual-process models of recognition.

  18. Dynamic response of cracked rotor-bearing system under time-dependent base movements

    NASA Astrophysics Data System (ADS)

    Han, Qinkai; Chu, Fulei

    2013-12-01

    Dynamic response of cracked rotor-bearing system under time-dependent base movements is studied in this paper. Three base angular motions, including the rolling, pitching and yawing motions, are assumed to be sinusoidal perturbations superimposed upon constant terms. Both the open and breathing transverse cracks are considered in the analysis. The finite element model is established for the base excited rotor-bearing system with open or breathing cracks. Considering the time-varying base movements and transverse cracks, the second-order differential equations of the system will not only have time-periodic gyroscopic and stiffness coefficients, but also the multi-frequency external excitations. An improved harmonic balance method is introduced to obtain the steady-state response of the system under both base and unbalance excitations. The response spectra, orbits of shaft center and frequency response characteristics, are analyzed accordingly. The effects of various base angular motions, frequency and amplitude of base excitations, and crack depths on the system dynamic behaviors are considered in the discussions.

  19. Effect of heat exposure on thermoregulation and hockey-specific response time in field hockey goalkeepers.

    PubMed

    Malan, Marcelle; Dawson, Brian; Goodman, Carmel; Peeling, Peter

    2010-05-01

    This study examined the thermoregulatory responses in field hockey goalkeepers during games (Part A), and assessed the effect of heat stress on hockey-specific response time (Part B). In Part A, core temperature (T(c)), skin temperature (T(sk)), body mass, fluid consumption and heart rate (HR) responses of six goalkeepers during two premier level club games in the Western Australian (winter) hockey season were recorded. Part B assessed the same measures, plus a response time test on four goalkeepers playing a simulated game inside a climate chamber in cool (COOL: 20 degrees C, 40% RH) and hot (HOT: 35 degrees C, 40% RH) conditions. In Part A, the mean (+/-SD) T(c) and T(sk) measured in games was 38.49+/-0.20 degrees C and 34.99+/-0.99 degrees C, with increases from baseline of 1.34+/-0.19 degrees C and 1.08+/-0.30 degrees C, respectively. Most of the increase in T(c) resulted from the pre-game warm-up. In Part B, T(c) and T(sk) only increased significantly (p<0.05) from baseline in the HOT condition (0.62+/-0.18 degrees C and 1.61+/-0.82 degrees C, respectively). Response time was significantly slower (0.87+/-0.14s, p<0.01) after heat exposure, compared to COOL (0.75+/-0.15s), but the number of correct responses was not affected. For optimal performance, careful attention should be given to strategies to limit T(c) increases in field hockey goalkeepers during matches.

  20. Response-coefficient method for heat-conduction transients with time-dependent inputs

    NASA Technical Reports Server (NTRS)

    Ceylan, Tamer

    1993-01-01

    A theoretical overview of the response coefficient method for heat conduction transients with time-dependent input forcing functions is presented with a number of illustrative applications. The method may be the most convenient and economical if the same problem is to be solved many times with different input-time histories or if the solution time is relatively long. The method is applicable to a wide variety of problems, including irregular geometries, position-dependent boundary conditions, position-dependent physical properties, and nonperiodic irregular input histories. Nonuniform internal energy generation rates within the structure can also be handled by the method. The area of interest is long-time solutions, in which initial condition is unimportant, and not the early transient period. The method can be applied to one dimensional problems in cartesian, cylindrical, and spherical coordinates as well as to two dimensional problems in cartesian and cylindrical coordinates.

  1. Resolving high-speed colloidal dynamics beyond detector response time via two pulse speckle contrast correlation.

    PubMed

    Lee, Sooheyong; Jo, Wonhyuk; Wi, Haeng Sub; Gutt, C; Lee, Geun Woo

    2014-09-01

    We report an alternate light scattering approach to measure intermediate scattering function and structures of colloidal suspension by using two-pulse speckle contrast correlation analysis. By systematically controlling time-delays between two laser pulses incident on the sample, we are able to monitor transient evolution of coherent diffraction pattern, from which particle dynamics at different length and time scales are obtained simultaneously. Our result demonstrates the feasibility of utilizing a megapixel detector to achieve sufficient data statistics in a short amount of time while enabling microsecond time-resolution. Ultimately, this method provides means to measure high-speed dynamics well beyond the time response limit of a large area two-dimensional (2D) detector.

  2. Modelling residence-time response to freshwater input in Apalachicola Bay, Florida, USA

    NASA Astrophysics Data System (ADS)

    Huang, Wenrui; Spaulding, M.

    2002-10-01

    Residence time of an estuary can be used to estimate the rate of removal of freshwater and pollutants from river inflow. In this study, a calibrated three-dimensional hydrodynamic model was used to determine residence time in response to the change of freshwater input in Apalachicola Bay. The bay is about 40 km long and 7 km wide, with an average 3 m water depth. Through hydrodynamic model simulations, the spatial and temporal salinity and the total freshwater volume in the bay were calculated. Then the freshwater fraction method was used to estimate the residence time. Results indicate that the residence time in Apalachicola Bay typically ranges between 3 and 10 days for the daily freshwater input ranging from 177 m3/s to 4561 m3/s. Regression analysis of model results shows that an exponential regression equation can be used to correlate the estuarine residence time to changes of freshwater input.

  3. Wide dynamic range neutron flux monitor having fast time response for the Large Helical Device.

    PubMed

    Isobe, M; Ogawa, K; Miyake, H; Hayashi, H; Kobuchi, T; Nakano, Y; Watanabe, K; Uritani, A; Misawa, T; Nishitani, T; Tomitaka, M; Kumagai, T; Mashiyama, Y; Ito, D; Kono, S; Yamauchi, M; Takeiri, Y

    2014-11-01

    A fast time response, wide dynamic range neutron flux monitor has been developed toward the LHD deuterium operation by using leading-edge signal processing technologies providing maximum counting rate up to ∼5 × 10(9) counts/s. Because a maximum total neutron emission rate over 1 × 10(16) n/s is predicted in neutral beam-heated LHD plasmas, fast response and wide dynamic range capabilities of the system are essential. Preliminary tests have demonstrated successful performance as a wide dynamic range monitor along the design.

  4. An analysis of thermal response factors and how to reduce their computational time requirement

    NASA Technical Reports Server (NTRS)

    Wiese, M. R.

    1982-01-01

    Te RESFAC2 version of the Thermal Response Factor Program (RESFAC) is the result of numerous modifications and additions to the original RESFAC. These modifications and additions have significantly reduced the program's computational time requirement. As a result of this work, the program is more efficient and its code is both readable and understandable. This report describes what a thermal response factor is; analyzes the original matrix algebra calculations and root finding techniques; presents a new root finding technique and streamlined matrix algebra; supplies ten validation cases and their results.

  5. Effect of bedrest and positive radial acceleration upon peripheral visual response time.

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1972-01-01

    Attempt to determine if peripheral visual response time (RT) could be used as a reliable advanced predictor of +G sub z-related blackout or grayout. The relatively high luminance of the peripheral stimuli used in the experiments may account for the finding that peripheral RT was not sensitive to impending blackout or grayout. The relatively consistent mean RTs within subjects across test days in bed is probably due to the relatively constant response characteristics of the retina and to the high repeatability of the stimuli.

  6. Wide dynamic range neutron flux monitor having fast time response for the Large Helical Device

    SciTech Connect

    Isobe, M. Takeiri, Y.; Ogawa, K.; Miyake, H.; Hayashi, H.; Kobuchi, T.; Nakano, Y.; Watanabe, K.; Uritani, A.; Misawa, T.; Nishitani, T.; Tomitaka, M.; Kumagai, T.; Mashiyama, Y.; Ito, D.; Kono, S.; Yamauchi, M.

    2014-11-15

    A fast time response, wide dynamic range neutron flux monitor has been developed toward the LHD deuterium operation by using leading-edge signal processing technologies providing maximum counting rate up to ∼5 × 10{sup 9} counts/s. Because a maximum total neutron emission rate over 1 × 10{sup 16} n/s is predicted in neutral beam-heated LHD plasmas, fast response and wide dynamic range capabilities of the system are essential. Preliminary tests have demonstrated successful performance as a wide dynamic range monitor along the design.

  7. Wide dynamic range neutron flux monitor having fast time response for the Large Helical Devicea)

    NASA Astrophysics Data System (ADS)

    Isobe, M.; Ogawa, K.; Miyake, H.; Hayashi, H.; Kobuchi, T.; Nakano, Y.; Watanabe, K.; Uritani, A.; Misawa, T.; Nishitani, T.; Tomitaka, M.; Kumagai, T.; Mashiyama, Y.; Ito, D.; Kono, S.; Yamauchi, M.; Takeiri, Y.

    2014-11-01

    A fast time response, wide dynamic range neutron flux monitor has been developed toward the LHD deuterium operation by using leading-edge signal processing technologies providing maximum counting rate up to ˜5 × 109 counts/s. Because a maximum total neutron emission rate over 1 × 1016 n/s is predicted in neutral beam-heated LHD plasmas, fast response and wide dynamic range capabilities of the system are essential. Preliminary tests have demonstrated successful performance as a wide dynamic range monitor along the design.

  8. Equilibrium and Response Properties of the Integrate-and-Fire Neuron in Discrete Time

    PubMed Central

    Helias, Moritz; Deger, Moritz; Diesmann, Markus; Rotter, Stefan

    2009-01-01

    The integrate-and-fire neuron with exponential postsynaptic potentials is a frequently employed model to study neural networks. Simulations in discrete time still have highest performance at moderate numerical errors, which makes them first choice for long-term simulations of plastic networks. Here we extend the population density approach to investigate how the equilibrium and response properties of the leaky integrate-and-fire neuron are affected by time discretization. We present a novel analytical treatment of the boundary condition at threshold, taking both discretization of time and finite synaptic weights into account. We uncover an increased membrane potential density just below threshold as the decisive property that explains the deviations found between simulations and the classical diffusion approximation. Temporal discretization and finite synaptic weights both contribute to this effect. Our treatment improves the standard formula to calculate the neuron's equilibrium firing rate. Direct solution of the Markov process describing the evolution of the membrane potential density confirms our analysis and yields a method to calculate the firing rate exactly. Knowing the shape of the membrane potential distribution near threshold enables us to devise the transient response properties of the neuron model to synaptic input. We find a pronounced non-linear fast response component that has not been described by the prevailing continuous time theory for Gaussian white noise input. PMID:20130755

  9. Can response time be trained with bilateral limb training in children with Down syndrome?

    PubMed Central

    Rao, Pratiksha Tilak; Solomon, John M.

    2015-01-01

    Aims: Response time (RT), that is, the time taken to respond is known to be delayed in children with Down syndrome (DS). We performed a pilot study to evaluate whether bilateral limb training can be used to train RT, in children with DS. Settings and Design: 10 children with DS (5 males) were recruited from a special school in a suburban region using convenience sampling. Subjects and Methods: Response time was measured using an indigenously developed RT Analyzer, before and after intervention, from right and left hand. Structured bilateral limb training was given for a period of 4 weeks, using low-cost, locally available materials, in community settings. Statistical Analysis Used: The Wilcoxon signed ranks test was used for statistical analysis. Results: Significant improvements in RT following 4 weeks of intervention were seen in the left hand (P = 0.006) but not in the right hand (P = 0.104). Conclusions: Response time can be trained in children with DS using 4 weeks of bilateral limb training activities using low-cost, locally available materials. PMID:26167016

  10. The Effects of Time on Task in Response Selection--An ERP Study of Mental Fatigue.

    PubMed

    Möckel, Tina; Beste, Christian; Wascher, Edmund

    2015-01-01

    Long lasting involvement in a cognitive task leads to mental fatigue. Substantial efforts have been undertaken to understand this phenomenon. However, it has been demonstrated that some changes with time on task are not only related to mental fatigue. The present study intends to clarify these effects of time on task unrelated to mental fatigue on response selection processes at the behavioural and electrophysiological level (using event-related potentials, ERPs). Participants had to perform a Simon task for more than 3 hours and rated their experienced mental fatigue and motivation to continue with the task at several time points during the experiment. The results show that at the beginning of the experiment some unspecific modulations of training and adaptation are evident. With time on task participants' ability to resolve response conflict appears to become impaired. The results reveal that time on task effects cannot be completely explained by mental fatigue. Instead, it seems that an interplay of adaptation at the beginning and motivational effects in the course of a task modulate performance and neurophysiological parameters. In future studies it will be important to account for the relative contribution of adaptation and motivation parameters when time on task effects are investigated.

  11. The Effects of Time on Task in Response Selection - An ERP Study of Mental Fatigue

    PubMed Central

    Möckel, Tina; Beste, Christian; Wascher, Edmund

    2015-01-01

    Long lasting involvement in a cognitive task leads to mental fatigue. Substantial efforts have been undertaken to understand this phenomenon. However, it has been demonstrated that some changes with time on task are not only related to mental fatigue. The present study intends to clarify these effects of time on task unrelated to mental fatigue on response selection processes at the behavioural and electrophysiological level (using event-related potentials, ERPs). Participants had to perform a Simon task for more than 3 hours and rated their experienced mental fatigue and motivation to continue with the task at several time points during the experiment. The results show that at the beginning of the experiment some unspecific modulations of training and adaptation are evident. With time on task participants’ ability to resolve response conflict appears to become impaired. The results reveal that time on task effects cannot be completely explained by mental fatigue. Instead, it seems that an interplay of adaptation at the beginning and motivational effects in the course of a task modulate performance and neurophysiological parameters. In future studies it will be important to account for the relative contribution of adaptation and motivation parameters when time on task effects are investigated. PMID:26054837

  12. Response regime studies on standard detectors for decay time determination in phosphor thermometry

    NASA Astrophysics Data System (ADS)

    Knappe, C.; Abou Nada, F.; Lindén, J.; Richter, M.; Aldén, M.

    2013-09-01

    This work compares the extent of linear response regimes from standard time-resolving optical detectors for phosphor thermometry. Different types of Photomultipliers (ordinary and time-gated) as well as an Avalanche Photodiode are tested and compared using the phosphorescent time decay of CdWO4 that ranges from 10 μs down to a few ns within a temperature span of 290 to 580 K. Effects originating from incipient detector saturation, far from obvious to the operator's eye, are revealed as a change in evaluated phosphorescence decay time. Since the decay time of thermographic phosphors itself is used for temperature determination - systematic temperature errors up to several tens of Kelvins may be introduced by such detector saturation. A detector mapping procedure is suggested in order to identify linear response regions where the decay-to-temperature evaluation can be performed unbiased. Generation of such a library is highly recommended prior to any quantitative measurement attempt. Using this detector library, even signals collected in the partly saturated regime can be corrected to their unbiased value extending the usable detector operating range significantly. Further, the use of an external current-to-voltage amplifier proved useful for most applications in time-based phosphor thermometry helping to limit saturation effects whilst maintaining a reasonable bandwidth and signal outputs.

  13. Acute Orthotic Intervention Does Not Affect Muscular Response Times and Activation Patterns at the Knee

    PubMed Central

    Rose, Holly M.; Shultz, Sandra J.; Arnold, Brent L.; Gansneder, Bruce M.; Perrin, David H.

    2002-01-01

    Objective: To evaluate the short-term effect of a semirigid foot orthotic device on response times and activation patterns of knee musculature in individuals with hyperpronation after a lower extremity perturbation in a single-leg, weight-bearing stance. Design and Setting: We used a lower extremity perturbation device designed to produce a forward and either internal or external rotation of the trunk and femur on the weight-bearing tibia to evoke a reflex response. Subjects were tested both with and without orthotic devices. Subjects: Seventeen (13 male, 4 female) volunteers (age, 20.6 ± 1.8 years; height, 181.0 ± 8.1 cm; weight, 87.4 ± 19.5 kg; navicular drop, 12.1 ± 1.8 mm) with a navicular drop greater than 10 mm volunteered for this study. Measurements: Long latency reflex times were recorded via surface electromyography for the medial and lateral hamstrings, gastrocnemius, and quadriceps muscles. Results: A dependent-sample t test revealed a significant decrease in navicular drop with orthotic intervention (P < .0001). With that confirmed, separate repeated-measures analyses of variance with 2 within factors (orthotic condition and muscle) revealed no significant difference in muscle response time between orthotic and nonorthotic conditions for either internal or external rotation perturbation. Although we found a main effect for muscle for both internal (P < .0001) and external (P < .0001) rotation, indicating a preferred muscle activation order, this activation order did not differ between orthotic and nonorthotic conditions (internal rotation P = .674, external rotation P = .829). Conclusions: Our findings suggest that a short-term application of a semirigid orthotic device does not alter muscle response times or activation patterns of the muscles that stabilize the knee. Further research is needed to determine whether changes in activation patterns may occur over time since mechanical adaptations occur with long-term wear. PMID:12937425

  14. Time-Lag in Responses of Birds to Atlantic Forest Fragmentation: Restoration Opportunity and Urgency.

    PubMed

    Uezu, Alexandre; Metzger, Jean Paul

    2016-01-01

    There are few opportunities to evaluate the relative importance of landscape structure and dynamics upon biodiversity, especially in highly fragmented tropical landscapes. Conservation strategies and species risk evaluations often rely exclusively on current aspects of landscape structure, although such limited assumptions are known to be misleading when time-lag responses occur. By relating bird functional-group richness to forest patch size and isolation in ten-year intervals (1956, 1965, 1978, 1984, 1993 and 2003), we revealed that birds with different sensitivity to fragmentation display contrasting responses to landscape dynamics in the Brazilian Atlantic Forest. For non-sensitive groups, there was no time-lag in response: the recent degree of isolation best explains their variation in richness, which likely relates to these species' flexibility to adapt to changes in landscape structure. However, for sensitive bird groups, the 1978 patch area was the best explanatory variable, providing evidence for a 25-year time-lag in response to habitat reduction. Time-lag was more likely in landscapes that encompass large patches, which can support temporarily the presence of some sensitive species, even when habitat cover is relatively low. These landscapes potentially support the most threatened populations and should be priorities for restoration efforts to avoid further species loss. Although time-lags provide an opportunity to counteract the negative consequences of fragmentation, it also reinforces the urgency of restoration actions. Fragmented landscapes will be depleted of biodiversity if landscape structure is only maintained, and not improved. The urgency of restoration action may be even higher in landscapes where habitat loss and fragmentation history is older and where no large fragment remained to act temporarily as a refuge.

  15. [Influence of prehospital response times in the survival of trauma patients in Navarre].

    PubMed

    Ali Ali, B; Fortún Moral, M; Belzunegui Otano, T; Teijeira Álvarez, R; Reyero Díez, D; Cabodevilla Górriz, A

    2015-01-01

    The relation between response times and mortality of polytrauma patients in the so-called "golden hour" continues to be a subject of debate. The purpose of this study is to determine the variables related to mortality in these patients and the influence of response times of the Emergency Medical Services in this mortality. To this end, the data in the "Major Trauma of Navarre" Register (retrospective cohort of polytrauma patients attended to by the Navarre Health Service) were analyzed for the four year period between 2010 and 2013. Of the 217 trauma cases available for the analysis, 42 (19%) died. No significant association was found in the multi-variate analysis between the different response times and mortality: arrival at the scene (odds ratio (OR) 1.0; 95% confidence interval (CI) from 0.99 to 1.01), in the scenario (OR 1.00; 95% CI from 0.98 to 1.02) and total time (OR 1.00; 95% CI from 0.99 to 1.01). The variables that influenced mortality are patient age and severity of injuries measured by the prehospital Triage-Revised Trauma Score (T-RTS) and the New Injury Severity Score (NISS). The mortality of polytrauma patients attended to by the emergency system in our region is influenced by age and by the intensity of the aggression suffered, determined by the prehospital T-RTS and by the NISS. The response times of the hospital do not have a significant influence. PMID:26486533

  16. Time-Lag in Responses of Birds to Atlantic Forest Fragmentation: Restoration Opportunity and Urgency

    PubMed Central

    Uezu, Alexandre; Metzger, Jean Paul

    2016-01-01

    There are few opportunities to evaluate the relative importance of landscape structure and dynamics upon biodiversity, especially in highly fragmented tropical landscapes. Conservation strategies and species risk evaluations often rely exclusively on current aspects of landscape structure, although such limited assumptions are known to be misleading when time-lag responses occur. By relating bird functional-group richness to forest patch size and isolation in ten-year intervals (1956, 1965, 1978, 1984, 1993 and 2003), we revealed that birds with different sensitivity to fragmentation display contrasting responses to landscape dynamics in the Brazilian Atlantic Forest. For non-sensitive groups, there was no time-lag in response: the recent degree of isolation best explains their variation in richness, which likely relates to these species’ flexibility to adapt to changes in landscape structure. However, for sensitive bird groups, the 1978 patch area was the best explanatory variable, providing evidence for a 25-year time-lag in response to habitat reduction. Time-lag was more likely in landscapes that encompass large patches, which can support temporarily the presence of some sensitive species, even when habitat cover is relatively low. These landscapes potentially support the most threatened populations and should be priorities for restoration efforts to avoid further species loss. Although time-lags provide an opportunity to counteract the negative consequences of fragmentation, it also reinforces the urgency of restoration actions. Fragmented landscapes will be depleted of biodiversity if landscape structure is only maintained, and not improved. The urgency of restoration action may be even higher in landscapes where habitat loss and fragmentation history is older and where no large fragment remained to act temporarily as a refuge. PMID:26820548

  17. Time-frequency analysis of railway bridge response in forced vibration

    NASA Astrophysics Data System (ADS)

    Cantero, Daniel; Ülker-Kaustell, Mahir; Karoumi, Raid

    2016-08-01

    This paper suggests the use of the Continuous Wavelet Transform in combination with the Modified Littlewood-Paley basis to analyse bridge responses exited by traversing trains. The analysis provides an energy distribution map in the time-frequency domain that offers a better resolution compared to previous published studies. This is demonstrated with recorded responses of the Skidträsk Bridge, a 36 m long composite bridge located in Sweden. It is shown to be particularly useful to understand the evolution of the energy content during a vehicle crossing event. With this information it is possible to distinguish the effect of several of the governing factors involved in the dynamic response including vehicle's speed and axle configuration as well as non-linear behaviour of the structure.

  18. Time domain simulation of nonlinear response of a coupled TLP system in random seas

    SciTech Connect

    Kim, C.H.; Kim, M.H.; Liu, Y.H.; Zhao, C.T.

    1994-12-31

    This paper presents a result of an analysis of the nonlinear interaction and response of the coupled ISSC-TLP System to the random seas in the time domain. The environmental load also includes the effect of the concurrent steady winds and currents. The first- and second-order wave-exciting forces are calculated using a robust higher-order boundary element method (HOBEM), while the nonlinear tendon dynamic analysis is performed using the three-dimensional hybrid element method with the upgated Lagrangian formulation. The Morison equation is employed for the wave and current load on slender structures. The analysis is focused on the nonlinear responses due to the nonlinear environmental load and nonlinear interaction between the platform and tendons that includes the offset, setdown, large coupled surge-heave motion in the low frequency and resonant heave/pitch responses with the springing loads in the high frequency.

  19. Breathing for answering: the time course of response planning in conversation.

    PubMed

    Torreira, Francisco; Bögels, Sara; Levinson, Stephen C

    2015-01-01

    We investigate the timing of pre-answer inbreaths in order to shed light on the time course of response planning and execution in conversational turn-taking. Using acoustic and inductive plethysmography recordings of seven dyadic conversations in Dutch, we show that pre-answer inbreaths in conversation typically begin briefly after the end of questions. We also show that the presence of a pre-answer inbreath usually co-occurs with substantially delayed answers, with a modal latency of 576 vs. 100 ms for answers not preceded by an inbreath. Based on previously reported minimal latencies for internal intercostal activation and the production of speech sounds, we propose that vocal responses, either in the form of a pre-utterance inbreath or of speech proper when an inbreath is not produced, are typically launched in reaction to information present in the last portion of the interlocutor's turn. We also show that short responses are usually made on residual breath, while longer responses are more often preceded by an inbreath. This relation of inbreaths to answer length suggests that by the time an inbreath is launched, typically during the last few hundred milliseconds of the question, the length of the answer is often prepared to some extent. Together, our findings are consistent with a two-stage model of response planning in conversational turn-taking: early planning of content often carried out in overlap with the incoming turn, and late launching of articulation based on the identification of turn-final cues. PMID:25814976

  20. Response of vegetation to drought time-scales across global land biomes

    NASA Astrophysics Data System (ADS)

    Vicente-Serrano, Sergio M.; Gouveia, Célia; Julio Camarero, Jesús; Beguería, Santiago; Trigo, Ricardo; López-Moreno, Juan I.; Azorín-Molina, César; Pasho, Edmond; Lorenzo-Lacruz, Jorge; Revuelto, Jesús; Morán-Tejeda, Enrique; Sanchez-Lorenzo, Arturo

    2013-01-01

    We evaluated the response of the Earth land biomes to drought by correlating a drought index with three global indicators of vegetation activity and growth: vegetation indices from satellite imagery, tree-ring growth series, and Aboveground Net Primary Production (ANPP) records. Arid and humid biomes are both affected by drought, and we suggest that the persistence of the water deficit (i.e., the drought time-scale) could be playing a key role in determining the sensitivity of land biomes to drought. We found that arid biomes respond to drought at short time-scales; that is, there is a rapid vegetation reaction as soon as water deficits below normal conditions occur. This may be due to the fact that plant species of arid regions have mechanisms allowing them to rapidly adapt to changing water availability. Humid biomes also respond to drought at short time-scales, but in this case the physiological mechanisms likely differ from those operating in arid biomes, as plants usually have a poor adaptability to water shortage. On the contrary, semiarid and subhumid biomes respond to drought at long time-scales, probably because plants are able to withstand water deficits, but they lack the rapid response of arid biomes to drought. These results are consistent among three vegetation parameters analyzed and across different land biomes, showing that the response of vegetation to drought depends on characteristic drought time-scales for each biome. Understanding the dominant time-scales at which drought most influences vegetation might help assessing the resistance and resilience of vegetation and improving our knowledge of vegetation vulnerability to climate change.

  1. Response of vegetation to drought time-scales across global land biomes

    PubMed Central

    Vicente-Serrano, Sergio M.; Gouveia, Célia; Camarero, Jesús Julio; Beguería, Santiago; Trigo, Ricardo; López-Moreno, Juan I.; Azorín-Molina, César; Pasho, Edmond; Lorenzo-Lacruz, Jorge; Revuelto, Jesús; Morán-Tejeda, Enrique; Sanchez-Lorenzo, Arturo

    2013-01-01

    We evaluated the response of the Earth land biomes to drought by correlating a drought index with three global indicators of vegetation activity and growth: vegetation indices from satellite imagery, tree-ring growth series, and Aboveground Net Primary Production (ANPP) records. Arid and humid biomes are both affected by drought, and we suggest that the persistence of the water deficit (i.e., the drought time-scale) could be playing a key role in determining the sensitivity of land biomes to drought. We found that arid biomes respond to drought at short time-scales; that is, there is a rapid vegetation reaction as soon as water deficits below normal conditions occur. This may be due to the fact that plant species of arid regions have mechanisms allowing them to rapidly adapt to changing water availability. Humid biomes also respond to drought at short time-scales, but in this case the physiological mechanisms likely differ from those operating in arid biomes, as plants usually have a poor adaptability to water shortage. On the contrary, semiarid and subhumid biomes respond to drought at long time-scales, probably because plants are able to withstand water deficits, but they lack the rapid response of arid biomes to drought. These results are consistent among three vegetation parameters analyzed and across different land biomes, showing that the response of vegetation to drought depends on characteristic drought time-scales for each biome. Understanding the dominant time-scales at which drought most influences vegetation might help assessing the resistance and resilience of vegetation and improving our knowledge of vegetation vulnerability to climate change. PMID:23248309

  2. Response of vegetation to drought time-scales across global land biomes.

    PubMed

    Vicente-Serrano, Sergio M; Gouveia, Célia; Camarero, Jesús Julio; Beguería, Santiago; Trigo, Ricardo; López-Moreno, Juan I; Azorín-Molina, César; Pasho, Edmond; Lorenzo-Lacruz, Jorge; Revuelto, Jesús; Morán-Tejeda, Enrique; Sanchez-Lorenzo, Arturo

    2013-01-01

    We evaluated the response of the Earth land biomes to drought by correlating a drought index with three global indicators of vegetation activity and growth: vegetation indices from satellite imagery, tree-ring growth series, and Aboveground Net Primary Production (ANPP) records. Arid and humid biomes are both affected by drought, and we suggest that the persistence of the water deficit (i.e., the drought time-scale) could be playing a key role in determining the sensitivity of land biomes to drought. We found that arid biomes respond to drought at short time-scales; that is, there is a rapid vegetation reaction as soon as water deficits below normal conditions occur. This may be due to the fact that plant species of arid regions have mechanisms allowing them to rapidly adapt to changing water availability. Humid biomes also respond to drought at short time-scales, but in this case the physiological mechanisms likely differ from those operating in arid biomes, as plants usually have a poor adaptability to water shortage. On the contrary, semiarid and subhumid biomes respond to drought at long time-scales, probably because plants are able to withstand water deficits, but they lack the rapid response of arid biomes to drought. These results are consistent among three vegetation parameters analyzed and across different land biomes, showing that the response of vegetation to drought depends on characteristic drought time-scales for each biome. Understanding the dominant time-scales at which drought most influences vegetation might help assessing the resistance and resilience of vegetation and improving our knowledge of vegetation vulnerability to climate change.

  3. Time relationship between ambient temperature change and antigen stimulation on immune responses of mice

    NASA Astrophysics Data System (ADS)

    Hayashi, O.; Kikuchi, M.

    1989-03-01

    We investigated the time relationship between ambient temperature change and antigen stimulation on immune responses to sheep red blood cells (SRBC) and polyvinylpyrrolidone (PVP) in mice. In the case of a shift from comfortable (25°C) to cold (8°C) temperatures, suppression in the number of splenic plaque-forming cells (PFC) took place mainly when the shift was done between 1 day before and 2 to 4 days after immunization. The suppression of the PVP response lasted for up to a maximum of 6 days when mice were transferred 1 day before immunization. In the case of a temperature shift from 25° to 36.5°C, the suppressive effect was found when the temperature shift was done between 4 days before and 2 days after immunization. The effect lasted longer than that of the temperature shift to cold, i.e., at least 9 days after the temperature shift. Blood corticosterone levels after the temperature shifts corresponded to changes in the immune responses: elevation of the blood corticosterone levels was observed for only the first 3 days after a temperature shift to 8°C but for 10 days after a temperature shift to 36.5°C during the period time of the experiment. These result suggested that blood corticosterone level contributes to the duration of the effects of temperature shifts on immune responses of mice. Furthermore, it appeared that the early stage of the immune response is more susceptible to temperature shifts than the later stage. To explain these results, the terms “effective period” in the course of physiological adaptation to changed ambient temperature and “susceptible period” in the course of the immune response, were proposed.

  4. Phase Response Synchronization in Neuronal Population with Time-Varying Coupling Strength

    PubMed Central

    Jiao, Xianfa; Zhao, Wanyu; Cao, Jinde

    2015-01-01

    We present the dynamic model of global coupled neuronal population subject to external stimulus by the use of phase sensitivity function. We investigate the effect of time-varying coupling strength on the synchronized phase response of neural population subjected to external harmonic stimulus. For a time-periodic coupling strength, we found that the stimulus with increasing intensity or frequency can reinforce the phase response synchronization in neuronal population of the weakly coupled neural oscillators, and the neuronal population with stronger coupling strength has good adaptability to stimulus. When we consider the dynamics of coupling strength, we found that a strong stimulus can quickly cause the synchronization in the neuronal population, the degree of synchronization grows with the increasing stimulus intensity, and the period of synchronized oscillation induced by external stimulation is related to stimulus frequency. PMID:26640514

  5. Ultralong time response of magnetic fluid based on fiber-optic evanescent field.

    PubMed

    Du, Bobo; Yang, Dexing; Bai, Yang; Yuan, Yuan; Xu, Jian; Jiang, Yajun; Wang, Meirong

    2016-07-20

    The ultralong time (a few hours) response properties of magnetic fluid using etched optical fiber are visualized and investigated experimentally. The operating structure is made by injecting magnetic fluid into a capillary tube that contains etched single-mode fiber. An interesting extreme asymmetry is observed, in which the transmitted light intensity after the etched optical fiber cannot reach the final steady value when the external magnetic field is turned on (referred to as the falling process), while it can reach the stable state quickly once the magnetic field is turned off (referred to as the rising process). The relationship between the response times/loss rates of the transmitted light and the strength of the applied magnetic field is obtained. The physical mechanisms of two different processes are discussed qualitatively. PMID:27463909

  6. Response Time Measurements of the NIF DANTE XRD-31 X-Ray Diodes (Pre-print)

    SciTech Connect

    Don Pellinen and Michael Griffin

    2009-01-23

    The XRD-31 is a fast, windowless X-ray vacuum photodiode developed by EG&G. It is currently the primary fast X-ray detector used to diagnose the X-rays on NIF and OMEGA on the multichannel DANTE spectrometer. The XRD-31 has a dynamic range of less than 1e-12 amps to more than 10 amps. A technique is described to measure the impulse response of the diodes to a 150 fs pulse of 200 nm laser light and a method to calculate the “risetime” for a square pulse and compare it with the computed electron transit time from the photocathode to the anode. Measured response time for 5 XRD-31s assembled in early 2004 was 149.7 ps +-2.75 ps.

  7. Effect of wind turbine response time on optimal dynamic induction control of wind farms

    NASA Astrophysics Data System (ADS)

    Munters, Wim; Meyers, Johan

    2016-09-01

    In this work, we extend recent research efforts on induction-based optimal control in large-eddy simulations of wind farms in the turbulent atmospheric boundary layer. More precisely, we investigate the effect of wind turbine response time to requested power setpoints on achievable power gains. We do this by including a time-filtering of the thrust coefficient setpoints in the optimal control framework. We consider simulation cases restricted to underinduction compared to the Betz limit, as well as cases that also allow overinduction. Optimization results show that, except for the most restrictive underinductive slow-response case, all cases still yield increases in energy extraction in the order of 10% and more.

  8. Digital redesign of uncertain interval systems based on time-response resemblance via particle swarm optimization.

    PubMed

    Hsu, Chen-Chien; Lin, Geng-Yu

    2009-07-01

    In this paper, a particle swarm optimization (PSO) based approach is proposed to derive an optimal digital controller for redesigned digital systems having an interval plant based on time-response resemblance of the closed-loop systems. Because of difficulties in obtaining time-response envelopes for interval systems, the design problem is formulated as an optimization problem of a cost function in terms of aggregated deviation between the step responses corresponding to extremal energies of the redesigned digital system and those of their continuous counterpart. A proposed evolutionary framework incorporating three PSOs is subsequently presented to minimize the cost function to derive an optimal set of parameters for the digital controller, so that step response sequences corresponding to the extremal sequence energy of the redesigned digital system suitably approximate those of their continuous counterpart under the perturbation of the uncertain plant parameters. Computer simulations have shown that redesigned digital systems incorporating the PSO-derived digital controllers have better system performance than those using conventional open-loop discretization methods.

  9. Linear summation in the barn owl's brainstem underlies responses to interaural time differences.

    PubMed

    Kuokkanen, Paula T; Ashida, Go; Carr, Catherine E; Wagner, Hermann; Kempter, Richard

    2013-07-01

    The neurophonic potential is a synchronized frequency-following extracellular field potential that can be recorded in the nucleus laminaris (NL) in the brainstem of the barn owl. Putative generators of the neurophonic are the afferent axons from the nucleus magnocellularis, synapses onto NL neurons, and spikes of NL neurons. The outputs of NL, i.e., action potentials of NL neurons, are only weakly represented in the neurophonic. Instead, the inputs to NL, i.e., afferent axons and their synaptic potentials, are the predominant origin of the neurophonic (Kuokkanen PT, Wagner H, Ashida G, Carr CE, Kempter R. J Neurophysiol 104: 2274-2290, 2010). Thus in NL the monaural inputs from the two brain sides converge and create a binaural neurophonic. If these monaural inputs contribute independently to the extracellular field, the response to binaural stimulation can be predicted from the sum of the responses to ipsi- and contralateral stimulation. We found that a linear summation model explains the dependence of the responses on interaural time difference as measured experimentally with binaural stimulation. The fit between model predictions and data was excellent, even without taking into account the nonlinear responses of NL coincidence detector neurons, although their firing rate and synchrony strongly depend on the interaural time difference. These results are consistent with the view that the afferent axons and their synaptic potentials in NL are the primary origin of the neurophonic. PMID:23554438

  10. Linear summation in the barn owl's brainstem underlies responses to interaural time differences

    PubMed Central

    Kuokkanen, Paula T.; Ashida, Go; Carr, Catherine E.; Wagner, Hermann

    2013-01-01

    The neurophonic potential is a synchronized frequency-following extracellular field potential that can be recorded in the nucleus laminaris (NL) in the brainstem of the barn owl. Putative generators of the neurophonic are the afferent axons from the nucleus magnocellularis, synapses onto NL neurons, and spikes of NL neurons. The outputs of NL, i.e., action potentials of NL neurons, are only weakly represented in the neurophonic. Instead, the inputs to NL, i.e., afferent axons and their synaptic potentials, are the predominant origin of the neurophonic (Kuokkanen PT, Wagner H, Ashida G, Carr CE, Kempter R. J Neurophysiol 104: 2274–2290, 2010). Thus in NL the monaural inputs from the two brain sides converge and create a binaural neurophonic. If these monaural inputs contribute independently to the extracellular field, the response to binaural stimulation can be predicted from the sum of the responses to ipsi- and contralateral stimulation. We found that a linear summation model explains the dependence of the responses on interaural time difference as measured experimentally with binaural stimulation. The fit between model predictions and data was excellent, even without taking into account the nonlinear responses of NL coincidence detector neurons, although their firing rate and synchrony strongly depend on the interaural time difference. These results are consistent with the view that the afferent axons and their synaptic potentials in NL are the primary origin of the neurophonic. PMID:23554438

  11. Limiting response alternatives in time-intensity scaling: an examination of the halo-dumping effect.

    PubMed

    Clark, C C; Lawless, H T

    1994-12-01

    Time-related measurements pose some challenges to psychophysics and to applied sensory testing methods including control of psychological biases which have been found in single-point scaling. This research examined enhancement of ratings when response alternatives were limited in time-intensity scaling tasks using repeated category ratings. Panelists rated a pseudo-beverage containing sweetener and flavor and one with sweetener only over a 90-s period. The aromatic flavor caused an increase in sweetness intensity and especially so when the panelists were limited to sweetness responses only. The odor-induced enhancement of sweetness was smaller when panelists were given both flavor and sweetness response options than when the panelists were given only a sweetness scale. Prior use of both scales in a previous experimental session did not lessen the halo-dumping enhancement effect. In one study, sweetness ratings of sucrose alone were depressed when the additional scale for flavoring was provided, perhaps due to inappropriate partitioning of responses.

  12. The Effect of Sample Roughness and Planarity on Gauge Response Times

    SciTech Connect

    Proud, W. G.; Wang, J.; Cross, D. L. A.

    2006-07-28

    This study presents a simple analytical approach for determining the significance of sample planarity on its response under extreme pressure. Plate impact experiments are carried out on Copper and PMMA targets of varying roughness and the resulting shock wave are measured with manganin stress gauges. For PMMA, Velocity Interferometer System for Any Reflector (VISAR) and high-speed photography are also used. Results show that the transit times and final stresses reached for both materials are consistent with expected values calculated from the Hugoniot. Samples angled at one degree give an increased rise time consistent with the additional distance traversed by the shock in reaching the gauge.

  13. Safety and Response-Time Analysis of an Automotive Accident Assistance Service

    NASA Astrophysics Data System (ADS)

    Argent-Katwala, Ashok; Clark, Allan; Foster, Howard; Gilmore, Stephen; Mayer, Philip; Tribastone, Mirco

    In the present paper we assess both the safety properties and the response-time profile of a subscription service which provides medical assistance to drivers who are injured in vehicular collisions. We use both timed and untimed process calculi cooperatively to perform the required analysis. The formal analysis tools used are hosted on a high-level modelling platform with support for scripting and orchestration which enables users to build custom analysis processes from the general-purpose analysers which are hosted as services on the platform.

  14. Programming time in serial tapping responses as a function of pathway constraint.

    PubMed

    Sidaway, B; Schoenfelder-Zohdi, B; Moore, B

    1990-01-01

    This study varied the accuracy demand within a linear series of targets to investigate the effect of movement-pathway constraints on response-programming time. Sidaway, Christina, and Shea (1988) have suggested that constraints placed upon movement initiation by the demand for response precision may play an important role in determining the length of the programming process. By varying the subtended angles of a series of three targets, this experiment tested the specific prediction of Sidaway et al. that programming time may be a function of the target, within a line of targets, that subtends the smallest angle at the start position. It is this target that demands the greatest precision in the movement pathway. Subjects participated in a series of conditions in which the size and placement of the target that imposed the maximal constraint was varied. In each condition the subjects were required to strike a series of three targets with a stylus in a simple reaction-time paradigm. Analysis of the reaction-time results revealed a significant effect of size of constraint, but no effect of position of constraint. Analysis of the movement-time data dispelled movement-duration and movement-velocity interpretations of the results and intimated a possible online trajectory-correction process.

  15. Real-time open-loop frequency response analysis of flight test data

    NASA Technical Reports Server (NTRS)

    Bosworth, J. T.; West, J. C.

    1986-01-01

    A technique has been developed to compare the open-loop frequency response of a flight test aircraft real time with linear analysis predictions. The result is direct feedback to the flight control systems engineer on the validity of predictions and adds confidence for proceeding with envelope expansion. Further, gain and phase margins can be tracked for trends in a manner similar to the techniques used by structural dynamics engineers in tracking structural modal damping.

  16. Linear-response calculation in the time-dependent density functional theory

    SciTech Connect

    Nakatsukasa, Takashi; Inakura, Tsunenori; Avogadro, Paolo; Ebata, Shuichiro; Sato, Koichi; Yabana, Kazuhiro

    2012-11-12

    Linear response calculations based on the time-dependent density-functional theory are presented. Especially, we report results of the finite amplitude method which we have recently proposed as an alternative and feasible approach to the (quasiparticle-)random-phase approximation. Calculated properties of the giant resonances and low-energy E1 modes are discussed. We found a universal linear correlation between the low-energy E1 strength and the neutron skin thickness.

  17. Nonlinear response - A time domain approach. [with applications to acoustic fatigue, spacecraft and composite materials

    NASA Technical Reports Server (NTRS)

    Vaicaitis, R.

    1986-01-01

    The present paper reviews the basic concepts of nonlinear response of panels to surface flow and acoustic pressures, simulation of random processes, time domain solutions and the Monte Carlo Method. Applications of this procedure to the orbit-on-demand space vehicles, acoustic fatigue and composite materials are discussed. Numerical examples are included for a variety of nonlinear problems to illustrate the applicability of this method.

  18. Time and dose-response effects of honokiol on UVB-induced skin cancer development.

    PubMed

    Guillermo, Ruth F; Chilampalli, Chandeshwari; Zhang, Xiaoying; Zeman, David; Fahmy, Hesham; Dwivedi, Chandradhar

    2012-06-01

    Honokiol has shown chemopreventive effects in chemically-induced and UVB-induced skin cancer in mice. In this investigation, we assessed the time-effects of a topical low dose of honokiol (30 μg), and then the effects of different honokiol doses (30, 45, and 60 μg) on a UVB-induced skin cancer model to find an optimal dose and time for desirable chemopreventive effects. UVB radiation (30 mJ/cm(2), 5 days/week for 25 or 27 weeks) was used to induce skin carcinogenesis in SKH-1 mice. For the time-response experiment 30 μg honokiol in acetone was applied topically to the animals before the UVB exposure (30 min, 1 h, and 2 h) and after the UVB exposure (immediately, 30 min, and 1 h). Control groups were treated with acetone. For the dose-response study, animals were treated topically with acetone or honokiol (30, 45, and 60 μg) one hour before the UVB exposure. In the time-response experiment, honokiol inhibited skin tumor multiplicity by 49-58% while reducing tumor volumes by 70-89%. In the dose-response study, honokiol (30, 45, and 60 μg) significantly decreased skin tumor multiplicity by 36-78% in a dose-dependent manner, while tumor area was reduced by 76-94%. Honokiol (60 μg) significantly reduced tumor incidence by 40% as compared to control group. Honokiol applied in very low doses (30 μg) either before or after UVB radiation shows chemopreventive effects. Honokiol (30, 45, and 60 μg) prevents UVB-induced skin cancer in a dose-dependent manner. Honokiol can be an effective chemopreventive agent against skin cancer.

  19. Imaging the cellular response to transient shear stress using time-resolved digital holography

    NASA Astrophysics Data System (ADS)

    Arita, Yoshihiko; Antkowiak, Maciej; Gunn-Moore, Frank; Dholakia, Kishan

    2014-02-01

    Shear stress has been recognized as one of the biophysical methods by which to permeabilize plasma membranes of cells. In particular, high pressure transient hydrodynamic flows created by laser-induced cavitation have been shown to lead to the uptake of fluorophores and plasmid DNA. While the mechanism and dynamics of cavitation have been extensively studied using a variety of time-resolved imaging techniques, the cellular response to the cavitation bubble and cavitation induced transient hydrodynamic flows has never been shown in detail. We use time-resolved quantitative phase microscopy to study cellular response to laser-induced cavitation bubbles. Laser-induced breakdown of an optically trapped polystyrene nanoparticle (500nm in diameter) irradiated with a single nanosecond laser pulse at 532nm creates transient shear stress to surrounding cells without causing cell lysis. A bi-directional transient displacement of cytoplasm is observed during expansion and collapse of the cavitation bubble. In some cases, cell deformation is only observable at the microsecond time scale without any permanent change in cell shape or optical thickness. On a time scale of seconds, the cellular response to shear stress and cytoplasm deformation typically leads to retraction of the cellular edge most exposed to the flow, rounding of the cell body and, in some cases, loss of cellular dry mass. These results give a new insight into the cellular response to laser-induced shear stress and related plasma membrane permeabilization. This study also demonstrates that laser-induced breakdown of an optically trapped nanoparticle offers localized cavitation (70 μm in diameter), which interacts with a single cell.

  20. Sampling frequency, response times and embedded signal filtration in fast, high efficiency liquid chromatography: A tutorial.

    PubMed

    Wahab, M Farooq; Dasgupta, Purnendu K; Kadjo, Akinde F; Armstrong, Daniel W

    2016-02-11

    With increasingly efficient columns, eluite peaks are increasingly narrower. To take full advantage of this, choice of the detector response time and the data acquisition rate a.k.a. detector sampling frequency, have become increasingly important. In this work, we revisit the concept of data sampling from the theorem variously attributed to Whittaker, Nyquist, Kotelnikov, and Shannon. Focusing on time scales relevant to the current practice of high performance liquid chromatography (HPLC) and optical absorbance detection (the most commonly used method), even for very narrow simulated peaks Fourier transformation shows that theoretical minimum sampling frequency is still relatively low (<10 Hz). However, this consideration alone may not be adequate for real chromatograms when an appreciable amount of noise is present. Further, depending on the instrument, the manufacturer's choice of a particular data bunching/integration/response time condition may be integrally coupled to the sampling frequency. In any case, the exact nature of signal filtration often occurs in a manner neither transparent to nor controllable by the user. Using fast chromatography on a state-of-the-art column (38,000 plates), we evaluate the responses produced by different present generation instruments, each with their unique black box digital filters. We show that the common wisdom of sampling 20 points per peak can be inadequate for high efficiency columns and that the sampling frequency and response choices do affect the peak shape. If the sampling frequency is too low or response time is too large, the observed peak shapes will not remain as narrow as they really are - this is especially true for high efficiency and high speed separations. It is shown that both sampling frequency and digital filtering affect the retention time, noise amplitude, peak shape and width in a complex fashion. We show how a square-wave driven light emitting diode source can reveal the nature of the embedded filter

  1. Sampling frequency, response times and embedded signal filtration in fast, high efficiency liquid chromatography: A tutorial.

    PubMed

    Wahab, M Farooq; Dasgupta, Purnendu K; Kadjo, Akinde F; Armstrong, Daniel W

    2016-02-11

    With increasingly efficient columns, eluite peaks are increasingly narrower. To take full advantage of this, choice of the detector response time and the data acquisition rate a.k.a. detector sampling frequency, have become increasingly important. In this work, we revisit the concept of data sampling from the theorem variously attributed to Whittaker, Nyquist, Kotelnikov, and Shannon. Focusing on time scales relevant to the current practice of high performance liquid chromatography (HPLC) and optical absorbance detection (the most commonly used method), even for very narrow simulated peaks Fourier transformation shows that theoretical minimum sampling frequency is still relatively low (<10 Hz). However, this consideration alone may not be adequate for real chromatograms when an appreciable amount of noise is present. Further, depending on the instrument, the manufacturer's choice of a particular data bunching/integration/response time condition may be integrally coupled to the sampling frequency. In any case, the exact nature of signal filtration often occurs in a manner neither transparent to nor controllable by the user. Using fast chromatography on a state-of-the-art column (38,000 plates), we evaluate the responses produced by different present generation instruments, each with their unique black box digital filters. We show that the common wisdom of sampling 20 points per peak can be inadequate for high efficiency columns and that the sampling frequency and response choices do affect the peak shape. If the sampling frequency is too low or response time is too large, the observed peak shapes will not remain as narrow as they really are - this is especially true for high efficiency and high speed separations. It is shown that both sampling frequency and digital filtering affect the retention time, noise amplitude, peak shape and width in a complex fashion. We show how a square-wave driven light emitting diode source can reveal the nature of the embedded filter

  2. Sub-Millisecond Response Time in a Photorefractive Composite Operating under CW Conditions

    NASA Astrophysics Data System (ADS)

    Moon, Jong-Sik; Stevens, Tyler E.; Monson, Todd C.; Huber, Dale L.; Jin, Sung-Ho; Oh, Jin-Woo; Winiarz, Jeffrey G.

    2016-08-01

    Extensive study of photorefractive polymeric composites photosensitized with semiconductor nanocrystals has yielded data indicating that the inclusion of such nanocrystals enhances the charge-carrier mobility, and subsequently leads to a reduction in the photorefractive response time. Unfortunately, the included nanocrystals may also act as a source of deep traps, resulting in diminished diffraction efficiencies as well as reduced two beam coupling gain coefficients. Nonetheless, previous studies indicate that this problem is mitigated through the inclusion of semiconductor nanocrystals possessing a relatively narrow band-gap. Here, we fully exploit this property by doping PbS nanocrystals into a newly formulated photorefractive composite based on molecular triphenyldiamine photosensitized with C60. Through this approach, response times of 399 μs are observed, opening the door for video and other high-speed applications. It is further demonstrated that this improvement in response time occurs with little sacrifice in photorefractive efficiency, with internal diffraction efficiencies of 72% and two-beam-coupling gain coefficients of 500 cm‑1 being measured. A thorough analysis of the experimental data is presented, supporting the hypothesized mechanism of enhanced charge mobility without the accompaniment of superfluous traps. It is anticipated that this approach can play a significant role in the eventual commercialization of this class of materials.

  3. A Gravity-Responsive Time-Keeping Protein of the Plant and Animal Cell Surface

    NASA Technical Reports Server (NTRS)

    Morre, D. James

    2003-01-01

    The hypothesis under investigation was that a ubiquinol (NADH) oxidase protein of the cell surface with protein disulfide-thiol interchange activity (= NOX protein) is a plant and animal time-keeping ultradian (period of less than 24 h) driver of both cell enlargement and the biological clock that responds to gravity. Despite considerable work in a large number of laboratories spanning several decades, this is, to my knowledge, our work is the first demonstration of a time-keeping biochemical reaction that is both gravity-responsive and growth-related and that has been shown to determine circadian periodicity. As such, the NOX protein may represent both the long-sought biological gravity receptor and the core oscillator of the cellular biological clock. Completed studies have resulted in 12 publications and two issued NASA-owned patents of the clock activity. The gravity response and autoentrainment were characterized in cultured mammalian cells and in two plant systems together with entrainment by light and small molecules (melatonin). The molecular basis of the oscillatory behavior was investigated using spectroscopic methods (Fourier transform infrared and circular dichroism) and high resolution electron microscopy. We have also applied these findings to an understanding of the response to hypergravity. Statistical methods for analysis of time series phenomena were developed (Foster et al., 2003).

  4. Effects of Short-Term Physical Activity Interventions on Simple and Choice Response Times

    PubMed Central

    Norton, Kevin; Norton, Lynda; Lewis, Nicole

    2016-01-01

    Objective. Response time (RT) is important for health and human performance and provides insight into cognitive processes. It deteriorates with age, is associated with chronic physical activity (PA), and improves with PA interventions. We investigated associations between the amount and type of PA undertaken and the rate of change in RT for low-active adults across the age range 18–63 yr. Methods. Insufficiently active adults were assigned to either a walking (n = 263) or higher-intensity (n = 380) exercise program conducted over 40 days. Active controls were also recruited (n = 135). Simple response time (SRT) and choice response time (CRT) were measured before and after the intervention and at 3-, 6-, and 12-month follow-up. Results. SRT and CRT slowed across the age range; however, habitually active participants at baseline had significantly faster CRT (p < 0.05). The interventions increased weekly PA with corresponding increases in physical fitness. These changes were mirrored in faster CRT across the study for both intervention groups (p < 0.05). No changes were found for SRT. Conclusions. Both PA interventions resulted in improvements in CRT among adults starting from a low activity base. These improvements were relatively rapid and occurred in both interventions despite large differences in exercise volume, type, and intensity. There were no effects on SRT in either intervention. PMID:27190993

  5. Sub-Millisecond Response Time in a Photorefractive Composite Operating under CW Conditions

    PubMed Central

    Moon, Jong-Sik; Stevens, Tyler E.; Monson, Todd C.; Huber, Dale L.; Jin, Sung-Ho; Oh, Jin-Woo; Winiarz, Jeffrey G.

    2016-01-01

    Extensive study of photorefractive polymeric composites photosensitized with semiconductor nanocrystals has yielded data indicating that the inclusion of such nanocrystals enhances the charge-carrier mobility, and subsequently leads to a reduction in the photorefractive response time. Unfortunately, the included nanocrystals may also act as a source of deep traps, resulting in diminished diffraction efficiencies as well as reduced two beam coupling gain coefficients. Nonetheless, previous studies indicate that this problem is mitigated through the inclusion of semiconductor nanocrystals possessing a relatively narrow band-gap. Here, we fully exploit this property by doping PbS nanocrystals into a newly formulated photorefractive composite based on molecular triphenyldiamine photosensitized with C60. Through this approach, response times of 399 μs are observed, opening the door for video and other high-speed applications. It is further demonstrated that this improvement in response time occurs with little sacrifice in photorefractive efficiency, with internal diffraction efficiencies of 72% and two-beam-coupling gain coefficients of 500 cm−1 being measured. A thorough analysis of the experimental data is presented, supporting the hypothesized mechanism of enhanced charge mobility without the accompaniment of superfluous traps. It is anticipated that this approach can play a significant role in the eventual commercialization of this class of materials. PMID:27478156

  6. Sub-millisecond response time in a photorefractive composite operating under CW conditions

    DOE PAGES

    Moon, Jong -Sik; Stevens, Tyler E.; Monson, Todd C.; Huber, Dale L.; Jin, Sung -Ho; Oh, Jin -Woo; Winiarz, Jeffrey G.

    2016-08-01

    Extensive study of photorefractive polymeric composites photosensitized with semiconductor nanocrystals has yielded data indicating that the inclusion of such nanocrystals enhances the charge-carrier mobility, and subsequently leads to a reduction in the photorefractive response time. Unfortunately, the included nanocrystals may also act as a source of deep traps, resulting in diminished diffraction efficiencies as well as reduced two beam coupling gain coefficients. Nonetheless, previous studies indicate that this problem is mitigated through the inclusion of semiconductor nanocrystals possessing a relatively narrow band-gap. Here, we fully exploit this property by doping PbS nanocrystals into a newly formulated photorefractive composite based onmore » molecular triphenyldiamine photosensitized with C60. Through this approach, response times of 399 μs are observed, opening the door for video and other high-speed applications. It is further demonstrated that this improvement in response time occurs with little sacrifice in photorefractive efficiency, with internal diffraction efficiencies of 72% and two-beam-coupling gain coefficients of 500 cm–1 being measured. A thorough analysis of the experimental data is presented, supporting the hypothesized mechanism of enhanced charge mobility without the accompaniment of superfluous traps. As a result, it is anticipated that this approach can play a significant role in the eventual commercialization of this class of materials.« less

  7. Time Domains of the Hypoxic Ventilatory Response and Their Molecular Basis

    PubMed Central

    Pamenter, Matthew E.; Powell, Frank L.

    2016-01-01

    Ventilatory responses to hypoxia vary widely depending on the pattern and length of hypoxic exposure. Acute, prolonged, or intermittent hypoxic episodes can increase or decrease breathing for seconds to years, both during the hypoxic stimulus, and also after its removal. These myriad effects are the result of a complicated web of molecular interactions that underlie plasticity in the respiratory control reflex circuits and ultimately control the physiology of breathing in hypoxia. Since the time domains of the physiological hypoxic ventilatory response (HVR) were identified, considerable research effort has gone toward elucidating the underlying molecular mechanisms that mediate these varied responses. This research has begun to describe complicated and plastic interactions in the relay circuits between the peripheral chemoreceptors and the ventilatory control circuits within the central nervous system. Intriguingly, many of these molecular pathways seem to share key components between the different time domains, suggesting that varied physiological HVRs are the result of specific modifications to overlapping pathways. This review highlights what has been discovered regarding the cell and molecular level control of the time domains of the HVR, and highlights key areas where further research is required. Understanding the molecular control of ventilation in hypoxia has important implications for basic physiology and is emerging as an important component of several clinical fields. PMID:27347896

  8. Sub-Millisecond Response Time in a Photorefractive Composite Operating under CW Conditions.

    PubMed

    Moon, Jong-Sik; Stevens, Tyler E; Monson, Todd C; Huber, Dale L; Jin, Sung-Ho; Oh, Jin-Woo; Winiarz, Jeffrey G

    2016-01-01

    Extensive study of photorefractive polymeric composites photosensitized with semiconductor nanocrystals has yielded data indicating that the inclusion of such nanocrystals enhances the charge-carrier mobility, and subsequently leads to a reduction in the photorefractive response time. Unfortunately, the included nanocrystals may also act as a source of deep traps, resulting in diminished diffraction efficiencies as well as reduced two beam coupling gain coefficients. Nonetheless, previous studies indicate that this problem is mitigated through the inclusion of semiconductor nanocrystals possessing a relatively narrow band-gap. Here, we fully exploit this property by doping PbS nanocrystals into a newly formulated photorefractive composite based on molecular triphenyldiamine photosensitized with C60. Through this approach, response times of 399 μs are observed, opening the door for video and other high-speed applications. It is further demonstrated that this improvement in response time occurs with little sacrifice in photorefractive efficiency, with internal diffraction efficiencies of 72% and two-beam-coupling gain coefficients of 500 cm(-1) being measured. A thorough analysis of the experimental data is presented, supporting the hypothesized mechanism of enhanced charge mobility without the accompaniment of superfluous traps. It is anticipated that this approach can play a significant role in the eventual commercialization of this class of materials. PMID:27478156

  9. Viewing time effects revisited: prolonged response latencies for sexually attractive targets under restricted task conditions.

    PubMed

    Imhoff, Roland; Schmidt, Alexander F; Nordsiek, Uta; Luzar, Charlotte; Young, Andrew W; Banse, Rainer

    2010-12-01

    Sexually attractive stimuli are watched longer than unattractive stimuli. The processes underlying this robust and reliable viewing time effect are presently not well understood. In the present research comprising four experiments (total N = 250), four classes of potential explanations are proposed and the derived implications were experimentally tested. Contrary to explanations based on either deliberate delay or attentional adhesion to sexually attractive stimuli, prolonged response latencies were also found under restricted task conditions. Sexually preferred targets elicited longer response latencies in a self-paced evaluation task when stimulus pictures were presented for 750 ms (Experiment 1) or for 500 ms and followed by a pattern mask (Experiment 2). Prolonged latencies for sexually preferred targets were also observed when sexual attractiveness was rated in a speeded binary decision task with a response window of 1000 ms (Experiment 3). Eventually, it was shown that the response latency effect in the speeded binary choice task was still preserved when only the heads of target individuals were presented instead of the bodies (Experiment 4). Mate identification and schematic processes are discussed as the remaining plausible mechanisms for prolonged response latencies for sexually attractive targets under restricted conditions. PMID:20198414

  10. The timing of galvanic vestibular stimulation affects responses to platform translation

    NASA Technical Reports Server (NTRS)

    Hlavacka, F.; Shupert, C. L.; Horak, F. B.; Peterson, B. W. (Principal Investigator)

    1999-01-01

    We compared the effects of galvanic vestibular stimulation applied at 0, 0.5, 1.5 and 2.5 s prior to a backward platform translation on postural responses. The effect of the galvanic stimulation was largest on the final equilibrium position of the center of pressure (CoP). The largest effects occurred for the 0.5 and 0-s pre-period, when the dynamic CoP pressure changes in response to both the galvanic stimulus and the platform translation coincided. The shift in the final equilibrium position was also larger than the sum of the shifts for the galvanic stimulus and the platform translation alone for the 0.5 and 0-s pre-periods. The initial rate of change of the CoP response to the platform translation was not significantly affected in any condition. Changes in the peak CoP position could be accounted for by local interaction of CoP velocity changes induced by the galvanic and translation responses alone, but the changes in final equilibrium position could only be accounted for by a change in global body orientation. These findings suggest that the contribution of vestibulospinal information is greatest during the dynamic phase of the postural response, and that the vestibular system contributes most to the later components of the postural response, particularly to the final equilibrium position. These findings suggest that a nonlinear interaction between the vestibular signal induced by the galvanic current and the sensory stimuli produced by the platform translation occurs when the two stimuli are presented within 1 s, during the dynamic phase of the postural response to the galvanic stimulus. When presented at greater separations in time, the stimuli appear to be treated as independent events, such that no interaction occurs. Copyright 1999 Elsevier Science B.V.

  11. 33 CFR 155.4055 - Temporary waivers from meeting one or more of the specified response times.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... specific response time requirement, if you are unable to identify a resource provider who can meet the response time. (b) Your request must be specific as to the COTP zone, operating environment, salvage or... waiver request, the operating environment, and other relevant factors. These time periods are listed...

  12. Prediction, time variance, and classification of hydraulic response to recharge in two karst aquifers

    USGS Publications Warehouse

    Long, Andrew J.; Mahler, Barbara J.

    2013-01-01

    Many karst aquifers are rapidly filled and depleted and therefore are likely to be susceptible to changes in short-term climate variability. Here we explore methods that could be applied to model site-specific hydraulic responses, with the intent of simulating these responses to different climate scenarios from high-resolution climate models. We compare hydraulic responses (spring flow, groundwater level, stream base flow, and cave drip) at several sites in two karst aquifers: the Edwards aquifer (Texas, USA) and the Madison aquifer (South Dakota, USA). A lumped-parameter model simulates nonlinear soil moisture changes for estimation of recharge, and a time-variant convolution model simulates the aquifer response to this recharge. Model fit to data is 2.4% better for calibration periods than for validation periods according to the Nash–Sutcliffe coefficient of efficiency, which ranges from 0.53 to 0.94 for validation periods. We use metrics that describe the shapes of the impulse-response functions (IRFs) obtained from convolution modeling to make comparisons in the distribution of response times among sites and between aquifers. Time-variant IRFs were applied to 62% of the sites. Principal component analysis (PCA) of metrics describing the shapes of the IRFs indicates three principal components that together account for 84% of the variability in IRF shape: the first is related to IRF skewness and temporal spread and accounts for 51% of the variability; the second and third largely are related to time-variant properties and together account for 33% of the variability. Sites with IRFs that dominantly comprise exponential curves are separated geographically from those dominantly comprising lognormal curves in both aquifers as a result of spatial heterogeneity. The use of multiple IRF metrics in PCA is a novel method to characterize, compare, and classify the way in which different sites and aquifers respond to recharge. As convolution models are developed for

  13. Leisure Time Physical Activity and Mortality: A Detailed Pooled Analysis of the Dose-Response Relationship

    PubMed Central

    Arem, Hannah; Moore, Steven C.; Patel, Alpa; Hartge, Patricia; de Gonzalez, Amy Berrington; Visvanathan, Kala; Campbell, Peter T.; Freedman, Michal; Weiderpass, Elisabete; Adami, Hans Olov; Linet, Martha S.; Lee, I-Min; Matthews, Charles E.

    2015-01-01

    Importance The 2008 Physical Activity Guidelines for Americans recommended a minimum of 75 vigorous-intensity or 150 moderate-intensity minutes per week (7.5 metabolic equivalent hours per week (MET h/wk)) of aerobic activity for “substantial” health benefit, and suggested “additional” benefits by doing more than double this amount. However, the upper limit of longevity benefit or possible harm with more physical activity is unclear. Objective To quantify the dose-response association between leisure-time physical activity and mortality, and to define the upper limit of benefit or harm associated with more physical activity. Design We pooled data from six studies in the NCI Cohort Consortium (baseline 1992–2003). We used Cox proportional hazards regression with cohort stratification to generate multivariable-adjusted hazard ratios (HR) and 95% confidence intervals (CI). Median follow-up time was 14.2 years. Setting Population-based prospective cohorts in the U.S. and Europe with self-reported physical activity. Participants 661,137 men and women (116,686 deaths); median age 62 (range 21–98) years. Exposure Leisure-time moderate- to vigorous-intensity physical activity Main Outcome Mortality Results Compared to those reporting no leisure-time physical activity, we observed a 20% lower mortality risk among those performing less than the recommended 7.5 MET h/wk minimum (HR=0.80, 95% CI 0.78–0.82), a 31% lower risk at 1–2 times the recommended minimum (0.69, 0.67–0.70), and a 37% lower risk at 2–3 times the minimum (0.63, 0.62–0.65). An upper threshold for mortality benefit occurred at 3–5 times the physical activity recommendation (0.61, 0.59–0.62), but compared to the recommended minimum, the additional benefit was modest (31% vs. 39%). There was no evidence of harm at 10+ times the recommended minimum (0.68, 0.59–0.78). A similar dose-response was observed for mortality due to cardiovascular disease and to cancer. Conclusions and

  14. On cell resistance and immune response time lag in a model for the HIV infection

    NASA Astrophysics Data System (ADS)

    Solovey, Guillermo; Peruani, Fernando; Ponce Dawson, Silvina; Maria Zorzenon dos Santos, Rita

    2004-11-01

    Recently, a cellular automata model has been introduced (Phys. Rev. Lett. 87 (2001) 168102) to describe the spread of the HIV infection among target cells in lymphoid tissues. The model reproduces qualitatively the entire course of the infection displaying, in particular, the two time scales that characterize its dynamics. In this work, we investigate the robustness of the model against changes in three of its parameters. Two of them are related to the resistance of the cells to get infected. The other one describes the time interval necessary to mount specific immune responses. We have observed that an increase of the cell resistance, at any stage of the infection, leads to a reduction of the latency period, i.e., of the time interval between the primary infection and the onset of AIDS. However, during the early stages of the infection, when the cell resistance increase is combined with an increase in the initial concentration of infected cells, the original behavior is recovered. Therefore we find a long and a short latency regime (eight and one year long, respectively) depending on the value of the cell resistance. We have obtained, on the other hand, that changes on the parameter that describes the immune system time lag affects the time interval during which the primary infection occurs. Using different extended versions of the model, we also discuss how the two-time scale dynamics is affected when we include inhomogeneities on the cells properties, as for instance, on the cell resistance or on the time interval to mount specific immune responses.

  15. Competition for antigen between Th1 and Th2 responses determines the timing of the immune response switch during Mycobaterium avium subspecies paratuberulosis infection in ruminants.

    PubMed

    Magombedze, Gesham; Eda, Shigetoshi; Ganusov, Vitaly V

    2014-01-01

    Johne's disease (JD), a persistent and slow progressing infection of ruminants such as cows and sheep, is caused by slow replicating bacilli Mycobacterium avium subspecies paratuberculosis (MAP) infecting macrophages in the gut. Infected animals initially mount a cell-mediated CD4 T cell response against MAP which is characterized by the production of interferon gamma (Th1 response). Over time, Th1 response diminishes in most animals and antibody response to MAP antigens becomes dominant (Th2 response). The switch from Th1 to Th2 response occurs concomitantly with disease progression and shedding of the bacteria in feces. Mechanisms controlling this Th1/Th2 switch remain poorly understood. Because Th1 and Th2 responses are known to cross-inhibit each other, it is unclear why initially strong Th1 response is lost over time. Using a novel mathematical model of the immune response to MAP infection we show that the ability of extracellular bacteria to persist outside of macrophages naturally leads to switch of the cellular response to antibody production. Several additional mechanisms may also contribute to the timing of the Th1/Th2 switch including the rate of proliferation of Th1/Th2 responses at the site of infection, efficiency at which immune responses cross-inhibit each other, and the rate at which Th1 response becomes exhausted over time. Our basic model reasonably well explains four different kinetic patterns of the Th1/Th2 responses in MAP-infected sheep by variability in the initial bacterial dose and the efficiency of the MAP-specific T cell responses. Taken together, our novel mathematical model identifies factors of bacterial and host origin that drive kinetics of the immune response to MAP and provides the basis for testing the impact of vaccination or early treatment on the duration of infection. PMID:24415928

  16. Modeling of time-dependent force response of fingertip to dynamic loading.

    PubMed

    Wu, J Z; Dong, R G; Smutz, W P; Schopper, A W

    2003-03-01

    An extended exposure to repeated loading on fingertip has been associated to many vascular, sensorineural, and musculoskeletal disorders in the fingers, such as carpal tunnel syndrome, hand-arm vibration syndrome, and flexor tenosynovitis. A better understanding of the pathomechanics of these sensorineural and vascular diseases in fingers requires a formulation of a biomechanical model of the fingertips and analyses to predict the mechanical responses of the soft tissues to dynamic loading. In the present study, a model based on finite element techniques has been developed to simulate the mechanical responses of the fingertips to dynamic loading. The proposed model is two-dimensional and incorporates the essential anatomical structures of a finger: skin, subcutaneous tissue, bone, and nail. The skin tissue is assumed to be hyperelastic and viscoelastic. The subcutaneous tissue was considered to be a nonlinear, biphasic material composed of a hyperelastic solid and an invicid fluid, while its hydraulic permeability was considered to be deformation dependent. Two series of numerical tests were performed using the proposed finger tip model to: (a) simulate the responses of the fingertip to repeated loading, where the contact plate was assumed to be fixed, and the bone within the fingertip was subjected to a prescribed sinusoidal displacement in vertical direction; (b) simulate the force response of the fingertip in a single keystroke, where the keyboard was composed of a hard plastic keycap, a rigid support block, and a nonlinear spring. The time-dependent behavior of the fingertip under dynamic loading was derived. The model predictions of the time-histories of force response of the fingertip and the phenomenon of fingertip separation from the contacting plate during cyclic loading agree well with the reported experimental observations.

  17. Physiological demands of women's rugby union: time-motion analysis and heart rate response.

    PubMed

    Virr, Jody Lynn; Game, Alex; Bell, Gordon John; Syrotuik, Daniel

    2014-01-01

    The aim of this study was to determine the physical demands of women's rugby union match play using time-motion analysis and heart rate (HR) response. Thirty-eight premier club level female rugby players, ages 18-34 years were videotaped and HRs monitored for a full match. Performances were coded into 12 different movement categories: 5 speeds of locomotion (standing, walking, jogging, striding, sprinting), 4 forms of intensive non-running exertion (ruck/maul/tackle, pack down, scrum, lift) and 3 discrete activities (kick, jump, open field tackle). The main results revealed that backs spend significantly more time sprinting and walking whereas forwards spend more time in intensive non-running exertion and jogging. Forwards also had a significantly higher total work frequency compared to the backs, but a higher total rest frequency compared to the backs. In terms of HR responses, forwards displayed higher mean HRs throughout the match and more time above 80% of their maximum HR than backs. In summary, women's rugby union is characterised by intermittent bursts of high-intensity activity, where forwards and backs have similar anaerobic energy demands, but different specific match demands.

  18. Rasch analysis for the evaluation of rank of student response time in multiple choice examinations.

    PubMed

    Thompson, James J; Yang, Tong; Chauvin, Sheila W

    2013-01-01

    The availability of computerized testing has broadened the scope of person assessment beyond the usual accuracy-ability domain to include response time analyses. Because there are contexts in which speed is important, e.g. medical practice, it is important to develop tools by which individuals can be evaluated for speed. In this paper, the ability of Rasch measurement to convert ordinal nonparametric rankings of speed to measures is examined and compared to similar measures derived from parametric analysis of response times (pace) and semi-parametric logarithmic time-scaling procedures. Assuming that similar spans of the measures were used, non-parametric methods of raw ranking or percentile-ranking of persons by questions gave statistically acceptable person estimates of speed virtually identical to the parametric or semi-parametric methods. Because no assumptions were made about the underlying time distributions with ranking, generality of conclusions was enhanced. The main drawbacks of the non-parametric ranking procedures were the lack of information on question duration and the overall assignment by the model of variance to the person by question interaction.

  19. Real-time fluorescence imaging of the DNA damage repair response during mitosis.

    PubMed

    Miwa, Shinji; Yano, Shuya; Yamamoto, Mako; Matsumoto, Yasunori; Uehara, Fuminari; Hiroshima, Yukihiko; Toneri, Makoto; Murakami, Takashi; Kimura, Hiroaki; Hayashi, Katsuhiro; Yamamoto, Norio; Efimova, Elena V; Tsuchiya, Hiroyuki; Hoffman, Robert M

    2015-04-01

    The response to DNA damage during mitosis was visualized using real-time fluorescence imaging of focus formation by the DNA-damage repair (DDR) response protein 53BP1 linked to green fluorescent protein (GFP) (53BP1-GFP) in the MiaPaCa-2(Tet-On) pancreatic cancer cell line. To observe 53BP1-GFP foci during mitosis, MiaPaCa-2(Tet-On) 53BP1-GFP cells were imaged every 30 min by confocal microscopy. Time-lapse imaging demonstrated that 11.4 ± 2.1% of the mitotic MiaPaCa-2(Tet-On) 53BP1-GFP cells had increased focus formation over time. Non-mitotic cells did not have an increase in 53BP1-GFP focus formation over time. Some of the mitotic MiaPaCa-2(Tet-On) 53BP1-GFP cells with focus formation became apoptotic. The results of the present report suggest that DNA strand breaks occur during mitosis and undergo repair, which may cause some of the mitotic cells to enter apoptosis in a phenomenon possibly related to mitotic catastrophe.

  20. Physiological demands of women's rugby union: time-motion analysis and heart rate response.

    PubMed

    Virr, Jody Lynn; Game, Alex; Bell, Gordon John; Syrotuik, Daniel

    2014-01-01

    The aim of this study was to determine the physical demands of women's rugby union match play using time-motion analysis and heart rate (HR) response. Thirty-eight premier club level female rugby players, ages 18-34 years were videotaped and HRs monitored for a full match. Performances were coded into 12 different movement categories: 5 speeds of locomotion (standing, walking, jogging, striding, sprinting), 4 forms of intensive non-running exertion (ruck/maul/tackle, pack down, scrum, lift) and 3 discrete activities (kick, jump, open field tackle). The main results revealed that backs spend significantly more time sprinting and walking whereas forwards spend more time in intensive non-running exertion and jogging. Forwards also had a significantly higher total work frequency compared to the backs, but a higher total rest frequency compared to the backs. In terms of HR responses, forwards displayed higher mean HRs throughout the match and more time above 80% of their maximum HR than backs. In summary, women's rugby union is characterised by intermittent bursts of high-intensity activity, where forwards and backs have similar anaerobic energy demands, but different specific match demands. PMID:24168428

  1. Rasch analysis for the evaluation of rank of student response time in multiple choice examinations.

    PubMed

    Thompson, James J; Yang, Tong; Chauvin, Sheila W

    2013-01-01

    The availability of computerized testing has broadened the scope of person assessment beyond the usual accuracy-ability domain to include response time analyses. Because there are contexts in which speed is important, e.g. medical practice, it is important to develop tools by which individuals can be evaluated for speed. In this paper, the ability of Rasch measurement to convert ordinal nonparametric rankings of speed to measures is examined and compared to similar measures derived from parametric analysis of response times (pace) and semi-parametric logarithmic time-scaling procedures. Assuming that similar spans of the measures were used, non-parametric methods of raw ranking or percentile-ranking of persons by questions gave statistically acceptable person estimates of speed virtually identical to the parametric or semi-parametric methods. Because no assumptions were made about the underlying time distributions with ranking, generality of conclusions was enhanced. The main drawbacks of the non-parametric ranking procedures were the lack of information on question duration and the overall assignment by the model of variance to the person by question interaction. PMID:24064578

  2. Time dependent viscoelastic rheological response of pure, modified and synthetic bituminous binders

    NASA Astrophysics Data System (ADS)

    Airey, G. D.; Grenfell, J. R. A.; Apeagyei, A.; Subhy, A.; Lo Presti, D.

    2016-08-01

    Bitumen is a viscoelastic material that exhibits both elastic and viscous components of response and displays both a temperature and time dependent relationship between applied stresses and resultant strains. In addition, as bitumen is responsible for the viscoelastic behaviour of all bituminous materials, it plays a dominant role in defining many of the aspects of asphalt road performance, such as strength and stiffness, permanent deformation and cracking. Although conventional bituminous materials perform satisfactorily in most highway pavement applications, there are situations that require the modification of the binder to enhance the properties of existing asphalt material. The best known form of modification is by means of polymer modification, traditionally used to improve the temperature and time susceptibility of bitumen. Tyre rubber modification is another form using recycled crumb tyre rubber to alter the properties of conventional bitumen. In addition, alternative binders (synthetic polymeric binders as well as renewable, environmental-friendly bio-binders) have entered the bitumen market over the last few years due to concerns over the continued availability of bitumen from current crudes and refinery processes. This paper provides a detailed rheological assessment, under both temperature and time regimes, of a range of conventional, modified and alternative binders in terms of the materials dynamic (oscillatory) viscoelastic response. The rheological results show the improved viscoelastic properties of polymer- and rubber-modified binders in terms of increased complex shear modulus and elastic response, particularly at high temperatures and low frequencies. The synthetic binders were found to demonstrate complex rheological behaviour relative to that seen for conventional bituminous binders.

  3. Body size and activity times mediate mammalian responses to climate change.

    PubMed

    McCain, Christy M; King, Sarah R B

    2014-06-01

    Model predictions of extinction risks from anthropogenic climate change are dire, but still overly simplistic. To reliably predict at-risk species we need to know which species are currently responding, which are not, and what traits are mediating the responses. For mammals, we have yet to identify overarching physiological, behavioral, or biogeographic traits determining species' responses to climate change, but they must exist. To date, 73 mammal species in North America and eight additional species worldwide have been assessed for responses to climate change, including local extirpations, range contractions and shifts, decreased abundance, phenological shifts, morphological or genetic changes. Only 52% of those species have responded as expected, 7% responded opposite to expectations, and the remaining 41% have not responded. Which mammals are and are not responding to climate change is mediated predominantly by body size and activity times (phylogenetic multivariate logistic regressions, P < 0.0001). Large mammals respond more, for example, an elk is 27 times more likely to respond to climate change than a shrew. Obligate diurnal and nocturnal mammals are more than twice as likely to respond as mammals with flexible activity times (P < 0.0001). Among the other traits examined, species with higher latitudinal and elevational ranges were more likely to respond to climate change in some analyses, whereas hibernation, heterothermy, burrowing, nesting, and study location did not influence responses. These results indicate that some mammal species can behaviorally escape climate change whereas others cannot, analogous to paleontology's climate sheltering hypothesis. Including body size and activity flexibility traits into future extinction risk forecasts should substantially improve their predictive utility for conservation and management. PMID:24449019

  4. Body size and activity times mediate mammalian responses to climate change.

    PubMed

    McCain, Christy M; King, Sarah R B

    2014-06-01

    Model predictions of extinction risks from anthropogenic climate change are dire, but still overly simplistic. To reliably predict at-risk species we need to know which species are currently responding, which are not, and what traits are mediating the responses. For mammals, we have yet to identify overarching physiological, behavioral, or biogeographic traits determining species' responses to climate change, but they must exist. To date, 73 mammal species in North America and eight additional species worldwide have been assessed for responses to climate change, including local extirpations, range contractions and shifts, decreased abundance, phenological shifts, morphological or genetic changes. Only 52% of those species have responded as expected, 7% responded opposite to expectations, and the remaining 41% have not responded. Which mammals are and are not responding to climate change is mediated predominantly by body size and activity times (phylogenetic multivariate logistic regressions, P < 0.0001). Large mammals respond more, for example, an elk is 27 times more likely to respond to climate change than a shrew. Obligate diurnal and nocturnal mammals are more than twice as likely to respond as mammals with flexible activity times (P < 0.0001). Among the other traits examined, species with higher latitudinal and elevational ranges were more likely to respond to climate change in some analyses, whereas hibernation, heterothermy, burrowing, nesting, and study location did not influence responses. These results indicate that some mammal species can behaviorally escape climate change whereas others cannot, analogous to paleontology's climate sheltering hypothesis. Including body size and activity flexibility traits into future extinction risk forecasts should substantially improve their predictive utility for conservation and management.

  5. Model for atomic dielectric response in strong, time-dependent laser fields

    NASA Astrophysics Data System (ADS)

    Rensink, T. C.; Antonsen, T. M.; Palastro, J. P.; Gordon, D. F.

    2014-03-01

    A nonlocal quantum-mechanical model is presented for calculating the atomic dielectric response to a strong laser electric field. By replacing the Coulomb potential with a nonlocal potential in the Schrödinger equation, a 3 + 1-dimensional calculation of the time-dependent electric dipole moment can be reformulated as a 0 + 1-dimensional integral equation that retains the three-dimensional dynamics, while offering significant computational savings. The model is benchmarked against an established ionization model and ab initio simulation of the time-dependent Schrödinger equation. The reduced computational overhead makes the model a promising candidate to incorporate full quantum-mechanical time dynamics in laser pulse propagation simulations.

  6. Early molecular response in chronic myeloid leukemia and halving time: Latest evidences.

    PubMed

    Breccia, Massimo; Molica, Matteo; Colafigli, Gioia; Massaro, Fulvio; Alimena, Giuliana

    2016-09-01

    Achieving a BCR-ABL/ABL ratio <10% at 3 months has become an important goal of treatment for chronic myeloid leukemia (CML) patients treated with tyrosine kinase inhibitors. Several evidences showed that this early molecular response (EMR) is associated with positive long-term outcome in terms of overall survival and progression-free survival, but a consensus has not been reached when this goal is not achieved. European LeukemiaNet recommendations defined patients as treatment failure only after the 6- month time point. Not all patients that lack EMR have similar outcome and it became important to identify patients before this time point of 3 months. Several groups introduced the concept of "halving time" or "velocity of ratio reduction" that could anticipate the possibility to recognize patients deserving a switch to another treatment. Aim of this review is to summarize all evidences reported on the significance of EMR and how this evaluation changed our perspectives and modified our therapeutic strategies.

  7. The time response of glass Resistive Plate Chambers to heavily ionizing particles

    NASA Astrophysics Data System (ADS)

    Artamonov, A.; Blondel, A.; Bogomilov, M.; Booth, C.; Borghi, S.; Catanesi, M. G.; Cervera–Villanueva, A.; Chimenti, P.; Dumarchez, J.; Gastaldi, U.; Giani, S.; Gómez–Cadenas, J. J.; Graulich, J. S.; Grégoire, G.; Grossheim, A.; Guglielmi, A.; Ivanchenko, V.; Kolev, D.; Meurer, C.; Mezzetto, M.; Panman, J.; Piperov, S.; Popov, B.; Radicioni, E.; Schroeter, R.; Temnikov, P.; Tcherniaev, E.; Tsenov, R.; Tsukerman, I.; Wiebusch, C.

    2007-10-01

    The HARP system of resistive plate chambers (RPCs) was designed to perform particle identification by the measurement of the difference in the time-of-flight of different particles. In previous papers an apparent discrepancy was shown between the response of the RPCs to minimum ionizing pions and heavily ionizing protons. Using the kinematics of elastic scattering off a hydrogen target a controlled beam of low momentum recoil protons was directed onto the RPC chambers. With this method the trajectory and momentum, and hence the time-of-flight of the protons can be precisely predicted without need for a measurement of momentum of the protons. It is demonstrated that the measurement of the time-of-arrival of particles by the thin gas-gap glass RPC system of the HARP experiment depends on the primary ionization deposited by the particle in the detector.

  8. Decreased reaction time variability is associated with greater cardiovascular responses to acute stress.

    PubMed

    Wawrzyniak, Andrew J; Hamer, Mark; Steptoe, Andrew; Endrighi, Romano

    2016-05-01

    Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75-min recovery. RT measures were generated from an ex-Gaussian distribution that yielded three predictors: mu-RT, sigma-RT, and tau-RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = -.009, SE = .005, p = .09) and diastolic (B = -.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = -.007, SE = .003, p = .03) and impaired vagal tone (B = -.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses. PMID:26894967

  9. Decreased reaction time variability is associated with greater cardiovascular responses to acute stress

    PubMed Central

    Hamer, Mark; Steptoe, Andrew; Endrighi, Romano

    2016-01-01

    Abstract Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75‐min recovery. RT measures were generated from an ex‐Gaussian distribution that yielded three predictors: mu‐RT, sigma‐RT, and tau‐RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = −.009, SE = .005, p = .09) and diastolic (B = −.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = −.007, SE = .003, p = .03) and impaired vagal tone (B = −.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses. PMID:26894967

  10. Decreased reaction time variability is associated with greater cardiovascular responses to acute stress.

    PubMed

    Wawrzyniak, Andrew J; Hamer, Mark; Steptoe, Andrew; Endrighi, Romano

    2016-05-01

    Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75-min recovery. RT measures were generated from an ex-Gaussian distribution that yielded three predictors: mu-RT, sigma-RT, and tau-RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = -.009, SE = .005, p = .09) and diastolic (B = -.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = -.007, SE = .003, p = .03) and impaired vagal tone (B = -.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses.

  11. Tiger moth responses to a simulated bat attack: timing and duty cycle.

    PubMed

    Barber, J R; Conner, W E

    2006-07-01

    Many night-flying insects perform complex, aerobatic escape maneuvers when echolocating bats initiate attack. Tiger moths couple this kinematic defense with an acoustic reply to a bat's biosonar-guided assault. The jamming hypothesis for the function of these moth sounds assumes that tiger moth clicks presented at high densities, temporally locked to the terminal phase of the bat attack will produce the greatest jamming efficacy. Concomitantly, this hypothesis argues that moths warning bats of bad tasting chemicals sequestered in their tissues should call early to give the bat time to process the meaning of the warning signal and that moths calling at low duty cycles are more likely to employ such an aposematic strategy. We report here the first investigation of a tiger moth assemblage's response to playback of a bat echolocation attack sequence. This assemblage of arctiid moths first answered the echolocation attack sequence 960+/-547 ms (mean +/- s.d.) from the end of the bat attack. The assemblage reached a half-maximum response shortly after the first response, at 763+/-479 ms from the end of the terminal buzz. Tiger moth response reached a maximum at 475+/-344 ms from the end of the sequence; during the approach phase, well before the onset of the terminal buzz. In short, much of tiger moth response to bat attack occurs outside of the jamming hypotheses' predictions. Furthermore, no relationship exists between the duty cycle of a tiger moth's call (and thus the call's probability of jamming the bat) and its temporal response to bat attack. These data call into doubt the assumptions behind the jamming hypothesis as currently stated but do not directly test the functionality of arctiid sounds in disrupting echolocation in bat-moth aerial battles.

  12. The association between affective psychopathic traits, time incarcerated, and cortisol response to psychosocial stress.

    PubMed

    Johnson, Megan M; Mikolajewski, Amy; Shirtcliff, Elizabeth A; Eckel, Lisa A; Taylor, Jeanette

    2015-06-01

    Previous research has demonstrated that psychopathic personality traits are significantly predictive of blunted cortisol reactivity to a performance-based stressor task (Trier Social Stress Test; TSST) in college students. However, the relationship between cortisol reactivity and psychopathy has not been explored in high risk samples such as incarcerated populations. Further, the role of imprisonment in relation to cortisol stress reactivity has not been previously explored, but could have practical and conceptual consequences in regard to rehabilitation and biological sensitivity to context, respectively. The current study tested the hypotheses that both psychopathic personality traits and amount of time incarcerated are related to cortisol blunting in response to stress among incarcerated young adults. A sample of 49 young adult male offenders was recruited to complete the TSST. Salivary hormone samples were taken just prior to and 20 min post-stressor, and participants were interviewed with the Psychopathy Checklist-Youth Version. Variables quantifying the amount of time at the present facility prior to the date of testing and number of commitments in juvenile facilities were also collected. Correlational analyses indicated that only number of incarcerations was related to blunted cortisol. Hierarchical Linear Modeling revealed that time incarcerated and number of commitments were related to a blunted cortisol response among responders and declining cortisol reactivity among nonresponders, respectively. Controlling for time incarcerated, psychopathic traits were significantly related to cortisol decline in response to the stressor among nonresponders, but were not related to blunted cortisol among responders. Results of this project highlight the potential biological effects of prolonged and repeated incarcerations, and extend our understanding about the relationship between psychopathic traits and cortisol reactivity in an incarcerated sample. PMID:25921588

  13. Acceleration of proliferative response of mouse fibroblasts by short-time pretreatment with polyphenols.

    PubMed

    Tsuruya, Makoto; Niwano, Yoshimi; Nakamura, Keisuke; Kanno, Taro; Nakashima, Takuji; Egusa, Hiroshi; Sasaki, Keiichi

    2014-11-01

    Under the hypothesis that photo-irradiated proanthocyanidin could accelerate wound healing through reactive oxygen species (ROS) formation, we examined the effect of proanthocyanidin on 3T3-L1 mouse fibroblasts with or without photo-irradiation. As a result, irrespective of presence or absence of photo-irradiation, only 1 min exposure of the cells to proanthocyanidin resulted in accelerated proliferation of the cells in a concentration-dependent manner. Similarly to proanthocyanidin, 1 min pretreatment with catechin, caffeic acid, and chlorogenic acid accelerated the proliferative response, but gallic acid, epicatechin gallate, epigallocatechin, and epigallocatechin gallate failed. If incorporated active ingredient such as proanthocyanidin for such a short time as 1 min accelerates the proliferation response, a bioassay was conducted by utilizing antioxidant potential of proanthocyanidin. That is, intracellular oxidation of 2',7'-dichlorodihydrofluorescin induced by H2O2 was significantly inhibited when the cells were pretreated with proanthocyanidin for 1 min, suggesting that incorporated proanthocyanidin into the cells exerted antioxidant effect. This was also supported by a liquid chromatography/mass spectrometry analysis in which incorporation of proanthocyanidin components such as catechin monomers and dimers into the cells within 1 min was confirmed. These results suggest that active polyphenolic compounds such as proanthocyanidin, catechin, caffeic acid, and chlorogenic acid incorporated into the cells in such a short time as 1 min could accelerate the proliferative response of the cells. PMID:25173673

  14. Background-free in-vivo Imaging of Vitamin C using Time-gateable Responsive Probe

    PubMed Central

    Song, Bo; Ye, Zhiqing; Yang, Yajie; Ma, Hua; Zheng, Xianlin; Jin, Dayong; Yuan, Jingli

    2015-01-01

    Sensitive optical imaging of active biomolecules in the living organism requires both a molecular probe specifically responsive to the target and a high-contrast approach to remove the background interference from autofluorescence and light scatterings. Here, a responsive probe for ascorbic acid (vitamin C) has been developed by conjugating two nitroxide radicals with a long-lived luminescent europium complex. The nitroxide radical withholds the probe on its “off” state (barely luminescent), until the presence of vitamin C will switch on the probe by forming its hydroxylamine derivative. The probe showed a linear response to vitamin C concentration with a detection limit of 9.1 nM, two orders of magnitude lower than that achieved using electrochemical methods. Time-gated luminescence microscopy (TGLM) method has further enabled real-time, specific and background-free monitoring of cellular uptake or endogenous production of vitamin C, and mapping of vitamin C in living Daphnia magna. This work suggests a rational design of lanthanide complexes for background-free small animal imaging of biologically functional molecules. PMID:26373894

  15. Quadratic response functions in the time-dependent four-component Hartree-Fock approximation

    NASA Astrophysics Data System (ADS)

    Norman, Patrick; Jensen, Hans Jørgen Aa.

    2004-10-01

    The second-order response function has been implemented in the time-dependent four-component Hartree-Fock approximation. The implementation is atomic orbital direct and formulated in terms of Fock-type matrices. It employs a quaternion symmetry scheme that provides maximum computational efficiency with consideration made to time-reversal and spatial symmetries. Calculations are presented for the electric dipole first-order hyperpolarizabilities of CsAg and CsAu in the second-harmonic generation optical process β(-2ω;ω,ω). It is shown that relativistic corrections to property values are substantial in these cases—the orientationally averaged hyperpolarizabilities in the static limit β¯(0;0,0) are overestimated in nonrelativistic calculations by 18% and 66% for CsAg and CsAu, respectively. The dispersion displays anomalies in the band gap region due to one- and two-photon resonances with nonrelativistically spin-forbidden states. Although weakly absorbing these states inflict divergences in the quadratic response function, since the response theoretical approach which is used adopts the infinite excited-state lifetime approximation. This fact calls for caution in applications where knowledge of the exact positioning of all excited states in the spectrum is unknown.

  16. Quadratic response functions in the time-dependent four-component Hartree-Fock approximation.

    PubMed

    Norman, Patrick; Jensen, Hans Jørgen Aa

    2004-10-01

    The second-order response function has been implemented in the time-dependent four-component Hartree-Fock approximation. The implementation is atomic orbital direct and formulated in terms of Fock-type matrices. It employs a quaternion symmetry scheme that provides maximum computational efficiency with consideration made to time-reversal and spatial symmetries. Calculations are presented for the electric dipole first-order hyperpolarizabilities of CsAg and CsAu in the second-harmonic generation optical process beta(-2omega;omega,omega). It is shown that relativistic corrections to property values are substantial in these cases--the orientationally averaged hyperpolarizabilities in the static limit beta(0;0,0) are overestimated in nonrelativistic calculations by 18% and 66% for CsAg and CsAu, respectively. The dispersion displays anomalies in the band gap region due to one- and two-photon resonances with nonrelativistically spin-forbidden states. Although weakly absorbing these states inflict divergences in the quadratic response function, since the response theoretical approach which is used adopts the infinite excited-state lifetime approximation. This fact calls for caution in applications where knowledge of the exact positioning of all excited states in the spectrum is unknown. PMID:15446908

  17. Developing Human Resources through Actualizing Human Potential

    ERIC Educational Resources Information Center

    Clarken, Rodney H.

    2012-01-01

    The key to human resource development is in actualizing individual and collective thinking, feeling and choosing potentials related to our minds, hearts and wills respectively. These capacities and faculties must be balanced and regulated according to the standards of truth, love and justice for individual, community and institutional development,…

  18. [Actual diet of patients with gastrointestinal diseases].

    PubMed

    Loranskaia, T I; Shakhovskaia, A K; Pavliuchkova, M S

    2000-01-01

    The study of actual nutrition of patients with erosive-ulcerative lesions in the gastroduodenal zone and of patients with operated ulcer has revealed defects in intake of essential nutrients by these patients: overeating of animal fat and refined carbohydrates, deficiency of oil, vitamins A, B2, C, D and food fibers.

  19. Humanistic Education and Self-Actualization Theory.

    ERIC Educational Resources Information Center

    Farmer, Rod

    1984-01-01

    Stresses the need for theoretical justification for the development of humanistic education programs in today's schools. Explores Abraham Maslow's hierarchy of needs and theory of self-actualization. Argues that Maslow's theory may be the best available for educators concerned with educating the whole child. (JHZ)

  20. Group Counseling for Self-Actualization.

    ERIC Educational Resources Information Center

    Streich, William H.; Keeler, Douglas J.

    Self-concept, creativity, growth orientation, an integrated value system, and receptiveness to new experiences are considered to be crucial variables to the self-actualization process. A regular, year-long group counseling program was conducted with 85 randomly selected gifted secondary students in the Farmington, Connecticut Public Schools. A…

  1. Timing and cue competition in conditioning of the nictitating membrane response of the rabbit (Oryctolagus cuniculus).

    PubMed

    Kehoe, E James; Ludvig, Elliot A; Sutton, Richard S

    2013-01-01

    Rabbits were classically conditioned using compounds of tone and light conditioned stimuli (CSs) presented with either simultaneous onsets (Experiment 1) or serial onsets (Experiment 2) in a delay conditioning paradigm. Training with the simultaneous compound reduced the likelihood of a conditioned response (CR) to the individual CSs ("mutual overshadowing") but left CR timing unaltered. CR peaks were consistently clustered around the time of unconditioned stimulus (US) delivery. Training with the serial compound (CSA→CSB→US) reduced responding to CSB ("temporal primacy/information effect") but this effect was prevented by prior CSB→US pairings. In both cases, serial compound training altered CR timing. On CSA→CSB test trials, the CRs were accelerated; the CR peaks occurred after CSB onset but well before the time of US delivery. Conversely, CRs on CSB- trials were decelerated; the distribution of CR peaks was variable but centered well after the US. Timing on CSB- trials was at most only slightly accelerated. The results are discussed with respect to processes of generalization and spectral timing applicable to the cerebellar and forebrain pathways in eyeblink preparations.

  2. Spatial heterogeneity in the timing of birch budburst in response to future climate warming in Ireland.

    PubMed

    Caffarra, Amelia; Zottele, Fabio; Gleeson, Emily; Donnelly, Alison

    2014-05-01

    In order to predict the impact of future climate warming on trees it is important to quantify the effect climate has on their development. Our understanding of the phenological response to environmental drivers has given rise to various mathematical models of the annual growth cycle of plants. These models simulate the timing of phenophases by quantifying the relationship between development and its triggers, typically temperature. In addition, other environmental variables have an important role in determining the timing of budburst. For example, photoperiod has been shown to have a strong influence on phenological events of a number of tree species, including Betula pubescens (birch). A recently developed model for birch (DORMPHOT), which integrates the effects of temperature and photoperiod on budburst, was applied to future temperature projections from a 19-member ensemble of regional climate simulations (on a 25 km grid) generated as part of the ENSEMBLES project, to simulate the timing of birch budburst in Ireland each year up to the end of the present century. Gridded temperature time series data from the climate simulations were used as input to the DORMPHOT model to simulate future budburst timing. The results showed an advancing trend in the timing of birch budburst over most regions in Ireland up to 2100. Interestingly, this trend appeared greater in the northeast of the country than in the southwest, where budburst is currently relatively early. These results could have implications for future forest planning, species distribution modeling, and the birch allergy season. PMID:24037345

  3. Spatial heterogeneity in the timing of birch budburst in response to future climate warming in Ireland.

    PubMed

    Caffarra, Amelia; Zottele, Fabio; Gleeson, Emily; Donnelly, Alison

    2014-05-01

    In order to predict the impact of future climate warming on trees it is important to quantify the effect climate has on their development. Our understanding of the phenological response to environmental drivers has given rise to various mathematical models of the annual growth cycle of plants. These models simulate the timing of phenophases by quantifying the relationship between development and its triggers, typically temperature. In addition, other environmental variables have an important role in determining the timing of budburst. For example, photoperiod has been shown to have a strong influence on phenological events of a number of tree species, including Betula pubescens (birch). A recently developed model for birch (DORMPHOT), which integrates the effects of temperature and photoperiod on budburst, was applied to future temperature projections from a 19-member ensemble of regional climate simulations (on a 25 km grid) generated as part of the ENSEMBLES project, to simulate the timing of birch budburst in Ireland each year up to the end of the present century. Gridded temperature time series data from the climate simulations were used as input to the DORMPHOT model to simulate future budburst timing. The results showed an advancing trend in the timing of birch budburst over most regions in Ireland up to 2100. Interestingly, this trend appeared greater in the northeast of the country than in the southwest, where budburst is currently relatively early. These results could have implications for future forest planning, species distribution modeling, and the birch allergy season.

  4. Spatial heterogeneity in the timing of birch budburst in response to future climate warming in Ireland

    NASA Astrophysics Data System (ADS)

    Caffarra, Amelia; Zottele, Fabio; Gleeson, Emily; Donnelly, Alison

    2014-05-01

    In order to predict the impact of future climate warming on trees it is important to quantify the effect climate has on their development. Our understanding of the phenological response to environmental drivers has given rise to various mathematical models of the annual growth cycle of plants. These models simulate the timing of phenophases by quantifying the relationship between development and its triggers, typically temperature. In addition, other environmental variables have an important role in determining the timing of budburst. For example, photoperiod has been shown to have a strong influence on phenological events of a number of tree species, including Betula pubescens (birch). A recently developed model for birch (DORMPHOT), which integrates the effects of temperature and photoperiod on budburst, was applied to future temperature projections from a 19-member ensemble of regional climate simulations (on a 25 km grid) generated as part of the ENSEMBLES project, to simulate the timing of birch budburst in Ireland each year up to the end of the present century. Gridded temperature time series data from the climate simulations were used as input to the DORMPHOT model to simulate future budburst timing. The results showed an advancing trend in the timing of birch budburst over most regions in Ireland up to 2100. Interestingly, this trend appeared greater in the northeast of the country than in the southwest, where budburst is currently relatively early. These results could have implications for future forest planning, species distribution modeling, and the birch allergy season.

  5. Field Experience with and Potential for Multi-time Scale Grid Transactions from Responsive Commercial Buildings

    SciTech Connect

    Piette, Mary Ann; Kiliccote, Sila; Ghatikar, Girish

    2014-08-01

    The need for and concepts behind demand response are evolving. As the electric system changes with more intermittent renewable electric supply systems, there is a need to allow buildings to provide more flexible demand. This paper presents results from field studies and pilots, as well as engineering estimates of the potential capabilities of fast load responsiveness in commercial buildings. We present a sector wide analysis of flexible loads in commercial buildings, which was conducted to improve resource planning and determine which loads to evaluate in future demonstrations. These systems provide important capabilities for future transactional systems. The field analysis is based on results from California, plus projects in the northwest and east coast. End-uses considered include heating, ventilation, air conditioning and lighting. The timescales of control include day-ahead, as well as day-of, 10-minute ahead and even faster response. This technology can provide DR signals on different times scales to interact with responsive building loads. We describe the latency of the control systems in the building and the round trip communications with the wholesale grid operators.

  6. Dose-Dependent Effects of Androgens on the Circadian Timing System and Its Response to Light

    PubMed Central

    Butler, Matthew P.; Karatsoreos, Ilia N.; LeSauter, Joseph

    2012-01-01

    The hypothalamic suprachiasmatic nucleus (SCN) is the locus of a master clock that regulates circadian rhythms in physiology and behavior. Gonadectomy in male mice lengthens the period of circadian rhythms and increases the day-to-day variability of activity onset time. Both of these responses are rescued by the nonaromatizable androgen dihydrotestosterone. Androgen receptors (AR) are localized in SCN neurons that receive direct retinal input. To explore how androgens affect circadian clock function and its responsiveness to photic cues, we measured wheel-running behavior and SCN AR expression in intact, gonadectomized, and testosterone-replaced mice, held under various photic conditions. Gonadectomy lengthened circadian period in constant dim light but not in constant darkness. Increasing intensities of constant light parametrically increased circadian period, and this was potentiated at all intensities by gonadectomy. In contrast, gonadectomy did not alter light-induced pupil constriction, suggesting a nonretinal locus of hormone action. In hormone-replaced animals housed in constant darkness, T concentration was positively correlated with precision of activity onset and with SCN AR expression and negatively correlated with duration of activity. We infer the existence of two androgenic mechanisms: one modulates SCN responsiveness to light, and the second modulates SCN timekeeping and locomotor activity in a dose-dependent manner. Finally, the effects of androgens on period are a result of hormonal modulation of the SCN's response to photic input rather than to a change in the inherent period of oscillators in the absence of light. PMID:22492303

  7. The response of the TIMED/SABER O2 nightglow to solar radiation

    NASA Astrophysics Data System (ADS)

    Gao, Hong; Xu, Jiyao; William, Ward

    2015-04-01

    The TIMED/SABER O2 nightglow observations between January 2002 and June 2014 are used to study the response of O2 emission to the solar radiation. both the O2 nightglow emission rate and intensity are found to be positively correlated to the solar radiation. The O2 nightglow emission rate/intensity and F10.7 solar flux index can be expressed by a linear relation very well. The response of the O2 global mean nightglow emission rate to the solar radiation is enhanced with increasing altitude from about 80km, reaches its peak around 92 km and then decreases with increasing altitude. The response of the O2 nightglow intensity to F10.7 index changes with latitude with three peaks around 40S/N and the equator. The response of the O2 global mean nightglow intensity to the solar radiation is about 27 kR/100 sfu, corresponding to 24.1%/100 sfu.

  8. Response Times to Gustatory–Olfactory Flavor Mixtures: Role of Congruence

    PubMed Central

    Shepard, Timothy G.; Veldhuizen, Maria G.

    2015-01-01

    A mixture of perceptually congruent gustatory and olfactory flavorants (sucrose and citral) was previously shown to be detected faster than predicted by a model of probability summation that assumes stochastically independent processing of the individual gustatory and olfactory signals. This outcome suggests substantial integration of the signals. Does substantial integration also characterize responses to mixtures of incongruent flavorants? Here, we report simple response times (RTs) to detect brief pulses of 3 possible flavorants: monosodium glutamate, MSG (gustatory: “umami” quality), citral (olfactory: citrus quality), and a mixture of MSG and citral (gustatory–olfactory). Each stimulus (and, on a fraction of trials, water) was presented orally through a computer-operated, automated flow system, and subjects were instructed to press a button as soon as they detected any of the 3 non-water stimuli. Unlike responses previously found to the congruent mixture of sucrose and citral, responses here to the incongruent mixture of MSG and citral took significantly longer (RTs were greater) and showed lower detection rates than the values predicted by probability summation. This outcome suggests that the integration of gustatory and olfactory flavor signals is less extensive when the component flavors are perceptually incongruent rather than congruent, perhaps because incongruent flavors are less familiar. PMID:26304508

  9. Response Times to Gustatory-Olfactory Flavor Mixtures: Role of Congruence.

    PubMed

    Shepard, Timothy G; Veldhuizen, Maria G; Marks, Lawrence E

    2015-10-01

    A mixture of perceptually congruent gustatory and olfactory flavorants (sucrose and citral) was previously shown to be detected faster than predicted by a model of probability summation that assumes stochastically independent processing of the individual gustatory and olfactory signals. This outcome suggests substantial integration of the signals. Does substantial integration also characterize responses to mixtures of incongruent flavorants? Here, we report simple response times (RTs) to detect brief pulses of 3 possible flavorants: monosodium glutamate, MSG (gustatory: "umami" quality), citral (olfactory: citrus quality), and a mixture of MSG and citral (gustatory-olfactory). Each stimulus (and, on a fraction of trials, water) was presented orally through a computer-operated, automated flow system, and subjects were instructed to press a button as soon as they detected any of the 3 non-water stimuli. Unlike responses previously found to the congruent mixture of sucrose and citral, responses here to the incongruent mixture of MSG and citral took significantly longer (RTs were greater) and showed lower detection rates than the values predicted by probability summation. This outcome suggests that the integration of gustatory and olfactory flavor signals is less extensive when the component flavors are perceptually incongruent rather than congruent, perhaps because incongruent flavors are less familiar.

  10. Time-domain sampling of x-ray pulses using an ultrafast sample response

    SciTech Connect

    Gaal, P.; Shayduk, R.; Schick, D.; Herzog, M.; Bojahr, A.; Goldshteyn, J.; Navirian, H. A.; Leitenberger, W.; Vrejoiu, I.; Khakhulin, D.; Wulff, M.; Bargheer, M.

    2012-12-10

    We employ the ultrafast response of a 15.4 nm thin SrRuO{sub 3} layer grown epitaxially on a SrTiO{sub 3} substrate to perform time-domain sampling of an x-ray pulse emitted from a synchrotron storage ring. Excitation of the sample with an ultrashort laser pulse triggers coherent expansion and compression waves in the thin layer, which turn the diffraction efficiency on and off at a fixed Bragg angle during 5 ps. This is significantly shorter than the duration of the synchrotron x-ray pulse of 100 ps. Cross-correlation measurements of the ultrafast sample response and the synchrotron x-ray pulse allow to reconstruct the x-ray pulse shape.

  11. Detecting lies about consumer attitudes using the timed antagonistic response alethiometer.

    PubMed

    Gregg, Aiden P; Mahadevan, Nikhila; Edwards, Sonja E; Klymowsky, James

    2014-09-01

    The Timed Antagonistic Response Alethiometer (TARA) is a true-false statement classification task that diagnoses lying on the basis of slower average response speeds. Previous research (Gregg in Applied Cognitive Psychology, 21, 621-647, 2007) showed that a computer-based TARA was about 80 % accurate when its statements conveyed demographic facts or religious views. Here, we tested the TARA's diagnostic potential when its statements conveyed attitudes-here, toward both branded and generic consumer products-across different versions of the TARA (Exps. 1a, 1b, and 1c), as well as across consecutive administrations (Exp. 2). The results generalized well across versions, and maximal accuracy rates exceeding 80 % were obtained, although accuracy declined somewhat upon readministration. Overall, the TARA shows promise as a comparatively cheap, convenient, and diagnostic index of lying about attitudes. PMID:24166022

  12. A novel WV film for fast-response-time OCB-LCD

    NASA Astrophysics Data System (ADS)

    Matsubara, Ryota; Ito, Yoji; Nakamura, Shun; Mori, Hiroyuki; Mihayashi, Keiji

    2006-02-01

    We have successfully developed and commercialized an optical compensation film for OCB-LCD mode (OCB-WV film). OCB-LCD mode is known to have a very fast optical response time and makes next-generation fast-response LCD-TVs possible and free from image blurring. The OCB-WV film, which has a structure composed with TAC (triacetyl cellulose) film and PDM (polymerized discotic material) layer, can realize the wide viewing angle of OCB-cell. In order to provide the best performance of OCB-cell, we optimized an optical parameter of not only WV film but also OCB cell by a numerical simulation. In this paper, we will discuss a concept of its optimization, which provide excellent results of a numerical simulation.

  13. Time dependent response of equatorial ionospheric electric fields to magnetospheric disturbances

    SciTech Connect

    Fejer, B.G.; Scherliess, L.

    1995-04-01

    The authors use extensive radar measurements of F region vertical plasma drifts and auroral electrojet indices to determine the storm time dependence of equatorial zonal electric fields. These disturbance drifts result from the prompt penetration of high latitude electric fields and from the dynamo action of storm time winds which produce the largest perturbations a few hours after the onset of magnetic activity. The signatures of the equatorial disturbance electric fields change significantly depending on the relative contributions of these two components. The prompt electric field responses, with lifetimes of about one hour, are in excellent agreement with results from global convection models. The electric fields generated by storm time winds have longer lifetimes, amplitudes proportional to the energy input into the high latitude ionosphere, and a daily variation which follows closely the disturbance dynamo pattern of Blanc and Richmond. The storm wind driven electric fields are responsible for the larger amplitudes and longer lifetimes of the drift perturbations following sudden decreases in convection compared to those associated with sudden convection enhancements. 14 refs., 6 figs., 1 tab.

  14. Reduction of electron density in the night-time lower ionosphere in response to a thunderstorm

    NASA Astrophysics Data System (ADS)

    Shao, Xuan-Min; Lay, Erin H.; Jacobson, Abram R.

    2013-01-01

    Tropospheric thunderstorms have been reported to disturb the lower ionosphere, at altitudes of 65-90km, by convective atmospheric gravity waves and by electric field changes produced by lightning discharges. Theoretical simulations suggest that lightning electric fields enhance electron attachment to O2 and reduce electron density in the lower ionosphere. Owing to the low electron density in the lower ionosphere, active probing of its electron distribution is difficult, and the various perturbative effects are poorly understood. However, it is now possible to probe the lower ionosphere in a spatially and temporally resolved manner by using remotely detected time waveforms of lightning radio signals. Here we report such observations of the night-time ionosphere above a small thunderstorm. We find that electron density in the lower ionosphere decreased in response to lightning discharges. The extent of the reduction is closely related in time and space to the rate of lightning discharges, supporting the idea that the enhanced electron attachment is responsible for the reduction. We conclude that ionospheric electron density variations corresponding to lightning discharges should be considered in future simulations of the ionosphere and the initiation of sprite discharges.

  15. Development of a micro cell compression stimulator for evaluating real-time cellular responses

    NASA Astrophysics Data System (ADS)

    Nakashima, Y.; Yang, Y.; Minami, K.

    2012-05-01

    This paper presents a micro cell compression stimulator for evaluating real-time cellular responses to compression stimuli. The device was produced by a micro three-dimensional structure fabrication process using multiple exposures to the photoresist. The device consists of a pressure inlet port, cell inlet ports, a gasket, microchannels, cell culture chambers, and a diaphragm on the culture chamber for applying compressive pressure to cells. Compression stimuli applied to the cells can be controlled by regulating the expansion of the diaphragm via a pressure control. The device permits the observation of cellular responses to compressive pressure in real time because it is made of transparent materials and stimulates the cells without deforming the cell culture surface, when observed by optical microscopy. We demonstrated the validity of the fabrication process, evaluated the performance of the fabricated device, and compared the experimental results with the FEM structural analysis results. We found through operational testing that the diaphragm was deformed quickly by applying negative/positive pressure and that the diaphragm displacement became larger with increasing applied pressure. These results indicate that this device can be used to control the intensity and the cell stimulus profile by regulating the applied pressure. In all cases, the cellular deformation during compression stimulus was successfully observed in real time using an optical microscope. The device is expected to facilitate the control of stem cell differentiation and the clarification of cellular mechanoreceptor mechanisms and signal transduction pathways.

  16. Real-time, whole-brain, temporally resolved pressure responses in translational head impact.

    PubMed

    Zhao, Wei; Ji, Songbai

    2016-02-01

    Theoretical debate still exists on the role of linear acceleration ( a lin) on the risk of brain injury. Recent injury metrics only consider head rotational acceleration ( a rot) but not a lin, despite that real-world on-field head impacts suggesting a lin significantly improves a concussion risk function. These controversial findings suggest a practical challenge in integrating theory and real-world experiment. Focusing on tissue-level mechanical responses estimated from finite-element (FE) models of the human head, rather than impact kinematics alone, may help address this debate. However, the substantial computational cost incurred (runtime and hardware) poses a significant barrier for their practical use. In this study, we established a real-time technique to estimate whole-brain a lin-induced pressures. Three hydrostatic atlas pressures corresponding to translational impacts (referred to as 'brain print') along the three major axes were pre-computed. For an arbitrary a lin profile at any instance in time, the atlas pressures were linearly scaled and then superimposed to estimate whole-brain responses. Using 12 publically available, independently measured or reconstructed real-world a lin profiles representative of a range of impact/injury scenarios, the technique was successfully validated (except for one case with an extremely short impulse of approx. 1 ms). The computational cost to estimate whole-brain pressure responses for an entire a lin profile was less than 0.1 s on a laptop versus typically hours on a high-end multicore computer. These findings suggest the potential of the simple, yet effective technique to enable future studies to focus on tissue-level brain responses, rather than solely relying on global head impact kinematics that have plagued early and contemporary brain injury research to date.

  17. Time-Critical Studies: Rapid response to Transient Dynamic Mid-Ocean Ridge Events

    NASA Astrophysics Data System (ADS)

    Cowen, J. P.; Baker, E. T.; Dziak, R. P.; Lilley, M. M.

    2003-12-01

    The Time-Critical Studies (TCS) Theme of Ridge 2000 focuses on observations of the immediate geochemical and geobiological consequences of magmatic and tectonic events along the global mid-ocean ridge system. To date funding has centered on the Juan de Fuca and Gorda Ridges which are within the range of the U.S. Navy's Northeast Pacific Sound Surveillance System (SOSUS). NOAA's T-Phase Monitoring Program has accessed SOSUS in real-time since 1993, providing the TCS community with detection of seismicity associated with eruptive or tectonic activity along these two ridges. This remote detection of earthquake swarms along the N.E. Pacific mid-ocean ridge coupled to NSF funding for pre-event staging equipment and supplies has allowed directed and increasingly well-organized field responses to the event site. Major rapid and follow-up response cruises have been successfully mounted to 1993 CoAxial, 1996 and 2001 Gorda Ridge, the 1998 Axial Volcano, and 2001 Middle Valley magmatic episodes. The logistical approach required to study these events has been greatly facilitated by the RIDGE/Ridge 2000 programs and collaboration between university, NOAA and Canadian investigators. Not only have our studies of these events significantly impacted our ideas on the nature of crustal accretion, but they also have led to the discovery and preliminary documentation of a previously unrecognized biomass reservoir that lives below the seafloor and is swept out during these cataclysmic events, and to increased appreciation of the formation and thermal, chemical and biogeochemical implications of the 'Event Plumes' commonly associated with sea floor magmatic events. Rapid shore-to-event site response is an important aspect of TCS. Proposals to enhance the event detection and response effort are welcome at any Ridge 2000 target date. The Ridge 2000 program recognizes that even the most rapid ship response will miss the earliest subsurface and water column expressions of magmatic events

  18. Real-time photoacoustic imaging of rat deep brain: hemodynamic responses to hypoxia

    NASA Astrophysics Data System (ADS)

    Kawauchi, Satoko; Iwazaki, Hideaki; Ida, Taiichiro; Hosaka, Tomoya; Kawaguchi, Yasushi; Nawashiro, Hiroshi; Sato, Shunichi

    2013-03-01

    Hemodynamic responses of the brain to hypoxia or ischemia are one of the major interests in neurosurgery and neuroscience. In this study, we performed real-time transcutaneous PA imaging of the rat brain that was exposed to a hypoxic stress and investigated depth-resolved responses of the brain, including the hippocampus. A linear-array 8ch 10-MHz ultrasonic sensor (measurement length, 10 mm) was placed on the shaved scalp. Nanosecond, 570-nm and 595- nm light pulses were used to excite PA signals indicating cerebral blood volume (CBV) and blood deoxygenation, respectively. Under spontaneous respiration, inhalation gas was switched from air to nitrogen, and then reswitched to oxygen, during which real-time PA imaging was performed continuously. High-contrast PA signals were observed from the depth regions corresponding to the scalp, skull, cortex and hippocampus. After starting hypoxia, PA signals at 595 nm increased immediately in both the cortex and hippocampus for about 1.5 min, showing hemoglobin deoxygenation. On the other hand, PA signals at 570 nm coming from these regions did not increase in the early phase but started to increase at about 1.5 min after starting hypoxia, indicating reactive hyperemia to hypoxia. During hypoxia, PA signals coming from the scalp decreased transiently, which is presumably due to compensatory response in the peripheral tissue to preserve blood perfusion in the brain. The reoxygenation caused a gradual recovery of these PA signals. These findings demonstrate the usefulness of PA imaging for real-time, depth-resolved observation of cerebral hemodynamics.

  19. Cumulative Instructional Time and Relative Effectiveness Conclusions: Extending Research on Response Intervals, Learning, and Measurement Scale.

    PubMed

    Black, Michelle P; Skinner, Christopher H; Forbes, Bethany E; McCurdy, Merilee; Coleman, Mari Beth; Davis, Kristie; Gettelfinger, Maripat

    2016-03-01

    Adapted alternating treatments designs were used to evaluate three computer-based flashcard reading interventions (1-s, 3-s, or 5-s response intervals) across two students with disabilities. When learning was plotted with cumulative instructional sessions on the horizontal axis, the session-series graphs suggest that the interventions were similarly effective. When the same data were plotted as a function of cumulative instructional seconds, time-series graphs suggest that the 1-s intervention caused the most rapid learning for one student. Discussion focuses on applied implications of comparative effectiveness studies and why measures of cumulative instructional time are needed to identify the most effective intervention(s).Comparative effectiveness studies may not identify the intervention which causes the most rapid learning.Session-series repeated measures are not the same as time-series repeated measures.Measuring the time students spend in each intervention (i.e., cumulative instructional seconds) allows practitioners to identify interventions that enhance learning most rapidly.Student time spent working under interventions is critical for drawing applied conclusions. PMID:27606240

  20. Characteristics and control response of the TOPAZ II Reactor System Real-time Dynamic Simulator

    SciTech Connect

    Kwok, K.S.

    1993-11-12

    A dynamic simulator of the TOPAZ II reactor system has been developed for the Nuclear Electric Propulsion Space Test Program. The simulator combines first-principle modeling and empirical correlations in its algorithm to attain the modeling accuracy and computational through-put that are required for real-time execution. The overall execution time of the simulator for each time step is 15 ms when no data is written to the disk, and 18 ms when nine double precision data points are written to the disk once in every time step. The simulation program has been tested and it is able to handle a step decrease of $8 worth of reactivity. It also provides simulations of fuel, emitter, collector, stainless steel, and ZrH moderator failures. Presented in this paper are the models used in the calculations, a sample simulation session, and a discussion of the performance and limitations of the simulator. The simulator has been found to provide realistic real-time dynamic response of the TOPAZ II reactor system under both normal and casualty conditions.

  1. Visual analytics of phosphorylation time-series data on insulin response

    NASA Astrophysics Data System (ADS)

    Ma, David K. G.; Stolte, Christian; Kaur, Sandeep; Bain, Michael; O'Donoghue, Seán I.

    2013-10-01

    Visual analysis of time-series data on protein phosphorylation presents a particular challenge: bioinformatics tools currently available for visualising 'omics' data in time series have been developed primarily to study gene expression, and cannot easily be adopted to phosphorylation data, where a single protein typically has multiple phosphosites. In this study, we worked with an experimental research group that is applying very recent methods in high-throughput experimental proteomics to study the time course of protein phosphorylation events in human cells in vitro following stimulation by insulin, as part of a broader study of diabetes and obesity. We applied several existing visual analytics approaches with the goal of organising the data to facilitate new insight into underlying molecular processes. We developed a novel layout strategy called 'Minardo' that is loosely based on cell topology and ordered by time and causality. This layout utilises a frame of reference familiar to life scientists and helpful for organising and interpreting time-series data. This strategy proved to be useful, leading to new insights into the insulin response pathway. We are working on generalising the Minardo layout to accommodate similar datasets related to other signalling pathways, which should be straightforward.

  2. Solvent effects in time-dependent self-consistent field methods. I. Optical response calculations.

    PubMed

    Bjorgaard, J A; Kuzmenko, V; Velizhanin, K A; Tretiak, S

    2015-01-28

    We implement and examine three excited state solvent models in time-dependent self-consistent field methods using a consistent formalism which unambiguously shows their relationship. These are the linear response, state specific, and vertical excitation solvent models. Their effects on energies calculated with the equivalent of COSMO/CIS/AM1 are given for a set of test molecules with varying excited state charge transfer character. The resulting solvent effects are explained qualitatively using a dipole approximation. It is shown that the fundamental differences between these solvent models are reflected by the character of the calculated excitations. PMID:25637965

  3. A mercury flow meter for ion thruster testing. [response time, thermal sensitivity

    NASA Technical Reports Server (NTRS)

    Wilbur, P. J.

    1973-01-01

    The theory of operation of the thermal flow meter is presented, and a theoretical model is used to determine design parameters for a device capable of measuring mercury flows in the range of 0 to 5 gm/hr. Flow meter construction is described. Tests performed using a positive displacement mercury pump as well as those performed with the device in the feed line of an operating thruster are discussed. A flow meter response time of about a minute and a sensitivity of about 10 mv/gm/hr are demonstrated. Additional work to relieve a sensitivity of the device to variations in ambient temperature is indicated to improve its quantitative performance.

  4. Solvent effects in time-dependent self-consistent field methods. I. Optical response calculations

    SciTech Connect

    Bjorgaard, J. A.; Kuzmenko, V.; Velizhanin, K. A.; Tretiak, S.

    2015-01-22

    In this study, we implement and examine three excited state solvent models in time-dependent self-consistent field methods using a consistent formalism which unambiguously shows their relationship. These are the linear response, state specific, and vertical excitation solvent models. Their effects on energies calculated with the equivalent of COSMO/CIS/AM1 are given for a set of test molecules with varying excited state charge transfer character. The resulting solvent effects are explained qualitatively using a dipole approximation. It is shown that the fundamental differences between these solvent models are reflected by the character of the calculated excitations.

  5. Visual response time to colored stimuli in peripheral retina - Evidence for binocular summation

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1977-01-01

    Simple onset response time (RT) experiments, previously shown to exhibit binocular summation effects for white stimuli along the horizontal meridian, were performed for red and green stimuli along 5 oblique meridians. Binocular RT was significantly shorter than monocular RT for a 45-min-diameter spot of red, green, or white light within eccentricities of about 50 deg from the fovea. Relatively large meridian differences were noted that appear to be due to the degree to which the images fall on corresponding retinal areas.

  6. Electronic excitation spectra from time-dependent density functional response theory using plane-wave methods

    NASA Astrophysics Data System (ADS)

    Doltsinis, Nikos L.; Sprik, Michiel

    2000-11-01

    The time-dependent density functional response theory method for the computation of electronic excitation spectra has been implemented in a plane-wave basis set/pseudo-potential formalism. We compare our test results for N2 and H2CO to literature atomic basis set calculations and find good agreement. We also discuss some of the technical complications specific to the use of plane-wave basis sets. As an application, the thermally broadened photoabsorption spectrum of formamide at room temperature is computed by averaging over a number of vibrational configurations sampled from an ab initio molecular dynamics run and compared to experiment.

  7. FIXED-TIME SCHEDULE EFFECTS IN COMBINATION WITH RESPONSE-DEPENDENT SCHEDULES

    PubMed Central

    Borrero, John C; Bartels-Meints, Jamie A; Sy, Jolene R; Francisco, Monica T

    2011-01-01

    We evaluated the effects of fixed-interval (FI), fixed-time (FT), and conjoint (combined) FI FT reinforcement schedules on the responding of 3 adults who had been diagnosed with schizophrenia. Responding on vocational tasks decreased for 2 of 3 participants under FT alone relative to FI alone. Responding under FI FT resulted in response persistence for 2 of 3 participants. Results have implications for the maintenance of desirable behavior, as well as for situations in which FT treatment has been implemented for problem behavior and problem behavior is nevertheless reinforced by caregivers. PMID:21541131

  8. Real-time performance modelling of a Sustained Attention to Response Task.

    PubMed

    Larue, Grégoire S; Rakotonirainy, Andry; Pettitt, Anthony N

    2010-10-01

    Vigilance declines when exposed to highly predictable and uneventful tasks. Monotonous tasks provide little cognitive and motor stimulation and contribute to human errors. This paper aims to model and detect vigilance decline in real time through participants' reaction times during a monotonous task. A laboratory-based experiment adapting the Sustained Attention to Response Task (SART) is conducted to quantify the effect of monotony on overall performance. Relevant parameters are then used to build a model detecting hypovigilance throughout the experiment. The accuracy of different mathematical models is compared to detect in real time - minute by minute - the lapses in vigilance during the task. It is shown that monotonous tasks can lead to an average decline in performance of 45%. Furthermore, vigilance modelling enables the detection of vigilance decline through reaction times with an accuracy of 72% and a 29% false alarm rate. Bayesian models are identified as a better model to detect lapses in vigilance as compared with neural networks and generalised linear mixed models. This modelling could be used as a framework to detect vigilance decline of any human performing monotonous tasks. STATEMENT OF RELEVANCE: Existing research on monotony is largely entangled with endogenous factors such as sleep deprivation, fatigue and circadian rhythm. This paper uses a Bayesian model to assess the effects of a monotonous task on vigilance in real time. It is shown that the negative effects of monotony on the ability to sustain attention can be mathematically modelled and predicted in real time using surrogate measures, such as reaction times. This allows the modelling of vigilance fluctuations.

  9. Real-time performance modelling of a Sustained Attention to Response Task.

    PubMed

    Larue, Grégoire S; Rakotonirainy, Andry; Pettitt, Anthony N

    2010-10-01

    Vigilance declines when exposed to highly predictable and uneventful tasks. Monotonous tasks provide little cognitive and motor stimulation and contribute to human errors. This paper aims to model and detect vigilance decline in real time through participants' reaction times during a monotonous task. A laboratory-based experiment adapting the Sustained Attention to Response Task (SART) is conducted to quantify the effect of monotony on overall performance. Relevant parameters are then used to build a model detecting hypovigilance throughout the experiment. The accuracy of different mathematical models is compared to detect in real time - minute by minute - the lapses in vigilance during the task. It is shown that monotonous tasks can lead to an average decline in performance of 45%. Furthermore, vigilance modelling enables the detection of vigilance decline through reaction times with an accuracy of 72% and a 29% false alarm rate. Bayesian models are identified as a better model to detect lapses in vigilance as compared with neural networks and generalised linear mixed models. This modelling could be used as a framework to detect vigilance decline of any human performing monotonous tasks. STATEMENT OF RELEVANCE: Existing research on monotony is largely entangled with endogenous factors such as sleep deprivation, fatigue and circadian rhythm. This paper uses a Bayesian model to assess the effects of a monotonous task on vigilance in real time. It is shown that the negative effects of monotony on the ability to sustain attention can be mathematically modelled and predicted in real time using surrogate measures, such as reaction times. This allows the modelling of vigilance fluctuations. PMID:20865604

  10. Nonlinear optical response induced by non-Abelian Berry curvature in time-reversal-invariant insulators

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Liu, Ren-Bao

    2014-12-01

    We propose a general framework of nonlinear optics induced by non-Abelian Berry curvature in time-reversal-invariant (TRI) insulators. We find that the third-order response of a TRI insulator under optical and terahertz light fields is directly related to the integration of the non-Abelian Berry curvature over the Brillouin zone. We apply the result to insulators with rotational symmetry near the band edge. Under resonant excitations, the optical susceptibility is proportional to the flux of the Berry curvature through the iso-energy surface, which is equal to the Chern number of the surface times 2 π . For the III-V compound semiconductors, microscopic calculations based on the six-band model give a third-order susceptibility with the Chern number of the iso-energy surface equal to 3.

  11. A cross-language study of compensation in response to real-time formant perturbation

    PubMed Central

    Mitsuya, Takashi; MacDonald, Ewen N.; Purcell, David W.; Munhall, Kevin G.

    2011-01-01

    Past studies have shown that when formants are perturbed in real time, speakers spontaneously compensate for the perturbation by changing their formant frequencies in the opposite direction to the perturbation. Further, the pattern of these results suggests that the processing of auditory feedback error operates at a purely acoustic level. This hypothesis was tested by comparing the response of three language groups to real-time formant perturbations, (1) native English speakers producing an English vowel /ε/, (2) native Japanese speakers producing a Japanese vowel (/e⊤/), and (3) native Japanese speakers learning English, producing /ε/. All three groups showed similar production patterns when F1 was decreased; however, when F1 was increased, the Japanese groups did not compensate as much as the native English speakers. Due to this asymmetry, the hypothesis that the compensatory production for formant perturbation operates at a purely acoustic level was rejected. Rather, some level of phonological processing influences the feedback processing behavior. PMID:22087926

  12. A PC parallel port button box provides millisecond response time accuracy under Linux.

    PubMed

    Stewart, Neil

    2006-02-01

    For psychologists, it is sometimes necessary to measure people's reaction times to the nearest millisecond. This article describes how to use the PC parallel port to receive signals from a button box to achieve millisecond response time accuracy. The workings of the parallel port, the corresponding port addresses, and a simple Linux program for controlling the port are described. A test of the speed and reliability of button box signal detection is reported. If the reader is moderately familiar with Linux, this article should provide sufficient instruction for him or her to build and test his or her own parallel port button box. This article also describes how the parallel port could be used to control an external apparatus.

  13. Interdependency between Risk Assessments for Self and Other in the Field of Comparative Optimism: The Contribution of Response Times

    ERIC Educational Resources Information Center

    Spitzenstetter, Florence; Schimchowitsch, Sarah

    2012-01-01

    By introducing a response-time measure in the field of comparative optimism, this study was designed to explore how people estimate risk to self and others depending on the evaluation order (self/other or other/self). Our results show the interdependency between self and other answers. Indeed, while response time for risk assessment for the self…

  14. Intramolecular stable isotope distributions detect plant metabolic responses on century time scales

    NASA Astrophysics Data System (ADS)

    Schleucher, Jürgen; Ehlers, Ina; Augusti, Angela; Betson, Tatiana

    2014-05-01

    Plants respond to environmental changes on a vast range of time scales, and plant gas exchanges constitute important feedback mechanisms in the global C cycle. Responses on time scales of decades to centuries are most important for climate models, for prediction of crop productivity, and for adaptation to climate change. Unfortunately, responses on these timescale are least understood. We argue that the knowledge gap on intermediate time scales is due to a lack of adequate methods that can bridge between short-term manipulative experiments (e.g. FACE) and paleo research. Manipulative experiments in plant ecophysiology give information on metabolism on time scales up to years. However, this information cannot be linked to results from retrospective studies in paleo research, because little metabolic information can be derived from paleo archives. Stable isotopes are prominent tools in plant ecophysiology, biogeochemistry and in paleo research, but in all applications to date, isotope ratios of whole molecules are measured. However, it is well established that stable isotope abundance varies among intramolecular groups of biochemical metabolites, that is each so-called "isotopomer" has a distinct abundance. This intramolecular variation carries information on metabolic regulation, which can even be traced to individual enzymes (Schleucher et al., Plant, Cell Environ 1999). Here, we apply intramolecular isotope distributions to study the metabolic response of plants to increasing atmospheric [CO2] during the past century. Greenhouse experiments show that the deuterium abundance among the two positions in the C6H2 group of photosynthetic glucose depends on [CO2] during growth. This is observed for all plants using C3 photosynthesis, and reflects the metabolic flux ratio between photorespiration and photosynthesis. Photorespiration is a major C flux that limits assimilation in C3 plants, which encompass the overwhelming fraction of terrestrial photosynthesis and the

  15. SEPARABLE RESPONSES TO ERROR, AMBIGUITY, AND REACTION TIME IN CINGULO-OPERCULAR TASK CONTROL REGIONS

    PubMed Central

    Neta, Maital; Schlaggar, Bradley L.; Petersen, Steven E.

    2014-01-01

    The dorsal anterior cingulate (dACC), along with the closely affiliated anterior insula/frontal operculum have been demonstrated to show three types of task control signals across a wide variety of tasks. One of these signals, a transient signal that is thought to represent performance feedback, shows greater activity to error than correct trials. Other work has found similar effects for uncertainty/ambiguity or conflict, though some argue that dACC activity is, instead, modulated primarily by other processes more reflected in reaction time. Here, we demonstrate that, rather than a single explanation, multiple information processing operations are crucial to characterizing the function of these brain regions, by comparing operations within a single paradigm. Participants performed two tasks in an fMRI experimental session: (1) deciding whether or not visually presented word pairs rhyme, and (2) rating auditorily presented single words as abstract or concrete. A pilot was used to identify ambiguous stimuli for both tasks (e.g., word pair: BASS/GRACE; single word: CHANGE). We found greater cingulo-opercular activity for errors and ambiguous trials than clear/correct trials, with a robust effect of reaction time. The effects of error and ambiguity remained when reaction time was regressed out, although the differences decreased. Further stepwise regression of response consensus (agreement across participants for each stimulus; a proxy for ambiguity) decreased differences between ambiguous and clear trials, but left error-related differences almost completely intact. These observations suggest that trial-wise responses in cinguloopercular regions monitor multiple performance indices, including accuracy, ambiguity, and reaction time. PMID:24887509

  16. Progesterone in experimental permanent stroke: a dose-response and therapeutic time-window study

    PubMed Central

    Wali, Bushra; Ishrat, Tauheed; Won, Soonmi; Stein, Donald G.

    2014-01-01

    Currently, the only approved treatment for ischaemic stroke is tissue plasminogen activator, a clot-buster. This treatment can have dangerous consequences if not given within the first 4 h after stroke. Our group and others have shown progesterone to be beneficial in preclinical studies of stroke, but a progesterone dose-response and time-window study is lacking. We tested male Sprague-Dawley rats (12 months old) with permanent middle cerebral artery occlusion or sham operations on multiple measures of sensory, motor and cognitive performance. For the dose-response study, animals received intraperitoneal injections of progesterone (8, 16 or 32 mg/kg) at 1 h post-occlusion, and subcutaneous injections at 6 h and then once every 24 h for 7 days. For the time-window study, the optimal dose of progesterone was given starting at 3, 6 or 24 h post-stroke. Behavioural recovery was evaluated at repeated intervals. Rats were killed at 22 days post-stroke and brains extracted for evaluation of infarct volume. Both 8 and 16 mg/kg doses of progesterone produced attenuation of infarct volume compared with the placebo, and improved functional outcomes up to 3 weeks after stroke on locomotor activity, grip strength, sensory neglect, gait impairment, motor coordination and spatial navigation tests. In the time-window study, the progesterone group exhibited substantial neuroprotection as late as 6 h after stroke onset. Compared with placebo, progesterone showed a significant reduction in infarct size with 3- and 6-h delays. Moderate doses (8 and 16 mg/kg) of progesterone reduced infarct size and improved functional deficits in our clinically relevant model of stroke. The 8 mg/kg dose was optimal in improving motor, sensory and memory function, and this effect was observed over a large therapeutic time window. Progesterone shows promise as a potential therapeutic agent and should be examined for safety and efficacy in a clinical trial for ischaemic stroke. PMID:24374329

  17. Time-response of cultured deep-sea benthic foraminifera to different algal diets

    NASA Astrophysics Data System (ADS)

    Heinz, P.; Hemleben, Ch; Kitazato, H.

    2002-03-01

    The vertical distribution of benthic foraminifera in the surface sediment is influenced by environmental factors, mainly by food and oxygen supply. An experiment of three different time series was performed to investigate the response of deep-sea benthic foraminifera to simulated phytodetritus pulses under stable oxygen concentrations. Each series was fed constantly with one distinct algal species in equivalent amounts. The temporal reactions of the benthic foraminifera with regard to the vertical distribution in the sediment, the total number, and the species composition were observed and compared within the three series. Additionally, oxygen contents and bacterial cell numbers were measured to ensure that these factors were invariable and did not influence foraminiferal communities. The addition of algae leads to higher population densities 21 days after food was added. Higher numbers of individuals were probably caused by higher organic levels, which in turn induced reproduction. A stronger response is found after feeding with Amphiprora sp. and Pyramimonas sp., compared to Dunaliella tertiolecta. At a constant high oxygen supply, no migration to upper layers was observed after food addition, and more individuals were found in deeper layers. The laboratory results thus agree with the predictions of the TROX-model. An epifaunal microhabitat preference was shown for Adercotryma glomerata. Hippocrepina sp. was spread over the entire sediment depth with a shallow infaunal maximum. Melonis barleeanum preferred a deeper infaunal habitat. Bacterial cell concentrations were stable during the laboratory experiments and showed no significant response to higher organic fluxes.

  18. T cells translate individual, quantal activation into collective, analog cytokine responses via time-integrated feedbacks

    PubMed Central

    Tkach, Karen E; Barik, Debashis; Voisinne, Guillaume; Malandro, Nicole; Hathorn, Matthew M; Cotari, Jesse W; Vogel, Robert; Merghoub, Taha; Wolchok, Jedd; Krichevsky, Oleg; Altan-Bonnet, Grégoire

    2014-01-01

    Variability within isogenic T cell populations yields heterogeneous ‘local’ signaling responses to shared antigenic stimuli, but responding clones may communicate ‘global’ antigen load through paracrine messengers, such as cytokines. Such coordination of individual cell responses within multicellular populations is critical for accurate collective reactions to shared environmental cues. However, cytokine production may saturate as a function of antigen input, or be dominated by the precursor frequency of antigen-specific T cells. Surprisingly, we found that T cells scale their collective output of IL-2 to total antigen input over a large dynamic range, independently of population size. Through experimental quantitation and computational modeling, we demonstrate that this scaling is enforced by an inhibitory cross-talk between antigen and IL-2 signaling, and a nonlinear acceleration of IL-2 secretion per cell. Our study reveals how time-integration of these regulatory loops within individual cell signaling generates scaled collective responses and can be leveraged for immune monitoring. DOI: http://dx.doi.org/10.7554/eLife.01944.001 PMID:24719192

  19. A phase transition model for the speed-accuracy trade-off in response time experiments.

    PubMed

    Dutilh, Gilles; Wagenmakers, Eric-Jan; Visser, Ingmar; van der Maas, Han L J

    2011-03-01

    Most models of response time (RT) in elementary cognitive tasks implicitly assume that the speed-accuracy trade-off is continuous: When payoffs or instructions gradually increase the level of speed stress, people are assumed to gradually sacrifice response accuracy in exchange for gradual increases in response speed. This trade-off presumably operates over the entire range from accurate but slow responding to fast but chance-level responding (i.e., guessing). In this article, we challenge the assumption of continuity and propose a phase transition model for RTs and accuracy. Analogous to the fast guess model (Ollman, 1966), our model postulates two modes of processing: a guess mode and a stimulus-controlled mode. From catastrophe theory, we derive two important predictions that allow us to test our model against the fast guess model and against the popular class of sequential sampling models. The first prediction--hysteresis in the transitions between guessing and stimulus-controlled behavior--was confirmed in an experiment that gradually changed the reward for speed versus accuracy. The second prediction--bimodal RT distributions--was confirmed in an experiment that required participants to respond in a way that is intermediate between guessing and accurate responding.

  20. Reproducing Actual Morphology of Planetary Lava Flows

    NASA Astrophysics Data System (ADS)

    Miyamoto, H.; Sasaki, S.

    1996-03-01

    Assuming that lava flows behave as non-isothermal laminar Bingham fluids, we developed a numerical code of lava flows. We take the self gravity effects and cooling mechanisms into account. The calculation method is a kind of cellular automata using a reduced random space method, which can eliminate the mesh shape dependence. We can calculate large scale lava flows precisely without numerical instability and reproduce morphology of actual lava flows.